Process for treating a gas stream to selectively separate acid gases therefrom
AssigneeMobil Oil Corporation
InventorsBarry S. Marjanovich, Don A. Stang
Life of this patent
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Abstract
A treatment method for removing acid gases by contacting a sour gas stream with a solvent (e.g. an organic amine) which absorbs H.sub.2 S in preference to CO.sub.2 and hydrocarbons. The rich solvent is then regenerated by selectively separating the absorbed hydrocarbons in a first flash, a large portion of the CO.sub.2 in a high-temperature, low-pressure second flash tank, and the substantially all of the remaining acid gases in a high-temperature, low-pressure stripper. The regenerated solvent is recycled and the recovered acid gases are processed to recover sulphur from the H.sub.2 S. The CO.sub.2 recovered from the second tank is contacted with a second solvent to provide high-quality CO.sub.2.
Claims7
A method for treating a sour hydrocarbon gas stream containing hydrogen sulfide (H.sub.2 S) and carbon dioxide (CO.sub.2), said method comprising:
- passing said sour hydrocarbon gas stream into a high-pressure contactor vessel;
- contacting said sour hydrocarbon gas stream with a solvent within said contactor vessel to absorb H.sub.2 S and CO.sub.2 from said sour gas stream to produce a rich solvent;
- passing said rich solvent through a regeneration cycle to regenerate said rich solvent by removing substantial amounts of said H.sub.2 S and CO.sub.2 and any hydrocarbons absorbed by said solvent from said sour gas, said regenerating comprising:
- passing said rich solvent through a first flash tank having an operating temperature of from about 135.degree. to about 160.degree. F. wherein the pressure of said rich solvent is reduced to less than about 100 psig to separate only substantially all of the hydrocarbons from said rich solvent;
- recovering said separated substantially all of said hydrocarbons from said first flash tank and removing said separated hydrocarbons from said regeneration cycle for individual handling;
- heating said rich solvent from said first flash tank to a temperature of from about 215.degree. to about 240.degree. F. before passing it through a second flash tank where the pressure of the solvent is further reduced to less than about 25 psig to thereby selectively separate a substantial portion of said CO.sub.2 from said rich solvent;
- recovering said separated substantial portion of said CO.sub.2 from said second flash tank and removing said separated portion of said CO.sub.2 from said regeneration cycle;
- passing said separated CO.sub.2 from said second flash tank to a CO.sub.2 contactor vessel;
- and
- contacting said CO.sub.2 with a second solvent to absorb substantially all of any H.sub.2 S present in said CO.sub.2 to produce a second rich solvent;
- passing said rich solvent from said second flash tank to a stripper to separate substantially all of said H.sub.2 S remaining in said rich solvent to thereby regenerate said solvent;
- removing said separated, substantially all of said remaining H.sub.2 S from said stripper and removing said separated H.sub.2 S from said regeneration cycle for separate handling;
- and
- recycling said regenerated solvent to contact said sour gas stream.
Dependencies are inferred from the claim text.