New experimental data and kinetic rate expression for the Claus reaction

The modified Claus process is the most common method for the conversion to sulphur of the hydrogen sulphide contained in sour oil and natural gas. This study focuses on the relatively unexamined reaction kinetics of the front-end reaction furnace in the Claus process, where sulphur production occurs and hydrocarbon contaminants are destroyed. Specifically, the kinetics of the reaction between H₂S and SO₂ were investigated under actual Claus plant temperatures and residence times, filling a gap in previous studies which primarily focused on catalytic conditions. Experiments were executed in an isothermal, laboratory-scale plug-flow reactor, operating at temperatures ranging from 850 to 1150 °C and residence times between 0.05 and 1.2 seconds. The results of the experiments provided new kinetic data that allowed for the development of a reaction rate expression. The proposed expression effectively correlates experimental data for H₂S and SO₂ with a deviation of 12% and 18% respectively. Furthermore, it extrapolates accurately to equilibrium conversion values, and the derived Arrhenius parameters predict the heat of reaction with an error margin of only 0.05%. The results contribute significant insights into the kinetics of sulphur production in Claus plants.