Patent ID: 7837965

Claim:
A process for reducing the concentration of H 2 S in a feed gas stream comprising: contacting in a first contact zone the feed gas with a recycled aqueous scrubbing liquid comprising cooled liquid from a reflux drum of a sour water stripper, the cooled liquid comprising aqueous ammonia and hydrogen sulfide, producing a semi-sweet gas stream with a lower concentration of H 2 S than the feed gas and a rich liquid solution; mixing the rich liquid solution with overhead vapor from a sour water stripper, creating a mixture; controlling the temperature of the mixture to prevent condensation of ammonium bisulfide; separating the mixture in the reflux drum, to produce a vapor product stream and a flashed liquid; releasing the vapor product stream from the reflux drum; passing a portion of the flashed liquid to a means of cooling to reproduce the recycled aqueous scrubbing liquid; and returning a portion of the flashed liquid to the sour water stripper as reflux.