1

Commercial Experience of the CT-121 FGD Plant for

700 MW Shinko-Kobe Electric Power Plant

#27

Yasuhiko Shimogama

Kobe Steel

2 Nadahamahigashi-cho, Nada-ku, Kobe, Japan

Hirokazu Yasuda

Naohiro Kaji

Fumiaki Tanaka

Chiyoda Corporation

3-13 Moriya-cho, Kanagawa-ku, Yokohama, Japan

David K. Harris

Black & Veatch Corporation

11401 Lamar Avenue, Overland Park, Kansas, USA

ABSTRACT

Shinko-Kobe Electric Power Plant was designed as an "Urban Type Plant" which must

meet stringent environmental control requirements, because this power plant is located in

the center of the Kobe City. To maintain the quality of life of the citizens, Chiyoda

Corporation was requested to provide process capabilities to meet very stringent

environmental requirements. The CT-121 FGD process can provide superior SO2 and

particulate removal performance to meet the client’s requirements as demonstrated by our

experience in existing CT-121 installations.

This paper describes the commercial experience of the CT-121 plant for Shinko-Kobe

Electric Power Plant from the following different perspectives.

 From operating experience:

- Stable SO2 removal efficiency of over 99 percent.

- High SO2 removal efficiency with low operating cost.

- High particulate removal efficiency.

 From construction experience:

- Construction cost reduction by applying the panel construction method.
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In addition to the above, the relevance of CT-121 Kobe experience to North American

applications is discussed from the following viewpoints.

 Accommodating a wide variety of fuels and inlet conditions.

 Maximizing the results of an investment in FGD technology.

 Avoiding costly particulate control modifications or upgrades.

 Reducing project costs and cost variance through panel construction of the JBR.

INTRODUCTION

Shinko-Kobe Electric Power Plant is located in the center of Kobe City, which is the fifth

largest city in Japan with a population of over one million, and is the largest IPP project in

Japan.

The CT-121 FGD process was requested to provide process capabilities which meet the

unprecedented and stringent environmental requirements imposed by the site-specific

condition.

To maintain the quality of life of the citizens, Shinko-Kobe Electric Power Plant has set up

a noble theme. The CT-121 must also play an important role to realize the theme through

its design and construction.

THEME OF SHINKO-KOBE ELECTRIC POWER PLANT

Shinko-Kobe Electric Power Plant (coal fired power generation, 2 x 700MW) has been

constructed as an "Urban Type Power Plant" under the theme of coexistence with the City.

The No. 1 power plant was put into operation on April 1, 2002, and the No. 2 power plant

is now under construction for commercial operation starting on April 1, 2004.
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Figure 1 illustrates the theme of Shinko-Kobe Electric Power Plant.

Figure 1 Theme of Shinko-Kobe Electric Power Plant

PROPOSITION REQUESTED OF THE CT-121 TO MAINTAIN

QUALITY OF LIFE OF CITIZENS

To achieve the noble theme and to maintain the quality of life of the citizens, Shinko-Kobe

Power Plant has introduced the latest environmental technologies of the highest level from

all fields including air pollution, water quality preservation, noise, vibration and odor

prevention.

In the field of air pollution control, the CT-121 can strongly boast its SO2 and particulate

removal capability to meet the client’s requirements. That is to say, it can realize a part of

the theme established by Shinko-Kobe Electric Power Plant and can play an important role

in an “Urban Type Power Plant”.

The propositions requested of the CT-121 are summarized as follows:

 Stable SO2 removal efficiency of over 99 percent.

 High SO2 removal efficiency with low operating cost.

 High particulate removal efficiency.

Urban Type

Power Plant

Effective Use

of Energy

Harmony

with Community

Coexistence

with the City
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PROPOSITIONS FROM THE OPERATING EXPERIENCE

The No.1 FGD unit of the CT-121 installations for Shinko-Kobe Electric Power Plant,

which is hereinafter referred to as “CT-121 Kobe,” has been operated for almost a year

without any trouble.

This chapter describes the operating experience of CT-121 Kobe.

Stable SO2 Removal Efficiency of Over 99 Percent

The outline of Shinko-Kobe Electric Power Plant and the basic design of the CT-121 Kobe

are shown in Table 1 and Table 2, respectively.

