Environmental
Load Reduction
Technology

Multi-Purpose
Coal Utilization
Technology

CCT
Iron Making andGeneral Industry
Technology

Clean Coal Technology

Co-production
SystemClean Coal Technologies in Japan Technology Innovation in the Coal Industry

Technologies for
Coal Resources
Development

Clean Coal Technologies in Japan
Technology Innovation in the Coal Industry

Coal Fired Power
Generation
Technology

Basic Technology
for Advanced Coal
Utilization

Meiji Yasuda Seimei Mita Building 9F,
3-14-10 Mita, Minato-ku, Tokyo 108-0073 Japan
TEL. +81-3-6400-5193 FAX. +81-3-6400-5207
E-mail: jcoal-info@jcoal.or.jp
URL: http://www.jcoal.or.jp

Japan Coal Energy Center

Japan Coal Energy Center

Japan Coal Energy Center

Clean Coal Technologies in Japan
Technological Innovation in the Coal Industry(4) Multi-purpose Coal Utilization Technologies

Preface ---------------------------------------------------------------------------2

A. Liquefaction Technologies
Part 1 CCT Classifications -----------------------------------------------3

4A1. Coal Liquefaction Technology Development in Japan -------57(1) CCT Classifications in the Coal Product Cycle --------------------3

4A2. Bituminous Coal Liquefaction Technology (NEDOL) ---------59(2) Clean Coal Technology Systems --------------------------------------5

4A3. Brown Coal Liquefaction Technology (BCL) -------------------61(3) CCT in the Marketplace --------------------------------------------------6

4A4. Dimethyl Ether Production Technology (DME) ----------------63(4) CCT in Japanese Industries --------------------------------------------7

B. Pyrolysis Technologies(5) Environmental Technologies ------------------------------------------11

4B1. Multi-purpose Coal Conversion Technology (CPX) ----------65(6) International Cooperation ----------------------------------------------13

4B2. Efficient Co-production with Coal Flash Partial

Part 2 CCT Overview -------------------------------------------------------15

C. Powdering, Fluidization, and Co-utilization Technologies(1) Technologies for Coal Resources Development

4C1. Coal Cartridge System (CCS) -------------------------------------69

1A1. Coal Resource Exploration Technology -------------------------15

4C2. Coal Water Mixture Production Technology (CWM) ----------70

1A2. Coal Production Technology ----------------------------------------17

4C3. Briquette Production Technology --------------------------------71

1A3. Mine Safety Technology ---------------------------------------------19

4C4. Coal and Woody Biomass Co-firing Technology -------------73

1A4. Environment-friendly Resource Development Technology --21

D. De-ashing and Reforming Technologies(2) Coal-fired Power Generation Technologies

4D1. Hyper-coal-based High-efficiency Combustion

Hydropyrolysis Technology (ECOPRO) --------------------------67

Technology (Hyper-coal) --------------------------------------------75

A. Combustion Technologies

4D2. Low-rank Coal Upgrading Technology (UBC Process) ------77

2A1. High Efficiency Pulverized Coal-fired Power Generation Technology(5) Environmental Protection Technologies(Ultra Super Critical Steam Condition) ---------------------------23
2A2. Circulating Fluidized-bed Combustion Technology (CFBC) ---25

A. CO2 Recovery Technologies

2A3. Internal Circulating Fluidized-bed Combustion Technology (ICFBC) --26

5A1. Hydrogen Production by Reaction Integrated Novel
Gasification Process (HyPr-RING) --------------------------------79

2A4. Pressurized Internal Circulating Fluidized-bed Combustion
Technology (PICFBC) -------------------------------------------------28

5A2. CO2 Recovery and Sequestration Technology ----------------81

2A5. Coal Partial Combustor Technology (CPC) ---------------------29

5A3. CO2 Conversion Technology ---------------------------------------82

2A6. Pressurized Fluidized-bed Combustion Technology (PFBC) ---31

5A4. Oxy-fuel Combustion (Oxygen-firing of Conventional
PCF System) -----------------------------------------------------------83

2A7. Advanced Pressurized Fluidized-bed Combustion

B. Flue Gas Treatment and Gas Cleaning Technologies

Technology (A-PFBC) -------------------------------------------------33
B. Gasification Technologies

5B1. SOx Reduction Technology ----------------------------------------85

2B1. Hydrogen-from-Coal Process (HYCOL) -------------------------35

5B2. NOx Reduction Technology ----------------------------------------87

2B2. Integrated Coal Gasification Combined Cycle (IGCC) -------37

5B3. Simultaneous De-SOx and De-NOx Technology -------------89

2B3. Multi-purpose Coal Gasification Technology Development (EAGLE) --39

5B4. Particulate Treatment Technology and Trace Element
Removal Technology -------------------------------------------------91

2B4. Integrated Coal Gasification Fuel Cell Combined Cycle

5B5. Gas Cleaning Technology ------------------------------------------93

Electric Power Generating Technology (IGFC) -----------------41

C. Technologies to Effectively Use Coal Ash

2B5. Next-generation, High-efficiency Integrated Coal Gasification

5C1. Coal Ash Generation Process and Application Fields -------95

Electric Power Generating Process (A-IGCC/A-IGFC) -------42(3) Iron Making and General Industry Technologies

5C2. Effective Use of Ash in Cement/Concrete ----------------------97

A. Iron Making Technologies

5C3. Effective Use of Ash in Civil Engineering/Construction

3A1. Formed Coke Process (FCP) ---------------------------------------43

and Other Applications ----------------------------------------------99

3A2. Pulverized Coal Injection for Blast Furnaces (PCI) ------------45

5C4. Technology to Recover Valuable Resources from Coal Ash -----101

3A3. Direct Iron Ore Smelting Reduction Process (DIOS) ---------47(6) Basic Technologies for Advanced Coal Utilization

3A4. Super Coke Oven for Productivity and Environment

6A1. Modeling and Simulation Technologies for Coal Gasification ----103(7) Co-production Systems

Enhancement toward the 21st Century (SCOPE21) ----------49
3A5. Coke Dry Quenching Technology (CDQ) ------------------------51

7A1. Co-generation Systems -------------------------------------------107

B. General Industry Technologies

7A2. Co-production Systems -------------------------------------------109

3B1. Fluidized-bed Advanced Cement Kiln System (FAKS) -------53
Part 3 Future Outlook for CCT ----------------------------------------111

3B2. New Scrap Recycling Process (NSR) ---------------------------55

Definitions, Conversions -----------------------------------------------1141

Preface
The New Energy and Industrial Technology Development Organization(NEDO) and the Japan Coal Energy Center (JCOAL) have jointly prepared thisguide as a review of the history of "Clean Coal Technology (CCT)" in Japan, tosystematically describe the present state of CCT insofar as possible, and toprovide useful material for novel technological innovation.
NEDO and JCOAL hope this brochure will be helpful in elucidating why
Japan’s CCT is an attractive technology in the ever-increasing complexity ofcoal utilization owing to global warming and other environmental issues. NEDO
and JCOAL also hope this brochure will encourage rapid progress in CCTdevelopment and the foundation of innovative clean coal utilization systems.
As described herein, CCT development in Japan has reached the world’s
highest level of technological superiority, making the technology highly
attractive to Asian countries that depend on coal as an energy source. In
Japan, coal consumption has rapidly increased since 1998, with gross thermal
power generation efficiency increasing from approximately 38% to 41% overthe past dozen or so years. In addition, emissions of CO2, SOx and NOx per
generated power unit from thermal power plants are far below the level ofother industrialized countries. In this regard, CCT is expected to become
standardized worldwide, satisfying both economic and environmental
requirements by reducing CO2 emissions and maintaining GDP growth.
Technological innovation has no boundaries; significant progress can beattained sustainably and progressively. Patient, consistent efforts to build ontechnological developments can support a continually evolving society. NEDO
and JCOAL are confident this publication will contribute to CCT development
and we look forward to the emergence of dramatic technological innovations in
the coal industry.

1.40

Increase in coal consumption and economic, environmental, and energy trends in Japan (1990-2004)
1.35

1.30

Coal consumption

1.25

Electric power
generation

1.20

Total primary energy supply

1.15

CO2 emissions
1.10

GDP

1.05

Thermal power
generation efficiency

1.00

CO2 emissions/GDP

0.95

0.90
1990

1991

1992

1993

1994

1995

1996

1997

2

1998

1999

2000

2001

2002

2003
2004
Fiscal year

Part 1 CCT Classifications
CCT Classifications in the Coal Product Cycle

Gasification

Liquefaction

Slurry preparation

EAGLE
Coal exploration

Coal mine

Pulverizing/Briquetting

DME
Coal carrier

Carbonization

Cave-in prediction

Coal preparation plant

Coal train

DME/GTLSCOPE21

Technologies for Coal
Resources Development

Multi-purpose Coal
Utilization Technologies

Coal Resource Exploration Technology

1A1

Processing,reformingand converting

Crushing,
transportationand storage

Exploration, mining,safety and preparation

1A2 Coal Production Technology

Coal Gasification andHydrogenation
Technologieies

1A3

Mine Safety Technology

1A3
1A4

Environment-friendly Resource
Development Technology
Liquefaction
Technologies

Physical properties of coal
Anthracite

Bituminous
coal

Brown coal

1.5-1.8

1.2-1.7

0.8-1.5

Apparent specific gravity-

0.75-0.80

0.55-0.75

Specific heat

0.22-0.24

0.24-0.26

0.26-0.28

Thermal conductivity (W/m.K)-

1.26-1.65-

Ignition point (oC)

400-450

300-400

250-300

Heating value (kcal/kg (dry basis))

8,200-8,500

7,500-8,800

5,500-7,500

Specific gravity

Coal classification by degree of carbonization
Classification Heating value (kcal/kg(dry basis))
Fuel ratio
Anthracite
4.0 or greater
1.5 or greater
8,400 or greater
Bituminous
1.5 or lesscoal
1.0 or greater
8,100 or greater
1.0 or less
1.0 or greater
7,800 or greater
Subbituminous
1.0 or lesscoal
7,300 or greater
6,800 or greater
Brown coal
5,800 or greater

Pyrolysis
Technologies

Caking property
Non-caking

2B1

Hydrogen-from-Coal Process (HYCOL)

2B3

Multi-purpose Coal Gasification
Technology Development (EAGLE)

5A1

Hydrogen Production by Reaction
Integrated Novel Gasification
Process (HyPr-RING)

4A1

Coal Liquefaction Technology
Development in Japan

4A2

Bituminous Coal Liquefaction
Technology (NEDOL)

4A3

Brown Coal Liquefaction
Technology (BCL)

4A4

Dimethyl Ether Production
Technology (DME)

4B1

Multi-purpose Coal Conversion
Technology (CPX)

4B2

Efficient Co-production with
Coal Flash Partial Hydropyrolysis
Technology (ECOPRO)

4C1

Coal Cartridge System (CCS)

4C2

Coal Water Mixture Production
Technology (CWM)

4C3

Briquette Production Technology

4C4

Coal and Woody Biomass
Co-firing Technology

4D1

Hyper-coal-based High-efficiency
Combustion Technology (Hyper-coal)

4D2

Low-rank Coal Upgrading Technology(UBC Process)

6A1

Modeling and Simulation Technologies
for Coal Gasification

Strong-caking
CakingWeak-caking
Weak-caking
Non-caking
Non-caking

Powdering, Fluidization
and Co-utilization
Technologies

Non-caking

Coal classification by utilization (expressed as coal)
Source: Trade Statistics

Anthracite

Anthracite

Steam coal

Coking coal

Source: TEXT report

Coking coal A

Ash content of 8% or less
Strong-caking
coal for coke Ash content exceeding 8%

Coking coal B
Coking coal C

Bituminous
coal

Other coalfor cokeAsh content of 8% or less

Coking coal D
Steam coal A

Other

Ash content exceeding 8%

Steam coal B
Steam coal C

De-ashing and Reforming
Technologies

Ash content exceeding 8%
Basic Technologies
for Advanced Coal Utilization

Ash content of 8% or less
Other coal

Ash content exceeding 8%

3

Clean Coal Technologies in Japan
CO2
reduction

Flue gas treatment

Electrostatic
precipitator
Power plant

Enhanced Oil Recovery (EOR) by CO2

Cement plant

Effective
coal ash use
Flue gas denitration facility

Iron works

Chemical plant

Flue gas desulfurization facility

Environmental
countermeasures

Utilization

High-efficiency
Utilization Technologies

2A1

High Efficiency Pulverized Coal-fired
Power Generation Technology(Ultra Super Critical Steam Condition)

Coal-fired Power
Generation Technologies

2A2

Circulating Fluidized-bed Combustion
Technology (CFBC)

2A3

Internal Circulating Fluidized-bed
Combustion Technology (ICFBC)

Yokohama Landmark Tower

CO2 Recovery
Technologies
5A1

Hydrogen Production by Reaction
Integrated Novel Gasification
Process (HyPr-RING)

5A2

CO2 Recovery and Sequestration
Technology

5A3

CO2 Conversion Technology

5A4

Oxy-fuel Combustion(Oxygen-firing of Conventional
PCF System)

5B1

SOx Reduction Technology

5B2

NOx Reduction Technology

Pressurized Internal Circulating Fluidized2A4
bed Combustion Technology (PICFBC)
Combustion
Technologies

Gasification
Technologies

Iron Making
Technologies

General Industry
Technologies

Co-production
Systems

2A5

Coal Partial Combustor Technology (CPC)

2A6

Pressurized Fluidized-bed Combustion
Technology (PFBC)

2A7

Advanced Pressurized Fluidized-bed
Combustion Technology (A-PFBC)

4D1

Hyper-coal-based High-efficiency
Combustion Technology (Hyper-coal)

2B1

Hydrogen-from-Coal Process (HYCOL)

2B2

Integrated Coal Gasification
Combined Cycle (IGCC)

2B4

Integrated Coal Gasification Fuel Cell
Combined Cycle Electric Power
Generating Technology (IGFC)

2B5

Next-generation, High-efficiency Integrated
Coal Gasification Electric Power Generating
Process (A-IGCC/A-IGFC)

5B3

Simultaneous De-SOx and
De-NOx Technology

3A1

Formed Coke Process (FCP)

5B4

Particulate Treatment Technology andTrace Element Removal Technology

3A2

Pulverized Coal Injection for
Blast Furnaces (PCI)
Direct Iron Ore Smelting Reduction
Process (DIOS)

5B5

3A3

Gas Cleaning Technology

3A4

Super Coke Oven for Productivity and Environment
Enhancement toward the 21st Century (SCOPE21)

5C1

Coal Ash Generation Process
and Application Fields

3A5

Coke Dry Quenching Technology (CDQ)

3B1

Fluidized-bed Advanced Cement
Kiln System (FAKS)

5C2

Effective Use of Ash in Cement/
Concrete

3B2

New Scrap Recycling Process (NSR)
5C3

Effective Use of Ash in Civil
Engineering/Construction
and Other Applications

5C4

Technology to Recover Valuable
Resources from Coal Ash

7A1

Co-generation Systems

7A2

Co-production Systems

Flue Gas Treatment andGas Cleaning Technologies

Technologies to Effectively
Use Coal Ash

4

Part 1 CCT Classifications
Clean Coal Technologies in Japan

Clean Coal Technology Systems

Coal cycle

TargetMiningCoal preparation

Crushing

Technology for low emission
coal utilization

Conventional coal preparation techniques(jig, flotation, heavy media separation)
Preparation process control technology

Preparation

Diversification of energy
sources/expansion of

Bio-briquetting

Deashing, reforming
and processing

application fields

Upgrading brown coal (UBC) Carbonization briquetting
Hyper-coal

Reforming

Coal cartridge system (CCS)

Handling

Coal liquid mixture (CWM, COM)
Desulfurized CWM

Ease of handling
Bituminous coal liquefaction technology (NEDOL)

Liquefaction

Brown coal liquefaction technology (BCL)
Upgrading of coal-derived liquids

Conversion

Integrated coal gasification combined cycle power generation
technology (IGCC)

More efficient use of energy/

Hydrogen-from-coal process (HYCOL)

Gasification

CO2 reduction(global warming countermeasure)

Multi-purpose coal gasification technology development (EAGLE)
Multi-purpose coal conversion (CPX)

Pyrolysis

Efficient Co-production with coal flash partialhydropyrolysis technology (ECOPRO)
Topping combustion
Pressurized fluidizedFluidized-bed boiler
O2/CO2
bed combustion (PFBC)
combustion
Fluidized-bed boiler
Fluidized-bed advanced cement kiln system (FAKS)

High-efficiency
combustion

Combustion

Reduction in SOx, NOx,
and waste(acid rain and global
warming countermeasures)

Direct iron ore smelting
reduction process (DIOS)
Advanced flue gas
treatment

Flue gas
treatment

Dry desulfurization
denitration

Wet desulfurization
Denitration

Hot gas cleaning technology
Dust removal
Alkaline, etc. removal technology

Pollutant reduction
Ash utilization

Coal ash utilization technologies

Degree of technological maturity

Proven reserves and R/P (ratio of reserves to production)of major energy resources

World reserves of coal, oil, and natural gas resources(Source: BP 2005)(Unit: 100 million tons oil equivalent)
2,010

Local reserves

World reserves
North America
Latin America
EuropeFormer Soviet Union
Middle East
AfricaAsia PacificAnnual production
rate
R/P

Oil

Natural gas

1,727

9.091 trillion tons 1,188.6 billion barrels 180 trillion m3 459 million tons
27.8％
2.3％
7.1％
24.5％
0.0％
5.6％
32.7％

3.9％
9.7％
1.6％
10.0％
61.7％
9.4％
3.5％

3.9％
4.2％
2.9％
32.4％
40.6％
7.8％
7.9％

29.3 billion barrels
5.54 billion tons (80.3 million B/D) 2.7 trillion m3
164 years

40.5 years

66.7 years

17.1％
3.6％
2.8％
28.7％
0.2％
20.5％
27.2％

1,781

1,099

Uranium

2,078

432
99
576

1,000

190

80 66

655
647

Europe, FSU

29
352 127
149 Middle East
Africa0.036 million tons

6,363

Russia 802

North America 36 48
1,619
U.S.A.
1,616

2320
China

7 8
India

128
55
Asia and Oceania
550

144
139 64342

85 years

Latin America
0 0Oil, natural gas, and coal data source: BP Statistics 2005
Uranium: OECD/NEA, IAEA URANIUM 2003

South Africa

5 22
Australia

Coal
OilNatural gas

CoalWorldwide

5

CCT in the Marketplace

Clean Coal Technologies in Japan

Technological difficulty
Domestic coal conversion and reforming technology

Domestic coal utilization technology
HyPr-RING

Hyper coal power generation

P-CPC
Technological and economicaldifficultes remain

IGFC
HYCOL

Hyper-coal
A-PFBC

Gasification furnace (fluidized bed, spouted bed)
IGCC

Technology at a practical use level

DME

USC
FBC

PICFB
I C F B
Cement raw material P C F B C
Gypsum board
CFBC

Commercialization
technology

Deashed CWM
CWMCOM

Melting and fiber-forming

Flue gas
treatment

FGC melting and mixing treatment
Fluidized-bed solidification material

CCS
Pneumatic transfer

NEDOL
BCL

CPX

NSR
FAKS

Advanced fluegas treatment

PCI

Economic difficulty

PFBC

Economic difficulty

SCOPE21
DIOS
Formed-coke

EAGLE

Artificial aggregate

Briquette
Bio-coal
Wet coal preparationCC

Simplified dry desulfurization

Tt

ra n

sfe

r

Brown coal dewatering
DME

Cost reduction technology development

GTL

Dry coal preparation
Hyper Coal

Overseas demonstration(International cooperative demonstration)
Conventional technology
development region

Overseas coal conversion and reforming technology

Overseas coal utilization technology

Technological difficulty
Coal Production and Consumption by Country in 2004 (Total coal production worldwide: 5.508 trillion tons; Total coal consumption worldwide: 5.535 trillion tons)
and Japanese Coal Imports (Japan’s total coal imports: 184 million tons)
1,956

280

5,508 5,535

Source: IEA Coal Information 2005

1,889

1,008 1,006
237
66 55

161

25 61

CanadaFormer USSR

250
211
Poland

9.

7（
5.

%）
3.3
（
0
.
6

3%
）

South Africa%）(Unit: million tons)

Chemicals 0.91
130.57104.1（56.7%）

Electric power 82.19

129

22
Indonesia

Others 4.65
Cement/ceramics 6.18

152.36 154.57

Coal demand trend in Japan

111.45115.48

355
93.94

90.79

136
Australia

82.25

Steam coal

223
156

174.28163.17

Pulp/paper

Gas/coke
Iron making 80.35

Coking coal

0

）
1%
0.
.1（

World

Japan

China
India

U.S.A

）
4.8（2.6%

）
% 184
4.3
0
8.0（

(consumption)(production)

402 432

Germany

26
.4（
14
.4

U.K.

145

FY1970

’75

’80

’85

’90

’95

’00

’01

’02

’03

(Source : Coal Note 2003)

6

Part 1 CCT Classifications
CCT in Japanese Industries

Power generation field
Location of coal-fired power plants
Figures in parentheses indicate power generation capacity(MW) at the end of FY2005.

Sunagawa (250)
Naie (350)
Tomatou Atsuma(1,735)

Nanao Ota (1,200)
Toyama Shinko Kyodo (500)
Noshiro (1,200)
Tsuruga (1,200)
Maizuru (under construction)
Takasago (500)
Mizushima (281)
Osaki (259)
Takehara (1,300)
Misumi (1,000)

Coal consumption (million tons)

160

1800

Total domestic coal consumption

1600

140

1400

120

1200

Generated power
100

1000

80
60

800

Coal consumption

600

40

400

20

200

0

Generated power (GkWh)

180

Sakata (700)Shin-onoda (1,000)
Shimonoseki (175)
Tobata Kyodo (156)
Kanda (360)Minato (156)
Matsuura (2,700)
Matsushima (1,000)

Sendai (350)
Shinchi (2,000)
Haramachi (2,000)
Hirono (under construction)
Nakoso (1,450)
Hitachi Naka (1,000)
Isogo (600)

Hekinan (3,100)
Tachibanawan (2,100+700)
Niihama Higashi (42.5)
Niihama Nishi (150)
Saijo (406)

Reihoku (1,400)

Kin (440)
Ishikawa (312)
Gushikawa (312)01990 '91 '92 '93 '94 '95 '96 '97 '98 '99 '00 '01 '02 '03

Coal consumption in power generation sector and generated power

Iron making field
Location of iron works
Figures in parentheses indicate crude steel production(MT) as of FY2005.

Kobe Steel (Kobe) (1,062,063)
Kobe Steel (Kakogawa) (5,397,267)
Sumitomo Metal(Kashima) (6,820,450)

JFE Steel (Mizushima) (8,423,478)

JFE Steel (Chiba) (4,186,020)

JFE Steel (Fukuyama) (9,885,534)

Total domestic coal consumption

160

140

140

120

120

Crude steel production

100

100

80

80

Coal consumption

60

60

40

40

20

20
0

0

Crude steel production (million tons)

Coal consumption (million tons)

160

Nippon Steel (Kimitsu)(9,195,689)

180

180

Nippon Steel (Yawata)(3,514,941)

JFE Steel (Keihin) (3,472,723)
Nippon Steel (Nagoya) (5,651,300)
Sumitomo Metal (Wakayama) (3,412,887)
Nippon Steel (Oita) (8,012,585)

1990 '91 '92 '93 '94 '95 '96 '97 '98 '99 '00 '01 '02 '03

Coal consumption in iron making sector and crude steel production

7

Clean Coal Technologies in Japan

Coal-fired power generation technologies

2A1

High Efficiency Pulverized Coal-fired Power Generation
Technology (Ultra Super Critical Steam)

2A4

Pressurized Internal Circulating Fluidizedbed Combustion Technology (PICFBC)

2A2

Circulating Fluidized-bed Combustion
Technology (CFBC)

2A5

Coal Partial Combustor Technology (CPC)

2A3Internal Circulating Fluidized-bed
Combustion Technology (ICFBC)

2A6

Pressurized Fluidized-bed Combustion
Technology (PFBC)

2A7

Advanced Pressurized Fluidized-bed
Combustion Technology (A-PFBC)

Combustion

Steam
coal

furnaceboilerCoal
Gascleaning

Fuel
cells

Stack

Coal
gasification

Pulverizedcoalfurnace
5B5

Gas

Steam

turbineturbineGenerator

Gas Cleaning Technology

Electric
power

2B4

Integrated Coal Gasification Fuel Cell Combined Cycle
Electric Power Generating Technology (IGFC)

2B2

Integrated Coal Gasification Combined
Cycle (IGCC)

2B5

Next-generation, High-efficiency Integrated Coal Gasification
Electric Power Generating Process (A-IGCC/A-IGFC)

2B3

Multi-purpose Coal Gasification Technology
Development (EAGLE)

4D1

Hyper-coal-based High-efficiency
Combustion Technology (Hyper-coal)

2B1

Hydrogen-from-Coal Process (HYCOL)

Wastewater

Iron making technology
3A2

Pulverized Coal Injection
for Blast Furnaces (PCI)

3A1

Formed Coke Process (FCP)

Blast furnace
Cokingcoal

Pig iron

Formed-cokefurnaceConverter

PCIElectric
furnace

Iron and steel
Coal
SCOPE21
Slag

Steam
coal

DIOS
NSR
3A4

Super Coke Oven for Productivity and Environment
Enhancement toward the 21st Century (SCOPE21)

3A5

Coke Dry Quenching Technology (CDQ)

3A3

Direct Iron Ore Smelting
Reduction Process (DIOS)
3B2

8

New Scrap Recycling Process (NSR)Part 1 CCT Classifications
CCT in Japanese Industries

Cement production field
Location of cement plants
Figures in parentheses indicate clinker production capacity(1000 tons/yr) as of April 1, 2005.

Nittetsu Cement (Muroran) (968)Myojo Cement (Itoigawa) (2,108)
Denki Kagaku Kogyo (Omi) (2,703)

Taiheiyo Cement (Kamiiso) (3,944)
Mitsubishi Material (Aomori) (1,516)

Sumitomo Osaka Cement (Gifu) (1,592)

Hachinohe Cement (Hachinohe) (1,457)

Tsuruga Cement (Tsuruga) (816)

Taiheiyo Cement (Ofunato) (2,680)
Mitsubishi Material (Iwate) (670)

Tokuyama (Nanyo) (5,497)
Tosoh (2,606)

Hitachi Cement (Hitachi) (848)Sumitomo Osaka Cement (Tochigi) (1,489)
Chichibu Taiheiyo Cement (Chichibu) (800)
Taiheiyo Cement (Kumagaya) (2,267)
Mitsubishi Material (Yokoze) (1,213)
Taiheiyo Cement (Saitama) (1,655)
DC (Kawasaki) (1,108)

Ube Industries (1,612)
Ube Industries (4,872)

180
Coal consumption (million tons)

160

Total domestic coal consumption

160
140

140

120

120

Cement production

100

100

80

80

60

60
40

40

Coal consumption

20
0

20

1990 '91 '92 '93 '94 '95 '96 '97 '98 '99 '00 '01 '02 '03

Cement production (million tons)

180

0Coal consumption in cement production sector and cement production

Taiheiyo Cement (Fujiwara) (2,407)
Taiheiyo Cement (Tosa) (1,165)
Taiheiyo Cement (Kochi) (4,335)
Taiheiyo Cement (Tsukumi) (4,598)
Taiheiyo Cement (Saeki) (1,426)

Nippon Steel Blast Furnace Cement (Tobata) (808)
Mitsubishi Materials (Kyushu) (8,039)
Ube Industries (Kanda) (3,447)
Kanda Cement (Kanda) (1,085)
Kawara Taiheiyo Cement (Kawara) (800)
Mitsui Mining (Tagawa) (1,977)
Aso Cement (Tagawa) (1,412)

Ryukyu Cement(Yabu) (722)

Coal chemicals and other fields
Location of chemical complexes
Figures in parentheses indicate ethylene production capacity(1000 tons/yr) at the end of FY2005.

Mitsubishi Chemical (Mizushima) (450)Asahi Kasei (Mizushima)
Sanyo Petrochemical (443)4,600（20.3）（19.5）
520（19.7）（18.7）（19.0）

Coal energy supply (PJ)

（18.1）（17.8）（17.8）

4,000

Coal energy supply

3,800
3,600

3,200

1,235 1,242（17.0）
1,213（16.3）（16.3）
1,198（16.8）

3,000 1,122 1,131
2,800

1,248

1,239
1,228
1,195

1,252

1,214

CO2 emissions (Mt-C)

1,149

Nippon Petrochemicals (Kawasaki) (404)480

Tonen Chemical (Kawasaki) (478)460（16.6）（16.3）（17.1）（16.5）（17.5）（16.7）（16.7）

1,139

1990 '91 '92 '93 '94 '95 '96 '97 '98 '99 '00 '01 '02 '03

Mitsui Chemicals (Ichihara) (553)
Idemitsu Petrochemical (Chiba) (374)
Sumitomo Chemical(Anegasaki, Sodegaura) (380)

500

440
420
400

GDP (trillion yen)

GDP

4,200

3,400

Mitsui Chemicals(Iwakuni-otake) (623)
Idemitsu Petrochemical(Suo) (623)

540

4,400

Mitsubishi Chemical (Kashima) (828)Maruzen Petrochemical (Goi) (480)Keihin Ethylene (690)

Mitsubishi Chemical (Yokkaichi)
Tosoh (Yokkaichi) (493)
Mitsui Chemicals (Osaka)
Osaka Petrochemical (455)Showa Denko (Oita) (581)380
360
Ryukyu Cement (Yabu) (722)

Coal energy supply, GDP, and CO2 emissions in Japan
Figures in parentheses indicate coal’s percentage of primary energy.

9Clean Coal Technologies in Japan

Cement production technology
3B1

Fluidized-bed Advanced Cement Kiln System (FAKS)
Coal

Electric precipitator

Effective Use of Ash in Cement/Concrete

5C2Electric precipitator

Truck
GypsumLimestone
Clay
Iron rawmaterial

CementcoolerCoal millCementsilo

Dryer
Heavy oil tank

Recycled raw materials
Air
separator

Silo

Tanker
Raw material mill

Pre-heaterAirseparator
Rotarykiln

ClinkercoolerClinkersilo

Coal chemical process

Pre-pulverizing
mill

4A1

Coal Liquefaction Technology
Development in Japan

4A4

Dimethyl Ether Production
Technology (DME)

4A2

Bituminous Coal Liquefaction
Technology (NEDOL)

5A1

Hydrogen Production by Reaction Integrated
Novel Gasification Process (HyPr-RING)

4A3

Brown Coal Liquefaction
Technology (BCL)

Coal

Vent

Fractionation process
Raw material charge process
Medium distillate

Coal conversion process

Heavy distillate
Water

Separation, purification process

Air

High value-added product
BTX and mono- and di-cyclic components
Residue coal
Recycling
Wastewater
4B1

Multi-purpose Coal Conversion
Technology (CPX)

4B2 Efficient Co-production with Coal Flash Partial

Hydropyrolysis Technology (ECOPRO)

10

4D1

Hyper-coal-based High-efficiency
Combustion Technology (Hyper-coal)

4D2

Low-rank Coal Upgrading Technology(UBC Process)Part 1 CCT Classifications
Environmental Technologies

Efforts to reduce CO2 emissions[1] Reduction of CO2 generation by enhancing coalutilization efficiency,[2] Control of CO2 emissions generated through direct
coal burning by utilizing the carbon component in coalfor material production, and[3] Underground CO2 sequestration and storage bydecomposing and capturing CO2 contained in flue gas.
Japan also promotes the reduction of CO2 emissions
through international cooperation using the Kyoto
Mechanisms.

The Kyoto Protocol, which requires Japan to reducegreenhouse gas emissions, including carbon dioxide,
methane, nitrous oxide and alternative CFCs, by 6
percent from the 1990 level between 2008 and 2012,
came into effect on February 16, 2005.
Among these global warming gases, carbon dioxide(CO2) has the greatest impact on the environment. To
reduce emissions of CO2, Japan, with the most highly
advanced clean coal technologies in the world, ispromoting further technological developments, including:

Energy-derived CO2 emission trend in Japan

Source: CCT Journal Vol.11

Energy-derived CO2 emission trend in Japan
Source: General Energy Statistics of Japan (2004 edition)

A-IGFC up to
65%

2.55

1300.01280.0A-IGCC 1700oC-class
GT 57%

A-IGCC 1500oC-class GT 53%

55

IGFC 55%

50

45

IGCC 1500oC-class
GT wet gas cleaning 46%
IGCC demonstration
unit 1200oC-classIGCC
A-PFBC 1300oC-class GT 46%
GT dry gas cleaning 40.5%
1500oC-class
GT dry gas cleaning 48%

40
2000

2010
2020
Year of commercialization

2030

2.50
1260.01251.71240.02.45

1220.02.40
1200.01180.02.35

2.351160.0Co-production

Gas engine/GT &DME synthesis

Methane gas

CBM collection

BoilerPower
Synthetic fuel(DME, GIL)

CO2 storage in coal seamPower for consumers
and transportation

CO2

Gasification
Synthetic gas(H2, CO)CO-shift,
CO2 separation &collection

Source: IEO 2005

H2 fuel cells,
stationary fuel cells

H2 separation &refining

Nitrogenous fertilizer,
engineering plastic

Ammonia synthesis,
methanol synthesis
Chemical

CO2 capture and sequestration
Transportation
Land: liquefied CO2 pipelines
Marine: liquefied CO2 transport ships

1990

2001

2002

2010

2015

2020

2025

4,989

5,692

5,751

6,561

6,988

7,461

7,981

Canada

473

573

588

681

726

757

807

Western Europe

3,413

3,585

3,549

3,674

3,761

3,812

3,952

Russia

2,347

1,553

1,522

1,732

1,857

1,971

2,063

China

2,262

3,176

3,322

5,536

6,506

7,373

8,133

India

583

1,009

1,025

1,369

1,581

1,786

1,994

Japan

990

1,182

1,179

1,211

1,232

1,240

1,242

U.S.

Fuel cells

H2

BiogasCO2 emissions in major countries (million tons)

Power plants,
automobiles, etc.

FT synthesis,
DME synthesis

Methane gas

Separation and capture
Chemical absorption
Physical adsorption
Membrane separation
Oxygen burning

2.25
90 91 92 93 94 95 96 97 98 99 2000 2001 2002 2003 2004
Year

ST
GT

Coal

Pretreatment

CO2 emissions/real GDP

1120.0Power,
synthetic fuelFC

Coal seam

1140.0IGCC/IGFC

City gas

2.30

CO2 emissions

Source: JCOAL Journal, First issue

CO2 emissions/GDP (t- CO2/million yen)

60
CO2 emissions (million t- CO2)

Power generation efficiency [%]65

World total 21,460 24,072 24,409 30,201 33,284 36,023 38,790

Capture and Sequestration
Underground: aquifer,coal seam
Ocean: dissolution, diffusion,
hydride (on the sea floor)

CO2 emissions per generated power unit in major countries
Source: Federation of Electric Power Companies of Japan

CO2 fixation and CH4 collection
in coal seams

Power plants（kg-CO2/kWh）0.7Transportation
Injection

0.6

CO2 separation and capture(flue gas decarburization)

0.58

0.5
CH4 collection

Bore hole

Bore hole

0.46

0.47

0.43
0.39

0.4

CH4 utilization

0.3
CH4 replacement

0.21

0.2

CO2 fixation

0.1
Coal seam

0

0.06
U.S.

Germany

U.K.

France Canada

Italy

Japan

（2003）（2003）（2003）（2003）（2003）（2003）（2003）

11

Clean Coal Technologies in Japan

Coal preparation technologies

Flue gas treatment technologies

Reducing sulfur oxide emissions during coal utilization is an
important environmental conservation challenge. Coal
preparation is an environmental control technology that removes
iron pyrite particles that may be a source of ash content or
sulfur oxides before coal is used.

Emission reduction technology to remove dust, sulfur oxides, andnitrogen oxides has been developed by treating and combusting
flue gas from coal combustion through a superior process design.
Flue gas desulfurization
unit schematic diagram

Flue gas denitration
unit schematic diagram

Electrostatic precipitator
schematic diagram

NH3(Ammonia)
NO X
NO X

Electrode

NO X

NH 3

NO X

NH 3
NO X

NO X

Clean gas
(to stack)

NO X

NH 3

DC high voltage

NH 3

NO X

Pump

Catalyst

Discharge
electrode
Collected
coal ashCollecting
electrode

Mixed liquid of
limestone and water
H 2O

N2
N2

Flue gas

H 2O
N2

H 2O
H 2O

N2

GypsumFlotation machine

Pump

GypsumFlue gas (from boiler)

Electrostatic precipitator
Flue gas containing ash and dust passes between twoelectrodes that are charged by a high voltage current. The
negatively charged ash and dust are attracted toward anddeposited on the cathode. The ash and dust deposited on thecathode are tapped periodically, and are collected in the lower
section of the electrostatic precipitator and then subsequently
removed. The principle is the same as the phenomenon where
paper and dust adhere to a celluloid board electrostaticallycharged by friction.
Flue gas desulfurizer
Limestone is powderized to prepare a water-based mixture(limestone slurry). The mixture is injected into the flue gas toinduce a reaction between the limestone and the sulfur oxides
in the flue gas to form calcium sulfite, which is further reactedwith oxygen to form gypsum. The gypsum is then separated asa product.
Flue gas denitrizer
Ammonia is injected into the flue gas containing nitrogenoxides. The gas mixture is introduced to a metallic catalyst (asubstance which induces chemical reactions). The nitrogenoxides in the flue gas undergo catalyst-induced chemical
reactions, causing them to decompose into nitrogen and water.

Heavy media cyclone

Sludge coal collection and dehydration technologies
Coal preparation leaves an effluent containing pulverized coal.
Releasing the effluent into rivers and streams without treatment
may cause environmental problems. To resolve the issue, and toalso make effective use of this resource, a high-efficiency
sludge coal collection and dehydration technique is now underdevelopment.

Effluent thickener

Reaction formulae

4NO + 4NH3 + O2

Dehydrator

4N2 + 6H2O

(Nitrogen(Ammonia)monoxide)(Nitrogen gas)

6NO2 + 8NH3
(Nitrogen dioxide)

Effective coal ash utilization technologies

7N2 + 12H2O(Nitrogen gas)

Ash generated during coal combustion can be effectively used
as a raw material for cement and other products. The use of ash
for multiple purposes is under study.
Effective use of coal ash from power generation or general industries in Japan (FY2003)
Source: Survey report on actual usage of coal ash in Japan (JCOAL)

Emissions of SOx and NOx per generated power in major countries
Source; The Federation of Electric Power Companies of Japan（g/kWh）
4.5(Thermal power plants)

4.0

3.9

3.7

SOx
NOx

3.5
3.0

2.6

2.5
2.0

2.0 2.0
1.7

1.5

1.5
1.0
0.5
0

Cement raw material
5,876 70.1%
Other
Fertilizer, soil improvements, etc.
663
7.9%
172 2.1%
Other building
Other 7.9%
materials 19 0.2%
Agriculture, forestry Total 8,380
and fishery 2.1%
(thousand tons)
Building material
Construction 4.7%
boards 377 4.5%
CementCivil work
75.5%
Civil work materials,
9.8%
etc. 216 2.6%
Road and base
Cement admixture 308 3.7%
materials 160 1.9%
Concrete admixture 143 1.7%

0.7 0.6

1.9
1.7

0.7
0.2 0.3

U.S. Germany U.K. France Canada Italy(2002) (2002) (2002) (2002) (2002) (2002)

Coal mine filler
204 2.4%

Japan(2004)

12

Ground improvements 242 2.9%

Part 1 CCT Classifications
International Cooperation

Current State of International Cooperation
Concomitant with the progress of industrialization andurbanization, developing countries are now facing serious air andwater pollution issues. Coal is utilized to produce a significant
proportion of the energy consumed in developing countries,
particularly in Asia. As their economies have developed, it has
become an increasingly significant challenge for these countries todevelop and disseminate coal utilization technologies, along withbroad environmental conservation measures.
Unfortunately, insufficient capital, techniques and expertise limit
how much developing countries can improve environmental
conditions on their own. They require the assistance ofinternational organizations and of industrialized countries,
including Japan. Japan has therefore promoted international
cooperation with a focus on the Green Aid Plan (GAP) withcounterpart countries, including China, Indonesia, Thailand,
Malaysia, the Philippines, India and Vietnam.
In recent years, the global warming issue has attracted intenseinternational concern. Global warming is a serious problem for the
future of the earth and humankind, and is closely related to humaneconomic activity and its accompanying energy consumption.
Thus, it is important to address environmental needs during the
pursuit of economic development.
The Kyoto Protocol, adopted in Kyoto in December 1997 andwhich came into effect on February 16, 2005, includes the "Kyoto
Mechanisms," an important instrument for international

cooperation. One of the Kyoto Mechanisms, a market mechanism
known as the Clean Development Mechanism (CDM), is a newinternational cooperation system that aims to reduce greenhousegas emissions through cooperation between developed anddeveloping countries. To address global environmental issues thathave continued to worsen worldwide, developing countries areencouraged to maximize their self-help efforts toward improving theenvironment by stemming the increases in pollution and theworsening of global warming.
Japan has been encouraged to contribute to the economic growthand environmental improvement of developing countries throughthe active promotion of Japanese Clean Coal Technology (CCT) to
Asian countries including China, which is expected to show acontinued increase in coal demand. Japan also promotes
technological cooperation with Australia in order to make coal amore effective energy resource with even greater cost efficiency
and supply stability.

(1) Developing human resources
1) Training project on coal mining technology
Domestic mines have developed coal production and minesafety techniques with first-rate underground mining over a long
period of time. Making use of these techniques, Japan provides
technical cooperation to coal producing countries in the AsiaPacific region to improve their coal production and mine safety.
Japan also provides a human resource training project that
accepts engineers from abroad and sends Japanese engineers
to overseas coal-producing countries to ensure a stable supplyof imported coal. Over 300 manager-level or higher ranking coalengineers from China, Indonesia and Vietnam have participatedin the training program in Japan annually to receive face-to-facetechnical transfer sessions on business management, coalmining, mine safety and mechanical/electrical equipment at
Japan’s Kushiro mine and the Nagasaki Coal Mine Technology

Training Center.
For overseas training, Japan sends coal engineers to China toprovide seminar-style training, and sends coal engineers toIndonesia and Vietnam to provide direct guidance on-site at
local mines.

