Study on the failure mechanism of potassium-based sorbent for CO 2 capture and the improving measure

Abstract

With thermogravimetric apparatus (TGA), X-ray diffraction (XRD) and barium sulfate gravimetric methods, the carbonation reactivities of K 2CO 3 and K 2CO 3/Al 2O 3 in the simulated flue gases with SO 2 are investigated and the reaction equations are inferred. Results show that there are KHCO 3 and K 2SO 3 generated. The generation K 2SO 3 reduces the utilization ratio of the sorbent. H 2O may accelerates the sulfation reaction of AR K 2CO 3 as K 4H 2(CO 3) 3·1.5H 2O is generated in the reaction among K 2CO 3, SO 2 and H 2O. K 2SO 3 is directly generated from sulfation reaction of K 2CO 3/Al 2O 3, because there are K 2CO 3·1.5H 2O and K 2SO 3 generated in the reaction among K 2CO 3/Al 2O 3, SO 2 and H 2O. K 2CO 3·1.5H 2O does not react with SO 2, and K 2CO 3·1.5H 2O/Al 2O 3 reacts with SO 2 slowly. Compare with the reaction process without H 2O pretreatment, the reaction rates of KAl30 increased after H 2O pretreatment and the failure ratio is about a half of that without H 2O pretreatment. So, K 2CO 3/Al 2O 3 shows good carbonation and anti-sulfation characteristic after H 2O pretreatment.