Kinetics of hydrogen sulfide decomposition in a DBD plasma reactor operated at high temperature

Abstract

The present study investigates the kinetics of hydrogen sulfide (H2S) decomposition into hydrogen and sulfur carried out in a nonthermal plasma dielectric barrier discharge (NTP-DBD) reactor operated at ∼430 K for in situ removal of sulfur condensed inside the reactor walls. The dissociation of H2S was primarily initiated by the excitation of carrier gas (Ar) through electron collisions which appeared to be the rate determining step. The experiments were carried out with initial concentration of H2S varied between 5 and 25 vol% at 150 mL/min (at standard temperature and pressure) flow rate in the input power range of 0.5 to 2 W. The reaction rate model based on continuous stirred tank reactor (CSTR) model failed to explain the global kinetics of H2S decomposition, probably due to the multiple complex reactions involved in H2S decomposition, whereas Michaelis-Menten model was satisfactory. Typical results indicated that the reaction order approached zero with increasing inlet concentration.