WO2021152718A1

WO2021152718A1 - Method for preventing fouling of heat exchanger in petroleum processing

Info

Publication number: WO2021152718A1
Application number: PCT/JP2020/003148
Authority: WO
Inventors: 加藤慶
Original assignee: 株式会社片山化学工業研究所; ナルコジャパン合同会社
Priority date: 2020-01-29
Filing date: 2020-01-29
Publication date: 2021-08-05
Also published as: JP7480962B2; JPWO2021152718A1

Abstract

Provided are a novel method and a fouling-preventing agent, each of which makes it possible to prevent corrosion caused by a fouling-preventing agent during the prevention of the fouling of a heat exchanger in a petroleum processing. A method for preventing the fouling of a heat exchanger in a petroleum processing, the method comprising adding a phosphorous acid ester compound and a dispersing agent to a process fluid that passes through the heat exchanger, wherein the dispersing agent is a succinimide compound.

Description

How to prevent heat exchanger stains in petroleum processes

This disclosure relates to a method for preventing heat exchanger stains in the petroleum process.

In the distillation process of an oil refining plant for refining crude oil, the crude oil is heated in a heat exchanger and a heating furnace and then sent to a distillation tower for distillation operation. Crude oil undergoes heat history in heat exchangers and heating furnaces, and a large amount of dirt adheres to it. As one form of the dirt component, there is a form in which an organic polymer component such as asphaltene or sludge is mixed. Adhesion of dirt causes a decrease in the heat exchange rate of heat exchangers and heating furnaces, resulting in an increase in the amount of fuel used to maintain the outlet temperature.

Patent Document 1 discloses a stain-preventing agent and a stain-preventing method for a heat exchanger and a heating furnace to be added to a process fluid before a desalter. Patent Document 2 discloses a method of preventing stains derived from asphaltene in preheating in a petroleum process by using a phosphate ester-based anticorrosive agent and a dispersant. Patent Document 3 discloses a method of preventing stains derived from asphaltene in preheating in a petroleum process by using a phosphite ester-based anticorrosive agent and a dispersant.

Japanese Unexamined Patent Publication No. 2010-1653539 WO2015 / 022979 WO2018 / 207708

In Patent Document 3, when a phosphoric acid ester is used as an antifouling agent, the problem of corrosion of the storage tank and the chemical injection facility due to the phosphoric acid ester is found, and in order to solve the problem, the phosphoric acid ester is replaced with a sub-phosphate ester. It is proposed to use phosphate ester.
On the other hand, according to the method of Patent Document 3, the present inventor may not be able to suppress the corrosion caused by the antifouling agent in the carbon steel (SPCC) storage tank and the chemical injection equipment which are widely used. In particular, when the storage tank and chemical injection equipment are exposed to high temperatures, or when the temperature of the antifouling agent in the storage tank and chemical injection equipment becomes high, the storage tank and chemical injection equipment are corroded by the antifouling agent. We found that it was not possible to withstand the problem, and that the material of the chemical injection equipment had to be changed to a corrosion-resistant material such as stainless steel.

The present disclosure, in one aspect, provides a new method and antifouling agent capable of suppressing corrosion by the antifouling agent in preventing fouling of the heat exchanger in the petroleum process.

The present disclosure, in one aspect, is a method of preventing fouling of a heat exchanger in a petroleum process, which comprises adding a phosphite ester compound and a dispersant to the process fluid passing through the heat exchanger. The present invention relates to a stain prevention method in which the dispersant is a succinimide compound.

The present disclosure is, in other embodiments, an antifouling agent for use in the antifouling method of the present disclosure, which contains a phosphite ester compound and a dispersant, wherein the dispersant is an succinimide compound. , Regarding antifouling agents.

According to the present disclosure, it is possible to provide a method and an antifouling agent that can prevent the heat exchanger from becoming dirty in the petroleum process while suppressing the corrosion of the chemical injection equipment and the like due to the antifouling agent.

FIG. 1 is a block diagram showing an example of an oil refining processing apparatus provided with an atmospheric distillation column. FIG. 2 is a cross-sectional view of the heating tube used in the stain prevention test. FIG. 3 is a cross-sectional view of a state in which the heating tube is inserted into the heating tube cage in the stain prevention test.

