RU2083720C1 - Inhibitor in mineralized mediums comprising hydrogen sulfide - Google Patents

Abstract

FIELD: protection metals against corrosion in mineralized mediums comprising hydrogen sulfide; oil and gas recovery, oil processing industry. SUBSTANCE: proposed inhibitor contains 55.0-95 mass % of pyran fraction, 3.5-7.0 mass % of alkyl imidazoline, 0.5-3.0 mass % of nonionic surfactant and toluene. Waste of 4,4-dimethyl-1,3-dioxane may be used for production of said inhibitor. EFFECT: improved efficiency of desired inhibitor, decreased its cost. 3 tbl

Description

 The invention relates to the protection of metals from corrosion and can be used in the oil and gas production and processing industries to protect low alloy steels from corrosion-mechanical destruction (CMR) in hydrogen sulfide-containing mineralized environments, such as wet hydrogen sulfide-containing natural gas and oil condensate, drainage water from processing plants oil and gas.

It is known to use trialkylbenzylmethylammonium chloride or fluoride, or iodide, additionally containing actidecylamine, quinoline or its derivatives as an inhibitor of hydrogen sulfide corrosion and hydrogenation of steel [1]
The closest in technical essence and the achieved result to the proposed one is an inhibitor for protection against corrosion of the oil and gas industry in hydrogen sulfide-containing mineralized media containing amine, nonionic surfactant and aromatic hydrocarbon [2]
The disadvantage of the prototype is the impossibility of its use in conditions of corrosion-mechanical destruction of steels.

 The technical result of the use of the invention is the development of a highly effective inhibitor of hydrogen sulfide corrosion KMP low alloy steels during transportation of hydrogen sulfide associated gas, oil condensate and drainage water of oil refining plants.

 The essence of the invention lies in the fact that the inhibitor in hydrogen sulfide-containing mineralized media "Reactor-1", contains, by weight.

Piran fraction 55 95
Alkylimidozoline 3.5 7
Nonionic surfactant 0.5 3
Toluene Else
The pyran fraction is a waste product from the production of 4,4-dimethyl-1,3-dioxane and is currently being burned. Alkylimidozoline is obtained by the reaction of ammonia with unsaturated hydrocarbons at 200 ^o C and a pressure of about 1000 at.

 An inhibitor is prepared by mixing under normal conditions the pyran fraction, alkylimidosoline, nonionic surfactant and toluene.

 Physico-chemical properties of the inhibitor: "Reakor-1" is a light brown or brown liquid with a specific odor; density 1.1 kg / l; soluble in water, acetone, alcohol; viscosity 74.5 Art.

 Studies to determine the inhibitory effectiveness of the compounds were carried out on samples of 17G1S steel, which is currently widely used in the construction of gas and oil pipelines.

 As model medium corrosion (CS), we used the installation medium of 200 Tengiz GPZ, composition, g / l: mineralization 1; hydrogen sulfide 3.4; hydrocarbons (kerosene) 100.

 The protective effect against CMR of low alloy steels was determined in accordance with RD 39-0147103-324-88 "Methodology for determining the degree of protection of steel by inhibitors against corrosion-mechanical damage in hydrogen sulfide-containing mineralized media."

 The effectiveness of protection against general corrosion (OK) was evaluated by polarization curves as follows.

и неингибированной

КС.By extrapolating the tafel sections of the anodic and cathodic polarization curves to the value of the corrosion potential, the value of the corrosion current in a hydrogen sulfide corrosion medium (CS) was obtained. Comparing the course of polarization curves in inhibited and non-inhibited CS, the values of corrosion currents in inhibited

and uninhibited

The cop.

Данные измерений приведены в табл. 1, причем каждое значение получено как среднее арифметическое из пяти опытов.The degree of protection against OK is determined by the formula

The measurement data are given in table. 1, with each value obtained as the arithmetic mean of five experiments.

