The negative effects of SO2 on CO2 capture with K2CO3/Al2O3

Abstract

Post-combustion CO 2 capture technology with K-based sorbent is considered to be an innovative capture concept; however, the residual SO 2 in the flue gas will still affect the CO 2 sorption performance of the K-based sorbent. This paper investigated the CO 2 sorption and sulfation characteristics of K 2 CO 3 /Al 2 O 3 . The effects of several variables such as H 2 O concentration, SO 2 concentration, and sorption temperature were studied. Results showed that it was important to investigate the effects of SO 2 on the CO 2 capture capacity of this sorbent, even when the SO 2 concentration is very low due to the fact that the sulfation competes with the CO 2 sorption process. K 2 SO 3 , as the sulfation product, cannot be converted back to K 2 CO 3 for reuse. In order to enhance the CO 2 sorption competitiveness or to increase the reaction rate ratio (e) of the sorbent, the fluidized bed reactor (FBR) was selected as the suitable reactor for the sorption process. Also, besides increasing CO 2 /SO 2 volume ratio in the flue gas, properly increasing the sorption temperature and H 2 O concentration will increase the CO 2 sorption competitiveness. Pretreating sorbent with H 2 O vapor and using them to capture CO 2 in FBR will get further better CO 2 sorption competitiveness. Based on the competition model built in this paper, the activation energy for K 2 CO 3 and SO 2 is 55.01 kJ mol -1 . The results from this study supply theoretical evidence for commercial operation of post-combustion CO 2 capture technology with K-based sorbent.