Corrosion inhibitors for an aqueous medium (Nalco Company)

PATENT
Corrosion inhibitors for an aqueous medium (Nalco Company)
Publication number
US8105987 B2
Application number
12/245,806
Publication date
Jan 31, 2012
Also published as
US20100084611
Inventors
Erick J. Acosta, Jeffery Caleb Clark
Original Assignee
Nalco Company
Abstract
One or more methods for inhibiting corrosion in an aqueous medium that contain a composition with a specified generic formula are disclosed. The aqueous medium can be contained in an oil or gas pipeline or refinery.
FIELD OF THE INVENTION
The field of the invention pertains to corrosion inhibitors for an aqueous medium, e.g. an aqueous medium in an oil and gas pipeline or refinery.
BACKGROUND OF THE MENTION
Corrosion of metal surfaces in an aqueous medium has long been a problem for the oil and gas industry. It is well known that during the production of oil and gas several other corrosive components are present such as brines, organic acids, carbon dioxide, hydrogen sulfide, and microorganisms. These aggressive constituents can cause severe corrosion to metal pipes, which are often made of low-alloy steels. This problem is even more troublesome in deep-sea operations where replacement of corroded equipment is difficult and costly. Therefore, it is common practice to employ corrosion inhibitors during the production, transportation, storage, and separation of crude oil and natural gas.
Corrosion inhibitors are usually surface-active compounds that form protective coatings on the surface of metal components, which come in contact with corrosive environments, and thus suppress corrosion. Common corrosion inhibitors are composed of amines, condensation products of fatty acids with polyamines, e.g. imidazolines, or quaternary ammonium compounds. Among the most frequently used corrosion inhibitors in crude oil and natural gas extraction are imidazoline derivatives. Alternative corrosion inhibitors that can be used alone or in combination with known corrosion inhibitors are being sought by the industry.
SUMMARY OF THE INVENTION
The present invention provides for a method of inhibiting corrosion in an aqueous medium comprising: adding to the aqueous medium an effective corrosion inhibiting amount of a synergist, a synergist when H2S is present in the aqueous medium, or no synergist when H2S is present in the aqueous medium, and a composition comprising the following formula and optionally salts thereof:
•where R1 is CnH2n+1, wherein n=0 to 12; benzyl; or H;
•where R2 is a C1 to C22 alkyl;
•where R3 is CnH2n+1, wherein n=0 to 12; benzyl; or H;
•where X− is a halogen or a carboxylate and wherein X− is only present when both R1 and R3 are present;
•where Y═(CH2)n, wherein n is 1 to 8; and
•wherein R3 and R1 cannot be hydrogen at the same time.
The present invention also provides for a method of inhibiting corrosion in an aqueous medium comprising: adding to the medium an effective corrosion inhibiting amount of a synergist, a synergist when H2S is present in the aqueous medium, or no synergist when H2S is present in the aqueous medium, and a composition comprising the following formula and optionally salts thereof:
•where R1 is CnH2n+1, wherein n=0 to 12; benzyl; or H;
•where R2 is CnH2n+1, wherein n=1 to 22;
•where X═Cl, Br, or I
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