RU2812141C1 - Method for reducing or preventing corrosion or pollution caused by acid compounds - Google Patents

Abstract

FIELD: corrosion protection.

SUBSTANCE: invention relates to the field of corrosion protection of metallic materials. A method for combating corrosion caused by acidic compounds in a chemical process apparatus being a petroleum refining process, a petrochemical process or a steam generating process, which includes adding to the chemical process apparatus at least one quaternary ammonium hydroxide of formula (I):

in which R¹, R², R³ are all independently C₁-C₆-alkyl; R⁴ is C₂-C₁₈-alkyl; R³ and R⁴ together with a nitrogen atom can also form a 5 or 6 membered saturated nitrogen atom containing heterocycle which is unsubstituted or contains 1 or 2 methyl groups.

EFFECT: reducing or preventing corrosion or contamination in an apparatus intended for carrying out a chemical process in which corrosion or contamination is caused by acidic compounds.

16 cl, 1 dwg, 12 tbl, 11 ex

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

The present invention relates to a method for reducing or preventing corrosion or contamination that is caused by acidic compounds, such as acids, such as hydrogen chloride, or acid ammonium salts, such as ammonium chloride, which are contained or generated during a chemical process, such as a petrochemical process. The method includes the step of adding at least one quaternary ammonium hydroxide according to the present invention to an apparatus that is used to carry out a chemical process.

BACKGROUND OF THE ART

Corrosion and contamination are serious problems encountered in chemical processing equipment, especially in crude oil processing plants such as refineries and petrochemical plants, as they lead to disruption of the process equipment and therefore economic losses, as well as harmful effects on the environment and health. The main cause of corrosion and contamination are ammonium salts, such as organic and inorganic ammonium halides, ammonium sulfate or ammonium hydrogen sulfate, since they, in gaseous, liquid or solid form, are corrosive and can also contribute to the formation of deposits that can cause damage. hydraulic or thermal conditions in various system components. Ammonium salts typically enter a process system as a component of a feedstock such as crude oil, but they can also be formed during a chemical process. In addition, corrosion in oil refineries and petrochemical plants, as well as in other chemical equipment, can occur due to the presence of acidic compounds, such as, in particular, hydrogen chloride, which are formed during the process. Thus, for example, in a crude oil distillation module, hydrogen chloride may be formed due to the hydrolysis of calcium chloride or magnesium chloride still contained in the desalted crude oil that is charged to the module.

US 7,279,089 and US 8,177,962 describe methods for preventing corrosion and fouling in a petrochemical process by neutralizing acidic compounds such as ammonium chloride or hydrogen chloride using choline hydroxide, which is added to appropriate process modules. Choline hydroxide has been described to have more favorable characteristics than ammonia and other amines commonly used for such purposes. First, choline hydroxide is more basic and can therefore be added at lower molar levels and provide more effective pH control. In addition, due to the higher basicity of choline hydroxide, it reacts with acidic compounds to form salts, aqueous solutions of which have higher pH values. This significantly reduces the risk of secondary corrosion caused by salts formed during neutralization. In addition, these neutralization products formed with choline hydroxide are extremely hygroscopic, they are able to absorb even trace amounts of moisture and easily form fluid solutions, this ensures easy removal of salts from process streams.

However, there are also some disadvantages to using choline hydroxide to reduce fouling and corrosion. Firstly, aqueous solutions of choline hydroxide have limited thermal stability at temperatures exceeding 180°C, and, in addition, during long-term storage they acquire an unpleasant odor and change color.

Despite the advances that have been made in the field of preventing and eliminating corrosion and contamination, there is still a continuing need to develop an effective and economical way to control corrosion and contamination in chemical processes, especially in chemical processes that use high temperature. It is therefore an object of the present invention to provide a method which, in particular, has all the advantages of the prior art procedures described above, which use choline hydroxide to reduce corrosion and contamination, and which also eliminates the disadvantages of these procedures. Thus, the corrosion and fouling reducing or preventing compound used in this method, as well as its aqueous solutions, must have sufficient thermal and storage stability and, in particular, must remain stable at temperatures significantly above 180°C without significant leakage. decomposition. Such temperatures are prevalent, for example, in some liquid or gaseous streams used in petroleum refining systems or petrochemical systems such as hydrodesulfurization units. In addition, said compound should have improved basicity and ammonium salt dissolving ability superior to that of choline hydroxide.

This problem is solved using a method described in detail below.

SUMMARY OF THE INVENTION The present invention relates to a method for reducing or preventing corrosion or contamination in a chemical process apparatus, where the corrosion or contamination is caused by acidic compounds contained in the chemical process, which includes adding to the chemical process apparatus, at least one quaternary ammonium hydroxide of formula (I):

wherein

R ¹ , R ² , R ³ are all independently C ₁ -C ₁₀ -alkyl;

R ⁴ is selected from the group consisting of the following: C ₁ -C ₁₈ -alkyl, benzyl, monocycloalkyl containing 5, 6, 7 or 8 carbon atoms, bicycloalkyl containing from 6 to 8 carbon atoms, tricycloalkyl containing from 7 to 10 carbon atoms, where monocycloalkyl, bicycloalkyl and tricycloalkyl are unsubstituted or substituted with 1 or 2 methyl groups, and groups of the formulas R ^4a and R ^4b ;

Where

A is C ₂ -C ₈ -alkanediyl;

A' is C ₂ -C ₈ -alkanediyl; And

R ¹¹ , R ¹² , R ¹³ , R ²¹ , R ²² are all independently C ₁ -C ₄ -alkyl;

R ¹ and R ² together with a nitrogen atom can also form a 5 or 6 membered saturated nitrogen atom containing heterocycle, which is unsubstituted or contains 1 or 2 methyl groups; and/or

R ³ and R ⁴ together with a nitrogen atom can also form a 5 or 6 membered saturated nitrogen atom containing heterocycle which is unsubstituted or contains 1 or 2 methyl groups.

The present invention also relates to the use of quaternary ammonium hydroxide of formula (I) for reducing or preventing corrosion or fouling in a chemical process apparatus where the corrosion or fouling is caused by acidic compounds contained in the chemical process.

DETAILED DESCRIPTION OF THE INVENTION

In the context of the present invention, the terms and expressions used in the present invention are generally defined below:

The prefix "C _x -C _y " means the number of carbon atoms possible in a particular case.

The term "C ₁ -C ₁₈ -alkyl" as used in the present invention means saturated straight-chain or branched hydrocarbon radicals containing from 1 to 4 ("C ₁ -C ₄ -alkyl"), from 1 to 6 ("C ₁ -C ₆ -alkyl"), from 1 to 10 ("C ₁ -C ₁₀ -alkyl") or from 1 to 18 ("C ₁ -C ₁₈ -alkyl") carbon atoms. C ₁ -C ₄ -Alkyl means methyl, ethyl, n-propyl, isopropyl, n-butyl, 1-methyl-n-propyl (sec-butyl), 2-methyl-n-propyl (isobutyl) or 1,1- dimethylethyl (tert-butyl). C ₁ -C ₆ -Alkyl further means, for example, n-pentyl, 1-methyl-n-butyl, 2-methyl-n-butyl, 3-methyl-n-butyl, 2,2-dimethyl-n-propyl, 1-ethyl-n-propyl, 1,1-dimethyl-n-propyl, 1,2-dimethyl-n-propyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 3- methyl-n-pentyl, 4-methyl-n-pentyl, 1,1-dimethyl-n-butyl, 1,2-dimethyl-n-butyl, 1,3-dimethyl-n-butyl, 2,2-dimethyl- n-butyl, 2,3-dimethyl-n-butyl, 3,3-dimethyl-n-butyl, 1-ethyl-n-butyl, 2-ethyl-n-butyl, 1,1,2-trimethyl-n- propyl, 1,2,2-trimethyl-n-propyl, 1-ethyl-1-methyl-n-propyl or 1-ethyl-2-methyl-n-propyl. C ₁ -C ₁₀ -Alkyl also further means, for example, n-heptyl, n-octyl, 2-ethyl-n-hexyl, n-nonyl, n-decyl and positional isomers thereof. C ₁ -C ₁₀ -Alkyl also further means, for example, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl and positional isomers thereof.

The term "monocycloalkyl containing 5, 6, 7 or 8 carbon atoms" as used in the present invention means monocyclic C ₅ -C ₈ -cycloalkyl radicals, namely, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl.

The term "bicycloalkyl containing from 6 to 8 carbon atoms" as used in the present invention means a bridged alicyclic C ₆ -C ₈ -hydrocarbyl radical containing 2 bridged carbon atoms. Examples include, but are not limited to, bicyclo[2.1.1]hexyl, bicyclo[2.2.1]heptyl, which is also known as norbornyl, bicyclo[3.2.0]heptyl, bicyclo[4.1.0]heptyl, bicyclo[ 3.2.1]octyl and bicyclo[2.2.2]octyl.

The term "tricycloalkyl containing from 7 to 10 carbon atoms" as used in the present invention means a bridged alicyclic C ₇ -C ₁₀ -hydrocarbyl group containing 4 bridged carbon atoms, each of which is common to three rings. Examples include, but are not limited to, tricyclo[3.3.1.1 ^3,7 ]decanyl and tricyclo[5.2.1.0 ^2,6 ]decanyl, which are also known as adamantyl and tetrahydrodicyclopentadienyl, respectively.

The term "C ₂ -C ₈ -alkanediyl" as used in the present invention means a divalent saturated aliphatic hydrocarbon radical containing from 2 to 8 carbon atoms. Examples of C ₂ -C ₈ -alkanediyl are, in particular, linear alkanediyl such as 1,2-ethanediyl, 1,3-n-propanediyl, 1,4-n-butanediyl, 1,5-n-pentanediyl, 1, 6-n-hexanediyl, 1,7-n-heptanediyl and 1,8-n-octanediyl, as well as branched alkanediyl such as 1-methyl-1,2-ethanediyl, 1-methyl-1,2-n-propanediyl , 2-methyl-1,3-n-butanediyl, 1,3-n-pentanediyl, 2-ethyl-1,6-n-hexanediyl, etc.