In the present disclosure, by using a phosphite ester compound in combination with a dispersant which is a succinimide compound such as succinimide having an alkenyl group, the material of the storage tank and the chemical injection facility is more corrosion resistant than stainless steel. Even when low carbon steel is used and the storage tank and chemical injection equipment are exposed to high temperatures exceeding 100 ° C, heat exchange such as preheating exchange of the petroleum process is performed while suppressing corrosion by the antifouling agent. Based on the knowledge that the vessel can be prevented from becoming dirty.
The present disclosure prevents stains derived from organic polymer components such as asphaltene and sludge regardless of the asphaltene content of crude oil by using the phosphite ester compound in combination with a dispersant which is a succinimide compound. Based on the finding that it can be done.

According to the present disclosure, in one or more embodiments, dirt in a heat exchanger of a petroleum process is used while using conventional commonly used medicinal equipment without changing the material of the medicinal equipment. Prevention can be done.
According to the present disclosure, in one or more embodiments, stains on the heat exchanger such as preheat exchange in the petroleum process can be prevented regardless of the asphaltene content of the crude oil, preferably not only stains derived from asphaltene but also other than asphaltene. For example, dirt such as sludge can be prevented, and preferably the heat exchange rate of the heat exchanger can be improved / maintained, and fuel cost and cleaning cost can be suppressed.

In the present disclosure, the term "petroleum process" refers to all or part of the process from hydrocarbons such as crude oil to the production of various petroleum products. In one or more embodiments, the petroleum process involves heating hydrocarbons such as crude oil, and utilizing the difference in boiling points of these heated hydrocarbons in an atmospheric distillation apparatus to utilize the difference in boiling points to volatile oils such as LPG and naphtha and light oil. It can at least include separation into various components such as. The petroleum process in the present disclosure may include a petroleum refining process in one or more embodiments.

In the stain prevention method of the present disclosure, the "heat exchanger" is a heat exchanger used in a petroleum process. Examples of the heat exchanger include, in one or more embodiments without limitation, preheating exchanges (also referred to as preheating heat exchanges or preheating exchangers), preheaters, reboilers, and the like. In these heat exchangers, it is the high temperature portion of about 200 ° C. or higher that is particularly liable to generate and accumulate dirt. In one or more embodiments of the present disclosure, a high temperature portion having a temperature of about 200 ° C. or higher, for example, 180 ° C. or higher, 190 ° C. or higher, 200 ° C. or higher, 210 ° C. or higher, or 220 ° C. or higher during treatment is provided. This is a method for preventing stains on a heat exchanger. In one or more embodiments, the stain prevention method of the present disclosure more effectively exerts the stain prevention effect at a portion of about 200 ° C. or higher.
Examples of the heat exchanger in the petroleum process include heat exchangers in the petroleum refining process, preheating exchanges in the petroleum process, and the like in one or more embodiments.

In the present disclosure, "process fluid" means a liquid or gas provided in a petroleum process. Examples of the process fluid include crude oil processed in a petroleum process, hydrocarbons derived thereto, and the like in one or more embodiments. The process fluid includes, in one or more embodiments not particularly limited, a liquid supplied to the preheat exchange in the petroleum refining process, a liquid in the preheat exchange, and the like.

In the stain prevention method of the present disclosure, "dirt" refers to one containing organic polymer components such as asphaltene and sludge in one or more embodiments without limitation, or adhering and adhering in a heat exchanger. / Or stains containing organic polymer components such as asphaltene and sludge that accumulate. Therefore, the prevention of contamination in the heat exchanger in the present disclosure is, in one or more embodiments, suppressing the adhesion and / or accumulation of organic polymer components such as asphaltene and sludge in the heat exchanger.

The content of asphaltene in crude oil varies depending on the oil producing area and the oil producing time. The content of asphaltene in the crude oil is, for example, 15% by weight or less, 10% by weight or less, 5% by weight or less, 3% by weight or less, or 1% by weight or less. The content of asphaltene in the process fluid will vary depending on the crude oil used and the refining process in one or more embodiments. In the stain prevention method of the present disclosure, since the phosphite ester compound is used in combination with the dispersant which is a succinimide compound, it is possible to prevent the heat exchanger from being soiled regardless of the asphaltene content of the process fluid. can.

[How to prevent stains]
The present disclosure relates, in one aspect, to a method for preventing stains on a heat exchanger in a petroleum process (a method for preventing stains in the present disclosure). The antifouling method of the present disclosure comprises adding a phosphite ester compound and a dispersant to a process fluid passing through a heat exchanger in a petroleum process, the dispersant being a succinimide compound.

