Corrosion inhibitors for alkanolamines
AssigneeThe Dow Chemical Company
InventorsEdwin R. Henson, Tipton T. Masterson, Joel G. Courtwright
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Abstract
This invention relates to a corrosion inhibiting composition for ferrous metals and its alloys in gas conditioning service using aqueous monoethanolamine to scrub carbon dioxide. The corrosion inhibiting composition includes a thiourea-amine-formaldehyde based polymer and, in the preferred embodiment, also includes a nickel ion producing material.
Claims8
A corrosion inhibiting composition for ferrous metals and its alloys in gas conditioning service using aqueous monoethanolamine to scrub carbon dioxide containing oxygen comprising:
- (a) a thiourea-aminopiperazine-formaldehyde polymer, and
- (b) a nickel ion producing material selected from the group consisting of nickel (II) salts, nickel (II) complexes and combinations thereof, wherein said thiourea-aminopiperazine-formaldehyde polymer is combined with said nickel ion producing material in a ratio of from 2 to 4 parts thiourea-aminopiperazine-formaldehyde polymer to 1 part nickel ion producing material.
A process for the preparation of a corrosion inhibiting composition comprising the steps of:
- (a) preparing an aqueous solution by mixing a thiourea with a primary or secondary amine;
- (b) adding formaldehyde to said aqueous solution with stirring and under conditions such that temperature is maintained at or below 50.degree. C.;
- (c) preparing a solution of nickel ion producing material in alcohol by mixing a nickel ion producing material selected from the group consisting of:
- nickel (II) salts, nickel (II) complexes and combinations thereof in alcohol and combining the resulting solution with hydrochloric acid;
- (d) separating the nickel ion producing precipitate from said solution;
- and
- (e) combining said aqueous solution with said nickel ion producing precipitate in a ratio of 2 to 4 parts aqueous solution to 1 part nickel ion producing precipitate.
Dependencies are inferred from the claim text.