The term "5- or 6-membered saturated nitrogen atom-containing heterocycle" as used in the present invention means a saturated monocyclic ring containing as a ring element one nitrogen atom, namely, pyrrolidinyl and piperidinyl.

The term "crude oil processing plants" includes plants that process crude oil, such as refineries and petrochemical plants, and plants that integrate refinery processes and petrochemical processes into one system.

In formula (I), the variables R ¹ , R ² , R ³ , R ⁴ , R ^4a , R ^4b , R ¹¹ , R ¹² , R ¹³ , R ²¹ , R ²² , A and A' individually or in any combination are preferred have the following meanings:

Regardless of when they are indicated, the variables R ¹ , R ² and R ³ are the same or different and are preferably selected from C ₁ -C ₆ alkyls, especially preferably selected from C ₁ -C ₄ -alkyls, i.e. from the group consisting of the following: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl. It is particularly preferred that R ¹ , R ² and R ³ are the same or different and are selected from the group consisting of methyl, ethyl, n-propyl and n-butyl.

Alternatively, the variables R ¹ and R ² together with the nitrogen atom to which they are attached may preferably form a 5 or 6 membered saturated nitrogen atom containing heterocycle which contains one methyl group or is preferably unsubstituted, R ³ and R ⁴ being such , as defined in the present invention, and preferably have the meanings indicated as preferred.

Regardless of the case in which they are specified, the variables R ¹¹ , R ¹² , R ¹³ , R ²¹ and R ²² , when contained in the quaternary ammonium hydroxide of formula (I), are the same or different and are preferably selected from C ₁ -C ₄ -alkyls, i.e. from the group consisting of the following: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl and isobutyl, more preferably from the group consisting of the following: methyl, ethyl, n-propyl and n-butyl, and especially preferably from the group consisting of the following: methyl and ethyl. Particularly preferred R ¹¹ , R ¹² , R ¹³ , R ²¹ and R ²² , when present, are all methyl.

Variable A preferably represents a linear C ₂ -C ₈ alkanediyl diradical and more preferably a linear C ₂ -C ₆ alkanediyl diradical. It is especially preferred if the variable A is hexanediyl.

The variable A' preferably represents a linear C ₂ -C ₈ alkanediyl diradical and more preferably a linear C ₂ -C ₆ alkanediyl diradical.

The variable R ^4a is selected from the group consisting of the following: hydroxides of 2-(trimethylammonium)ethyl, 3-(trimethylammonium)-n-propyl, 4-(trimethylammonium)-n-butyl, 5-(trimethylammonium)-n-pentyl and 6 -(trimethylammonium)-n-hexyl, and is preferably 6-(trimethylammonium)-n-hexyl hydroxide.

The R ^4b variable is selected from the group consisting of the following: 2-(trimethylammonium)ethyl-(dimethylammonium)ethyl dihydroxides, 3-(trimethylammonium)-n-prop-1-yl-(dimethylammonium)-n-propyl dihydroxides, 4-(trimethylammonium )-n-but-1-yl-(dimethylammonium)-n-butyl, 5-(trimethylammonium)-n-pent-1-(dimethylammonium)-n-pentyl and 6-(trimethylammonium)-n-hex-1- yl-(dimethylammonium)-n-hexyl.

Preferably, the R ⁴ variable is selected from the group consisting of the following: C ₁ -C ₁₀ -alkyl, benzyl, cyclopentyl, cyclohexyl, bicycloalkyl containing 7 or 8 carbon atoms, tricycloalkyl containing 9 or 10 carbon atoms, where monocycloalkyl, bicycloalkyl and tricycloalkyl are unsubstituted or substituted with 1 or 2 methyl groups, and groups of the formula R ^4a , wherein the variables R ¹¹ , R ¹² , R ¹³ and A in the formula R ^4a have the meanings defined in the present invention, in particular the preferred meanings. More preferably, R ⁴ is selected from the group consisting of the following: C ₁ -C ₄ -alkyl, benzyl, cyclopentyl, cyclohexyl, norbornyl, 7,7-dimethylnorbornyl, bicyclo[3.2.0]heptyl, bicyclo[4.1.0] heptyl, bicyclo[3.2.1]octyl, bicyclo[2.2.2]octyl, adamantyl, 1-methyladamantyl, 1,3-dimethyladamantyl, tetrahydrodicyclopentadienyl and 6-(trimethylammonium)hexyl hydroxide. It is particularly preferred if R ⁴ is selected from the group consisting of the following: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, benzyl, cyclopentyl, cyclohexyl, norbornyl, adamantyl and 6-(trimethylammonium) hydroxide hexyl, and is especially preferably selected from the group consisting of the following: methyl, ethyl, n-propyl, n-butyl, benzyl, adamantyl and 6-(trimethylammonium)hexyl hydroxide.

Alternatively, the variables R ³ and R ⁴ together with the nitrogen atom to which they are attached may preferably form a 5 or 6 membered saturated nitrogen atom containing heterocycle that contains one methyl group or is preferably unsubstituted, R ¹ and R being such that as defined in the present invention, and preferably have the meanings indicated as preferred.

In one preferred group of embodiments, in the quaternary ammonium hydroxide of formula (I), the variables R ¹ , R ² , R ³ and R ⁴ are defined as follows:

R ¹ , R ² and are the same or different and are preferably selected from C ₁ -C ₆ alkyls, especially preferably selected from C ₁ -C ₄ alkyls, i.e. from the group consisting of the following: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl. It is particularly preferred if R ¹ , R ² and R ³ are the same or different and are selected from the group consisting of the following: methyl, ethyl, n-propyl and n-butyl; R ⁴ is selected from the group consisting of the following: C ₁ -C ₁₀ -alkyl, benzyl, cyclopentyl, cyclohexyl, bicycloalkyl containing 7 or 8 carbon atoms, tricycloalkyl containing 9 or 10 carbon atoms, where monocycloalkyl, bicycloalkyl and tricycloalkyl are unsubstituted or substituted with 1 or 2 methyl groups, and groups of the formula R ^4a , wherein the variables R ¹¹ , R ¹² , R ¹³ and A in the formula R ^4a have the meanings defined in the present invention, in particular the preferred meanings. More preferably, R ⁴ is selected from the group consisting of the following: C ₁ -C ₄ -alkyl, benzyl, cyclopentyl, cyclohexyl, norbornyl, 7,7-dimethylnorbornyl, bicyclo[3.2.0]heptyl, bicyclo[4.1.0] heptyl, bicyclo[3.2.1]octyl, bicyclo[2.2.2]octyl, adamantyl, 1-methyladamantyl, 1,3-dimethyladamantyl, tetrahydrodicyclopentadienyl, and 6-(trimethylammonium)hexyl hydroxide. It is especially preferred if R ⁴ is selected from the group consisting of the following: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, benzyl, cyclopentyl, cyclohexyl, norbornyl, adamantyl and 6-(trimethylammonium) hydroxide hexyl, and is particularly preferably selected from the group consisting of methyl, ethyl, n-propyl, n-butyl, benzyl, adamantyl, and 6-(trimethylammonium)hexyl hydroxide.

In another preferred group of embodiments, in the quaternary ammonium hydroxide of formula (I), the variables R ¹ , R ² , R ³ and R ⁴ are defined as follows:

R ¹ and R ² together with the nitrogen atom to which they are attached form a 5 or 6 membered saturated nitrogen atom containing heterocycle which contains one methyl group or is preferably unsubstituted, R is selected from C ₁ -C ₆ -alkyl, preferably , if it is selected from among C ₁ -C ₄ alkyls, i.e. from the group consisting of the following: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl. It is particularly preferred if R ³ is selected from the group consisting of methyl, ethyl, n-propyl and n-butyl.

R ⁴ is selected from the group consisting of the following: C ₁ -C ₁₀ -alkyl, benzyl, cyclopentyl, cyclohexyl, bicycloalkyl containing 7 or 8 carbon atoms, tricycloalkyl containing 9 or 10 carbon atoms, where monocycloalkyl, bicycloalkyl and tricycloalkyl are unsubstituted or substituted with 1 or 2 methyl groups, and groups of the formula R ^4a , wherein the variables R ¹¹ , R ¹² , R ¹³ and A in the formula R ^4a have the meanings defined in the present invention, in particular the preferred meanings. More preferably, R ⁴ is selected from the group consisting of the following: C ₁ -C ₄ -alkyl, benzyl, cyclopentyl, cyclohexyl, norbornyl, 7,7-dimethylnorbornyl, bicyclo[3.2.0]heptyl, bicyclo[4.1.0] heptyl, bicyclo[3.2.1]octyl, bicyclo[2.2.2]octyl, adamantyl, 1-methyladamantyl, 1,3-dimethyladamantyl, tetrahydrodicyclopentadienyl and 6-(trimethylammonium)hexyl hydroxide. It is particularly preferred if R ⁴ is selected from the group consisting of the following: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, benzyl, cyclopentyl, cyclohexyl, norbornyl, adamantyl and 6-(trimethylammonium) hydroxide hexyl, and is particularly preferably selected from the group consisting of methyl, ethyl, n-propyl, n-butyl, benzyl, adamantyl, and 6-(trimethylammonium)hexyl hydroxide.

In another preferred group of embodiments, in the quaternary ammonium hydroxide of formula (I), the variables R ¹ , R ² , R ³ and R ⁴ are defined as follows:

R ¹ and R ² together with the nitrogen atom to which they are attached form a 5 or 6 membered saturated nitrogen atom containing heterocycle which contains one methyl group or is preferably unsubstituted, R ³ and R ⁴ together with the nitrogen atom to which they are attached attached to form a 5 or 6 membered saturated nitrogen containing heterocycle which contains one methyl group or is preferably unsubstituted.

In a particularly preferred group of embodiments, R ¹ , R ² , R ³ are all independently C ₁ -C ₆ alkyl, preferably they are all independently C ₁ -C ₄ alkyl, and particularly preferably they are independently selected from the following: methyl, ethyl, n-propyl and n-butyl; and R ⁴ is C ₁ -C ₁₈ -alkyl, benzyl, cyclopentyl, cyclohexyl, C ₇ -C ₈ -bicycloalkyl, C ₉ -C ₁₀ -tricycloalkyl or 6-(trimethylammonium)hexyl hydroxide, preferably when it is C ₂ - C ₁₀ -alkyl, benzyl, norbornyl, adamantyl or 6-(trimethylammonium)hexyl hydroxide.

