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 environmentalCurrently, 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

SteamRegenerator

CoalFoundationFuelHot 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 toby 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 therapid 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 operationcarbonization).

Theresulting

insufficient

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---

11100

SCOPE2140251984

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
100800

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

PowerFuel gas

70600

CDO
recovered271

133

Coke Production cost (%)

Coke oven

CDO
recovered
277

400
600
200

Total
399

460
Total
316

80

Variable
47
Variable
3860

40
Fixed
53200

Fixed
440

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

Reference1) Kunihiko Nishioka et al., Lecture papers at the 12th Coal Utilization Technology Congress, Tokyo, pp.1-2., November 1, 2002.

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