Process for removing H.sub.2 S from sour gases with generation of a Claus feed gas

A process for treating a sour gas to prepare a fuel gas with relatively low amounts of hydrogen sulfide, and simultaneously prepare (1) a side stream of relatively pure carbon dioxide and (2) a side stream of a gas suitable for the feed to a Claus process having the required H.sub.2 S/CO.sub.2 ratio which comprises

• (A) feeding a gas containing CO.sub.2 and low amounts of H.sub.2 S to a first amine absorber containing an aqueous amine solution to produce a first off gas useful as a fuel gas containing lower amounts of H.sub.2 S, a major portion of the CO.sub.2 and a first rich amine,
• (B) feeding said rich amine loaded with H.sub.2 S and CO.sub.2 from said first amine absorber to a first amine regenerator wherein said amine is regenerated to produce a lean amine and a second off gas containing essentially CO.sub.2 and relatively large amounts of H.sub.2 S and said lean amine is recycled back to said first absorber,
• (C) feeding said second off-gas to a second amine absorber to produce a third off-gas containing substantially pure CO.sub.2 and a second rich amine,
• (D) feeding said second rich amine loaded with H.sub.2 S from said second absorber to said first regenerator together with said first rich amine from said first absorber, and
• (E) feeding a proportion of said second rich amine to a second amine regenerator wherein said amine is regenerated to produce an off gas suitable for the feed of a sulfur recovery process wherein the flow to said second amine regenerator is automatically controlled to provide a suitable off gas composition.