In another particularly preferred group of embodiments, R ¹ and R ² together with the nitrogen atom to which they are attached form a 5 or 6 membered saturated nitrogen atom containing heterocycle that is unsubstituted or contains 1 or 2 methyl groups, preferably if they form a 5 or 6 membered saturated nitrogen containing heterocycle which is unsubstituted, and particularly preferably they form an unsubstituted pyrrolidinium ring;

R ³ is C ₁ -C ₆ -alkyl, preferably each is independently C ₁ -C ₄ -alkyl, and particularly preferably each is independently selected from the group consisting of methyl, ethyl, n-propyl and n- butyl; and R ⁴ is C ₁ -C ₁₈ -alkyl, benzyl, cyclopentyl, cyclohexyl, C ₇ -C ₈ -bicycloalkyl, C ₉ -C ₁₀ -tricycloalkyl or 6-(trimethylammonium)hexyl hydroxide, and is preferably C ₂ -C ₁₀ -alkyl, benzyl, norbornyl, adamantyl or 6-(trimethylammonium)hexyl hydroxide.

In yet another particularly preferred group of embodiments, R ¹ and R ² together with the nitrogen atom to which they are attached form a 5 or 6 membered saturated nitrogen atom containing heterocycle that is unsubstituted or contains 1 or 2 methyl groups, preferably if they form a 5 or 6 membered saturated nitrogen atom-containing heterocycle which is unsubstituted, and particularly preferably they form an unsubstituted pyrrolidinium ring; And

R ³ and R ⁴ together with the nitrogen atom to which they are attached form a 5 or 6 membered saturated nitrogen containing heterocycle that is unsubstituted or contains 1 or 2 methyl groups, preferably they form a 5 or 6 membered saturated nitrogen containing heterocycle a nitrogen atom of a heterocycle that is unsubstituted, and it is particularly preferred that they form an unsubstituted pyrrolidinium ring.

Examples of preferred quaternary ammonium hydroxides of formula (I) corresponding to the above groups of embodiments intended for use in the method proposed in the present invention are selected from the group consisting of the following: cyclopentyltrimethylammonium hydroxide, cyclohexyltrimethylammonium hydroxide, norbornyltrimethylammonium hydroxide, adamantyltrimethylammonium hydroxide, 5- azoniaspiro[4.4]nonane hydroxide, benzyltrimethylammonium hydroxide, diethyldimethylammonium hydroxide, ethyltrimethylammonium hydroxide, dimethyldi-n-propylammonium hydroxide, n-propyltrimethylammonium hydroxide, triethylmethylammonium hydroxide, tetramethylammonium hydroxide, diethyldi-n-propylammonium hydroxide, n-propyl hydroxide triethylammonium, dimethyldi-n-hydroxide butylammonium, n-butyltrimethylammonium hydroxide, n-butyltriethylammonium hydroxide, tetraethylammonium hydroxide, tetra-n-propylammonium hydroxide, tetra-n-butylammonium hydroxide, hexamethonium hydroxide and N,N-dimethylpyrrolidinium hydroxide; preferably they are selected from among the following: adamantyltrimethylammonium hydroxide, 5-azoniaspiro[4.4]nonane hydroxide, benzyltrimethylammonium hydroxide, diethyldimethylammonium hydroxide, ethyltrimethylammonium hydroxide, dimethyldin-n-propylammonium hydroxide, triethylmethylammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide ia, tetra-n-hydroxide propylammonium, tetra-n-butylammonium hydroxide, hexamethonium hydroxide and N,N-dimethylpyrrolidinium hydroxide; and especially preferably they are selected from among the following: adamantyltrimethylammonium hydroxide, 5-azoniaspiro[4.4]nonane hydroxide, benzyltrimethylammonium hydroxide, diethyldimethylammonium hydroxide, ethyltrimethylammonium hydroxide, dimethyldin-n-propylammonium hydroxide, triethylmethylammonium hydroxide, tetraethylammonium hydroxide, tetra-hydroxide n-propylammonium , tetra-n-butylammonium hydroxide, hexamethonium hydroxide and N,N-dimethylpyrrolidinium hydroxide.

In another preferred group of embodiments, in the quaternary ammonium hydroxide of formula (I), the variables R ¹ , R ² , R ³ and R ⁴ are defined as follows:

R ¹ , R ² , R ³ are all independently C ₁ -C ₆ -alkyl, preferably they are all independently C ₁ -C ₄ -alkyl, and especially preferably they are independently selected from the following: methyl, ethyl, n-propyl and n-butyl; R ⁴ is C ₁ -C ₁₈ alkyl, preferably C ₂ -C ₁₈ alkyl, particularly preferably C ₂ -C ₄ alkyl, and particularly preferably selected from the following: ethyl , n-propyl and n-butyl;

or alternatively:

R ³ and R ⁴ together with the nitrogen atom to which they are attached form a 5 or 6 membered saturated nitrogen containing heterocycle that is unsubstituted or contains 1 or 2 methyl groups, preferably they form a 5 or 6 membered saturated nitrogen containing heterocycle a nitrogen atom of a heterocycle that is unsubstituted, and it is particularly preferred that they form an unsubstituted pyrrolidinium ring.

Examples of preferred quaternary ammonium hydroxides of formula (I) corresponding to this group of embodiments intended for use in the method proposed in the present invention are selected from the group consisting of the following: diethyldimethylammonium hydroxide, ethyltrimethylammonium hydroxide, dimethyldin-n-propylammonium hydroxide, n -propyltrimethylammonium, triethylmethylammonium hydroxide, tetramethylammonium hydroxide, diethyldi-n-propylammonium hydroxide, n-propyltriethylammonium hydroxide, dimethyldi-n-butylammonium hydroxide, n-butyltrimethylammonium hydroxide, n-butyltriethylammonium hydroxide, tetraethylammonium hydroxide, tetra-n-propylam hydroxide monium hydroxide tetra -n-butylammonium and N,N-dimethylpyrrolidinium hydroxide; and especially preferably they are selected from among the following: diethyldimethylammonium hydroxide, ethyltrimethylammonium hydroxide, dimethyldi-n-propylammonium hydroxide, triethylmethylammonium hydroxide, tetraethylammonium hydroxide, tetra-n-propylammonium hydroxide, tetra-n-butylammonium hydroxide and N,N-dimethylpyrrolidinium hydroxide .

In a particularly preferred group of embodiments, in the quaternary ammonium hydroxide of formula (I), the variables R ¹ , R ² , R ³ and R ⁴ are defined as follows:

R ¹ , R ² , R ³ are all independently C ₁ -C ₆ -alkyl, preferably they are all independently C ₁ -C ₄ -alkyl, and especially preferably they are independently selected from the following: methyl, ethyl, n-propyl and n-butyl; and R ⁴ is C ₂ -C ₆ alkyl, preferably C ₂ -C ₄ alkyl, and particularly preferably selected from ethyl, n-propyl and n-butyl.

Examples of preferred quaternary ammonium hydroxides of formula (I) corresponding to this group of embodiments intended for use in the method proposed in the present invention are selected from the group consisting of the following: diethyldimethylammonium hydroxide, ethyltrimethylammonium hydroxide, dimethyldin-n-propylammonium hydroxide, n -propyltrimethylammonium, triethylmethylammonium hydroxide, diethyldine-n-propylammonium hydroxide, n-propyltriethylammonium hydroxide, dimethyldi-n-butylammonium hydroxide, n-butyltrimethylammonium hydroxide, n-butyltriethylammonium hydroxide, tetraethylammonium hydroxide, tetra-n-propylammonium hydroxide and tetra-n hydroxide - butylammonium; preferably they are selected from among the following: diethyldimethylammonium hydroxide (HDEDMA), ethyltrimethylammonium hydroxide (GETMA), dimethyldi-n-propylammonium hydroxide (DMDPA), triethylmethylammonium hydroxide (GTEMA), tetraethylammonium hydroxide (GTEA), tetra-n-propylammonium hydroxide ( GTPA) and tetra-n-butylammonium hydroxide (HTBA), and are particularly preferably selected from the group consisting of HDEDMA, GTEMA, GTEA, GTPA and GTBA.

It is particularly preferred if at least one quaternary ammonium hydroxide of formula (I) is selected from the group consisting of the following: HDEDMA, GTEMA, GTEA, GTPA and GTBA and mixtures thereof, most preferred being GTEA, as well as mixtures of GTEA with one or more ammonium hydroxides of formula (I), which differ from GTEA, preferably with one or more of the following: HDEDMA, GTEMA, GTPA and GTBA.

The present invention relates to a method for reducing or preventing corrosion or contamination in a chemical process apparatus. In the present invention, corrosion means corrosion damage to metal components that are part of the apparatus, and contamination means the accumulation and formation of deposits of unwanted material on the internal surfaces of the apparatus. Corrosion and contamination are caused by acidic compounds contained during the chemical process.

In the context of the present invention and in the following description, the expression "acidic compounds contained in a chemical process" means the following:

- acidic compounds that are already contained, for example, in the raw materials that are processed during the chemical process, and are thus loaded into the apparatus intended for carrying out the chemical process, and/or

- acidic compounds that are formed only during the process.

To reduce or prevent corrosion or fouling, the method includes adding at least one quaternary ammonium hydroxide of formula (I), preferably at least one ammonium hydroxide of formula (I) specified in the present invention as preferred, to the apparatus in which the chemical process.

Typically, one ammonium hydroxide of formula (I) or a mixture of two or more ammonium hydroxides (I) is added. If such mixtures are used, then preference is given to mixtures containing two or more, especially preferably two or three, ammonium (I) hydroxides indicated in the present invention as preferred, especially preferably selected from among the following: GTEA, GTPA, GTBA, GTEMA and GDEDMA, and particular preference is given to mixtures containing GTEA and GDEDMA, GTEA and GTEMA or GTEA, GDEDMA and GTEMA. However, other mixtures of ammonium hydroxides of formula (I) can also be used in the method of the present invention, for example to control the characteristics of the salts that are formed after the reaction of ammonium hydroxides of formula (I) with acidic compounds contained in the apparatus being treated, such as this described below in the present invention.