Transfer of Japan’s coal mining technology toAsia-Pacific region to ensure a stable supply of coal

Human Resources
Development

Training Project on
Coal Mining Technology

Transfer of environmental technology
through Green Aid Plan

Clean Coal Technology
Transfer Project

Training of coal engineers worldwide
within ODA system

JICA Training Project13

Clean Coal Technologies in Japan

3) Supporting JICA training projects
JCOAL supports or carries out coal-related projects and training
programs supported by the Japan International Corporation
Agency (JICA). JCOAL also provides domestic training programson coal mining and mine safety techniques to engineers fromIndonesia and Vietnam.

2) Promoting dissemination of clean coal technology
For the purpose of promoting the dissemination of clean coaltechnology, improving coal utilization technology and deepening
the understanding of these technologies, Japan promotes
technical transfers on coal utilization and quality management,
including pollution countermeasures to reduce SOx, NOx anddust emissions, as well as the promotion of high-efficiency
power generation to improve energy usage efficiencies, byinviting engineers from APEC countries to participate in training
programs in Japan.

(2) List of clean coal technologies and model projects relating to GAP
List of clean coal technologies and model projects relating to GAP
Project name

Project period

Target country

Site

Counterpart

Post-combustion cleaning
Simplified
desulfurization unit

Coke oven gas desulfurization unit

FY1993-FY1995

People’s Republic of China

Weifang Chemical Plant
Nanning Chemical Industrial Group
Changshou Chemical Works

The State Planning Commission/Ministry of Chemical Industry
The State Planning Commission/Ministry of Chemical Industry
The State Planning Commission/Ministry of Chemical Industry

FY1995-FY1997

ThailandThe Union Paper Public Co., Ltd.

Department of Industrial Works, Ministry of Industry

FY1998-FY2001

People’s Republic of China

Hunan Province Xiang Jiang Nitrogenous Fertllizer Industrial Co.,Ltd.

The State Development Planning Commission/State Administration of Petrochemical Industry/Hunan Provlncial Planning Commission

FY1999-FY2002

People’s Republic of China

Anyang Iron and Steel Group Co., Ltd.

The State Development Planning Commission/Henan Provlncial Planning Commission/The State Administration of Metallurgical Industry

Cleaning during combustion, improvement of combustion efficiency
Circulating fluidized
bed boiler

People’s Republic of China

Fangshan Garment Group Co.
Lingzi Coal Mine Zibo Mining Administration

The State Planning Commission/Beijing Planning Commission
The State Planning Commission/Ministry of Coal Industry

Philippines

Batangas Coal-fired Thermal Power Plant

Department of Energy

Indonesia

PT. Kertas Basuki Rachmat

Agency for the Assessment and Application of Technology (BPPT)

People’s Republic of China

Chaili Colliery, Zaozhuang Coal Mining Administration

The State Planning Commission/Ministry of Coal Industry

FY1996-FY1998

People’s Republic of China

Jinzhou Heat-power General Co.,Ltd.

The State Planning Commission/Planning Committee of Liaoning Provincs

FY1996-FY1999

People’s Republic of China

Zhejiang Huba Corporation

The State Planning Commission/Zhejiang Provincal Planning Commission

FY1997-FY1999

ThailandSaraburi factory of Indorama Chemicals (Thailand) Ltd.

Department of Industrial Works, Ministry of Industry

FY1997-FY2001

People’s Republic of China

Liaoyuan City Heating Power the Source of Energy Co.

The State Planning Commission/Jilin Provinclat Planning Commission

People’s Republic of China

Tangzhuang Mine of Linyi Coal Mine Administration

The State Planning Commission/Ministry of Coal Industry

Indonesia

Tanjung Enim Mine

Ministry of Mines and Energy

FY1996-FY1998

Indonesia

PT. Alas Wiratema Briket

Ministry of Mines and Energy

FY1997-FY1999

ThailandElectricity Generating Authority of Thailand Mae Moh Mine

Department of Industrial Works , Ministry of Industry

FY1998-FY2002

Philippines

Filipines Systems Inc.

Department of Energy

FY1994-FY1997

People’s Republic of China

Wangfenggang Coal Preparation Plant of Huainan Coal Mining Bureau
Preparation Plant of Dongtan Coal Mine of Yanzhou Coal Mining Bureau

The State Planning Commission/Ministry of Coal Industry
The State Planning Commission/Ministry of Coal Industry

People’s Republic of China

Beijing Yanshan Petrochemical Corp.

The State Planning Commission

FY1993-FY1995

FY1995-FY1997

Pre-combustion cleaning
Briquette production
unit

Water-saving coalpreparation system
Desulfurization-type CWM unit

FY1993-FY1995

FY1995-FY1998-

14

Part 2 CCT Overview
Technologies for Coal Resources Development

1A1. Coal Reserve Exploration Technology
Technology Overview

1. Background
Coal is an important energy resource, responsible
for producing 20% of the primary energy supply inJapan. However, 99% of the coal utilized is imported.
To promote the sustainable development of coalresources in coal-producing countries and regionswith a high potential for coal production, geologicalsurveys, information analysis and evaluations from avariety of perspectives are important to ensure astable energy supply. Coal reserve exploration
technologies have become more precise and theimaging has been improved to provide higher
resolution. For example, coal seams that occur undera high-density stratum can now be detected withhigher resolution imaging. Also, a technology thatallows direct estimation of ash and sulfur content incoal during geophysical logging has been studied. It
Image of high-resolution, high-efficiency survey systemis therefore important to establish a coal reserve
assessment system, based on drilling or otherexploration technologies, that will directly contributeto coal resource development and production plans,with a view to lessening the burden on both the local
and global environment.

2. Technology overview
Coal reserve assessment technologies being adopted for[2] As part of a joint study with the Vietnam National Coaloverseas coal-producing countries, (e.g. a joint coaland Minerals Group (VINACOMIN), deep sounding is being

resource evaluation survey in Indonesia and joint coalcarried out on the Quang Ninh coal basin in northern

exploration in Vietnam) are to be improved, in addition toVietnam for underground mining and coal development.

the promotion of environmental technologies for global[3] Through a joint project with Mongolia’s Ministry ofwarming prevention, including methane gas recovery in coal

Industry and Trade, coal resource exploration is currently

mines, carbon dioxide sequestration in coal seams and mine

being conducted in the Eastern Gobi, where the existence ofreclamations.

a potential coal supply is anticipated.

Resource exploration[1] Through a joint study with the Ministry of Energy andMineral Resources in Indonesia, GIS (Geographic Information
Systems)-related technologies have been introduced tosouth Sumatra to digitize coal resource data, and to build aresource information database to allow general coalresource assessments as well as the development of an
integrated software program.

15

Clean Coal Technologies in Japan

Coal resource evaluation system

Geological survey

Decision support system for coal development

Drilling survey in Indonesia

Electricity

Electricity
Steam

Factories
Fuel for power generation
Gas drainage
well prior to mining

Coal seam

Chemical plants

Steam

Power plants in factories

Communities

City gasGas drainage piping
during mining

MethanolGas drainage
well prior to mining

Methane gas

Coal seamWorking
face

Goaf

Coal seam

Coal seamCollection and utilization of methane gas from coal mines

16

Motor fuelPart 2 CCT Overview
Technologies for Coal Resources Development

1A2. Coal Production Technology
Technology Overview

seepage due to higher ground pressure. The mining
machinery is required to have maneuverability to respond tovariations in natural conditions. Utilizing larger-scale mining
machinery to increase the extraction capacity of theequipment is limited by space constraints.
For mining coal deposits near the ground surface, open-cut
mining is used to strip the overburden and extract the coal.
When coal deposits are steeply dipped or composed ofseveral coal seams, open-cut mining is used for extraction. In
this mining method, the overburden is piled in a place where it
will not interfere with the mining work, and a pit is formed in
the ground surface during mining. Horizontal or slightly dipped
coal deposits are mined by the strip mining (side casting)method, in which the overburden is temporarily piled justbeside the mining site and returned to the original site after
the coal has been extracted.

Coal occurs in slightly or steeply dipped beds, or in the formof discontinuous lenses underground. The depth, number andthickness of coal seams vary by region. Coal minedevelopment requires consideration of these geologicalconditions and the state of ground surfaces. Specifically, thequality of coal, the depth, thickness and dip of coal seams,
the presence of faults and folds, and the properties of coalbearing strata substantially affect the productivity and theresource collection rate. The mining method to be used may
also vary due to these conditions. Underground mining
requires the drilling of shafts down to an underground coalseam to extract coal. The shafts may also be used totransport equipment and workers, for ventilation anddrainage, or for prospecting for coal. As mining develops, thedigging area becomes deeper, raising the issues ofmaintaining the mining space, gas emissions, and water
1. Backgroundproductivity while addressing the challenges faced by coalproducing countries. These efforts have led to theestablishment of stable coal production systems and improved
production capability, thus contributing to a stable supply of coalfor Japan. Japan has also extended assistance to coalproducing developing countries for the sound development oflocal coal industries through joint research with localorganizations, aimed at improving coal production technology.

Coal-producing countries in the Asia-Pacific region are facedwith coal mining challenges, such as mining under deeper andmore complex geological conditions. To cope with thesechallenges, while improving safety and productivity, newtechnical measures are required. NEDO and JCOAL have,therefore, carried out domestic and international research anddevelopment on coal production based on technologies
introduced and developed in Japan to improve mine safety and2. Technologies to be developed
To address the challenges faced by coal-producing countries
in the Asia-Pacific region, such as mining under complex
geological conditions while ensuring safety, improved
productivity, and a stable coal supply, novel technicalmeasures are required.

Overview of typical open-cut mining
Stripped
overburden
Coal seam(1) Open-cut mining- Draglines- Power shovels and dump trucks- Overview of open-cast mining- Side-cast O/C
Side-cast strip mining(2) Underground mining- Longwall mining- High-power coal mining machines- Highwall mining (auger mining)

Draglines

Underground mining (headframe)

Power shovels & dump trucks
17

Clean Coal Technologies in Japan

Development of a high-power coal mining machine
In order to achieve higher production efficiency in mining hard and thick coal seams, a new high-power multi-motor
coal mining machine was demonstrated at a mine in Australia.

Longwall mining (SD Mining) drum shearer and shield support

High-power coal mining machine (following control function)

Development of a high-power excavator
To improve the efficiency of hard-rock tunnel boring, ahigh-power rock excavator equipped with rock bolts has
been developed.

Highwall mining (steep incline auger mining system)

Drifting road header MRH-S220

Development of high-speed manned cars
In underground coal mining, as drifting progresses to include deeper working faces, measures are needed to ensure
the necessary working time in the faces. To increase the efficiency of transportation and shorten the transportation time,
high-speed manned cars with a maximum speed of 50 km/hr have been developed.

High-speed manned cars (former Taiheiyo coal mine)

High-speed manned cars (former Ikeshima coal mine)

18

Part 2 CCT Overview
Technologies for Coal Resources Development

1A3. Mine Safety Technology
Technology Overview

1. Background
According to the Mine Safety Technology Development andtopics. Based on the results of this development, international

Long-term Technical Transfer Plan, the development of mine

joint research and technical cooperation/transfers have madesafety technology has been promoted with a focus on priority

considerable progress.

2. Technologies to be developed(1) Applying mine safety technology to overseas mines

purpose of developing systems, a site demonstration on long

Japan applies its mine safety technology to model coal mines

bolts was carried out at the Kushiro mine in Hokkaido. A

in coal-producing developing countries, thereby reducing

series of basic site tests were also conducted at the samemining disasters, improving mine safety and promoting stablemine to collect measurement data on microtremors, roof/crack

coal production.

displacements, rock stress, acoustic characteristics and on[1] In China, Japanese gas explosion disaster prevention

elastic wave through the use of impact tests. Another study ontechniques have been introduced to the Zhang-ji mine of theroof fall prevention is underway to develop a system to identify

Huainan Mining (Group) Co. Ltd. in Anhui Province throughroof conditions by analyzing machinery data during the drilling

the Central Coal Mining Research Institute. Specifically, theof rock bolt holes.

following four improvements were made: installation of a gas[2] With a view to developing comprehensive undergroundmonitoring system, enhancement of gas drainage efficiency

gas management technology, numerical analysis software,with directionally controlled gas drainage boring technology,

MGF-3D, which uses the stress variations that occur as

introduction of underground ventilation analysis software anddigging proceeds, is being improved and subjected to model

the installation of an underground radio system.

analysis. The software also has a gas-liquid, two-phase[2] In Indonesia, Japanese spontaneous combustion disaster

analysis function to improve analytical accuracy.

prevention techniques have been introduced at the PTBA

[3] An advanced monitoring and communications system for

Ombilin mine through the Mineral and Coal Technology

underground mine safety and stable production has been

Research and Development Center (TekMIRA), including CO

developed through joint research conducted with theand temperature monitoring technology, gas analysis,

Commonwealthunderground ventilation network analysis and wall grouting.

Organisation (CSIRO). The system has now reached the[3] In Vietnam, Japanese mine water inflow disasterstage of being applied to mine sites. This joint research also

prevention technologies have been introduced to Mao Kheaims to build a basic system for risk information management

coal mine and other sites through the National Coal andthat allows the real-time evaluation of different disaster risk

Minerals Group (VINACOMIN), including hydrological data

factors (relating to work, environment, devices andcollection and analysis, underground water flow analysis

machinery). As an early detection technique, an odor sensor

using hydrogeological models, advanced boring technology

based on worldwide standards is now being studied in a joint

for water exploration and drainage, and a flow rate

research project with the Safety in Mines, Testing andmeasuring/pumping system.

Research Station (SIMTARS). At the Kushiro mine, a "manScientificandIndustrial

Research

location system" and an underground communications system(2) Joint research on mine safety technology

were tested during an on-site demonstration.

Through domestic development and international joint
research with coal-producing developed countries, Japanpromotes the development and sophistication of mine safety
technology. This joint research will help further raise minesafety technology standards in both developing anddeveloped coal-producing countries.
[1] Techniques to prevent roof fall accidents in roadways or atworking faces have been developed, including roof fall risk
prediction and roof fall prevention systems. These techniques
are subjected to evaluation and applied to mine sites. For the19

Clean Coal Technologies in Japan

Centralized monitoring and management technology
All underground mine safety information, including different measurement data items and the status of machine operations (both received
and sent data), is controlled as a single unit by a computer system in a centralized monitoring and control room located on the surface.

Centralized monitoring and control room

Centralized monitoring computers

Roadway support technique (rock bolting)A rock bolting roadway support technique is based on rock mass evaluations and measurements to overcome Japan’s soft soil conditions.

Geostructure data logging
Technology to determine roof conditions by compiling machinery data
during the drilling of bolt holes

Data transmitting roof
displacement gauge
Bolt-supported roadway

Drilling

Gas drainage technology
Gas drainage from coal seams and gobs is performed to prevent the emission of explosive methane gas.
The drainage is safely controlled in terms of volume and concentration using the centralized monitoring system.

Gas drainage boringGas drainage holeGas drainage monitoring sensors

20

Gas drainage monitoring computerPart 2 CCT Overview
Technologies for Coal Resources Development

1A4. Environment-friendly Resource Development Technology
Technology Overview

1. Background
Through on-site demonstrations of carbon dioxide fixation in coal

recovery through the underground gasification of coal resources,

seams, the reservoir characteristics of coal seams in Japan werewhich may offer significant environmental benefits. The

identified in order to collect basic data on carbon dioxide. In

development and commercialization of CDM projects were also

addition to conventional coal preparation and reforming, andaddressed.

CMM collection and utilization, efforts were made to study energy
2. Technologies to be developed(1) Coal preparation and reforming technology[1] Coal preparation technology is used in Indonesia toefficiently sort raw coal with different properties in order toensure stable product quality and reduce the environmental
burden. Japan manufactured part of the equipment necessary
for improving existing coal preparation plants in Indonesia. To
introduce jigging feedback control using on-line ash monitors
to the coal preparation process in Indonesia, Japan
formulated a control rule on a trial basis from the results of a
feedback control applicability test.
[2] To promote the effective use of low-rank coal, a reforming

Flotation machine

plant using the upgrading brown coal (UBC) process (rawcoal processing capacity: 5 tons/day) was subjected to test
operations in Indonesia, where, compared to other countries,
a relatively higher percentage of brown coal reserves exist. In
the UBC process, low-rank coal is dehydrated in an oil slurry
to stabilize it and make it water-repellent under moderateconditions. In the test plant, various types of Indonesian coalwith different properties were tested. The data obtained wasused for evaluation tests on spontaneous combustion,
combustibility and other properties. It was ultimately
confirmed that the reformed coal had handling properties andcombustibility equal to or greater than those of bituminous

Heavy media cyclone

coal.

Effluent thickener
21

Clean Coal Technologies in Japan(2) Global environmental technology[1] To suppress the release of carbon dioxide (CO2) to theCO2 is injected at the maximum allowable pressure that willatmosphere, a preliminary test on a new technology to

not induce the crushing of the coal seam. More than 900

sequester CO2 in deep coal seams has been conducted intons of CO2 are planned to be injected. Hydraulic fracturing

the southern part of Yubari City in Hokkaido. The site

tests of the coal seams are due to be conducted to improve

injection test will be conducted through FY2006, aiming to

gas injections and coal productivity.

successfully sequester CO2 in PW-1, a methane gas[2] A site test of a technique for the stable collection andobservation well. Since the injection well IW-1, drilled inutilization of methane gas escaping from coal mines was

FY2003, is expected to have lower permeability due to CO2

carried out at an abandoned domestic mine in Hokkaido.

absorption and swelling, N2 gas is injected to reduce CO2
absorption and subsequently improve the permeability. N2
gas is also used as a preliminary gas for CO2 sequestration.

Current status

Capture and utilization

MethaneTotal methane emissions from coal mines
worldwide are 25 million tons per year, of
which 6% is captured and utilized.
(Source: IEA- Global methane and the coal industry)

Boiler andgenerator
Exhaustfan

Exhaustfan
Gas tank

Main shaft

MethaneExhaustshaft

Coal seam

MethaneGas released tothe surface

Coal seam

MethaneConceptual drawing of coal mine methane gas capture and utilization

22

Gas
releasedfromunderground

Exhaustshaft

MethanePart 2 CCT Overview
Coal-fired Power Generation Technologies (Combustion Technologies)

Efficiency Pulverized Coal-fired Power Generation Technology
2A1. High(Ultra Super Critical Steam Condition)
Technology Overview

1. Pulverized coal-fired power generation system
The pulverized coal-fired power generation system (Fig. 1) is widelyused as an established, highly reliable technology. In 2000,
600/610oC USC (Ultra Super Critical Steam Condition) systems were
installed at J-POWER’s Tachibanawan Thermal Power Station’s No. 1
and No. 2 plants (1050 MW each). J-POWER’s Isogo New Unit No. 1,
which was put into service in 2002, uses the same system with purevoltage regulation at the main steam temperature of 600oC and thereheat steam temperature of 610oC. Further challenges will be to use
more types of coal, increase generation efficiency, improve
environmental measures and enhance load operability.

Steam

Pulverized
coal

Air

Coal pulverizer
Steam conditions

Pressure (kg/cm2)

Temperature (oC)

169
246
325

566
538
596

Subcritical
Supercritical
Ultra-supercritical

566 C

condition of 24.5 MPa x 600 oC/600 oC in 1998. Furthermore,
J-POWER’s Tachibanawan No. 1 and No. 2 plants (1050 MW)
adopted the steam condition of 25.0 MPa x 600oC/610oC in 2000.
Figure 3 shows an example of the relationship between thesteam condition and the efficiency of a supercritical pressure
plant.
Responding to the trend of increasing steam temperatures,
power companies, steel manufacturers, and boiler manufacturers
are promoting the development and practical application of highstrength materials with superior high-temperature corrosion
resistance, steam-oxidation resistance, and workability.
High-temperature materials for use at 650oC have already been
introduced into practical application, with work proceeding todevelop materials for use at 700oC.

610OC
Power generation efficiency (%LHV)

593OC

500

24.5MPa

31.0MPa30

24.1MPa
16.6MPa

400

20
Steam pressure(Right scale)

300

200
1910

Steam pressure MPa

Steam temperature OC

600

Steam temperature(Left scale)

10

0
1920

1930

1940

1950

1960

1970

Capacitor

Fig. 1 Pulverized coal-fired power generation system (Rankine cycle)

600OC
538OC

Feed water pump

Coal ash

2. Efficiency increase
Increasing the thermal efficiency of power generation plants is an
important issue not only to decrease the power generation costs
from an economic standpoint, but also for suppressing CO2
emissions. In particular, steam temperatures at coal-fired power
plants, which are currently the most prevalent among large
thermal power plants, have increased. Figure 2 shows the trendof steam condition in recent years.
In 1989, Chubu Electric Power Co., Inc.’s Kawagoe No. 1 plant(700 MW) adopted the steam condition of 316 kg/cm2g (31.0
MPa) x 566oC/566oC. In 1993, Chubu’s Hekinan No. 3 plant (700MW) adopted the steam condition of 246 kg/cm2g (24.1 MPa) x
538oC/593oC, marking the highest reheated steam temperature in
Japan. Subsequently, The Chugoku Electric Power Co., Inc.’s
Misumi No. 1 plant (1000 MW) and Tohoku Electric Power Co.,
Inc.’s Haramachi No. 2 plant (1000 MW) adopted the steam

O

G

Steam turbine

Flue gas

Pulverizedcoal boiler

1980

1990 2000 2005

46

0

45

−1

44

CO2 reduction rate ー2

43

ー3

Efficiency

CO2 reduction rate (%)

Coal

Generator

ー4

42

ー5

41

Main steam temperature (oC) 538

538

Reheat steam temperature (oC) 566（Base）

593

566

600

625

593

600

625

Steam temperature (oC)Fig. 3 Power generation efficiency and CO2 reduction rate
for various steam conditions

Fig. 2 Changes in steam condition over time23

Clean Coal Technologies in Japan

3. Combustion technology
Various combustion techniques have been developed and putclassified according to the suppression of NOx generation at the

into practical application in response to the need to satisfy

burner and the intrafurnace denitration, using all the zones in theJapan’s strict environmental regulations, and to achieve high-furnace.

efficiency combustion. The NOx emission level and the dust

(1) Low NOx pulverized coal burner

generated during the combustion of coal in Japan is at the

The latest burners have both improved ignitability and intraflameworld’s lowest level, even at boiler exit. The ultimate emission

denitration, although the structure varies by boiler manufacturer.

level owes to the flue gas treatment administered at theThese burners basically use the separation of dense and leandownstream side of the boiler. Since NOx and dust emissions

pulverized coal streams and a multilayer charge of combustion

are very closely related, low NOx combustion technology isair. Figures 4 to 7 show the burner structures of several

addressed here. Low NOx combustion technology is roughly

Japanese manufacturers.

Dense
flame

Enhancing intraflame denitration combustion through outer-periphery stable ignition
Secondary air Tertiary air
Tertiary air swirling vane

Tertiary air
Secondary air

Lean
flame

Distributor vane
Oil burner
Reducing flame

Dense flame
Lean flame
Dense flame

Primary air + Pulverized coalPrimary throat
Secondary throat

Dense flame
Lean flame
Dense flame

Rib

Primary flame holding plate
Secondary flame holding plate

Fig. 5 CC-type pulverized coal-fired burner:
Kawasaki Heavy Industries, Ltd.

Fig. 4 Pulverized coal-fired A-PM burner: Mitsubishi Heavy Industries, Ltd.
Burner inner cylinder
Primary air + Pulverized coal

Burner outer cylinder

Secondary air inner vane
Secondary air vane
Flow detector
Throat ring

Tertiary air damper
Oil burnerPrimary air
Inner periphery(Pulverized coal + Air) secondary air

Primary air + Pulverized coal
Tertiary air

Volatile matter combustion zone
Reducing agent generation zone

Furnace wall
tube
Outer secondary air

Oil burner support
Secondary air vane driver
Secondary air inner vane driver

Outer peripherysecondary air

Secondary air

NOx decomposition zone
Char combustion enhancing zone

Fig. 7 Pulverized coal-fired NR burner: Babcock-Hitachi K.K.

Inner secondary air

Fig. 6 DF inner vane pulverized coal-fired burner:
Ishikawajima-Harima Heavy Industries Co., Ltd.

Furnace exit(2) Intrafurnace denitration

Combustion completion zone

Intrafurnace denitration is conducted by reducing the NOx
generated in the main burner zone, using the residual

Additional airhydrocarbons or the hydrocarbons generated from a small

NOx reducing zone
containing unburned fuelamount of fuel oil fed from the top of the main burner. The
intrafurnace denitration is performed in two stages. Figure 8 is aconceptual drawing of intrafurnace denitration.

Over fire air
Main burner
combustion zone

In the first stage, hydrocarbons reduce NOx levels. In the second
Main burnerstage, the unburned matter is completely combusted by theadditionally injected air.

Intrafurnace denitration
Fig. 8 Conceptual drawing of intrafurnace denitration
24

Part 2 CCT Overview
Coal-fired Power Generation Technologies (Combustion Technologies)

2A2. Circulating Fluidized-bed Combustion Technology (CFBC)
Technology Overview

1. Features
The features of circulating fluidized-bed boilers are described

thermal NOx emissions as the generation of NOx is dependent

below.

upon the combustion temperature. In addition, the operation of1) Compatibility with wide range of fuels

circulating fluidized-bed boilers involves a two-stage combustion

Conventional boilers for power generation can use only fossil

process: the reducing combustion at the fluidized-bed section,

fuels, such as high-grade coal, oil, and gas. The CFBC is also

and the oxidizing combustion at the freeboard section. Next, thecapable of using low-grade coal, biomass, sludge, waste plastics,

unburned carbon is collected by a high-temperature cyclone

and waste tires as fuel.

located at the boiler exit to recycle to the boiler, thus increasing

2) Low polluting

the denitration efficiency.

NOx and SOx emissions are significantly decreased without

3) High combustion efficiency

special environmental modifications. In the case of fluidized-bed

Improved combustion efficiency is attained through the use of aboilers, desulfurization is carried out intrafurnace, using mainly

circulating fluidization-mode combustion mechanism.

limestone as the fluidizing material. For denitration, PC boilers4) Space-saving, ease of maintenance

operate at combustion temperatures from 1,400oC to 1,500oC,

Space saving is attained because there is no need for separate

whereas circulating fluidized-bed boilers operate at lower

desulfurization, denitration, and fine-fuel crushing units. Accordingly,

temperatures, ranging from 850oC to 900oC, thereby suppressing

trouble-spots are minimized, and maintenance is simplified.

2. Technology overview
Figure 1 shows a typical CFBC process flow.

Hot cyclone

CFBC boiler

Generated steam
Coal Limestone

Flue gas
Boiler feed water heater

Boiler feed water

Circulating
fluidized-bed
furnaceSecondary air
Primary air

Cyclone

Air pre-heater

Electric
precipitator
Heat
recoverysectionID fanStack

Ash storage tankFig. 1 Process flow of circulating fluidized-bed boiler

Figure 2 provides a rough overview of CFBC. Generally, CFBC

Fig. 2 Schematic drawing of CFBC

consists of a boiler and a high-temperature cyclone. The intra-furnace
gas velocity is as high as 4 to 8 m/s. A coarse fluidizing medium anda pre-heater for the fluidizing air and combustion air, and a boiler feedchar in the flue gas are collected by the high-temperature cyclone

water heater, are installed. Most of the boiler technologies are

and recycled to the boiler. Recycling maintains the bed height andmanufactured overseas, mainly from Foster Wheeler, Lurgi,

increases the denitration efficiency. To increase the thermal efficiency,

Steinmuller, ALSTOM, and Babcock & Wilcox.

3. Study site and application field
Photo 1 shows an overview of a CFBC boiler facility. The CFBC gainedrefinery (300 t/hr), and Ube Industries, Ltd.’s Isa

popularity mainly as a coal-fired boiler. Recently, however, CFBC

plant (210 t/hr). An example of an RDF-fired

boilers using RDF and wood-based biomass as the fuel have drawn

boiler is Sanix Inc.’s Tomakomai plant. The

attention. Typical applications of coal-fired biogas are the Kuraray Co.,

biomass fuel is mixed with coal and combusted,Ltd.’s Tamashima plant (70 t/hr), Idemitsu Kosan Co., Ltd.’s Chiba oil

thereby decreasing CO2 emissions.

4. Study period
Most of the circulating, atmospheric-pressure fluidized-bed boiler(CFBC) technologies were introduced into Japan from abroad,
beginning around 1986.

Photo 1 CFBC appearance

5. Progress and development results
CFBC technology was introduced from abroad and used in coal-

Outstanding

fired boilers. It is used by power producers, iron makers, paper

investigation of and efforts to reduce the initial costs and to

CFBC-related

issuesincludethe

producers, and in other sectors. Plans exist to distribute CFBC

improve the power generation efficiency for boilers using fuelssuch as RDF, industrial waste, and wood-based biomass.

technology to China under the Green Aid Plan (GAP).
25

furtherClean Coal Technologies in Japan

2A3. Internal Circulating Fluidized-bed Combustion Technology (ICFBC)
Research and development: Japan Coal Energy Center; Ebara Corporation; Idemitsu Kosan Co., Ltd.
Project type: Coal Production and Utilization Technology Promotion Grant
Period: 1987-1993

Technology Overview

1. Features
The basic characteristics of ICFBC are described below:

3) Low polluting

I. Uniform temperature in fluidized-bed, owing to the swirling flow

NOx and SOx emissions are significantly decreased withoutof sand.

special environmental modifications. For the fluidized-bed boiler,

II. Easy discharge of non-combustibles, also owing to vigorous

desulfurization takes place mainly in the furnace. However,

movement of sand.

ICFBC does not have a heat transfer tube in the fluidizing

III. Ability to control the temperature of the fluidized-bed bysection, so the boiler does not cause wear on the heat transfer

adjusting the heat recovery from the fluidized-bed.

tube in the bed. Because of this, silica sand can be used as theBased on these, ICFBC has the following features:

fluidizing material for ICFBC, instead of soft limestone. As a1) Adoption of various fuels

result, ICFBC needs minimum quantities of limestone as an

Similar to CFBC, ICFBC is capable of using not only fossil fuels,

intrafurnace desulfurization agent. The desulfurization efficiency

such as high-grade coal, oil, and gas, but also low-grade coal,of ICFBC approaches 90% at a Ca/S molar ratio of around two,biomass, sludge, waste plastics, and waste tires.

though the efficiency depends on the coal grade, the amount of2) Control of bed temperature

limestone applied, and the temperature of the fluidized bed.

Since the overall heat transfer coefficient varies almost linearly

Denitration is conducted through a two-stage combustion

with the variations in the air-flow rate in the heat recovery

process: the reducing combustion at the fluidized-bed section,chamber, the quantity of recovered heat is easily regulated

and the oxidizing combustion at the freeboard section. The

through the control of the air-flow rate. In addition, control of theunburned carbon from the boiler is collected by the high-quantity of recovered heat regulates the temperature of thetemperature cyclone installed at the exit of the boiler. The

fluidized-bed. Since the control of the recovered heat iscollected, unburned carbon is recycled to the boiler to increase

performed solely by varying the air-flow rate, adjusting the load isthe denitration efficiency.

very simple, which is a strong point of ICFBC.

4) Space-saving, ease of maintenance
Similar to CFBC facilities, ICFBC facilities do not need separate
units for desulfurization, denitration, and fine-fuel crushing.
Therefore, ICFBC facilities are space saving and easier tomaintain because trouble-spots are minimized.

2. Technology overview
Figure 1 shows an overview of ICFBC. The technology uses silica
sand as the fluidizing material. The fluidized-bed is divided into

Freeboardthe main combustion chamber and the heat recovery chamber byPrimary
combustion
chambera tilted partition to create a swirling flow inside the main
combustion chamber and a circulation flow between the main
combustion chamber and the heat recovery chamber. A
circulation flow is created to return the unburned char andunreacted limestone from the cyclone at the exit of the boiler toHeatrecoverychamberthe boiler.
1) The swirling flow in the main combustion chamber is createdby dividing the window box in the main combustion chamber into
three sections, and by forming a weak fluidized-bed (moving bed)at the center section, introducing a small amount of air whileforming strong fluidized-beds at both end-sections andintroducing large volumes of air. As a result, the center section of
the main combustion chamber forms a slow downward moving
bed, and the fluidizing material, which is vigorously blown up fromboth ends, settles at the center section, and then ascends at bothFig. 1 Overview of ICFBC

end-sections, thereby creating the swirling flow.
26

Part 2 CCT Overview
Coal-fired Power Generation Technologies (Combustion Technologies)

2) The circulation flow between the main combustion chamber

3. Study sites and application fields

and the heat recovery chamber is created by the movement

Examples of locations and companies using coal-fired ICFBC

described hereafter: A portion of the fluidizing material, which isinclude: Chingtao, EBARA CORP. (10 t/hr); Jiangsan in China (35vigorously blown up at both end-sections in the main combustiont/hr); and Nakoso, Nippon Paper Industries Co. (104 t/hr).

chamber, turns the flow direction toward the heat recovery

Examples of locations and companies using ICFBC using

chamber at a position above the tilted partition. The heat recovery

industrial waste as the fuel include: Motomachi, Toyota Motorchamber forms a weak fluidized-bed (downward moving bed)

Corp. (70 t/hr); Tochigi, Bridgestone Corp. (27 t/hr); Fuji,

through the circulation bed air injected from under the chamber.

Daishowa Paper Mfg. Co., Ltd. (62 t/hr); Amaki, Bridgestone

Accordingly, the fluidizing material circulates from the main

Corp. (7.2 t/hr); and Akita, Tohoku Paper Mfg. Co., Ltd. (61.6 t/hr).

combustion chamber to the heat recovery chamber, and again to

In Shizuoka, Chugai Pharmaceutical Co., Ltd. is operating an

the main combustion chamber from the lower part of the heatRDF-fueled ICFBC site (3.7 t/hr).

recovery chamber. Since the heat recovery chamber is equippedwith heat transfer tubes, the circulation flow recovers the thermalenergy in the main combustion chamber.

4. Development period

3) The circulation flow from the cyclone at the exit of the boiler

ICFBC was developed in 1987, and was further developed

passes through the cyclone or other means to collect unburnedand validated as a low-polluting, small-scale, and high-char, emitted fluidizing material and unreacted limestone, andefficiency fluidized-bed boiler for multiple coal grades in thethen returns to the main combustion chamber or the heat"Study of Fluidized-bed Combustion Technology," conducted

recovery chamber, using a screw conveyer, pneumatic conveyer,by the Coal Utilization Technology Promotion Grant project ofor other means. The circulation flow is extremely effective in

the Ministry of International Trade and Industry over theincreasing the combustion efficiency, decreasing the generation

course of six years from 1988 to 1993.

of NOx, and improving the desulfurization efficiency.

5. Progress and development results
Although ICFBC was initially developed to use high calorific value
industrial waste, it was improved to use solid fuel with a highcalorific value and has been developed as a coal-fired boiler. A
boiler plant was constructed in China, a country with abundantcoal reserves, in the city of Chingtao, a manufacturing base.
Recently in Japan, wood-based biomass has been used as a fuelin some cases. However, a further reduction in up-front
investment costs is required to disseminate the technology toSoutheast Asia and other areas rich in biomass resources andlow-grade coal.
Photo 1 ICFBC site

Steam
Boilerdrum

Dry coal

Stack
Dry
feed
systemCoalbunkerLimestone
Pulverized coal
SlurryfeedsystemAir compressor

CWP
mixingsystemAir
heaterDepressurizing
unit

PICFB

Crusher

Hot gasfilter

IDF
Steam

Bag
filterWaste heatboiler(Gas cooler)

CWP pump

Ash Coolingpipe

Pressure vessel

Boiler water
circulationpump
Hot blast generator

Deashing
systemPneumatic ash transport system

Fig. 2 Flowchart of PICFBC model test plant
27

AshClean Coal Technologies in Japan

2A4. Pressurized Internal Circulating Fluidized-bed Combustion Technology (PICFBC)
Research and development: Japan Coal Energy Center; Ebara Corporation
Project type: Coal Production and Utilization Technology Promotion Grant
Period: 1992-1998

Technology Overview

1. Overview
PICFBC’s basic technology is the technology of the internal
circulating fluidized-bed combustion boiler (ICFBC) described in

the preceding section. The PICFBC mounts ICFBC in apressurized vessel.

2. Features
The pressurized internal circulating fluidized-bed boiler (PICFBC)
applies the circulation flow technology of the previously-described
ICFBC. Accordingly, the load is controllable without varying theheight of the fluidized-bed. In addition, cooling of the combustion
gas is avoided because the intra-bed heat transfer tubes are notexposed on the bed during the load controlling action, which
minimizes the generation of CO2 and eases the maintaining
temperature at the inlet of the gas turbine. Since the wear
problems of the heat transfer tube in the bed are decreased,

silica sand can be used as the fluidizing material, and the amountof limestone can be minimized to a level necessary for the intrafurnace desulfurization, thus suppressing the generation of ash.
Furthermore, the main combustion chamber has no intra-bed
heat transfer tube so that the problem of interference of the intrabed heat transfer tube against the movement of the particles
does not occur, which prevents the generation of agglomeration,
the solidification of a melted medium.

3. Technology overview

Fig. 1
Schematic drawing of PICFBC

and the circulation flow is created between the main combustion
chamber and the heat recovery chamber.
Figure 2, (p. 27), shows a basic system flowchart of a pilot plant
test in Sodegaura plant. The coal feed unit has two lines: the lockhopper system, which feeds lump coal, and the CWP (Coal Water
Paste) system, which feeds coal as slurry mixed with water. The
flue gas dust is removed by a ceramic high-temperature bag filter.
The lock hopper system technology is applied to develop thepressurized two-stage gasification technology.

Figure 1 shows a schematic drawing
of a PICFBC. The cylindrical pressure
vessel contains a cylindrical ICFBC.
Similar to ICFBC, silica sand is usedas the fluidizing material. The
fluidized-bed is divided into the main
combustion chamber and the heatrecovery chamber by the tilted
partition. The swirling flow is createdin the main combustion chamber,

4. Study sites and application fields
The PICFBC pilot plant test was carried out at a site next to theIdemitsu Kosan Co., Ltd.’s Coal Research Laboratory (Nakasode,
Sodegaura City, Chiba). Potential applications include the steam
turbine generator, using the generated steam, and the gas
turbine generator, using the combustion flue gas. IGCC at coalfired thermal power plants, therefore, are potential candidates forthe technology. Photo 1 shows a PICFB hot model installation of
4 MWth. Photo 2 shows an overview of a pressurized two-stage
gasification plant (30 t/d of waste plastics throughput). The
pressurized two-stage gasification technology can be utilized tosynthesize ammonia from coal, as well as to produce hydrogenfor fuel cell power generation. The pressurized two-stage

gasification technology has been in operation as a commercial
plant (195 t/d of waste plastics throughput) at Showa Denko
K.K.’s Kawasaki plant since 2003.

Photo 1PICFBC facility

Photo 2Pressurized, two-stage gasification plant

5. Period of development
The ICFBC pilot plant test was carried out from 1992 to 1997,
jointly conducted with the Center for Coal Utilization, Japan (nowknown as JCOAL), as a Coal Utilization Technology Promotion
Grant Project of the Ministry of Economy, Trade and Industry(formerly the Ministry of International Trade and Industry). The

test operation began in December 1996. The pressurized, twostage gasification technology was developed jointly with Ube
Industries, Ltd. Demonstrative operation of the plant (30 t/d ofwaste plastics throughput) began in January 2000, andcommercial operation commenced in January 2001.

6. Progress and study subjects
As a coal-fired PICFBC, the study progressed to the pilot plant
test at Sodegaura. The technology, however, was developed to apressurized two-stage gasification technology in which a thermalload and a lock hopper system in the pressurized fluidized-bed

have been applied. The issues of the pressurized system include
the improvement of the reliability of the lock hopper system in thefuel charge line as well as measures to prevent low temperature
corrosion.
28

Part 2 CCT Overview
Coal-fired Power Generation Technologies (Combustion Technologies)

2A5. Coal Partial Combustor Technology (CPC)
Research and development: Japan Coal Energy Center; Kawasaki Heavy Industries, Ltd.;JFE Steel Corp.; Chubu Electric Power Co., Inc.; and J-POWER
Project type: Coal Production and Utilization Technology Promotion Grant
Period: 1978-1986 (9 years)

Technology Overview

1. Background and technology overview
Owing to the abundant reserves and wide distribution ofhigh speed into a swirling melting furnace in a tangential

producing countries, the supply of coal is highly stable, and coaldirection, thus partially combusting (gasification) the coal underis well positioned as an important energy source for the future.

the conditions of a high-temperature, heavy load, and strong

However, compared with other fuels, such as oil and gas, coal

reducing atmosphere. After most of the ash in the coal is melted

contains large amounts of ash and nitrogen, which poses manyand separated for removal, the produced fuel gas is subjected toutilization issues, including equipment problems caused by ash,secondary combustion. CPC is a technology of coal gasificationand significant increases in NOx emissions. Furthermore, global

combustion in a boiler or a gas turbine to utilize coal highly-

warming has become an international concern in recent years,

efficiently and in an environmentally compatible manner. Theremaking it an urgent requirement to develop technology to reduce

are two variations of CPC technology: one utilizing atmospheric

CO2 emissions, one of the main causes of global warming. Sincepressure to produce atmospheric pressure clean gas with low

coal generates a large volume of CO2 per calorific value, there iscalorific value, and the other under a further pressurized

a need worldwide to develop technology to use coal in a highly-

environment to produce highly-efficient power generation in

efficient, environmentally compatible way. A Coal Partial

combination with a gas turbine.

Combustor (CPC) is a furnace where coal and air are injected at

2. Atmospheric pressure coal partial combustor technology
Slag-tap boilers aim to reduce the volume and detoxify the ash
Pre-heating burnerdischarged from the boiler and to use difficult-to-combust coal.
They have been constructed and have been operated in a large

Preliminary

number of Western countries. The conventional slag-top boiler

combustor

BaffleSecondary
combustor

has the advantages of high combustion efficiency and therecovery of ash as nontoxic molten slag. However, the method
Combustionair

has the drawback of significant NOx emissions caused by hightemperature combustion.

