Process and apparatus for removal of h.sub.2 s with separate absorber

Abstract

A method and apparatus including a reaction chamber interposed in a polyvalent metal redox solution flow path between an absorber chamber and an oxygenation chamber, including one or more oxygenation stages, for contact in the reaction chamber of H.sub.2 S-laden catalytic polyvalent metal redox solution form the absorber chamber with highly oxidized polyvalent metal redox solution from the last oxygenation stage to accomplish oxidation of the dissolved H.sub.2 S species by interaction with the oxidized redox catalyst essentially in the absence of gaseous dissolved oxygen. The highly oxidized polyvalent metal redox solution, including Fe.sup.+3 or V.sup.+5, contacts the H.sub.2 S-laden solution from the absorber chamber for reoxidation of the dissolved HS.sup.-, S.sup.= and any of the polyvalent metal sulfur compounds (presumably a chelated iron sulfide or a vanadium sulfide), to avoid formation of sulfate or thiosulfate salts which reduce the yeild of sulfur and build up in the solution. To avoid the formation of crystals of iron sulfide or crystals of vanadium sulfide, thereby avoiding loss of polyvalent metal, the residence time of the redox solution after contact with the H.sub.2 S-containing gas and prior to contacting with the oxidized metal redox solution is limited to a relatively short time. Flow of solution from the last oxygenation stage, preferably through a valve or other circulation control device, to the reaction chamber provides controlled and continuous elemental sulfur formation in the reaction chamber.