In one set of embodiments of the present invention, at least one ammonium (I) hydroxide is added to the liquid or gaseous stream used for the chemical process carried out in the apparatus. In the context of the present invention, ammonium hydroxide of formula (I) is added undiluted or, preferably, in the form of a solution. The addition can be accomplished by adding one or more ammonium hydroxides of formula (I) to the feedstock entering the apparatus, or by adding them at specific positions in the apparatus, which are often located before sections or modules of the apparatus that are, or are likely to be, subject to corrosion or contamination .

With the method proposed in the present invention, it is in principle possible to substantially remove acidic compounds during chemical processes or to substantially prevent their formation during these processes, since the use of at least one quaternary ammonium hydroxide of formula (I) ensures the neutralization of such acidic compounds. compounds and their transformation into the corresponding salts. These salts are generally less likely to contribute to corrosion and fouling than the corresponding acidic compounds.

Examples of acidic compounds that can cause corrosion and/or fouling in chemical process apparatus include, but are not limited to, hydrogen halides such as hydrogen chloride, hydrogen fluoride or hydrogen bromide, especially hydrogen chloride, sulfide hydrogen, hydrogen cyanide, thiocyanic acid, sulfuric acid, SO ₂ , SO ₃ , nitrogen oxides, especially NO and NO ₂ , carbonic acid, CO ₂ , organic acids, especially carboxylic acids and sulfonic acids, acid ammonium salts, acid phosphorus-containing compounds and mixtures thereof. It is known that the above protic acids, as well as protic acids formed from the above oxides, promote the development of corrosion, and can also contribute to the contamination of chemical plants, and ammonium acid salts often cause both corrosion and contamination. More specifically, hydrogen halides, hydrogen sulfide, hydrogen cyanide, thiocyanic acid, organic acids and ammonium acid salts are corrosive and fouling substances that are often contained in petroleum refining processes and petrochemical processes, such as, in particular, petroleum refining processes. Acidic phosphorus-containing compounds can also be found in crude oils such as shale oil. On the other hand, carbonic acid and _CO2 , as well as organic acids, are usually the main corrosive substances found in steam generating equipment, such as boiler systems used in chemical processes, while nitrogen oxides, which are formed, for example, during combustion , cause corrosion in combustion equipment mainly at the outlet of the exhaust gas, for example in diesel engines.

The method of the present invention is particularly suitable for reducing or preventing corrosion caused by acidic compounds, which are selected from the group consisting of the following: hydrogen chloride, hydrogen fluoride, SO ₃ , nitrogen oxides, acid ammonium salts and acid phosphorus compounds. Acid ammonium salts and acid phosphorus-containing compounds may be inorganic or organic compounds. Examples of ammonium acid salts include, but are not limited to, inorganic and organic ammonium halides such as ammonium chloride and N-substituted ammonium chlorides, ammonium fluoride or ammonium bromide, especially ammonium chloride, organic ammonium chlorides such as di- and tri-C ₁ -C ₄ -alkylammonium such as trimethylammonium chloride or triethylammonium chloride, alkylenediamine hydrochlorides such as ethylenediamine monohydrochloride, alkanolamine hydrochlorides such as dimethylethanolammonium chloride, and alkoxyalkylamine hydrochlorides such as 3-methoxypropylammonium chloride, ammonium hydrosulfide, sulphide ammonium ide , ammonium hydrogen sulfate, ammonium sulfate and ammonium salts formed with carboxylic acids containing from 1 to 10 carbon atoms, such as ammonium formate, ammonium acetate, ammonium propionate or ammonium butyrate, in particular ammonium acetate. Acidic phosphorus-containing compounds include, but are not limited to, phosphoric acid, polyphosphoric acid, acid phosphates and acid polyphosphates, phosphonic acid and acid phosphonates. Polyphosphoric acid and acidic polyphosphates contain at least 2, for example, on average from 2 to 1000 P atoms and can be linear, branched or cyclic. Examples of acid phosphates include partial esters of phosphoric acid, and mono- and dihydrogen phosphates of alkali metals or alkaline earth metals. Examples of acid polyphosphates include acid salts of polyphosphoric acid, especially acid polyphosphates of alkali metals or alkaline earth metals.

Particularly characteristic corrosive or fouling acidic compounds are hydrogen chloride, hydrogen fluoride, sulfur trioxide, nitrogen oxides, ammonium chloride, organic ammonium chlorides such as trimethylammonium chloride, triethylammonium chloride, ethylenediamine monohydrochloride, dimethylethanolammonium chloride and 3-methoxypropylammonium chloride, ammonium sulfide, ammonium hydrosulfide, ammonium sulfate and ammonium hydrogen sulfate, and in particular hydrogen chloride, ammonium chloride and organic ammonium chlorides. The method of the present invention is particularly suitable for combating the corrosive and fouling effects of these compounds in chemical process apparatus.

Quaternary ammonium hydroxides of formula (I) used in the method proposed in the present invention are highly soluble in water, as well as in mixtures of water with a C ₁ -C ₄ alkanol, such as methanol, ethanol, propanol or butanol. The authors of the present invention have discovered that aqueous solutions of ammonium (I) hydroxides, in particular solutions having high concentrations of about 10 to 60 wt. % or from 20 to 40 wt. %, are extremely stable during storage, even at elevated temperatures up to 50°C.

The term "aqueous solutions" means solutions of a compound of formula (I) in water or in mixtures of water with one or more water-miscible organic solvents, such as mixtures of water with one or more C ₁ -C ₄ alkanols, where water is the main a component of a mixture of water and an organic solvent, i.e. where the amount of water is at least 50 wt. % based on the total weight of the mixture of water and organic solvent.

Thus, in contrast to the corresponding choline hydroxide solutions, they are highly resistant to color changes or odor development. In fact, after long-term storage at 40° C., solutions of ammonium hydroxides of formula (I) remain clear and colorless and have only a faint odor, while a solution of choline hydroxide turns yellow and acquires an extremely strong fishy odor. Thus, aqueous solutions of ammonium hydroxides of formula (I) have higher storage stability than corresponding solutions of choline hydroxide, and in particular are well suited for long-term storage even under unfavorable storage conditions.

A particular advantage of the present invention is that ammonium hydroxides of formula (I) and their aqueous solutions have good stability at temperatures well above 200°C, i.e. under these conditions, the rate of decomposition of ammonium hydroxides of formula (I) is low. Therefore, ammonium hydroxides of formula (I), in particular aqueous solutions thereof, can be safely added to process streams having temperatures of up to 250°C, since at such temperatures ammonium hydroxides of formula (I) remain unchanged for a long period of time and thus they are able to effectively combat corrosion and contamination. The stability of aqueous solutions of ammonium hydroxides of formula (I) at high temperatures is an extremely advantageous characteristic since they can be added in positions where the temperature is high, such as, for example, feed/effluent heat exchangers used in hydrodesulfurization units, without the occurrence of a significant loss of their anti-corrosion and anti-pollution effectiveness. This is practically impossible or impossible to achieve using choline hydroxide and its solutions, which already undergo significant decomposition at temperatures exceeding 200°C.

In addition, due to the high stability of ammonium hydroxides of formula (I) and their aqueous solutions, they can be added to process streams much earlier than conventional anti-corrosion and fouling agents, and thus reach hard-to-reach areas of apparatus such as technological installations that were previously inaccessible.

In addition, ammonium hydroxides of formula (I) are much stronger bases than ammonia and any organic amines. In fact, their basicity is the same as or greater than that of choline hydroxide. This characteristic provides high anti-corrosion and anti-fouling effectiveness at lower molar contents than those used in prior art methods. Due to the extremely high basicity of ammonium hydroxides of formula (I), they also readily react with protic acids such as hydrogen chloride, hydrogen sulfide and organic acids to form the corresponding salts. In the context of the present invention, the most characteristic acid is usually hydrogen chloride, the reaction of which with ammonium hydroxides of formula (I) leads to the formation of quaternary ammonium chlorides of formula (II) respectively:

in which the variables R ¹ , R ² , R ³ and R ⁴ have the same meanings, in particular the same preferred meanings, as defined in relation to formula (I).

Ammonium hydroxides of formula (I) also readily react with acid ammonium salts, such as, in particular, ammonium chloride, and with organic ammonium salts, releasing ammonia or corresponding amines and forming quaternary ammonium salts, such as, in particular, chlorides formula (II). Thus, the inventors of the present invention have discovered that ammonium chloride dissolves much better when using dilute solutions of ammonium hydroxides of formula (I) than when using choline hydroxide solutions. In conclusion, ammonium hydroxides of formula (I) are well suited for inhibiting corrosion caused by protic acids, as well as for dissolving acid ammonium salts in contaminated systems, and for preventing the formation of such contaminating salt deposits.

The applicability of ammonium hydroxides of formula (I) for the control of corrosion and fouling in chemical plants also depends on the physicochemical characteristics of the salts they form upon reaction with acidic compounds, in particular those selected from protic acids and ammonium acid salts. In this case, the melting and decomposition temperatures of these salts formed from ammonium hydroxides of formula (I) are of particular interest, since they have a significant influence on the behavior of these salts, which are located in certain areas of the plant, which is treated with ammonium hydroxide (I) in accordance with the method proposed in the present invention. More precisely, the melting point determines the temperature at which the fluidity of the salts is significantly improved, while the decomposition temperature determines the temperature at which potentially undesirable decomposition products are formed. According to the invention, it has been found that, in particular, chlorides formed from ammonium hydroxides of formula (I), i.e. salts of formula (II), in many cases have melting points below 80°C and decomposition temperatures above 200 or even above 250°C. Thus, their melting temperatures are often much lower than the melting temperature of choline hydroxide and their decomposition temperatures exceed those typically used in most chemical plant modules. The use of ammonium hydroxides of formula (I) is therefore advantageous since, firstly, the salts formed by their reaction with acidic compounds are already fluid at low temperatures and can thus be easily transferred and removed from the plant module being treated ammonium hydroxide of formula (I). In addition, due to the extremely high decomposition temperature of the resulting salts, they can withstand high operating temperatures without being decomposed and are easily removed from process modules in the form of aqueous solutions. In fact, due to the extremely good solubility of salts in water, the content of even extremely small quantities of liquid water or steam in the process stream being treated is sufficient to ensure the removal of salts.