High-temperature
combustion gas

Responding to this issue, our technology development focused
Pulverized
coal

on the development of a coal partial-combustor system aiming tosimultaneously remove the ash from coal and limit NOx
emissions. The developed system has the CPC directly mounted
to the side wall of the boiler. The combustible gas generated in
the CPC is directly injected to the boiler furnace, where the gas iscompletely combusted with injected air.
As small to medium coal-fired boilers, CPC can significantly

Molten slag

reduce NOx emissions while maintaining the compactness of theboiler on a scale similar to that of an-oil fired boiler. It can recoverFig. 1 Schematic drawing of an atmospheric pressure coal partial
combustor (CPC) boiler

all the coal ash as molten slag. Figure 1 shows a schematic
drawing of a atmospheric pressure CPC boiler.

29

Clean Coal Technologies in Japan

3. Pressurized coal partial combustor technology
On the basis of the results of the atmospheric pressure CPC

Figure 2 below shows a basic flow chart of a pressurized CPC pilot

development, the development of pressurized CPC technology

plant having 25 t/d of coal gasification capacity (operating at 21%

began, with the objective of developing a high-efficiency power

oxygen). The pilot plant ran the coal gas generation test using CPC

generation system by pressurizing CPC and combining it with aunder a pressure of 20 ata, which can be applied to a gas turbine.

gas turbine.

The test proved the effectiveness of the pressurized CPC.

Pressurized pulverized coal feeder

Kerosene tankGas cooler

Ceramic filter

Gas incinerator
Pulverized coalproduction unit

Denitration unit
Flux feeder

Liquid oxygen tankChar hopper

CoolerPrimary air compressor
Slag tankChar feeder

Air compressor

Desulfurization unit

Liquid nitrogen tankFig. 2 Basic flow chart of a pressurized CPC pilot plant

4. Issues and feasibility of practical application
Atmospheric pressure CPC technology has already been brought
into practical application as a low NOx emission technology inswirling melting furnaces of municipal waste gasification melting
furnaces and in very low NOx boilers for heavy oil combustion.
Atmospheric pressure CPC technology is also being used in thedevelopment of a coal-ash-melting, low NOx boiler. A pilot plant
test for the pressurized CPC technology is nearing completion,and the technology is in the research and development stage inthe private sector, with the aim of bringing it to practical use.
These basic technologies have also been integrated with thedevelopment of biomass gasification gas turbine power generation
technology.

Photo 1 Pilot plant

30

Part 2 CCT Overview
Coal-fired Power Generation Technologies (Combustion Technologies)

2A6. Pressurized Fluidized-bed Combustion Technology (PFBC)
Research and development: Japan Coal Energy Center; and J-POWER
Project type: Coal Production and Utilization Technology Promotion Grant
Period: 1989-1999 (11 years)

Technology Overview

1. Background and process overview(1) The research and development of pressurized fluidized-bed(2) Overview of facilities

combined power generation technology was conducted at

Plant output 71.0 MWe

J-POWER’s Wakamatsu Coal Utilization Research Center (nowPressurized fluidized-bed combustion boiler (ABB-IHI production)

known as Wakamatsu Research Institute) using a 71 MWe-PFBC

Bubbling-type pressurized fluidized-bed, coal water paste

Plant, the first PFBC plant in Japan. The test plant was the first(70-75%) injection-type

plant in the world to adopt a full-scale ceramic tube filter (CTF)

Combustion temperature: 860oC

capable of collecting dust from high-temperature, high-pressure

Combustion air pressure: 1 MPa

gas at a high-performance level. An overview of the process isshown in Figure 1.

Ammonia water injection(Non-catalytic denitration)
Ash recirculation
cycloneCeramic tube filter(CTF)

Main steam/Reheated steam
593 C/593 C
Steam turbine
O

O

Air
Gas turbine

CTF ashFuel
nozzleIntercooler

Condenser

Coal,limestone,
water

Denitration
unit

Pressure
vesselBottom ash (BM)Deaerator

Water
supplypump

Fuel slurry pumpWater
supplyheaterEconomizer

Fig. 1 Flowchart of PFBC process31Clean Coal Technologies in Japan

2. Development objective and technology to be developed
PFBC technology development objectives:

elimination of the desulfurization unit.

(1) Increase efficiency through combined power generation

Results of PFBC technology development:utilizing pressurized fluidized-bed combustion with a gross(1) Gross efficiency of 43% was achieved by increasing efficiency

efficiency of 43%.

through combined power generation utilizing pressurized(2) Providing advanced environmental features, including:

fluidized-bed combustion.

SOx reduction through in-bed desulfurization; NOx reduction(2) SOx level of approximately 5 ppm through in-bed desulfurization;

through low-temperature combustion (approximately 860oC); Dust

NOx level of approximately 100 ppm through low-temperature

reduction by CTF; and CO2 reduction through increased

combustion (approximately 860oC), and dust of less than 1

efficiency.

mg/Nm3 by CTF.

(3) Space-savings through a compact pressurized boiler and the

3. Progress and development results
Detailed design of the facilities began in FY1990 and

1997. After that, the plant was modified to adopt the ash-recycling

construction began in April 1992, with equipment installation

system. Phase 2 of the demonstrative operation was conductedcommencing in October 1992. Test operations began in April

from August 1998 to December 1999. The cumulative operating

1993, while coal combustion was commenced in September

time of the PFBC system was 16,137 hours, including 10,981

1993, and 100% load capacity was achieved in January of 1994.

hours in phase 1 and 5,156 hours in phase 2. In phase 2, theThe two-stage cyclone system passed inspections before

system was operated continuously for 1,508 hours. Through theentering operations in September 1994, and the CTF passed

operation, valuable data and findings were made in terms ofinspections before entering operations in December 1994. Phase

performance and reliability. Three electric power companies have

1 of the demonstration operation was conducted until December

already applied these results during the construction ofcommercial facilities.

PFBC development schedule
FY1990

FY1991

FY1992

FY1993

FY1994

FY1995

FY1996

FY1997

FY1998FY1999Final assessment

FY1989Interim assessment

Fiscal year
Item

Basic and detailed design
Construction begins Integration
Construction of demonstration plant
Test operation and adjustments
Demonstration operation phase 1

Test operation
Modification

Modification

Demonstration operation phase 2

Test operation

4. Issues and feasibility of practical application
Due to its environment-friendly characteristics, including SOx

materials and waste by utilizing the technology’s superior

emissions of 10ppm or less, NOx emissions of 10 ppm, and dust

combustion performance; the in-bed desulfurization; theconcentration of 1mg/Nm3 or less, and also due to the space-combination of catalytic or non-catalytic denitration; and the high-savings brought about by the elimination of the desulfurization

temperature and high-performance dust collection from the CTF.

unit, the PFBC system is highly suitable for urban-operation.

An outstanding issue is improving the cost-efficiency by fully

These advantages are obtained by: the flexibility to utilize aleveraging these characteristics of the system and by selecting avariety of fuels, such as difficult-to-combust or low-grade

proper location.

Reference

Yamada et al., "Coal Combustion Power Generation Technology," Bulletin of the Japan Institute of Energy, Vol. 82, No. 11, pp. 822-829, November 2003.

32

Part 2 CCT Overview
Coal-fired Power Generation Technologies (Combustion Technologies)

2A7. Advanced Pressurized Fluidized-bed Combustion Technology (A-PFBC)
Research and development: Japan Coal Energy Center; J-POWER; Chubu Electric Power Co., Inc.;and Mitsubishi Heavy Industries, Ltd.
Project type: Coal Production and Utilization Technology Promotion Grant
Period: 1996-2002

Technology Overview

1. Overview
The development of high-efficiency power-generation technology

temperature at the inlet of the gas turbine from approximately

utilizing coal is an urgent issue from the perspective of reducing

850oC to approximately 1,350oC, and to recover the high-greenhouse gas emissions and conserving resources. Advanced

temperature steam, thus attaining more efficient powerPressurized Fluidized-bed Combustion (A-PFBC) technology is a

generation (approximately 46% net efficiency; approximately 40%

further advancement of the Pressurized Fluidized-bed Combustion

for existing coal-fired power plants) through combining PFBC(PFBC) technology. The development aim is to increase thetechnology with the fluidized-bed gasification technology.

Synthesis gas cooler
Limestone

Desulfurizer

CycloneCeramic filter

Partialgasifier
CombustorAsh

Gas turbine
Air
Char
Coal
Flue gasGas flowAir
AshSteam flow

Steam turbine

Oxdizer (PFBC)

Fig. 1 Flowchart of A-PFBC combined power generation system

2. Development objective and technology to be developed(2) Moderation of gasification conditions(1) High-efficiency power generation

Carbon conversion: approximately 85%

Net efficiency: approximately 46%- Increase of gas turbine inlet temperature- Gasification in the partial gasifier in combination with the(from approximately 850oC to approximately 1,350oC)

oxidizer (perfect oxidizing atmosphere)- Recovery of high-temperature steam(3) Utilization of results of related technologies(High-temperature steam recovery at the synthesis gas cooler- PFBC technology

applying the high-temperature desulfurizer)- Various coal gasification technologies

33

Clean Coal Technologies in Japan

3. Progress and development results
Aiming for the practical application of the above-describedsystem, the study team installed a small-scale processdevelopment unit (Fig. 3) at J-POWER’s Wakamatsu ResearchInstitute (Kita Kyushu City). The PDU test operations began in
July 2001. By the end of FY2002, the cumulative gasification
operation time had reached 1,200 hours, and the continuous
gasification operations had reached 190 hours. The PDU test
Desulfurizer

confirmed the successful integration of the three-reactors,
which was one of the objectives of the system validation, andthe acquired characteristics of each reactor, thus confirming thePartial gasifier

data necessary for scaling-up.
Further development requires a validation of the total system,

Oxidizer

combined with a gas turbine in a pilot-scale plant.
(1) Overview of the process development unit (PDU) test
Objectives of the test
For the three-reactor combined system (oxidizer, partial gasifier,and desulfurizer), (Fig. 2), data is acquired on thereaction characteristics and operation characteristics, and theFig. 2 PDU: Schematic layout of the three reactors

validation of the process is carried out in order to acquire
information necessary for scaling-up the system.
- Validation of the three-reactor link process- Confirmation of the performance of the individual systems(oxidation, gasification, desulfurization, etc.)- Confirmation of basic operability- Information on various characteristics, acquisition of data for
scaling-up, etc.

Fig. 3 PDU overview

A-PFBC development schedule
Fiscal year
Item

FY1996

FY1997

FY1998FY1999FY2000FY2001

FY2002(1) Research plan, technology study(2) Elementary test and F/S
Installation completed
Design, manufacturing, and installation(3) PDU test (15 t/d)

Test operation(4) Process evaluation

Reference

Preprint for the 13th Coal Utilization Technology Congress, "A-PFBC"; sponsored by the Center for Coal Utilization (now known as JCOAL).

34

Part 2 CCT Overview
Coal-fired Power Generation Technologies (Gasification Technologies)

2B1. Hydrogen-from-Coal Process (HYCOL)
Research and development: HYCOL Association [Idemitsu Kosan Co., Ltd. ; Osaka Gas Co., Ltd.;J-POWER; Tokyo Gas Co., Ltd.; Toho Gas Co., Ltd.; Nikko Kyoseki Co., Ltd.; The Japan Steel Works, Ltd.;
Hitachi Ltd.; and Mitsui Coal Liquefaction Co., Ltd.]
Project type: NEDO entrusted projectTechnology Overview

1. Background and process overview
The Hydrogen-from-Coal Process (HYCOL) is a gasification(2) Slag self-coating technology for the water-cooled tubes wastechnology utilizing an entrained bed, in which pulverized coal isapplied. This technology prolongs the life of the tubes andgasified with oxygen under high temperatures and high pressure.

improves the reliability of the gasifier.

Through the gasifier, medium calorific gas, rich in hydrogen and(3) A swirling gas flow distributor was developed and adopted ascarbon monoxide, is obtained. The technology is called thea technology to easily and uniformly distribute coal to multiple"HYCOL process." Through the shift reaction, the gas yields

burners.

carbon monoxide and converts steam to carbon dioxide and(4) Ash in coal is melted in the gasification furnace. The meltedhydrogen. After separating the carbon dioxide, the gas is purified

ash is discharged through the slag hole located in the furnace’s

to become high-purity hydrogen.

hearth. As a result of the swirling gas flow, a high temperature is

Hydrogen is used in oil refineries and in the chemical industry, as

maintained at the slag hole, ensuring a smooth flow of slag.

well as in the coal liquefaction process. On the other hand, the(5) The unreacted char discharged along with gas from thegas containing carbon monoxide is expected to be used widely

gasification furnace is separated by a cyclone or other suchas a raw material for synthetic chemical products, as a fuel for

device to recycle the material to the gasification furnace in afuel cells, and as a fuel in various industries.

high-temperature, high-pressure state, thus ensuring a complete

The HYCOL process has the following features:reaction.

(1) The process uses a dry-feed, one-chamber, two-stage(6) Ash in the coal is recovered as slag, which does not eluteswirling-entrained-bed gasification furnace. Pulverized coal,

toxic components. Combined with the advantage of an easypressurized in a lock hopper, is fed, to the gasification furnace via

recovery of the sulfur and nitrogen components, in the form ofburners in a swirling mode. Four burners are utilized in each

H2S and NH3, respectively, the ash recovery also significantly

stage. The oxygen feed and the gasification rate at the upper

contributes to a reduction in the environmental burden.

stage and lower stage are separately controlled. Throughout the

Coal that has a lower fuel ratio (fixed carbon to volatile matter) is

operation, high thermal efficiency is attained, and heavy load

more easily gasified.

gasification is performed.
2. Progress and development results

3. Issues and feasibility of practical application

The HYCOL association (made up of the nine above-listed

The development of a coal gasification fuel cell system (IGFC) for

private companies) carried out the research and development of

power generation utilizing HYCOL technology began in 1995,

the pilot plant, under entrustment from NEDO. Five private(EAGLE Project).

companies (Hitachi Ltd., Babcock-Hitachi K.K., Asahi Glass Co.,
Ltd., Shinagawa Refractories Co., Ltd., and NGK Spark Plug Co.,
Ltd.) carried out the basic study on the structure of the furnaceand on the materials, also under entrustment from NEDO.
For establishing the process, a pilot plant was constructed at
Sodegaura, Chiba. The operational study of the pilot plant was
conducted from 1991 to 1994. The performance target wasachieved, and the world’s most advanced gasification furnacetechnology was established.

35

Clean Coal Technologies in Japan

Water-washingprocess

Gasification process

Gasification
furnace

Water-washing
tower

Lock
hopperCoal

Pulverizedcoal
apparatus

Product gas incineration process

BoilerPretreatment process

Incineration
Waste
furnaceheat boiler
Distributor
Desulfurization unit

Lockhopper

Air heater

Recycled gas
compressor
Ash treatment process

Fig. 1 Process flowchart of pilot plant

Pilot plant: Specifications and target performance
Coal throughput

Max. 50 tons/day

Gasification agent

OxygenGasification pressure

30 kg/cm2(G)Gasification temperature

1,500-1,800 C

O2/Coal0.8-0.9 (weight ratio)

Produced gas volume

Approximately 91 kNm3/dayO

Gas composition

CO

61%

(design)

H2

31%

CO2

3%

Carbon conversion

98% or greater

Cold gas efficiency

78% or greater

36

Part 2 CCT Overview
Coal-fired Power Generation Technologies (Gasification Technologies)

2B2. Integrated Coal Gasification Combined Cycle (IGCC)
Research and development: Clean Coal Power R&D Co., Ltd.
(Until 2000, the study had been conducted as a joint activity of power companies led by Tokyo Electric Power Co., Inc.)
Project type: Grant for "Demonstration of Integrated Coal Gasification Combined Cycle Power Generation," the Agency
of Natural Resources and Energy of the Ministry of Economy, Trade and Industry
Period: 1999-2009
Technology Overview

1. Overview and objective of IGCC demonstration test
Integrated Coal Gasification

1. Improved power generation efficiency: Compared with

SyngasCombined Cycle (IGCC) is aconventional pulverized coal-fired power plants, IGCC can

Unreacted
coal (char)increase power generation efficiency by approximately 20% for

high-efficiency power generation
technology which gasifies coal
to be used as the fuel for gas
turbines.

Japanesecompanies

Reductor(gasificationchamber)

power

promotedtheresearch and development ofChar
recoveryunitcommercial plants.

Char

generation efficiency, the emissions of SOx, NOx, and dust per

2. Lower environmental burden: Owing to the increase in power
generated power unit are lower. In addition, CO2 emissions are
reduced to the level of the heavy-oil-fired power generation

Coal

IGCC technology, applying a
Nakoso pilot plant (PP)-type
gasifier1,2

astechnology 3.

the

The

process.
Coal
Air

core

Combustor(combustion
chamber)with low ash melting points, which is difficult to use in

Molten slag

conventional pulverized coal-fired power plants. As a result, IGCC

PP-typeWater

gasifier utilizes dry-coal-fed,
oxygen-enriched

3. Flexibility to use different grades of coal: IGCC can use coalAir

broadens the variety of coal grades that can be used in coal-fired

Slag hopper

power plants.

air-blown,

4. Increase in fields that can utilize the ash: Since IGCC

pressurized two-stage entrained
Molten slag

beds, as shown in Figure 1.

discharges coal ash in the form of glassy molten slag, the ash is

Fig. 1 Nakoso PP-type gasifierThis is expected to provide

expected to be effectively used as component for civil

higher efficiency than preceding gasifiers from abroad. On theengineering work.

basis of the feasibility study results, an IGCC demonstration test

5. Reduction of water consumption: Since the generated gas is

project was started with the aim of validating IGCC’s reliability,

desulfurized directly, IGCC does not need a flue gas

operability, maintainability, and profitability, and to confirm thedesulfurization unit, which consumes large amounts of water.

feasibility of a coal-fired IGCC commercial plant.

Accordingly, IGCC uses significantly less water than conventional

Compared with conventional pulverized coal-fired power plants,

pulverized coal-fired power plants.

IGCC has many advantages, such as:
2. Specifications and objective of IGCC demonstration plant
Figure 2 shows the process flow of the IGCC demonstration

about one-half of a commercial plant. The gasifier is of theplant. Table 1 lists the main specifications and target values.

Nakoso PP-type. A wet gas clean up system with MDEA has

Figure 3 is a conceptional drawing of the IGCC demonstration

been adopted. The gas turbine is a 1200oC-class gas turbine, withplant. The scale of the plant (250 MW, 1700 t/d of coal feed) isa corresponding output of 250 MW.

Coal
Gasifier

Heat
exchanger

Gas cleanupChar
recovery unit
Combustor
Gas turbine

Table 1 Main specifications and target values of IGCC demonstration plant
Air

OutputCoal feed rate

Steam turbine

GasifierDry-coal-fed, air-blown,
Pressurized, two-stage entrained beds

Gas cleanup
Gas turbine
Target thermal Gross efficiency
efficiency (LHV) Net efficiency
Environmental SOx emission concentration
characteristics NOx emission concentration(target values) Dust emission concentration

Wet gas cleanup (MDEA) + gypsum recovery
1200OC-class48%
42%
8 ppm (O2 conversion: 16%)
5 ppm (O2 conversion: 16%)
4 mg/Nm3 (O2 conversion: 16%)Type

Waste heatrecovery boiler

Nitrogen

OxygenStack

Gasifier
Heat exchanger
Air separator

Fig. 2 Process flow of the IGCC demonstration plant

37

250 MW class
Approximately 1,700 t/d

Clean Coal Technologies in Japan

3. Organization for executing the IGCC demonstration test
The IGCC demonstrative test is being conducted by Clean Coal
Power R&D Co., Ltd. (CCP R&D Co., Ltd.), which was established

Gasification
train

by nine power companies and J-POWER. The Ministry ofCombined-cycle
block

Economy, Trade and Industry is subsidizing 30% of the project
costs, and 70% of the costs are being borne by a total of elevenentities: nine power companies, J-POWER and the Central
Research Institute of Electric Power Industry (Fig. 4).

METI
30% subsidy
Joint project agreement
70% contribution

Gas cleanup train

Nine power companies
J-POWERCCP R&D Co., Ltd.
Personnel

Central Research Institute of ElectricPower Industry

Fig. 4 Scheme of demonstration project

Fig. 3 Conceptional drawing of the IGCC demonstration plant

4. Timetable and progress
Table 2 shows the schedule of the demonstration project. The

2006. A three-year test operation of the plant is scheduled todemonstration plant has been under construction since March

begin in the second half of FY2007.

Table 2 IGCC demonstration project timetable
Fiscal year

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

Preliminary validation test
Design of demonstration plant
Environmental assessment
Construction of demonstration plant
Plant operation and demonstration test

5. Activities to date
The pilot plant test (200 t/d of coal feed), which is a preliminary stage

Joban Joint Power Co., Ltd.’s
Nakoso power plantof the demonstration test, was carried out from 1986 to 1996 at

Former site of pilot plant;
Site selected for demonstration plant

Joban Joint Power Co., Ltd.’s Nakoso power plant in Iwaki City,
Fukushima, (Fig. 5). The pilot plant test was conducted jointly by nine
power companies, plus J-POWER and the Central Research Instituteof Electric Power Industry, as an entrusted project of NEDO. A pilot
plant test of 4,770 hours, including 789 hours of continuous
operation, proved the practical applicability of the IGCC technology3.
Based on the success of the pilot plant test, a demonstration test
introduced an optimum system, which was selected following afeasibility study conducted by NEDO. After conducting a variety ofsurveys, Joban Joint Power Co., Ltd.’s Nakoso power plant wasagain selected as the site for the demonstration test, which is
being conducted at the same site of the pilot plant.

Fig. 5 Site for demonstration test. (Iwaki City, Fukushima)

References

1) Shozo Kaneko et al., "250MW AIR BLOWN IGCC DEMONSTRATION PLANT PROJECT,"Proceedings of the ICOPE-03, pp. 163-167, 2003.
2) Christopher Higman, Maarten van der Burgt, "Gasification," pp. 126-128, 2003.
3) Narimitsu Araki and Yoshiharu Hanai: Bulletin of Japan Energy, 75-9, pp. 839-850, 1996.
38

Part 2 CCT Overview
Coal-fired Power Generation Technologies (Gasification Technologies)

2B3. Multi-purpose Coal Gasification Technology Development (EAGLE)
Research and development: New Energy and Industrial Technology Development Organization;
J-POWER; Japan Coal Energy Center; and Babcock Hitachi K.K.
Project type: Coal Production and Utilization Technology Promotion Grant; and Grant for the Development ofAdvanced Technology for Generation of Fuel Gas for Fuel Cell Development
Period: 1995-2006 (12 years)

Technology Overview

1. Summary of technology
The purpose of EAGLE (Multi-purpose Coal Gasification

chemicals, hydrogen production, synthetic liquid fuel, electricTechnology Development) is to reduce the environmental burden,

power generation and other purposes.

particularly global warming gas emissions. The EAGLE projectThis gasifier, combined with gas turbines, steam turbines, and fuelaims to establish a coal gasification system utilizing the mostcells, will provide an integrated coal gasification fuel cell combined-

advanced oxygen-blown, single-chamber, two-stage swirling flow

cycle system (IGFC) that can be expected to reduce CO2

gasifier that allows the highly-efficient production of synthetic gas

emissions by up to 30% relative to existing thermal power plants.

(CO+H2), and which can be widely used as a raw material for2. Development targets and technology to be developed
The EAGLE project’s development targets are shown in Table 1.

Table 1 Development targets

When utilizing coal-gasified gas for fuel cell power generation or

Item

Development target

the production of synthetic fuel, hydrogen, or chemical fertilizers,
sulfur compounds and other impurities contained in the gas may

Coal gasification
performance

Carbon conversion rate: 98% or higher
Cold gas efficiency: 78% or higher
Gas calorific value (higher): 10,000 kJ/m3N or higher

Gas purification
performance

Sulfur compounds: 1 ppm or less
Halogen compounds: 1 ppm or lessAmmonia: 1 ppm or less
Dust: 1 mg/m3N

Miscellaneous

Continuous operation: 1,000 hr or longer
Acquisition of gasification data for 5 or more coal types
Acquisition of scale-up datacontaminate the fuel cells and the reactor catalyst, thereby
degrading their performance. The EAGLE project, therefore, setstargets to meet the purity levels required by fuel cells andcatalysts. Since there have been few reports published on thematter, particularly on the effects of fuel cell contaminating
materials (including halogens), the project set target levels withreference to reports by the U.S. Department of Energy (DOE), theMCFC Association of Japan, and other organizations.

3. Pilot test plant
In this project, a pilot test plant with a coal processing capacity ofplant consists of the following systems: coal pretreatment, coal

150 tons/day was built on the premises of the J-POWER’s

gasification, air separation, gas purification, effluent treatment,

Wakamatsu Research Institute. Operational testing is now

and produced gas combustion, as well as a gas turbine.

underway. Figure 1 shows a flowchart of the pilot test plant andTable 2 provides the specifications of the major systems. The test
Table 2 Specifications of major systems
Coal gasification facilities

Coal gasifier

Precision desulfurizer
Gasifier

Item

Gas purification facilities

SGC
MDEA
regenerator

Pulverized coal
COS converter

Coal processing capacity

Acid gas
Furnace

FilterPrimary
scrubber

Limestone
absorber

Secondary MDEA
scrubberabsorber

Incinerator

Compressor

Rectifier

HRSG

Air

Air separator

Stack

Gas turbine facility

Fig. 1 Flowchart of EAGLE 150 t/d pilot plant
39

Oxygen-blown, single-chamber,
two-stage swirling-flow entrained
bed gasifier

150t/d (6.3t/hr)

Gasification temperature

1,200-1,600℃

Gasification pressure

2.5MPaGas refinery

Wet chemical absorption type

Absorbing solution

Methyl diethanolamine (MDEA)

Processing capacity

Approx. 14,800 m3N/h

Char
Slag

Specifications

Sulfur recovery unit

Wet limestone-gypsum method

Air separation system

Pressurized cryogenic separation type

Air pressure

1.09MPa

Air processing capacity

Approx. 27,500m3N/hr

Oxygen production

Approx. 4.600m3N/hr

Oxygen purity

95%

Gas turbine

Open simple-cycle, single-shaft typeOutput8,000kWClean Coal Technologies in Japan

4. Timetable and progress
Table 3 Achievement of research targets

This project is being promoted by a joint

Final target

team from the New Energy and Industrial

Achievements

Gas electric power generation 10,000 kJ/m3N or higher

Technology Development Organization

Coal gasification
Carbon conversion rate
performance
Cold gas efficiency(NEDO) and the J-POWER. The pilot
plant (150 t/d) was constructed on thepremises of J-POWER’s Wakamatsu

Sulfur compounds

Research Institute (Photo 1), and operational

Gas purification Ammonia
performance
Halogen compounds

testing is now underway.

Dust

10,100 kJ/m3N or higher

98% or higher

99% or higher

78% or higher

78% or higher

1 ppm or less

N.D. (<1 ppm or less)

1 ppm or less

1 ppm1

1 ppm or less

1 ppm or less

1 mg/m3N

1 mg/m3N or less2

Notes: Coal processing capacity of 150 t/d verified
1: at the outlet of the absorber, 2: at the outlet of the second scrubber

EAGLE development timetable
Fiscal year
1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

F/S
Conceptual/detailed design
Fabrication and construction
Operation research

5. Future plans
Major future developments are planned for the project, including

improve generation efficiency relative to conventional pulverized

support for using multiple grades of coal, acquisition of scale-up

coal-fired power generation systems, and is the ultimate power

data, technological enhancements for improved cost-efficiency,

generation system, with power generation efficiency exceeding

as well as system verification. With a view to achieving the

55%. EAGLE plants using oxygen-blown coal gasifiers produce

development targets ahead of schedule, these challenges havecoal-gasified gas with a substantially lower proportion of non-CO

already been addressed. EAGLE technology can be effectively

and H2 gas components (i.e., N2 and other gases). Utilization ofused in integrated coal gasification combined cycle (IGCC) power

this gas allows the efficient production of liquid fuels or chemical

generation systems, which combine gas turbine generation

feedstocks.

systems and steam turbine generation systems, or in an

In the U.S., there is a proposed project to combine a hydrogen

integrated coal gasification fuel cell combined-cycle system

gas turbine generation system or a fuel cell power generation(IGFC). This may be the ultimate triple-combined-cycle based on

system that uses coal-derived hydrogen with a CO2 separation,

combining IGCC with fuel cells. IGFC is expected to dramaticallycollection and segregation system. EAGLE technology is not only
expected to meet the future demands of a hydrogen society, but
is also expected to meet the demands of today.

Syngas cooler

Gasifier

Gas refining

FilterCoal
Nitrogen

Air

OxygenHRSG
Expansion turbine
FC

Compressor
Steam turbine
Heat
recoveryboilerCirculation
blowerCirculation
blower

Gas turbine

Air

Catalyst burner

Photo 1 Pilot test facilities

Fig. 2 IGFC system

Reference

1) Masao Sotooka: Coal Gasification Technology (II) — Multi-purpose (Fuel-cell) Coal Gasification Technology Development (EAGLE),
The Japan Institute of Energy, Vol.82, No. 11, pp. 836-840, November 2003.
40

Part 2 CCT Overview
Coal-fired Power Generation Technologies (Gasification Technologies)

Coal Gasification Fuel Cell Combined Cycle Electric
2B4. Integrated
Power Generating Technology (IGFC)
Technology Overview

1. IGFC process flow
The integrated coal gasification fuel cell combined cycle (IGFC)

reduce CO2 emissions by approximately 30% from the level ofgasifies coal for use in triple combined power generation, which

existing pulverized coal-fired power generation systems. IGFC iscombines three different types of generation systems: fuel cells,

expected to become a coal-fired power generation technology ofgas turbines and steam turbines. This high-efficiency power

the future, although there are still many challenges to be overcome

generation technology is expected to provide power generation

for commercialization, including the development of inexpensive

efficiency of 55% or higher, if successfully developed, and tohigh-efficiency fuel cells (Fig. 1).

Coal

Power generation efficiency: 55%

Coal gasifier

CO2 emission reduction: 30%

Desulfurizer

Gypsum collector
Scrubber
Syngas cooler
Regenerator
GGH

GypsumCOS converter

Filter
AC
DC

FC
Slag

Wastewater treatment system

HRSG

Combustion turbine

RectifierStack
Condenser
Steam turbine

Fig. 1 IGFC process flowchart

2. Types and features of fuel cells
Fuel cells employ the electrochemical reaction between hydrogen

phosphoric acid fuel cells (PAFC), molten carbonate fuel cells

and oxygen to directly generate power. With their high-efficiency(MCFC), solid oxide fuel cells (SOFC), and solid polymer electrolyte

and excellent environmental features, fuel cells are now in thefuel cells (PEFC).

limelight. They can be classified by electrolyte material intoType

Phosphoric acid (PAFC)

Electrolyte

Phosphoric acid aqueous solution Li/Na carbonate

Ionic conductor

H+

Molten carbonate (MCFC)

CO3

Solid polymer electrolyte (PEFC)

Stabilized zirconia

Solid polymer membrane

2-

H+

O

Approx. 650 to 700 C

900 to 1000 C

70 to 90oC

Generation efficiency (HHV) 35% to 42%

45% to 60%

45% to 65%

30% to 40%

Raw materials and fuels

Natural gas, methanol, naphtha

Natural gas, methanol, naphtha, coal

Natural gas, methanol, naphtha, coal Natural gas, methanol, naphtha

Application

Co-generation anddistributed generation

Co-generation and distributed
generation, substitute for thermal
power generation

Co-generation and distributed
generation, substitute for thermal
power generation

Operating temperatureo2-

Solid oxide (SOFC)

Approx. 200 CooCo-generation and portable
power supply, automobiles

Among the fuel cells above, MCFC and SOFC operate at highheat and converts the heat into electrical energy. Unlike thistemperatures and are expected to be highly-efficient technologies

system, fuel cells derive electrical energy directly with lower

for next-generation large-scale power plants due to the following

energy losses and higher generation efficiency.

features: (1) they can be used in combination with gas turbines,

SOFC, consisting of ion-conducting ceramics, generate heat atand (2) they can accept coal gas.

temperatures as high as 900oC to 1,000oC during the chemical

SOFC produce power through an electrochemical reaction

reaction. Combined with gas turbine generation, SOFC canbetween hydrogen, which has been derived from gasified fuel, andprovide higher generation efficiency than other types of fuel cells.

oxygen in the air. This mechanism is the reverse process of the

Besides coal-gasified gas, LNG, methanol or biogas can also beelectrolysis of water.

used as fuel.

The traditional power generation system burns fuel to generate
41

Clean Coal Technologies in Japan

Next-generation, High-efficiency Integrated Coal Gasification Electric

2B5. Power Generating Process (A-IGCC/A-IGFC)
Technology Overview

1. Advanced IGCC/IGFC with exergy recovery technology
The integrated coal gasification combined cycle (IGCC) power

method of energy utilization, the A-IGCC/A-IGFC (Advanced IGCC/IGFC)

generation system under development in Japan provides asystem directs recycled heat from gas turbines or fuel cells back into

generation efficiency of 48% for dry gas cleaning. Also, thesteam reforming gasifiers that employ endothermic reactions. This next-

integrated coal gasification fuel cell combined cycle (IGFC) provides

generation exergy recovery-type IGCC/IGFC being studied. With exergy

55%. These efficiency levels are 7% to 8% lower than that of natural

recovery, the A-IGCC, using 1700oC gas turbines, is expected to provide

gas-fired IGCC/IGFC. An important challenge for Japan is to develop

a generation efficiency of 57% and the A-IGFC, employing fuel cells, istechnologies to more efficiently utilize coal, an energy source that

expected to provide a generation efficiency as high as 65%. Thus, thiscan be stably supplied.

technology is expected to have the potential to bring about a dramatic

Unlike the existing IGCC/IGFC system that integrates partial oxidation

increase in system efficiency, contributing, in the future, to the provision

gasifiers, fuel cells, and gas and steam turbines using a cascadeof energy resources and a reduction in CO2 emissions.
65

Existing IGCC/IGFC

A-IGCC/IGFC

Systemcombination

Cascade method

Exergy recovery

Gasification

High-temperature partial
oxidation (1100 to 1500oC)

Steam reforming(700 to 1000oC)

Gasifiers

Entrained flow

Multi-loop high density CFB

Generation
efficiency

46 to 48% (55%)

53 to 57% (65%)

Power generation efficiency [%]Table 1 Comparison between existing IGCC and A-IGCC

A-IGFC up to
65%

60
55

A-IGCC 1700oC-class
GT 57%

A-IGCC 1500oC-class GT 53%

IGFC 55%
IGCC 1500oC-class
GT wet gas cleaning
IGCC demonstration 46%
unit 1200oC-classIGCC
A-PFBC 1300oC-class GT 46%
GT dry gas cleaning
1500oC-class40.5%
GT dry gas cleaning 48%

50

45

40
Year20002010
2020
Year of commercialization

2030

Fig. 1 Projection of A-IGCC/IGFC efficiency

2. Overview of A-IGFC
Figure 2 is a schematic drawing of the basic A-IGFC processes. The

approximately 80%. On the other hand, the exergy-recovering IGFC

existing IGFC, which uses energy in a cascade method, integrates

reuses the high-temperature heat generated by the fuel cells in thea gasifier, fuel cells, gas turbines and a steam turbine into a

gasifier for steam reforming gasification by making use of an

cascade-type system. Hydrogen-rich gas produced in the gasifier isendothermic reaction. A-IGFC, using exergy recovery technology,

purified and then sent to the fuel cell unit. Part of the fuel that has

can be expected to substantially improve the generation efficiency.

not been used in the fuel cell unit is transferred to the gas turbines

Recovering waste heat from the fuel cells with low exergy loss andfor power generation. Since this process provides only a low fuelreusing the heat for steam reforming gasification that relies on an

utilization rate, the inlet temperature of the gas turbines is aroundendothermic reaction will greatly enhance the cold gas efficiency and1100oC and the power generation efficiency is not more than 55%.

substantially reduce the exergy losses due to combustion.

This is a result of the cold gas efficiency of coal, which is as low as

A-IGFC efficiency: 64.5% (60% plus approximately 5% loss for internal use)
Calculation with SOFC fuel utilization rate of 75% and efficiency of 40%

Ultra-supercriticalpulverized coalunit (USC)

CO2 : 63.5 kg/s, H2: 6.4 kg/s, H2 O: 6.2 kg/s

Fuel cell power
generator

179.9 MJ/s
273.9 MJ/s
1000

1332.2Gas
turbine 147.6
MJ/s
No. 2
454.3

103.1
MJ/s

5.55 kPa

Gas turbine 48
MJ/s
No. 1

Coal: 23kg/s（667MJ/s）
Steam: 53 kg/s
700

Gas turbine
(GT)

USC

ACC
ClosedGTCC

AHAT

Hydrogenturbine

IGCC(O2 injection)

204.3
MJ/s

IGHAT

IGCC/IGHAT(coproduction)

Zero-emission
high-efficiency
power generation

A-IGCCsystem

IGCC(air injection)

Fuel cells
(FC)
13.0
MJ/s

ACC

Gasifier

5 MPa
727.8
20 MPa400
53 kg/s

USC

Coal gasifier

P=1.0 MPa, T=1000

PFBC

IGFC

A-PFBC

A-IGFC

FC
combined

3 MPa
2000

Steam turbine

2010

2020

2030

Fig. 3 High-efficiency power generation technology development

Fig. 2 Schematic drawing of basic A-IGFC processes
42Part 2 CCT Overview
Iron Making and General Industry Technologies (Iron Making Technologies)

3A1. Formed Coke Process (FCP)
Members andin chargeof researchJapanand development
Researchdevelopment:
Coal Energy Center; and Japan Iron and Steel Federation
Period: 1978-1986 (9 years)

Technology Overview

1. Overview

3. Results of study

The formed coke process (FCP) utilizes noncaking coal as the

1. Production of formed coke from 100% noncaking coalmain raw material. Next, a binder is used to allow the coal to be

The pilot plant was normally operated with a blend of 70%

shaped, and then it is carbonized in formed shapes in a verticalnoncaking coal and 30% caking coal; however, 100% noncaking

furnace to obtain coke.

coal operation was also attained.
2. Establishing stable operating technology and engineering
technology

2. Features

The pilot plant was operated for an extended period at the facility

A series of steps are employed in FCP, including raw material

capacity of 200 tons/day. Production of 300 tons/day, or 1.5 times

processing, shaping, carbonizing the formed coal, and coolingthe designed capacity, was also achieved. Regarding the unit

the carbonized coke. In particular, the carbonizing and coolingrequirement of heat, 320 Mcal/t-formed coal was achieved.

steps are conducted in a vertical furnace within an enclosed

3. Extended period of operation and continuous use of 20%

system, providing many superior features in terms of work

formed coke in large blast furnace

environment, work productivity, ease of system starts and stops.

In a large blast furnace, a long and continuous operating test was

Relative to conventional chamber ovens, FCP systems arecarried out for 74 days with standard 20% formed coke and acompact, meaning less installation space is required.

maximum blend of 30% formed coke to confirm that the formed
coke can be used in a similar way as chamber oven coke.

4. Research and development progress
Table 1 Research and development progress
Fiscal year

1978

1979

1980

1981

1982

1983

1984

1985

Core

Construction
Pilot plant test
Test operation

43

1986

Clean Coal Technologies in Japan

Flow chart of continuous formed coke production

Noncaking coal

Caking coal

Carbonizing stage

1. Drying

2. Pulverizing
BinderForming stage

The formed coal is fed to the carbonization furnace (5),where the coal passes through the low- temperature
carbonizing zone (6). The coal is then heated too1000 C in the high-temperature carbonizing zone (7) toundergo carbonization. The heat-up rate is controlled toprevent the coal from collapsing and breaking causedby expansion and contraction. The carbonized coalo(coke), is cooled to 100 C or cooler in the cooling zone(8) by ambient temperature gas injected from thebottom of the furnace before the formed coal isdischarged from the furnace.

Noncaking coal is the main 3. Kneading
raw material (60-80%). The
coal is dried to a watercontent of 2-3%, (1).
The dried coal is next
pulverized (2). After a binder 4. Forming
is added to the pulverized
coal, the mixture is kneaded(3), and formed (4), thus
Formed coalproducing formed coal.

Generated gasoThe coke oven gas (300-350 C) exiting the top of the furnace
is cooled by the precooler (9) and the primary cooler (10).
After the removal of tar mist (11), most of the gas is recycled
to the furnace. The surplus portion of the gas is extracted
from the system, and then rectified and desulfurized to
become a clean fuel having a high calorific value of
3800kcal/Nm3.

9. Precooler

10. Primarycooler

5. Carbonization furnace

11. Electric precipitator(Generated gas)

Main blower
6. Low-temperature carbonizing zone

Ammonia water
12. Decanter
Tar

7. High-temperature carbonizing zone

Byproducts
8. Cooling zone

13. High-temperature
gas heating furnace
15. Ejector

14. Low-temperature
gas heating furnace

Gas recycling
Formed coke

The liquid in the gas is
directed to the decanter (12)to separate ammonia waterand tar by decantation andprecipitation. Each of these
byproducts is sent to respective
existing plants for further
treatment. After treated, thetar is reused as the binder for
the formed coke.

After the tar mist has been removed in the electric precipitator, the gas isheated to approximately 1000oC in the high-temperature gas heating
furnace (13). It is then injected into the high-temperature carbonizing zone
(7). The gas, heated to 450oC in the low-temperature gas heating furnace(14) drives the ejector (15). The ejector (15) draws in the high-temperature
gas that was used to cool the coke. Next, the gas is fed to the lowtemperature carbonizing zone (6) at a temperature of approximately 600oC.
44

Part 2 CCT Overview
Iron Making and General Industry Technologies (Iron Making Technologies)

3A2. Pulverized Coal Injection for Blast Furnaces (PCI)
Research and development: Nippon Steel Corp. and other blast furnace steel makers
Period: Successful introduction of the technology to domestic blast furnaces started in 1981

Technology Overview

1. Background and process overview
The injection of pulverized coal into blast furnaces in Japan

4. Drying, pulverizing, and collection of coal conducted in two parallelbegan at Nippon Steel Corp.’s Oita No. 1 blast furnace in 1981.

lines, assuring stable operation of blast furnace.

