Method and system for increasing the absorption selectivity of H2S from a gas containing CO2 and H2S
OwnerDavid K. Stevens, Kevin M. Robertson +2inventors
InventorsDavid K. Stevens, Kevin M. Robertson, Mark R. Tonjes, Lindsay Wedel Dreitzler
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Abstract
A system and a method for increasing the selectivity of H2S absorption in an aqueous amine treating processes for streams containing high CO2:H2S ratio mixtures in an absorption column by maintaining the temperature in the absorption column by withdrawing, cooling and returning cooled aqueous amine to the column at at least one location intermediate the sour gas inlet to the column and the lean gas outlet from the column.
Claims19
A method for increasing the H2S selectivity of absorption from a gas containing CO2 and H2S in a ratio where the CO2 is significant to the concentration of H2S in an amine treating process, the method comprising:
- a) passing the gas into an aqueous amine-contacting vessel with the aqueous amine;
- b) maintaining the temperature in the contacting vessel at a temperature between 50 and 150° F. by withdrawing cooling and returning to the contacting vessel a quantity of the aqueous amine;
- c) recovering a rich aqueous amine solution from the contacting vessel, the rich amine solution being selectively enriched with H2S;
- d) recovering an H2S stream having an H2S content of at least about 10 volume percent H2S from the rich aqueous amine from the contacting vessel;
- and,
- e) recovering the gas at least partially depleted of H2S from the contacting vessel.
A system for increasing the H2S selectivity of absorption from a gas containing CO2 and H2S in a CO2:H2S ratio of at least about 3 in an amine treating system, the system comprising:
- a) an amine contacting vessel including at least two sections having a gas:liquid contacting efficiency of at least about 1 theoretical tray and having a sour gas inlet, a lean aqueous amine inlet, a rich aqueous amine outlet and an outlet for a lean gas stream having a reduced H2S content;
- b) at least one aqueous amine withdrawal line positioned to withdraw aqueous amine from the contacting vessel;
- c) a heat exchanger positioned in fluid communication with the aqueous amine withdrawal line to cool the aqueous amine to a selected temperature to produce a cooled aqueous amine;
- and,
- d) at least one return line in fluid communication with the heat exchanger and the contacting vessel to return at least a portion of the cooled aqueous amine to the contacting vessel.
Dependencies are inferred from the claim text.