Process for removal of hydrogen sulfide from a gas stream

Abstract

A process and system for removing hydrogen sulfide from a gaseous stream such as one of natural gas. A sour gas stream containing H.sub.2 S is contacted with a nonaqueous, water-insoluble sorbing liquor which comprises an organic solvent for elemental sulfur, dissolved elemental sulfur, an organic base to promote the reactions, and an organic solubilizing agent an agent suitable for maintaining the solubility of polysulfide intermediates which may otherwise separate when they are formed during operation of the process. Hydrogen sulfide (H.sub.2 S) gas is sorbed into this liquor and then reacts with the dissolved sulfur in the presence of the base to form polysulfide molecules. The solution is then sent to a reactor where sufficient residence time is provided to allow the polysulfide forming reactions to reach the desired degree of completion. From the reactor, the solution flows to a regenerator where the solution is oxidized (e.g., by contact with air), forming dissolved elemental sulfur and water. The temperature of the solution is then lowered, forming sulfur crystals, which are easily removed by gravity settling, filtration, centrifuge, or other separation method. Enough sulfur remains dissolved in the solution following removal of the sulfur crystals that when this solution is reheated and returned to the absorber a sufficient amount of sulfur is present to react with the inlet H.sub.2 S gas.

Dependencies are inferred from the claim text.