Although the main reducing material in blast furnaces is coke,

5. Flow velocity of carrier air and pressure resistance of

blast furnace operators during and after the 1960s utilized heavyequipment set in consideration of prevention of fire andoil as a companion fuel, injecting it through the tuyeres to

explosions.
Bag filter

enhance the productivity, efficiency, and scaling up potential.
After the two oil crises, however, the high price of heavy oil forced

Cyclonethe producers to switch exclusively to coke, meaning coke wasRaw coal bunker

solely relied upon as the reducing material. Nevertheless, there

Receivinghopperwas a desire for an inexpensive heavy-oil-alternative companion
fuel to reduce costs and ensure the stable operation of blast

Reservoirtankfurnaces.
To this end, an ARMCO pulverized coal injection system was

P.A. fanDistributor

Feederintroduction of this technology in Japan (Fig. 1). This system

Air heater

Pulverizer

featured the following:1

1. High-pressure transportation and injection lines with no
Feed tank3

Furnace
Disperser

mechanically rotating components, thereby avoiding wear and2

Transport line

installed at the Oita No. 1 blast furnace, marking the firsttear damage.
2. No recycling of gas, assuring reliable operation.

N2 compressor

O.T.

3. Distribution of pulverized coal fed to individual tuyeres,Air compressor

ensuring uniform distribution utilizing geometrically symmetricFig. 1 Process flowchart of pulverized coal injection facility
at Oita No. 1 blast furnace

flow characteristics of fluid.

2. Development objectives and technology to be developed
Field tests of the introduced technology had been performed

2. Model plant test (1 t/hr scale) for coal treatment, transportation,

abroad. Considering the differences in facility configurations andand control.

scale, as well as operating conditions in Japan versus abroad, a

3. Test to inject coal through a single tuyere into an actual furnace:study team conducted tests and investigations, focusing on the

Combustibility evaluation at the tuyere of an actual furnace, as

following items, and reflected the results in the design.

well as the sampling and evaluation of coke inside the furnace.

1. Pulverized coal combustion test: The influence of the grade and4. The distribution of pulverized coal along the circumference:

size of the pulverized coal, the temperature, pressure, and oxygen

Utilizing a prototype, studies were made to understand the powderrich condition of the air feed, and other variables were evaluated.

flow characteristics and to determine the distribution accuracy.

3. Progress and development results
Considering the heavy oil injection level during an increased

Following the domestic technology, Kobe Steel, Ltd. introduced

production rate period and the experience of long-term results, thethe U.S. Petrocarb technology and constructed the Kakogawa No.

capacity of the Oita No. 1 blast furnace was designed for 80 kg/t. Two

2 blast furnace and the Kobe No. 3 blast furnace in 1983, as themill lines, each having 25 t/hr capacity, were installed. After the start"Kobelco system." Following that, ARMCO systems wereof the plant, the equipment operation and injection operation

introduced into Nippon Steel’s Nagoya No. 1 blast furnace andfunctioned smoothly, establishing a stable production system.

Nisshin Steel Kure No. 2 blast furnace, which entered commercial

After the success of the Oita No. 1 blast furnace, Godo Steel, Ltd.

operation in 1984. In 1986, pulverized coal injection equipment

began operating an exclusively-developed system in 1982.

for blast furnaces was adopted at 16 sites in Japan, accounting

45

Clean Coal Technologies in Japan200

for 50% of the market. The number of blast furnaces employing

550

the technology had increased to 25 in 1996. In 1998, all the
injection equipment, which increased the average domestic
pulverized coal ratio to a 130 kg/t level, (Fig. 2). Table 1 shows thevarious types of injection for the blast furnace pulverized coalequipment. Table 2 shows the highest level attained in Japan for
the typical operational index of blast furnaces utilizing pulverizedcoal injection technology.

150

500
Coke rate (mean)

PC rate (mean)

100

450

50

400

Coke rate (kg/t-pig)

PC rate (kg/t-pig), Number of PCIBF

operating domestic blast furnaces employed the pulverized coal

Number of BF equipped with PCI
0
1980

1990
year

350

2000

Fig. 2 Increase in installations of pulverized coal injection
for blast furnaces technology in Japan
Table 1 Various types of pulverized coal injection equipment for blast furnaces
Type of distribution/transportation

Pneumatic
conveyingconcentration

Velocity

Pipe arrangement/
flow rate control

Low

High

Low

Users

Investment

Carrier gas pressureand flow rate (Downtake)National Steel,
Kobe Steel,JFE (NKK)

MediumHigh

Same as above, but uptake

JFE (Kawasaki Steel)MediumHigh

Low

Same as above + Flow meter

Thyssen

Large

MediumLow

Rotary valve

Dunkerque

MediumSimon Macawber

Low

High

Coal pump

Scunthorpe

Large

ARMCO

Low

High

Uniformly distributed to give
uniform pressure drop acrossindividual pipes

Nippon Steel Corp.,
Hoogovens

Small

High

Low

Uniformly distributedby throttled pipes

Sidmar, Solac Fod

Small

High

Low

Same as above

Dunkerque, Taranto

Small

Low

Rotary feeder + uniform
pressure drop (one way)
distribution

Sumitomo
Metal Mining Co., Ltd.

MediumProcess

Petrocarb
DENKA
Kuettner

Pneumatic conveying
from feed tank directly
to each tuyereformerly PW

new PM
Klockner

Feed tank
Main pipe
Distributor
TuyereSumitomo
Metal Mining Co., Ltd.

Low

Table 2 Highest domestic level operational indicies for blast furnaces with pulverized coal injection
Month
and
year

Steel works, blast furnace

Coal dust ratio
kg/tCoke ratio
kg/t

Reducing material ratio
kg/tTapping ratio
t/d/m3

Maximum pulverized coal ratio (PCR)

6/98

Fukuyama No. 3 blast furnace

266

289

555

1.84

Minimum coke ratio (CR)

3/99

Kobe No. 3 blast furnace

214

288

502

2.06

Minimum reducing material ratio (RAR)

3/94

Oita No. 1 blast furnace

122

342

464

1.95

Maximum tapping ratio

1/97

Nagoya No. 1 blast furnace

137

350

487

2.63

4. Issues and feasibility of practical application
The average lifespan for domestic coke ovens has reachedinnovations to blast furnaces: recycled materials, such as waste

approximately 30 years, and the importance of pulverized coalplastics and biomass, as well as recycled ores can be injected

injection technology as a companion fuel for blast furnaces

with pulverized coal into the furnaces via tuyeres. Thus, theincreases year by year. Compared with coke, which depends ontechnology is expected to be developed as core blast furnace

caking coal, pulverized coal increases the potential for thetechnology, addressing resource, energy, and carbon dioxide

injection material owing to the adaptability of coal resources.

issues.

Pulverized coal injection technology has the potential to spur
Reference

Shinjiro Waguri: Ferram, Vol. 8, p. 371, 2003.
46

Part 2 CCT Overview
Iron Making and General Industry Technologies (Iron Making Technologies)

3A3. Direct Iron Ore Smelting Reduction Process (DIOS)
Research and development: Japan Coal Energy Center; and Japan Iron and Steel Federation
Period: 1988-1995 (8 years)

Technology Overview

1. Overview

3. Results of study

The Direct Iron Ore Smelting Reduction Process (DIOS) directly

A feasibility study was undertaken on the installation of a newuses noncaking coal in a powder or granular form, and iron ore

commercial blast furnace plant and of DIOS in a waterfront area.

without the use of coke or a sintering process, which are normally

Considering its superiority to the blast furnace process as

required in blast furnace processes. The noncaking coal isdescribed below, the feasibility of DIOS can be demonstrated for

directly fed to a smelting reduction furnace, while the iron ore is

a 6,000 ton molten iron model production facility (annual

preliminarily reduced before being fed to the furnace, thus

production of 2 million tons).

producing molten iron.

1. Investment cost reduced by 35%.
2. Molten iron production cost decreased by 19%.

2. Features

3. Coal consumed, 730-750 kg per 1 ton of molten iron production,

1. Possibility of utilizing inexpensive raw materials and fuelequivalent to that of the blast furnace process.

(noncaking coal, in-house dust, etc.)

4. Net energy consumption decreased by 3 to 4%.

2. Low operating cost

5. CO2 emissions in the iron making process decreased by 4 to

3. Responds flexibly to variations in production rate

5%.

4. Compact and small incremental investment
5. Stable, high-quality supply of iron source available
6. Effective use of coal energy
7. Easy co-production of energy (co-generation)
8. Low environmental load (low SOx, NOx, CO2, dust generation,
no coke oven gas leaks)
4. Research and development progress
Table 1 Research and development progress
Fiscal year

1988

1989

1990

1991

1992

1993

1994

1995

Core technology study

Construction
Test operation

Pilot plant test

1) Core technology study (FY1988-FY1990)

2. With various raw materials, the equipment and operatingCore technologies necessary for the construction of the pilot

specifications to achieve high thermal efficiency, as an alternativeplant were established. These core technologies include an

to the blast furnace, were determined.

increase in the thermal efficiency of a smelting reduction furnace

3. Technology

forwater-coolingthefurnacebodywas(SRF), the technology to be integrated with a preliminary

established. A conceptual design and an economic evaluation

reduction furnace (PRF), the molten slag discharge technology,(FS) for commercial facilities was conducted. The conditions ofand the scale-up of an SRF.

the facilities and of the operations to prove the superiority versus

2) Pilot plant test (FY1993-FY1995)

the blast furnace, as shown in the results of the research, was

1. The possibility of directly using powder, granular ore, and coalclarified.

was confirmed, and necessary equipment specifications were
determined.

47

Clean Coal Technologies in Japan

Coal
952kg

Flux
80kg

Plant size

500 t-molten iron/day

Smelting reduction
furnace

Height 9.3m
Inner diameter 3.7m
Pressure less than 2.0kg/cm2 — G (300kPa)

Pre-reduction
furnace

Height 8.0m
Inner diameter 2.7m

Iron ore
1450kgPre-heating
furnaceRD 8.7%2,326Nm3
2,789Mcal (11.7GJ)

RD 8.6%
600 C
O

Pre-reduction
furnace
Venturi scrubber
RD 27.0%
779 C
O

O2
608Nm3RD 27.1%

Pressure control valve

OD 31.6%
Off-gasTapping device
Smelting reduction
furnace
1.9kg/cm2 — G (290kPa)
Molten iron

24.7t/h
1,540OC
1,000kg
Legend

N2 70Nm3

OD: Oxidation degree
RD: Reduction degree

Fig. 1 Process flowchart for DIOS pilot plant (per 1,000kg of molten iron)48

Part 2 CCT Overview
Iron Making and General Industry Technologies (Iron Making Technologies)

Super Coke Oven for Productivity and Environment Enhancement

3A4. toward the 21st Century (SCOPE21)

Research and development: Japan Coal Energy Center; and Japan Iron and Steel Federation
Project type: Coal Production and Utilization Technology Promotion Grant
Period: 1994-2003 (10 years)

Technology Overview

1. Background and process overview
The existing coke production process, which rapidly heats the coal at

The SCOPE21 process aims to develop an innovative processo350 C (low temperature carbonization), as opposed to the old

responding to the needs of the 21st century in terms of themethod employing a 1200oC coke furnace, has many problems.

effective use of coal resources, improvements in productivity, andThese include the unavoidable coal grade limitation necessitating theadvancement of environmental and energy technologies. As

use of mainly strong caking coke owing to the limitation of cokeshown in the Figure 1, the existing coke production process isstrength, significant energy consumption due to the characteristics ofdivided into three stages along the process flow, namely 1) rapid

the process, as well as environmental issues. Coke ovens in Japan

heating of coal, 2) rapid carbonization, and 3) medium-to-low

have reached their average lifespan of approximately 30 years, andtemperature coke reforming. Development was carried out of aare entering a replacement phase. Given this requirement to replace

revolutionary process with overall balance that pursued thethe ovens, there is a need to develop an innovative, next-generation

functions of each stage to the utmost.

coke production technology that has the flexibility to handle coalresources, that is energy efficient, that has excellent environmental

Currently, SCOPE21 is just one large development project for new

characteristics, and that is also highly productive. Responding tocoke processes in the world, and it is hoped that it can be put tothese needs, a team developed a new coke process.

practical use.

Hot briquetting machine
Plug flow conveying system

Stationary charge unit

Tightly sealed oven door
Pneumatic
pre-heater

Emission freecoke extrusion

Coke upgrading

Carbonizing chamber

Coarsecoal

Fine coal
Stack

High heat conductivity brickPressure control(750-850OC)

Fluidized-bed dryer

Power plant

Smokelessdischarge

Steam

Regenerator

CoalFoundation

Fuel

Hot blaststove

Coke (150-200OC)
Sealed coke conveyor(750-850OC)
Blast furnace

Flue gas

Fig. 1 Process flowchart of next-generation coke oven process

2. Development objectives and technology to be developed
current level, the study significantly reduces the carbonizing time(1) Increasing the ratio of noncaking coal use to 50%
With the aim of increasing the ratio of noncaking coal use to

by increasing the thermal conductivity of the carbonizing

50%, a level that is currently only approximately 20% (noncaking

chamber wall and by discharging the material at temperaturescoal is not the most suitable material for coking), the study

lower than the normal carbonization point, (medium-to-low

develops the technology to increase the bulk density of charging

temperaturecoal through the improvement of caking properties utilizing thecarbonization temperature is compensated for by reheating in the

rapid heating coal technology and through a process to form thecoke dry quenching unit (CDQ) to secure the product quality.

fine coal powder.

(3) Reducing NOx generation by 30% and achieving smokeless,(2) Increasing productivity threefold

odorless, and dustless operation

carbonization).

The

resultinginsufficient

Full-scale prevention of generation of smoke, odor, and dust

With an aim to increase the productivity threefold relative to the49Clean Coal Technologies in Japan
during coke production is attained through the sealed

reduced by 20% through 1) the increase in the temperature totransportation of coal using a "plug transportation" method, thestart the carbonization by pre-heating the charging coal to a highsealed transportation of coke, and the prevention of gas leaks

temperature, 2) the reduction in carbonization heat by reducing thefrom the coke oven by applying intra-furnace pressure control.

discharging temperature, 3) applying medium-to-low temperature

Furthermore, the improved combustion structure of the coke ovencarbonization, and 4) the easy recovery of sensible heat from thereduces NOx generation.

generated gas and combustion flue gas owing to the scale(4) Energy savings of 20%

reduction of the facilities, resulting in increased productivity.

The amount of energy necessary to produce coke is to be
3. Progress and development results
The project was conducted as a joint effort between Japan Coal
Energy Center, and the Japan Iron and Steel Federation. A pilot
plant (6 t/hr) was constructed at Nippon Steel Corp.’s Nagoya
Works, (See Photo 1), and test operations were conducted.

Energy Savings and Economic Evaluation
The SCOPE21 process is composed of innovative technologies,
enabling the effective use of coal resources, energy savings,
and environmental enhancements. As a result, it has great
economic advantages over the conventional process.
Reduction of construction costs
Pretreatment

Common equipment

Total

Conventional

89

---

11

100

SCOPE21

40

25

19

84

Construction costs
Reduction of 16% by greatly reducing the number ofcoke ovens even while expanding the coal pretreatment
plants and environmental protection measures.
Coke production costs
Reduction of 18% by increasing the poor coking coalratio and decreasing construction costs even while
increasing electricity and fuel gas consumption in
the coal pretreatment plant.

Energy savings: Consumption evaluation

Reduction of coke production costs
100

800

Energy consumption (Mcal/t-coal)

Energy savings
Reduction of total energy use by 21% due to theadoption of a pretreatment process with the direct
heating of coal and a high-efficiency coke oven witha heat recovery system.

Photo 1 Pilot plant

Power
Fuel gas

70
600

CDO
recovered271

133

Coke Production cost (%)

Coke oven

CDO
recovered
277

400
600
200

Total
399

460
Total
316

80

Variable
47
Variable
38

60

40
Fixed
53

20

0

Fixed
44

0

Conventional

SCOPE21

Conventional

SCOPE21

SCOPE21 Development schedule
1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

Survey and study

Core technology development

Core technology
combination test
Disassembly andinvestigation

Construction
Pilot plant study

Test operation

4. Issues and feasibility of practical application
Although there has been progress made in the development oftechnology will be introduced to these aging coke ovens, though

furnace repair technology, coke ovens in Japan continue to age

its introduction will be influenced by economic conditions.

and thus still need to be replaced as scheduled. The developed

Reference

1) Kunihiko Nishioka et al., Lecture papers at the 12th Coal Utilization Technology Congress, Tokyo, pp.1-2., November 1, 2002.

50

Part 2 CCT Overview
Iron Making and General Industry Technologies (Iron Making Technologies)

3A5. Coke Dry Quenching Technology (CDQ)
Outline of technology

1. Overview
Overview of CDQ (Coke Dry Quenching) system

After it has cooled to approximately 200oC, the coke is ejected

The coke oven consists of plate-like carbonization chambers

from the bottom, while the circulating gas that has been heatedalternately arranged in a sandwich form to achieve higher thermal

to 800oC or higher generates high-temperature and high-efficiency in carbonization.

pressure steam in the boiler. The gas is purified by a dust

Raw material placed in the carbonization chambers is heated to acollector and then sent back to the chambers for recycling. The

temperature between approximately 1100 and 1350oC through thegenerated steam is used as process steam or for power

combustion of blast furnace gas in the combustion chambers,

generation.

which are located on both sides of the carbonization chambers
Red-hot coke
Processing capacity: 135 t/hr
Temperature: Approx. 1,050oC

beyond the refractory brick. The heated raw material is not
exposed to air for approximately 12 to 14 hours to allow

Energy recovery balance

Boiler inlet gas
temperature:
Approx. 980oC

carbonization to proceed. In this process, the fixed carbon
contained in the raw material fuses and solidifies to become redhot coke in the lower section of the carbonization chambers. The
volatile component in the raw material vaporizes and decomposes,

Process steam:Approx. 77 t/hr
(6.28 MPa, 485oC)

CDQ
boilerbecoming gas. After escaping from the coke surface, the gas is
CDQ
chamberscollected through a pipe located in the upper section of the

Feed
water

carbonization chambers. When carbonization is complete, the redo

hot coke (approximately 1,050 C) is discharged from the cokeoven and then carried to the top of the chambers. The coke is thenTemperature ofdischarged coke:
Approx. 200oC

fed to the chambers and while it descends through the chamber, iscooled with circulating gas blown from the bottom of the chamber.
Sample CDQ operating data

Chamber inlet gas
temperature:
Approx. 130oC

Boiler outlet gas
temperature:
Approx. 180oC

CDQ plants
56t/hrCapacity

Company

Works

Targetfurnaces

Coke processing
capacity (t/hr)(units)Steam(t/hr)

PlantsPressure(kg/cm2)

Nippon SteelOita

No. 1, 2

190 (1)

112.0

95

520

Oct. 1988

Oita

No. 3, 4

180 (1)

92.5

93

520

Aug. 1985

YahataNo. 4, 5

175 (1)

120.0

75

495

Feb. 1987

106 (1)

65.0

117

525

Sept. 1985oCoke charge temperature

1000-1050 C

Coke output temperature

200oC

Temperature(oC)

Put into
service

Gas inlet temperature

170oC

Gas outlet temperature

800-850oC

NagoyaNo. 1, 2

Steam generation

25t/hrNagoyaNo. 3

96 (1)

65.0

117

525

Jul. 1995

Steam pressure

40kgf/cm2

NagoyaNo. 4

129 (1)

71.4

117

525

Feb. 1982

Steam temperature

440oC

KimizuNo. 1, 2, 3

110 (3)

60.0

95

520

Oct. 1982, Aug. 1983

Total gas volume

84,000Nm3/hr

KimizuNo. 4, 5

170 (1)

108.0

95

520

Jan. 1988

Hokkai Steel

Muroran

No. 5, 6

108 (1)

56.5

64

490

Jul. 1981

JFE Steel

East Japan No. 5

100 (1)

50.0

52.5

436

Apr. 1981

56 (3)

30.0

25.0

228

Jan. 1977

70 (5)

39.0

20

280

Sept. 1976

Nippon Steel
ChemicalComparison of CDQ coke quality
Wet quenching(Chiba)Dry quenching

No. 6, 7

Water content (%)

2-5

0.1-0.3

East Japan No. 1

Ash content (%)

11.35

11.39

(Keihin)Volatile components (%)
Average particle size (mm)

0.50
65

0.41
55

Powder rate (after cut) (-15 mm%)

1013Porosity (%)

49

48

DI 15 (%)

83.5

85.5

DI 15 (%)

150

12.9

17.9

Coke strength after small reaction (%)

50

52

150

Sumitomo Metal
Industries

Composition of circulating gas
Gas

CO2

CO

H2

N2

Concentration (%) 10-15

8-10

2-3

70-75

Kansai Cokeand Chemicals
Nakayama Steel Works

51

70 (3)

39.0

20

280

Jul. 1979

West Japan No. 3, 4

100 (2)

64.9

99.0

330

Aug. to Sep. 1983

(Kurashiki) No. 5, 6

130 (1)

85.0

99.0

330

Jan. 1986

West Japan No. 4

125 (1)

69.0

105

540

Apr. 1986(Fukuyama) No. 5

200 (1)

116.5

85

520

Feb. 1990

No. 3

185 (1)

111.7

86

523

Jan. 1997

195 (1)

100.0

105.0

545

Mar. 1986

No. 2AB

150 (1)

65.0

105.0

545

Jan. 1984

No. 2

Kagoshima No. 1ABCD

No. 2CD

130 (1)

65.0

105.0

545

Nov. 1981

Wakayama

No. 6

100 (1)

60.0

102

540

Apr. 1994

Kakogawa

No. 1, 2

140 (1)

84.0

112.0

556

Jun. 1987

No. 3, 4

150 (1)

98.0

112.0

556

Oct. 1998

No. 2

58 (1)

31.0

65

490

May 1991

Funamachi

Clean Coal Technologies in Japan

2. Features of CDQ system

The red-hot coke extruded from the coke oven is cooled by spraying it with water. The water used for cooling

Conventional
systemis vaporized and released into the atmosphere. An issue with this conventional system is the energy loss
when the thermal energy of the red-hot coke is converted into heat that is vaporized and released unused.
Another drawback is that the conventional system also produces airborne coke dust.

In the CDQ system, the red-hot coke is cooled by gas circulating in an enclosed system, thereby preventing

CDQ
systemthe release of airborne coke dust. The thermal energy of the red-hot coke, which is lost in the conventional
system, is collected and reused as steam in the CDQ system. This technology uses less fossil fuel andresults in lower CO2 emissions, thereby contributing to the prevention of global warming.

Crane

Charger
Power plants

Primary dust catcher
Pre-chamber

Steel works
Boiler

Cooling chamber

Chemical plants

Water pre-heater
BucketEjector
Secondary dust catcher
Gas recirculating fan

Belt conveyor

CDQ process flow
3. Dissemination of coke dry quenching (CDQ) systems
CDQ systems have been installed in many steel works and coke

Reduction of CO2 emissions (expected energy conservation:
heat collected from generated steam = 604.3 Tcal/year)

ovens in Japan as energy-efficient, environmentally-friendly
technology.

Scenario

Through NEDO model projects, the effectiveness of CDQ has also

CO2 emissions(t-CO2/year)

been recognized in China. The Chinese government specified CDQ
technology as one of the targets in the Tenth 5-year plan in 2000.

CO2 emissions from CDQ project

1,771,569

Baseline CO2 emissions

1,908,311

Steel works in Hanfang, Beijing, Chengde and Hangzhou havealready introduced Japanese CDQ systems.

Expected reduction of CO2 emissions

4. Future prospects
The Asian region is expected to continue increasing its production of
crude steel. Efforts to introduce CDQ are being made in China andIndia. CDQ is an established technology that can help Japan toachieve its Kyoto Protocol target via the use of CDM projects.
52

136,742

Part 2 CCT Overview
Iron Making and General Industry Technologies (General Industry Technologies)

3B1. Fluidized-bed Advanced Cement Kiln System (FAKS)
Technology overview

1. Features
The Fluidized-bed Advanced Cement Kiln System (FAKS)
efficiently combusts low-grade coal, significantly reduces NOx
emissions, and increases the heat recovery efficiency between
solids and gases discharged from the process. This isaccomplished by leveraging the advantages of the fluidized-bed
process, including the combustion efficiency, and the heattransfer efficiency, as well as the particle dispersion andgranulation features. Thus, the ultimate objectives of thedevelopment are to contribute to global environmental
conservation, energy conservation, and to fulfill demands forvarious types and/or special grades of cement.

Cement clinker

Fluidized-bed kiln

Rotary kiln

Photo 1 Clinker produced from a fluidized-bed kiln

Photo 2 Overview of 200 t/day plant

2. Technology overview
A FAKS includes a fluidized-bed cement kiln and a two-stage

Gas

cooler. The fluidized-bed cement kiln reduces the raw material toa specific size for melting it into high quality cement, and then

C1 Cyclone

sinters the granulated raw material at a high temperature. The
two-stage cooler combines a quenching cooler and a packedbed, slow-cooling cooler to increase the heat recovery efficiency.

Raw material
For C2 Cyclone

The most important technology in the system is the granulation

Air lock damper

control technology. Compared with conventional technology,
which required that seed clinker be fed from the outside andwhich required control of the granulation process thus allowing
high temperature raw material powder to adhere and accumulate

FCK: Fluidized-bed
cement kiln

to the seed clinker, FAKS employs a first-ever "self-granulation"
process. Self-granulation is the process where granule cores are

Pulverized coal

generated through the agglomeration of a portion of the raw
material, allowing the rest of the raw material to adhere and grow

Air

PBC: Packed-bed
coolerFBQ

on the core in order to control granulation. The fluidized-bed
cement kiln furnace integrates two major technologies to control

FBQ: Fluidized-bed
quenching coolerAirthe granulation: a raw material injection unit, and a bottom
classification and discharge unit.
Air

Cement clinker

Fig. 1 FAKS process flowchart

53

Clean Coal Technologies in Japan

3. Demonstration site and application
1) 200 t/day demonstration[1] Demonstration site: Sumitomo Osaka
Cement Co., Ltd.’s Tochigi plant

Bottom classifying
discharge system

Fluidized-bed cement kiln
Raw material

Primary
classifying[2] Application: Cement production[3] Development period: 1996 to 1998

Air2) 1,000 t/day demonstration

Secondaryclassifying[1] Demonstration site: Shandong Paoshan Biological Building

Raw material
injection device

Materials Co., Ltd.
Liubo City, Shandong Province, China

Special distributor
with center cone

[2] Application: Cement production[3] Development period: 2005 to 2007

Air
Clinker granules

Fig. 2 Key technology

4. Demonstration site and application
A basic study of FAKS technology was originally launched inoperation. The basic planning and design of a 200 t/d plant were1984 as a voluntary project by Kawasaki Heavy Industries, Ltd.

jointly undertaken by Japan Coal Energy Center, and the Japanand Sumitomo Osaka Cement Co., Ltd. Based on the results of

Cement Association in April 1993. This scaled-up plant was put

the study, research and development have been sponsored since

into test operation for commercialization in February 1996. After1986 under a Coal Production and Utilization Technology

the system was validated, test operations of the plant were

Promotion Grant project of the Agency of Natural Resources andcompleted at the end of December 1997.

Energy of the Ministry of International Trade and Industry. In June

NEDO also launched a joint demonstration project for a 1,000 t/dof 1989, a 20 t/d pilot plant was constructed jointly by Japan Coal

FAKS plant at Shandong Paoshan Biological Building Materials

Energy Center, Kawasaki Heavy Industries, Ltd., and Sumitomo

Co., Ltd. in Liubo City, Shandong Province, China, as an

Osaka Cement Co., Ltd. The plant was subsequently put into test

International Coal Utilization Project in May 2005.

5. Issues
A performance comparison between the conventional technology

below. FAKS is expected to be commercially adopted as an

and FAKS for a 1,000 t/d commercial plant is shown in the Table 1

innovative, alternative cement production technology.

Table 1 Comparison of environmental improvement effects of FAKS vs. a rotary kiln type process at a 1,000 t/d plant
Discharge quantity
NO2
1% N and10% O2 content in coal
Emissions Rotary Kiln & AQC FAKS
CO2*
depends on electric power
and fuel consumption

Rotary Kiln & AQC

FAKS

Emissions (mg/Nm3)

708

476

Annual emissions(tons-NO2/year)

341

233

Emissions (g/Nm3)

245

220

Annual emissions(tons-CO2/year)

118x103108x103tons-clinker/day

1,000

1,000

tons-cement/day

1,050

1,050

330

330

3,411x103

2,993x103

Basis of calculation
Production capacity
Annual operating timedays/year

Heat consumption

kJ/ton-clinker

Power consumption

kWh/ton-clinker

27

36

Exhaust gas specific quantity

Nm3/kg-clinker

1.46

1.49

Lower calorific value of coalkJ/kg-coal

25,11625,116*Based on IPCC: Guideline for National Greenhouse Gas Inventories, Reference Manual Carbon Emission Coefficient/Basic Calculation;
Carbon Emission Factor = 26.8 tC/TJ, Fraction of Carbon Oxidized = 0.98

Reference

1) Isao Hashimoto, Tatsuya Watanabe, et al., Development of Fluidized Bed Advanced Cement Kiln Process Technology (Part 9),
The 8th Coal Utilization Technology Congress, Japan, September 1998.
54

Part 2 CCT Overview
Iron Making and General Industry Technologies (General Industry Technologies)

3B2. New Scrap Recycling Process (NSR)
Research and development: Japan Coal Energy Center; Nippon Sanso Corp.; and JFE Steel Corp.
Project type: Coal Production and Utilization Technology Promotion Grant
Period:1992-1997 (6 years)

Technology overview

1. Background
In Japan, approximately 30 million tons of iron scrap are recycled

melting process. In response, the NSR process employs technology

annually, and most is melted in arc furnaces, which consume athat melts metals such as iron scrap utilizing high-temperaturesignificant amount of electric power. The energy efficiency of an arc

energy from the direct combustion of pulverized coal by oxygen

furnace is as low as approximately 25% (converted to primaryinstead of electric power. The NSR process was developed with theenergy, taking into account power generation and transmission

objective of significantly increasing the energy efficiency of theefficiency). Given this, there is a need for a more energy-efficientmelting process relative to that of conventional technology.

2. Development timetable
Development was promoted by a joint team from Japan Coal

efficiency melting. The study began with a batch smelter. With theEnergy Center, Nippon Sanso Corp., and NKK Corp. (now JFE

results of the batch smelter, a continuous melting furnace was

Steel Corporation). The main subjects of development were thedeveloped, with the objective of improving the energy efficiency.

furnace structure and the burner arrangement to attain highTable 1 Development timetable
1992

1993

1994

1995

1996

1997

SurveyBatch-furnace

Bench scale (1 t/batch)
Pilot plant scale (5 t/batch)Continuous furnace (pilot plant scale: 6 t/hr)

3. Overview of process and results of study
Figure 1 shows the process overview of the continuous melting

Using the above-described system, even slow-burning pulverized

furnace. The melting furnace consists of three sections: melting,coal can be rapidly combusted, with efficiency similar to that ofbasin, and holding, each of which functions separately. Eachliquid fuels, such as heavy oil. Raw materials fed from the top of

section has a pulverized coal oxygen burner. The oxygen

the furnace are directly melted by the burner in a shaft-shapedosupplied to the burner is preheated to temperatures of 400-600 C

melting section in the lower part of the furnace. The melted raw

by an oxygen preheater to combust the pulverized coal.

material flows through the basin section and enters the holding
Bag filter
Flue gas

Blower
Raw material
Oxygengenerator

Open/close damper

Burnercontroller

Slide gate

Oxygen preheater

Pulverizedcoal tank

Pulverized coal
oxygen burner

Pulverizedcoal charge
unit
TuyereNitrogengenerator

Molten steel

Fig. 1 NSR process flowchart

Fig. 2 Pilot plant (6t/hr)
55

Clean Coal Technologies in Japan

section. The molten steel is soaked in the basin section. The

Furthermore, the process achieved highly superior results relative

carbon content of the molten steel in the basin section can beto the conventional process from an environmental perspective,

controlled by injecting powder coke into the furnace. The holding

such as a significant suppression of dust (excluding the ash insection stores the molten steel for a specified period, and rapidly

pulverized coal) and of dioxins, due to the control of theheats the molten steel to approximately 1,600oC, and then taps

intrafurnace atmosphere.

the molten steel through an EBT system. Molten steel agitation
gas is injected from the bottom of the respective furnaces to thebasin section and the holding section to accelerate the heattransfer from flame to molten steel, thereby enhancing the slag-

1600
Coke

metal reaction. All the combustion gas coming from the individual
1400

sections passes through the melting section, and is vented from
Melting energy (Mcal/T)

the furnace top after being used to preheat the raw material in
the melting section. The raw material is continuously fed from thefurnace top and melted in the furnace. Tapping from the holding
section is conducted intermittently.
The process effectively utilizes the heat transfer characteristics ofoxygen burners, and achieves high-efficiency melting. Figure 3
shows a comparison of melting energy between the NSR process

Oxygen

1200
1000
800

Electric power

600
400
Pulverized coal

200

and the arc furnace. Electric power (oxygen is also added0

because it is produced by electricity) is included in the primary

EAF(380Wh/T)

energy and includes power generation and transmission losses.
Compared with a standard arc furnace, melting energy was

NSR

Fig. 3 Comparison of melting energy

reduced by 40%, dramatically improving energy efficiency.

4. Toward practical application
The study team completed the design for actual scale facilities.

power melting technology, which, even globally, is quite rare, andDue to the influence of the current poor economy in the electricbecause of the strong advantage of being unaffected by the

furnace industry, however, the process has not been brought into

electric power infrastructure, the study team continues to makepractical application. Nevertheless, since the process is a non-efforts toward commercialization in Japan and abroad.
Fig. 4 Schematic for commercial scale plant (50 t/hr)

Fig. 4 Schematic for commercial-scale plant (50 t/hr)

References

1) Hiroshi Igarashi, Toshio Suwa, Yukinori Ariga, and Nobuaki Kobayashi: ZAIRYO TO PROCESS (Materials and Processes), Vol. 12, No. 1, p. 135, 1999.
2) Hiroshi Igarashi, Nobuaki Kobayashi, and Hiroyuki Nakabayashi: Technical Bulletin of Nippon Sanso Corp., (19) pp. 30-37, 2000.

56

Part 2 CCT Overview
Multi-purpose Coal Utilization Technologies (Liquefaction Technologies)

4A1. Coal Liquefaction Technology Development in Japan
Technology overview

1. Background of coal liquefaction technology development
Since the Industrial Revolution, coal has been an important

History of NEDOL Processsource of energy. Coal consumption surpassed that of firewood

Year

Publications, events, landmarks, etc.
Three liquefaction
processes

and charcoal for the first time in the latter half of the nineteenth
century, making coal a major source of energy. In Japan, coal

1979

Sunshine Project started (July 1974)
Research on three liquefaction processes begins.

also became a primary energy source in the twentieth century. In

1980(1) Solvent Extraction Process (2) Direct Hydrogenation Process (3) Solvolysis Process

the 1960s, however, coal’s preeminence gradually faded as it was

1981

NEDO established (Oct. 1, 1980), Coal Technology Development Officeassumes responsibility for three liquefaction processes.

replaced by easier-to-use oil. It was after the oil crises of 19731982

and 1978 that coal was thought of highly once again. With the oil

1983

crises as a turning point, the development of oil-alternative

1984

energy, particularly coal utilization technology, came into the1985

spotlight amid calls for a diversification of energy sources. During

First interim report (the same as the Joint Council report mentioned below)(Aug. 1983) Unification of three liquefaction processes recommended.
NEDO begins conceptual pilot plant planning (three processes and a proposal for their unification)
Conceptual designof 250 t/d

Unification of three processes/development of NEDOL Process-NCOL established (Oct. 1, 1984)

250 t/d design

PDU-based (1 t/d of Sumitomo Metals-Hasaki)
PSU-based research (design)started (1 t/d of Nippon Steel-Kimitsu)(around 1985).
PSU operation research commenced (1987).

1986

that time, the liquefaction of coal, which had been positioned as

Basic concept
Conceptual design
preparation

1987

the strongest oil-alternative energy contender because of huge
1988

coal reserves, was undergoing development in many countries.
1989

Research in Germany and the United States involved pilot plants

150 t/d pilot plant started.

(Downscaled from 250 t/d to 150 t/d.)

150 t/d design

1990

with the capacity to treat hundreds of tons of coal per day. In

1991

Japan as well, development of coal liquefaction technology was

1992

being promoted under the Sunshine Project mainly by the New
Energy and Industrial Technology Development Organization

1993(NEDO). Despite being a decade or so behind Germany and the

1994

United States, slow but steady development progress in Japan1995

led to the successful completion of a 150 t/d-scale pilot plant for1996

the liquefaction of bituminous coal in 1998. This drew Japan1997

equal with Germany and the United States and also established1998

Construction

Review of total project costs toward reduction(April 1991, agreed upon at operation meeting.)-Kashima Establishment opened (Oct. 1, 1991).
-Ground-breaking ceremony for pilot plant held (Nov. 25, 1991),
NEDO s Coal Technology Development Office reorganized into CCTC (Oct. 1992).
Total project costs reconsidered to be clearly defined(Nov. 1992). Set at 68.8 billion yen.
New Sunshine Project begins (1993)

Operation

Recommendations to the 48th Subcommittee Meeting for Coal Conversion (March 1995)
Period of research extended for completion (March 31, 1999)-Research Center inaugurated (June 24, 1995)-Ground-breaking ceremony for pilot plant (July 10, 1996)-Coal trial run (Nov. 26-29 1996, Feb. 25-27 1997)-Coal trial run-1 (March 26, 1997)-Coal trial run-7 (Sept. 9, 1998)

state-of-the-art coal liquefaction technology. Coal-producing
countries, such as China and Indonesia, have also expressed

1999

strong interest in the commercialization of coal liquefaction

2000

Cleaning,
etc.
Research on dismantlement
Removaltechnology, with high expectations for its future development.

2001

Total coal feeding time of 6,062 hours or 262 days (excluding trial runs)
Longest coal feeding continuous run time (1,921 hours)-Operation completion ceremony held on Sept. 29, 1998.
-Pilot plant operation completion report meeting held
(Dec. 1, 1998) at Gakushi Kaikan hall.
-Pilot plant operation research completed (March 31, 2000).

2. History of coal liquefaction technology development in Japan
2.1 Dawning of coal liquefaction technology development

Process was introduced into Japan upon its announcement in

Between around 1920 and 1930, the South Manchurian Railway

Germany in 1935 and, in 1937, the construction of a plant

Co., Ltd. started basic research on coal liquefaction using thecommenced in Miike. This oil synthesis plant was completed in

Bergius Process, and around 1935 initiated operation of a bench-

1940, with an annual production capacity of 30,000 tons of coalscale PDU (process development unit) plant. Based on thisoil. Under the backdrop of war, production of synthetic oil was

research, a plant with annual production capacity of 20,000 tons

continued until the end of World War II.

of coal oil was built at the Wushun coal mine, China, and

2.2 Post-war research on coal liquefaction

operated until 1943. In the meantime, Korean Artificial Petroleum

Immediately after the war, the U.S. Armed Forces Headquarters

Co., Ltd. succeeded, between 1938 and 1943, in the continuous

banned coal liquefaction research, alleging that it was military

operation of a direct coal liquefaction plant capable of treating

research. In 1955, coal liquefaction research was resumed at

100 t/d of coal at its Agochi factory. The production of coal oil atnational laboratories and universities. This was not, however,both of the above-mentioned plants was suspended at the

research on coal oil production but the production of chemicals

request of the military so that the plants could be used for thefrom the high-pressure hydrocracking of coal. This researchhydrogenation of heavy oil or to produce methanol. Around 1930,

continued until around 1975. The Sunshine Project was

besides the direct coal liquefaction method (Bergius Process), a

inaugurated in 1974 on the heels of the first oil crisis,

second process, the Fischer-Tropsch Process, was used as anencouraging efforts to devise liquefaction technology unique toindirect coal liquefaction method to study coal liquefaction

Japan as part of an oil-alternative energy development program.

technology and to produce synthetic oil. The Fischer-Tropsch

Under the Sunshine Project, technological development was
57

Clean Coal Technologies in Japan

undertaken for three coal liquefaction processes, (Solvolysis,

2.4 Bituminous coal liquefaction technology development

Solvent Extraction, and Direct Hydrogenation), to liquefy(NEDOL Process)bituminous coal. The R&D of brown coal liquefaction processes

Bituminous coal liquefaction technology development isbegan at the end of 1980.

described in [4A-2].

2.3 Amalgamation of three coal

2.5 Brown coal liquefaction technology development (BCL

liquefaction processes

Process)

With the oil crises as an impetus, coal liquefaction technology

Brown coal liquefaction technology development is described indevelopment was incorporated for further promotion into the[4A-3].

Sunshine Project based on Japan’s international obligations andthe need for a large, stable supply of liquid fuel, the diversificationof energy sources and the development of oil-alternative energy.
In 1983, NEDO (New Energy Development Organization, now
New Energy and Industrial Technology Development Organization)assembled the R&D results thus far obtained from the threebituminous coal liquefaction processes as follows:(1) Results of Direct Hydrogenation Process: Under certain
reaction conditions, the better the catalyst function, the higher theliquid yield rate.
(2) Results of Solvent Extraction Process: Hydrogen offersliquefaction under mild conditions.
(3) Results of Solvolysis Liquefaction Process: To focus on theacquisition of light oil, it is effective to thicken the circulation
solvent. These three processes were amalgamated on thestrength of their features into the NEDOL Process.

(Catalyst)
Coal
Liquefaction reaction
Solvent

Separation

Coal oil
Solvent

450OC,150atm
Hydrogen
Solvent hydrogen(Medium to a slightly heavy)

Ni-Mo catalyst

Coal
Liquefaction reaction
Solvent

Separation

Coal oil
Solvent

450OC,250atm
Hydrogen

Coal
Solvent

Ni-Mo catalyst
Degree ofdissolution

SRC(Ultra-heavy oil)
450OC150atm

Deashing

Liquefaction
reaction

Separation

Ash Hydrogen
400OC,150atm

Coal oil
Solvent

Solvent hardening technology

Solvolysis System (PDU)

NEDOL Process
High-performance catalyst (Fe)Coal
Liquefaction reaction

Separation

Solvent

Coal oil
Solvent

450OC,170atm
HydrogenHigh-performance catalyst technology

Direct Hydrogenation System (PDU)
High-performance catalyst (Fe)Solvent hydrogenation technology

Solvent Extraction System (PDU)

Ni-Mo catalyst

Solvent hydrogen(Heavy)Hydrogen[Referential] EOS Process (U.S.)

