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 isCDQ
chamberscollected through a pipe located in the upper section of theFeedwatercarbonization 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/hrCapacityCompanyWorks

Targetfurnaces

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

PlantsPressure(kg/cm2)

Nippon SteelOita

No. 1, 2

190 (1)

112.0

95520

Oct. 1988

Oita

No. 3, 4

180 (1)

92.5

93520

Aug. 1985

YahataNo. 4, 5

175 (1)

120.0

75495

Feb. 1987

106 (1)

65.0

117

525

Sept. 1985

oCoke charge temperature

1000-1050 C

Coke output temperature

200oC

Temperature(oC)

Put intoservice

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. 4129 (1)71.4117525

Feb. 1982

Steam temperature

440oC

KimizuNo. 1, 2, 3

110 (3)

60.0

95520

Oct. 1982, Aug. 1983

Total gas volume

84,000Nm3/hr

KimizuNo. 4, 5

170 (1)

108.0

95520

Jan. 1988

Hokkai Steel

Muroran

No. 5, 6

108 (1)

56.5

64490

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

20280

Sept. 1976

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

No. 6, 7

Water content (%)

2-50.1-0.3

East Japan No. 1

Ash content (%)

11.35

11.39(Keihin)

Volatile components (%)
Average particle size (mm)0.50
650.4155

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

1013Porosity (%)

4948

DI 15 (%)

83.5

85.5

DI 15 (%)

150

12.9

17.9

Coke strength after small reaction (%)

50

52150

Sumitomo Metal
Industries

Composition of circulating gas
Gas

CO2CO

H2

N2

Concentration (%) 10-15

8-10

2-3

70-75

Kansai Cokeand Chemicals
Nakayama Steel Works

5170 (3)

39.0

20280

Jul. 1979

West Japan No. 3, 4100 (2)64.999.0330

Aug. to Sep. 1983

(Kurashiki) No. 5, 6130 (1)

85.0

99.0

330

Jan. 1986

West Japan No. 4125 (1)69.0105540

Apr. 1986(Fukuyama) No. 5200 (1)

116.5

85520

Feb. 1990

No. 3

185 (1)

111.7

86523

Jan. 1997

195 (1)100.0

105.0545

Mar. 1986

No. 2AB150 (1)65.0

105.0545

Jan. 1984

No. 2

Kagoshima No. 1ABCD

No. 2CD

130 (1)

65.0

105.0

545

Nov. 1981

Wakayama

No. 6100 (1)60.0102540

Apr. 1994

Kakogawa

No. 1, 2

140 (1)84.0

112.0556

Jun. 1987

No. 3, 4150 (1)98.0

112.0556

Oct. 1998

No. 258 (1)31.065490

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

CDQsystem

the 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.

CraneCharger
Power plants

Primary dust catcher
Pre-chamber

Steel works
Boiler

Cooling chamber

Chemical plants

Water pre-heater
BucketEjector
Secondary dust catcher
Gas recirculating fanBelt conveyorCDQ 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-friendlytechnology.

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.
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