Scrubbing system yielding high concentration of hydrogen sulfide

Claim 1

In a process for the separation of at least hydrogen sulfide and carbon dioxide from a raw gaseous mixture in order to form a purified gaseous mixture, comprising scrubbing the gaseous mixture in a first scrubbing stage with a physical scrubbing liquid having a higher absorbability for hydrogen sulfide than for carbon dioxide, withdrawing from the scrubbing stage at least a first stream of scrubbing liquid loaded with hydrogen sulfide and carbon dioxide, and thermally regenerating the loaded scrubbing liquid to form (a) a gaseous phase containing hydrogen sulfide, and (b) regenerating scrubbing liquid, the improvement which comprises scrubbing said gaseous phase containing hydrogen sulfide in a second scrubbing stage with a stream of scrubbing liquid capable of absorbing the major quantity of H 2 S in said gaseous phase; and subjecting resultant second stream of scrubbing liquid loaded with hydrogen sulfide to a separation stage comprising rectification to form a bottoms of regenerated scrubbing liquid and an overhead of a gaseous phase rich in hydrogen sulfide, and further comprising a hydrogen sulfide enrichment stage provided downstream of the first scrubbing stage and upstream of the thermal regenerating and second scrubbing stage, separating in said stage CO 2 from the first loaded stream of scrubbing liquid, and employing a partial stream of resultant CO 2 -depleted scrubbing liquid stream withdrawn from the hydrogen sulfide enrichment stage to scrub said gaseous phase which contains hydrogen sulfide in said second scrubbing stage to form said resultant second stream of scrubbing liquid loaded with hydrogen sulfide, and subjecting another partial stream of resultant CO 2 -depleted scrubbing liquid to the thermal regenerating step to form said gaseous phase containing hydrogen sulfide.