Further, according to GOST 1493-83 (sample type N 4, size 7), samples of steel 17 G1C are tested on an MP-8V tensile testing machine in air, in a NACE model medium and in a model medium with the addition of an inhibitor. To test the samples in the COP, a special corrosion-proof sealed cell was used. The deformation rate of the samples is 7.2 • 10 ^-8 m / s, this speed is chosen in order to increase the contact of steel with Ks. Then determine the coefficient of influence of the CS environment on the relative narrowing of the samples at rupture ψ. The parameter j most fully reflects the ductility margin of steel, which sharply decreases during its corrosion in hydrogen sulfide-containing media, i.e., it is an indicator of SR of the main cause of CMR.

 In the table. Figure 2 shows the test results by definition and Kc, with each value obtained as the arithmetic mean of five parallel experiments.

где ψ_в относительное сужение образцов на воздухе;
ψ_N относительное сужение образцов в КС.Coefficient of influence of Kc on j

where ψ _{is the} relative narrowing of the samples in air;
ψ _{N is the} relative narrowing of the samples in the CS.

где ψ_N+H относительное сужение образца в КС при добавлении ингибитора. ///2 Степень защиты от СР определяют по формуле

При степени защиты от СР более 90 переходят к следующему этапу - испытаниям на коррозионную стойкость.Similarly, the coefficient of influence of KS when adding an inhibitor is calculated

where ψ _{N + H is the} relative narrowing of the sample in the CS with the addition of an inhibitor. /// 2 The degree of protection against CP is determined by the formula

With a degree of protection against CP more than 90, they proceed to the next stage - corrosion tests.

 The protective effect against corrosion fatigue (KU), i.e., the destruction that occurs when a combined cyclic alternating voltage is applied to low alloy steel, which gas and oil pipelines are subject to due to the influence of operational factors, is determined as follows. On a special fatigue machine, flat specimens of steel 17G1S are subjected to cantilever bending with a magnitude of elastoplastic deformation of 2ε 0.74 at a loading frequency of 0.6 Hz, which corresponds to actual operating conditions.

Loading is carried out in air, as well as in a special sealed overhead cell in the COP and in the COP with the addition of an inhibitor. In this case, the number of cycles to complete destruction is determined
In the table. Figure 3 shows the results of these measurements, with each measurement obtained as the arithmetic mean of five parallel experiments.

где N_B число циклов до разрушения на воздухе;
N_N число циклов до разрушения в КС;
N_N+H число циклов до разрушения в КС при добавлении ингибитора.The coefficient of influence of KS on the fatigue life of low alloy steel in KS without inhibitor and in its presence is determined by the formula

where N _{B the} number of cycles to failure in air;
N _{N the} number of cycles to failure in the COP;
N _{N + H the} number of cycles to failure in the COP with the addition of an inhibitor.

Из табл. 1 3 видно, что предлагаемый ингибитор "Реакор-1" обладает высокой степенью защиты как от общей коррозии, так и от сероводородного растрескивания и коррозионной усталости стали в примененной коррозионной среде. Использование предлагаемого ингибитора позволит защищать оборудование не только от сероводородной коррозии, но и от коррозионно-механического разрушения.The degree of protection against KU is calculated by the formula

From the table. 1 3 it is seen that the proposed inhibitor "Reactor-1" has a high degree of protection against general corrosion, and from hydrogen sulfide cracking and corrosion fatigue of steel in the applied corrosive environment. The use of the proposed inhibitor will protect the equipment not only from hydrogen sulfide corrosion, but also from mechanical corrosion damage.

Claims (1)

An inhibitor in hydrogen sulfide-containing mineralized media containing a nitrogen-containing substance, a nonionic surfactant and a hydrocarbon solvent, characterized in that it contains alkylimidazoline as a nitrogen-containing substance and toluene as a hydrocarbon solvent and additionally contains a pyran fraction in the following ratio of components:
Piran fraction 55 95
Alkylimidazoline 3.5 7.0
Nonionic surfactant 0.5 3.0
Toluene Rest

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