[Phosphite ester compound]
Phosphite ester compounds used in the antifouling method of the present disclosure include phosphite ester compounds used in petroleum processes in one or more embodiments.

The phosphite ester compound is not particularly limited, and in one or more embodiments, the phosphite ester compound represented by the formulas (I) to (IV), a compound containing two structures of the formula (II), or a compound having two structures of the formula (II). Examples thereof include a dimer (dimer) of the compound of the formula (II).

In formula (I), R ¹ and R ² are groups having 1 to 30 carbon atoms. R ¹ and R ² may be the same or different from each other, but are preferably the same.

In formula (II), R ³ , R ⁴ and R ⁵ are groups having 1 to 30 carbon atoms. R ³ , R ⁴ and R ⁵ may be the same or different from each other, but are preferably the same.

In formula (III), R ⁶ , R ⁷ , R ⁸ and R ⁹ are groups having 1 to 30 carbon atoms, and R ¹⁰ and R ¹¹ are divalent substitutions having 1 to 30 carbon atoms. A group, X ¹ is a divalent substituent having an oxygen atom, a carbon atom or 1 to 5 carbon atoms. R ⁶ , R ⁷ , R ⁸ and R ⁹ may be the same or different from each other, but are preferably the same. R ¹⁰ and R ¹¹ may be the same or different from each other.

In formula (IV), R ¹² and R ¹³ are groups with 1 to 30 carbon atoms, and R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ are divalent substitutions with 1 to 30 carbon atoms. It is a group and X ² is a carbon atom. R ¹² and R ¹³ may be the same or different from each other. R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ may be the same or different from each other.

Examples of the group having 1 to 30 carbon atoms include an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 1 to 30 carbon atoms, and an aryl group having 6 to 30 carbon atoms in one or more embodiments. , An alalkyl group having 7 or more and 30 or less carbon atoms, or an alkylaryl group having 7 or more and 30 or less carbon atoms. Alkyl groups, alkenyl groups, aryl groups, alalkyl groups, and alkylaryl groups may have substituents in one or more embodiments. The alkyl group may be a straight chain alkyl group or a branched chain alkyl group in one or more embodiments.
Examples of the divalent substituent having 1 to 30 carbon atoms include an alkylene group having 1 to 30 carbon atoms in one or more embodiments. The alkylene group may have a substituent in one or more embodiments. The alkylene group may be a straight chain alkylene group or a branched chain alkylene group in one or more embodiments.

Examples of the phosphite ester compound represented by the formula (I) include diethylhydrogen phosphite, bis (2-ethylhexyl) hydrogen phosphite, bis (tridecylic) hydrogen phosphite, and dilauryl hydrogen in one or more embodiments. Examples thereof include phosphite, diolyl hydrogen phosphite, and diphenylhydrogen phosphite.

Examples of the phosphite ester compound represented by the formula (II) include triphenylphosphine, trisnonylphenylphosphine, tricresylphosphite, triethylphosphite, and tris (2-ethylhexyl) in one or more embodiments. ) Phosphite, tridecylphosphite, trilaurylphosphite, tris (tridecyl) phosphite, trioleyl phosphite, tristearyl phosphite, diphenylmono (2-ethylhexyl) phosphite, diphenylmonodecylphosphite, diphenylmono ( Examples thereof include tridecyl) phosphite and tris (2,4-di-tert-butylphenyl) phosphite.

The phosphite ester compound represented by the formula (III), in one or more embodiments, tetraphenyl dipropylene glycol diphosphite, and tetra (C ₁₂ - ₁₅ alkyl) -4,4'-isopropylidene Examples thereof include diphenyldiphosphite.

The phosphite ester compound represented by the formula (IV) includes, in one or more embodiments, a mixture of bis (tridecyl) pentaerythritol diphosphite and bis (nonylphenyl) pentaerythritol diphosphite, bis. (Tridecyl) pentaerythritol diphosphite, bis (decyl) pentaerythritol diphosphite, and distearyl pentaerythritol diphosphite, tetraphenyl (tetratridecyl) pentaerythritol tetraphosphite, and hydrogenated bisphenol A / pentaerythritol phos. Examples include fighter polymers.