From the above description it is obvious that not only the ammonium hydroxides of formula (I) used for the treatment corresponding to the method proposed in the present invention, but also the salts into which they are converted by reaction with acidic compounds contained during the chemical process, have extremely high decomposition temperatures. Therefore, the process stream within the apparatus in which the treatment is carried out can be heated to high temperatures without danger of decomposition of the ammonium hydroxides of formula (I) or the salts formed therefrom. Accordingly, the liquid or gaseous stream used in the chemical process may be heated to a temperature of not less than 100°C, often not less than 150°C, preferably not less than 180°C, especially preferably not less than 200°C or not less than 250 °C, during or after the addition of ammonium (I) hydroxide to the stream.

In addition, salts formed from ammonium (I) hydroxides, especially the chlorides of formula (II), are usually not only excellently soluble in water, but also usually are hygroscopic, although the degree of hygroscopicity of different salts (II) varies. Due to the hygroscopicity of salts formed from ammonium (I) hydroxides, such as salts (II), they readily absorb minimal amounts of moisture contained in the process streams being processed, thereby forming flowable solutions. This facilitates easy removal of salts from streams in the form of aqueous solutions that are discharged from various process modules, such as, for example, steam-liquid separators and water-oil separators. Accordingly, by using ammonium (I) hydroxide in accordance with the method of the present invention, deposits containing salts that cause corrosion or contamination, such as ammonium chloride and organic ammonium chlorides, can be effectively removed from the systems being treated.

In addition, as shown in experiments conducted by the present inventors, the addition of even small amounts of extremely hygroscopic chlorides of formula (II) can significantly increase the hygroscopicity of weakly hygroscopic chlorides (II). This is also true in the case of salts other than chlorides formed from ammonium hydroxides of formula (I). Therefore, the mixing of two or more different ammonium hydroxides of formula (I) in specific, easily determined ratios of quantities after treatment allows the formation of a mixture of salts, the hygroscopicity of which is adjusted and precisely adapted to the special requirements of "wet" or "dry" systems, i.e. e. systems with relatively high or low water contents. An example of a wet system is the upper section of a distillation column in which stripping is carried out, such as an atmospheric distillation column. An example of a dry system is the feed/effluent heat exchanger used in the gasoline hydrodesulfurization module. Accordingly, one group of embodiments of the present invention relates to the method proposed in the present invention, which uses a mixture of ammonium (I) hydroxides, which preferably has a certain ratio of their quantities. In this context, mixtures are preferred whose use results in the formation of mixtures of salts (II) that have certain desired physicochemical characteristics, for example optimized hygroscopicity.

Salts of formula (II), as well as salts formed from ammonium hydroxides (I), different from chlorides (II), i.e. compounds of formula (IIa):

in which X" denotes a non-basic and non-acidic counterion, such as a bromide, sulfate or nitrate ion, when dissolved in water, have pH values close to those of a neutral environment, this makes them less corrosive than ammonium chloride and chlorides , formed from amines, usually used to neutralize corrosive acidic compounds, such as, for example, monoethanolamine (MEA).Thus, due to the extremely low corrosivity of salts formed from ammonium (I) hydroxides, especially those of the formula ( II) and (IIa), which are formed when the module used for carrying out the chemical process is treated with ammonium hydroxides of formula (I) in accordance with the method proposed in the present invention, they have practically no adverse effect on the metal surfaces of the module. Therefore, these salts do not cause significant corrosive damage even if they remain in the system for a long time, although they are usually already removed by trace amounts of water or steam contained in the process stream, as described above. In conclusion, the use of ammonium hydroxides of formula (I) as a corrosion and fouling inhibitor provides the added benefit of significantly reducing secondary corrosion, which is often caused by salts formed by the reaction of conventional agents with acidic compounds.

As noted above, the salts formed by the reaction of ammonium hydroxides of formula (I) with acidic compounds, in particular the salts of formula (II), not only have extremely high decomposition temperatures, but they can also be easily removed from chemical process streams. However, in those rare cases when such a salt is exposed to temperatures equal to or greater than its decomposition temperature, it decomposes to form non-hazardous compounds. Thus, the present inventors were able to demonstrate that the pyrolysis of various salts of formula (II) in all cases leads to the formation of the corresponding alkyl chlorides and trialkylamines as the main decomposition products. For example, tetraethylammonium chloride (TEA-Cl) decomposes to form predominantly ethyl chloride and triethylamine, and diethyldimethylammonium chloride (DEDMA-Cl) decomposes to form methyl chloride, ethyl chloride, diethylmethylamine and ethyldimethylamine. The resulting alkyl chlorides are removed from the process system by gas streams eg from separators, columns or heat exchangers, and therefore do not adversely affect the operation of the process or the apparatus in which the process is carried out. On the other hand, the resulting trialkylamines can act as additional bases to neutralize corrosive acidic compounds and can then be removed from the system as ammonium salts. It is important to note that during the thermal decomposition of the salts of formula (II) virtually no corrosive hydrogen chloride is formed. According to this mechanism of thermal decomposition of salts (II), any chlorides formed due to reaction with corrosive or fouling substances such as hydrogen chloride or ammonium chloride are safely and continuously removed from the process plant as alkyl chlorides.

In one set of embodiments of the present invention, at least one quaternary ammonium hydroxide of formula (I) is added during a chemical process in the form of a solution containing one or more ammonium hydroxides (I). Such solutions are preferably prepared by dissolving at least one ammonium (I) hydroxide in a solvent selected from the following: water, C ₁ -C ₄ alkanols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec. -butanol or isobutanol and mixtures thereof. In the context of the present invention, preferred solvents are water, ethanol, n-propanol, isopropanol, n-butanol, isobutanol and sec-butanol, and mixtures thereof, such as mixtures of water with ethanol, propanol, isopropanol, n-butanol, isobutanol or sec. butanol The total concentration of at least one ammonium (I) hydroxide in these solutions is often in the range from 10 to 60 wt. %, preferably in the range from 10 to 50 wt. % and especially preferably in the range from 10 to 40 wt. %.

Solutions of at least one ammonium hydroxide of formula (I) for use in the method of reducing or preventing corrosion or fouling according to the present invention optionally further contain one or more additives, which are, for example, selected from the following: dispersants, such as, for example, polyisobutylene succinimides, antioxidants/anti-polymerization agents, such as, for example, tert-butylphenol derivatives, phenylenediamines, N-oxyl compounds such as 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) and TEMPO derivatives such as 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (4-OH-TEMPO), and antifoam agents such as, for example, ethylene oxide-propylene oxide copolymers, polypropylene glycol or silicone oils. The solutions may also optionally contain additional active agents, including, for example, additional anti-corrosion and antifouling agents such as choline hydroxide and neutralizing amines such as alkylamines or alkanolamines.

In addition, solutions of at least one ammonium hydroxide of formula (I) may also optionally contain active substances which are not intended to combat corrosion or pollution, but have a completely different function. An example of such an active substance is 4-tert-butyl catechol (TBC), which is a polymerization inhibitor and is thus suitable for use as a monomer stabilizer. The solutions of the present invention that contain TBA and at least one ammonium hydroxide of formula (I) are useful for preventing contamination of process units or modules thereof that include monomers, such as process water systems of ethylene production units. The use of a combination of quaternary ammonium hydroxide of formula (I) and TBA provides the unexpected advantage that, due to the strong basicity of ammonium hydroxides of formula (I), they promote the dissolution of weakly acidic TBA in water. Therefore, when preparing bifunctional compositions containing ammonium hydroxide of formula (I) and TBA, there is no need to use other potentially harmful auxiliary substances intended to dissolve TBA.

At least one ammonium hydroxide of formula (I) can be added during the chemical process at one or more positions in the apparatus in which the chemical process is carried out, for example, in different modules of the process plant. Preferably, when carrying out the process, ammonium (I) hydroxides are added by introducing their solutions in one or more positions or into one or more modules of the apparatus or process unit. Administration is usually carried out using a continuous mode of administration, such as administration of a specific amount or administration at an appropriate flow rate, or, alternatively, an intermittent mode of administration, such as suction or forced administration.

At least one ammonium hydroxide of formula (I) is typically introduced into the liquid stream used in the chemical process in an amount ranging from 1 to 5000 ppm, preferably in the range from 1 to 2500 ppm, more preferably in the range of 1 to 1000 ppm, particularly preferably in the range of 1 to 500 ppm, in each case based on the amount of liquid or stream used in the chemical process at each position at which addition is made. It is particularly preferable to control the added amount of ammonium hydroxide of formula (I) to ensure an appropriate amount of corrosive and/or fouling substances, for example in particular the amount of protic acids and/or ammonium acid salts contained in the liquid treatment stream. Thus, ammonium hydroxide of formula (I) is added only in the amount necessary, for example, to neutralize a corrosive acid, such as hydrogen chloride, contained in the stream, or to dissolve deposits containing ammonium chloride formed in the process module. In some cases it is useful, for example, to determine the pH value or chloride concentration in the corresponding part of the process module and, based on the obtained values, determine the amount of ammonium hydroxide of formula (I) that needs to be added. Alternatively, in other cases, when carrying out a known process, it may be sufficient to add a certain amount of ammonium hydroxide of formula (I) which has been experimentally determined to be suitable. In both of the above examples, the addition of ammonium hydroxide of formula (I) is preferably carried out by introducing a solution of ammonium hydroxide of formula (I) at one or more positions in the plant in a continuous or batch mode.

In accordance with preferred groups of embodiments of the method proposed in the present invention, the chemical process is a crude oil processing process, such as a petroleum refining process and/or a petrochemical process, such as, in particular, a petroleum refining process or a petrochemical process. In this context, a petroleum refining process typically involves the use of one or more process modules selected from the following: atmospheric crude oil distillation module, vacuum crude distillation module, visbreaking module, delayed coking module, fluid catalytic cracking module, reforming module, hydrocracking module , alkanolamine processing module, sulfinol processing module and hydrodesulfurization module.

