CATALYSTS MACROPOROSITY AND THEIR EFFICIENCY IN SULFUR SUB-DEW POINT CLAUS TAIL GAS TREATING PROCESSES

The efficiency of 4 samples of alumina catalyst has been studied exper imentally in the course of the Claus 'tail gas' treating processes at the sulphur sub-dew point (TGTP). The samples were characterized by th e same chemical and crystallographic composition, the same volume of m icropores, the same surface area and the same catalytic activity but d iffered appreciably in the volume of macropores. An increase in the ef fective operation time of the catalysts before breakthrough of unrecov erable sulphur containing compounds, with the increasing macropore vol ume has been established. A theoretical model of the TGTP has been con sidered and it has been shown that the increase in the sulphur capacit y of the catalysts with a larger volume of macropores is due to an inc rease in the catalysts efficiency factor and a slower decrease in thei r diffusive permeability during filling of micropores by sulphur.