Phosphite ester compounds include triphenylphosphite, tris, in one or more embodiments, from the perspective of further preventing contamination of the heat exchanger in the petroleum process and / or further suppressing corrosion of storage tanks and chemical injection facilities. Nonylphenyl phosphite, tricresyl phosphite, triethyl phosphite, tris (2-ethylhexyl) phosphite, tridecyl phosphite, trilauryl phosphite, tris (tridecyl) phosphite, trioleyl phosphite, tristearyl phosphite , Diphenylmono (2-ethylhexyl) phosphite, diphenylmonodecylphosphite, diphenylmono (tridecyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, diethylhydrogen phosphite, bis (2- Ethylhexyl) hydrogen phosphite, bis (tridecyl) hydrogen phosphite, dilauryl hydrogen phosphite, diorail hydrogen phosphite, or a combination thereof is preferable. From the same viewpoint, the phosphonic acid type phosphite ester compound is preferable as the phosphite ester compound, and diethylhydrogen phosphite, bis (2-ethylhexyl) hydrogen phosphite, bis (tridecyl) hydrogen phosphite, and dilauryl hydrogen. Phosphite, diorail hydrogen phosphite or a combination thereof is more preferable.

The phosphite ester compound may be used alone or in combination of a plurality of types in one or more embodiments.

The concentration of the phosphite ester compound (the total of the phosphite ester compounds when using a plurality of types) in the process fluid supplied to the heat exchanger is 1 to 100 ppm, 2 in one or more embodiments. Examples thereof include ~ 80 ppm, or 3 to 50 ppm. In one or more embodiments, the antifouling method of the present disclosure is such that the concentration of phosphite ester in the process fluid supplied to the heat exchanger is 1 to 100 ppm, 2 to 80 ppm, or 3 to 50 ppm. Includes adding phosphite ester to the process fluid.

[Dispersant]
The dispersant that can be used in the stain prevention method of the present disclosure is an succinimide compound that can be used as a stain prevention dispersant for a petroleum process or a heat exchanger of a petroleum process.

The succinimide compound has at least one of an alkenyl group and an alkyl group in one or more embodiments.

The succinate imide compound having an alkenyl group includes, in one or more embodiments, a succinate imide compound in which at least one carbon atom of the succinate imide group is substituted with a long chain alkenyl group, and at least one of the succinate imide groups. A succinate imide compound in which one carbon atom is substituted with a long chain alkenyl group and the nitrogen atom of the succinate imide group is substituted with an alkyleneimine group or an aminoalkylene group, respectively. Examples thereof include a succinate imide compound in which the nitrogen atom of the above is bonded via a hydrocarbon chain or a nitrogen-containing hydrocarbon chain. Examples of the long chain alkenyl group include alkenyl groups having 8 or more carbon atoms, 9 or more, 10 or more, 12 or more, 15 or more or 16 or more carbon atoms in one or more embodiments. Examples of the hydrocarbon chain include linear alkylene groups having 2 or more, 4 or more, 10 or more, 12 or more, 15 or more, or 16 or more carbon atoms. Examples of the nitrogen-containing hydrocarbon chain include a divalent substituent having 1 or more or 2 or more nitrogen atoms and 2 or more, 4 or more, 10 or more, 12 or more, 15 or more or 16 or more carbon atoms. Examples of the nitrogen-containing hydrocarbon chain include a diethylene amino group and an ethylene polyethyleneimine group.

Examples of the succinate imide compound having an alkyl group include, in one or more embodiments, a succinate imide compound in which at least one carbon atom of the succinate imide group is substituted with a long-chain alkyl group, and at least one of the succinate imide groups. A succinate imide compound in which one carbon atom is substituted with a long-chain alkyl group and the nitrogen atom of the succinate imide group is substituted with an alkyleneimine group or an aminoalkylene group, respectively. Examples thereof include succinateimide compounds in which the nitrogen atoms of the above are bonded via a hydrocarbon chain or a nitrogen-containing hydrocarbon chain. Examples of the long-chain alkyl group include alkyl groups having 8 or more carbon atoms, 9 or more, 10 or more, 12 or more, 15 or more, or 16 or more carbon atoms in one or more embodiments.

Examples of the succinimide compound having at least one of an alkenyl group and an alkyl group include compounds represented by the following formulas (V) to (VIII) in one or more embodiments.

