Kinetics of CaO desulfurization reaction and the effrects of some catalysts on the reaction were investigated by thermogravimetric analysis method. The results showed that the kinetic behavior of desulfurization could be modeled by a grain model. The activation energy of the surface reaction (Ea), the activation energy of the product layer diffusion (Ep), the rate constant (k), and the effective diffusivity (Ds) were determined using this model. The overall rates of desulfurization were controlled initially by the surface chemical reaction, and then shifted to product layer diffusion control. Some nitrates and oxides were chosen as catalysts and their catalytic effects on the kinetics of desulfurization were investigated. KNO3, NaNO3 could decrease the Ea, Ko, Ep, Dso, showing higher catalytic activity in low temperature region. Fe2O3, V2O5 could increase the Ea, ko, Ep, Dso, with higher catalytic activity in high temperature region. All these salts or oxides could improve both the initial reaction rate and final fraction conversion of CaO at the favorable temperatures. It is noted that Ea and Ep can not be used separately to evaluated activities of catalysts because Ea, Ko, and Ep, Dso are couple to each other. Nevertheless at certain temperatures k and Ds can be used to evaluate the effects of catalysts.

Key words: CALCIUM OXIDE, CATALYTIC ACTIVITY, POTASSIUM NITRATE, SODIUM NITRATE, DIFFUSION COEFFICIENTS