METHOD FOR OBTAINING PURIFIED GAS STREAM Russian patent published in 2021 - IPC B01D53/14 

FIELD: gas industry.

SUBSTANCE: invention relates to a method for removing hydrogen sulfide and carbon dioxide from the source gas stream. H2S in the feed gas stream is converted to elemental sulfur in the Claus unit. At least part of the resulting gas stream is in contact with the water-depleted absorbing medium in the absorption zone at a pressure of 0.9 to 2 bar absolute. The aqueous depleted absorption medium being used contains one or more amines selected from: - polyamine in the absence of tertiary amine functional groups having a pKa value sufficient to neutralize carbamic acid, with polyamine having at least one primary amine functional group having a pKa value of less than 10.0 at 25°C, -polyamine in the absence of tertiary amine functional groups having a pKa value sufficient to neutralize carbamic acid, with polyamine having at least one secondary amine functional group having a pKa value for each sorbing nitrogen of less than 10.0 at 25°C.

EFFECT: method is improved in comparison with the method involving the treatment of Claus exhaust gases with (activated) MDEA. Efficient CO₂ removal is achieved while using a simplified queue with less equipment.

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