Process for removing acid gases using a basic salt activated with a non-sterically hindered diamine
AssigneeExxon Research & Engineering Co.
InventorsGuido Sartori, Chang J. Kim, Michael T. Melchior, David W. Savage
Life of this patent
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Abstract
Acidic gases containing carbon dioxide are removed from a normally gaseous mixture by absorbing CO.sub.2 from the gaseous mixture with an aqueous solution comprising a basic alkali metal salt or hydroxide and an activator or promoter system for the salt or hydroxide which contains (i) at least one non-sterically hindered diamine defined as having both a primary and a tertiary amino moiety wherein the primary amino moiety is attached to a primary carbon atom, and (ii) an amino acid, and desorbing at least partially the absorbed CO.sub.2 from the aqueous solution.
Claims15
A process for the removal of CO.sub.2 from a gaseous stream containing CO.sub.2 which comprises (1) in an absorption step, absorbing CO.sub.2 from said gaseous stream with an aqueous absorbing solution comprising (a) a basic alkali metal salt or hydroxide selected from the group consisting of alkali metal bicarbonates, carbonates, hydroxides, borates, phosphates and their mixtures, and (b) an activator or promoter system for said basic alkali metal salt or hydroxide comprising (i) at least one non-sterically hindered diamine which is defined as a compound containing both a primary and a tertiary amino moiety wherein the primary amino moiety is attached to a primary carbon atom, and (ii) an amino acid which has the capability to increase the solubility of said diamines in alkaline aqueous conditions at elevated temperatures, and (2) in a desorption and regeneration step desorbing at least a portion of the absorbed CO.sub.2 from said absorbing solution.
A process for the removal of CO.sub.2 from a gaseous stream containing CO.sub.2 which comprises, in sequential steps, (1) contacting the gaseous stream with an absorbing solution comprising (a) from about 20 to about 30 weight percent of potassium carbonate and (b) an activator or promoter system for the potassium carbonate comprising (i) from about 5 to about 15 weight percent of at least one non-sterically hindered diamine which is defined as a compound containing both a primary and a tertiary amino moiety wherein the primary amino moiety is attached to a primary carbon atom, and (ii) from about 5 to about 10 weight percent of pipecolinic acid or N-secondary butyl glycine, and (c) the balance of said absorbing solution being comprised of water and additives selected from the group consisting of antifoaming agents, antioxidants and corrosion inhibitors, wherein said contacting is conducted at conditions whereby CO.sub.2 is absorbed in said absorbing solution and the temperature of the absorbing solution is in the range from about 35.degree. to about 150.degree. C., and the pressure in the absorber is in the range from about 100 to about 1,500 psia;
- and (2) regenerating said absorbing solution at conditions whereby CO.sub.2 is desorbed from said absorbing solution, wherein the regeneration takes place at temperatures ranging from about 35.degree. to about 105.degree. C. and at pressures ranging from about 5 to about 100 psig.
An aqueous acid gas scrubbing composition comprising:
- (a) 10 to about 40% by weight of an alkali metal salt or hydroxide, (b) 2 to about 20% by weight of a non-sterically hindered diamine containing both a primary and a tertiary amino moiety wherein the primary amino moiety is attached to a primary carbon atom, (c) 2 to about 20% by weight of an amino acid which has the capability to increase the solubility of said diamines in alkaline aqueous conditions at elevated temperatures, and (d) the balance, water.
An aqueous acid gas scrubbing composition comprising:
- (a) 20 to 30% by weight of potassium carbonate, (b) 5 to about 15% by weight of N-(3-aminopropyl)-2-pipecoline, (c) 5 to about 10% by weight of pipecolinic acid, and (d) the balance, water.
Dependencies are inferred from the claim text.