Table 1

Outline of Shinko-Kobe Electric Power Plant

Location Kobe City, Hyogo, Japan

Output 700MW (×2)

Fuel Coal (S in coal: 0.93 %, HHV: 10,400 Btu/lb)

Boiler Once-through boiler

Steam Turbine Condensing turbine

Generator Synchronous generator

Flue Gas Treatment ・DeNOx System : SCR process

・Dust collector : Low-low temperature ESP

・DeSOx system : The CT-121 Process

Construction Started June 1, 1999

Commercial Operation started April 1, 2002

Table 2

Design Basis and Major Equipment of CT-121

Design Condition

<Inlet>

Flue Gas Coal fired boiler flue gas

Gas Volume 1,395,000 scfm

SO2 concentration 740 ppm (O2=6 % dry)

Particulate loading 0.0207 gr/scf (O2=6 % dry)

<Outlet>

SO2 removal efficiency 99 % (on an instantaneous basis)

Particulate loading 0.00236 gr/scf (O2=6 % dry)
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Table 2

Design Basis and Major Equipment of CT-121

Design Condition

<Limestone>

Purity 97 %

Particle Size 90 % passing through 200 mesh screen

<Gypsum>

Purity More than 95 %

Moisture Content Less than 10 %

Major equipment of CT-121

Absorber (JBR) Rectangular type

75.5 ft(W)×75.5 ft(L)×50.2 ft(H)

No. of agitators : 4

Gas to Gas Heater Non-leak type cyclic reheat GGH

Flue Gas Fan Variable pitched axial blade fan

Gypsum Separator Horizontal belt filter

The SO2 removal efficiency of over 99 percent is the most stringent requirement for an IPP

project with a coal-fired boiler in Japan. In addition, the CT-121 must meet other

requirements as well, such as high particulate reduction and producing commercial grade

gypsum.
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Figure 2 shows the results of SO2 removal performance at various boiler loads.

This figure shows superior SO2 removal efficiency of over 99 percent on an instantaneous

basis in the cases of varying load and inlet SO2 concentration.

The CT-121 process is recognized as the pioneer of the limestone forced oxidation (LSFO)

process. The CT-121 process uses a Jet Bubbling Reactor (JBR), which combines SO2

absorption, forced oxidation reaction, neutralization reaction by limestone, and gypsum

crystallization in one process vessel. Since these four reaction steps are performed

simultaneously, the oxidation reaction of absorbed SO2 proceeds very efficiently.

Therefore, stable and higher SO2 removal can be readily achieved due to a lack of any SO2

backpressure in the JBR. This is the reason why the CT-121 can achieve high and stable

SO2 removal efficiency and maintain it under any circumstances.

High SO2 Removal Efficiency with Low Operating Cost

The CT-121 Kobe is designed for higher pH operation compared to the typical operating

pH of other CT-121 installations. Achieving higher SO2 removal efficiency by higher pH

operation leads to the reduction of system pressure drop across the JBR, resulting in

reduction of power consumption of flue gas fan.

The following sections describe the comparison between the CT-121 Kobe and spray tower

processes regarding the additional power consumption required to achieve 99 percent SO2

removal efficiency, as well as the cost reduction by the higher pH operation.

Figure 2: SO2 removal efficiency vs. various boiler loads

90

91

92

93

94

95

96

97

98

99

100

0 12 24 36 48 60 72

 Operating time (h)

SO2 removal efficiency (%)

250

300

350

400

450

500

Inlet SO2 Concentration (ppm)

Efficiency

 Inlet SO2

100% 75% 50% 30%

Load indicating percentage
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Additional power consumption to achieve 99percent from 95 percent

Figure 3 shows the additional power consumption to achieve 99 percent SO2 removal

efficiency compared with 95 percent SO2 removal efficiency in the CT-121 and spray tower

processes.

*1. Power consumption related to SO2 removal efficiency

(CT-121: Flue gas fan and gas cooling pumps, spray tower process: flue gas fan and

recirculating pumps)

*2. Base 100 percent

This figure shows our calculation results of the spray tower’s power consumption. The

calculation base is “New Models for FGD Performance, Cost and Hazardous Sir Pollutant

Removal” 1

 published at the SO2 Control Symposium in 1995.