Coal

Ni-Mo catalyst

450OC, 140atm
Liquefaction reaction

Separation

Solvent, hydrogen

Solvent

Solvent
Hydrogen

Bottom recycle

HydrogenFig. 1 Basic philosophy of NEDOL Process

References

1) Sadao Wasaka: "Bulletin of The Japan Institute of Energy," 78 (798), 1999.
2) "Development of Coal Liquefaction Technology - A Bridge for Commercialization," Nippon Coal Oil Co., Ltd.
3) Haruhiko Yoshida: "Coal Liquefaction Pilot Plant," New Energy and Industrial Technology Development Organization.
58

Coal oilPart 2 CCT Overview
Multi-purpose Coal Utilization Technologies (Liquefaction Technologies)

4A2. Bituminous Coal Liquefaction Technology (NEDOL)
Research and development: New Energy and Industrial Technology Development Organization; Nippon Coal Oil Co., Ltd.
[Sumitomo Metal Industries, Ltd.; Idemitsu Kosan Co., Ltd.; Nippon Steel Corp.; Chiyoda Corp.; JFE Steel Corp.; Hitachi Ltd.; Mitsui Coal Liquefaction Co., Ltd.;
Mitsui Engineering & Shipbuilding Co., Ltd.; Mitsubishi Heavy Industries, Ltd.; Kobe Steel, Ltd.; Japan Energy Co., Ltd.; Sumitomo Metal Mining Co., Ltd.;
Asahi Chemical Industry, Co., Ltd.; Toyota Motor Corp.; Sumitomo Coal Mining Co., Ltd.; Nissan Motor Co., Ltd.; The Japan Steel Works, Ltd.; Yokogawa
Electric Corp.; and The Industrial Bank of Japan, Ltd.]
Project type: Development of bituminous coal liquefaction technology, and development of NEDOL Process
Period: 1983-2000 (18 years)

1. Overview of NEDOL Process development

2. Evaluation of NEDOL Process

The conceptual design of a 250 t/day pilot plant began in

Figure 1 shows the progress of coal liquefaction technology since

FY1984. Owing to changes in economic conditions, however, thebefore World War II, expressed by the relation between thedesign of a 150 t/d PP began in FY1988. As a support study toseverity of the liquefaction reaction and the yield of coal-liquefied

the pilot plant, the operational study of a 1 t/d process support

oil by generation. As seen in Figure 1, the NEDOL Process isunit (PSU) was carried out. The 1 t/d PSU, constructed in FY1988

competitive with the processes in Europe and the United Statesat Kimitsu Ironworks of Nippon Steel Corp., consisted of fourin terms of technology, economics, and operational stability, andstages: coal storage and pretreatment, liquefaction reaction,

thus the NEDOL Process is one of the most advanced processesliquefied coal distillation, and solvent hydrogenation. Over thein the field, reaching a position to shift to commercialization in theten-year period from FY1989 to FY1998, a joint study team fromshortest amount of time.

Nippon Steel Corp., Mitsui Coal Liquefaction Co., Ltd., and

Large

Technology overview

Nippon Coal Oil Co., Ltd. conducted operational studies on nine

Third generation

Yield of coal-liquefied oilcoal grades under 72 conditions. Through the 26,949 hours of
cumulative coal slurry operations, the stability and the overall
operability of the NEDOL Process were confirmed, andoptimization of the process was established. Finally, thenecessary design data was acquired. Construction of the 150 t/dpilot plant was launched in 1991 at Sumitomo Metal Industries,
Ltd.’s Kashima Steelworks (Kashima City, Ibaraki), requiring

NEDOL Process
CC-ITSL Process (U.S.A.)
IGOR+ Process (Germany)First generation
Processes in the ’40s

main facilities: the coal treatment unit, the consisted liquefaction
reaction unit, the liquefied coal distillation unit, the solvent

Severehydrogenation unit, and the hydrogen production unit.

Severity of reaction

Liquefaction/reaction unit

Coal liquefied oil distillation unit
Gas
Separator

Atmosphericpressure
distillation column

Circulation gas compressor
HydrogenSlurry mixer
Hydrogencompressor
Slurry tank

170kg/cm2G(16.7MPa)
450oC

Preheating
furnaceSlurry heatexchanger

Heating
furnace

Fuel

Hydrogen

Fuel

Preheating
furnace

110kg/cm2G(10.8MPa)
320oC

Residue
Solvent booster
pump

Stripper

Kerosene/gas oil distillate
Vacuumdistillation
columnLiquefaction
reactor(3 units)

Separator

Drying/pulverizing
unit

NaphthaHightemperature
separator

Let-down valve
High-pressure
slurry pump

(Hydrogen-donor solvent)

Mild

Fig. 1 Relation between the severity of liquefaction
reaction and the yield of coal-liquefied oil

Iron-based
catalyst

Coal

Coal bin

Processes after the oil crises

Smallnearly five years for completion. The pilot plant consisted of five

Coal preliminary
treatment technology

Second generation

Solventhydrogenation
reactor
Fuel

Solvent hydrogenation unit

Fig. 2 Bituminous coal liquefaction process flowchart
59(Heavy distillate)Clean Coal Technologies in Japan

3. Features of NEDOL Process
The NEDOL Process is a coal liquefaction process developed

core process stages; andexclusively in Japan. The process has integrated the advantages(4) applicability to a wide range of coal ranks, ranging from sub-of three bituminous liquefaction processes (Direct Hydrogenation

bituminous coal to low coalification grade bituminous coal.

Process, Solvent Extraction Process, and Solvolysis Process),
Catalysts

thus providing superiority in both technology and economics. The
Liquefaction catalyst

Hydrogenation catalyst

48.2
51.0
0.8
Other (wt%)
Specific surface area (m2/g) 6.1
0.7-0.8
Size of pulverized catalyst [D50]( m)Ni-Mo/ Al2O3
190
0.7
Micropore volume (ml/g)
14.5
Mean micropore size (nm)advantages of the NEDOL Process include:(1) attaining high liquid yield under mild liquefaction reaction

Catalyst composition Fe (wt%)

conditions owing to the iron-based fine powder catalyst and to theS (wt%)hydrogen-donating solvent;(2) producing coal-liquefied oil rich in light distillate;(3) assuring high process stability because of the highly reliable

Catalyst composition Fe (wt%)

Specific surface area (m2/g)

4. Typical reaction conditions of NEDOL Process
Liquefaction reaction
Temperature

450 C
170kg/cm2 G
O

PressureType of catalyst

Iron-base fine powder catalyst
Added amount of catalyst 3 wt%(dry coal basis)

Solvent hydrogenation reaction

Slurry concentration 40 wt% (dry coal basis)

Temperature

Slurry retention time

Pressure

60 minGas/slurry ratio
700Nm3/t
Hydrogen concentration in recycle gas 85 vol%320 C
110kg/cm2 G
Ni-Mo-Al2O3
1 hr(-1)
O

Kind of catalyst
LHSV

Gas/solvent ratio
Hydrogen concentration in recycle gas

500Nm3/t
90 vol%5. Pilot plant: Objectives and achievements
Development objectives

TargetAchievements

1. Yield of coal-liquefied oil

For standard coal, 50 wt% or higher
yield of light to medium oils, and 54 wt% of higher total yield

With standard coal, attained 51 wt%
yield of light to medium oils, and 58 wt% of total yield

2. Slurry concentration

40-50 wt% of coal concentration in slurry

Stable operation achieved at 50 wt% of coal concentration in slurry

3. Added amount of catalyst

2-3 wt% (dry-coal basis) of added amount of iron sulfide-base catalyst Operation conducted in a range from 1.5 to 3 wt% of added amount of iron sulfide-base catalyst

4. Continuous operation time

1,000 hours or more for standard coalContinuous operation of 80 days (1,920 hours) achieved with standard coal

5. Range of applicable coal grades

Three coal ranks or more

Operation conducted with a wide range of coalification ranks, namely Adaro coal, Tanitohalm coal, and Ikejima coal

6. Research and development timetable of NEDOL Process pilot plants(Fiscal year)

~1983

1984

1985

1986

1987

1988

250 t/d PP design

1989

1990

1991

150 t/d PP design

1992

1993

1994

1995

1996

Construction

1997

1998

Operation

Core technology research and support study

7. Research and development results
All the acquired data, including the pilot plant data, the basic

Furthermore, the developed materials and new processes areresearch data, and the support study data, were summarized in a

expected to significantly influence development in other industries.

technology package in preparation for practicalapplication. At the Development and Assessment

Central control building
Solvent hydrogenation unit

Committee Meeting for Bituminous Coal Liquefaction
Technology in the Assessment Work Group of theIndustrial Technology Council, held on December 22,

Fuel tank

Liquefaction reaction unit

1999, the NEDOL Process was highly evaluated:
Coal-liquefied oil distillation unit

"The NEDOL Process is at the highest technology

Coal preliminary treatment unit

level in the world, and has reached the stage whereworldwide

diffusionisexpected." Thus,

Hydrogen production unit

thedevelopment of coal liquefaction technology in Japan

Storage tanks

has already exited the research and development
stage and entered the practical application stage.

Fig. 3 NEDOL Process pilot plant (150 t/d)References

1) Sadao Wasaka: "Bulletin of The Japan Institute of Energy," 78 (798), 1999.
2) "Development of Coal Liquefaction Technology - A Bridge for Commercialization," Nippon Coal Oil Co., Ltd.
3) Haruhiko Yoshida: "Coal Liquefaction Pilot Plant," New Energy and Industrial Technology Development Organization.
60

Part 2 CCT Overview
Multi-purpose Coal Utilization Technologies (Liquefaction Technologies)

4A3. Brown Coal Liquefaction Technology (BCL)
Research and development: New Energy and Industrial Technology Development Organization;
Kobe Steel, Ltd.; Nissho Iwai Corp.; Mitsubishi Chemical Corp.; Cosmo Oil Co., Ltd.; Idemitsu Kosan Co., Ltd.;and Nippon Brown Coal Liquefaction Co., Ltd.
Project type: Development of Brown Coal Liquefaction Technology; Development of Basic Liquefaction Technology;
Coal Liquefaction International Cooperation Project; and other projects
Period: 1981-2002 (21 years)

Technology overview

1. Background and process overview
Economically recoverable coal reserves are expected to total

As shown in Figure 1, the BCL process has four stages: theabout one trillion tons, about one-half of which are comprised ofslurry dewatering stage, where water is efficiently removed fromlow-rank coal such as sub-bituminous coal and brown coal. Coal

low-rank coal; the liquefaction stage, where liquefied oil

has a larger ratio of reserves to production (R/P) than that of oil

production yield is increased by using a highly active limonite

and natural gas. For the effective utilization of coal, however, thecatalyst

effective use of low-rank coal is essential. Low-rank coal containshydrotreatment stage where the heteroatoms (sulfur-containing

a large amount of water, but unlike bituminous coal and othercompounds, nitrogen-containing compounds, etc.) in the coal-

higher rank coals, has an autoignition property in a dry state.

liquefied oil are removed to obtain high quality gasoline, diesel

Consequently, brown coal liquefaction technology developmentoil, and other light fractions; and the solvent de-ashing stage

has progressed with the aim to use it to contribute to a stable

where the ash in coal and the added catalysts are efficiently

supply of energy in Japan by converting the difficult-to-use low-discharged from the process. In Asian countries, economic

rank coal into an easy-to-handle and useful product, or by using it

growth has steadily increased energy demand, and countries

to produce clean transportation fuels such as gasoline and diesel

possessing low-rank coal resources, such as Indonesia,

oil.

anticipate commercialization of the technology.

Liquefaction stage

andbottomrecyclingtechnology;theIn-line hydrotreatment stage
Sulfurrecovery unit

HydrogenSulfurRecycle gas
Recycle gas

Slurry dewatering stage

Off gaspurification unit

Product gas(Fuel gas)

ReactorCoal(Raw brown coal)Hydrogenatedlight oil

Water
Evaporator
Fixed-bedhydrogenation
reactorDistillation column

Hydrogenatedmedium oil

Solvent de-ashing stage

Preheater
Slurry charge pump

Catalyst supply unit

Settler
CLB (heavy oil)separator
Sludge

CLB recycle

CLB

Solvent recycle
DAO (deashed heavy oil) recycle

Fig. 1 Flowchart of BCL process

61(Boiler fuel)in-lineClean Coal Technologies in Japan

2. Development objectives and developed technology
A pilot plant (Photo 1) study conducted under thegovernmental cooperation of Japan and Australia
set the following technical targets:(1) High liquefied oil production yield: 50% or
greater(2) Long-term continuous operation: 1,000 hours
or greater(3) High deashing performance: 1,000 ppm or
less(4) Establishment of new slurry dewatering
process. Through four years of operation andstudy (1987- 1990), all of the above targets wereachieved. Furthermore, scale-up data necessary
to construct commercial liquefaction plants andexpertise on plant operation were obtained
through pilot plant operation. During the study
period, (the 1990s), however, oil prices were low

Photo 1 Fifty t/d Pilot plant (Australia)

and supplies were stable worldwide. Thus, further
improvements in the economics of the coal liquefaction processcatalytic activity through bottom recycling technology; an in-line

were vequired and cleaner liquefied oil was demanded owing tohydrotreatment technology that significantly improves the quality

increased environmental concerns. Accordingly, a bench-scaleof coal-liquefied oil; and various improvements for increasing

plant (0.1 t/d) in Kobe Steel, Ltd.’s Takasago Works wasoperational reliability. Through the development work, an

constructed to conduct a study for improving the process. Results

improved BCL process (Improved Brown Coal Liquefactionof the study included the development of: a limonite catalyst, anProcess: refer to the flowchart on the preceding page) that

extremely active catalyst compared to existing liquefaction

significantly

catalysts, and one possessing superior handling properties, suchenvironmental compatibility of the brown coal liquefaction

as excellent crushing characteristics; a method to maintainprocess was established.

improves

theeconomics,

reliability,and

3. Progress and development results
On the basis of a memorandum of understanding on cooperativeIndonesian engineers through technical training and the supply ofcoal liquefaction research between the Agency for theliquefaction testing equipment. In 1999, the study team selected

Assessment and Application of Technology of Indonesia and thethree candidate sites for a liquefaction plant in Indonesia, andNew

Development

carried out a feasibility study on coal liquefaction, including an

Organization, a study team carried out surveys and liquefaction

economic evaluation. The feasibility study revealed that coaltests of low-rank coal in Indonesia beginning in 1994, in additionliquefaction would be economically feasible at a given oil price.

EnergyandIndustrial

Technology

to screening candidate coals for liquefaction. Furthermore, theteam endeavored to increase the technical abilities of the

4. Issues and feasibility of practical application
Due to steady economic growth, energy demand in Asianenergy security of Japan, brown coal liquefaction technology thatcountries is rapidly increasing. Since the stable supply of energy

utilizes low-rank coal will play an important role.

from Asian countries to Japan significantly contributes to theReferences

1) Shunichi Yanai and Takuo Shigehisa: CCT Journal, Vol. 7, p. 29, 2003.
2) Report of the Results of the International Coal Liquefaction Cooperation Project, Cooperative Study of Development of Low Grade
Coal Liquefaction Technology, 2003.

62

Part 2 CCT Overview
Multi-purpose Coal Utilization Technologies (Liquefaction Technologies)

4A4. Dimethyl Ether Production Technology (DME)
Research and development: DME Development Co., Ltd., JFE Holdings Co., Ltd., Taiyo Nippon Sanso Corporation,
Toyota Tsusho Corp., Hitachi Ltd., Marubeni Corp., Idemitsu Kosan Co., Ltd., INPEX Corporation, TOTAL S.A. (France),
LNG Japan Co., Ltd., and Japan Petroleum Exploration Co., Ltd. (JAPEX).
Project type: National Grant project of "Development of Technology for Environmental Load Reducing Fuel Conversion" of the
Agency for Natural Resources and Energy of the Ministry of Economy, Trade and Industry
Period: 2002-2006 (5 years)

Technology overview

1. Background and process overview
Dimethyl ether (DME) is a clean energy source and as it

produced by dehydrating methanol. Approximately ten thousand

generates no sulfur oxide or soot during combustion its

tons per year are produced in Japan, and 150 thousand tons per

environmental impact is low. Owing to its non-toxicity and easy

year worldwide. DME’s main use is as a spray propellant. Givenliquefaction properties, DME is easy to handle and therefore canthe above-described superior properties, if DME were to become

be used as a domestic-sector fuel (substitute for LPG),

widely available in large volumes at a reasonable price, DME

transportation fuel (diesel vehicles, fuel cell vehicles), power plant

could be used as a fuel in a wide variety of fields.

fuel (thermal plants, cogeneration plants, stationary fuel cells),
and as a raw material for chemical products. Currently DME is
2. Development objectives and technology to be developed
The objective of this study is the development of a process to

Chemical reaction:(1) 3CO+3H2 CH3OCH3+CO2(2) CO+2H2 CH3OH(3) 2CH3OH CH3OCH3+H2O

directly synthesize DME from syngas (mixture of H2 and CO),(Chemical reaction (1)).
Existing technology produces DME through the dehydration of
methanol, (Chemical reaction (3)). The scale of the plant in actual
operation, however, is rather small, and scaling-up is an issue to100

produce DME as a commercial fuel. In addition, the equilibrium

H2+CO conversion [%]conversion of the methanol synthesis reaction (Chemical reaction(2)) is relatively small, as show in Figure 1. On the other hand,because the methanol synthesis equilibrium limitation can be
avoided in the direct DME synthesis reaction (1), a higher
conversion rate can be achieved.
The reaction formulae relating to the direct synthesis of DME areprovided below. The equilibrium conversions for methanol
synthesis and direct DME synthesis are given in Figure 1. Since(1) 3CO + 3H2

6040(2) CO + 2H2

20

direct synthesis produces the maximum conversion with a syngas

CH3OCH3 + CO2

80

CH3OH

composition of H2/CO=1, the process is suitable for the syngas
produced from coal gasification (H2/CO=0.5-1). The targets of the0.0

development study include the following:

0.5

1.0

1.5

2.0

2.5

H2/CO ratio [-]1. DME production rate: 100 tons/day or greater, syngas total
conversion: 95% or greater, DME selectivity: 90% or greater,

Fig. 1 Equilibrium conversion (280 C, 5Mpa)
O

DME purity: 99% or greater
2. Establishing scale-up technology
3. Optimizing entire system
4. Establishing stable plant operation

63

3.0

Clean Coal Technologies in Japan

3. Progress and development results
The development of the direct synthesis process has been led byconstructed with the aid of METI. This demonstration plant was

JFE. The first step was the search for a direct synthesis catalyst.

completed in November 2003 and is scheduled to have six long-

The second step was a small bench plant (5 kg/day). The third

term continuous operation runs over 2 to 5 months from the end

step was a 5 ton/day pilot plant (Photo 1) constructed with the aidof 2003 to 2006. The total production of the demonstration plantof the Ministry of Economy, Trade and Industry (METI). The fourth

has reached approximately 19,000 tons.

step was a 100 ton/day demonstration plant (Photo 2) also

Photo 1 Five ton/day pilot plant

Photo 2 One-hundred ton/day demonstration plant

4. Issues and feasibility of practical application
DME is already utilized as a fuel on a small-scale in an inland

the future, however, they are expected to switch to coal, whicharea of China. In Japan, activities toward the practical application

has larger reserves than natural gas, as the feedstock. Usingof DME as a fuel are being undertaken by: DME International

natural gas, the CO2 obtained from the CO2 separation column isCo., Ltd., which was established by the same ten companies that

returned to the syngas generation furnace; if coal were to beestablished the DME Development Co., Ltd., aiming to study theused, however, the CO2 would be released into the atmosphere.

commercialization of DME; Japan DME Co., Ltd., which was

When long-term CO2 storage technology is established in theestablished by Mitsubishi Gas Chemical Co., Inc., Mitsubishi

future, the coal-based process will be able to provide purified

Heavy Industries, Ltd., JGC, and Itochu Corp.; and Mitsui & Co.,

CO2 without any additional equipment. In the West, DME has

Ltd. and Toyo Engineering Corp., which adopted the methanol

drawn attention in a wide range of fields as a new fuel. There,

dehydration process. These activities aim to supply DME producthowever, it is expected to be mainly used in diesel vehicles toin 2006. All of them plan to use natural gas as the feedstock,

fully leverage the fact that DME combustion generates no soot.

because natural gas requires only a small initial investment. In

Purge gas

CO2

CO2

35m3 N/h

Non-reacted gas

Natural gas

DME

5t /d

Coal mine methane
Coal
OxygenSteam
Liquid/gas separator

Reaction condition
250-280OC
3-7Mpa750m3 N /h

CO, CO2, H2
Synthesis gas generation furnace

Gas purification column

MethanolDME synthesis reactor

CO2 separation column

DME purification column

0.8t /dFig. 2 Typical process flow diagram of DME direct synthesis from a coal or natural gas plant

References

1) Tsunao Kamijo et al., Lecture papers of The 8th Coal Utilization Technology Congress, Tokyo, pp.194-205, 1998.
2) Yotaro Ohno et al., Preprint for the lectures of the 30th Petroleum and Petrochemical Discussion Meeting, Tokyo, pp. 26-29, 2000.
3) Yotaro Ohno: Japan DME Forum Workshop, Tokyo, pp.113-122, 2002.
64

Part 2 CCT Overview
Multi-purpose Coal Utilization Technologies (Pyrolysis Technologies)

4B1. Multi-purpose Coal Conversion Technology (CPX*)
Research and development: Japan Coal Energy Center; Nippon Steel Engineering Co., Ltd.; JFE Steel Corp.;
Sumitomo Metal Industries, Ltd.; Kobe Steel Ltd.; Ube Industries, Ltd.; Idemitsu Kosan Co., Ltd.;
Nippon Steel Chemical Co., Ltd.
Project type: Subsidized coal production/utilization technology promotion
Period: 1996-2000 (5 years)*Coal Flash Pyrolysis Process: CPX stands for Coal Pyrolysis suffixed with X, indicating diverse products.
Technology overview

1. Technological features
In an attempt to further expand coal’s versatile uses, the aim of

4. Efficient separation of coal ash

this project was to develop multi-purpose coal conversion- Coal ash discharged from gasifier as molten slag and thentechnology with excellent efficiency, economic feasibility, andgranulated with water.

environmental-friendliness, mainly for the purpose of manufacturing

5. Diversified utilization of available products

medium-calorie gas as industrial fuel and liquid products as- Among products, gas can be used as industrial fuel, liquids

feedstocks for chemicals.

(light oil/tar) as feedstocks for chemicals, solid char as fuel or a

The technological objectives were as follows:

reducer, and slag as a raw material for cement.

1. Moderate operational conditions- Heating value of gas produced from the process to approach- A pyrolysis reactor operating at temperatures as low as 600-

approximately 3,500kcal/Nm3.

o

950 C.

- Combined yield of gas and liquid (light oil/tar) 70% or more of- A reaction pressure of less than 1Mpa, much lower than several

coal input.

to tens of Mpa used in the coal liquefaction and hydro-gasification

6. Controllable yield of products

processes.

- A change in pyrolysis temperature (600-950oC) or type of coal

2. High overall thermal efficiency

allows product yields to be adjusted accordingly.

- Flash pyrolysis of coal combined with a partial recycling ofgenerated char to gasify more char, thereby improving thermal
efficiency of the process.
3. Multiple varieties of coal
- Utilizing lower grades of coal, from sub-bituminous to highly
volatile bituminous coal, as primary material to enable highgas/tar yields.

Heat recovery
CycloneTar cooler
Gas purification

Scrubber
Coal

PyrolysisreactorGas

Char
hopperCrushing/drying
Char heatrecovery

Steam

Decanter

Separator

Char gasifier

Tar

Char

Slag
Fig. 1 Process flow diagram
65

Clean Coal Technologies in Japan

2. Summary of technology
This conversion process is characterized by higher overall

product (char) separated at the cyclone is recycled to the charthermal efficiency, achieved with a compact, low-pressure

gasifier and the remainder is offered as a product after heatchar/oxygen gasification system that combines the flash pyrolysis

recovery. Heat is recovered from the gas containing pyrolyzedof coal and the partial recycling of pyrolyzed char to use theproducts until it cools down to approximately 350oC through an

sensible heat of the char gasification gas as a heat source for theindirect heat exchange with thermal oil while tar passes the

flash heating/pyrolysis reaction of pulverized coal (Fig. 1). The

venture scrubber/tar cooler to be recovered. Pyrolysis gas is

entrained-bed coal flash pyrolysis process has been developed tomade available for use as industrial-purpose fuel gas after

not only produce more high-value-added gas and liquid (tar andpurification, such as through light oil (BTX) recovery andoil) with a coke oven gas (COG)-equivalent heating value, but

desulfurization. At the pilot plant (Photo 1), built within the Yawata

also supplies the heat necessary for pyrolysis. Pulverized andWorks of Nippon Steel Corp., tests were conducted mainly with adried coal (of about 50

view to the evaluation/verification of process component/total

m in grain size) is injected into theopyrolysis reactor and mixed with 600-950 C gas and several atm.

system technologies to establish the technological basis for

In a reaction lasting two seconds, the coal is flash

commercialization as well as to obtain data that would aid in theheated/pyrolyzed. Part of the pyrolyzed solid char is recycled todesign of an actual plant (1,000t/d) and to evaluate its economic

the hot gas generation section (char gasifier) to be partially

feasibility. In a period of two years, beginning in 1999, it was test-

oxidized by oxygen and steam, thus allowing an approximately

run ten times in all, achieving a maximum 210 hours of stable,o1,500-1,600 C gas stream, mainly composed of CO and H2, to becontinuous operation. During this period, the aforementioned

generated so that the sensible heat of the gas can be used tofeatures were verified, assuring the controllability of products at

supply heat for the pyrolysis reaction. The pyrolysis reactor

certain pyrolysis temperatures (Fig. 2) prior to completing theemploys an up-flow system where the hot gas generated at thisdata collection process.

gasifier is fed from the lower part of the reactor and, after
pyrolyzed coal is mixed, leaves the system at the reactor’s upper

Pyrolysis product yieldpart together with pyrolyzed products. A portion of the solid

Photo 1 Pilot plantFig. 2 Relationship between pyrolysis product yield and pyrolysis temperature
PDU: 7 ton/day test equipment

References

1) Hiroyuki Kozuru et al., Advanced Clean Coal Technology Int’l Symposium, 2001.
2) Masami Onoda et al., 10th Annual Conference on Clean Coal Technology abstracts, 2000.
3) Shigeru Hashimoto et al., Pittsburgh Coal Conference, 2000.
66

Part 2 CCT Overview
Multi-Purpose Coal Utilization Technologies (Pyrolysis Technologies)

Co-production with Coal Flash Partial Hydropyrolysis
4B2. EfficientTechnology (ECOPRO)
Research and development: Japan Coal Energy Center; New Energy and Industrial
Technology Development Organization; National Institute of Advanced Industrial Science and Technology;
Nippon Steel Engineering Co.,Ltd.; Babcock Hitachi K.K.; Mitsubishi Chemical Corporation
Project type: Subsidized coal production/utilization technology promotion project
Period: 1. Coal utilization next-generation technology development survey, 1996-1999 (4 years)
2. Coal utilization commercialization technology development, 2003-2008 (6 years)

Technology overview

1. Technological objective
Clean coal technology-related development solely focused on a

one reactor, synthetic gas that can easily be converted for use

single industry in pursuit of a single product is reaching its limits

such as in integrated gasification combined-cycle (IGCC) powerin terms of efficiency and economy. This is necessitating thegeneration, indirect liquefaction (GTL), and chemicals, while co-development of innovative technologies that could completely

producing light oil for utilization as a feedstock for chemicals andrevolutionize energy and material production.

fuel.

Efficient Co-production with Coal Flash Partial Hydropyrolysis

The realization of a coal-based cross-industrial composite

Technology (ECOPRO) is a technology that causes pulverized

project, led by the electric power, chemical, and steel industries,

coal to react rapidly under high pressure (2-3MPa) and in awith this technology as its core will hopefully bring a dramatic

moderate hydrogen atmosphere to highly efficiently obtain, from

improvement to total energy utilization efficiency.

2. Technology overview
Figure 1 shows the total process flow of this technology. At thein hydrogen concentration (H2 in hot gas and recycle H2partial oxidation section of a coal flash partial hydropyrolsyis

combined). At that time, hot gas from the partial oxidation section

reactor, pulverized coal and recycled char are gasified withalso functions as a source of the reaction heat required at theoxygen and steam at a pressure of 2-3MPa and at a temperaturereforming section. At the reforming section, a hydrogenationof 1,500- 1,600oC to give hot gas mainly composed of CO andreaction adds H2 to primary pyrolysis, such as tar released from

H2. At the reforming section directly connected through a throat

pulverized coal, changing heavy tar-like matter to light oil. The

to the partial oxidation section, pulverized coal is injectedgas, light oil, and char produced at the partial hydropyrolysis

together with recycled H2 into the hot gas stream from the partial

reactor follow a process where, after char separation at theoxidation section to complete the reforming reaction (partial

cyclone and subsequent sensible heat recovery, synthetic gashydropyrolysis) instantly under the condition of 2-3MPa in(syngas) should be formed by way of oil recovery, desulfurization,pressure, 700-900oC in temperature, and approximately 30-50%

and other gas purification processes. A portion of the syngas is

Decarbonization

Shift conversion to H2
Heat
recovery

SyngasGas
purification

Chemicals

IGCC fuel

GTL fuel

City gas

Chemicals

Fuel for power generation

Reforming section
Coal reforming reaction
Gas

Heat
H2 concentration 30-50%

CoalPartialhydropyrolysis reactor

Char

Heat

Coal
Light oil

Hot gasLight oil

Partial oxidation section

Steam
Slag
Fig. 1 Process flow chart
67

Clean Coal Technologies in Japan

converted into H2-rich gas, in the course of a shift reaction and

The features of this technology include:

decarbonization (CO2 recovery). After pre-heated via a heat

1. High-efficiency: The sensible heat of hot gas generated at theexchange, the gas is recycled to the partial hydropyrolysis

partial oxidation section is effectively used as a source of heatreactor’s reforming section. The final syngas product isrequired at the reforming section, providing high energy

characterized by its main composition of H2, CO, and CH4 as wellconversion efficiency.

as hydrogen-rich contents of H2/CO 1 and is used as a source

2. Flexible productivity: The reforming section temperature, asgas for IGCC, GTL, and chemicals. Light oil is mainly composedwell as the amount of hydrogen injected, can be controlled,of aromatic compounds with 1-2 rings such as benzene andallowing the freedom to change the gas/oil composition andnaphthalene, which have applications for chemical manufacturing

output ratio, thereby flexibly responding to consumers’ needs.

or fuel for power generation.

3. Economy: The cost of producing syngas can be partially offset
by the value of the of co-produced high-value-added oil.

3. Progress and development results
1) Basic partial hydropyrolysis test (1996-1999, 1kg/day)

3) Pilot plant test (2003-2008, 20t/day)Using a small-scale test unit, the pyrolysis behavior of coal under

Tests are being conducted using a pilot plant with a thermallythe target conditions of this technology was reviewed, confirming

self-supportable reactor combined with other ancillary processthat the hydropyrolysis of the primary tar released from the flash

units to enable forecasts for a future demonstration unit (up to

heating/pyrolysis reaction of coal was successful.

1,000t/day).

2) Process development unit (PDU) test (2000-2003, 1t/day
Nippon Steel Engineering Co., Ltd. in-house research)
Using a reforming/partial oxidation-integrated PDU test unit, thebasic performance of a partial hydropyrolysis reactor as the core ofthis technology was evaluated, clarifying the reaction in the reactor.

Table 1 Development subjects for pilot plant tests
Technology to be developed

R&D topics

Verification of the reactionin the partial hydropyrolysis reactor/
establishment of reactor control technology- Quantification of partial hydropyrolysis reactor reaction- Establishment of reactor conditions for optimum transition zone formation- Establishment of high-efficiency gasification (partial oxidation section) operational conditions

Development of process/factor technologies- Establishment of technology to separate/recover char from gas- Establishment of technology to recover heat from gas co-existent with oil

Total system evaluation, etc.

- Establishment of extended continuous operation technology- Establishment of scale-up approach for demonstration unit design

Table 2 Development timetable
2003

2004

2005

2006

Pilot plant test
Design/production/construction work
Testing studies
Disassembly studies
Supporting studies

References

1) H. Shimoda et al., 10th Annual Conference on Clean Coal Technology lecture collection, p. 296, 2000.
2) H. Yabe et al., 2nd Japan-Australia Coal Research Workshop Proceedings, p. 257, 2002.
68

2007

2008

Part 2 CCT Overview
Multi-purpose Coal Utilization Technologies (Powdering, Fluidization, and Co-utilization Technologies)

4C1. Coal Cartridge System (CCS)
Technology overview

1. System overview
The Coal Cartridge System (CCS) collectively imports andmanufacture/supply and combustion bases, in an attempt toblends imported coal on behalf of medium-/small-lot consumers

establish the reliability of CCS in regards to coal blending andwho use several thousand tons of coal per year, but for whom it ismeeting the consumers’ quality requirements. As a result, the firstdifficult to directly import. Through CCS, the imported coal isJapanese CCS center, with a capacity to produce 200 thousand

blended into suitable qualities and supplied to consumers as

tons per year, was built in 1991 and operation of two CCS coal-pulverized coal. This system was subjected, under a 3-year

dedicated boilers commenced.

programstarting

in

1985,

to

demonstration

tests

at

2. Features

3. Technical data

In a typical pulverized coal-fired system, before the coal isGeneral attributes of CCS coal are shown in Table 1.

combusted, it is stored in a stockyard. Next, it is pulverized in a millTable 1 General attributes of CCS coalprior to being fed to a boiler. In CCS, however, the coal is pulverized

Brand
Referential control
Raw coal for mixture
Total moisture Wt%
AR
Heating value kcal/kg*
Moisture Wt%
dry
Ash Wt%dry
Volatiles Wt%
drydry
Fixed carbon Wt%
Fuel ratio
daf
Carbon Wt%
daf
Hydrogen Wt%
daf
Nitrogen Wt%
daf
Oxygen Wt%
daf
Sulfur Wt%
dry
Total sulfur Wt%
dryGrain size -200 meshat a production/supply facility, and all processes are completed withina sealed environment, from loading the coal onto tank lorries todelivery and unloading into consumers’ coal silos after which it is

Ultimateanalysisthen supplied to boilers. This environment-friendly process not only
eliminates the problem of the dispersion of coal dust, but alsoenables smoother operation through easier control of powder flows
and, therefore, fluctuations in boiler loads. CCS provides several

Proximateanalysisbenefits to consumers, like negating the need for a mill or a coal yard
since the coal can now be stored in a silo. It also reduces capital
investments because of the compact equipment configuration, thus
leading to labor savings, as well as a better environment. CCS is, asmentioned above, a pulverized coal utilization system featuring
improved coal handling and a sealed-carriage system.

A
3 kinds
2.9
6490
0.0
12.1
39.6
48.3
1.22
80.30
5.80
1.60
11.80
0.48
0.45
84.5

B
3 kinds
2.8
6480
0.0
12.4
39.5
48.1
1.22
80.00
5.80
1.50
12.40
0.47
0.43
78.9

4. Process flow
Figure 1 shows a process flow diagram and system overview ofPulverized coal collection bag filter

a CCS coal production/supply facility.

Screw conveyor

Raw coal bunker

Magnetic
separator

Mill supply
hopperVolumetriccoal feeder

Chain conveyor

Product
silo

Product
silo

Table feeder

Truck scale

Pulverizer
Fuel gas

Productsilo

Air heater

Sealed gas
blower

KeroseneGas cooler
Fuel air blower

Recycle gas blower

Recycle gas line

Cooling tower
Industrial watertank

Nitrogen generator

Equipment overview
1. One raw coal hopper (20m3)
2. Two raw coal bunkers (400m3)
3. Two pulverizers (25t/hr)

3

4. One bag filter (67,500Nm )3
5. Four product silos (680m )6. Four truck scales
3
7. One nitrogen generator (350Nm )Fig. 1 Process flow of CCS coal production/supply facility
69

tank

Raw coal hopper

Conveyor

Productsilo

C
2 kinds
2.7
6490
0.0
12.1
35.6
50.3
1.41
82.00
5.90
1.50
10.50
0.45
0.41
83.50

Clean Coal Technologies in Japan

4C2. Coal Water Mixture Production Technology (CWM)
Technology overview

1. Coal slurry overview
The fact that coal is a solid causes some challenges; it requires

and can be handled as an easy-to-treat liquid. Conventional coalmore complex handling than a fluid does, environmental

slurry, without additives could be piped but, due to anmeasures must be undertaken to prevent the dispersion of its

approximate 50% water content, exhibited poor long-run stability,

dust, and a lot of space is required to store it. Utilizing it in aand required dehydration before firing. High-concentration CWM

slurry form offers the potential to make the use of coal cleaner,

can now, as a result of studies on the particle size distribution ofcomparable to heavy oil. One type of coal slurry, coal oil mixture

coal and the development of a dispersant and other additives, be(COM), is prepared by adding heavy oil to coal. This is different

kept fluid as well as stable even when less water is added,

than another slurry, coal water mixture (CWM), a mixture of coalallowing it to be directly combusted without being de-watered.

and water. While COM is convenient for burning and while it was

The inclusion of only a small amount of additives stabilizes thetested before CWM, it failed to catch on because of the demandcoal-water slurry in which coal particles of a certain sizefor heavy oil for other uses. CWM, on the other hand, poses no

distribution are uniformly dispersed, constituting a weightproblems relative to spontaneous combustion or dust dispersion

concentration of approximately 70%.

2. Characteristics of high-concentration CWM
The typical characteristics of high-concentration CWM (Chinese

3) Particle size distribution

coal CWM) are shown in Table 1 below.

For higher concentration and stability CWM, the size of thepulverized coal should preferably be distributed over a wide range

Table 1 Characteristics of high-concentration CWM
Coal concentration (wt%)
Higher heating value (kcal/kg)
Lower heating value (kcal/kg)
Apparent consistency (mPa-s)
Specific gravity (-)
Ash content (wt%)
Sulfur content (wt%)
Grains of 200 mesh or less (%)

rather than narrowly distributed. Standard particle sizes used are

68-70
5,000-5,200
4,600-4,800
1,000
1.25
6.0
0.2
80-85

roughly as shown in Table 2.
Table 2 Grain size distribution of high-concentration CWM
Maximum grain size

150-500 m

Average grain size

10-20 mGrains of 74 m or less

80% or more

Fine grains of several micrometers or less

Around 10%

1) Coal type4) Rheological characteristics

In general, high-carbonization, low-inherent moisture (about 5%

CWM’s fluidity has characteristics of a non-Newtonian fluid but

or less in approximate analysis), and low-oxygen content (about

can be characterized as approaching a Bingham fluid. The fluidity

8% or less in ultimate analysis) coal is suitable for high-characteristics also change, depending upon the type of coal,concentration CWM.

concentration, additives, and flow state. The apparent viscosity is2) Additives

roughly 1,000mPa-s (at room temperature and shear speed of

Additives consist of dispersants and stabilizers. A dispersant

100/s).

functions to disperse coal particles into slurry, using electrostatic5) Heating value

repulsion effects or steric repulsion effects; sodium sulfonate fromThe heating value depends upon the type of coal used. An

naphthalene, polystyrene, polymethacrylate, polyolefine, and the likeaverage lower heating value is 4,600-4,800kcal/kg.

are used here. Additives, including the stabilizers CMC and xanthangum, are used to prevent coal particles in the slurry from settling.
3. Manufacturing process for high-concentration CWM
High-concentration CWM can be

Receiving/storage of feed coalproduced by pulverizng coal into

Crushing

a particle size distribution suitablefor CWM, selecting the correct
additives (a dispersant and astabilizer),

andappropriately

blending the coal, water, andLow concentration
wet pulverization
De-watering
Pulverized coal/water/additives mixing

High concentration
wet pulverization

Dry pulverization

Coal pulverization andmixing with water/additives
by a pulverizer
Pulverized coal/water/additives mixing

additives to manufacture a highlyconcentrated, low-viscosity, highlystable, and good-quality CWM. A
diagram of the CWM manufacturing
process is shown in Figure 1.

Enhancement of mixing
CWM storage
CWM shipment

Fig. 1 CWM manufacturing process70

Coal water mixture (CWM)

Part 2 CCT Overview
Multi-purpose Coal Utilization Technologies (Powdering, Fluidization, and Co-utilization Technologies)

4C3. Briquette Production Technology
Technology Overview

1. Background
Global warming, caused by CO2 and other substances, has

substitute fuel for charcoal is necessary. Briquette production

become an international concern in recent years. To protect

technology, a type of clean coal technology, can help prevent

forestry resources, which act as major absorbers of CO2,

flooding and serve as a global warming countermeasure bycontrolling the ever-increasing deforestation, along with theconserving forestry resources through the provision of a stable

increase in the consumption of wood fuels, such as firewood andsupply of briquettes as a substitute for charcoal and firewood.

charcoal, is an urgent issue. Given this, the development of a

2. Carbonized briquettes(1) Process overview(2) Carbonization stage

The coal briquette carbonization production process consists of a

The raw coal (10% or lower surface water content, 5-50mm

carbonization stage and a forming stage. Figure 1 shows theparticle size) is preliminarily dried in a rotary dryer. The gas

basic process flow.

exhausted from the dryer passes through a multi-cyclone to

In the carbonization stage, an internal-heating, low-temperature

remove the dust before venting the gas to the atmosphere. Figure

fluidized-bed carbonization furnace (approximately 450oC)

2 shows a cross-sectional view of the internal-heating, low-

produces smokeless semi-coke containing approximately 20%

temperature fluidized-bed carbonization furnace, the mostvolatile matter. The carbonization furnace has a simple structure,efficient process for carbonizing semi-coke and one which retains

with no perforated plates or agitator, making it easy to operate

approximately 20% of theand maintain.

volatile matter in the semi-

In the forming stage, the smokeless semi-coke and auxiliary raw

coke.

materials, hydrated lime and clay, are thoroughly mixed at a

The preliminarily dried raw

predetermined mixing ratio. After pulverizing, the mixture iscoal is charged to theblended with a caking additive while water is added to adjust the

middlewater content of the mixture. The mixture is kneaded to uniformly

furnace, and is subjected to

distribute the caking additive, and to increase the viscosity in

fluidization

order to make the forming of the briquettes easy. The mixture is

The semi-coke is discharged

then introduced into the molding machine to prepare thefrom the top of the furnace

briquettes. The briquettes are dried and cooled.

together with the carbonization

sectionofthecarbonization.

gas. Thesemi-cokeisseparated

from

the

carbonization gas by the
primary cyclone and thesecondary cyclone.

