Acid gas enrichment

In cases where a gas stream contains elevated amounts of carbon dioxide (CO2) in comparison with hydrogen sulfide (H2S), the produced acid gas stream may be too diluted in H2S to allow direct processing in the Claus sulfur recovery unit. In such cases, an acid gas enrichment (AGE) step can be used to upgrade the low-quality acid gas to higher quality Claus plant feed or to smaller volume streams that are suitable for reinjection.


The objective of the selective H2S removal process is to have  maximum separation between CO2 and H2S,  in order to produce a gas enriched in H2S to the greatest possible extent.



As with Claus tail gas treatment units, the treatment conditions for acid gas enrichment are challenging because of the low pressure and maximum selectivity requirements. MDEA-based solvents are preferred because of the inherent selectivity of a tertiary amine like MDEA, which favors H2S absorption over CO2.

Eastman’s answer

Eastman AdapT solvents are formulated to maximize the selectivity beyond the performance associated with unformulated MDEA.