The Crude Distillation Module (CDM), also called the Atmospheric Crude Distillation Module, is typically the first process module in almost all petroleum refining units. The MDP distills the incoming crude oil to produce various fractions with boiling points in different ranges, each of which can then be further processed in other oil refining process modules. Distillation in MDN is usually carried out at a pressure slightly above atmospheric pressure. The MDP typically consists of heat exchangers arranged in series, a desalting device, a furnace and a distillation column, as well as a side stripping section and a reflux collector as its main components. The first preferred addition position, i.e. The position at which one or more ammonium (I) hydroxides, or preferably a solution thereof, can advantageously be added to the MDN is the pipeline exiting the desalting device. The introduction of ammonium hydroxide of formula (I) at this position replaces part or all of the sodium hydroxide that is often used to remove calcium chloride and magnesium chloride from the crude oil leaving the desalter by converting them to the corresponding hydroxides. If calcium and magnesium chlorides remain in the crude oil, they may undergo hydrolysis in the furnace to form hydrogen chloride gas, which will dissolve in the condensed water, for example in the overhead section of a distillation column, and thus cause corrosion. However, the use of sodium hydroxide has disadvantages, one of which is that the sodium salts can poison the catalysts used in downstream process modules, such as hydrodesulfurization or catalytic cracking modules. These disadvantages can be overcome or mitigated by replacing all or part of the sodium hydroxide with ammonium hydroxide of formula (I), in particular since ammonium hydroxide of formula (I) is also a strong base but does not contain sodium.

Other preferred positions in which one or more ammonium(I) hydroxides, preferably a solution thereof, can be advantageously introduced into the MDN are the overhead section and distillation column, as well as associated interconnecting piping, condensers, heat exchangers, receiving tanks and other components. . The introduction of ammonium hydroxides of formula (I) in these positions combats corrosion and salt contamination.

In a vacuum crude distillation (CVCD) unit, the high-boiling final fractions obtained after distillation at atmospheric pressure are usually separated by vacuum distillation. The main component of the MVDN is the distillation column. Preferred positions at which one or more ammonium hydroxides of formula (I), preferably a solution thereof, can be advantageously introduced into the MVDN are the overhead section and distillation column, as well as associated connecting piping, condensers, heat exchangers, receiving tanks and other components. . The introduction of ammonium hydroxides of formula (I) in these positions combats corrosion and salt contamination.

In a visbreaker, also called a viscracker, the vacuum distillation residue is thermally cracked to produce lighter, more valuable components. The main components of a vis cracker are feed/effluent heat exchangers, a furnace, a reaction vessel (reaction chamber), and a distillation column or series of distillation columns. Preferred positions in which one or more ammonium hydroxides of formula (I), preferably a solution thereof, can be advantageously introduced into the vis cracker are the overhead section and the distillation column, as well as the connecting piping, condensers, heat exchangers, receiving tanks connected thereto. and other components. The introduction of ammonium hydroxides of formula (I) in these positions combats corrosion and salt contamination.

The fluid catalytic cracking (FCC) module uses a solid acid catalyst such as zeolites, particularly to separate high boiling residues from crude oil distillation into various low boiling fractions. The MFCC typically includes a first compartment, which includes a reactor and regenerator, and a second compartment, which is generally similar to the MDN. Preferred positions at which one or more ammonium hydroxides of formula (I), preferably a solution thereof, can be advantageously introduced into the MFCC are generally found in the second compartment of the MFCC and are such as the upper section and the distillation column and those attached thereto connecting pipelines, condensers, heat exchangers, receiving tanks and other components. The introduction of ammonium hydroxides of formula (I) in these positions combats corrosion and salt contamination.

In the delayed coking module, residues obtained from vacuum distillation are converted into petroleum coke and lighter fractions by thermal pyrolysis. The delayed coker module mainly includes feed/effluent heat exchangers, a furnace, a distillation column and several coke drums. Preferred positions in which one or more ammonium hydroxides of formula (I), preferably a solution thereof, can be advantageously introduced into the delayed coker unit are the overhead section and the distillation column, as well as the connecting piping, condensers, heat exchangers, receiving tanks and other components. The introduction of ammonium hydroxides of formula (I) in these positions combats corrosion and salt contamination.

The reforming module uses a catalytic reaction to conduct the conversion of typically a naphtha fraction obtained from the distillation of crude oil, which contains relatively low boiling hydrocarbons having low octane numbers, into a high octane reformate product containing branched alkanes and aromatic hydrocarbons. The reformer module typically includes a feed/effluent heat exchanger, a furnace, a series of reactors, a gas separator, a stabilization device, and a reflux collector as its main components. Preferred positions at which one or more ammonium hydroxides of formula (I), preferably a solution thereof, can be advantageously introduced into the reformer module are in the feed/effluent heat exchanger, the recycle gas lines leaving the gas separator, the intermediate reformer product lines , located between the gas separator and the stabilization device, as well as connecting pipelines, condensers, heat exchangers, receiving tanks and other components attached to them.

The hydrocracking module uses a catalytic cracking reaction conducted in the presence of hydrogen gas to produce primarily saturated hydrocarbons from higher molecular weight fractions obtained from petroleum distillation. The hydrocracking module generally includes two reactors, furnaces, feed/effluent heat exchangers and a distillation unit, which is basically similar to MDN, as its main components. Preferred positions in which one or more ammonium hydroxides of formula (I), or preferably a solution thereof, can be advantageously introduced into the hydrocracking module are the feed/effluent heat exchangers and the overhead section of the distillation column, as well as the connecting piping connected thereto, condensers, heat exchangers, receiving tanks and other components.

In the hydrodesulfurization module (HDM), petroleum products are desulfurized using catalytic hydrogenation. An MGDS typically includes feed/effluent heat exchangers, a furnace, a fixed bed reactor, a gas separator, a stripper, and a reflux collector as its main components. Preferred positions at which one or more ammonium hydroxides of formula (I), or preferably a solution thereof, can be advantageously introduced into the MGDS are the feed/effluent heat exchanger and the upper section of the stripper, as well as the connecting piping connected thereto, condensers, heat exchangers, receiving tanks and other components.

Alkanolamine and sulfinol processing modules are gas scrubbing units in which acidic components such as CO ₂ and H ₂ S are removed from useful gas streams such as natural gas and refinery fuel gas. Alkanolamine and sulfinol processing modules are commonly referred to as acid gas scrubbing modules. Such modules mainly include an absorption column, a lean/rich solution heat exchanger, a regeneration column, a reflux collector and connecting piping. A solvent, usually containing an amine solution, circulates in the unit. Acid gases are absorbed by the solvent inside the absorption column at low temperature and high pressure and then sent to the regeneration column operating at high temperature and low pressure. When the solvent moves between the columns, heat exchange occurs between the loaded (enriched) and unloaded (depleted) solutions. Purified gas is produced at the top of the absorption column, while acid gases are removed from the top of the regeneration column. Preferred positions in which one or more ammonium hydroxides of formula (I), or preferably a solution thereof, can be advantageously introduced into the acid gas scrubbing modules are rich/lean solution heat exchangers, the upper section of the regeneration apparatus, the absorption column and the regeneration column , as well as connecting pipelines, condensers, heat exchangers, receiving tanks and other components attached to them.

According to another preferred embodiment of the method of the present invention, the chemical process carried out in the apparatus to which at least one ammonium hydroxide of formula (I) is added is a steam generating process. The apparatus for carrying out such a process is any module capable of generating steam, such as a conventional boiler, a heat recovery steam generator, for example, a heat recovery steam generator included in a petrochemical plant, also called a recovery boiler, a dilution steam generator included in the plant for ethylene production, steam turbine boiler, pressurized water reactor boiler, etc. There are many types of boilers and steam generators, such as cylindrical boilers, water-tube boilers, single-pass boilers, once-through boilers and special boilers such as e.g. indirect heating, waste heat boilers or special fuel boilers. Typically, all internal surfaces of boilers that come into contact with steam or water are susceptible to corrosion, especially if the water system in the boiler contains acidic components. Therefore, it is extremely important to take measures to reduce or prevent corrosion in boilers.

Corrosion in boilers and steam generators can be advantageously prevented by adding at least one quaternary ammonium hydroxide of formula (I) or, preferably, a solution thereof, to the aqueous system used therein. Ammonium hydroxides of formula (I) neutralize acids and other acidic compounds contained in water or in an aqueous solution located inside the boiler, and thus they are capable of maintaining a pH value that is high enough to prevent corrosion completely or at least in to a large extent. Typically, ammonium(I) hydroxides can be added or introduced into any location within the boiler, such as, in particular, one of the typically three boiler water systems, i.e. the supply water system, the water system inside the boiler and the steam/condensed water system. However, since the neutralization region is more broadened, if at least one ammonium (I) hydroxide is added upstream, it is generally preferable if it is added to the feed water system.

Other objects of the present invention are the use of the quaternary ammonium hydroxides of formula (I) described in the present invention, especially those defined in the present invention as being preferred, for reducing or preventing corrosion or fouling in an apparatus intended to carry out a chemical process where corrosion or fouling caused by acidic compounds contained during the chemical process. Such applications of quaternary ammonium hydroxides of formula (I) in any of the methods of the present invention described in the present invention are preferred.

The following examples are intended to further illustrate the present invention.

BLUEPRINTS

Figure 1: GC (gas chromatography)/MS (mass spectrometry) partial chromatogram of the DEDMA-Cl pyrolysis products formed under the conditions described in example 10.

