Vanadium-amine corrosion inhibitor system for sour gas conditioning solutions

Claim 1

A corrosion inhibited composition consisting essentially of a. an aqueous alkanolamine solution in which the alkanolamine has the formula: ##STR2## wherein R' and R" independently represent hydrogen or --CR 2 CR 2 OH and wherein each R may be hydrogen or an alkyl radical of 1 or 2 carbon atoms, employed in CO 2 gas removal service, b. an anion containing vanadium in the plus 4 or plus 5 valence state and having a concentration in the composition of at least 100 parts per million and c. an amine co-inhibitor having a concentration in the composition of at least 0.4 weight percent and selected from the group consisting of N-aminoethylethanolamine, ethylenediamine, propylenediamine, piperazine, N-aminoethylpiperazine, methyliminobispropylamine and lower alkyl and N-hydroxyalkyl substituted derivatives thereof, where lower alkyl has one to four carbon atoms.

Claim 7

A method for inhibiting the corrosion of ferrous metal surfaces by an aqueous alkanolamine solution in which the alkanolamine has the formula: ##STR3## wherein R' and R" independently represent hydrogen or --CR 2 CR 2 OH and wherein each R may be hydrogen or an alkyl radical of 1 or 2 carbon atoms, employed in CO 2 gas removal service consisting essentially of adding to said aqueous alkanolamine solution a combination of a. an anion containing vanadium in the plus 4 or plus 5 valence state having a concentration in the alkanolamine solution of at least 100 parts per million and b. an amine co-inhibitor having a concentration in the alkanolamine solution of at least 0.4 weight percent and selected from the group consisting of N-aminoethylethanolamine, ethylenediamine, propylenediamine, piperazine, N-aminoethylpiperazine, methyliminobispropylamine and lower alkyl and N-hydroxyalkyl substituted derivatives thereof, where lower alkyl has one to four carbon atoms.

Claim 8

A method for inhibiting the corrosion of ferrous metal surfaces by an aqueous alkanolamine solution in which the alkanolamine has the formula: ##STR3## wherein R' and R" independently represent hydrogen or --CR 2 CR 2 OH and wherein each R may be hydrogen or an alkyl radical of 1 or 2 carbon atoms, employed in CO 2 gas removal service consisting essentially of adding to said aqueous alkanolamine solution a combination of a. an anion containing vanadium in the plus 4 or plus 5 valence state having a concentration in the alkanolamine solution of at least 100 parts per million and b. an amine co-inhibitor having a concentration in the alkanolamine solution of at least 0.4 weight percent and selected from the group consisting of N-aminoethylethanolamine, ethylenediamine, propylenediamine, piperazine, N-aminoethylpiperazine, methyliminobispropylamine and lower alkyl and N-hydroxyalkyl substituted derivatives thereof, where lower alkyl has one to four carbon atoms.

Claim 11

A method for inhibiting the corrosion of ferrous metal surfaces by an aqueous monoethanolamine solution employed in CO 2 gas removal service consisting essentially of adding to said aqueous monoethanolamine solution a combination of a. an anion containing vanadium in the plus 4 or plus 5 valence state and having a concentration in the monoethanolamine solution of at least 100 parts per million, the anion being derived from a vanadium compound selected from the group consisting of orthovanadates, metavanadates, pyrovanadates, vanadium oxides and vanadium halides and b. an amine co-inhibitor having a concentration of at least 0.4 weight percent in the monoethanolamine solution and selected from the group consisting of N-aminoethylethanolamine, ethylenediamine, propylenediamine, piperazine, N-aminoethylpiperazine, methylaminobispropylamine and lower alkyl and N-hydroxyalkyl substituted derivatives thereof, where lower alkyl has one to four carbon atoms.

Claim 12

A method for inhibiting the corrosion of ferrous metal surfaces by an aqueous monoethanolamine solution employed in CO 2 gas removal service consisting essentially of adding to said aqueous monoethanolamine solution a combination of a. an anion containing vanadium in the plus 4 or plus 5 valence state and having a concentration in the monoethanolamine solution of at least 100 parts per million, the anion being derived from a vanadium compound selected from the group consisting of orthovanadates, metavanadates, pyrovanadates, vanadium oxides and vanadium halides and b. an amine co-inhibitor having a concentration of at least 0.4 weight percent in the monoethanolamine solution and selected from the group consisting of N-aminoethylethanolamine, ethylenediamine, propylenediamine, piperazine, N-aminoethylpiperazine, methylaminobispropylamine and lower alkyl and N-hydroxyalkyl substituted derivatives thereof, where lower alkyl has one to four carbon atoms.