A THERMOGRAVIMETRIC STUDY OF THE REACTION OF HYDROGEN-CHLORIDE GAS WITH CALCINED LIMESTONE - DETERMINATION OF KINETIC-PARAMETERS

The reaction of hydrogen chloride gas with calcined limestone was carried out experimentally using a thermorecording balance. Reaction temperatures in the range 310-670-degrees-C and HCl concentrations in the range 0.5-5.0 mol.% were used. Determination of the kinetic parameters was carried out using calcined AR grade calcium carbonate powder to avoid competing reactions due to impurities. The analysis was based on initial reaction rates. Gas phase mass transfer effects were minimized and in the absence of internal diffusion, the reaction was found to be first order with respect to HCl gas concentration. The activation energy for the system was found to be around 22000 J mol-1. Through study of comparative reaction rates, the reaction was found to be more rapid than those of other reactive gases which might be present in flue gases.