EXAMPLES

Analysis methods:

Ion chromatography: Column: Metrosep C4-250/4.0 - weak cation exchange material based on silicon dioxide, diameter: 5 microns. Substrate: polybutadiene with surface copolymerized maleic acid to provide functional carboxy groups. Capacity: no less than 29 µeq/column Pre-column: Metrosep C4 Guard

Autosampler: 863 Compact Autosampler

Temperature: 20-25°C

Detection: electrical conductivity at 40°C

Flow rate: 0.9ml/min

Eluent: 0.7 mmol/l dipicolinic acid, 1.7 mmol/l HNO ₃ , 0.05 mmol/l

18-crown-6, 1% acetone; rest: ultrapure water

Injected volume: 20 µl

Duration: 40 min

Typical conductivity: 635±5 µS

System pressure: 12.5±0.5 MPa

TGA:

TGA was performed using a TGA instrument: TGA Q 5000, TA Instruments. The research parameters were as follows:

Heating speed: 10 K/min

Sample weight: 6-7 mg

Purge gas: N ₂ , 3 l/h

Sample cup: Al crucible, open

One heating cycle: from room temperature to 600°C

DSK

DSC was performed using a DSC instrument: pDSC Q20, TA Instruments. The research parameters were as follows:

Heating speed: 10 K/min

Cooling speed: manual control

Sample weight: 6-8 mg

Purge gas: N ₂ , 3 l/h

Sample cup: Al crucible, open

First heating cycle: from approximately -30°C to 200-400°C (depending on the sample)

First cooling cycle: from 200-400°C to approximately -30°C

Second heating cycle: from approximately -30°C to 200-400°C (depending on the sample)

Example 1: Stability of aqueous solutions of ammonium (I) hydroxides during storage

The commercially available ammonium(I) hydroxide solutions listed in Table 1 were placed in small glass vials, stored for 2 months at 5°C, 20°C and 40°C, respectively, and visually inspected periodically. A concentrated solution of choline hydroxide was used as a standard. The results are shown in Table 1.

As can be seen from the results given in Table 1, when stored at 40°C, the choline hydroxide solution turned yellow over time. It also took on a special fishy smell. In contrast, aqueous solutions of the studied ammonium (I) hydroxides remained transparent and colorless and did not acquire a strong odor. When studying mixed solutions of these ammonium (I) hydroxides, similar results were obtained.

Example 2: Thermal stability of aqueous solutions of ammonium (I) hydroxides

Solutions of several ammonium (I) hydroxides were prepared in deionized water at a concentration of 100 ppm and placed in stainless steel autoclaves, which were then purged with nitrogen and heated at 220° C. for 4 h and then cooled to room temperature. Solutions were analyzed before and after heat treatment using ion chromatography according to the method described above. Choline hydroxide was used as a standard. The average values for the two experiments are shown in Table 2. The percent stability values given in Table 2 correspond to the measured values for the remaining amounts of ammonium hydroxides of formula (I).

Thermal stability experiments were repeated by heating at a temperature of 240°C for 1 hour. The average values for the two experiments are given in Table 3. The percentage stability values given in Table 3 correspond to the measured values of the remaining amounts of ammonium hydroxides ( I).

From the results presented in Tables 2 and 3, it is obvious that the thermal stability of dilute aqueous solutions of ammonium (I) hydroxides is significantly higher than the thermal stability of the corresponding choline hydroxide solution.

Example 3: pH values of aqueous solutions of quaternary ammonium hydroxides of formula (I)

Ammonium(I) hydroxides were dissolved in deionized water at a concentration of 8.25 mmol/L, and the pH values of these solutions were determined using a calibrated pH electrode. For comparison, the pH values of the corresponding solutions of ammonia, MEA and choline hydroxide were also determined. The results are shown in Table 4.

The results shown in Table 4 show that the solutions of the studied ammonium hydroxides of formula (I) are much more alkaline (about 10-100 times) than the solutions of ammonia and MEA, and their basicity is the same as or higher than the basicity of choline hydroxide .

Example 4: Solubility of ammonium chloride in dilute aqueous solutions of quaternary ammonium hydroxides of formula (I)

Ammonium chloride (0.1 g) was placed on a watch glass and in each case 1 wt. was added dropwise using a plastic pipette. % aqueous solution of ammonium hydroxide (I) until ammonium chloride is completely dissolved. 1 wt. was used as a standard. % choline hydroxide solution. Table 5 shows the results in the form of the number of drops required to completely dissolve the salt.

All tested solutions provided dissolution of ammonium chloride, which was accompanied by the release of ammonia gas. However, the volumes of ammonium (I) hydroxide solutions required to ensure complete dissolution were significantly smaller than the volume of choline hydroxide solution required to ensure complete dissolution.

Example 5: Melting points and decomposition temperatures of chlorides formed from quaternary ammonium hydroxides of formula (I)

Melting points and decomposition temperatures of chlorides formed from ammonium(I) hydroxides, as well as some comparative chlorides, were determined by DSC and TGA as described above. The results obtained are shown in Table 6. As indicated, some values are taken from literature sources.

[1] N. Collie et al.; The action of heat on the chlorides and hydroxides of mixed quaternary ammonium compounds; Journal of the Chemical Society, Transactions, Volume 57 (1890), 767-782

[2] J. Blazejowski et al.; Thermal decomposition of alkylammonium chlorides; Thermochimica Acta, 92 (1985), 811-814

[3] "International Chemical Safety Data Sheets" were obtained from the National Institute for Occupational Safety and Health (USA) (using Scifinder, Chemical Abstract Service, CAS, USA)

[4] Wystrach, V. P.; Journal of the American Chemical Society 1955, V77, P5915-18

[5] Data on “physical characteristics” were obtained from Syracuse Research Corporation of Syracuse, New York (US); (using Scifinder, Chemical Abstract Service, CAS, USA)

From the results given in Table 6, it is evident that the melting points of the chlorides formed from quaternary ammonium hydroxides of formula (I), in particular those formed from GTEA, GTPA, GTBA, HDEDMA and GTEMA, are comparatively low compared to the melting points of ammonium chloride and chloride choline It can also be seen that the chlorides formed from ammonium hydroxides of formula (I) decompose only at high temperatures.

Example 6: Hygroscopicity of chlorides formed from quaternary ammonium hydroxides of formula (I)

Chlorides formed from ammonium (I) hydroxides were obtained by careful neutralization of 5 wt. % hydrochloric acid solutions using equimolar amounts of ammonium hydroxides of formula (I) until the pH value corresponds to a slightly acidic environment (pH 5.5-6.5), removing water using a rotary evaporator (absolute pressure: 15 mbar, 80 ° C) , transferring the resulting crude salt into isopropanol and evaporating the solvent in a clean flask using a rotary evaporator. To perform high-precision analytical studies, such as pH and corrosion studies, several purification steps were carried out for some of the salts using isopropanol washing steps, which were carried out several times in succession.

The thus obtained dried chlorides, formed from the corresponding ammonium (I) hydroxides, were placed on watch glasses, stored open in the laboratory in ambient air with a relative humidity of 50%, and observations were carried out for 24 hours. The degree of dissolution was assessed salts Ammonium chloride, MEA-Cl (monoethanolammonium chloride) and choline chloride were used as standards.

The hygroscopicity of salts was assessed according to the following scale:

1: extremely hygroscopic: dissolution in less than 10 minutes;

2: highly hygroscopic: dissolution in less than 1 hour;

3: moderately hygroscopic: dissolution within 1 to 6 hours;

4: slightly hygroscopic; dissolution within 6 to 24 hours;

5: non-hygroscopic: no visible changes within 24 hours.

The results are shown in Table 7.

From the results shown in Table 7, it can be seen that the hygroscopicity of chlorides formed from ammonium (I) hydroxides ranges from weak to extremely strong. Accordingly, these chlorides absorb moisture in the environment and thus, in the presence of moisture, they turn into fluid solutions. Additional studies were carried out using mixtures of salts containing TEA-Cl, i.e. slightly hygroscopic salt, and choline chloride, DEDMA-Cl, TEMA-Cl or TPA-S ₁ , i.e. extremely hygroscopic salt, with a mass ratio of 9:1. These mixtures were highly hygroscopic compared to the hygroscopicity of, for example, TEA-Cl alone.

Additional studies were conducted using chloride(II) in gasoline with a few ppm of water added to demonstrate the ability of the salts to absorb moisture even from non-polar hydrocarbon liquids.

Example 7: pH values of chlorides formed from quaternary ammonium hydroxides of formula (I)

Purified chlorides formed from ammonium (I) hydroxides were dissolved in deionized water at a concentration of 10 wt. %, and the pH values of these solutions were determined using a calibrated pH electrode. Ammonium chloride, MEA-Cl and choline chloride were used as standards. The results are shown in Table 8.

The results shown in Table 8 show that aqueous solutions of chlorides formed from ammonium (I) hydroxides do not have pH values corresponding to an acidic environment, but rather have pH values corresponding to an approximately neutral environment.

Example 8: Corrosivity of chlorides formed from quaternary ammonium hydroxides of formula (I)

30 wt. was placed in test tubes for research (volume: 15 ml). % aqueous solutions of purified chlorides formed from ammonium (I) hydroxides. A pre-weighed carbon steel plate was placed in each test tube, the tubes were then loosely sealed to allow hydrogen gas produced by corrosion to escape, and immersed vertically in an oil bath at 70°C for 24 hours. The plates were removed from the solutions, and all corrosion products were removed from their surfaces by carefully treating them with 10 wt. % hydrochloric acid solution, they were washed with deionized water, dried using acetone and weighed. The degree of corrosion was then determined based on the weight loss of the plates. The average values for the two experiments are given in Table 9.

From the results given in Table 9, it can be seen that the corrosivity of chlorides formed from quaternary ammonium (I) hydroxides is much lower than the corrosivity of ammonium chloride and MEA-Cl, and thus it corresponds to the low corrosivity of choline chloride .

Example 9: Thermal stability of chloride solutions formed from quaternary ammonium hydroxides of formula (I)

The experiments described in Example 2 were repeated using aqueous solutions of chlorides formed from quaternary ammonium (I) hydroxides at a concentration of 100 ppmw at a temperature of 220° C. for 4 hours. As a reference Choline chloride was used. The average values for the two experiments are given in Table 10.

From the results presented in Table 10, it can be seen that the stability of chlorides is usually higher than the stability of their parent hydroxides (comparison with the results given in Table 2). In addition, it can be seen that the stability of dissolved chlorides formed from ammonium(I) hydroxides is higher than the stability of choline chloride solution. The lower stability of choline chloride in aqueous solution is quite unexpected, taking into account the high thermal stability of solid choline chloride (see Table 6).

