Study on the failure mechanism of potassium-based sorbent for CO2 capture and the improving measure

With thermogravimetric apparatus (TGA), X-ray diffraction (XRD) and barium sulfate gravimetric methods, the carbonation reactivities of K2CO3 and K2CO3/Al2O3 in the simulated flue gases with SO2 are investigated and the reaction equations are inferred. Results show that there are KHCO3 and K2SO3 generated. The generation K2SO3 reduces the utilization ratio of the sorbent. H2O may accelerates the sulfation reaction of AR K2CO3 as K4H2(CO3)(3)center dot 1.5H(2)O is generated in the reaction among K2CO3, SO2 and H2O center dot K2SO3 is directly generated from sulfation reaction of K2CO3/Al2O3, because there are K2CO3 center dot 1.5H(2)O and K2SO3 generated in the reaction among K2CO3/Al2O3, SO2 and H2O center dot K2CO3 center dot 1.5H(2)O does not react with SO2, and K2CO3 center dot 1.5H(2)O/Al2O3 reacts with SO2 slowly. Compare with the reaction process without H2O pretreatment, the reaction rates of KAl30 increased after H2O pretreatment and the failure ratio is about a half of that without H2O pretreatment. So, K2CO3/Al2O3 shows good carbonation and anti-sulfation characteristic after H2O pretreatment. (C) 2011 Elsevier Ltd. All rights reserved.