RU2663790C1 - Use of n,n-dimethyl-para-anisidine as a corrosion inhibitor in hydrocarbon fuel - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to protection of metals from corrosion in oil and gas industry in production, storage and transportation of hydrocarbons and can be used to protect parts of engines operating on hydrocarbon fuel from the negative effects of water and other impurities, factors that increase their corrosive activity. Use of N,N-dimethyl-para-anisidine as a corrosion inhibitor in hydrocarbon fuels.

EFFECT: use of N,N-dimethyl-para-anisidine as a corrosion inhibitor contributes to increase in corrosive properties of the fuel.

7 cl, 7 tbl

Description

FIELD OF TECHNOLOGY

The invention relates to the field of protection of metals from corrosion in the oil and gas industry during the production, storage and transportation of hydrocarbons and can be used to protect parts of engines running on hydrocarbon fuel from the negative effects of water and other impurities, factors that increase their corrosion activity. The invention is directed to a wide range of applications and, in particular, to ensuring the quality of gasolines, gasolines containing oxygenates, including bioethanol.

BACKGROUND

The relevance in corrosion inhibitors arises during the transfer of fuels through pipelines, during its long-term storage in automobile tanks or metal containers, as well as during significant watering, for example, on ships of the sea and river fleet. The corrosive effect of fuels on metals leads to fouling of fuels with corrosion products in the form of mechanical impurities that impair the pumpability of the fuels and their anti-wear properties. [A.M. Danilov. The use of additives in fuels. - M .: Mir, 2005 .-- 288 p., Ill. ISBN 5-03-003726-8].

The problem of corrosive activity of fuels is aggravated with the introduction of oxygenates (esters, alcohols) in the composition of hydrocarbon fuels, in which water is well soluble, therefore they are a source of its increased content in fuels. In addition, biocomponents (ethanol, methanol, biodiesel), the production of which is actively developing from renewable sources of raw materials, have low stability and a changing composition of impurities, are also a source of increased corrosion activity.

A large number of corrosion inhibitors are known, among which, in the field of hydrocarbon fuels, nitrogen-containing organic compounds C4-C10 alkylamines, polyamines, imidazolines, anilines are used [A. Altsybeeva, S. Levin. Metal corrosion inhibitors. / Ed. L.I. Antropova, L. Chemistry, 1968, p. 7-12, 95, 130, 187].

The disadvantages of the known functional substances are foaming, a tendency to gum formation, poor compatibility and low stability, and the known aniline inhibitors also have extremely low efficiency even at high concentrations of 0.5% due to poor sorption ability to metals.

Known corrosion inhibitors in the composition of multifunctional additives for gasoline (RU 616624 C1, publ. 03/17/2016, prototype) consisting of derivatives of polyisobutenyl succinic anhydride obtained by the interaction of polyisobutenes or polyisobutenes with mol. weight from 300 to 5000, with maleic anhydride, and / or amino, and / or amido, and / or imido groups obtained by reacting said anhydride with aliphatic polyamines, such as ethylene diamine, diethylene triamine, triethylenetetramine or tetraethylene pentamine, isomers and homologs aromatic hydrocarbons, the boiling point is not less than 160 ° C, the temperature of the end of boiling is not more than 200 ° C, at least 90 wt. %), polyester based on propylene oxide and glycerol with a molar mass of 500, polymethylsiloxane.

The disadvantages of the inhibitor developed by the authors are: a large number of components, which does not guarantee the stability of the content of components, impurities and the associated problems with reproducibility of results. In addition, the authors in their work show the effect of the additive on the increase in deposits on the valves, even when they contain detergent components.

An analysis of recent studies in the field of inhibition of corrosion activity shows that their main part is aimed at the use, as active substances, of well-known amides, imidazolines and mixtures thereof.

The experience of their industrial application has revealed a number of systemic problems:

- The instability of these compounds during storage (the occurrence of hydrolysis and condensation reactions in the finished products, leading to a decrease in quality);

- When inhibitors are stored, precipitates form, product stratification and deterioration of solubility are observed;

- Due to the peculiarities of the production of inhibitors and the instability of the quality of the feedstock, different batches of industrial inhibitors have different efficiencies;

- Due to the peculiarities of the properties of substances, the inhibitor supply pipelines become clogged, as well as resinous deposits are formed.

