Part 2 CCT Overview
Multi-purpose Coal Utilization Technologies (Pyrolysis Technologies)

4B1. Multi-purpose Coal Conversion Technology (CPX*)
Research and development: Japan Coal Energy Center; Nippon Steel Engineering Co., Ltd.; JFE Steel Corp.;
Sumitomo Metal Industries, Ltd.; Kobe Steel Ltd.; Ube Industries, Ltd.; Idemitsu Kosan Co., Ltd.;
Nippon Steel Chemical Co., Ltd.
Project type: Subsidized coal production/utilization technology promotion
Period: 1996-2000 (5 years)*Coal Flash Pyrolysis Process: CPX stands for Coal Pyrolysis suffixed with X, indicating diverse products.
Technology overview

1. Technological features
In an attempt to further expand coal’s versatile uses, the aim of

4. Efficient separation of coal ash

this project was to develop multi-purpose coal conversion- Coal ash discharged from gasifier as molten slag and thentechnology with excellent efficiency, economic feasibility, andgranulated with water.

environmental-friendliness, mainly for the purpose of manufacturing

5. Diversified utilization of available products

medium-calorie gas as industrial fuel and liquid products as- Among products, gas can be used as industrial fuel, liquids

feedstocks for chemicals.

(light oil/tar) as feedstocks for chemicals, solid char as fuel or a

The technological objectives were as follows:

reducer, and slag as a raw material for cement.

1. Moderate operational conditions- Heating value of gas produced from the process to approach- A pyrolysis reactor operating at temperatures as low as 600-

approximately 3,500kcal/Nm3.

o950 C.

- Combined yield of gas and liquid (light oil/tar) 70% or more of- A reaction pressure of less than 1Mpa, much lower than several

coal input.

to tens of Mpa used in the coal liquefaction and hydro-gasification

6. Controllable yield of products

processes.

- A change in pyrolysis temperature (600-950oC) or type of coal

2. High overall thermal efficiency

allows product yields to be adjusted accordingly.

- Flash pyrolysis of coal combined with a partial recycling ofgenerated char to gasify more char, thereby improving thermal
efficiency of the process.
3. Multiple varieties of coal
- Utilizing lower grades of coal, from sub-bituminous to highly
volatile bituminous coal, as primary material to enable highgas/tar yields.

Heat recoveryCyclone
Tar cooler
Gas purification

Scrubber
Coal

Pyrolysisreactor

GasCharhopper

Crushing/drying
Char heatrecoverySteamDecanter

Separator

Char gasifier

TarCharSlag
Fig. 1 Process flow diagram
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Clean Coal Technologies in Japan

2. Summary of technology
This conversion process is characterized by higher overall

product (char) separated at the cyclone is recycled to the charthermal efficiency, achieved with a compact, low-pressure

gasifier and the remainder is offered as a product after heatchar/oxygen gasification system that combines the flash pyrolysis

recovery. Heat is recovered from the gas containing pyrolyzedof coal and the partial recycling of pyrolyzed char to use theproducts until it cools down to approximately 350oC through ansensible heat of the char gasification gas as a heat source for theindirect heat exchange with thermal oil while tar passes the

flash heating/pyrolysis reaction of pulverized coal (Fig. 1). The

venture scrubber/tar cooler to be recovered. Pyrolysis gas isentrained-bed coal flash pyrolysis process has been developed tomade available for use as industrial-purpose fuel gas after

not only produce more high-value-added gas and liquid (tar andpurification, such as through light oil (BTX) recovery andoil) with a coke oven gas (COG)-equivalent heating value, butdesulfurization. At the pilot plant (Photo 1), built within the Yawata

also supplies the heat necessary for pyrolysis. Pulverized andWorks of Nippon Steel Corp., tests were conducted mainly with adried coal (of about 50

view to the evaluation/verification of process component/total

m in grain size) is injected into theopyrolysis reactor and mixed with 600-950 C gas and several atm.

system technologies to establish the technological basis for

In a reaction lasting two seconds, the coal is flash

commercialization as well as to obtain data that would aid in theheated/pyrolyzed. Part of the pyrolyzed solid char is recycled todesign of an actual plant (1,000t/d) and to evaluate its economic

the hot gas generation section (char gasifier) to be partially

feasibility. In a period of two years, beginning in 1999, it was test-oxidized by oxygen and steam, thus allowing an approximately

run ten times in all, achieving a maximum 210 hours of stable,o

1,500-1,600 C gas stream, mainly composed of CO and H2, to becontinuous operation. During this period, the aforementioned

generated so that the sensible heat of the gas can be used tofeatures were verified, assuring the controllability of products at

supply heat for the pyrolysis reaction. The pyrolysis reactor

certain pyrolysis temperatures (Fig. 2) prior to completing theemploys an up-flow system where the hot gas generated at thisdata collection process.

gasifier is fed from the lower part of the reactor and, after
pyrolyzed coal is mixed, leaves the system at the reactor’s upper

Pyrolysis product yieldpart together with pyrolyzed products. A portion of the solid

Photo 1 Pilot plantFig. 2 Relationship between pyrolysis product yield and pyrolysis temperature
PDU: 7 ton/day test equipment

References

1) Hiroyuki Kozuru et al., Advanced Clean Coal Technology Int’l Symposium, 2001.
2) Masami Onoda et al., 10th Annual Conference on Clean Coal Technology abstracts, 2000.
3) Shigeru Hashimoto et al., Pittsburgh Coal Conference, 2000.
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