The figure illustrates that the CT-121 can achieve 99 percent SO2 removal efficiency with

only 26 percent additional power consumption. On the other hand, spray tower processes

need almost 70 percent additional power consumption. This difference exists because the

contact of gas to liquid by the jet bubbling mechanism is more efficient than spray tower

processes.

Moreover, CT-121 Kobe could reduce its operating power consumption by the higher pH

operation. The details are shown in the next section.

Figure 3: Additional power consumption to achieve 99%

as SO2 removal efficiency

169

126

100 *2 100 *2

0

25

50

75

100

125

150

175

200

Spray tower CT-121

Power index (%) *1

95% 99%
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Power reduction by the higher pH operation

Power reduction in the CT-121 Kobe by higher pH operation is shown in Figure 4.

In this Figure, the bar on the left shows the operating power in typical pH operation (Base)

and the bar on the right shows the operating power in the higher pH operation (1.0 higher

than the typical pH) in the CT-121 Kobe.

The CT-121 Kobe has successfully reduced the power consumption of flue gas fan by 16

percent through higher pH operation compared with the typical pH operation.

The operating pH of the CT-121 is usually lower than spray tower processes by

approximately 1.0~1.5. Moreover, the pH of the jet bubbling layer where SO2 is absorbed

is lower than the pH at the pH measuring location. So in that layer, limestone can be

dissolved easily.

From our operating results of the CT-121 in existing installations, we have confirmed that

limestone stoichiometry is only slightly increased even in the higher pH operation. That is

why we applied the higher pH operation in the CT-121 Kobe. As expected, gypsum quality

of higher than 95 percent has been maintained.

Figure 4: Power reduction by higher pH operation

84

50

55

60

65

70

75

80

85

90

95

100

Base Base+1.0

pH (-)

Power reduction index (%)
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High Particulate Removal Efficiency

One of the most important features of the CT-121 is its high particulate removal efficiency,

which is superior to spray tower processes.

Figure 5 shows the particulate removal performance of the CT-121 Kobe.

CT-121 Kobe can maintain stable high particulate removal efficiency at various inlet

particulate loading rates (0~0.04 gr/scf).

This superior particulate removal efficiency is attributed to the efficient contact of gas to

liquid by the jet bubbling mechanism. The particulate loading at FGD outlet is

approximately 0.0005 gr/scf or less, compared with the guaranteed outlet particulate

loading of 0.002 gr/scf.

REDUCTION OF CONSTRUCTION COST AND CONSTRUCTION

WORK PERIOD

In addition to the high performance, the Kobe project emphasized cost reduction, including

minimization of design cost, specification review of the main equipment, and examination

of the installation method. The CT-121 has been improved continuously from the

viewpoint of cost reduction based on the technologies developed by Chiyoda Corporation.

Figure 5: Particulate Loading at FGD inlet vs.

Particulate Loading at FGD outlet

0.000

0.001

0.002

0.003

0.00 0.01 0.02 0.03 0.04

Inlet particulate loading (gr/scf, 6%O2)

Outlet particulate loading

(gr/scf, 6%O2)

Guaranteed zone
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For example, cost reduction was realized by modifying the shape of the absorber as the gas

throughput of the absorber was increased. The cylindrical structure was changed to a

rectangular one, following the structure of the CT-121 for Haramachi Power Plant. Then,

as a result of additional structural analysis, further progress was made in the design

technique. In recent years, the rectangular-shape with combined-panel JBR, which is

directly welded with the reinforcement pillars and beams, has become the standard for

Chiyoda in Japan.

This chapter describes the results of our efforts in reducing the construction work period

and reducing the construction cost for the JBR by making the best use of the advantages of

the combined-panel JBR through effective utilization of heavy construction machines and

cranes.

Reduction of Construction Work Period

The time required for the execution of the Kobe project was approximately three and one

half years in total. This period includes design, manufacturing, construction, and

commissioning. The duration of commissioning phase is not a process requirement, but

contractual requirement. The scope of work includes not only desulfurization equipment

(consisting of absorber, duct, mist eliminator, fan, belt filter, etc.), but also limestone

storage equipment (including limestone powder silo and limestone powder receiving

piping), the gypsum storage equipment (including gypsum silo, gypsum unloading

machine, etc.) and the gypsum shipping equipment (including conveyor belt, ship loader,

etc.). The gross weight of the equipment and apparatus used for this construction was

approximately 4,000 tons. The items in the outline execution period were as follows.

