H2S removal performance of Ca3Al2O6-stabilized carbide slag from CO2 capture cycles using calcium looping

Abstract

A Ca3Al2O6-stabilized carbide slag from calcium looping cycles for CO2 capture was proposed as a H2S sorbent in zero emission carbon process. The H2S removal performance of Ca3Al2O6-stabilized carbide slag experienced different calcium looping cycles was investigated in a muti-fixed-bed reactor. The fabricated sorbent containing the mass ratio of CaO to Ca3Al2O6 = 73:27 shows higher CO2 capture capacity. The sulfidation temperature and H2S concentration exhibit the important effects on H2S removal by the fabricated sorbent from CO2 capture cycles. The number of CO2 capture cycles has a little effect on H2S removal by the fabricated sorbent. The sulfidation conversions of the fabricated sorbent after 100 CO2 capture cycles at 60 and 120 min can reach 1.3 and 1.6 times as high as those of carbide slag, respectively. Ca3Al2O6 restrains the rapid growth of CaO grains in the fabricated sorbent in CO2 capture cycles. Compared with carbide slag, the fabricated sorbent possesses larger surface area and more stable structure during CO2 capture cycles because of the support of Ca3Al2O6, so it exhibits higher sulfidation conversion. H2S removal using Ca3Al2O6-stabilized carbide slag from calcium looping cycles seems promising in zero emission carbon process.