PROCESS FOR TREATING A MIXED FEED OF HYDROGEN SULFIDE GAS AND AMMONIA GAS TO PRODUCE AMMONIUM THIOSULFATE AND INCLUDING METHODOLOGY FOR EMISSIONS CONTROL

摘要

This invention relates to production of an aqueous solution containing ammonium thiosulfate from a feed gas containing hydrogen sulfide (H2S) and ammonia (NH3). Sufficient separation of feed gas H2S from NH3 is achieved by controlling individual NH3 and H2S absorption mass-transfer rates in a single co-current stage, whereby a first gas contacts a first liquid containing ammonium bisulfite (ABS). Substantially more NH3 is absorbed than H2S, converting ABS to diammonium sulfite (DAS). A portion of DAS reacts with a sufficiently small portion of H2S to produce ATS and leaves as a second liquid stream. A larger portion of H2S leaves as a second gas stream. The second gas stream is oxidized to sulfur dioxide (SO2) comprising a third gas stream. The third gas stream contacts the second aqueous stream in a second contact stage whereby DAS in the second liquid stream is converted to ABS and returned to the first contacting zone.