Multiple-Cycles Behavior of K₂CO₃/Al₂O₃ for CO₂ Capture in a Fluidized-Bed Reactor

Abstract

The sorbent of K 2 CO 3 /Al 2 O 3 is a good choice for CO 2 capture from flue gas of fossil-fuel-fired power plants. The CO 2 -capture capacity and regeneration property for K 2 CO 3 /Al 2 O 3 were investigated in a bubbling fluidized-bed reactor during multiple cycles. Results show that the carbonation conversion for K 2 CO 3 /Al 2 O 3 is greater than 90% during 10 cycles. The microstructure character of K 2 CO 3 /Al 2 O 3 is stable. The changes of surface area and pore volume are 8.3 m 2 /g and 0.036 cm 3 /g, respectively, after 10 cycles, and there is little change in the pore size distribution. Careful temperature control is important because of the narrow temperature window available for CO 2 capture and the highly exothermic nature of the carbonation process. After 10 cycles, the elutriated sorbent is only 2.8 wt % and the reducing rate of average particle size is 0.005 mm/h. The sorbent of K 2 CO 3 /Al 2 O 3 shows excellent attrition resistance performance.