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.

Processes:

Selective H₂S removal

Products:

Eastman AdapT 100 series

Requirements:

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.

Challenges

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.