Process and amine-solvent absorbent for removing acidic gases from gaseous mixtures
AssigneeExxon Research & Engineering Co.
InventorsGuido Sartori, Frederic Leder
Life of this patent
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Abstract
Acidic gases are substantially removed from a normally gaseous mixture by a process comprising contacting the normally gaseous mixture with an amine-solvent liquid absorbent comprising (i) an amine comprised of at least about 50 mol % of a sterically hindered amine, and (ii) a solvent for said amine mixture which is also a physical absorbent for said acidic gases. The liquid absorbent may also include up to about 35 weight percent water.
Claims34
In a process for the removal of CO.sub.2 from a normally gaseous feed containing CO.sub.2 which comprises.
- (1) contacting said normally gaseous feed with an amine-solvent liquid absorbent comprising:
- (a) an amine, and
- (b) a solvent which solubilizes said amine and is a physical absorbent for said CO.sub.2, and
- (2) regenerating said absorbent at conditions whereby CO.sub.2 is desorbed from said absorbent, the improvement which comprises providing at least one sterically-hindered amine in said scrubbing solution as said amine and operating said process at conditions whereby the difference between the moles of CO.sub.2 absorbed at the end of step (1) (absorption step) and the moles of CO.sub.2 absorbed at the end of step (2) (desorption step) would be greater at the thermodynamic equilibrium of the vapor-liquid system (as determined from the vapor-liquid equilibrium isotherm of the reaction mixture) than in a CO.sub.2 gas scrubbing process utilizing a nonaqueous organic solvent and an amine wherein diisopropanolamine is the only amine utilized under similar conditions of gaseous feed composition, scrubbing solution composition, temperatures and pressures.
A process for the substantial removal of carbon dioxide in acidic gases from a normally gaseous feed containing CO.sub.2, which comprises:
- (1) contacting said normally gaseous feed with an amine-solvent liquid absorbent to absorb said carbon dioxide, wherein said amine-solvent liquid absorbent comprises:
- (a) a sterically hindered amine comprising 2-piperidine methanol or 2-piperidine ethanol,
- (b) sulfolane, and
- (c) up to about 35 weight percent of water;
- wherein said absorption is conducted at a temperature ranging from about 100 to about 1000 psig, and
- (2) desorbing the absorbed carbon dioxide from said solution at a temperature ranging from about 80.degree. to about 150.degree. C. and at a pressure ranging from about 15 to about 30 psia.
In a process for removing CO.sub.2 from gaseous feeds which comprises, in sequential steps:
- (1) contacting said feed with an amine-solvent liquid absorbent at conditions whereby said CO.sub.2 is absorbed into said scrubbing solution, said amine-solvent liquid absorbent being comprised of:
- (a) a nonaqueous organic solvent selected from the group consisting of hydrocarbons and functionalized hydrocarbons wherein the functional groups of said functional hydrocarbon is selected from the group consisting of oxygen, nitrogen, sulfur, phosphorus, silicon or halogen-containing groups,
- (b) an amine, and
- (c) water,
- (2) regenerating said scrubbing solution at conditions whereby CO.sub.2 is desorbed from said scrubbing solution,
- the improvement which comprises providing at least one sterically-hindered amine in said scrubbing solution as said amine and operating said process at conditions whereby the difference between the moles of CO.sub.2 absorbed at the end of step (1) (absorption step) and the moles of CO.sub.2 absorbed at the end of step (2) (desorption step) would be greater at the thermodynamic equilibrium of the vapor-liquid system (as determined from the vapor-liquid equilibrium isotherm of the reaction mixture) than in a CO.sub.2 gas scrubbing process utilizing a nonaqueous organic solvent and an amine wherein diisopropanolamine is the only amine utilized under similar conditions of gaseous feed composition, scrubbing solution composition, temperatures and pressures.
Dependencies are inferred from the claim text.