- Modern developments of new corrosion inhibitors are carried out mainly in the field of combining effects or synergies, reducing negative factors, as well as selecting solvents, in order to improve compatibility and ensure the necessary operational characteristics.

Thus, the corrosion inhibitors used have significant drawbacks and the development of new, more effective and safe ones is an important task.

It is known that N-methyl-para-anisidine (NMPA) is actively used as a multifunctional, octane-increasing additive to gasolines [EP 2014643 dated 08/14/2006], and also as an antioxidant of hydrocarbon fuels [RU 2491324 from 01.25.2012, CN 2281460 from 02/21/2012].

NMPA production. Disclosed in RU 2508288 from 09/28/2011 and RU 2632813 from 09/07/2016, involves the formation of an impurity of N, N-dimethyl-para-anisidine (NNDMPA) in small quantities, therefore, the question of its scope is also an urgent task.

The discovery of high sorption activity to metals, as well as the high inhibitory ability of NNDMPA, is an unexpected and not obvious property in view of the fact that the nearest homologues do not have such activity. Most likely, it is the presence of an ester (-methoxy) group in the para position that, as a result of electron-donating interaction with a monomethyl-substituted imino group, changes the property of the compound, providing its sorption activity to metals.

SUMMARY OF THE INVENTION

The objective of the claimed invention is the development of a corrosion inhibitor that provides high anti-corrosion properties of hydrocarbon fuels.

The technical result of the invention is to increase the corrosion properties of the fuel.

The specified technical result is achieved due to the fact that NNDMPA is used as a corrosion inhibitor in hydrocarbon fuels. Gasoline is used as hydrocarbon fuel.

The corrosion inhibitor is administered in an amount of 0.001-1 wt. % in relation to hydrocarbon fuel.

As a hydrocarbon fuel, gasoline containing oxygenates and / or bioethanol is used.

A corrosion inhibitor is introduced into gasoline.

A corrosion inhibitor is incorporated into oxygenates and / or bioethanol.

The corrosion inhibitor is administered in an amount of 0.001-1 wt. % with respect to gasoline or to gasoline containing oxygenates and / or bioethanol.

The effective concentration of the corrosion inhibitor is in the range of 0.001-1 wt. % in relation to hydrocarbon fuel.

DETAILED DESCRIPTION OF THE INVENTION

To use NNDMPA as a corrosion inhibitor in hydrocarbon fuel, the hydrocarbon fuel is mixed with NNDMPA. As hydrocarbon fuels, gasoline, gasoline containing oxygenates and / or bioethanol, diesel fuel, marine fuel, kerosene and other types of hydrocarbon fuels with corrosive activity are used.

To obtain gasoline with a corrosion inhibitor, NNDMPA is added to gasoline in an amount of 0.001-1 wt. % and mixing gasoline with NNDMPA to obtain a homogeneous mixture. Other hydrocarbon fuels containing a corrosion inhibitor are similarly prepared.

To obtain gasoline containing oxygenates with a corrosion inhibitor content of 0.001-1 wt. %., in gasoline add oxygenate containing NNDMPA in an amount of, preferably, from 5 to 15 wt. %, providing the required content of NNDMPA and carry out mixing until a homogeneous mixture. As the oxygenate, for example, methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), ethyl acetate and other esters, as well as isopropyl, butyl and other alcohols can be used.

To obtain gasoline containing bioethanol containing a corrosion inhibitor of 0.001-1 wt. %., bioethanol containing NNDMPA is added to gasoline in an amount of, preferably, from 5 to 15 wt. %, providing the required content of NNDMPA and carry out mixing until a homogeneous mixture.

The study of the corrosion properties of fuels was carried out in accordance with GOST 6321-92 (ISO 2160-85).

The method according to GOST 6321-92 (ISO 2160-85) consists in keeping the copper plate for 3 hours in the test fuel at an elevated temperature (50 ° C) and fixing the change in its appearance characterizing the corrosive effect.

