Abstract: This invention relates to a catalyst containing palladium and optionally chromium on an alumina which is used for the selective hydrogenation of acetylenic hydrocarbons in olefin gas streams. The catalyst is characterized by the use of an alumina support having a surface area of less than about 5 square meters per gram, a Hg pore volume of between about 0.2 and about 0.5 cubic centimeters per gram and wherein at least 40% of the pore volume is contained in pores having pore diameters of greater than about 10 microns.

Abstract: This invention relates to a catalyst containing palladium and optionally chromium on an alumina which is used for the selective hydrogenation of acetylenic hydrocarbons in olefin gas streams. The catalyst is characterized by the use of an alumina support having a surface area of less than about 5 square meters per gram, a Hg pore volume of between about 0.2 and about 0.5 cubic centimeters per gram and wherein at least 40% of the pore volume is contained in pores having pore diameters of greater than about 10 microns.

Abstract: An improvement on a process for decreasing the total sulfur content of off-gases from a Claus process is described wherein the sulfur dioxide-containing off-gas is mixed with a reducing gas and passed over a metallic reduction catalyst at elevated temperature to reduce the sulfur dioxide and other convertible sulfur compounds present to hydrogen sulfide followed by cooling of the thusly reduced gas stream at least partially by direct cooling with an aqueous quench liquid and removal of the hydrogen sulfide from the cooled gaseous stream by adsorption on an absorbent or absorbent for hydrogen sulfide, in which process the flow of either or both of the sulfur dioxide containing off-gas and the reducing gas to catalytic reduction is controlled by monitoring the sulfur dioxide content of the reduced gas stream.