Thesis (Ph.D.)--Chulalongkorn University, 2011

The purpose of this study is to investigate the effect of flow pattern/regime in fluidized bed/circulating fluidized bed on CO2 capture from flue gas, released from a fossil fuel combustion process, at low temperature 60 ℃ using potassium carbonate supported on alumina (K2CO3/Al2O3) solid sorbent prepared by impregnation method. The semi-circulating fluidized riser made from glass has 0.025 m of inner diameter and 0.80 m of height. The flow pattern/regime was characterized by measuring pressure fluctuation in the riser. It can be divided into five different flow patterns/regimes including fixed bed, multiple bubbling, slugging, turbulent and fast fluidization as gas velocity increased. The fixed bed and multiple-bubbling bed could adsorb all CO2 in flue gas (CO2 removal fraction = 1). The slugging, turbulent and fast fluidization could not remove all CO2 in flue gas. Maximum CO2 removal fractions for slugging, turbulent and fast fluidization are 0.98, 0.94 and 0.72, respectively. However, the turbulent regime provides the best CO2 capture capacity at about 90% of stoichiometic theoretical value. The CO2 capture capacity for the multiple-bubbling and fast fluidization regimes are secondary with about 66-72% of stoichiometic theoretical value. The fixed bed and slugging regimes provide the poorest CO2 capture capacity at about 53-60% of stoichiometic theoretical value. For K2CO3/Al2O3 solid sorbent, this solid sorbent was completely regenerated for temperature higher than 300 ℃ resulting in higher stability to maintain capacity.