Table 3

Project Execution Schedule

Item 1998 1999 2000 2001 2002

1 Basic Design

2 Detail Design

3 Procurement

4 Shop Fabrication

5 Field Construction

 JBR-Assembly

 JBR-Flake lining

 JBR-Internal work

6 Commissioning

Notes:

• The basic design was started when the kickoff meeting was held with the client.

• The foundation work is not included in the scope of work.

• The commissioning work includes BTG commissioning.
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Table 4 shows the remarkable reduction ratio in the work period of the absorber assembly

compared to the conventional construction of 700 MW FGD with rectangular JBR. The

Table also shows the total manday reduction ratio in the field construction.

Table 4

Comparison of Work Period and Reduction of Construction Mandays

in Absorber Construction

Construction Item Kobe

 Conventional

construction method

for 700 MW

Shell assembly period 70 % 100 %

Flake lining period 80 % 100 %

Internal work period 80 % 100 %

Total construction mandays 85 % 100 %

Note:

• The comparison is made based on actual construction cost data.

The reduction in the work period was achieved for each item and the labor reduction of 30

percent was achieved especially in the panel assembly steps where a new method of

construction was adopted. This was achieved by the following factors:

 Utilization of marine transportation and adoption of the large panel

installation method.

 Increase in the prefabrication ratio.

 Securing the internal work environment by completing the roof panel

installation in the early stage.

Since it was possible to unload items at a quay in the construction site, the side and roof

panels of the absorber were manufactured in a factory and were divided into 15 large parts

(for example, the size of one part was 28.9 ft × 74.5 ft × 3.9 ft, weighing 66,100 lb), thus

increasing the prefabrication ratio considerably. Unloading of the parts was performed

immediately before the side panel installation began without any loss of work period in the

construction steps.

In the conventional method of construction, frame assembly and side panel installation was

repeated step by step. It took about 75 days for the above-mentioned work. On the other

hand, in large-sized panel construction, panel installation was completed for only three

days. It took only 40 days for panel installation including internal beams after the panel

installation was started. After the completion of panel installation, the roof panel was put

into place. In addition, work delays due to bad weather could be avoided by closing the

roof so quickly. This has also contributed to the reduction of construction work period.
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Figure 6 shows the outline of absorber construction sequence of CT-121 Kobe.

Figure 6: Progress of Absorber Construction

Lay down of the bottom plates Installation of the internal beam

Panel Installation

(2 days after the panel installation

started)

Roof Panel Installation

(40 days after the panel installation

started)

Overview of FGD Plant

The work period reduction was achieved compared with the past actual results in the flake

lining and the internal works, which were performed after the shell assembly. The flake

lining work is greatly dependent on the development of application technology. The spray
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method, which is often used overseas, is also established in Japan. The method is expected

to be more effective for larger equipment.

Additionally, the internal JBR decks are made of FRP. Considerable weight savings were

achieved by use of FRP composite material of sandwiched structure. This savings

contributed to the reduction of construction work volume. This FRP composite material

has been used for airplanes and vessels for many years, especially in US and is also used in

the aerospace field in recent years. It will continue to be used in a variety of fields as one

of the state-of-the-art materials.

Reduction of Construction Cost

The following three key goals were set for achieving the reduction of construction cost:

 Material cost reduction.

 Shop fabrication cost reduction.

 Field construction cost reduction.

The comparison of construction cost based on the conventional method of a 700 MW

absorber is shown below.

Table 5

Comparison of Construction Cost for Absorber

Assembly

Item Kobe Conventional

Rectangular Type

Steel weight 86 % 100 %

Shop fabrication cost 71 % 100 %

Field construction

cost

71 % 100 %

Total assembly cost 67 % 100 %

Notes:

• The comparison is made based on actual construction cost data.

• The percentages are shown based on the conventional rectangular

type as 100 percent.

Firstly, as has been previously described, the greatest factor of material cost reduction was

the adoption of the combined shell structure. The design of the combined shell structure

allowed us to replace the separated side panels with the brace of a frame. It enabled the

weight reduction of steel materials because the quantity and size of a frame component

were reduced from the conventional ones, and the main frame could be used both as a beam

and as a stage structure without any modification.

