Part 2 CCT Overview
Coal-fired Power Generation Technologies (Gasification Technologies)

Coal Gasification Fuel Cell Combined Cycle Electric
2B4. Integrated
Power Generating Technology (IGFC)
Technology Overview

1. IGFC process flow
The integrated coal gasification fuel cell combined cycle (IGFC)

reduce CO2 emissions by approximately 30% from the level ofgasifies coal for use in triple combined power generation, which

existing pulverized coal-fired power generation systems. IGFC iscombines three different types of generation systems: fuel cells,

expected to become a coal-fired power generation technology ofgas turbines and steam turbines. This high-efficiency power

the future, although there are still many challenges to be overcome

generation technology is expected to provide power generation

for commercialization, including the development of inexpensive

efficiency of 55% or higher, if successfully developed, and tohigh-efficiency fuel cells (Fig. 1).

Coal

Power generation efficiency: 55%

Coal gasifier

CO2 emission reduction: 30%

Desulfurizer

Gypsum collector
Scrubber
Syngas cooler
Regenerator
GGH

GypsumCOS converter

FilterACDCFC
Slag

Wastewater treatment system

HRSG

Combustion turbine

RectifierStackCondenser
Steam turbine

Fig. 1 IGFC process flowchart

2. Types and features of fuel cells
Fuel cells employ the electrochemical reaction between hydrogen

phosphoric acid fuel cells (PAFC), molten carbonate fuel cells

and oxygen to directly generate power. With their high-efficiency(MCFC), solid oxide fuel cells (SOFC), and solid polymer electrolyte

and excellent environmental features, fuel cells are now in thefuel cells (PEFC).

limelight. They can be classified by electrolyte material intoType

Phosphoric acid (PAFC)

Electrolyte

Phosphoric acid aqueous solution Li/Na carbonate

Ionic conductor

H+Molten carbonate (MCFC)

CO3

Solid polymer electrolyte (PEFC)

Stabilized zirconia

Solid polymer membrane

2-H+OApprox. 650 to 700 C

900 to 1000 C

70 to 90oC

Generation efficiency (HHV) 35% to 42%

45% to 60%

45% to 65%

30% to 40%

Raw materials and fuels

Natural gas, methanol, naphtha

Natural gas, methanol, naphtha, coal

Natural gas, methanol, naphtha, coal Natural gas, methanol, naphtha

Application

Co-generation anddistributed generation

Co-generation and distributedgeneration, substitute for thermal
power generation

Co-generation and distributedgeneration, substitute for thermal
power generation

Operating temperature

o2-Solid oxide (SOFC)

Approx. 200 C

ooCo-generation and portable
power supply, automobiles

Among the fuel cells above, MCFC and SOFC operate at highheat and converts the heat into electrical energy. Unlike thistemperatures and are expected to be highly-efficient technologies

system, fuel cells derive electrical energy directly with lower

for next-generation large-scale power plants due to the followingenergy losses and higher generation efficiency.

features: (1) they can be used in combination with gas turbines,

SOFC, consisting of ion-conducting ceramics, generate heat atand (2) they can accept coal gas.

temperatures as high as 900oC to 1,000oC during the chemical

SOFC produce power through an electrochemical reaction

reaction. Combined with gas turbine generation, SOFC canbetween hydrogen, which has been derived from gasified fuel, andprovide higher generation efficiency than other types of fuel cells.

oxygen in the air. This mechanism is the reverse process of theBesides coal-gasified gas, LNG, methanol or biogas can also beelectrolysis of water.

used as fuel.

The traditional power generation system burns fuel to generate
41