Advanced Coal Gasification Technology based on Exergy Recuperation

The University of TokyoInstitute of Industrial and Science

Collaborative Research Center for Energy Engineering

Atsushi Tsutsumi

Hybrid Gasification of coal, biomass, waste plastics,

FCV

Syn gas（H2、CO）

oil

ST

GT boiler

FC

gasification

　biomass

coal

waste

gasifier

SteelＨ２ＣＯ２slug

Effectiveuse

Electric power

Japan’s New Coal Policy C3 Initiative towards the establishment of the Clean Coal Cycle

Chemicals

Iron and steelReduced ore

commercial, transportation

Power plants, Automobiles, etc.

METI C3 Initiative

Demonstration of diversified CCT models, with coal gasification as the core technology

Co-production of chemicals

Co-production of Steel iron

IGCC／IGFC

ＤＭＥ、ＧＴＬ

Storage

Hydrogen Station

Stationary FC

Ｈ２ ProductionCO2 sequestration

Blast furnace

Diesel, naphthalene, etc.

Methanol, acetic acid, etc.

High-efficiency power generation technology development

2000 2010 2020 2030

USC

GT ACC(1500°C)

ACC(1700°C)

USC(700°C)

USC(800°C)

AHAT

IGCC(O2 blow)

A-IGCC

IGFCA-PFBC

IGHAT IGCC/IGHAT(coproduction)

gasifier

FCcombined

IGCC(air blow)

fuel cell

hydrogencombustion turbine

closedGTCC

PFBCA-IGFC

Sustainable Clean Coal Technology

・biomass, waste, plastics, heavy oil, etc.

・low rank coal

Diversification of energy resources

・exergy recuperative gasification・partial oxidation gasification at high temperature -> steam gasification at low temperature

・SOx, NOx, PM, heavy metals

・CO2 sequestration ready

・hydrogen co-production

More Efficient Utilization of Coal

Hybrid Gasification

Zero-Emission

Partial oxidation Low cold gas efficiency Recycle of waste heat from GT/FCLarge cold gas efficiencyReduction of exergy loss

gasifier fuel cell GT STcoal

waste heat

gasifier GT STcoal

waste heat

gasifier fuel cell GT STcoal

gasifier GT STcoal

combustion

combustion

Integration Technology: Energy Cascading & Exergy Recuperation

Cascade utilization (IGCC/IGFC) Exergy recuperation (A-IGCC/IGFC)

Combustion Exergy Recuperation

The recuperation of low-level heat can minimize the energy loss in the energy conversion process

10095

10070

Thermal  Energy

Chemical  EnergyExergy loss

25 10095

135109

3514

Thermal  Energy

Chemical  Energy

Hydrogen  

Energy

13595

Thermal  Energy

Exergy loss14

H2O

Fuel

H2

500-1100 K

2000 K

combustion

reforming reaction

Thermochemical cycle for hydrogen production as a thermochemical heat pump

Energy flow in the cascade utilization IGCC system

Cold gas efficiency 80%

�

η = 28 + 25100

= 53% (48%)

�

η = 47 + 12100

= 59% (57%)

�

η = 32 + 16 + 12100

= 60% (55%)

exhaust loss

condenserloss

10095 168

136

6841

2929

4141

66

4427

2414

8355

126

120

186

gasifier FC ST

power

power GT

powerexergy rate100

0

50

�

η = 41+ 29 + 6100

= 76% (70%)

A-IGCCIGCC

A-IGFCIGFC

Comparison between conventional and advanced IGCC/IGFC

Conventional IGCC/IGFC A-IGCC/IGFC

integration cascade utilization exergy recuperation

gasificationpartial oxidationhigh temperature(1100-1500°C)

steam reforminglow temperature

(700-1000°C)

gasifier Entrained flow bed high density CFB

efficiency 46−48% (IGCC) ～ 55% (IGFC)

53−57% (A-IGCC) ～ 65% (A-IGFC)

