Capture of CO2 from flue gases with CaO. Results in

a 30 kW Interconnected Fluidized Bed Facility

ISCR4, Imperial College. London 2008

• Description of the test facility and the nature of data obtained• A sample of experimental results• Closure of carbon balances

C. Abanades, M. Alonso, N. Rodríguez, B. González, F. Fuentes, G. Grasa, R Murillo

CARBONATORCARBONATOR CALCINERCALCINERCOMBUSTORCOMBUSTOR

Concentrated CO2

CoalCaCO3 (F0)

CaO Purge

CaCO3

CaOFlue Gas(FCO2)

Flue gas“without” CO2

Coal Air

O2

Air

N2

ASU

Postcombustion CaO looping

Shimizu et al 1999

Calciner

CO2FCO2 Ecarb

Carbonator

FCO2

CaO

CaCO3

FCaO

FCaO x carb

F0

Measuring gas concentrations depending on gas split in the loop seal

Air

Split = 1

Air+CO2 Air+fuel

Measuring gas concentrations depending on gas split in the loop seal

Split = 0

Air+CO2

Air

Time (s)

y = 1.0883e-0.0114x

R2 = 0.7222

0

0.2

0.4

0.6

0.8

1

1.2

0 50 100 150 200

Gs

(kg

/m2s

))

Gs (kg/m2s)

y = 2.0415e-0.0216x

R2 = 0.805

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

2.2

0 50 100 150 200 250 300

Tiempo transcurrido (s)

Gs

(kg

/m2s

))

Gs (kg/m2s)

Time (s)

Measuring solid circulation rates from P measurements in the carbonator when turning off loop seal

RIS

ER

CA

RB

ON

AT

OR

Loop seal

RIS

ER

CA

LCIN

ER

Loop seal

Valve 2 close

Valve 1 close Valve 1 close

O2 probe

Spyhole

Measuring solid circulation rates during solid sampling

Valve 1 open

Valve 2 open

Overview of 30 kW test rig (2007)

Capture of CO2 from flue gases with CaO. Results in

a 30 kW Interconnected Fluidized Bed Facility

ISCR4, Imperial College. London 2008

• Description of the test facility and the nature of data obtained• A sample of experimental results• Closure of carbon balances

Example of experimental results with a batch of CaO

0

100

200

300

400

500

600

700

800

900

20:00 20:05 20:10 20:15 20:20 20:25 20:30 20:35 20:40 20:45 20:50 20:55 21:00

Tiempo (h:min)

Tem

per

atu

ra d

el le

cho

(ºC

)

0

5

10

15

20

25

Co

nce

ntr

ació

n d

e C

O2

(% V

ol.)

Temperatura del lecho Concentración de CO2

Inicio de la

carbonatación

Medición CO2 a la entrada del carbonatador

Final de la

carbonatación

Medición CO2 a la salida del carbonatador

0

100

200

300

400

500

600

700

800

900

20:00 20:05 20:10 20:15 20:20 20:25 20:30 20:35 20:40 20:45 20:50 20:55 21:00

Tiempo (h:min)

Tem

per

atu

ra d

el le

cho

(ºC

)

0

5

10

15

20

25

Co

nce

ntr

ació

n d

e C

O2

(% V

ol.)

Temperatura del lecho Concentración de CO2

Inicio de la

carbonatación

Medición CO2 a la entrada del carbonatador

Final de la

carbonatación

Medición CO2 a la salida del carbonatador

CO2 entering intothe carbonator

CO2 leaving the carbonator

Carbonation starts Carbonation

ends

Bed Temperature CO2 Concentration

Bed

Te

mp

era

ture

CO

2 C

once

ntr

atio

n

Time

CarbonatorTemperature = 655 ºC

CCO2 in = 14.0%

CCO2 out = 8.6%

Ecarb = 42%ΔPcarb = 9 cm

carbonator calciner

Gs=0.5 kg/m2s

Ecarb=21%

Ecarb=33%Ecarb=92%

Ecarb=15%

Ecarb=94%

Ecarb=35%

carbonator calciner

Time (h:min)

T4 T5 T6 T7 T8 Carbonator

CO2 entry

Ecarb=28%Ecarb=82%

Time (h:min)

carbonator calciner

Gs=0.7 kg/m2s

Air increaseCO2 increase

Capture of CO2 from flue gases with CaO. Results in

a 30 kW Interconnected Fluidized Bed Facility

ISCR4, Imperial College. London 2008

• Description of the test facility and the nature of data obtained• A sample of experimental results• Closure of carbon balances

Juan Carlos Abanades, Mónica Alonso, Nuria Rodríguez, Belén González, Gemma Grasa,Ramón Murillo, Fernando Fuentes

Calciner

CO2FCO2 Ecarb

Carbonator

FCO2

CaO

CaCO3

FCaO

FCaO x carb

F0

Ideally:

FCO2 Ecarb = FCaO Xcarb=NCaOrcarb

reactor

out 2in 2

ACOCO

Scarb

GPM

X

Carbon balance in the gas and the circulating solids

Conclusions

The 30 kW prototype of INCAR-CSIC has demonstrated the technical viability of the carbonate looping cycles, operating at conditions relatively close to those expected in a flue gas CFB carbonator.

• Modifications (in progress) are necessary in the rig to attain longer periods of stable operation.

•The carbonator reactor works “as expected”. A modeling exercise is required (in progress) for a better interpretation of results and scaling up.

Acknowledgement

This work has been conducted under a contract Hunosa-CSIC