Raw Coal

After cooled, the semi-cokeFig. 2 Cross-sectional view ofcarbonization furnace

is transferred to a stockyard, and the carbonization gas is
Dryingsupplied to the refractory-lined combustion furnace, where the
CoaliteCrushing

carbonization gas is mixed with air to combust. The generated hot
CycloneCarbonizing

Kneading

gas is injected into the raw coal dryer and to the succeeding
briquette dryer to use as the drying heat source for the

Desulfurizer
Binderpreliminary heating of the raw coal and the drying heat source ofWater

the formed oval briquettes.
(3) Forming stage

Mixing

The semi-coke (Coalite) produced in the carbonization stage isthe raw material for the briquette, containing adequate amounts

Briquetting

Briquetteof volatile matter, little ash and sulfur, and emitting no smoke orodor. The semi-coke, as the primary raw material, is mixed with

Dryinghydrated lime (sulfur fixing agent), clay (to assist forming), and a
Fig. 1 Process flow of briquette production

caking additive.

71

Clean Coal Technologies in JapanTo attain uniform composition and improved formability, theblended raw materials are fully kneaded. The forming of the
mixture is carried out using a roll-molding machine at normal
temperatures and under approximately 1,000 kg/cm (300-500
kg/cm2) of line pressure. Photo 1 shows the forming state.
In the final stage, the formed briquettes are dried in thecontinuous dryer. Since semi-coke is used as a raw material forthe briquettes, they are highly ignitable and can readily ignite in
the furnace if the dryer is not operated at low temperatures. The
dryer was designed with this temperature-sensitive concern inmind.
Photo 1 Formed briquettes

3. Bio-briquettes
Bio-briquettes are a type of solid fuel, prepared by blending coal

which permeates the coal particles, assuring the combustion ofwith 10-25% biomass, such as wood, bagasse (fibrous reside ofvolatile matter at low combustion temperatures. As a result, theprocessed sugar cane stalks), straw, and corn stalks. A

amount of generated dust and soot is significantly reduced.

desulfurizing agent, Ca(OH)2, is also added in an amount

2. Bio-briquettes prepared by blending biomass with coal have acorresponding to the sulfur content of the coal. Owing to the highsignificantly shorter ignition time. In addition, because of the lowpressure briquetting (1-3 t/cm2), the coal particles and the fibrousexpansibility and caking property of bio-briquettes, sufficient air

biomass material in the bio-briquette strongly intertwine andflow is maintained between the briquettes during continuous

adhere to each other. As a result, they do not separate from each

combustion such as in a fireplace. As a result, the bio-briquettes

other during combustion, and the low ignition temperature

have superior combustion-sustaining properties, and do not diebiomass simultaneously combusts with the coal. The combinedout in a fireplace or other heater even when the air supply is

combustion gives favorable ignition and fuel properties, emits

decreased. This makes it easy to adjust the combustion rate.

little dust and soot, and generates sandy combustion ash, leaving

3. Since fibrous biomass is intertwined with the coal particles,

no clinker. Furthermore, since the desulfurizing agent also

there is no fear of the fused ash in the coal adhering and forming

adheres to the coal particles, the agent effectively reacts with theclinker-lumps during combustion. Instead, the ash falls in a sandy

sulfur in the coal to fix about 60-80% of the sulfur into the ash.

form through the grate. Therefore, aeration is maintained toMany coal ranks can be used, including bituminous coal, sub-stabilize the combustion state. Furthermore, since no clinker isbituminous coal, and brown coal. In particular, the bio-briquettes

formed, the ash contains very small amounts of unburned coal.

produced with low grade coal containing large amounts of ash

4. The bio-briquettes are formed under high compressive force.

and having low calorific value combust cleanly, thus the bio-

Because of this, the desulfurizing agent and the coal particles

briquette technology is an effective technology to produce clean

strongly adhere to each other, and they effectively react during

fuel for household heaters and small industrial boilers.

combustion. With the addition of a desulfurizing agent at a ratio of(1) Bio-briquette production process

approximately 1.2-2 of Ca/S, 60-80% of the sulfur in the coal is

Figure 3 shows the basics of the bio-briquette production

fixed in the ash.

process. The raw materials, coal and biomass, are pulverized to asize of approximately 3 mm or smaller, and then dried. The dried
mixture is further blended with a desulfurizing agent, Ca(OH)2.
The mixture is formed by compression molding in a high-pressure
briquetting machine. Powder coal may be utilized without being
Coal

pulverized. A small amount of binder may be added to some coalranks. The

production

processdoes

notinvolve

Biomasshightemperatures, and is centered on a dry, high-pressure briquetting

DryingPulverization

machine. The process has a simple flow, which is safe and which
does not require skilled operating technique. Owing to the high-DryingPulverizingpressure briquetting process, the coal particles and the biomass
Deodorant

strongly intertwine and adhere to each other, thus the process

Caking additive

produces rigid formed coal, which does not separate during

Caking additive may berequired depending on
coal rank.

combustion.
(2) Bio-briquette characteristics

Mixing

1. Bio-briquette combustion decreases the generation of dust andHigh-pressure briquettingsoot to one-fifth to one-tenth that of direct coal combustion. Direct
coal combustion increases the generation of dust and sootbecause the volatile matter released at low temperatures (200-

Bio-briquettes

400oC) does not completely combust. To the contrary, biobriquettes simultaneously combust the low ignition point biomass,

Fig. 3 Basic process flow for bio-briquette production
72Part 2 CCT Overview
Multi-purpose Coal Utilization Technologies (Powdering, Fluidization, and Co-utilization Technologies)

4C4. Coal and Woody Biomass Co-firing Technology
Research and development: New Energy and Industrial Technology Development Organization;
Chugoku Electric Power Co., Inc.; Hitachi, Ltd.; Babcock-Hitachi K.K.
Project type: High-efficiency biomass energy conversion technology development
Period: 2001-2003 (3 years)

Technology overview

1. BackgroundAs part of their global warming countermeasures, industriallyco-firing options. One is to simply pulverize the woody biomass inadvanced countries are implementing policies to promote theexisting mills and combust the pulverized coal-biomass mixture

adoption of power generation using renewable energy. One offuel in a boiler, using the existing burner. This method requires

these is the Renewable Portfolio Standard (RPS) system. The

fewer equipment modifications and therefore costs less. However,"Special Measures Law concerning the Use of New Energy by

mixtures of more than several percent of biomass cause the mill’sElectric Utilities" (RPS Law) was enacted in April 2003, andpower consumption to sharply increase due to the difficulty ofobligates electric utilities to obtain a specified amount of theirgrinding woody biomass with ordinary pulverizers. The otherenergy from new energy power generation sources. The portion

option is to establish a biomass-dedicated mill. Despite the higherof energy derived from alternative sources is expected toequipment costs, this method is advantageous not only because

increase from 3.3GkWh in 2003 to 12.2GkWh in 2010. Included

a higher ratio of biomass can be utilized but also because thein the definition of new energy is biomass fuel.

amount of NOx generated can be reduced.

The co-firing of coal and woody biomass in the power generation

Technology development of the latter option, commissioned by

sector, though already underway in the U.S. and European

the New Energy and Industrial Technology Development

countries, is new to Japan and is facing a variety of technologicalOrganization (NEDO), is underway.

problems. For pulverized coal-fired boilers, there are roughly two

Combustion test/evaluation

Woody biomass
technology investigation
BoilerFlue gas
treatment

Mill
Coal
BurnerWoody biomass

Separation Storage Drying

Crushing

FS for commercialization

Pre-treatment technology
development

Fig. 1 Process flow of coal/woody biomass co-firing system

73

Clean Coal Technologies in Japan

2. Development target

3. Technologies to be developed(1) Co-firing ratio of woody biomass: 5-10%(1) Woody biomass pre-treatment technology (mainly grinding)(2) Clearance of current regulatory environmental restrictions(2) Woody biomass combustion technology (co-firing burner/biomass-(3) Power generation efficiency comparable to that of existing

dedicated burner)coal thermal power plants: A decrease in net thermal efficiency ofless than 0.5% with a woody biomass co-firing ratio of 5% (on acalorific base).
Bag
filterBurnerMill [1]To stacks

Bin

Biomass

Furnace

HopperFeederHopperCycloneFeederHeaterCrusher

BlowerDrier

Mill [2]Fig. 2 Process flow of pilot-scale test facility

4. Development progress and results
This project, was conducted at Chugoku Electric Power Co., Inc.,

NEDO, for the evaluation of the pilot plant’s combustion results,

Hitachi, Ltd., and Babcock Hitachi K.K., and commissioned bywith an eye toward commercialization.

R&D timetable
2001

2002

2003

2004

2005

Coal/woody biomass co-firing technology R&D (commissioned by NEDO)

Demonstration test

Development of component technologies for processes from receiving to storage,
crushing, dry-boiler combustion, and flue gas/ash disposal

Component technology development results-based
deployment toward demonstration tests

1. Woody-biomass technology investigation
2. Pre-treatment technology development

Planning

3. Combustion test and evaluation

Installation work

4. FS for commercialization

Demonstration test

Review of forest biomass utilization by local governments
Utilization planning and system design/verification

Supply system and other improvements/developments

References

1) Kazuhiro Mae: Coal Utilization Technology Information Journal No. 253, pp. 3-5, Feb. 2002.
2) Hiroshi Yuasa: A collection of lectures from Thermal/Nuclear Power Generation Convention, Fukuoka, pp. 102-103, Oct. 2003.

74

Part 2 CCT Overview
Multi-purpose Coal Utilization Technologies (De-ashing and Reforming Technologies)

4D1. Hyper-coal-based High-efficiency Combustion Technology (Hyper-coal)
Research and development: Japan Coal Energy Center; National Institute of Advanced
Industrial Science and Technology; and Kobe Steel, Ltd.
Project type: Development and Survey of Next Generation Technology for Coal Utilization, promoted by New Energy
and Industrial Technology Development Organization (NEDO)
Period: 2002-2007 (6 years)

Technology overview

1. Background and objectives
Because of abundant coal reserves, the expectations of a stablecombined-cycle power generation systems (a combination of gas

supply, and low cost, the demand for coal is expected to increase.

turbines and steam turbines) achieves more efficient power

The emission of CO2 and other substances during thegeneration than existing pulverized coal-fired power generation. If

combustion of coal, however, has a more significant impact on

impurities such as ash and alkali metals can be removed from coal,

the environment than does the use of other fossil fuels.

the clean coal can be used as fuel to be directly combusted in gas

Given this, it is essential to decrease CO2 emissions from coal-turbines.

fired power plants, which account for a large percentage of the

NEDO is promoting the development of combined power generationcoal consumed. To do so, new power generation technology withtechnology, where coal treated by solvent extraction and ion

higher thermal efficiency must be developed and disseminatedexchange processes to remove the ash and alkali metals to obtainworldwide.

clean coal (Hyper-coal), can be directly combusted in gas turbines.

If coal is directly utilized as a gas turbine fuel, the adoption of
2. What is Hyper-coal?
A solvent with a high affinity to coal is applied during the ash

Once the solvent is removed from the solution, the final product,

extraction process. Ash present in the coal is removed from theHyper-coal, has little ash content.

solution though the use of a solid-liquid separation technology.
CharcoalHyper-coalSolvent

Coal

Solvent penetrates coal.

Cohesiveness of coal breaks down,
and soluble portions are dissolved.

Insoluble portions and ash areremoved as sediment.

Residue coalFig. 1 Conceptual drawing of Hyper-coal manufacturing from coal

3. Hyper-coal production facilities(1) Heating-extraction unit

(2) Solid-liquid separation unit

Coal is first treated with a solvent, and then the

Pictured in Photo 2 is a settler with the ability tosolution is treated by a high-temperature

separate coal from the sediment, (design

filtration process to remove residue, thus

temperature: 500oC, design pressure: 5 MPa).

producing Hyper-coal. (Design temperature:

Five vertically arranged valves collect samples

500oC, design pressure: 3MPa) This unit canto determine the sedimenting state of un-

produce various grades of Hyper-coal samples.

dissolved matter under pressurized and heatedconditions.

Photo 1 Heating-extraction unit

75

Photo 2 Solid-liquid separation unit

Clean Coal Technologies in Japan

4. Features of Hyper-coal- Ash content is decreased to 200 ppm or less. The concentrationof alkali metals (Na, K) is decreased to 0.5 ppm or less by ion
exchange.
- Calorific value increased by approximately 10-20% versus thatof original coal.
- Inorganic sulfur is completely removed.
- Heavy metal content is significantly decreased to 1/100 or less.
- Residue coal, which amounts to 30-40% of original quantity ofcoal, can be used as steam coal.
- Low production costs: about $100/ton of Hyper-coal (HPC).
- HPC has excellent ignitability and combustion properties.
- HPC exhibits good thermal plasticity, and is a good carbon
material for direct reduced iron and for smelting nonferrous metals.
- Since HPC is rich in volatile matter and is free from ash, it is an

Photo 3 Test apparatus for continuous manufacturing of Hyper-coalexcellent gasification feedstock, and it is expected to improve theefficiency of gasification.
5. Configuration of Hyper-coal-based high-efficiency power generation system
Overseas mining site
(coal mine)
Roughly de-ashed coal(ash content: 5% or less)Ion exchange vessels
remove alkali metals thatcause high-temperature
corrosion.

Coal is mixed with the solvent,and the mixture is pressurized
and heated to dissolve thecoal’s organic portions into thesolvent. Insoluble ash is treatedby the settler with gravity. It isremoved as residue coal. The
solvent,
containing
thedissolved coal, is sent to the ion
exchange vessels.

The solution is flash-sprayed
into the drying tower toseparate the solvent. The
solvent is recovered for reuse.

The gas-turbine combined-cycle power generation system is a power
generation system that combines a gas turbine with a steam turbine. With a gas
turbine operating at 1350oC, CO2 emissions are reduced by approximately 20%
compared to a pulverized coal-fired power generation system.

Conventional power generation system. Power isgenerated by combusting the residue coal.

6. Concept of Hyper-coal based power generation system

7. Research and development timetable

Post-evaluation

Interim evaluation

76

Part 2 CCT Overview
Multi-purpose Coal Utilization Technologies (De-ashing and Reforming Technologies)

4D2. Low-rank Coal Upgrading Technology (UBC Process)Research and development: Japan Coal Energy Center; Kobe Steel, Ltd.
Project type: Joint research of technologies applicable in coal-producing countries
Period: 2001-2004 (4 years)

Technology overview

1. Background and process overview
Brown and sub-bituminous coal, accounting for about 50% of

upgrading technology (UBC process) has been developed tocoal reserves, are referred to as "low-rank coal." Applications areenable the effective use of such low-rank coal. This process, anlimited due to its low heating value and spontaneous

adaptation of the slurry dewatering technique in the brown coal

combustibility. Unlike bituminous coal, however, much of the low-liquefaction

rank coal has low sulfur/ash content. Therefore, if it could be

preparation/dewatering,

efficiently upgraded and converted into high-grade, high-heating

recovery, and 3) briquetting (Fig. 1).

process,

consists2)

of3

solid-liquidstages:1)

slurryseparation/solvent

coal, it would greatly contribute not only to a stable energy supply
but also to environmental conservation. A low-rank coal

Raw coalAsphalt

Slurry dewatering

Solid-liquid separation
Decanter

Evaporator(140 C/350kPa)
O

Slurry preparation
Solvent recovery

Wastewater

Recycle solvent

Upgraded brown coal (UBC)

Upgraded brown coal briquette

Fig. 1 UBC process for upgrading low-rank coal

During the slurry preparation/dewatering stage, after theof heavy oil functions to prevent the re-adsorption of moisture andpulverized high-moisture low-rank coal has been mixed withaccumulation of the heat of wetting (Fig. 2).

circulating oil (normally light petroleum oil), and then laced withheavy oil (such as asphalt), and heated in a shell and tube-type

Before dewatering

After dewatering

evaporator, moisture is recovered as water vapor. This water
vapor is sent to the shell side of the evaporator, after beingpressurized by a compressor, to use the waste-heat as aheating source, providing substantial energy savings during thedewatering stage. Low-rank coal also contains numerous poresand the moisture within them is removed in the course of

Capillary water

evaporation. During that time, laced heavy oil is effectively

Surface water

adsorbed into the surface of the pores, thus preventing
spontaneous combustion. Moreover, the water-repellant nature

Selective adsorption of asphalt
into pores

Asphalt

Fig. 2 Fundamentals of low-rank coal upgrading77

Clean Coal Technologies in JapanAt the stage of solid-liquid separation/solvent recovery, after mostof the recycled solvent is recovered from the dewatered slurry by adecanter, the recycled solvent remaining in the pores of the
upgraded coal is recovered by a tubular steam dryer.
Since the upgraded coal produced in the UBC process is still in a
powder form, for transportation to non-local customers it is formed
into briquettes. Using a double roll briquetter, the upgraded coalcan easily be briquetted without the use of a binder. Photo 1 showsa picture of upgraded-coal briquettes.

Photo 1 Briquetted UBC

2. Development target
1) Upgrading cost
Assuming that the FOB price of bituminous coal with a heating

4. Future assignments and prospective commercialization

value of 6,500 kcal/kg is $20/ton, that of 4,500 kcal/kg sub-

The Japan Coal Energy Center and the Research andbituminous coal should be around $13/ton in calorific equivalents.

Development Agency of the Ministry of Energy and Mineral

When upgrading this coal to a calorific value of 6,500 kcal/kg, theResources served as the driving force for building a 5 ton/day (ontreatment cost guideline should be set at $7/ton. However, taking

a raw coal basis) UBC process demonstration plant in Cirebon,

into account the advantages of low-rank coal, such as its low ash

Java Barat province, Indonesia. Operation of the demonstration

content, the R&D team has set a development target to keep

plant was completed in 2005 (Photo 2).

upgrading costs equal to or less than $10/ton.

In low-rank coal producing countries, including Indonesia, coal

2) Thermal efficiency in the upgrading process

producers are highly interested in the UBC process and are

The upgrading of low-rank coal needs to provide a higher thermal

hoping for early commercialization.

efficiency than that obtained from the direct firing of the same
low-rank coal when considering the entire process involved, from
UBC production to power generation. Thus, the minimum thermal
efficiency target for the upgrading process has been set to 90%.

3. Development progress and results
The heating value of upgraded coal, though it varies depending
upon the characteristics of the coal, has been improved to around
6,500kcal/kg, and its spontaneous combustion problem has also
been successfully suppressed. It has also been confirmed thatbriquetted upgraded-coal is similar to normal bituminous coalwhen it comes to ease-of-handling and re-crushing.
Furthermore, upgraded coal, when combusted, quite easily burns
itself out to leave almost no un-burned portion even under low-

Photo 2 Low-rank coal
upgrading demonstration plant

NOx combustion conditions, exhibiting excellent characteristics
as a fuel.

Reference

1) Toru Sugita et al., UBC (Upgraded Brown Coal) Process Development, Kobe Steel Engineering Reports, 53, 42, 2003.

78

Part 2 CCT Overview
Environmental Protection Technologies (CO2 Recovery Technologies)

5A1. Hydrogen Production by Reaction Integrated Novel Gasification Process (HyPr-RING)
Research and development: Japan Coal Energy Center; National Institute of Advanced Industrial Science andTechnology; Ishikawajima-Harima Heavy Industries Co., Ltd.; Babcock Hitachi K.K.; Mitsubishi Materials Corporation;
JGC Corporation
Project type: Subsidized by the Ministry of Economy, Trade and Industry
Period: 2000-2008 (9 years-planned)

Technology overview

1. BackgroundIn addition to its position as the world’s most abundant energy

an earnest need to develop technology to use coal cleanly and morereserve, coal is used as an important primary energy source due toefficiently. In response, a process called HyPr-RING that enables theits economic advantages as well. Future consumption is expected tohydrogen necessary for future hydrogen-energy communities to be

increase with economic growth as well as an increasing population.

produced from coal is now under development for commercialization.

Meanwhile, in response to global warming caused by CO2, there is
2. Theory of HyPr-RING process
HyPr-RING is a process in which a CO2-sorbent, CaO, is directly

Gasification gas must be sent through a low-temperature shifter

added into a coal gasifier and the CO2 generated by coaland then exposed to a low-temperature absorbent such as amine

gasification is fixed as CaCO3, together with the produced

for CO2 separation. At that time, the amount of CO2 gas separatedhydrogen. The reaction between CaO and H2O produces the heatis one mole per mole of hydrogen.

necessary for subsequent coal gasification in the gasifier. Within

On the other hand, the HyPr-RING process uses dry CaO to

the gasifier, a series of reactions from equation (1) to equation (4)absorb CO2 in the furnace (650oC, 30 atm). In this case, heat isand the overall reaction of equation (5) take place.

released during CO2 absorption to maintain a high temperature in
the gasifier.
Here, post-CO2 absorption CaCO3 is returned to CaO by calcination(reproduction) and, at that time, 50-80% of the thermal energy
required is converted into CaO for reuse in the gasifier (Fig. 2).
As seen from equation (5), 2-mole hydrogen production from one

This overall reaction is an exothermic reaction with C, H2O, andmole of carbon is another important feature.

CaO as initial reactants. This means that, in theory, there is noneed for external heat. It was also discovered that CO2 fixation
enhances reactions (2) and (3) for H2 generation. Figure 1 shows
the process concept of HyPr-RING. CaCO3 is regenerated bycalcination into CaO for its recycle as a sorbent. Most of the heat
energy required for calcination is carried as the chemical energy of
CaO and made available for coal gasification to produce H2 in thegasifier.
How is this different from conventional gasification?
Conventional gasification secures the heat necessary for
gasification through a partial combustion of coal, with a reaction

Fig. 2 Hydrogen production using HyPr-RING process

taking place in the gasifier expressed by the following equation:
Table 1 CO2 separation energy and temperature level

Heating value of carbon (C CO2)
CO2 absorption energy
CO2/H2 generation ratio
CO2 separation energy
per mole of H2 generated
Temperature level

Fig. 1 Concept of HyPr-RING process
79

HyPr-RING(CaO absorption
process)

Partial combustion(Monoethanolamine
absorption process)393 kJ/mol
178 kJ/mol
0.5 mol/mol

393 kJ/mol
84.5 kJ/mol
1 mol/mol

89 kJ/mol

84.5 kJ/mol

973-1073 K

about 323 K

Clean Coal Technologies in Japan

3. Characteristics of HyPr-RING process
also employed to prevent the eutectic melting of calcium minerals.

Cold gas efficiency

In such cases, unreacted product carbon can be used as a heat

The HyPr-RING process gasifies the easy-to-gasify portion ofosource for CaO reproduction.

coal under low-temperature (600-700 C) conditions into
for CaCO3 calcination.

Coal
1,000 t/dFigure 3 shows an example of a HyPr-RING process

Methane reforminghydrogen and uses the remaining difficult-to-react char as fuelMixingconfiguration with a fluidized-bed gasifier and an internal

Rock hopper

Heat
exchange
Cyclonecombustion-type calcining furnace. For product gas compositionof 95% H2 and 5% CH4, the cold gas efficiency proved to beabout 0.76.

Heat exchange

CaO absorbent

Gasifier

reacts with H2O to produce Ca(OH)2, providing heat-to-coalCalcining

At the gasifier inlet, where the temperature is low, CaO first
Water
vapor

pyrolysis. Then, at a high-CO2 partial pressure region, Ca(OH)2

O2
separation

Coal supply
1,000 t/dHeating value
6,690kcal/kg

absorbs CO2 to produce CaCO3, and releases heat. This heatis used for the gasification of char. To prevent CaO from

Cold gasefficiency
0.76

becoming less active due to high-temperature sintering, amethod of absorbing CO2 in the furnace, by way of Ca(OH)2, is

Steam turbine

employed. Gasification at a temperature as low as possible isFig. 3 Analysis of HyPr-RING process

4. Project overview
Table 2 Targets

Under this project, which commenced in 2000, process
configuration identification and FS through testing withbatch/semi-continuous equipment were paralleled with a variety
of factor tests required. In and after FY2003, it is expected that
50-kg/day (coal base) continuous test equipment will be

Item

Target1. Gasification efficiency
2. Product gas purity
3. CO2 recovery

1. Cold gas efficiency: 75% or greater
2. Sulfur content of product gas: 1ppm or less
3. High-purity CO2 recovery rate: 40% or

fabricated for continuous testing and then, based on the results,

greater of inputed coal carbon to be recovered(per-unit of energy CO2 exhaust to be lessthan that from natural gas)running tests and a FS of a 5 ton/day-scale pilot plant are to be
carried out in and after 2006 to establish a commercialization
process. Table 2 shows development targets of the project andTable 3 shows, the project timetable.
Table 3 Development timetable
Activity

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

(1) Fundamental test(4) 500-kg/day PDU(5) FS
Pilot plant test
(moving to the 2nd phase)

References

1) Shiying Lin, Yoshizo Suzuki & Hiroyuki Hatano, Patent No. 29791-49, 1999.
2) Energy Technology and the Environment, Editors: A. Bisio and S. Boots, John Wiley & Sons, New York, 1995.
80

Final evaluation(3) 50-kg/day test facility

Mid-term evaluation

Mid-term evaluation(2) Acquisition of design data

2010

Part 2 CCT Overview
Environmental Protection Technologies (CO2 Recovery Technologies)

5A2. CO2 Recovery and Sequestration Technology
Technology overview

1. CO2 recovery technology(1) CO2 recovery technology (for natural gas, syngas, and flue gas)

resulting in global warming, which can only be prevented through theCO2 separation/recovery is widely prevalent in the natural gas andmitigation of CO2 emissions. There are, however, many difficulties insyngas fields and has been carried out for decades. The CO2 inrecovering and sequestering CO2 from movable bodies such as

natural gas is not only useless because it decreases the caloric

automobiles and vessels, naturally rendering it easier to recover CO2

value of natural gas, but also because it creates problems at

from stationary sources, like boilers, gas turbines, etc.

LNG/ethane recovery plants by solidifying into dry ice. CO2 is hence(3) Characteristics and superiority of technology to recover CO2 fromremoved to prevent such problems.

exhaust gas

In a plant where natural gas or naphtha is reformed to manufacture

The Kansai Electric Power Co., Inc. and Mitsubishi Heavy

H2, CO2 is separated after being converted from the CO produced

Industries, Ltd. began a joint R&D program in 1990 to recover CO2

with hydrogen as syngas. In an ammonia/urea plant, CO2 isfrom the exhaust gas of power plants and other facilities as aseparated from the gas mixture of H2, N2, and CO2 to produce urea,

global-warming countermeasure. First, they assessed theusing H2/N2-derived synthetic ammonia and separated CO2.

conventional "monoethanolamine" (MEA) liquid absorbent-based

Previously, however, CO2 separation/recovery from flue gas was nottechnology considered at that time a CO2 recovery process thatin such large demand, finding limited applications only in food

could save the largest amount of energy. It is a process developed

processing and dry ice. When CO2 is separated from natural gas orby the former Dow Chemical Co. and later assigned to Fluor

syngas, the separation is relatively easy because of the highDaniel,pressure of the gas. To the contrary, CO2 separation/recovery fromdisadvantageous for use in large plants as a measure against

flue gas is difficult in many technological respects due to the very low

global warming because of such problems as the large amount ofpressure of flue gas as well as the presence of oxygen, SOx, NOx,energy required for CO2 recovery and the great loss in the liquidand soot and dust in the flue gas.

absorbent due to its rapid degradation. Kansai Electric Power and

Inc.

This

MEA-based

technology

was

found

(2) Necessity to recover CO2 from fixed sources

Mitsubishi Heavy Industries started with basic research to explore

Most fossil fuels (oil, natural gas, and coal) in the world are used asa new liquid absorbent, resulting in the successful development offuel for boilers, gas turbines, and internal combustion engines,

a novel energy-saving liquid absorbent less prone to degradation. It

releasing CO2 into the atmosphere as exhaust gas. As a result, it is

has already been put into practical use for the manufacture of urea

alleged that the atmospheric concentration of CO2 has increased,in Malaysia.

2. CO2 sequestration technology
Geological sequestration and ocean sequestration are being

displacing the water. This is already underway in Norway. For

widely studied and a commercial project of the former has

Japan, Norway-like CO2 sequestration into aquifers distributed

already begun. Geological CO2 sequestration is being carriedover continental shelves are considered the most realistic.

out, using the Enhanced Oil Recovery (EOR) method or the coal

Other than into aquifers, CO2 can also be sequestered into

seam sequestration-accompanied Coal Bed Methane Recovery

closed oil/gas fields where production has already been

method. Aquifer sequestration and sequestration into closed

terminated. Closed oil/gas fields once were active oil/gas fields

oil/gas fields are options as well, if the only objective is CO2

because their geological structures did not permit oil/gas leaks.

sequestration. Figure 1 shows a conceptual view of CO2

Therefore, such closed oil/gas fields are considered secure CO2

recovery-EOR combination.

sequestration sites.

CO2-EOR commercialization started in the 1970’s mainly in the
United States, enhancing oil production by approximately
200,000 barrels/day. Outside the United States, Canada, Turkey,and Hungary also utilize the CO2 recovery-EOR combination.
Underground aquifers are widely distributed on the earth wherever
sedimentary layers are located. Even in Japan, where aquifers are
scarce and small in structure because of Japan’s volcanic andearthquake history, surveys are underway for possible CO2
sequestration sites. If a geological underground layer has cavities,
CO2 can be sequestered in these cavities, which indigenously
contain water (mainly salt water), by pumping in CO2, thereby

Photo 1 Conceptual view:
CO2 recovery from power plant flue gas for EOR

Reference

Masaki Iijima et al., "CO2 Recovery/Effective Utilization/Fixation and Commercialization," MHI Technical Journal, 39 (5), 286, 2002.
81

Clean Coal Technologies in Japan

5A3. CO2 Conversion Technology
Technology overview

1. Urea production
At present, urea is produced from ammonia and carbon dioxide,
which is generated from inexpensive natural gas (off-gas) during
the manufacture of ammonia. When urea is synthesized withnatural gas as a raw material, however, the available CO2 may beinsufficient in view of the balance between ammonia and off-gas
CO2. In such cases, CO2 is recovered from the exhaust gas ofthe steam reformer, which produces hydrogen and CO fromnatural gas, to supply it for urea synthesis to adjust the ammoniaCO2 balance, thereby enabling urea to be produced in large
quantities. A plant Mitsubishi Heavy Industries, Ltd. delivered to
Malaysia PETRONAS Fertilizer Sdn. Bhd. (Photo 1) matches thispurpose.
Photo 1 Urea plant

2. Methanol production
Methanol is now also manufactured mainly with natural gas asfrom steam reformer flue gas to optimize the H2:CO ratio for

the feedstock. If H2 and CO are synthesized by steam-reforming

methanol synthesis, thereby enhancing methanol production.

the natural gas, then the H2:CO ratio is 3:1. On the other hand,for methanol synthesis, the best H2:CO ratio is 2:1, and theoutput of methanol can be maximized through the recovery of

CO2

CO2 from steam reformer flue gas, allowing the addition of a

CO2 recovery

Exhaust gas
Natural gas
SyngasSteam reformer
compressor
Steammeaningful amount of CO2 into the process. At present, activeplanning for CO2 addition is underway to improve the production
capacity of Saudi Arabian methanol plants.

Methanol
synthesis

Methanol

Fuel

Figure 1 shows a system where, in the process to produce

Fig. 1 CO2 recovery from flue gas for enhanced methanol production

methanol with natural gas as the feedstock, CO2 is recovered

3. DME (dimethyl ether) production
DME is currently synthesized from methanol. The process issimilar to that used for the above-mentioned methanol

CO2production.

CO2 recovery

Exhaust gas
Natural gas
SyngasSteam reformer
compressor
Steam

Methanol
synthesis

DME
DME
synthesis

FuelFig. 2 CO2 recovery from flue gas-integrated DME production system

4. GTL production
GTL, or Gas-to-Liquid, generally refers to a process to synthesize
kerosene and light oil by the Fischer-Tropsch Process (FT
CO2

Process). For this GTL synthesis, as in the case of methanol, it is

CO2 recovery

Exhaust gas
Natural gas
SyngasSteam reformer
compressor
Steam

necessary to adjust the H2:CO ratio to 2:1 and recover the same
volume of CO2 from the steam reformer flue gas for use in theprocess, also as in methanol production, to enable the H2:COFT
Synthesis

Liquid fuelFuel

ratio to be adjusted.

Fig. 3 CO2 recovery from flue gas-integrated liquid fuel production system

The system recovers and recycles CO2, which does notcontribute to the reaction from the FT synthesis process, to thestage prior to steam reforming.

Reference

Masaki Iijima et al., "CO2 Recovery/Effective Utilization/Fixation and Commercialization," MHI Technical Journal, 39 (5), 286, 2002.
82

Part 2 CCT Overview
Environmental Protection Technologies (CO2 Recovery Technologies)

5A4. Oxy-fuel Combustion (Oxygen-firing of Conventional PCF System)
Research and development: Japan Coal Energy Center; J-POWER; Ishikawajima-Harima Heavy Industries, Co., Ltd.;
Taiyo Nippon Sanso Corporation (Nippon Sanso Corp.); and Institute of Research and Innovation
Project type: Coal Production and Utilization Technology Promotion Grant
Period: 1992-2000 (8 years), 2004-2005 (2 years)

Technology overview

1. Background and the oxy-fuel combustion system
The Kyoto Protocol entered into force in February 2005, and now

and to easily recover CO2.(1) When this technology is applied tomany countries are working actively toward the second

power plants for the purpose of controlling the flame temperature,commitment period starting in 2013. From a global viewpoint,

flue gas (mostly CO2) is recirculated and mixed with O2. With thishowever, thermal power plants are releasing CO2 in large

technology, it has been confirmed that the process characteristics

quantities, which indicates the necessity for a power generation

help reduce NOx emissions. Expectations for this system are highsystem with CO2 recovery and storage capabilities. Among all the

because it represents a direct CO2 recovery method that is better

fossil fuels used at thermal power plants, coal produces thethan other CO2 recovery systems in terms of economical efficiency

greatest amount of CO2 per calorific unit value.

and technological feasibility.

In the process of recovering CO2 through oxy-fuel combustion as

In the future, it will be increasingly necessary to establish a coal-shown in Figure 1, O2 is separated from combustion air and used

fired power plant with CCS (Carbon Dioxide Capture and Storage).

for burning coal. In this process, it is theoretically possible toIn this respect, it will be important to integrate the power generating

improve the CO2 concentration in the emissions to 90% or more,unit and the CO2 recovery and storage capabilities.

N2

Non-condensable gas

Coal
BoilerAir

Flue gas
treatment
CO2 storage

O2
Compression/cooling
Oxygenproduction unit

H 2O
Flue gas recirculation

Fig. 1 Concept of oxy-fuel combustion with CCS

2. Development results
An application study on an existing 1000MWe coal-fired power

oxygen production account for more than half of the total cost,plant was carried out to examine the system structure and theand thus it is hoped that innovative oxygen production technology

boiler furnace, as well as the operating and economic efficiency.

will be developed.

Table 1 and Figure 2 show the specifications of the existing 1,000
MWe power plant when the oxy-fuel combustion system was
Table 1 Specifications of a plant with oxy-fuel combustion system

introduced. In applying oxy-fuel combustion, motive power isSpecifications

Unit

Air combustion

Oxy-fuel combustionnecessary for oxygen production and CO2 recovery. The station

Rated output

MWe

1050

1050

service power occupies up to 30% of the total electricity

Net efficiency

%

40

30

Station service power

generated, and the net efficiency is 30%. The amount of CO2

%

5

30

Availability

%

80

80

recovered is about 800 t/hr (or about 5 million tons per year.)

Coal consumption

t/h

330

330

(Australian coal)

According to our calculation, the cost for CO2 separation andOxygen supply

km3N/hCO2 recovery rate%

480 (in Air)_

430

recovery is approximately 3,000 yen per ton-CO2. In this process,the initial cost and the operational and maintenance costs forCO2 recovery

t/hr

_

802

83

95

Clean Coal Technologies in Japan

3. Demonstration project in Australia

CO2 recovery-type oxygen pulverized coal combustion power plant

On the basis of the study results described above, demonstrative
studies are now underway for applying oxy-fuel combustion to an
existing plant.(4) These studies include an Australia-Japan joint
project in which an oxy-fuel combustion demonstration plant will becompleted by the end of 2008. This project aims to recover andCO2 underground sequestration

Boilerstore CO2 from an existing power plant. The outline of the project is

Oxygen production facility

as follows:

CO2 tank

The project is being implemented at a power generation plant in the
Callide-A power plant’s No. 4 unit owned by CS Energy on the east
coast of Australia. This unit was selected because it has adequate

CO2 ocean sequestration

capacity as a demonstration plant. Additionally, it is currently out ofFig. 2 Image of CO2 recovery-type power plant applying oxygen combust

service and thus is available for modifications.
The storage site is planned to be located in a depleted gas field,

feasibility study from FY2004 to FY2005. Based on its results,

about 250 km to the west of the power plant. This site was chosendetailed studies began in 2006, aiming at completing the plant by

because it is not far away from the power plant, the estimated CO2

the end of 2008. Demonstrative operation of the oxy-fuelstorage capacity is sufficient, and the reservoir characteristics suchcombustion system will be carried out for five years afteras permeability and porosity are adequate.

completion. Storage of captured CO2 will start in FY2011, and thus

The entire project schedule is shown in Table 2. For thisdemonstration and monitoring of CO2 storage will be carried out for

demonstration project, Australia and Japan jointly conducted athree years.

Table 4 Project schedule
2004

2005

Feasibility sudy

Boiler modification & demonstrationof CO2 recovery

Demonstration of CO2 storage

2006

2007

2008

2009

2010

2011

2012

2013

2014

2015

FS
Design,construction,commissioning

Demonstrative operation

Test
Testdrilling,
drill, design,design,construction,
construction,commissioning
commissioning

CO2 storage & monitoring

Summary

4. Issues and feasibility of practical application
As described above, the demonstration of a power plant using oxy-demonstration and further studies:

fuel combustion is now about to start. Hopefully by the year 2010, it(1) Stability and safety in the operation of a power plant using oxy-

will be demonstrated that the system is reliable and economically

fuel combustion

efficient for CO2 recovery. It is necessary first and foremost to(2) Stable operation of a CO2 recovery system

ensure the steady implementation of the Australia-Japan(3) Efforts for reducing costs and enhancing efficiency

demonstration project, so that it will be the first step toward(4) Total system optimization for power generation and CO2commercialization. The following topics will be the subjects of therecovery/transportation/storage

References

1) K. Kimura et al., JSME-ASME Int. Conf. On Power Eng.-93, Tokyo, Sept. 1993.
2) NEDO, "Report on the Clean Coal Technology Promotion Project 2004: Study on the Application of Oxygen Combustion Technology
to an Existent Pulverized Coal-Fired Power Plant".
3) NEDO, "Report on the Clean Coal Technology Promotion Project 2005: Study on the Application of Oxygen Combustion Technology
to an Existent Pulverized Coal-Fired Power Plant".
4) C. Spero, Proc. Clean Coal Day in Japan 2004, Advanced Clean Coal Tech. Int. Symp. Tokyo, Sept. 2004.
84

Part 2 CCT Overview
Environmental Protection Technologies (Flue Gas Treatment and Gas Cleaning Technologies)

5B1. SOx Reduction Technology
Technology overview

1. BackgroundSulfur oxides (SOx, mainly SO2) are regulated by a "K-value"and lower costs have been ongoing. At present, most pulverized

control, which uses exhaust heights and regional coefficients tocoal-fired thermal power plants are equipped with wet limestone

limit SOx emissions. "Total amount control" is a term used inand gypsum-based desulfurization systems. Furthermore, a wet

Japan to define the total emissions from the whole of a region.

desulfurization process requiring no wastewater treatment is now

To comply with these regulations, flue gas desulfurizers were

under development.

commercialized in 1973. Efforts to improve their performance

2. Technology(1) Wet limestone-gypsum process

The overall reaction is as follows:

Research and development: Mitsubishi Heavy Industries, Ltd.;
Babcock Hitachi K.K.; Ishikawajima-Harima Heavy Industries Co., Ltd.;
Chiyoda Corporation; Kawasaki Heavy Industries, Ltd.; others

CaSO3-0.5H2O+0.5O2+1.5H2O

CaCO3+SO2+0.5H2O

CaSO3-0.5H2O+CO2
CaSO4-2H2O

There are two types of absorption towers, as shown in Figure 1: a

Overview

CaSO3-0.5H2O separate tower oxidation system and a

There are two limestone-gypsum processes; a soot-separation

comprehensive single tower oxidation system. At present, single

process, in which a dust (cooling) tower is installed upstream for

tower oxidation systems are less expensive to install and operate

dust collection and HCI/HF removal and cooling, and a soot-and their use is increasing annually. There are several methods tomixed process without such a dust (cooling) tower. The soot-have recycled absorption liquid come into contact with SO2 in theseparation process is used when high-purity gypsum containing

absorption tower section; the "spray method," which sprays theno soot or dust is desired. At present, however, more and moreabsorption liquid, the "grid method," which spreads absorption

systems employing the soot-mixed process, which is lessliquid on the surface of a grid-like pad, the "jet-bubbling method,"

expensive to install, are being installed since high-performance

which blows exhaust gas into the absorption liquid, and thedust collection devices, such as an advanced low-temperature"water-column method," in which absorption liquid flows in theelectrostatic precipitator, which lowers soot/dust concentrations,absorption tower.

have been developed.

For developing countries, a simple desulfurizer installable in the

In the absorption tower, on the other hand, a water-mixed

flue gas duct or at the lower part of a smoke stack has also beenlimestone slurry is reacted with SO2 within the exhaust gas forcommercialized.

the recovery of sulfur contents as gypsum (CaSO4-2H2O).

