Kinetics of desulfurization of hot fuel gas with calcium oxide. Reaction between carbonyl sulfide and calcium oxide

Abstract

The reaction between carbonyl sulfide and calcium oxide was studied since the typical concentration of COS is 0.01Vertical Bar3< in the fuel gases from commercially available coal gasifiers. Rates of sorption of 0.1Vertical Bar3< COS in N/sub 2/, with 10Vertical Bar3< CO added to suppress decomposition of COS, were measured at 500/sup 0/-900/sup 0/C, a total pressure of 1 atm and a flow rate of 2000 std cc/min. The CaO sample was a reagent-grade fine powder with a particle size of 1-5 jm. The over-all rates at 600/sup 0/-900/sup 0/C correlated satisfactorily with the grain model (with a shape factor of 1.5), where chemical reaction was the rate-limiting step. The rate of reaction of COS with CaO was first order in COS with an activation energy of 4.3 kcal. The rate of sorption of COS by CaO was slightly higher than that of H/sub 2/S, using the literature data on the H/sub 2/S sorption. Significant sorption of COS takes place parallel to the sorption of H/sub 2/S in the coal gasification processes in which lime is used.