65

60

55

50

45

40

2000 2010 2020 2030

Year

A-IGCC1500°C GT53%

A-IGCC1700°C GT57%

A-IGFC～65%

IGFC55%

IGCC1500°C GT

dry gas cleaning48%

IGCC1500°C GT

wet gas cleaning46%IGCC

1200°C GTdry gas cleaning

40.5%

A-PFBC1300°C GT46%

Projection of improvement of generation efficiency

O2 Steam

CO, CO2

Combustor

GasifierCO,H2

Coal

Tar/gases

Pyrolyzer

Char

Heat carriedparticles

Char+particles

Heat carried particlesPyrolyzer（Downer reactor）

CoalGases (CO, H2, CH4 etc.)+Tar

Char

Gasifier（Bubble fluidized bed）

Char

+Steam

CO、H2

Unreacted Char

Combustor（Riser reactor）

Unreacted Char

+O2CO, CO2

ParticlesHea

t

In order to use the heat effectively, circulating a large amount of particles in this system is required !!!

Illustrated by Dr Mastuoka, AIST, Japan

Heat

A novel high-density triple-bed CFB (TBCFB) gasifier

Riser: Ф0.1mX16.6mDowner: Ф 0.1mX6mBFB: 0.75m X 0.27m X 3.4m

A novel large-scale TBCFB system

Exergy Recuperation Technology

Efficient Combustion Energy Cascading

熱エネルギー

Self-heat RecuperationSupercombustion

waste heatThermal  energy(high  Temp.)

Thermal  energy(low  Temp.)Chemical  Energy Thermal  Energy

Energy Cascading Self-heat RecuperationHeat Utilization

Heat Circulation by self-heat recuperation can reduce the energy requirement in the process drastically

Y. Kansha, N. Tsuru, K. Sato, C. Fushimi, A. Tsutsumi, Industrial and Engineering Chemistry Research 48(16), 7682-7686, 2009

T0

Tb’

T1

Feed

Effluent

Tb

Qheat exchange

Q

T

Q

T

T0

Tb

T1

Feed

Effluent

Qheat exchange

Self heat Exchange Self-Heat Recuperation

Energy Saving Energy Saving

Distillation based on Self-heat Recuperation

!

"!!

#!!!

#"!!

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7561&6/06.4*203/044./056

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preheater

distillation column

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F

Enthalpy

Tem

pera

ture

RB

CD

QRB QCD

F

Heat supplied by reboiler is wasted in the condencer

Self heat is recuperated by adiabatic compression

Energy consumption Energy saving

80～90% reduction

Energy consumption

85% reduction in energy consumption by self-heat recuperation

The heat of condensation is recuperated by compressors and exchanged with the heat of vaporization.

Self-recuperative CO2 Separation

CO2

Reboiler

Condencer

Flue  gas

Exhaust  gas

StrippingAbsorption

50°C120°C

In the chemical absorption process (MEA), the process energy is needed 4.1GJ/t-CO2.68% energy saving can be achieved by self-heat recuperation

Self-heat recuperative Drying

MVR SHR

Comparison of required energy input Comparison of exhausted CO2

Conduction drying

Hot air drying

MVR SHR

Heat recovery

No heat recovery

Heat recovery

No heat recovery

Conduction drying

Hot air drying

LHV(EHV)

HHV

Water evap. heat

Self combustion

Combustion gas (900ºC)

Moisture content [ wt% wb]

Hea

t am

ount

[ M

J/kg

]High energy demand for drying because of large latent heat of water evaporation

Sustainable Clean Coal Technology

• The hydrogen and power co-production by using the exergy recuperation gasification technology could considerably increase the energy utilization efficiency

Exergy Recuperative Gasification

Exergy Recuperative Drying

Exergy Recuperative CCS

Exergy Recuperative Gas Cleaning

• The self-heat recuperative drying which recovers not only latent heat, but also sensible heat can save drying energy. • This is a key technology for the improvement of power generation

efficiency in the utilization of brown coal and/or biomass with high moisture content.

• The energy for the CO2 separation and gas cleaning can be reduced by over 70%.