Oxidation tower-separated typeIn-absorption tower oxidation type

Absorption tower
Sulfuricacid

Absorption tower
Oxidation
tower

Basic flow
Gypsum
Gas

Gas

Air
Limestone

Limestone

Absorption tankGypsumAbsorption tower tank

Air

Fig. 1 Limestone-gypsum process-based desulfurizers

85

Clean Coal Technologies in Japan(2) Coal ash-based dry desulfurization process

approximately 20% and a dust collection efficiency of 96% orResearch and development: Hokkaido Electric Power Co., Inc.;
Hitachi, Ltd.; Babcock Hitachi K.K.
Project type: Subsidized development of oil-alternative
energy-related technology for commercialization
Development period: 1986-1989

more. By 2003, the technology had been installed at Hokkaido
Electric Power’s Tomatoh-Atsuma Thermal power plant No. 1
unit (350MW), where the equipment is being used to treat one-Spent
desulfurization agent

Boiler Exhaust gas

Water
Kneader

Drier
Hot air

is a process to produce a new absorbent from limestone,

Conveyorcalcium hydroxide (Ca(OH)2) and spent absorbent. By using the

Mixer

ExtruderConveyor

newly produced absorbent, SOx is removed from the flue gas.
Figure 2 shows an outline of this process, which also includes a

Scalestage to manufacture the absorption agent. The desulfurization

Clean
gas
Desulfurization
fan

Scale

Steam

Primary absorption
agent

technologies developed to make effective use of coal ash. This

Pre-absorption agent

The coal ash-based dry desulfurization process was one of theDesulfurization
silo

Overview

Slack lime

Coal ashhalf of the flue gas.

ScreenSteam generator

reaction allows Ca(OH)2 to remove SO2. Temperatures aremaintained between 100-200oC, where an SOx removal

Spent desulfurization agent
Breaker

efficiency of 90% or greater can be attained. The process can

Fig. 2 Coal ash-based dry desulfurization process

also remove dust and NOx, with a NOx removal efficiency of(3) Spray dryer processtake place simultaneously, giving a particle mixture of gypsum

Research and development: The Electric Power Development
Company; Mitsubishi Heavy Industries, Ltd.;
Hokkaido Electric Power Co., Inc.
Project type: Voluntary under the Green Aid Plan

particles are recovered at a down-stream precipitator. Since thisOverview

waste. J-POWER, as part of the "Green Aid Plan," installed a spray

The spray dryer process is a so-called "semi-dry process," where

dryer desulfurizer with an exhaust gas treatment capacity ofwater is added to burned lime (CaO) to make a slack lime

300Km3N/h (one-half of total exhaust) at the Huangdao power(CaSO4-H2O) and calcium sulfite (CaSO3-0.5H2O). These
process is not adequate for good-quality gypsum and, moreover,ash remains in the mix, desulfurized particles are disposed of as(Ca(OH)2) slurry, which is sprayed into a spray dryer, causing theplant No. 4 unit (210MW) in Qingdao, China. It is currently in

SO2 in the flue gas to react with Ca(OH)2, and to be removed.

operation and attained a 70% desulfurization rate in verification

Within the dryer, the desulfurization reaction and limestone drying

tests (Oct. 1994 through Oct. 1997).

(4) Furnace desulfurization process

remove SO2 at a furnace temperature of 760-860oC:

Research and development: Hokkaido Electric Power Co., Inc.;
Kyushu Electric Power Co., Inc.; J-POWER;
Chugoku Electric Power Co., Inc.; Mitsubishi Heavy Industries, Ltd.;
Ishikawajima-Harima Heavy Industries Co., Ltd.;
Kawasaki Heavy Industries, Ltd.
Project type: Voluntary

CaCO3

CaO+CO2 CaO+SO2

CaSO3

At present, this process is employed at J-POWER’s Takehara
thermal power plant No. 2 unit normal-pressure fluidized-bed
boilers as well as the pressurized fluidized-bed boilers of
Hokkaido Electric Power’s Tomatoh-Atsuma thermal power
plant, Kyushu Electric Power’s New Kanda thermal power plant,
and Chugoku Electric Power’s Osaki thermal power plant. In

Overview

pressurized

The furnace desulfurization process is used for fluidized-bed

breakdown into CaO due to the high partial pressure of CO2,

fluidized-bed

boilers,

limestone

doesboilers. Limestone to be used for desulfurization is mixed andbut SO2 is removed in accordance with the following reaction:

combusted with the coal, causing the following reaction to

CaCO3+SO2

CaSO3+CO2

References

1) "Introductory Course: Environmental Preservation Technology/Equipment for Thermal Power Plants IV Desulfurization Equipment,"
Thermal/Electronic Power Generation Vol. 41 No. 7, 911, 1990.
2) Kudo et al., "Coal Ash-Based Dry Desulfurizer Development," Thermal/Electronic Power Generation, Vol. 41, No. 7, 911, 1990.
3) "Coal Ash-Based Dry Flue Gas Desulfurizer" pamphlet, Hokkaido Electric Power.
4) General View of Thermal Power Generation, Institute of Electric Engineers, 2002.

86

not

Part 2 CCT Overview
Environmental Protection Technologies (Flue Gas Treatment and Gas Cleaning Technologies)

5B2. NOx Reduction Technology
Technology overview

1. Background
Nitrogen oxide emissions are regulated, with acceptablegas denitration equipment was commercialized in 1977, andconcentration levels set according to the type of fuel and the size

ongoing efforts have been made to improve the durability ofof the boiler. However, with the recent stiffening of regulations,

DeNOx catalysts as well as to reduce costs. The Selective

some regions are subject to a "total amount control," which

Catalytic Reduction (SCR) process is used to decompose

provides for a region-wide overall emissions level as is the casenitrogen oxides, mainly through the use of ammonia.

with sulfur oxide emissions. To comply with these regulations, flue

2. Technology(1) Selective catalytic reduction process

Research and development: Mitsubishi Heavy Industries, Ltd.;
Ishikawajima-Harima Heavy Industries Co., Ltd.; Babcock
Hitachi K.K.

process is also designed to limit NH3 leaks from the reactor to

Overview

clogs the piping when separated out by an air pre-heater.

In this process, ammonia (NH3) is blown into exhaust gas,

The NOx removal efficiency is around 80-90% for pulverized

allowing the ammonia (NH3) to selectively react with nitrogencoal-fired thermal power plants. On the other hand, measures to5ppm or less. If a significant quantity should leak, it will reactwith the SO3 in the exhaust gas, producing NH4HSO4, which

oxides NOx (NO, NO2), and decompose them into water (H2O)

equally disperse and mix the NH3 with the exhaust gas as welland Nitrogen (N2). In the DeNOx reactor, since soot and dust are

as to create greater uniformity of the exhaust gas flows to copepresent in the exhaust gas, a grid- or plate-like catalyst is mainlywith growing boiler sizes have been developed. These include

used, as shown in Figure 1. The catalysts, as shown in Photo 1

placing a current plate, called a "guide vane" at the gas inlet, or

and Photo 2, are installed in the reactor to react with the NH3

dividing the gas inlet into grids, each to be equipped with anblown into the catalyst layer from its inlet, allowing NOx (NO,NH3 injection nozzle.

NO2) to breakdown into water vapor (H2O) and nitrogen (N2). The
catalyst is mainly composed of TiO2, to which vanadium (V),

Smokestacktungsten (W), and the like are added as active ingredients.
4NO + 4NH3 + O2

4N2 + 6H2O

The temperature at which the catalyst attains optimal

Catalyst
layer

performance is 350oC. At a temperature lower than this, SO3 inthe exhaust gas reacts with NH3, producing ammonium hydrogensulfate (NH4HSO4) that covers the surface of the catalyst,
thereby reducing the ability to remove NOx. At a temperature
higher than 350oC, the NH4HSO4 decomposes, improving the

Exhaustgas

removal of NOx regardless of the SO3 concentration. At a

Reactorotemperature above 400 C, NH3 is oxidized and its volume
decreases, thereby reducing its ability to remove NOx. The

Fig. 1 Selective contact reduction method denitration process

Photo 1 Grid-like catalyst

Photo 2 Plate-like catalyst

87

Clean Coal Technologies in Japan(2) Selective non-catalytic reduction (SNCR) process

Research and development: Chubu Electric Power Co., Inc.; Mitsubishi Heavy Industries, Ltd.
Project type: Voluntary
Overview
SNCR is a process to, as shown in Figure 2, blow NH3 into theboiler section where the exhaust gas temperature is 850-950oC
and to breakdown NOx into N2 and H2O without the use of a

Injection
nozzlecatalyst. Despite the advantages of not requiring a catalyst andBoiler water for nozzle-coolingits lower installation costs, the NOx removal efficiency is as low
as 40% at an NH3/NOx molar ratio of 1.5. Because of this, it isused in regions or equipment where there is no need for a highNOx removal efficiency. More NH3 is also leaked than with theselective contact reduction method, requiring measures to copewith NH4HSO4 precipitation in the event of high SO3

AH

Ammonia

concentrations in the exhaust gas.

SAH

Mixer

This technology is mainly used at small commercial boilers and

Air for dilution

refuse incinerators. With respect to thermal power plant

FDF

Booster fan

applications, this technology has only been installed at Chubu
Electric Power’s Chita thermal power plant No. 2 unit (375kw), in

Fig. 2 Selective non-catalytic denitration NOx removal process

1977.

(3) Radical injection method

Research and development: Japan Coal Energy Center
Project type: Subsidized coal production/utilization technology promotion
Development period: 1999-2002
Overview
In the radical injection method, as shown in Figure 3, argon
plasma is injected into NH3, generating NH2 plasma and otherplasmas, which are then blown into the boiler to decompose NOx
into N2 and H2O. The target for this technology is to attain an
NOx concentration of 10ppm or less.
At present, basic research is underway at the Japan Coal Energy
Center, with commercialization expected around 2010.

Fig. 3 Overview of radical injection method

References

1) Masahiro Ozawa et al., "Latest Flue Gas Denitrator Technology," Ishikawajima-Harima Technical Journal, Vol. 39, No. 6, 1999.
2) Tadamasa Sengoku et al., "Selective Non-Catalytic Denitration Method for Boilers," Thermal/Nuclear Power Generation,
Vol. 29, No. 5, 1978.
3) Coal Utilization Next-Generation Technology Development Survey; Environment-friendly coal combustion technology field(advanced flue gas treatment technology)/NEDO results report, March 2002.
4) Masayuki Hirano, "New Flue Gas Denitrator Technologies for Large Boilers/Gas Turbines," Thermal/Electronic Power Generation,
Vol. 50, No. 8, 1999.

88

Part 2 CCT Overview
Environmental Protection Technologies (Flue Gas Treatment and Gas Cleaning Technologies)

5B3. Simultaneous De-SOx and De-NOx Technology
Technology overview

1. Background
The technology behind the wet desulfurization process has also

expensive DeNOx catalysts but also measures to prevent

matured but requires a significant amount of service water as wellammonia leaks. Development efforts are, therefore, underway for

as advanced wastewater treatment measures. Meanwhile, an

a dry combined desulfurization DeNOx method to remove NOx

already commercialized ammonia-based selective catalytic

and SOx simultaneously without requiring any service water,

reduction (SCR) process requires not only long-term control ofwastewater treatment, or a DeNOx catalyst.

2. Technology(1) Active carbon adsorption method

Research and development: J-POWER; Sumitomo Heavy Industries, Ltd.; Mitsui Mining Co., Ltd.
Project type: Voluntary support project for coal utilization promotion
Overview
The active carbon adsorption method causes a reaction between

technology, verified after being up-scaled to a capacity of

SO2 in exhaust gas and injected NH3 on active carbon at 120-

150Km3N/h, was introduced in 1995 to the DeNOx unit of the No.

o

150 C, thereby converting SO2 into ammonium hydrogen sulfate

2 unit of the Takehara coal thermal power plant’s normal-(NH 4HSO 4)

forpressure fluidized-bed boiler (350MW), and is currently inadsorption/removal while decomposing NOx into nitrogen andoperation. This technology was also installed as a desulfurizer inwater as does the SCR process. Figure 1 shows the process. The

2002 at J-POWER’s Isogo thermal power plant’s No. 1 new unit

moving-bed adsorption tower (desulfurization tower) removes(600MW) (Photo 1). Although this technology is currently in

SO2 in the first-stage and, in the second stage (denitration

operation, there are no cases of it being used as a combined

tower), NOx is decomposed. This method first removes SOx anddesulfurization-denitration system.

andammoniumsulfate((NH 4) 2SO 4)

then NOx since, as shown in the figure, the presence of highconcentration SO2 tends to decrease the effectiveness of NOx

Active carbon

removal.

Exhaustgas

regenerated. SO2 can be adsorbed and removed in the form of
sulfuric acid (H2SO4) even if NH3 is not injected in thedesulfurization tower. However, since the following reaction with

Hot
air

Desorption tower

decomposing it into NH3 and SO2, while the active carbon is

Denitration towerhigher in the desorption tower to desorb NH4HSO4 after

Desulfurization tower

Active carbon that has absorbed NH4HSO4 is heated to 350oC or

carbon occurs during desorption, consuming active carbon, NH3
is added at the time of desulfurization to prevent such active
Fig. 1 Active carbon method desulfurization processcarbon consumption.
H2SO4

SO3+H2O

SO3+0.5C

SO2+CO2

Coal is used to reduce desorbed SO2 into elemental sulfur at
900oC for recovery. There is another method that oxidizes SO2
into SO3 to recover it as sulfuric acid.
During the development of this technology, carried out at JPOWER’s Matsushima thermal power plant, first, an activecarbon desulfurization method (with an adsorption tower) that cantreat 300Km3N/h (90MW-equivalent) of gas was subjected toverification tests (1983-1986), obtaining removal efficiency of
98% for SOx and 30% for NOx. To improve the DeNOx removal
efficiency, a combined desulfurization DeNOx pilot plant that cantreat 3,000m3N/h of gas with two towers was tested (1984-1986).
SOx was almost completely removed by the desulfurization tower

Photo 1 Active carbon method desulfurizerin the first stage, while 80% of NOx was removed. This

89

Hot
air

Desorbed gas

Clean Coal Technologies in Japan(2) Electron beam process

Research and development: Ebara Corporation; Chubu Electric Power Co., Inc.; Japan Atomic Energy Research Institute; others
Project type: Voluntary
Overview
The electron beam process, as shown in Figure 2, involves using

For this process, technology development was undertaken by

an electron beam to irradiate SOx/NOx in exhaust gas andEbara Corporation and U.S. partners, including DOE, which madeinjected NH3 to cause a reaction for their recovery as ammonium

joint contributions from 1981-1987. In Japan, based on thesulfate ((NH4)2SO4) or ammonium nitrate (NH4NO3) in thedevelopment results, a pilot plant that can treat 12,000m3N/h ofdownstream precipitator. Byproducts: ammonium sulfate andgas was built at Chubu Electric Power’s Shin-Nagoya power plant,

ammonium nitrate, which are used as fertilizers. Removal

where the technology was verified from 1991-1994.

efficiencies of 98% or more for SOx and 80% for NOx, at an

Regarding this technology, a plant that can treato300Km3N/h

NH3/NO molar ratio of 1, is obtained at 70-120 C. The NOx(90MW) of gas (Photo 2) was built at Chengdu Heat-Electricity

removal efficiency also characteristically increases with higher

Factory, a co-generation power plant in Sichuan Province, China.

SO2 concentrations, though SOx removal efficiency does not

It is currently being operated for demonstration and is obtaining aaffect the concentration of SO2 at the inlet.

NOx removal efficiency of 80%.

Existing
boilerAir
Dry electrostatic
preheater
precipitator

SmokestackAir

Cooling waterElectron beam generator
Dry electrostatic
precipitator

ReactorCooling
tower

Granulator

Ammonia equipment

Nitrogen fertilizer(ammonium sulfate/ammonium nitrate)

Fig. 2 Process flow for electron beam desulfurization process

Photo 2 Electron beam desulfurizer

References

1) Hanada et al., "Dry Desulfurization-Denitration-Technology Dry Active Carbon-Method Sulfur Recovery Formula at Coal Thermal Power Plant"
Thermal/Electronic Power Generation, Vol. 40, No. 3, 1989.
2) "Renewing Isogo Thermal Power Plant" pamphlet, J-POWER.
3) Aoki, "Electronic Beam Flue Gas Treatment Technology," Fuel Association Journal, Vol. 69, No. 3, 1990.
4) S. Hirono et al., "Ebara Electro-Beam Simultaneous SOx/NOx Removal," proc 25th Int Tech Conf Util Sys, 2000.

90

Part 2 CCT Overview
Environmental Protection Technologies (Flue Gas Treatment and Gas Cleaning Technologies)

5B4. Particulate Treatment Technology and Trace Element Removal Technology
Technology overview

1. Background
Like NOx, emissions of particulate matter are regulated, withfollowed suit. To improve power generation efficiency, theacceptable concentration levels set according to the type of fueldevelopment of pressurized-bed combustion and coal gasificationand size of boiler. At present, however, some regions are subject

combined-cycle

to a "total amount control," which provides for a region-wide

ceramic/metal precision-removal filters is underway.

overall emissions level as is the case with sulfur and nitrogen

On the other hand, trace element control is now being intensified,oxides. To comply with the regulations, the world’s firstsuch as through the addition of boron (B) and selenium (Se) toelectrostatic precipitator was employed in a Yokosuka thermal

the regulated wastewater materials, and through the application

power plant in 1966 and many other thermal power plants haveof U.S. regulations for mercury (Hg).

technologies

that

use

cyclones

2. Technology(1) Electrostatic precipitators

Research and development:
Mitsubishi Heavy Industries, Ltd.; Hitachi, Ltd.; Sumitomo Heavy Industries, Ltd.; others
Overview
Electrostatic precipitators remove particulate matter in exhaust
High-voltage DC

gas in accordance with the theory that dust charged by anegative corona at a discharge electrode adheres to a positive

Power supply

dust-collecting electrode.
The particulate matter that adheres to the electrode is removed
and falls when the cathode is tapped with a hammering device.
Discharge electrodeThe effectiveness of the dust removal depends upon theelectrical resistance of the particulate matter, and is most

Collected
particulatemattereffective in an electrical resistivity range of particles 104-1011 cm insize. Pulverized coal, where the thermal electrical resistance ofDust collecting
electrodemany particles is high, requires various countermeasures betaken against such particles.
One such measure involves adjusting the temperature conditions
for dust collection; electrical resistance changes are shown in

Flue gas(from boiler)

Figure 2. Those successfully developed and commercialized
based

on

such

characteristics

areahigh-temperature
Fig. 1 Theory behind electrostatic precipitatoroelectrostatic precipitator operated at 350 C, a higher temperature
than

that

of

conventional

low-temperatureelectrostatic
Low-alkali/
high-sulfur coalresistance, and an advanced low-temperature electrostatic
precipitator, with its electrical resistance lowered by operating it

Low-alkali/
low-sulfur coalat a dew point or lower temperature of 90-100oC. Other thanelectrode method, which brushes off particulate matter by moving
the electrode to prevent back corona due to dust accumulation at
the electrode, and a semi-wet electrostatic precipitator where aliquid membrane is applied to wash away dust. Other methods
are commercialized electric discharge technologies, including anintermittent charge system to supply a pulsed voltage of several
milliseconds, and a pulse charging system for several tens of
microseconds.
At present, leading pulverized coal-fired plants built in and after
1990 employ very low-temperature electrostatic dust collection

Advanced low-temperature ESPConventional low-temperature ESP

Electrical resistivity ( -cm)

these, successful commercialized technology includes a moving

High-temperature ESP

precipitators (130-150oC), in order to lower the electrical

High-alkali/
high-sulfur coal
High-alkali/
low-sulfur coalprocesses that can treat particulate matter with various
properties and shapes.

Temperature (OC)Fig. 2 Temperature effects on electrical resistance of coal ash
91

andClean Coal Technologies in Japan(2) High-temperature dust collection method

Research and development: Mitsubishi Heavy Industries, Ltd.; Hitachi, Ltd.; Kawasaki Heavy Industries Co., Ltd.; others
Overview
The

under

pilot plant but also under the EAGLE project. These technologies

development as a technology to remove particulate matter fromhigh-temperature

dust

collection

methodisare also expected to be used at a 250MW IGCC demonstration

hot gas for pressurized-bed combustion and integrated

unit slated for initial operation in 2007.

gasification combined-cycle (IGCC) power generation processes.
This technology utilizes a multi-cyclone, a ceramic- or metalbased filter and a granular-bed method using silica or mullite toremove particulate matter. Multiple cyclones are mainly used forcoarse, imprecise removal. Those used for precision removal
include ceramic or metal filters of a cylindrical porous body into
which SiC and other inorganic materials and iron-aluminumalloys are formed (Photo 1). The filters used for this method weredeveloped by Nihon Garasu Kogyo or overseas by Paul
Schumacher.

Suchtechnologies,

evaluation/demonstration,

are

now

used

for

under

durability

pressurized-bed

combustion power generation at Hokkaido Electric Power’s
Tomatoh-Atsuma thermal power plant, with their verification tests

Photo 1 SiC ceramic filter

conducted not only for IGCC at 200-tons/day at the Nakoso IGCC

(3) Trace element removal method

Research and development: Japan Coal Energy Center
Project type: Subsidized coal production/utilization technology promotion project
Overview
Among the trace elements of coal, mercury is cited as theresearch, selected active carbon, natural inorganic minerals, andmaterial released into the atmosphere at the highest rate, andlimestone as materials that can absorb mercury. Their absorption

approximately 30% of the mercury not removed by thecharacteristics are now being evaluated. The research results

precipitators/desulfurizers is thought to be released. However,prove that if a method to inject active carbon or an FCC ash

nearly all bivalent mercury (Hg2+) is removed, leaving behindcatalyst into the flue for the removal of metal/mercury isnonvalent mercury (Hg) as the discharge matter. A method to

combined with removal at the flue gas desulfurizer, 90% or more

remove this nonvalent mercury is being actively reviewed. Theof the mercury can be easily removed.

Japan Coal Energy Center, though still in the process of basic

References

1) "Thermal/Nuclear Power Generation Companion, 6th edition," Thermal/Nuclear Power Generation Association, 2002.
2) Sato, "Design and Actual Operations of High-Temperature Electrostatic Precipitators," Thermal/Nuclear, Vol. 34, No. 4, 1983.
3) Tsuchiya et al., "Technology Development of Low Low-Temperature EP in Coal Thermal-Purpose High-Performance Flue Gas
Treatment System," MHI Technical Journal Vol. 34, No. 3, 1997.
4) "Toward the Realization of Integrated Gasification Combined-Cycle Power Generation," CRIEPI Review, No. 44, 2001.
5) Coal-Based Next-Generation Technology Development Survey/Environment-Friendly Coal Combustion Technology Field(Trace Element Measurement/Removal Technology), NEDO results report, 2003.

92

Part 2 CCT Overview
Environmental Protection Technologies (Flue Gas Treatment and Gas Cleaning Technologies)

5B5. Gas Cleaning Technology
Technology overview

1. Background
For the development of coal gasification gas-based power

efforts are now underway to develop dry gas purification

generation and fuel synthesis technologies, it is necessary totechnology that purifies hot coal gasification gas as it is.

remove sulfur compounds (H2S, COS), halides (HCl, HF), andother gas contents. As shown in Figure 1, a key application of thisCeramic
filtertechnology is found in the wet gas purification process that, after
removing water-soluble halides and other contents with a water

COS
Scrubber (dehalogenation,
deammonification)
conversion catalyst

Coalgasifier

scrubber, desulfurizes the gas with a methyldiethylamine (MDEA)
or other amine-based liquid absorbent for gas purification. Thismethod, however, requires the gas to be cooled to around room
temperature, thus losing much heat. Furthermore, the process

Sulfur recovery
equipment

becomes complex since it requires not only a heat exchanger but
also a catalyst that converts hard-to-remove COS into H2S. It is
H 2S
absorption
tower

also difficult to precisely reduce sulfur compounds to a 1-ppm level.
To solve problems relating to the wet gas purification process,

Recycling tower
Reboiler

Fig. 1 Wet gas purification process

2. Technology(1) Dry desulfurization method

Research and development: Japan Coal Energy Center; IGCC Research Association; Central Research Institute of ElectricPower Industry; Kawasaki Heavy Industries, Ltd.; Ishikawajima-Harima Heavy Industries Co., Ltd.; Mitsubishi Heavy Industries, Ltd.
Project type: Entrained bed coal gasification power generation plant, etc.
Overview
As shown in Figure 2, in the dry desulfurization process, metal

Heavy Industries, Ltd. has developed an iron oxide-based highlyoxides are reduced by coal gasification gas, and the reduced

wear-resistant granular desulfurization agent for use in a moving-

metal oxides remove sulfur compounds from the gas, and are

bed combined-desulfurization/dust collection system (Fig. 5) andthen converted to sulfides. This method can be used more thanevaluated its performance in a pilot plant capable of treating one-once by letting the sulfides react with oxygen to release the sulfur

fortieth of the coal gas produced by the the 200-ton/day Nakoso

contents as SO2 to return them to metal oxides.

pilot plant. This indicates that technologies for IGCC have alreadyThe development of this process as a technology for integrated

reached a validation stage.

gasification combined-cycle power generation (IGCC) was
promoted, with a target of reducing sulfur oxides to 100ppm orless in a temperature range of 400-500oC, where economical
Reduction

carbon steel can be used for piping. Iron oxide was selected as
the metal oxide to be used and Ishikawajima-Harima Heavy

Mt: Metal element

Industries Co., Ltd. built a fluidized-bed desulfurization pilot plant(Fig. 3) that can treat all of the coal gas, using 100-200- m ironore particles. It was verified in the 200-ton/day Nakoso IGCC pilot
plant (1991-1995). The Central Research Institute of Electric
Reproduction

Power Industry and Mitsubishi Heavy Industries, Ltd., with an eye

Desulfurization

to applications in the fixed-bed desulfurization systems (Fig. 4),
have jointly developed an iron oxide-based honeycomb
desulfurization agent. They also built, under the 200-ton/day
Nakoso IGCC pilot plant project (for coal gas production ofFig. 2 Desulfurization reaction cycle

43,600m3N/h), a pilot plant that can treat one-tenth of the amountof coal gas produced. The performance of the honeycomb
desulfurization agent is being verified. Meanwhile, Kawasaki

93

Clean Coal Technologies in JapanTo dust collector

Coal gas (from dust collector)

Gas for sulfur reduction

Dust filter
CycloneDesulfurization
agent

Heat
exchanger

Anthracite
Air

SOx
reduction tower

Reproduction tower

Sulfurcondenser

Desulfurization
tower

Desulfurization process Reduction process

Sulfurrecoveryequipment

Reduction process

SulfurAir
Carrier

To gas turbine

AshFig. 4 Fixed-bed desulfurization process

SulfurCoal gas

Excess gas

Separator

Soot/dust filter

Fig. 3 Fluidized-bed desulfurization process
Distributor

At present, a desulfurization agent that can reduce sulfur

Soot/dust

compounds to a level of 1ppm is under development for use in

To sulfur recovery
systemsuch applications as molten carbonate fuel cells, solid oxide fuelAir

cells, and fuel synthesis. At the Central Research Institute ofElectric Power Industry (CRIEPI), a desulfurization agent using

Reduction gas(coal gas)

zinc ferrite (ZnFe2O4), a double oxide of iron and zinc, has been

To sulfur recovery
systemdeveloped and found capable of reducing sulfur compounds to1ppm or less. It is now at the stage of real-gas validation. In

Coal gas

To gas turbine

1. Regeneration tower
2. Reduction tower
3. Desulfurization tower

Desulfurization
agent carrier

addition, efforts to introduce the desulfurization agent into airblown entrained-bed gasification systems have been made.
Another important subject is the application of the agent tooxygen-blown gasification gas with a high carbon-monoxide
concentration, which degrades the desulfurization agent by
allowing carbon to be separated out of it.
Fig. 5 Moving-bed combined dust collection-desulfurization process(2) Dry dehalogenation method

Research and development: Central Research Institute of Electric Power Industry
Project type: Voluntary
Overview
using a sodic compound is under development. CRIEPI

To use coal gasification gas in molten carbonate/solid oxide fuelcells and for fuel synthesis, it is necessary to remove not only

developed and tested a sodium aluminate (NaAlO2)-basedsoot, dust and sulfur compounds but also halogen compounds.

absorbent, confirming a possible reduction to 1ppm or less, but

For these applications, efforts are underway to develop a halidesuch efforts still remain on a laboratory scale as well as at aabsorption agent capable of reducing halogen to 1ppm or less.

development stage. This method faces an important problem ofAt present, a method to remove HCl/HF from gas as NaCl/NaF

how the absorbent should be reproduced or recycled.

References

1) Nakayama et al., "Development State of 3 Dry Gas Cleanup Methods in Dry Gas Cleanup Technology Development for Integrated
Gasification Combined-Cycle Power Generation," the Japan Institute of Energy Journal, Vol. 75, No. 5, 1996.
2) Shirai et al., "Coal Gasification Gas-Based Fixed-Bed Dry Desulfurization Technology Development,"the Society of Powder Technology,
Japan’s Journal, Vol. 40, No. 8, 2003.
3) M. Nunokawa et al., "Developments of Hot Coal Gas Desulfurization and Dehalide Technologies for IG-MCFC Power Generation
System," CEPSI proceedings, Fukuoka, 2002.

94

Part 2 CCT Overview
Environmental Protection Technologies (Technologies to Effectively Use Coal Ash)

5C1. Coal Ash Generation Process and Application Fields
Technology overview

1. Background and general status of generation process
Coal ash has, since it was commercialized as a cement

Powertransmission

admixture in the first half of the 1950’s, been widely used in
Steamapplications such as a raw material for cement, cement mixtures,Households/factories

roadbed material, backfilling material, and embankment material,
Steam turbine

finding its way mostly into the cement sector, particularly, as a

Generator
Transformer

clay-alternative raw material for cement.
BoilerCoal combustion methods are roughly divided as follows:

Smoke stack

Coal-fired power plant(1) Pulverized coal combustion (dry-type)
Economizer(2) Stoker firingAir
pre-heater(3) Fluidized-bed combustion

Electrostatic
precipitator(4) Circulating fluidized-bed combustion
ClinkerhopperFly ash(85-95%)

Breaker

2. Generation rate
According to a survey conducted by the Center for Coal
Utilization in 2003, the coal ash generation rate in Japan was
9.87 million tons a year, up 6.8%, or 630,000 tons, from the

Bottom ash(5-15%)

preceding year. Most coal-fired boilers for the electric utility

Graderindustry are combusting pulverized coal. In addition, in generalindustries, 132 One-MW or larger coal-fired boilers are in

De-wateringtankoperation, a majority of which combust pulverized coal. In terms

Silo

Silo

Silo

of boiler capacity (steam generation rate), 50-ton/hr or smaller
Baggerboilers are mostly of a stoker combustion type while many of the

Humidifier

Humidifier

100-ton/hr or larger boilers combust pulverized coal. Figure 2
shows changes in the rate of coal ash utilization and generation
Dump truck

from electric power utilities and One-MW or larger installed power

Ship

Truck

Jet vac truck Dump truck

Jet vac truck Dump truck

Fig. 1 Coal ash generation from a pulverized coal-fired boiler
Source: Japan Fly Ash Association

generation plants in general industries from 1993 through 2003.

3. Composition of coal ash
In Japan, 90% or more of the coal ash generated is from
Rate of utilization

pulverized coal combustion, dwarfing the 7% or so from fluidized-

Rate of generation

bed and some 1-2% from stoker combustion. The generation ratio
Coal ash (thousand tons)of fly ash to clinker ash (bottom ash) is 9:1.
As for the shape of coal ash particles, low-melting point ash isoften globular while much of high-melting-point ash isindeterminate in shape. The average grain size of fly ash frompulverized coal combustion is approximately 25 m, similar to silt
in fineness, between finer clay and coarser fine-grained sand foruse as a soil material.
The chemical composition resembles mountain soil, with two
inorganic components, silica (SiO2) and alumina (Al2O3),
comprising 70-80% of the total composition. Other than these,Yearferric oxide (Fe2O3), magnesium oxide (MgO), and calcium oxideFig. 2 Changes in coal ash generation and utilization rates(CaO) are also contained in slight amounts. In Japan, thecomposition of coal varies widely since 100 or more varieties ofcoal are imported from all over the world.

95

Clean Coal Technologies in Japan

4. Application fields
Table 1 shows the effective utilization of coal ash in FY2003 by

are not bright. To cope with a likely increase in coal ash in thefield. Usage in the cement industry is increasing annually. Of the

future, expanding utilization in other sectors will be important. In

8.38 million tons used, the cement industry accounted for 6.33

particular, the civil engineering field is expected to use more coal

million tons, or 75.5%. Recently, however, cement production has

ash because of its high potential for consuming large quantities.

been declining and the prospects for substantial future increases

Table 1 Breakdown of fields for the effective use of coal ash (2003)
Electric utilities

Total

Construction

Agriculture/
forestry/fisheries

Others

Total

Composition
ratio (%)

Rate ofutilization

Composition
ratio (%)

Rate ofutilization

Composition
ratio (%)

4,354

71.32

1,522

66.90

5,876

70.12

Cement mixture

149

2.44

159

6.99

308

3.68

Cement admixture

95

1.56

48

2.11

143

1.71

4,598

75.32

1,729

76.00

6,327

75.50

Foundation improving material

138

2.26

104

4.57

242

2.89

Civil work

103

1.69

25

1.10

128

1.53

Power supply construction

79

1.29

0

0.00

79

0.94

Roadbed material

50

0.82

110

4.84

160

1.91

Asphalt/filler material

9

0.15

0

0.00

9

0.11

Coal mine filling material

204

3.34

0

0.00

204

2.43

Sub-total

583

9.55

239

10.51

822

9.81

Construction materials (boards)

213

3.49

164

7.21

377

4.50

Artificial light-weight aggregate

0

0.00

0

0.00

0

0.00

Secondary concrete product

18

0.29

1

0.04

19

0.23

Sub-total

231

3.78

165

7.25

396

4.73

Fertilizer (including snow melting agent)

53

0.87

26

1.14

79

0.94

Soil conditioner

11

0.18

82

3.60

93

1.11

Sub-total

64

1.05

108

4.75

172

2.05

Sewage treatment agent

4

0.07

1

0.04

5

0.06

Steel making

13

0.21

8

0.35

21

0.25

Others

612

10.02

25

1.10

637

7.60

Sub-total

629

10.30

34

1.49

663

7.91

6,105

100.002,275

100.008,380

100.00Application
Cement raw material

Sub-total
Civil engineering

General industry

Rate ofutilization

Field
Cement(Unit: thousand tons)

Total

References

1) The Center for Coal Utilization, Japan (now known as JCOAL): National Coal Ash Fact-Finding Survey Report (2003 results), 2005.
2) Environmental Technology Association/the Japan Fly Ash Association Coal Ash Handbook 2000 Edition, 2000.
3) Nobumichi Hosoda: CCUJ, Coal Ash Utilization Symposium lecture collection, 1998.
4) Natural Resources and Fuel Department, the Agency for Natural Resources and Energy: Coal Note (2003 edition), 2003.

96

Part 2 CCT Overview
Environmental Protection Technologies (Technologies to Effectively Use Coal Ash)

5C2. Effective Use of Ash in Cement/Concrete
Technology overview

1. Technology overview
Research has been conducted on utilizing fly ash in the cement

early in the 1950’s, standards were established for fly ash in 1958

sector as an alternative for pozzolana. Enhanced research on theand then for fly ash cement in 1960, encouraging its widespreaduse of fly ash as a good-quality alternative to pozzolana led to its

application in general concrete structures.

first application as a concrete admixture in the late-1940’s, whenIn the meantime, fly ash came to be used as a clay-alternative

it was used for structures like dams in the United States. Thisraw material in cement in 1978 and by 2003, 70.1% of all theprocess was subsequently disseminated to other countries. In

effectively used fly ash was used in this manner.

Japan, following its commercialization as a cement admixture

2. Utilization in the cement sector
1) Utilization as a clay-alternative raw material in cement

constitute approximately 5% of the raw materials for cement but

The raw materials for cement are limestone, clay, silica, and ferrictheoretically its use could be as high as around 10%.

oxide, with clay accounting for 15% of the total composition. Coal

2) Utilization as cement mixture

ash containing silica (SiO2) and alumina (Al2O3) is also used as

Japanese Industrial Standards (JIS) specify standards for fly ash

an alternative to clay. However, coal ash contains less SiO2 andcement2, allowing the mixture to range from 5-30%. In general, flymore Al2O3 than clay, which requires that more silica be used toash can also be used as a Portland cement mixture, blended atoffset the shortage of SiO2. This deficiency limits the

5% or less.

substitutability of coal ash for clay. At present, coal ash can

3. Utilization in the concrete sector
1) Utilization as a concrete admixture

2. Pre-packed concrete

1. Dam concrete

Pre-packed concrete is a concrete product fabricated by casting

In Japan, research on fly ash as a concrete admixture started

coarse aggregate of a designated grain size into a mold or placearound 1950, with favorable results and economics through theof application beforehand and injecting mortar into voids at an

first commercial use at a dam site in 1953.

appropriate pressure. The mortar used must be one of highRoller compacted dam-concrete (RCD) is a concrete productfluidity, with little material separation, and of moderate

finished by compacting concrete of ultra-thick consistency with aexpansibility. For this purpose, fly ash is generally mixed at a rate

vibration roller. The then Ministry of Construction led independentof 25-50%.

technology development to utilize this in a concrete dam,

Applications include underwater concrete, mass concrete, andsuccessfully systematizing the trial into the RCD construction

the repair/reinforcement of existing concrete work. The

method, which was commercialized for dam construction in 1978.

substructure work for the Honshu-Shikoku Bridge also employed

In order to prevent cracks, dam concrete is generally not allowed

this construction method.

to reach high temperatures.

3. High-fluidity concreteDue to this restriction for RCD, only a portion of the cement can

Fly ash enriched concrete (FEC) is a two component-type, high-be replaced by fly ash in order to limit temperature increases.

fluidity concrete product using cement and fly ash as powder

Generally, the replacement ratio is 20-30%. As many as some 30

materials. It can contain 40% or more fly ash, providing suchdams have thus far been built employing this construction

characteristics as excellent self-filling capability requiring no

method, making it a well-established engineering method,compaction after casting, minimal cracking due to heat ofjustifying the development efforts.

hydration, which increases its long-term strength, as well as higher
durability against alkali aggregate reactions and salt/acid damage.

97

Clean Coal Technologies in Japan

Fly ash and slag concrete (FS), using steel slag and coal ash as

In addition, items with higher-performance qualities, or qualities

aggregates, is a plain concrete product developed for wave-

likely to prove effective as admixture despite their substandard

breaker superstructure works and fixation blocks/tetrapods thatstate, were added to the JIS standards3 and classified as grade 4

do not require great strength.

materials, thereby designating them with a quality suitable for

4. Industrial standards for concrete-purpose fly ash

utilization. Grade 1 fine fly ash is used as an admixture for

After evaluating fly ash as a concrete admixture it was

concrete products used as water/moisture barriers. It must be

determined that it performed well due to its ultra-fineness and the

durable, among other characteristics. Uses include ocean

limited quantity of unburned carbon. Subsequently, ultra-fineconcrete and specially-reinforced shielding material used foritems produced by an advanced analyzer were commercialized.

long-distanced pumping.

Table 1 Quality of fly ash (JIS-A 6201)

Class

Class Ifly ash3.0 or lessDensity (g/cm3)
Residue on 45 m sieve (screen sieve method) 3 (%)
Specific surface area (Blaine method) (cm2/g)

5.0 or less

8.0 or less

5.0 or less40 or less70 or less1.95 or higher
10 or less40 or less5000 or higher 2500 or higher 2500 or higher 1500 or higher
105 or higher

95 or higher

85 or higher

75 or higher

Material age: 28 days

90 or higher

80 or higher

80 or higher

60 or higher

Material age: 91 days

100 or higher

90 or higher

90 or higher

70 or higher

Flow value ratio (%)
Activity index (%)

Class IV
fly ash1.0 or less

Moisture content (%)

Fineness2

Class III
fly ash45.0 or higher

Silica dioxide (%)

Ignition loss1(%)

Class IIfly ash1. In place of ignition loss, the unburned carbon content ratio may be measured by the method specified in JIS M 8819 or JIS R 1603 to apply tothe result a stipulated value of ignition loss.
2. Fineness based on the screen sieve method or the Blaine method.
3. Regarding fineness, the results of the Blaine method are provided as a reference value for the screen sieve method.

Application for dams

Application for buildings

References

1) The Japan Cement Association: Common Cement Practices, 2000.
2) JIS R 5213-1997, 1997.
3) JIS A 6201-1999, 1999.

98

Part 2 CCT Overview
Environmental Protection Technologies (Technologies to Effectively Use Coal Ash)

5C3. Effective Use of Ash in Civil Engineering/Construction and Other Applications
Technology overview

1. Technology overview
Outside of its application in concrete, coal ash is widely used in

ash in the future due to such factors as the construction of new

the civil engineering sector for road construction, foundation

coal-fired power plants, utilization technologies are now underimprovements, back-filling, or for use in other earthwork and inactive development out of the necessity to expand the utilization

the construction sector as an artificial light-weight aggregate. Onof coal ash in the above-mentioned sectors. In order tothe other hand, in the agriculture/forestry/fisheries sector, it isaccomplish this, several challenges, including the diffusion ofused as a fertilizer or soil conditioner.

technology, the exploitation of demand, and the improvement of

To cope with the anticipated increase in the generation of coal

the distribution mechanism, must be addressed.

2. Utilization for civil engineering
1. Road construction material

2. Earthwork material

The "Outline of Asphalt Pavement"1 allows fly ash to be used as

Fly ash can be effectively used for an embankment or

an asphalt filler material, and clinker ash as a lower subbase

reinforcement material since it is lighter than common earthwork

material, frost heave depressant, and barrier material.

materials. In recent years, therefore, various technology

Fly ash can be used for the upper/lower subbase and subgrade.

development efforts6,7,8 have been made, resulting in a number

A cement stabilization treatment construction method adds flyof applications. Among these is an application using fly ash in its

ash to cement to be treated under moderate moisture content fororiginal powder state with cement added as a solidifier to coalapplication. This construction method strengthens quickly and isash, as well as fly ash’s utilization as a stabilizing material. It isstable over the long-term. Another technology2,3,4,5 has also

also granulated or processed in other ways for different

been developed to process coal ash for use as a roadapplications. Review is also underway for the intended

construction material.

commercialization of fly ash as a soil stabilizer or a construction
sludge conditioner due to its pozzolanic activation as well as its
self-hardening9 property.
Meanwhile, basic research of the elution10 of coal ash’s traceelements is continuing since fly ash’s use in earthwork must be inharmony with the environment.

