OXYCOAL-AC

1

OXYCOAL-AC: Component Behaviour

and Thermodynamic Efficiency

H. Stadler, F. Beggel, B. Persigehl,R. Kneer, M. Modigell, P. Jeschke

RWTH Aachen University, Germany

Fourth International Conference on Clean Coal Technologies,Dresden, Germany, 18-21 May 2009

OXYCOAL-AC

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OXYCOAL-AC Project

Potential for DevelopmentSensitivity Analysis

Thermodynamic Integration

AirN2

O2

Primary Air

ID FanCO2

G

M/G

AirN2

O2

Primary Air

ID FanCO2

GG

M/G

Overview

OXYCOAL-AC

3

Partners at

Goal:

Development of a Pulverised Coal Oxyfuel Power Plant Based on Oxygen Transport Membranes

Topics:

Coal Combustion in CO2

/O2

-Atmosphere

High Temperature Membrane for Oxygen

Supply

Funded by:

Institute of Heat and Mass TransferInstitute of Automatic Control

Institute of Jet Propulsion and Turbomachinery

Institute of Combustion Technology

Dept. of Chemical Engineering

Institute for Materials Application in Mech. Eng.

Project

OXYCOAL-AC

4

Coal

Water

Steam

Conventional Steam Generator

Flue Gas (N2

+ CO2

+ H2

O)

Air

OXYCOAL-AC

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Water

Steam

O2

+ CO2

+ (H2

O)

Oxyfuel Process

Flue Gas (CO2

+ H2

O)

Oxygen

Cryogenic Air Separation Unit or Oxygen Transport Membrane (OTM)

Coal

OXYCOAL-AC

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Air

N2Recirculation Fan

Water

Steam

O2

OTM

Turbo-

unit

Three-End Integration

Flue Gas (CO2

+ H2

O)

O2

+ CO2

+ (H2

O)

Coal

Vacuum Pump

OXYCOAL-AC

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Air

N2

O2

Hot Gas Filtration

Ash

O2

+ CO2

+ H2

O

Four-End Integration

Flue Gas (CO2

+ H2

O)

Water

Steam

OTM

Coal

Turbo-

unit

OXYCOAL-AC

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O2

Hot Gas Filtration

Ash

Membrane Parameters

Flue Gas (CO2

+ H2

O)

Water

Steam

OTM

Coal

Air

N2

Turbo-

unit

Membrane Parameters

Temperature: 825 °C

Mean Pressure Ratio: 20

Mean Partial Pressure Ratio: 26

Oxygen Separation Degree: 90 % (O2

in depleted air: 2.5 vol.-%)

O2

+ CO2

+ H2

O

Flue Gas (CO2

+ H2

O)

