Clean Coal Technologies in Japan

Next-generation, High-efficiency Integrated Coal Gasification Electric

2B5. Power Generating Process (A-IGCC/A-IGFC)
Technology Overview

1. Advanced IGCC/IGFC with exergy recovery technology
The integrated coal gasification combined cycle (IGCC) power

method of energy utilization, the A-IGCC/A-IGFC (Advanced IGCC/IGFC)

generation system under development in Japan provides asystem directs recycled heat from gas turbines or fuel cells back into

generation efficiency of 48% for dry gas cleaning. Also, thesteam reforming gasifiers that employ endothermic reactions. This next-

integrated coal gasification fuel cell combined cycle (IGFC) provides

generation exergy recovery-type IGCC/IGFC being studied. With exergy

55%. These efficiency levels are 7% to 8% lower than that of natural

recovery, the A-IGCC, using 1700oC gas turbines, is expected to provide

gas-fired IGCC/IGFC. An important challenge for Japan is to develop

a generation efficiency of 57% and the A-IGFC, employing fuel cells, istechnologies to more efficiently utilize coal, an energy source that

expected to provide a generation efficiency as high as 65%. Thus, thiscan be stably supplied.

technology is expected to have the potential to bring about a dramaticUnlike the existing IGCC/IGFC system that integrates partial oxidation

increase in system efficiency, contributing, in the future, to the provision

gasifiers, fuel cells, and gas and steam turbines using a cascadeof energy resources and a reduction in CO2 emissions.
65

Existing IGCC/IGFC

A-IGCC/IGFCSystem
combination

Cascade method

Exergy recovery

Gasification

High-temperature partialoxidation (1100 to 1500oC)

Steam reforming(700 to 1000oC)

Gasifiers

Entrained flowMulti-loop high density CFB

Generationefficiency

46 to 48% (55%)

53 to 57% (65%)

Power generation efficiency [%]Table 1 Comparison between existing IGCC and A-IGCC

A-IGFC up to65%

60
55

A-IGCC 1700oC-class
GT 57%

A-IGCC 1500oC-class GT 53%

IGFC 55%
IGCC 1500oC-class
GT wet gas cleaning
IGCC demonstration 46%
unit 1200oC-classIGCC
A-PFBC 1300oC-class GT 46%
GT dry gas cleaning
1500oC-class40.5%
GT dry gas cleaning 48%

504540Year2000

2010
2020
Year of commercialization

2030

Fig. 1 Projection of A-IGCC/IGFC efficiency

2. Overview of A-IGFC
Figure 2 is a schematic drawing of the basic A-IGFC processes. The

approximately 80%. On the other hand, the exergy-recovering IGFC

existing IGFC, which uses energy in a cascade method, integrates

reuses the high-temperature heat generated by the fuel cells in thea gasifier, fuel cells, gas turbines and a steam turbine into agasifier for steam reforming gasification by making use of ancascade-type system. Hydrogen-rich gas produced in the gasifier isendothermic reaction. A-IGFC, using exergy recovery technology,

purified and then sent to the fuel cell unit. Part of the fuel that has

can be expected to substantially improve the generation efficiency.

not been used in the fuel cell unit is transferred to the gas turbines

Recovering waste heat from the fuel cells with low exergy loss andfor power generation. Since this process provides only a low fuelreusing the heat for steam reforming gasification that relies on anutilization rate, the inlet temperature of the gas turbines is aroundendothermic reaction will greatly enhance the cold gas efficiency and1100oC and the power generation efficiency is not more than 55%.

substantially reduce the exergy losses due to combustion.

This is a result of the cold gas efficiency of coal, which is as low as

A-IGFC efficiency: 64.5% (60% plus approximately 5% loss for internal use)
Calculation with SOFC fuel utilization rate of 75% and efficiency of 40%

Ultra-supercriticalpulverized coalunit (USC)

CO2 : 63.5 kg/s, H2: 6.4 kg/s, H2 O: 6.2 kg/s

Fuel cell power
generator

179.9 MJ/s
273.9 MJ/s
1000

1332.2

Gasturbine 147.6
MJ/s
No. 2454.3

103.1
MJ/s

5.55 kPaGas turbine 48
MJ/s
No. 1

Coal: 23kg/s（667MJ/s）
Steam: 53 kg/s
700

Gas turbine
(GT)

USC

ACC
ClosedGTCC

AHAT

Hydrogenturbine

IGCC(O2 injection)

204.3
MJ/s

IGHAT

IGCC/IGHAT(coproduction)

Zero-emission
high-efficiency
power generation

A-IGCCsystem

IGCC(air injection)

Fuel cells
(FC)
13.0
MJ/s

ACC

Gasifier

5 MPa
727.8
20 MPa400
53 kg/s

USC

Coal gasifier

P=1.0 MPa, T=1000

PFBC

IGFC

A-PFBC

A-IGFC

FC
combined

3 MPa
2000

Steam turbine

2010

2020

2030

Fig. 3 High-efficiency power generation technology development

Fig. 2 Schematic drawing of basic A-IGFC processes
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