Equilibrium Analyses of H2S Conversion during Hot Gas Desulfurization

The complexity of the coal gas compositions and their reactions properties affect the sulfidation of H₂S with calcium-based-based sorbents, which is not easy to measure quantificationally. Using the ASPEN PLUS software, the reaction degrees between coal gas compositions can be obtained easily. The results show that the thermal decomposition of H₂S is affected by temperature greatly and the higher the temperature, the less stable H₂S is. Adding the H₂ composite will increase the stability of H₂S. When the H₂ molar content is higher than 2.5 %, the H₂S hardly dissociate. The higher the pressure, the less of H₂S decomposes. CO₂ and CO both can react with H₂S resulting to the decrease of H₂S equilibrium concentration. The water-gas-shift reaction is the most important one among the coal gas reactions. If H₂ and CO₂ are present in the reaction gas, CO and H₂O will appear in the off-gas largely and hence the CO and H₂O compound can not be introduced to the gaseous mixtures on the experiment of H₂S with calcium-based sorbents to some extent.