OXYCOAL-AC

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Base Process

AirN2

O2 ID FanCO2

G

M/G

HGF

Membrane

Recirculation Fan

OXYCOAL-AC

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AirN2

O2 ID FanCO2

G

M/G

HGF

Membrane

Recirculation Fan

Water-Steam Cycle

Parameters according to RPP NRW

600/620 °C

285/60 bar

45 mbar

Number and Position of Preheaters

Thermal Load: 1210 MW

Low Pressure Preheaters

High Pressure Preheaters

Condenser

Economiser

OXYCOAL-AC

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AirN2

O2 ID FanCO2

G

M/G

HGF

Membrane

Recirculation Fan

Membrane Integration850 °C

400 °C

OXYCOAL-AC

12

AirN2

O2 ID FanCO2

G

M/G

HGF

Membrane

Recirculation Fan

Membrane Integration II

750 °C

OXYCOAL-AC

13

AirN2

O2 ID FanCO2

G

M/G

HGF

Membrane

Recirculation Fan

Full Integration

Economiser

120 …

135 kWh/tCO2

OXYCOAL-AC

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AirN2

O2 ID FanCO2

G

M/G

HGF

Membrane

Recirculation Fan

Low Pressure Preheaters

Economiser

η

= 39.3 %

OXYCOAL-AC

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AirN2

O2 ID FanCO2

G

M/G

HGF

Membrane

Recirculation Fan

Auxiliary Power Demand I

Economiser

46 MW

195 MW-217 MW

-585 MWel

-22 MWel

48 MW

OXYCOAL-AC

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CO2

Compressionch

ange

in e

ffici

ency

air leakage

0 %1 2 3

-0.25

0

%

-0.5

0.25

OXYCOAL-AC

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Recirculation Fanenergy demand is determined by:

■

recirculated mass ( O2 concentration)

■

inlet temperature of recirculation fan

OXYCOAL-AC

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Recirculation Fanenergy demand is determined by:

■

recirculated mass ( O2 concentration)

•

partial pressure ratio

•

separation degree

•

total pressure ratio

■

inlet temperature of recirculation fan

OXYCOAL-AC

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Partial Pressure Ratio

membrane area

chan

ge in

effi

cien

cy

partial pressure ratio

15 -20 25 30

0

0.5

%

-0.5

1.0

OXYCOAL-AC

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Separation Degree

limit of temperature difference in heat exchanger

chan

ge in

effi

cien

cy

0

0.5

%

-0.5

1.0

oxygen separation degree

80 %85 90 92.582.5 87.5

AirN2

O2

M/G

Membrane

OXYCOAL-AC

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Total Pressure Ratioch

ange

in e

ffici

ency

total pressure ratio

15 -20 25 30

-0.5

0

%

-1.0

0.5

OXYCOAL-AC

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Recirculation Fanenergy demand is determined by:

■

recirculated mass ( O2 concentration)

•

partial pressure ratio

•

separation degree

•

total pressure ratio

■

inlet temperature of recirculation fan

•

level of integration

OXYCOAL-AC

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Base Process

AirN2

O2 ID FanCO2

G

M/G

HGF

Membrane

Recirculation Fan

OXYCOAL-AC

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AirN2

O2 ID FanCO2

G

M/G

HGF

Membrane

Recirculation Fan

Intermediate Level Integration

Economiser

η

= 39.9 %

OXYCOAL-AC

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AirN2

O2 ID FanCO2

G

M/G

HGF

Membrane

Recirculation Fan

High Level Integration

Economiser

η

= 40.1 %

OXYCOAL-AC

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Potential for Development■

Driving turbine for recirculation fan ( + 0.1 %-pt)

■

Inlet evaporative fogging at air compressor (+ 0.5 %-pt)

■

Increase of nitrogen turbine inlet temperature

OXYCOAL-AC

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Air

O2 ID FanCO2

G

M/G

HGF

Membrane

Recirculation Fan

Co-Firing

Flue

Gas

η

= 46.1 %

OXYCOAL-AC

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Comparison

Efficiency incl. CO2

-

Compression

Efficiency without CO2

-

Compression

CO2

-Emission [gCO2

/kWhel

]

Cost for O2

-

Production [kWhel

/tO2

]

RPP-NRW 45.9 750

Low Integration 39.3 43.2 87 94

Intermediate Integration 39.9 43.8 86 75

High Integration 40.1 44.0 85 66

Optimisation of Membrane Parameters 40.7 44.6 84 46

All Features 41.4 45.3 83 21

Co-firing 46.1 49.1 161 -

OXYCOAL-AC

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Thank You very much!

OXYCOAL-AC

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Backup

OXYCOAL-AC

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Auxiliary Power Demand II

Water Pumps (16 %)ID Fan (1 %)

CO2

Compression (36 %)Recirculation Fan (35 %)

Primary Air Fan (3 %)

Others (8 %)

HGF (1 %)

OXYCOAL-AC

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AirN2

O2 ID FanCO2

G

M/G

HGF

Membrane

Recirculation Fan

High Pressure Preheater

Economiser