Secondly, as adopting the new construction method for large-size panels increased the

prefabrication ratio, it was expected that the ratio of shop fabrication cost would increase.
14

The overseas fabrication of the JBR was applied for the cost reduction of the shop

fabrication cost due to the lower labor cost. However, risks such as quality deficiency from

quick outsourcing were considered. Therefore, a subcontractor who carried out the design,

fabrication and installation works in Japan for existing CT-121 installations and owns an

overseas factory located in Indonesia、was selected. Cost reduction of 29 percent

compared to the construction of the conventional rectangular type absorber could be

achieved.

Thirdly, the cost reduction of the field construction is discussed hereinafter. The main

factor, which contributed to the field construction cost reduction, was the reduction of work

period. Another factor was the minimization of unnecessary unloading and secondary

drayage by controlling on-site delivery of products using the just-in-time delivery system.

The cost reduction was achieved using all of the above-mentioned three key goals. The

total reduction in the field construction cost reached 29 percent compared to the

conventional rectangular type absorber.

Finally, we conclude this chapter emphasizing that we could achieve an overall cost

reduction of 33 percent in the absorber construction including the flake lining and internal

works compared to the conventional cylindrical type absorber, although our discussion was

limited only to the absorber assembly in this paper.

RELEVANCE OF CT-121 KOBE EXPERIENCE TO NORTH

AMERICAN APPLICATIONS

In North America, Chiyoda Corporation has entered into an exclusive licensing agreement

with Black & Veatch Corporation for the CT-121 FGD process. As utility and industrial

operators face increased requirements for environmental controls, it is expected that the

high SO2 removal capability and the low operating cost of the CT-121 as demonstrated at

Shinko-Kobe Electric Power Plant will allow North American users to achieve their

objectives for environmental compliance while maintaining competitive costs of

generation.

US Environmental Regulations Will Tighten

Three bills were introduced to the 107th Congress proposing major reductions in air

emissions from power generating facilities: Clear Skies Act of 2002, Clean Power Act and

the Clean Air Planning Act. On February 12, 2003, Senator Jeffords re-introduced his

Clean Power Act to Congress, and on February 27, 2003, President Bush's Clear Skies Act

was re-introduced. These legislative proposals would transform the current air quality

regulatory framework from a command-and-control approach to a market based cap-andtrade scheme. Not only would this effect a major overhaul in the regulation of sulfur

dioxide, nitrogen oxide, mercury, and possibly carbon dioxide emissions, but some of these
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legislative bills propose to transform or completely replace several major existing

programs. Meanwhile, a significant and growing number of states have enacted their own,

stringent air emission standards on one or more pollutants.

While these federal legislative proposals are intended to bring more conformity and

certainty to the current situation, it is important to keep in mind that to date, these new

programs are only proposals, and nothing has been passed to negate the current emissions

regulations already in effect. The US Environmental Protection Agency is under court

order to promulgate Maximum Achievable Control Technology (MACT) regulations for no

less than 33 different source categories of hazardous air pollutant emissions in the coming

year, as well as a mercury MACT standard for coal and oil fired boilers by December 2003.

The NOx SIP call is set to begin in May 2004, which will be closely followed by

designation of non-attainment areas under the new ozone and PM2.5 ambient air quality

standards.

Under any new regulations requiring the installation of FGD equipment, cost of compliance

will be a critical issue to be addressed. Moreover, under a cap-and-trade scheme as

contemplated by Clear Skies and the Clean Power Act, the capability to achieve and

maintain greater than 99 percent SO2 removal, as demonstrated by CT-121 Kobe, can

maximize the SO2 reduction at every FGD installation and assist in reducing the overall

cost of compliance.

It is anticipated that emissions reductions resulting from by the Regional Haze Rule and the

PM2.5 National Ambient Air Quality Standard would include additional particulate control

at some facilities. The superior particulate removal performance in the CT-121 could allow

those facilities equipped with the CT-121 for SO2 control to avoid modifications or

upgrades to particulate control equipment.