In the formula (V), R ²¹ and R ²² represent an alkyl group having a number average molecular weight of 300 or more and 7,000 or less, or an alkenyl group having a number average molecular weight of 300 or more and 7,000 or less, and n represents an integer of 0 to 8. R ²¹ and R ²² may be the same as or different from each other.

In the formula (VI), R ²³ represents an alkyl group having a number average molecular weight of 300 or more and 7,000 or less, or an alkenyl group having a number average molecular weight of 300 or more and 7,000 or less, and m represents an integer of 0 to 8.

In formula (VII), R ²⁴ , R ²⁶ and R ²⁷ represent an alkyl group having a number average molecular weight of 300 or more and 7,000 or less, or an alkenyl group having a number average molecular weight of 300 or more and 7,000 or less, and R ²⁵ has 1 to 5 carbon atoms. It is an alkylene group of. R ²⁶ and R ²⁷ may be the same or different from each other.

In the formula (VIII), R ²⁸ represents an alkyl group having a number average molecular weight of 300 or more and 7,000 or less, or an alkenyl group having a number average molecular weight of 300 or more and 7,000 or less, and R ²⁹ is an alkylene group having 1 to 5 carbon atoms.

The number average molecular weight of the alkyl group and the alkenyl group is 500 or more and 5000 or less, 500 or more and less than 5000, 500 or more and 4000 or less, 700 or more and 4000 or less, or 800 or more and 3500 or less in one or more embodiments.

The alkyl and alkenyl groups may be straight or branched in one or more embodiments. Examples of R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁸ include a polyethylene group, a polyisopropyl group, a polyisoprene group, a polybutene group, a polyisobutene group, a polybutenyl group, a polyisobutenyl group and the like in one or more embodiments. Examples thereof include a polybutenyl group and a polyisobutenyl group.

Examples of R ²⁵ and R ²⁹ include a methylene group, an ethylene group, a propyl group, an isopropyl group and the like in one or more embodiments.

n and m are 0, 1, 2, 3, or 4 in one or more embodiments. "-CH ₂ CH _2- [NHCH ₂ CH ₂ ] _n- " in the formula (V) and "-CH ₂ CH _2- [NHCH ₂ CH ₂ ] _m- " in the formula (VI) are ethylene groups and diethylene. Examples thereof include an amino group and an ethylene polyethyleneimine group.

The succinimide compound may be used alone or in combination of a plurality of types in one or more embodiments.

The weight average molecular weight of the succinimide compound that can be used in the stain prevention method of the present disclosure is 3,000 to 15,000, or 5,000 to 12,000 in one or more embodiments. The weight average molecular weight of the dispersant is by size exclusion chromatography and can be specifically measured by the method described in Examples.

The concentration of the succinimide compound (the total when a plurality of types of succinimide compounds are used) in the process fluid supplied to the heat exchanger is 1 to 100 ppm, 2 to 80 ppm in one or more embodiments. , Or 3 to 50 ppm. The stain prevention method of the present disclosure disperses in the process fluid so that the dispersant in the process fluid supplied to the heat exchanger is 1 to 100 ppm, 2 to 80 ppm, or 3 to 50 ppm in one or more embodiments. Including adding an agent.

The content (ppm) of the phosphite ester compound (the total when using multiple types of phosphite ester compounds) and the succinimide compound (multiple types of succinimide) in the process fluid supplied to the heat exchanger. The ratio of the compound to the content (ppm) of the compound used is 5: 1 to 1: 5, 3: 1 to 1: 3, or 2: 1 to 2: 1 to 1: 3 in one or more embodiments. 1: 2 can be mentioned. In one or more embodiments, the antifouling method of the present disclosure comprises the content (ppm) of the phosphite ester compound and the content (ppm) of the succinimide compound in the process fluid supplied to the heat exchanger. Add the phosphite ester compound and the succinimide compound to the process fluid so that the ratio is 5: 1 to 1: 5, 3: 1 to 1: 3, or 2: 1 to 1: 2. include.

