EFFECT OF HCL ON SULFIDATION OF CALCIUM-OXIDE

The sulfidation of calcined limestone and dolomite was studied in an a mbient pressure quartz thermogravimetric analyzer (TGA) reactor unit a t 982-degrees-C. Comparative sulfidation experiments were performed wi th and without the presence of HCI using both calcined limestone and d olomite in two particle sizes. The reactant gas contained H2S, H-2, H2 O, and nitrogen. The H2S and HCl content of the reactant gas was chose n to represent oxygen-blown and air-blown coal gasification environmen ts. The results of this study indicate that the addition of both steam and HCI enhances the overall rate of sulfidation reaction and that th e rate is linearly dependent on the HCI content of the reactant gas up to 100 ppm for limestone and 150 ppm for dolomite. The sulfidation re action rate is insensitive to HCI concentrations above these levels fo r these sorbents. The results obtained in this study suggest that the enhancement of the sulfidation reaction rate in the presence of HCI is caused by surface phenomena that are related to the presence of steam .