THERMOLYSIS OF HYDROGEN-SULFIDE IN AN OPEN-TUBULAR REACTOR

This paper addresses the kinetic aspects of the thermal decomposition of H2S in a flow reactor. Experiments conducted in a quartz tube with argon/H2S feed over a wide composition spectrum (20-100% H2S) at four temperatures (1030-1070 K) show that the reaction is essentially first order in H2S partial pressure. Theoretical models based on a free radical mechanism involving the abstraction of hydrogen from H2S as the rate-determining step show the linear dependency of thermolysis rate on reactant composition. Hydrogen yield also increases monotonically with feed composition at all temperatures. Interestingly, the activation energy for H-2 production of 200 kJ mol(-1) is lower than that for the global decomposition reaction of about 241 kJ mol(-1), consistent with the view that the initiation step requiring the breaking of the H-S bond is the rate-controlling step rather than the termination involving the combination of two hydrogen radicals.