Capture of CO 2 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

CARBONATOR CALCINER COMBUSTOR Concentrated CO 2 Coal CaCO 3 (F 0 ) CaO Purge CaCO 3 CaO Flue Gas (F CO2 ) Flue gas “without” CO 2 Coal Air O2O2 N2N2 ASU Postcombustion CaO looping Shimizu et al 1999

Calciner CO 2 F CO2 E carb Carbonator F CO 2 CaO CaCO 3 F Ca O F CaO x carb F0F0

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) Gs (kg/m 2 s) Gs (kg/m 2 s) Time (s) Measuring solid circulation rates from P measurements in the carbonator when turning off loop seal

RISER CARBONATOR Loop seal RISER CALCINER Loop seal Valve 2 close Valve 1 close O 2 probe Spyhole Measuring solid circulation rates during solid sampling Valve 1 open Valve 2 open

Overview of 30 kW test rig (2007)

Capture of CO 2 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 CO 2 entering into the carbonator CO 2 leaving the carbonator Carbonation starts Carbonation ends Bed Temperature CO 2 Concentration Bed Temperature CO 2 Concentration Time

Carbonator Temperature = 655 ºC C CO 2 in = 14.0% C CO 2 out = 8.6% Ecarb = 42% ΔP carb = 9 cm carbonator calciner

Gs=0.5 kg/m 2 s Ecarb=21% Ecarb=33% Ecarb=92% Ecarb=15% Ecarb=94% Ecarb=35% carbonator calciner Time (h:min) T4 T5T6T7 T8 Carbonator CO 2 entry

Ecarb=28% Ecarb=82% Time (h:min) carbonator calciner

Gs=0.7 kg/m 2 s Air increase CO2 increase

Capture of CO 2 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 CO 2 F CO2 E carb Carbonator F CO 2 CaO CaCO 3 F Ca O F CaO x carb F0F0 Ideally: F CO2 E carb = F CaO X carb =N CaO r carb

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