A sterically hindered amino acid promoted acid gas scrubbing process

Claim 2

A process for the removal of C0 2 from a gaseous stream containing C0 2 which comprises (1) contacting said gaseous stream in an absorption step with an aqueous absorbing solution comprising (a) a basic alkali metal salt or hydroxide selected from 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 selected from N-secondary butyl glycine and a mixture comprising: (i) at least one sterically hindered monosubstituted amino acid and (ii) at least one tertiary amino acid, said amino acids being defined by the general formulae: (sterically hindered monosubstituted amino acid) and (tertiary amino acid) wherein R is either hydrogen or methyl', R' and R" are each alkyl or substituted alkyl radicals having 1 to 5 carbon atoms, and R"' is a linear alkyl or substituted linear alkyl radical having from 1 to 6 carbon atoms; and (2) in a desorption and regeneration step, desorbing at least a portion of the absorbed C0 2 from said absorbing solution.

Claim 3

A process according to claim 1 wherein said activator or promoter is comprises admixture of at least one sterically hindered monosubstituted amino acid and at least one tertiary amino acid.

Claim 4

3 . A process according to claim 1 or 2 wherein the aqueous solution contains 10 to about 40% by weight of potassium carbonate as said basic alkali metal salt or hyroxide.

Claim 5

A process according to claims 2 or 3 wherein the aqueous solution contains 2 to about 20% by weight of said sterically hindered monosubstituted amino acid and 2 to about 20% by weight of said tertiary amino acid.

Claim 6

A process according to claims 2,3, or 4 wherein said sterically hindered monosubstituted amino acid is N-secondary butyl glycine and said tertiary amino acid is N-methyl N-secondary butyl glycine.

Claim 7

6 . A process for the removal of C0 2 from a gaseous stream containing C0 2 in accordance with claim 1, which comprises, in sequential steps, (1) contacting the gaseous stream with an absorbing solution comprising (a) from about 20 to about 30% by weight of potassium carbonate, and (b) an activator or promoter system for the potassium carbonate, comprising (i) from about 5 to about 10% by weight of N-secondary butyl glycine, and (ii) from about 5 to about 15% by weight of N-methyl-N-secondary butyl glycine, (c) the balance of the solution comprising water and additives selected from antifoaming agents, antioxidants and corrosion inhibitors, wherein said contacting is conducted at conditions whereby C0 2 is absorbed in said absorbing solution and the temperature of the absorbing solution is in the range from about 35 to about 150°C, and the pressure in the absorber is in the range from about 100 to about 1500 psig; and (2) regenerating said absorbing solution at conditions whereby C0 2 is desorbed from said absorbing solution, wherein the regeneration takes place at temperatures ranging from about 35 to about 150 0 C and at pressures ranging from about 5 to about 100 psig.

Claim 8

A process according to claim 6wherein the absorbing solution from the regeneration step is recycled for reuse in the absorption step.

Claim 9

An absorption 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 sterically hindered monosubstituted amino acid, and (c) 2 to about 20% by weight of a tertiary amino acid, said amino acids being defined by the general formulae: (sterically hindered monosubstituted amino acid) and (tertiary amino acid) wherein R is either hydrogen or methyl, R' and R" are each alkyl or substituted alkyl radicals having 1 to 5 carbon atoms, and R"' is a linear alkyl or substituted linear alkyl radical having from 1 to 6 carbon atoms and (d) the balance, water.

Claim 10

An absorption 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 sterically hindered monosubstituted amino acid, and (c) 2 to about 20% by weight of a tertiary amino acid, said amino acids being defined by the general formulae: (sterically hindered monosubstituted amino acid) and (tertiary amino acid) wherein R is either hydrogen or methyl, R' and R" are each alkyl or substituted alkyl radicals having 1 to 5 carbon atoms, and R"' is a linear alkyl or substituted linear alkyl radical having from 1 to 6 carbon atoms and (d) the balance, water.

Claim 11

An absorption composition comprising: (a) 20 to 30% by weight of potassium carbonate, (b) 5 to about 10% by weight of N-secondary butyl glycine, (c) 5 to about 10% by weight of N-methyl-N-secondary butyl glycine, and optionally (d) the balance, water.

Claim 12

An absorption composition comprising: (a) 20 to 30% by weight of potassium carbonate, (b) 5 to about 10% by weight of N-secondary butyl glycine, (c) 5 to about 10% by weight of N-methyl-N-secondary butyl glycine, and optionally (d) the balance, water.

Claim 13

A composition according to claims 8 or 9 wherein the composition includes one or more antifoaming agents, antioxidants or corrosion inhibitors.