The study of the corrosion properties of fuels according to GOST 6321-92 (ISO 2160-85) was carried out as follows: 30 cm ^{3 of} gasoline with and without an inhibitor, placed in a chemically clean dry tube and introduced there (no more than 1 min after completion of the final polishing) copper plate.

The tube is closed with a stopper with a hole and placed in a bath, where it is kept at a temperature of 50 ° C. During the test, the contents of the tube are protected from exposure to strong light. After 3 hours, the plate is examined, for which it is removed with stainless steel tweezers and immersed in a solvent.

Then the plate is removed, dried with an ashless filter (wet, but not wiped) and check for tarnishing or corrosion, comparing with standards to determine the degree of corrosion. The test plate and standards are held in such a way that the light reflected from them is at an angle of approximately 45 °.

Corrosion activity of the sample is expressed depending on the appearance of the test plate, which coincides with one of the corrosion standards (see table. 5).

The test results are shown in tables 1-4. The use of NNDMPA as an inhibitor in other hydrocarbon fuels not disclosed in tables 1-4

In addition, the corrosion properties (corrosion activity) of gasolines (without inhibitor and with inhibitor) was determined on a steel rod according to the NACE-TM0172-2015 methodology (determination of the corrosion activity of oil products in dynamics).

The study of the corrosive properties of gasolines according to the method of NACE-TM0172-2015 was carried out as follows: 30 ml of distilled water was added to 300 ml of the test fuel with an inhibitor, the cylindrical steel rod was completely immersed in the resulting liquid and kept at 38 ° C for 3.5 hours liquids. Fuel without additives is taken as a reference sample, studies are carried out under the same conditions. After completion of the tests, the tested rod is inspected for the degree and presence of corrosion. The test results are shown in table 6. Classification of the degree of corrosion according to NACE-TM0172-2015 is presented in table 7

Thus, the use of NNDMPA in the claimed invention allows to protect metals (including copper, brass and steel) and exhibiting its activity in a concentration of from 0.001 wt. %, depending on the corrosivity of hydrocarbons and operating conditions. In addition, increased concentrations of NNDMPA up to 1 wt. % do not impair effectiveness. Given the lack of influence of NNDMPA in concentrations from 0.001-1 wt. %, on deposits and the absence of deterioration of other characteristics of gasolines, its use as a corrosion inhibitor does not require accurate dosing, which facilitates applicability.

The use of NNDMPA in gasolines will make it possible to abandon inhibitors that have significant shortcomings and a negative effect on engine deposits and operation, as well as reduce the number of additives due to its multifunctionality.

The invention has been disclosed above with reference to a specific embodiment. Other specialists may be obvious to other embodiments of the invention, without changing its essence, as it is disclosed in the present description. Accordingly, the invention should be considered limited in scope only by the following claims.

(1) - The view of the plate after testing gasolines with the corrosion inhibitor N, N-dimethyl-para-anisidine is light orange, almost the same color as the freshly sanded plate.

(2) - The standards of corrosion are made of plates corresponding to these descriptions.

(3) - A freshly sanded plate is included in the set of standards in order to present the appearance of the sanded plate before the start of the test. Reproduction of the appearance even in the presence of a sample that does not have corrosive activity is not possible.

Claims (7)

1. The use of N, N-dimethyl-para-anisidine as a corrosion inhibitor in hydrocarbon fuels. 2. The use according to claim 1, characterized in that the hydrocarbon fuel in the form of gasoline is used. 3. The use according to claim 2, characterized in that gasoline containing oxygenates and / or bioethanol is used. 4. The use according to claim 3, characterized in that the corrosion inhibitor is introduced into the composition of oxygenates and / or bioethanol. 5. The use according to claim 2, characterized in that the corrosion inhibitor is introduced into the composition of gasoline. 6. The use according to claim 4 or 5, characterized in that the corrosion inhibitor is administered in an amount of 0.001-1 wt. % with respect to gasoline or to gasoline containing oxygenates and / or bioethanol. 7. The use according to claim 1, characterized in that a concentration inhibitor of 0.001-1 wt. % in relation to hydrocarbon fuel.