Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

Petersenstrasse 3064287 Darmstadt / GermanyPhone: +49 6151 16 2191www.est.tu-darmstadt.de

Carbonate looping experiments in 1 MWth scale using a CFB calciner fired with coal and oxygen-enriched air

Jochen Ströhle

2nd International Workshop onOxyfuel FBC Technology28-29 June 2012 at University of Stuttgart

Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

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Outline

Carbonate looping process

1 MWth pilot plant at TU Darmstadt

Results of experiments with propane-fired calciner

with coal-fired calciner

Conclusions

Further work

Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

Carbonate Looping Process

Retrofit of existing power plants is feasible. Repowering: Electrical power of total plant increases by ~80 %. Steam parameters of 600 / 620 °C in the CL unit are feasible Efficiency decreases by < 3 % units (without CO2 compression) CO2 capture of ~88 % CO2 avoidance costs of ~20 €/t CO2

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Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

Sketch of a Carbonate Looping Unit

Carbonate looping unit of 1050 MWel hard coal fired plant One of two parallel flue

gas cleaning trains

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Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

Scheme of 1 MWth CL Pilot Plant

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Filter Cyc

lone

Cal

cine

r, 90

0 °C

CFB

600

Coa

l Com

bust

or

HeatExchanger

Sta

ck

Car

bona

tor,

650°

CFan

Fan

Induced Draft Fan

Fan

Coal

Ash

Flue Gas

Decarbonized Flue Gas

Fly Ash

CaCO3

CaO

Option: Air

Ash

CO

2

N2

OptionC

yclo

ne

CaCO3(Makeup)

Coal

CFB

400

CO

2

O2

Filter

FGD

HeatExchanger

Sta

ck

Induced Draft Fan

CO2

Fly Ash

Filter

Preheating Preheating

Steam

Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

3D View of Laboratory

Erected in 2009 20 m high

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Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

Layout of Coupled CFB Reactors

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CarbonatorCFB600

CalcinerCFB400

Inner diameter 0.6 m 0.4 mOuter diameter 1.3 m 1.0 mHeight 8.66 m 11.35 mCal

cine

r

Car

bona

tor

Calciner

Carbonator

Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

CL Experiments in 1 MWth Plant

July 2011: CO2 capture with propane-fired calciner 5 weeks of 3 shift operation 72 hours of continuous CO2 Capture, Calciner fired with propane

Jan 2012: CO2 capture with coal/propane-fired calciner (Campaign Propane) 19 days of 3 shift operation 121 hours of CO2 capture Calciner mainly propane-fired

Feb 2012: CO2 capture with coal-fired calciner (Campaign Coal) 5 days of 3 shift operation 30 hours of CO2 capture El Cerrejón coal

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Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

Experimental Setup Jan/Feb 2012

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Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

Campaign Propane

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CO2 absorption: 60 – 88 %Gas velocity: 2.3 – 3.3 m/sAverage makeup: 59 kg/h (CaCO3)Particle size: 100 – 300 µm

Gas velocity: 3 – 4 m/sPower: 420 – 500 kWthO2 in: 35 – 40 % vol.

56 % vol. O2

Air

Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

Campaign Propane

Period of 12 hours stable operation

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CO2 absorptioncarbonator

CO2 capture total

Carbonator Calciner

O2 in

CO2 out

Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

Campaign Coal

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CO2 absorption: 58 – 88 %Gas velocity: 2.3 – 2.6 m/sAverage makeup: 8 kg/h (CaCO3)Particle size: 100 – 300 µm

Gas vel.: 3.2 – 3.8 m/sPower: 550 – 800 kWthO2 in: 43 – 50 % vol.

51-57 % vol. O2

Air

Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

Campaign Coal

Period of 20 hours stable operation

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Carbonator Calciner

CO2 absorption carbonator

CO2 capture total O2 in

CO2 out

Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

Effect of CO2 equilibrium and chemical kinetics in carbonator

Campaign Coal

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equilibrium CO2 conc.

CO2 conc. at exit

Start CO2

1 2 3 4 1. no CO2 addition

2. CO2 absorption limited by equilibrium

3. CO2 absorption limited by kinetics (~640 °C)

4. CO2 absorption limited by kinetics (~610 °C)

Start cooling

Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

Operation of Carbonator

a) CO2 absorption limited by equilibrium: Temperature increases CO2 equilibrium concentration increases CO2 absorption decreases Temperature decreases Stable operation

b) CO2 absorption limited by chemical kinetics: Temperature increases CO2 absorption increases Temperature increases further CO2 absorption finally limited by equilibrium or availability of CaO Unstable operation

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2,1.432 1011 19130

E.H. Baker, J. Chemical Society, 1962

Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

Conclusions

1 MWth CL pilot plant in continuous operation

>200 hours of CO2 capture

Propane-/Coal-fired calciner

~50 % vol. O2 enrichment in calciner

>80 % CO2 absorption in the carbonator

>90 % total CO2 capture (carbonate + oxyfuel fired calciner)

CO2 absorption in carbonator strongly dependent on temperature either limited by equilibrium (stable operation) or by chemical kinetics (unstable operation)

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Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

Further Work

Test with real flue gas from coal-fired furnace (1 MWth)

Test at real oxyfuel conditions in calciner (O2/CO2/steam mixture)

Optimization of operating conditions

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Swirl burner

Water-cooled membrane walls

Water-cooled tube bundles

Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

Acknowledgements

COORETEC Project “LISA” - Limestone based Absorption of CO2

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Energy Systemsand TechnologyProf. Dr.-Ing. B. Epple

Announcement

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2nd International Conference on Chemical Looping

26 to 28 September 2012at TU Darmstadt

Thank you for your attention