Influence of pressure on H2S oxidation. Experiments and kinetic modeling

The oxidation of H2S at different manometric pressures (0.6-40 bar), in the temperature range of 500-1000 K and under slightly oxidizing conditions (lambda = 2), has been studied. Experiments have been performed in a quartz tubular flow reactor. The results have shown that H2S conversion shifts to lower temperatures as the pressure increases. The kinetic model used in this work is based on a previous one proposed by the authors to describe H2S oxidation at atmospheric pressure, which has been updated with a H-2/O-2 reaction subset for high pressures. Model results match fairly well the experimental ones both from the present work and from the literature. The reaction pathways of H2S oxidation analyzed are similar to the ones at atmospheric pressure. The differences are found in the radicals that are involved in the oxidation process at the different pressures. For a given temperature it is shown that, under the operating conditions of this work, pressure will have a major role than the gas residence time in the oxidation rate.