Download - CDQ Process
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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.
S-4
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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