CS207959B1 - Mixed inhibitor of the metal corrosion - Google Patents

Description

(54) Mixed metal corrosion inhibitor

The present invention relates to a mixed metal corrosion inhibitor applied to the protection of metal parts of equipment used for the extraction, storage and transport of natural gas or town gas.

Some components of the gas, such as carbon dioxide, hydrogen sulfide, oxygen, and organic acids, together with water, create a corrosively active environment that causes the deterioration of metal containers, pipes, fittings and other metal accessories. The action of these components is often enhanced by entrained particles of a chemical nature, for example chlorides, or a mechanical nature, for example sand. The form of corrosion attack can be flat, pitting and intercrystalline together with the abrasive action of the entrained rock.

One of the other forms of corrosion as a result of material fatigue is the so-called corrosion cracking.

Reducing the corrosion of this system is very important, although in principle there are known ways of solving corrosion protection. Either expensive corrosion-resistant metal materials can be selected, or a plastic coating can be applied to the metal surface, or corrosion inhibitors can be applied using cheaper metal materials.

In practice, alkylphenols, calcium salts of sulfoacids, polyesters, aliphatic amine hydrochlorides, a mixture of alkylpyridinium bases, condensate 207959, pyridine products with chloromethylated hydrocarbons and the like are used as corrosion inhibitors.

The mixed metal corrosion inhibitor according to the invention consists essentially of active substances containing 5 to 30% by weight of volatile alkalinizing agents, for example morpholine, cyclohexylamine, ammonia, hydrazine, 5 to 50% by weight of film-forming amines C ₁₀ to C ₂₅ such as octadecylamine and 10 up to 40% by weight of unsaturated fatty acid alkanolamides or imidazoline and derivatives thereof in a concentration of 5 to 25% by weight or esters of fatty acids with higher alcohols in a concentration of 5 to 25% by weight.

According to a further feature, 1 to 5 parts of the active ingredient comprises from 5 to 50 parts of a solvent, for example methanol, ethanol, a hydrocarbon condensate or a mixture thereof.

The mixed corrosion inhibitor of the invention is first applied to coal gas extraction probes. After dissolution in methanol, ethanol or hydrocarbon condensate, it is dosed as a two to twenty percent solution by pump into the extraction probe in an amount of 2001 / one million cubic meters of extracted gas. Extraction of the gas is carried out only after 24 hours of action of the inhibitor which forms a protective film on the metal coating. After the start of gas production, the first week is dosed 200

1 / million m ^{3 of} gas, the next week 501 / million m ^{3 of} gas and then still 10 1 / million m ^{3 of} gas.

The invention is illustrated by the following examples of a specific embodiment.

Example 1

Mixed corrosion inhibitor containing wt. % cyclohexylamine, wt. % octadecylamine; alkanolamides of unsaturated fatty acids are applied in the form of a 10% alcoholic solution. In laboratory tests simulating real corrosion conditions, the mixed inhibitor showed 93% inhibitory activity.

Example 2

Mixed corrosion inhibitor containing wt. % morpholine, wt. % octadecylamine, wt. % of unsaturated fatty acid alkanolamides, wt. % imidazoline (imidazole) derivatives and% wt. fatty acid esters of higher alcohols are applied as a 5% solution in methanol-hydrocarbon condensate in a ratio of 1; 2. In the laboratory tests, the mixed inhibitor showed 95% inhibitory activity.

Example 3

Mixed corrosion inhibitor containing wt. % cyclohexylamine, wt. % octadecylamine, wt. % coconut fat diethanolamide, wt. % imidazole alkylderiylates and% wt. fatty acid esters of higher aliphatic alcohols are applied as a 5% solution in a hydrocarbon condensate. In a laboratory experiment, the mixed inhibitor showed 95% inhibitory activity.

Claims (4)

SUBJECT OF THE INVENTION Mixed corrosion inhibitor, characterized in that it contains 5 to 30% by weight of alkalizing agents, 5 to 50% by weight of film-forming amines C ₁₀ to ₂₅ and 10 to 40% by weight of unsaturated fatty acid alkanolamides as active substances. 2. Mixed inhibitor according to claim 1, characterized in that it contains imidazoline and its derivatives in a concentration of 5 to 25% by weight. 3. The mixed inhibitor of claim 1, further comprising fatty acid esters of higher alcohols in a concentration of 5 to 25% by weight. Mixed inhibitor according to one of Claims 1 to 3, characterized in that 5 parts to 50 parts of solvent per 1 part of active ingredients.