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Features

Basic Concept or Summary

CDQ - Coke Dry Quenching Process

  Keywords X6 iron & steel Y3 equipment or facility Z4 electricity F26 general machinery

JP Steel Plantech Co.

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Red Hot Coke

Quenched Coke

CDQChamber 

Boiler 

T/G

Steam / Electricity

< Energy Recovery >

Heat

CirculationCooling Gas

◆ Sensible heat of red hot coke (iaround 1,000°C) discharged

from a coke oven is recovered as steam or electric energy.

◆ The treatment by a closed system makes it possible to

prevent atmospheric pollution caused by dust generation and

dispersion that is inevitable when wet quenching is employed.

◆ The quality (strength) of coke is increased due to its

gradual quenching method.

◆ In association with the trend where the size of CDQ is

getting ever larger, the "Double Flue" technology unique to

our company was developed, realizing the increase of 

recovered energy and the stabilization of operation.

◆ CO2 emissions can be reduced, leading to a possibility of employing this process in a CDM project.

◆ Even for a medium to small-scale coke oven, a large-sized CDQ system can be installed without

modifying the existing wet quenching car track. u Sensible heat of red hot coke (iaround 1,000°C)

Single Flue Double Flue

◆ This equipment is composed of a hoisting/charging device for charging the red hot coke in the furnace,

CDQ chamber (preliminary chamber and cooling chamber) for cooling the coke, cut-out device for 

cutting out the coke from the furnace, dust removing device for removing the dust in the circulating gas,

waste heat recovery boiler, and gas blower.

◆ Red hot coke produced by coke ovens is cooled to below

200°C by inactive gas circulating through the CDQ

chamber.

◆ Circulating gas that became high temperature (around

800°C) by heat exchange with red hot coke is introduced

into a waste heat recovery boiler for converting the

sensible heat of the gas to steam.

◆ Circulating gas that became low temperature at the exit of 

the waste heat recovery boiler is pressurized by a blower 

and injected into the furnace through the bottom of theCDQ chamber as cooling gas.

◆ Recovered steam is utilized as process steam or power 

generating steam by a turbine generator.

◆ If the velocity difference of circulating gas becomes too large

in the flue of the CDQ chamber, blow-up of coke might be

induced, leading to the suspension of the operation. By

adopting the "Double Flue" in place of the conventional

"Single Flue," stable operation is

realized. Resultant benefits

include the increase of 

circulating gas volume and

hence, the significant increase of 

the heat efficiency of CDQ.

Dust remover  Boiler Preliminary

chamber 

Coolingchamber 

Cooled coke

Distributor 

Blower 

Dust

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Effects or Remarks

Installation in Practice or Schedule

Domestic ◆ Since 1976, 11 units were delivered (CDQ capacity: 70 - 200 t/h).

◆ Currently, 2 units are under construction (scheduled to start operating in 2009 and 2010).

◆  5 units were delivered to China (CDQ capacity: 140 - 150 t/h).

◆  Currently, 2 units are under construction in China.

◆  Part of the machinery is going to be delivered for 30 units to be fabricated domestically in

China (contract basis).

Overseas

◆ Recovered electric power volume by CDQ

Condition: CDQ operating rate 95% (8,300 h/y)

Coke charging temperature 1,000°C

Explanation: As the circulating gas volume

increases, recovered electric

power increases. A larger CDQprocess tends to cause blow-up,

but this trouble is suppressed by

adopting the "Double Flue."

◆ Difference in recovered electric power volumes

by Double Flue and Single Flue

(The right figure shows the difference in net

volumes of recovered electric power using the

circulating volume of 1200Nm3/t as a base line)

Condition: CDQ capacity 140t/h

  Coke charging temperature 1,000°C

Explanation: By increasing the gas circulating

volume beyond the Single Flue

region (~1200Nm3/t), recovered

electric power can be increased by

around 800kW(4%).

◆ New handling system

As a means to apply a large-sized CDQ

process to a medium to small-scale coke

oven, a new handling system was

developed.

1,200 Nm3/t-coke basis

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CDQ inlet circulating gas volume (Nm3/t-coke)

   D   i   f   f  e  r  e  n  c  e   (   k   W   )

   P  o  w  e  r   G

  e  n  e  r  a   t   i  o  n   (   G   W   h   /  y   )

Coke charged to CDQ (kt/y)

Single Flue region

Advantages1. Transfer necks are eliminated.2. A pseudo quenching car is used, which is applicable in a

wet process as well.

In case of an emergency, wet treatment is possible.

Contact: JP Steel Plantech Co., Global Environment Business Promotion Section

General Manager in charge: Norihiko Inoue. Tel: +81-(0)45-440-5903 Fax: +81-(0)45-440-5841

Manager in charge: Masao Miki, Tel: +81-(0)45-440-5912 Fax: +81-(0)45-440-5841

URL:http://www.steelplantech.co.jp

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