Kinetics of hydrodesulfurization on a cobalt-molybdenum/.gamma.-alumina catalyst. 1. Kinetics of the hydrogenolysis of thiophene

Abstract

The hydrogenolysis of thiophene on a commercial hydrodesulfurization CoMo/..gamma..-Al/sub 2/O/sub 3/ catalyst was studied in a bench-scale tubular reactor. The experimental conditions were varied over the following range: total pressure, 2-30 bar; temperature, 533-623 K; molar hydrogen to hydrocarbon ratios, 4-9. The experimental rate data were described by a set of Hougen-Watson rate equations for both the hydrogenolysis of thiophene into butene and the hydrogenation of butene into butane. The surface reactions between thiophene or butene and competitively adsorbed hydrogen were found to be the rate-determining step. Models with active site concentrations determined by the gas-phase conditions were also derived and comparisons were made with the data.