Photo 1 Application for road construction99

Clean Coal Technologies in Japan

3. Utilization in the construction sector

4. Utilization in the agricultural/forestry/fisheries sector

1. Artificial light-weight aggregate

1. Fertilizer

Development efforts11,12 have successfully produced technology to

Fly ash, from pulverized coal-combustion ash, was designated aspelletize/calcine coal ash and cement or the like into artificial light-

a special fertilizer in 1960, as was clinker ash in 1992. Several

weight aggregate. Demand, driven by urban development and high-thousands of tons a year of potassium silicate fertilizer,

rises, is expected to grow, making it important to further thecontaining hard-to-dissolve silicic acid contained in coal ash, istechnological development of artificial light-weight aggregate as

also produced.

well as to reduce production costs.

2. Soil conditioner

2. Others

Clinker ash, whose chief components, SiO2 and Al2O3, are

The resemblance of coal ash’s elements to the chemicalalmost the same as those of ordinary soil, is suitable for thecomposition of existing construction materials also allows it to be

growth of vegetables. Moreover, it is used to grow sod for golf

used as a clay-alternative raw material for ceramic products, suchcourses or to improve the soil of poor-drainage areas or arable

as clay roofing, bricks, and tiles, or as a cement mixture for boards

land since its countless spores retain water well, enabling(interior/exterior wall material for construction).

fertilizers to be effective for a longer duration and, at the sametime, its similarity in shape to sand provides comparable water
permeability.
3. Utilization in the fisheries sector
There are long-established cases where coal ash has been used
for fish breeding reefs and seaweed beds. A recent effort aims touse coal ash as a mounding material for a man-made undersea
mountain range to cause artificial upwelling currents.13

Photo 2 Artificial aggregate fabricated from coal ash (Toughlite)

Photo 3 Application as fertilizer

References

1) The Japan Road Association: Outline of Asphalt Pavement, 1992.
2) Environmental Technology Association/The Japan Fly Ash Association: Coal Ash Handbook 2000 Edition, 2000.
3) Public Works Research Institute: Public Works-Related Material Technology/Technical Review Certification Report "Ash-Roban," 1997.
4) Public Works Research Institute: Public Works-Related Material Technology/Technical Review Certification Report "Pozzotech," 1997.
5) Ohwada et al., 11th Annual Conference on Clean Coal Technology lecture collection, 2001.
6) Shintani et al., CCUJ, Civil Engineering 54th Annual Academic Lecture Meeting, collection of summaries, 1999.
7) Public Works Research Center: Public Works-Related Material Technology/Technical Review Certification Report "Hard Soil-Break Material," 2000.
8) Akira Onaka: The Clean Japan Center’s 11th Resources Recycle Technology Research Presentation Meeting, collection of lecture papers, 2003.
9) Ozasa et al., CCUJ, 11th Annual Conference on Clean Coal Technology lecture collection, 2001.
10) The Japanese Geotechnical Society: Research Committee Report on Utilization of Wastes as Foundations Material, 2000.
11) Ishii et al., The "Bulletin of the Chemical Society of Japan," 5, 431, 1992.
12) Ozasa et al., CCUJ, 10th Annual Conference on Clean Coal Technology lecture collection, 2000.
13) Tatsuo Suzuki, 14th ACAA International Symposium lecture collection, 2001.

100

Part 2 CCT Overview
Environmental Protection Technologies (Technologies to Effectively Use Coal Ash)

5C4. Technology to Recover Valuable Resources from Coal Ash
Technology overview

1. Technology overview
Various R&D activities are being conducted to identify anddesulfurization agent, a rust inhibitor, and as an admixture anddevelop effective coal ash utilization technologies. Potential

filler for polymeric materials (rubber and plastic). Throughtechnical applications that have been studied include thezeolitization, additional potential applications have been

recovery of valuable resources from coal ash through physicalidentified, including utilization as an adsorbent, a catalyst, an ion-and chemical treatments, and the utilization of coal ash as aexchanger, and a desiccant.

2. Valuable resource recovery
Coal ash contains valuable substances including cenosphere(1) Direct hydrofluoric acid extraction method(hollow ash), magnetite silica, alumina, iron oxide, and titanium

An acid extraction method, which uses an acid mixture ofoxide, as well as trace amounts of other valuable metals.

hydrofluoric acid and hydrochloric acid, has been developed to1) Recovery of valuable resources through physical treatment

recover valuable resources from fly ash. The SiO2 recovered isMagnetite recovery through magnetic separation

characteristically of high purity (99.9% or higher) and fine

The recovery of magnetite (Fe3O4) from fly ash is performed priorparticles (1 m or less).

to the chemical treatment process to recover valuable elements(2) Calcination method

such as Si, Al, Ti, and Fe. Magnetite, recovered through a

In the calcination method, calcium is combusted with fly ash to

magnetic separation process, can be used, for example, as anconvert the acid-stable mullite present in the fly ash into acid-alternative to a heavy separation medium.

soluble anorthite or gehlenite, resulting in a high recovery rate of2) Recovery of valuable resources through chemical treatment

AI.

3. Artificial zeolite
Zeolite is a generic term for hydrated crystalline alumina silicate

zeolite production in 1990. In this coal ash zeolite production

that, as one of its characteristics, has a porous structure andprocess, coal ash zeolite is obtained when coal ash is boiled withtherefore a large specific surface area. It also contains ion-

sodium hydroxide and stirred. Solid contents are then separated,exchangeable cations and crystallization water that can be

washed and dehydrated. The zeolite produced is of an Na-P type.

adsorbed/desorbed. Because of such characteristics, zeolite can

Meanwhile, coal ash zeolite production processes commercialized to

be used, for example, as an adsorbent, a catalyst, or adate are of a batch method, similar to non-coal ash processes,

desiccant1.

while flow-through continuous synthesis processes have also

Treating a coal ash-alkaline aqueous solution mixture2

been developed4. In addition, applications that are expected tohydrothermally produces various kinds of zeolite, depending

use a large volume of zeolite are now being reviewed, with anupon the reaction conditions.

eye on reducing production costs and developing technology to

The Clean Japan Center3 conducted demonstration tests at asynthesize zeolite in ways suitable to each application.

10,000 ton/year-scale demonstration plant built for coal ash

Coal ash
Caustic soda

Boiling/
stirring

Buffer tank

Drain water

Washing

NaOH drainage pit

Dehydration

Water drainage pit
Water treatment facility

Fig. 1 Coal ash zeolite production process

101

Primary
product
storageDrying

BaggingClean Coal Technologies in Japan

4. Utilization in other sectors
1) Desulfurization agent

an alternative to plastic admixtures including calcium carbonate,

Dry desulfurization technology using coal ash has beensilica, alumina, wood flour, and pulp.

commercialized, using a hardened mixture of coal ash, slack3) Otherlime, and gypsum, which have excellent desulfurization

Other than the above, technology development is currently

capabilities.

focused on coal ash characteristics-based applications, such as2) Admixture/filler for polymeric materials (including rubber and plastic)in an agent to prevent rust caused by oxidation in steel-making,Fly ash, since it is a collection of small, round glass-bead-like fine

as well as for use in water purification or for casting sand.

particles, is being studied for possible use as a rubber filler or as

StructureA

Molecular formula

Pore size(A)

Na 12 [(AlO 2 ) 12 (SiO 2 ) 12 ]Na type: 4

27H 2 O

Ca type: 5

Pore volume
CEC(cc/g)(meq/100g)

Na type: 0.3

548

SiO4

P

X
AlO4

Na 6 [(AlO 2 ) 6 (SiO 2 ) 10 ]Na type: 2.6 Na type: 0.36

15H 2 O

514
(The figure is large
but the exchange rateis small.)

Na 86 [(AlO 2 ) 86 (SiO 2 ) 106 ]Na type: 7.4 Na type: 0.24

264H 2 O

473

Cation-containing aluminosilicate found in different forms for different structures/compositions,with each having its own characteristics and applications.

References

1) Environmental Technology Association/The Japan Fly Ash Association: Coal Ash Handbook 2000 Edition, 2000.
2) Akio Itsumi: Japan Soil Science and Plant Nutrition, 58 (3), 1987.
3) The Clean Japan Center: Clean Japan, 86, 1991.
4) Masahiko Matsukata: CCUJ, 12th Annual Conference on Clean Coal Technology lecture collection, 2002.

102

Part 2 CCT Overview
Basic Technologies for Advanced Coal Utilization

6A1. Modeling and Simulation Technologies for Coal Gasification
Research and development: Japan Coal Energy Center
Project type: NEDO-commissioned projectTechnology overview

1. Overview of basic technology for advanced coal utilization (BRAIN-C)
The consumption of fossil fuel impacts the environment in a

the above-mentioned basic data. On the other hand, it can also

variety of manners. There is also an impact on the environment

be used to evaluate and select useful basic data. With this taken

during the coal production, transportation, and utilization

into consideration, technology development under BRAIN-C has

processes. During utilization, in particular, coal dust, ash dust,

proceeded from the aspects of both useful basic dataacid gases (NOx, SOx), and carbon dioxide are discharged,

retrieval/storage as well as high-precision numerical simulation.

raising concerns of what the unregulated consumption of coal

Figure 1 shows the "BRAIN-C technology map." Results from thismay possibly have on the environment. However, technologies toproject are roughly grouped into the following three categories:

minimize the harmful impact coal utilization has on the(1) An entrained-flow gasification simulator

environment, collectively called clean coal technology (CCT), are(2) A predicted model/parameter correlative equationin widespread use in developed countries, including Japan. Given(3) A coal database

this, the "Basic Technology Development Program for Advanced(1) to (3) above are illustrated below and each is as an integral

Coal Utilization (BRAIN-C)" is focused on coal gasification

part of the results from this project, indispensable for actualtechnology and the rapid commercialization of new high-usage in a variety of situations. The appropriate utilization of each

efficiency and clean coal utilization technologies, such as coalin accordance with the application allows for full optimization.

gasification and pressurized fluidized-bed processes. Basic coaldata, from a variety of perspectives, has also been collected andcompiled. Numerical simulation is a very effective tool to predictthe characteristics of a pilot or actual production unit by utilizing

Volatilization modelTrace element data
CPC actual measurement data

Volatile contents release data

Basic database

Volatile contents database
Typicaltemperature history

Char reaction data
Reaction database

Volatile contents
Trace element
composition in quantitylta distribution modelica re da
p
y
T atu
r
pe
Equilibrium modeltem

Reaction
temperature
constant

Coal composition
Composition database(coal and char)+General analysis+Particle size-surface area
+Special analysis
CCSEM, XRD, EDS

Gasification simulation code

Parameter
correlative equation+ RESORT+ FLUENT
Growth flow
temTypicpe alda ratur determination model
ta e

ter

me

ara

p
tion

programia

Rad

Heat transmission coefficient
Heat transmission test data
Particle radiation data

Particle size
density fluctuation modelFig. 1 BRAIN-C technology map

103

Adhesiondetermination equation
Adhesion dataClean Coal Technologies in Japan

2. Entrained-flow gasification simulator
An entrained-flow gasification simulator, based on thermal fluid
analysis software, computational fluid dynamics (CFD), andSimulation program(For entrained-flow gasification)

capable of simultaneously analyzing flow, reaction, and heattransmission, can calculate temperature distribution, ash

Design: Furnace design
Operation: Operating
conditions
Coal: Properties

adhesion locations, gas composition, etc., within a gasifier if
given, as input data, such parameters as reactor shapes,
operating conditions, coal properties and reaction data (Fig. 2).
Highly reliable prediction results can be used for evaluating
operating condition validity, reactor design, and other informationin advance.

Pre-test judgment ofoperational validity

In the BRAIN-C program, the coal gasification reaction model
shown in Figure 3 and the particle adhesion model shown in

Ash adhesion position Temperature distribution CO concentration

Figure 4 are built within CFD in order to establish technology foran entrained-flow gasification simulator. Simulation results arethen compared with gasification furnace operating data in coal-Fig. 2 Functions of entrained-flow gasification simulator

based hydrogen production technology (HYCOL or EAGLE) toexamine the validity.
Gas-phasereaction

Product gas

Volatile contents release speed
Oxidizing agent
Volatile contents

Fixed carbon
AshFixed carbon

Gasification speed
Gasification database

Ash

Ash

Fig. 3 Coal gasification process modeling

Particle viscosity:

Particle adhesion prediction conditions
Predicted
value

Reflection
Predicted
valueAdhesion

Wall ash layer viscosity

Fig. 4 Ash viscosity-based adhesion prediction model

104

Part 2 CCT Overview
Basic Technologies for Advanced Coal Utilization

Figure 5 shows an example of the comparative results between

particles can hardly adhere. On the other hand, the near-wall

the formation position of a fused ash layer and the internal

temperature and ash viscosity on the wall shown on the right side

condition of a gasifier after operations. This showed that theof Figure 6 are the result of simulation under intentionallyformation position of the fused ash layer as predicted by themodified operating conditions. For this case, the oxygen ratio at

simulator corresponded well to the position where the fused ash

the top of the chart is higher and that at the bottom is lower thanlayer actually existed, confirming the accuracy of the simulationis shown on the right side of the figure. In such cases, it was

relative to the actual data.

found that the temperature at the bottom of the furnace

Figure 6 shows the result of case studies on HYCOL using adecreases (shown in orange) and the low-ash-viscosity region

gasification simulation. The near-wall temperature and ash(shown in blue) narrows while the upper part of the furnace

viscosity on the wall shown on the left side of Figure 6 are thosebecomes hot (the region in red increases) to form a region where

reproduced by simulation after 1,000 hours of operation. The

it is easier for ash to adhere, categorized as less desirable

temperature of the bottom area of the furnace (shown in red inoperating conditions.

upper image) into which slag flows are high versus the low ash

By using the gasification simulator in this manner, analysis canviscosity in the bottom area of the furnace (shown in blue in thebe easily made even if gasification conditions are altered. This

lower image). The temperature of the upper part of the furnace is

has resulted in growing expectations for use of the simulator inlow (shown in green in upper image), providing conditions where

future gasification projects.

Case 3 Forecast value
Near-wall temperature
Temperature:highGrowth of slag

Temperature:low

Throttled section
Ash viscosity on the wall
The low-viscosity
region at the
top expands.

Pressure
detection terminal
Amount of adhesion= amount of slag discharged

A high-viscosity
region at thebottom appears.

Molten slag

Fig. 5 Ash adhesion position verification results

Fig. 6 Simulator-based studies

3. Predicted model/parameter correlative equation
The entrained-flow gasification simulator can be applied toequations for estimations and experimental conditions). Morevarious furnace designs and operating conditions, but it is not

specifically, a generalized volatilization model and the adhesion

applicable to all types of coal. It is, therefore, necessary to input

determination equation are among the tools to prepare

coal characteristics into the simulator by coal-type as aparameters. In the meantime, a trace elements distribution model

parameter. This parameter generally uses the data obtained fromand an adhesion determination equation model offer determinations

basic test equipment but, from the vantage of obtaining a prompt

from simulation results, playing another important role. Under theevaluation, it is desirable to establish a means to obtain the

BRAIN-C, therefore, prediction equations around a gasification

parameters from a general analysis of coal or from structural

simulator have also been developed so that the simulator can becomposition data (an advanced model incorporating correlative

used effectively and quickly.

105

Clean Coal Technologies in Japan

4. Coal databaseThe

developmentofacorrelativeequation

or

model

indispensably requires physical and basic experiment data,
including general analysis data. There is, however, a significant
issue in that the characteristics of coal differ by lot, even if the
20-liter containers

coal has come from the same coal mine. It was, therefore, firstnecessary for each testing body that obtained physical and basic
data to use exactly the same coal samples. Figure 7 shows acoal sample bank built within the National Institute of Advanced
50-liter containers

Industrial Science and Technology. Such unified management ofanalytical test samples has enabled the shipment of identicalsamples to all testing research bodies.

Standard sample coal storage (AIST)

As far as the identical sample-based data is concerned, themeasurement of typical data will be completed under this projectfor 100 types of coal for general/special analysis data, and for atleast ten types of coal, depending upon the data criteria, for basic
experiment data. Eventually, all of this measurement data will becompiled in an Internet-accessible coal database. Some of thedata thus far obtained, as shown in Figure 8, has already been
uploaded to JCOAL’s server and is accessible or retrievable.
Much of this data is stored in an easy-to-calculate/process Excel
file (Fig. 9) and can also be downloaded.
Standard sample coal (for delivery)
Fig. 7 Coal sample bank

100
100 types
types ofof coalcoal
GeneralGeneral analysis/special
analysis/special analysis
analysis

Reaction
Reaction data,data, etc.
etc.

Reaction
Reaction data,data, etc.
etc.

Spreadsheet
Spreadsheet file
file download
download

On-lineOn-line retrieval
retrievalFig. 8 Coal database

Fig. 9 Basic data acquisition

5. Dissemination of basic coal utilization technology products
An entrained-flow gasification simulator thus far developed underworkshops for the purpose of encouraging the optimal utilization

BRAIN-C is capable of making practical predictions through theof these products, were also being prepared.

utilization of various models and basic data. The BRAIN-C

Despite the predominance of coal gasification technology in thisProject, finished in 2004, developed a well-equipped system todevelopment project, other types of gasification projects are strongly

make a wide selection of programs and basic data available soencouraged to use the simulation code, since it can be widely usedthat the products developed under this project could be used

for combustion simulation as well as in other applications.

without limitation. Detailed service manuals, as well as

106Part 2 CCT Overview
Co-production Systems

7A1. Co-generation Systems
Technology overview

1. Definition of co-generation
A co-generation system is a system using a common energy
source to produce both electricity and thermal energy for otheruses, resulting in increased fuel efficiency.
2. Co-generation systems
Co-generation systems are roughly divided into two types. One is

The former generally uses liquid or gas fuel and is often small-a type that powers a diesel engine, gas engine, gas turbine, or

scale for hotels, supermarkets, and hospitals.

other motor to generate power while recovering the waste heat

As for the latter, every type of fuel, including coal, is used as fuelfrom the motor as hot water or steam through a thermal

for boilers and many are found as relatively large-scale industrial-exchange at a boiler. The other type involves generating power by

use thermal power plants. Systems are further grouped into ones

rotating a steam turbine with steam produced by boilers andthat mainly supply electricity (condensing turbines) versus thoseremoving steam of a desired pressure as process steam.

that mainly provide steam (back-pressure turbines).

Electricity

Jacket cooling water

Hot water

Diesel orgas engine

Waste heatrecovery boiler

Heating
Hot water supply

Cooling water
heat exchanger
Steam

Generator

Electricity

Process steam

Stack

Fig. 1 Overview of a typical diesel/gas co-generation system

3. Efficiency
In general, the power generation efficiency of a coal thermal

wholesales/supplies electricity as an independent power

power generation plant producing only electricity is around 40%.

producer (IPP). Electricity generated from the No. 1 unit, which

On the other hand, the overall thermal efficiency of abegan operating in April 2002, and the No. 2 unit, which begancogeneration system, which combines power generation

operating in April 2004, are all being delivered to The Kansai

efficiency and heat recovery efficiency, depends upon whether its

Electric Power, Inc.

main purpose is to supply electricity or to supply heat. Co-(2) Regional supply of heatgeneration systems that primarily supply heat can reach

A portion of the steam from the Kobe plant to be used for power

efficiency levels as high as 80%.

generation is extracted in order to supply up to a maximum of 40(1) Co-generation at a large-capacity coal thermal power plant

tons/hr to four nearby sake-breweries. This amount, accounting

Kobe Steel’s Shinko Kobe Power Station, a 1,400MW (700MW x

for approximately 2% of the steam generated in the boilers,2

indicates that the share of heat supplied is small. Previously, eachgenerators),large-scalecoal

thermalpower

plant,

107

Clean Coal Technologies in Japanbrewery had produced its own steam. Now, however, the power
plant’s secondary steam is extracted at the steam header anddirectly supplied to the breweries. By using steam extracted
from the power plant, regional energy conservation efforts are
realized.
(3) Heat supply conditions
Steam extracted from the turbine of the power plant contains
trace amounts of a rust inhibitor called hydrazine and, therefore,cannot be directly supplied to breweries since the steam used in
the breweries comes into direct contact with rice. Secondary
steam, produced indirectly using a steam generator powered byturbine extraction steam (primary steam), is therefore supplied
to breweries. An overview of Kobe Steel’s Shinko Kobe Power
Station is shown in Photo 1.

Photo 1 View of Kobe Steel’s Shinko Kobe Power Station

No. 1 power plant
Steam
Boiler

TurbineGenerator

Extracted
steam
Feed water

Cooling water(Sea water)

Primary steam
Breweries

BackupNo. 2 power plant

Secondary steam

Sawanotsuru
Fukumusume

Steamgenerator

Hakutsuru
Industrial
water

Drain cooler
Industrial
water tank

Gekkeikan

Water supply processing

Fig. 2 Process flow of heat supply facility

References

1) Shibamoto et al., Featured Thermal Power Plant Thermal Efficiency Improvement, Article 3 Thermal Efficiency Management Trend;
Thermal Control for a Power Generation System, pp. 1242-1246, Vol. 54, No. 565, Thermal/Nuclear Power Generation, Oct. 2003.
2) The Thermal and Nuclear Power Engineering Society: Introductory Course IV. Industrial-Use Thermal Power Facilities, Etc., pp. 15391546 Vol. 54, No. 567, Thermal/Nuclear Power Generation, Dec. 2003.
3) Kida et al., Outline of Power Generation Facilities at Kobe Steel’s Shinko Kobe Power Station, pp. 2-7, Vol. 53, No. 2, Kobe SteelTechnical Report, Sept. 2003.
4) Miyabe et al., Kobe Steel’s Shinko Kobe Power Station Surplus Steam-Based Heat Supply Facility, pp. 14-18, Vol. 53, No. 2, Kobe
Steel Technical Report, Sept. 2003.

108

Part 2 CCT Overview
Co-production Systems

7A2. Co-production Systems
Technology overview

1. Feasibility of fuel co-production power generation systems
Conventional attempts to develop innovative processes within a

and assembling peripheral plants to produce various products,

single industry face limitations. To continue the reduction of CO2enhances the unification of industries centered on a core plant,emissions, it is necessary to comprehensively review existing

thus forming an industrial coal complex based on a new materialenergy and material production systems and to develop

and energy production system. This unification of industries

technologies that optimize the individual processes and thewould advance existing industrial systems to a next-generation,interface between processes. This will not only improve thehybrid industrial system.

conversion efficiency and conserve energy, but will also

The core technology for that type of fuel co-production power

fundamentally and systematically change energy and material

generation system is coal gasification technology. By combining a

production systems.

high-efficiency power generation system, such as IGFC, with a

The "fuel co-production power generation system," which

process to co-produce storable fuel, the normalization of the load

produces power, fuel, and chemicals from coal, improves the total

to the gasification reactor and a significant reduction of CO2

energy use efficiency through the unification of industries throughemissions are attained.

the construction of an industrial coal complex.

Furthermore, the waste heat in the industrial coal complex is

In the power, iron and steel, and chemical industries, where large

utilized to recover chemicals from coal through endothermic

amounts of coal are consumed to produce energy, structuring areactions, thus further improving energy efficiency and enhancing

core plant that produces energy and chemicals simultaneously,

the industrial coal complex.

Steam boiler in new or existing facility

Steam

ST
GT
FC

Gasification Center
Coal + Biomass(Waste,waste plastics,
oil-based residue, etc.)

Coal

Coal

Power

H2, CO

Fluidized-bed
gasification furnace

Spouted-bed
gasification furnace

Thermaldecomposition furnace

Process steam
H2

Non-reacted
gas

Fuel for heating

For fuel cell power generation,refineries, chemical plants

For hydrogen production

DME market

DME

For petrochemical plants
Propylene
C2 distillate
C4 distillate

H2, COH2

For hydrogenation anddesulfurization at ironworks

H2, COFor iron works
BTX, etc.
For petrochemical plants
CH4

Petrochemical plants, gas companies
Fig. 1 Energy flow

109

Clean Coal Technologies in Japan

2. Co-produced fuel and raw materials for chemicals
There are overseas examples of fuel and chemicals being co-

anticipated that DME, which has applications as a raw material

produced along with power through coal gasification, withfor clean fuel and for propylene production, will be produced as

production varying depending on the needs of the related

will hydrogen, for which demand is expected to increase for use

companies, like Sasol’s production of synthetic fuel (GTL) in

as a fuel for fuel cells and for the coming hydrogen-oriented

South Africa and Eastman Chemical Company’s production ofsociety.

acetyl chemicals in the U.S. Other examples of chemical

Clean gas for iron works is also expected to be produced tosynthesis with coal gasification include the production of

respond to changes in the energy balance at iron works of themethanol and methane in China, Europe, and the U.S. It is

future.

3. Co-production systems
The co-production system produces both materials and energy toas power and fuel, while also producing materials shall besignificantly reduce the exergy loss that occurs mainly in theencouraged from the perspectives of creating new energy

combustion stage, and achieves an innovative and effective use

markets and also creating new industries.

of energy.

Coal co-production systems focused on coal gasification will be

The co-production system is a new production system thatable to solve environmental issues through a significant reduction

combines aspects of the conventional system, which aims toin CO2 emissions by realizing the development of high grade andimprove energy conversion efficiencies, and the cogeneration

comprehensive coal utilization technology. That type of systemsystem, which effectively uses the generated thermal energy totechnology development would trigger strong technologicalthe maximum extent possible, but goes one step further byinnovation in the coal utilization field, and vigorous innovation is

producing both energy and materials in order to significantly

expected

reduce their consumption. The co-production system, which

encourage the structuring of a recycling-oriented society.

should stimulate the economy, is also clean, thereby solving bothInternationally, the development of co-production systems shouldenergy issues and environmental concerns simultaneously.

be an important technological issue that addresses global

Consequently, co-production systems that produce energy, suchenvironmental issues.

toincreaseinternational

competitiveness

FuelPower generation in existing steam turbine power generation systems
Power
Fuel for power
generation

Power Steam

IGCC for industrial complex
Private power generation at iron works GT-CC
Cooperative thermal power company GT-CC
BTX, etc.

Outside
sale
Steam

Gas
Recovered steam

Iron works
Fuel for heatingGas, power, steam, BTX, etc.

Shift reaction

Coal yard
waste

Process steam
Fuel for heating

Residue oil

H2/CO > 2
H2 separation
HydrogenDME production

Non-reacted gas

Fluidized-bed
gasification
reactorIndustrial petroleum complex

Spouted bed gasification reactor Gas
Thermal decomposition reactor

Un-recovered gas
For hydrogenation

Outside saleFig. 2 Power generation, steam, fuel for process heating, hydrogen, and DME energy supply system in an iron works facility

110

and

Part 3 Future Outlook for CCT
Future Outlook for CCT

Looking ahead to the future of clean coal technology from theviewpoint of technical innovation in the coal industry, noted below

65

Power generation efficiency [%]are some very diverse technological trends that are crucial forsociety.
The first trend is that many different technologies or systems
related to coal gasification are now under development. As an
example, R&D on high-efficiency power generation systems,
including the integrated coal gasification combined cycle (IGCC)
and the integrated coal gasification fuel cell combined cycle(IGFC), has steadily progressed toward commercialization.
Another example is conversion into liquid fuel or chemical raw

A-IGFC up to
65%

60
55

IGFC 55%
IGCC 1500oC-class
GT wet gas cleaning 46%
IGCC demonstration
unit 1200oC-classIGCC
A-PFBC 1300oC-class GT 46%
GT dry gas cleaning 40.5%
1500oC-class
GT dry gas cleaning 48%

50

45

40
2000

materials that are clean and contain no impurities, such as

A-IGCC 1700oC-class
GT 57%

A-IGCC 1500oC-class GT 53%

2010

2020

2030

Year of commercialization

methanol, DME and GTL. These technologies will lead to coproduction systems, including co-generation, with a view to a

Fig. 1 Projection of improvement of generation efficiency

zero-emission world.

Source: The Institute of Applied Energy

Diesel, naphthalene, etc.

IGCC/IGFC

Electric power

Methanol, acetic acid, etc.

Hybrid gasification of coal,biomass, waste plastics, etc.

BoilerChemicals
DME, GTL

Oil

Coal

Power plant, automobiles, etc.

Co-production manufacturing:raw materials for chemicals

Biomass

Synthesis gas (H2, CO)

Gasification

Commercial,transportation

Co-production manufacturing:
reduced iron

Waste plastics

Reduced ironHydrogen stations
Fuel cell vehicles

H2 production, CO2
separation and recovery

Iron and steel

Gasification furnace

Blast furnace

Stationary fuel cells

Slag

H2

CO2
Effective use
Storage
Blast furnace

Fig. 2 Various CCT developments centering on coal gasification

The second trend is towards efforts to build a hydrogen energy

100.0

society, which is the direction the energy sector is expected to move.
HydrogeneconomyAccording to the International Institute for Applied Systems Analysis
2000 (IIASA 2000), in terms of the "H/C (hydrogen/carbon)" ratio,
10.0

global primary energy consumption was on a near-constantGas: H/C = 4

H/C

increase between the mid-1800’s to around 1980. In and after
1980, the H/C ratio remained almost unchanged at around two

1.0

pre-1980 trend is expected to resume, leading to a situation

Methane economy

Oil: H/C = 2

due to an increase in oil consumption. As a whole, however, theCoal: H/C = 1

where, around 2030, the H/C ratio will equal four. In a society
where the primary energy source is shifting from natural gas tohydrogen, energy consumption derived from carbon combustion
0.1

will finally be discouraged. It is even predicted that coal energy

1800

will only be used for HyPr-RING (Hydrogen Production by

1850

1900

1950

2000

2050

2100

Fig. 3 Ratio of hydrogen to carbon (H/C) in primary energy
Prepared from IIASA 2000

111

Clean Coal Technologies in Japan

Reaction Integrated Novel Gasification process, where the H/Cgenerated through the direct combustion of coal and to collectratio is approximately one), and society will be forced to deal with

crude oil and gases. The other is to build high-efficiency coal

CO2 emissions resulting from the direct combustion of coal byutilization technologies, including coal gasification, reforming andheavily relying on CO2 separation, recovery, sequestration andconversion technologies, so that the carbon component in coalfixation. Thus, there are basically two important clean coalcan be used as fuel or as a feedstock for the chemical industry,technology challenges. One is to develop a series of upstream

thereby reducing CO2 emissions generated through directtechnologies to separate, recover, sequester and store CO2

combustion.

Separation/recovery

Sequestration/storage

Gas after decarburization
CO2 concentration 2%

Separation/recovery
Pressure injection from a facility on the sea
Pressure injection froman above-ground facility
Tanker transport
Discharged
CO2 concentration
22%

Separated/recovered
CO2 concentration99%
Cap rock(impervious layer)

Sources from which CO2 is discharged

Dissolution
diffusion
Pipeline carriage(including power and steel plants)

CO2
Underground aquifer
Coal bed

Separation/recovery

Transportation

Sequestration/storage-Chemical absorption method-Physical absorption method-Membrane separation method-Ground: Pipeline
after liquefied-Sea: Liquefied CO2transport vessel-Underground: Aquifer
Coal bed-Ocean: Dissolution/diffusion oras hydrates (onto the sea floor)

CO2

Fig. 4 CO2 separation, recovery, sequestration, and storage

The third trend is exploiting coal technology’s potential fordevelopment of hyper-coal production technology may bringtechnical development in association with innovative technologies

about novel techniques that allow advanced utilization of thesuch as environmental/energy technology, biotechnology,

carbon within coal. In fact, there exist some specificnanotechnology and information technology, which have been

nanotechnology areas, such as nanocarbon fibers, wherecategorized as priority R&D target technologies in Japan.

potential technical innovation is associated with coal.

Research and development of environmental/energy technology

The progress in information technology will certainly bring about

is focused on achieving a zero-emission society, mainly throughinnovative developments in the modeling and simulation of coal

the implementation of "CO2 control," as mentioned earlier. The

technologies.

co-production system is regarded as the final target to beachieved through technical innovation.
Advances in biotechnology could also unlock methods for the

Steel

Chemicals

Other
by-products

Cementfixation and effective utilization of CO2. Furthermore, theSteel-making plants

al
ic

es
s

m

pr
oc

he

C

ts
an

ok
in

g

Light
energypl

Energy and materials linkage between industries

Fuel(gas/liquid)C

Rawmaterial

Hydrogen

Fuel cell vehicle

Iron and steel works
IGCC

ChemicalenergyIGFC

CO2 recovery

Reformed coal
CO2 sequestration

Coal

Air/watern/ ss
tio ce
ac o
ef pr
qu is
Li lysropy

USC

Energy conversion system

Electric & magnetic
energyts

Electric power

Joul

en
tp

Waste, waste plastics Power plantCoal(solid fuels)

Heat
energyem

SCOPE21

Advanced gasification
furnace

HyPr-RING

Dynamic
energylanIron and steel
Blast furnace

C

Chemicals,
other

Coal partial hydrogenation

Power plants

Hydrogen station

Coal gasification

Gasification/
combustion process

Biomass

Environmental facilities

USB

ExhaustFig. 5 Energy utilization in a future society supported by CCT (2030)

Drainage

Waste heatFig. 6 Co-production system
The ultimate goal for co-production systems is zero emissions(or the discharge of purified water and steam).

112

Electricity

Heat(steam/hot water)

Part 3 Future Outlook for CCT
Future Outlook for CCT

Clean Coal Technologies in Japan

CCT plays an important role in steelmaking as well as in power

Mechanisms, including the Clean Development Mechanism

generation. Coal is used in the steelmaking industry not only as(CDM), which seek to address global environmental problems.

an energy resource but also as a high-quality reducing agent,

Economic growth can only be achieved with a stable supply ofand is one of the raw materials used in steelmaking. A potential

energy, while environmental conservation is a challenge to betask to be assigned to well-established steelmaking processes,

addressed by the whole world. The former is a limiting factor forsuch as the blast-furnace process, is to achieve an innovative

the latter and vice versa. Throughout history, these twolevel of total coal utilization efficiency by using a co-production

conflicting concerns have had the common fundamental problem

system, like DIOS (Direct Iron Ore Smelting reduction process),of explosive population growth. Under these circumstances,in order to simultaneously produce iron and synthetic gas,efforts for environmental conservation, including controllingelectric power, hydrogen/thermal energy, chemical feedstocks,

global warming with a goal of eliminating emissions, must be theetc., from steam coal for the steady implementation of improved

top priority in the development of CCT in Japan. It is, therefore,

environmental measures aimed at zero emissions.

essential to build an efficient, advanced coal energy utilization
system with minimum impact on the global environment, which
will require international cooperation.

As the world’s largest coal importer and as the leader in CCT,
Japan should remain active in international cooperation,
including technical transfers and human resource developmentwith developing countries, mainly in Asia. Such international
activities will not only benefit countries that are trying to improvetheir economic growth by relying on coal energy, but also provide
Japan itself with significant means to achieve a stable supply ofenergy. In addition, it will support efforts to utilize the Kyoto

Promotion of innovative CCT development toward eliminating emissions
With an aim to positioning coal as a source of CO2-free energy by 2030, innovative CCT development will be promoted, including
CO2 fixation technology and next-generation high-efficiency gasification technology, toward the goal of eliminating emissions, while
identifying the role of individual technologies in the overall scheme.

Unification of CO2 separation _and fixation technology

Fixation technology

Coal gasification technology

Improvement in thermal efficiency
6 yen/kWhAir-blown
gasification

6-7 yen/kWh

Demonstration testingZero-emissions
GCC commercial
unit

GFC commercial
unit

46-48%
46-48%
Power
sending
generationend efficiency
efficiency

Oxygen-blown
gasification

Research anddevelopment

55%
Power
generation
efficiency
55%
sending
end efficiency

Demonstration testing
A-IGCC/
A-IGFC

Industrial gasification
furnace

Advanced coalgasification
CO2 separation
and recovery

F/S

Research and development

Research and development

Demonstration testing

Research and development

CO2 fixation

Actualization of zero-emissions

Demonstration testing>65%>65%
sendingPowerendgeneration
efficiency
efficiency

Demonstration testing of new separation
and recovery technology

Development toward full-scale sequestration

Demonstration testing

Current coal thermal generation unit price is assumed to be 5.9 yen/kWh,as estimated by The Federation of Electric Power Companies, Japan.

113

Commercialization

(2) Prefix of SI system(1) Main SI units
Quantity
Angle
LengthArea
VolumeTime
Frequency, vibration
Mass
Density
Force
PressureWork, energy
Power
Thermodynamic temperature
Quantity of heat

SI unitradmm2m3
s (Second )Hz (Hertz )kg
kg/m2
N (Newton )Pa (Pascal )J (Joule )W (Watt )K (Kelvin )J (Joule )Unit applicable with SI unit

PrefixMultiple to the unit…(degree ), ’(minute), ’’(second)

1018
1015
1012
109
106
103
102
10
10-1
10-2
10-3
10-6
10-9
10-12

(liter)d (day), h (hour), min (minute)t(ton)bar (bar)eV (electron voltage)

Name

Symbol

Exa
Peta
Tera
Giga
Mega
kilo
hecto
deca
deci
centi
milli
micro
nano
pico

E
P
T
G
M
k
h
da
d
c
m
u
n
p

(4) Coal gasification reactions(3) Typical conversion factors
1. Basic Energy Units
1J (joule )=0.2388cal
1cal (calorie )=4.1868J
1Bti (British )=1.055kJ=0.252kcal
2. Standard Energy Units
1toe (tonne of oil equivalent )=42GJ=10,034Mcal
1tce (tonne of coal equivalent )=7000Mcal=29.3GJ
1 barrel=42 US gallons 159
1m3=35,315 cubic feet=6,2898 barrels
1kWh=3.6MJ 860kcal
1,000scm (standard cubic meters )of natural gas=36GJ (Net Heat Value )1 tonne of uranium=10,000-16,000toe(Light water reactor, open cycle)
1 tonne of peat=0.2275toe
1 tonne of fuelwood=0.3215toe

(1)
1
2

97.0kcal/mol
29.4kcal/mol

(2)
(3)

38.2kcal/mol(4)31.4kcal/mol
18.2kcal/mol
10.0kcal/mol

(5)
(6)
(7)

17.9kcal/mol
49.3kcal/mol

(8)
(9)

(5) Standard heating value for each energy source
Energy source
Coal
Coal
Imported coking coal
Coking coal for coke
Coking coal for PCI
Imported steam coal
Domestic steam coal
Imported anthracite
Coal productCoke
Coke oven gas
Blast furnace gas
Converter gas
Oil
Crude oil
Crude oil
NGL, Condensate
Oil product
LPG
NaphthaGasoline
Jet fuel
KeroseneGas oilA-heavy oil
C-heavy oil
Lubrication oil
Other heavy oil product

Unit

Standard calorific value

kg
kg
kg
kg
kg
kg

28.9 MJ
29.1 MJ
28.2 MJ
26.6 MJ
22.5 MJ
27.2 MJ

6904 kcal
6952 kcal
6737 kcal
6354 kcal
5375 kcal
6498 kcal

7600 kcal

kg
Nm3
Nm3
Nm3

30.1 MJ
21.1 MJ
3.41 MJ
8.41 MJ

7191 kcal
5041 kcal
815 kcal2009 kcal

7200 kcal
4800 kcal
800 kcal2000 kcal

38.2 MJ
35.3 MJ

9126 kcal
8433 kcal

9250 kcal
8100 kcal

11992 kcal
8146 kcal
8266 kcal
8767 kcal
8767 kcal
9126 kcal
9341 kcal
9962 kcal
9603 kcal
10105 kcal

12000 kcal
8000 kcal
8400 kcal
8700 kcal
8900 kcal
9200 kcal
9300 kcal
9800 kcal
9600 kcal
10100 kcal

kgStandard calorific value on a Kcal basis Former standard calorific value

Remarks
Temporary value

6200 kcal
5800 kcal
6500 kcalkg

50.2 MJ
34.1 MJ
34.6 MJ
36.7 MJ
36.7 MJ
38.2 MJ
39.1 MJ
41.7 MJ
40.2 MJ
42.3 MJ

Oil coke
Refinery gas

kg
Nm3

35.6 MJ
44.9 MJ

8504 kcal
10726 kcal

8500 kcal
9400 kcal

Gas
Flammable natural gas
Imported natural gas (LNG)
Domestic natural gas
City gas
City gaskg
Nm3

54.5 MJ
40.9 MJ

13019 kcal
9771 kcal

13000 kcal
9800 kcal

Nm3

41.1 MJ

9818 kcal

10000 kcal

kWh9.00 MJ

2150 kcal

2250 kcal

kWh3.60 MJ

860 kcal

860 kcalkg

2.68 MJ

641 kcal

Formerly NGLFormerly other oil productsElectric power
Generation side
Heat supplied to power generator
Consumption side
Heat produced from electric power
Heat
Consumption side
Heat produced from steam

Clean Coal Technologies in Japan

Japan Coal Energy Center (JCOAL)

January 2007

Meiji Yasuda Seimei Mita Building 9F,
3-14-10 Mita, Minato-ku, Tokyo 108-0073 Japan
Tel. +81-3-6400-5193 Fax. +81-3-6400-5207

The copyright of this brochure is owned by JCOAL and NEDO.

Formerly LNG
Formerly natural gas

Efficiency 39.98%

100oC, 1 atm
Saturated steam

New Energy and Industrial Technology Development Organization (NEDO)MUZA Kawasaki Central Tower 21F,
1310 Omiya-cho, Saiwai-ku, Kawasaki City, Kanagawa 212-8554 Japan
Tel. +81-44-520-5290 Fax. +81-44-520-5292

114

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Load Reduction
Technology

Multi-Purpose
Coal Utilization
Technology

CCT
Iron Making andGeneral Industry
Technology

Clean Coal Technology

Co-production
SystemClean Coal Technologies in Japan Technology Innovation in the Coal Industry

Technologies for
Coal Resources
Development

Clean Coal Technologies in Japan
Technology Innovation in the Coal Industry

Coal Fired Power
Generation
Technology

Basic Technology
for Advanced Coal
Utilization

Meiji Yasuda Seimei Mita Building 9F,
3-14-10 Mita, Minato-ku, Tokyo 108-0073 Japan
TEL. +81-3-6400-5193 FAX. +81-3-6400-5207
E-mail: jcoal-info@jcoal.or.jp
URL: http://www.jcoal.or.jp

Japan Coal Energy Center

Japan Coal Energy Center

Japan Coal Energy Center