Process for recovery of sulfur from acid gases

摘要

Elemental sulfur is recovered from the H2S present in gases derived from fossil fuels by heating the H2S with CO2 in a high-temperature reactor in the presence of a catalyst selected as one which enhances the thermal dissociation of H2S to H2 and S2. The equilibrium of the thermal decomposition of H2S is shifted by the equilibration of the water-gas-shift reaction so as to favor elemental sulfur formation. The primary products of the overall reaction are S2, CO, H2 and H2O. Small amounts of COS, SO2 and CS2 may also form. Rapid quenching of the reaction mixture results in a substantial increase in the efficiency of the conversion of H2S to elemental sulfur. Plant economy is further advanced by treating the product gases to remove byproduct carbonyl sulfide by hydrolysis, which converts the COS back to CO2 and H2S. Unreacted CO2 and H2S are removed from the product gas and recycled to the reactor, leaving a gas consisting chiefly of H2 and CO, which has value either as a fuel or as a chemical feedstock and recovers the hydrogen value from the H2S.