THE EFFECT OF SURFACE AND THERMAL TREATMENTS ON GAMMA-AL2O3 AS A CATALYST OF THE CLAUS REACTION AT LOW-TEMPERATURE

gamma-Al2O3 was chemically or heat treated to modify its behavior as a catalyst of the Claus reaction at low temperature. The treatment by P or La impregnation altered substantially the surface donor properties , as revealed by NH3 adsorption, with no significant changes in the te xtural properties. However, the heat treatment by calcination at tempe ratures above 550 degrees C mostly affected the textural properties th rough sintering and crystallization. Using a model described in detail in a previous study the global reaction rate was calculated and the H 2S conversion curves in a fixed bed reactor were theoretically predict ed. The experimental results showed that the surface treatment increas ed largely the catalytic activity of alumina although the effects on t he H2S conversion in the reactor were small since it is a diffusion co ntrolled process. Changes in performance due to heat treatment were mu ch more pronounced allowing to conclude that the alumina performance c ould be substantially improved by optimization of the textural propert ies.