Study of plasma dissociation mechanism of hydrogen sulfide

Summary form only given: Hydrogen sulfide plasma dissociation is a promising method for H₂S utilization. The conventional method based on multi-stage Claus Process is currently considered the industry standard. The Claus Process is based on partial oxidation of H₂S, which results in the production of sulfur and water. Plasma dissociation of H₂S follows direct dissociation path producing sulfur and hydrogen. It was estimated that if plasma dissociation of H₂S can be industrially realized with energy cost lower than 1 eV per H₂ molecule it can save the refining industry about up to 70times10¹² Btu/yr. Earlier thermodynamic equilibrium calculations show that the energy cost of thermal dissociation of molecule of H₂S cannot be less than 2.0 eV. Moreover, no chemical kinetics model exists that shows a significant improvement over thermodynamic equilibrium calculations. Nonetheless, results obtained from swirl flow reactors with microwave plasma discharge show that the effective cost of H₂S dissociation can be as low as 0.7 eV per molecule. The only explanation given for this low energy cost was the centrifugal effect of separation of solid sulfur with internal energy recuperation, which is more a hypothesis than a theory supported by experiment or detailed numerical modeling. This research is focused on the explanation of the above phenomena through the chemical kinetics modeling of the dissociation process as well as numerical simulation of heat and mass transfer in the plasma reactors used for the dissociation. The revision of kinetic mechanism is necessary, because many commonly known mechanisms are incomplete. Thus, the goal is not only to create a model predicting the experimentally achieved dissociation cost of 0.7 eV, but also experimentally confirm theoretical model conclusions.