Fuel Flexibility Enhances Compliance Options

CT-121 Kobe was designed for operation at 99 percent SO2 removal for a one percent

sulfur bituminous coal, analogous to an Eastern US low-sulfur coal. In the US, FGD

installations have been completed for units firing much higher sulfur fuels, as high as

6 lb/MBtu or more. Nonetheless, process design modifications can accommodate high SO2

removal requirements on a variety of fuels, and CT-121 has also been applied for high

removal efficiency requirements on high sulfur applications. At Onahama Smelting and

Refining Company, 99 percent SO2 removal treating a gas stream from a sulfuric acid plant

was guaranteed and achieved with an inlet concentration of 7,000 ppm SO2. In addition, 15

other applications guaranteed and achieve greater than 95 percent SO2 reduction with an

inlet SO2 concentration greater than 2,000 ppm. The fuel flexibility afforded by CT-121

may allow the FGD installation to enhance an overall fuels strategy.

As discussed previously, the efficiency of gas-liquid contact in the CT-121 allows the

process to accommodate increased removal efficiency at a lower incremental power
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consumption compared to conventional spray towers. As a corollary benefit, CT-121 can

achieve and maintain high and stable SO2 removal under varying SO2 inlet conditions.

This results in a reduced operating margin being required to maintain compliance, allowing

greater variations in coal quality while maintaining environmental compliance.

Reducing Construction Cost Risk

Construction costs remain the single greatest risk contributor to cost overruns on FGD

installation projects. Construction costs can escalate tremendously when the available

construction labor resources are exceeded. If environmental retrofit projects proceed as

expected, whether under Clear Skies, mercury MACT, or other programs, construction

labor resources could be constrained. In the US as in Japan, maximum shop fabrication and

assembly is the primary execution strategy to deal with site challenges and project resource

limitations.

Shop labor, combined with shop productivity rates and specialized equipment, produce

work for 35 to 50 percent of the cost for the same activities performed in the field.

Additional costs are incurred for shipping and erection of large components, but the net

savings usually favors maximum shop fabrication. Many US fabricators have their shops

in the Gulf Coast region where barge access permits greater weights (up to 200 tons) and

greater physical dimensions than permitted for truckable modules (limited to 50 tons in

most locations).

In addition to the overall schedule savings afforded by panel construction of the JBR, this

method can allow construction of the absorber module to be taken off the critical path. In

doing so, the required labor resources can be levelized against construction of the new

chimney (if required) or the limestone preparation system. Panel construction of the JBR

can reduce project costs by maximizing shop fabrication, reducing the overall schedule, and

levelizing labor requirements.

CONCLUSIONS

This paper describes our commercial experience of the CT-121 FGD Plant for 700 MW

Shinko-Kobe Electric Power Plant. The operating and construction experiences are

summarized as follows:

 The CT-121 can maintain stable SO2 removal efficiency of over 99 percent on an

instantaneous basis.

 Higher pH operation allowed 99 percent SO2 removal efficiency with only slight

additional power consumption.

 The particulate removal efficiency is superior to that of other spray tower

processes.
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 Applying the panel construction method results in the reduction of construction

cost and reduction of work period.

Application of the CT-121 capabilities and construction cost reduction methods in North

America as demonstrated at Shinko-Kobe Electric Power Plant will allow North American

users to achieve their objectives for environmental compliance while maintaining

competitive costs of generation by:

 Accommodating a wide variety of fuels and inlet conditions.

 Maximizing the results of an investment in FGD technology.

 Avoiding costly particulate control modifications or upgrades.

 Reducing project costs and cost variance through panel construction of the JBR.

ACKNOWLEDGEMENTS

The authors acknowledge the cooperation of Shinko-Kobe Electric Power Plant and Kobe

Steel from the early design stage of CT-121 FGD throughout the construction and

commissioning.

REFERENCES

1. Rubin, E.S. et al, New Models for FGD Performance, Cost and Hazardous Air

Pollutant Removal, 1995 SO2 Control Symposium, FL, 1995

2. Akira Kumagai, et al, Features of the CT-121 System for Operating Cost Reduction,

1999 MEGA Symposium, Atlanta, 1999

KEYWORDS

Black & Veatch

Chiyoda

Construction

CT-121

Flue Gas Desulfurization (FGD)

Kobe

Particulate