US 4,143,119 AGranted

Method and composition for inhibiting the corrosion of ferrous metals

AssigneeThe Dow Chemical Company

InventorsRobert G. Asperger, Leroy S. Krawczyk, Billy D. Oakes

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Abstract

A copper based corrosion inhibitor composition and a method for employing the same to prevent corrosion of metal in contact with acid-gases, i.e., hydrogen sulfide, carbonyl sulfide and carbon dioxide. Copper, or a copper compound and sulfur or a sulfur compound, is maintained in solution in contact with the metal under conditions of operation, particularly the thermal regeneration, which provide copper ions and sulfur atoms, particularly polysulfide moieties at the surface of the metal, e.g. copper sulfide is dissolved in an aqueous alkanolamine, monoethanolamine, solution used as an absorbent for acid-gas removal from sour-gas. The copper and sulfur moieties may be formed in situ or prepared and added in solution. The inhibitor has particular utility in protecting metal surfaces which are subject to corrosion as an incidence of the acid-gas content of either natural or synthetic gases.

Claims10

Dependent claims

A corrosion inhibiting composition for ferrous metal and its alloys, in contact with acid-gas stripping absorbent solutions selected from the group consisting of alkanolamines having the formula:

##STR3## wherein each R.sub.1 and R.sub.2 represents independently hydrogen, or --C(R.sub.3).sub.2 C(R.sub.3).sub.2 --OH and R.sub.3 represents an independently selected radical of hydrogen or C.sub.1-3 alkyl radical, sulfolane, (tetrahydrothiophene-1,1-dioxide), potassium carbonate or diglycolamines, each alone or in combination with one or more of each other as aqueous solutions or glycol solutions, said compositions consisting essentially of:
(a) a source of copper ion selected from the group consisting of copper metal, copper sulfide and copper salts,
(b) a source of sulfur atoms selected from the group consisting of 1) sulfur, or 2) hydrogen sulfide and/or COS in combination with an oxidizing agent which will produce in solution the sulfur atom, at least some of which is the polysulfide, under the conditions of operation in an acid-gas stripping plant which employs thermal regeneration techniques for separating the combined chemisorbed acid-gas from the stripping absorbent,
and (c) a solvent for (a) and (b) selected from the afore-enumerated absorbent solutions.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 05/807,089Filed 16 Jun 1977 · continuation in part
Priority: 12 Jan 1976
Granted: 6 Mar 1979
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

C23F 11/06
Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent: in…
B01D 3/322
Other features of fractionating columns ; Constructional details of fractionating columns not provided for in groups B01D3/16 - B01D3/30: reboiler…
B01D 53/1493
By absorption: selection of liquid materials for use as absorbents
B01D 53/526
Hydrogen sulfide: mixtures of hydrogen sulfide and carbon dioxide