Example 10: Thermal decomposition of chlorides formed from quaternary ammonium hydroxides of formula (I)

Pyrolysis was carried out using small amounts of pure chlorides formed from quaternary ammonium (I) hydroxides and the compositions thus obtained were analyzed using gas chromatography coupled to mass spectrometry (pyrolytic GC/MS).

The conditions were as follows:

pyrolysis temperature: 760°C,

duration of pyrolysis: 20 s;

column: capillary column CP-select 624 SV (Agilent Technologies), length: 30 m, film thickness: 1.8 µm, internal diameter: 320 µm;

detector: mass detector,

Compound identification: comparison with NIST17 database spectra.

The main decomposition products of the compounds are given in Table 11.

Table 11 shows that chlorides formed from quaternary ammonium (I) hydroxides decompose to form the corresponding organic chlorides and tertiary amines, and in particular that in all cases virtually no hydrogen chloride is formed. This result is in accordance with what is described in the publications of N. Collie et al., J. Chem. Soc, Trans.1890, 57, 767-782; J. Blazejowski et al., Thermochim. Acta 1985, 92, 811-814; K.M. Harmon et al., Inorg. Chem. 1981, 20(11), 4013-4015; K. M. Harmon et al., Journal of Molecular Structure 1989, 213, 193-200, and J. Blazejowski et al., Thermochim. Acta 1986, 105, 257-285.

As a typical example, Figure 1 shows a partial chromatogram obtained from studying the pyrolysis of DEDMA-Cl using pyrolytic GC/MS. If HCl is present, it is detected at an extremely low retention time. When studying the pyrolysis of DEDMA-Cl, the presence of HCl was not detected.

Example 11: Ability of chlorides formed from ammonium (I) hydroxides to retain hydrogen chloride

The ability of chlorides formed from quaternary ammonium (I) hydroxides to retain hydrogen chloride was studied using a procedure similar to that described in US 8177962 (see Study Example 1). More specifically, an automatic distillation module such as that used for automatic distillation of crude oil samples was used (see ASTM D 86, IP 123 and ISO 3405 standards). Each sample contained 95 wt. % heavy aromatic solvent having a boiling point of 180 to 210°C, and 5 wt. % of the aqueous phase containing 9 mmol of chloride formed from GTEA, i.e. from ammonium hydroxide (I). Chlorides such as ammonium chloride, monoethanolammonium chloride and choline chloride were used as standards. The samples were distilled to dryness using an automatic distillation apparatus in which the distillation rate was maintained at a constant rate. The aqueous phases of the resulting distillates were separated from the organic phases on top, and the concentrations of chloride ions in them were determined by titration with silver nitrate. The average values for three experiments are given in Table 12.

From the results shown in Table 12, it can be seen that choline chloride and TEA-Cl release much less chloride ions than ammonium chloride and monoethanolammonium chloride. Therefore, the ability of TEA-Cl to retain HCl is at least as high as that of choline chloride.

Claims (41)

1. A method for controlling corrosion in an apparatus for carrying out a chemical process, where corrosion is caused by acidic compounds contained in a chemical process, being a petroleum refining process, a petrochemical process or a steam generating process, which involves adding to the apparatus in which the chemical process is carried out at least at least one quaternary ammonium hydroxide of formula (I): [Chemical formula 1] wherein R ¹ , R ² , R ³ are all independently C ₁ -C ₆ -alkyl; R ⁴ is C ₂ -C ₁₈ -alkyl; R ³ and R ⁴ together with a nitrogen atom can also form a 5 or 6 membered saturated nitrogen atom containing heterocycle which is unsubstituted or contains 1 or 2 methyl groups; wherein the chemical process is a petroleum refining process or a petrochemical process and involves adding a compound of formula (I) to at least one module selected from the following: an atmospheric crude oil distillation module, a vacuum crude distillation module, a visbreaking module, a delayed coker module, fluid catalytic cracking module, reforming module, hydrocracking module, alkanolamine processing module, sulfinol processing module and hydrodesulfurization module, or wherein the chemical process is a steam generating process and involves adding a compound of formula (I) to the water system of a boiler or steam generator; and wherein the compounds contained in the chemical process are selected from the group consisting of the following: hydrogen halides, hydrogen sulfide, hydrogen cyanide, thiocyanic acid, sulfuric acid, SO ₂ , SO ₃ , nitrogen oxides, CO ₂ , carbonic acid, acid containing phosphorus compounds and ammonium acid salts, and mixtures thereof. 2. A method for controlling contamination in an apparatus for carrying out a chemical process, where the contamination is caused by acidic compounds contained in a chemical process, being a petroleum refining process, a petrochemical process or a steam generating process, which involves adding to the apparatus in which the chemical process is carried out, according to at least one quaternary ammonium hydroxide of formula (I): [Chemical formula 1] wherein R ¹ , R ² , R ³ are all independently C ₁ -C ₆ -alkyl; R ⁴ is C ₂ -C ₁₈ -alkyl; R ³ and R ⁴ together with a nitrogen atom can also form a 5 or 6 membered saturated nitrogen atom containing heterocycle which is unsubstituted or contains 1 or 2 methyl groups; wherein the chemical process is a petroleum refining process or a petrochemical process and involves adding a compound of formula (I) to at least one module selected from the following: an atmospheric crude oil distillation module, a vacuum crude distillation module, a visbreaking module, a delayed coker module, fluid catalytic cracking module, reforming module, hydrocracking module, alkanolamine processing module, sulfinol processing module and hydrodesulfurization module, or wherein the chemical process is a steam generating process and involves adding a compound of formula (I) to the water system of a boiler or steam generator; and wherein the compounds contained in the chemical process are selected from the group consisting of the following: hydrogen halides, hydrogen sulfide, hydrogen cyanide, thiocyanic acid, sulfuric acid, SO ₂ , SO ₃ , nitrogen oxides, CO ₂ , carbonic acid, acid containing phosphorus compounds and ammonium acid salts, and mixtures thereof. 3. Method according to claim 1 or 2, where in formula (I) R ¹ , R ² , R ³ are all independently C ₁ -C ₆ -alkyl and R ⁴ denotes C ₂ -C ₆ -alkyl. 4. The method according to claim 1 or 2, where the compound of formula (I) is selected from the group consisting of the following: diethyldimethylammonium hydroxide, ethyltrimethylammonium hydroxide, dimethyldipropylammonium hydroxide, triethylmethylammonium hydroxide, tetraethylammonium hydroxide, tetra-n-propylammonium hydroxide, tetra-n hydroxide -butylammonium, hexamethonium hydroxide and N,N-dimethylpyrrolidinium hydroxide. 5. The method according to claim 1 or 2, wherein the compound of formula (I) is selected from the group consisting of the following: diethyldimethylammonium hydroxide, ethyltrimethylammonium hydroxide, dimethyldipropylammonium hydroxide, triethylmethylammonium hydroxide, tetraethylammonium hydroxide, tetra-n-propylammonium hydroxide and tetra-n hydroxide -butylammonium. 6. The method according to claim 1 or 2, wherein the acidic compounds contained in the chemical process include at least one acidic compound selected from the group consisting of the following: ammonium halides, ammonium hydrosulfide, ammonium sulfide, ammonium hydrogensulfate, ammonium sulfate . 7. The method according to claim 1 or 2, where the chemical process is an oil refining process or a petrochemical process. 8. The method according to claim 1 or 2, where the chemical process is a steam generating process. 9. Method according to claim 1 or 2, wherein the compound of formula (I) is added to the liquid or gaseous stream used to carry out the chemical process. 10. The method according to claim 9, wherein during or after the addition of the compound of formula (I) the temperature of the liquid or gaseous stream is set to at least 150°C and especially preferably at least 180°C. 11. The method according to claim 9 or 10, wherein the compound of formula (I) is added in an amount equal to from 1 to 1000 ppm by weight, based on the amount of liquid or gaseous stream used in the chemical process. 12. The method according to claim 1 or 2, wherein the compound of formula (I) is added during the chemical process in the form of a solution containing at least one compound of formula (I). 13. The method according to claim 12, wherein at least one compound of formula (I) is dissolved in a solvent selected from the following: C ₁ -C ₄ alkanols, water and mixtures thereof. 14. The method according to claim 11 or 12, wherein the total concentration of the compound of formula (I) in solution is in the range from 10 to 60 wt.%. 15. The use of a compound according to claim 1 for controlling corrosion in an apparatus intended for carrying out a chemical process, where the corrosion is caused by acidic compounds contained in the carrying out of the chemical process, where the chemical process is a petroleum refining process or a petrochemical process and includes the addition of a compound of formula (I) at least one module selected from the following: atmospheric crude oil distillation module, vacuum crude distillation module, visbreaking module, delayed coking module, fluid catalytic cracking module, reforming module, hydrocracking module, alkanolamine processing module, sulfinol processing module and a hydrodesulfurization module, or wherein the chemical process is a steam generating process and involves adding a compound of formula (I) to the water system of a boiler or steam generator; and wherein the compounds contained in the chemical process are selected from the group consisting of the following: hydrogen halides, hydrogen sulfide, hydrogen cyanide, thiocyanic acid, sulfuric acid, SO ₂ , SO ₃ , nitrogen oxides, CO ₂ , carbonic acid, acid containing phosphorus compounds and ammonium acid salts, and mixtures thereof. 16. The use of a compound according to claim 1 to combat contamination in an apparatus intended for carrying out a chemical process, where the contamination is caused by acidic compounds contained during the chemical process, wherein the chemical process is a petroleum refining process or a petrochemical process and involves adding a compound of formula (I) to at least one module selected from the following: an atmospheric crude oil distillation module, a vacuum crude distillation module, a visbreaking module, a delayed coker module, fluid catalytic cracking module, reforming module, hydrocracking module, alkanolamine processing module, sulfinol processing module and hydrodesulfurization module, or wherein the chemical process is a steam generating process and involves adding a compound of formula (I) to the water system of a boiler or steam generator; and wherein the compounds contained in the chemical process are selected from the group consisting of the following: hydrogen halides, hydrogen sulfide, hydrogen cyanide, thiocyanic acid, sulfuric acid, SO ₂ , SO ₃ , nitrogen oxides, CO ₂ , carbonic acid, acid containing phosphorus compounds and ammonium acid salts and mixtures thereof.