In one or more embodiments, the stain-preventing method of the present disclosure stores a stain-preventing agent (a stain-preventing agent containing the phosphite ester compound and the succinimide compound) used in the stain-preventing method of the present disclosure. Even if the material of the storage tank and / or the chemical injection equipment that injects the antifouling agent into the process fluid is an iron-based material such as carbon steel, which has lower corrosion resistance than stainless steel, the storage tank and the chemical injection equipment become dirty. Corrosion caused by the inhibitor can be suppressed. Further, since these storage tanks and chemical injection equipment are arranged near the heat exchanger near the injection point of the antifouling agent, they are exposed to high temperature, for example, 100 ° C. or higher or 140 ° C. or higher. However, according to the stain prevention method of the present disclosure, even when the storage tank and the chemical injection equipment are exposed to a high temperature, corrosion of the storage tank and the chemical injection equipment due to the stain preventive agent can be suppressed. Thus, the antifouling method of the present disclosure comprises, in one or more embodiments, adding a phosphite ester compound and / or a dispersant stored in a carbon steel storage tank to the process fluid. The antifouling method of the present disclosure comprises, in one or more embodiments, adding a phosphite ester compound and / or a dispersant to the process fluid using a carbon steel chemical injection facility.

The place where the phosphite ester compound and the dispersant are added to the process fluid is not particularly limited, and in one or more embodiments, the phosphite ester compound and the dispersant having the above concentrations are heat exchanges to be protected from fouling. The place where it can be introduced into the vessel is mentioned, or the front of the target heat exchanger is mentioned. The order of addition of the phosphite ester compound and the dispersant is not particularly limited, and in one or more embodiments, they may be added simultaneously, separately, or at different locations.
The phosphite ester compound and the dispersant may be added continuously or intermittently in one or more embodiments.

FIG. 1 is a block diagram showing an example of an oil refining processing apparatus provided with an atmospheric distillation column. In this petroleum refining processing apparatus, the crude oil supplied via the pump 6 is desalted by the desalting apparatus 1, then heated to 150 to 180 ° C. by the preheating exchange 2 (heat exchanger 2), and further preheated. It is introduced into 3 (heat exchanger 3), heated to 240 to 280 ° C., heated to 350 to 380 ° C. in the heating furnace 4, and introduced into the atmospheric distillation column 5. The canned liquid is sent from the bottom of the atmospheric distillation column 5 to the heat exchangers 3 and 2 via the pump 7 as a heat source.

When the stain prevention method of the present disclosure is performed in the heat exchanger 3 of the petroleum process of FIG. 1, the place where the phosphite ester compound and the dispersant are added is not limited in one or more embodiments of the heat exchanger 3. The place indicated by the arrow A in FIG. 1 in the foreground can be mentioned, but the place indicated by the arrow C in the foreground may be used. In the heat exchanger 3 of FIG. 1, when the stain prevention method of the present disclosure is performed on the heating side, the place where the phosphite ester compound and the dispersant are added is not limited in one or more embodiments. The place indicated by the arrow B in FIG. 1 in front of the above can be mentioned. The place where the phosphite ester compound and the dispersant are added in the present disclosure is not limited to the above-mentioned place, for example, in front of the desalting apparatus 1 (for example, in front of the heat exchanger arranged in front of the desalting apparatus 1). It may be.

[Anti-staining agent]
The present disclosure relates, in one aspect, to an antifouling agent for use in the antifouling method of the present disclosure. The antifouling agent of the present disclosure contains a phosphite ester and a dispersant, and the dispersant is a succinimide compound. In one or more embodiments, the antifouling agent may be a solid such as a powder or a tablet, or may be dissolved in a solvent, that is, a concentrated solution.
The phosphite ester and succinimide compound in the antifouling agent of the present disclosure are as described above.

[use]
The present disclosure relates, in one aspect, to the use of phosphite ester compounds in the antifouling methods of the present disclosure. The present disclosure also relates to the use of phosphite ester compounds in other embodiments to prevent fouling of heat exchangers in petroleum processes through which process fluids to which a dispersant, which is an succinimide compound, has been added. .. The phosphite ester compound and the succinimide compound are as described above.

The present disclosure may relate to one or more embodiments:
[1] A method for preventing heat exchangers from becoming dirty in the petroleum process.
It involves adding a phosphite ester compound and a dispersant to the process fluid passing through the heat exchanger.
A method for preventing stains, wherein the dispersant is an succinimide compound.
[2] The stain prevention method according to [1], wherein the imide compound is a succinimide having at least one of an alkenyl group and an alkyl group.
[3] The sub-phosphate compound and the succinimide compound in the process fluid supplied to the heat exchanger have a content (ppm) ratio of 5: 1 to 1: 5. The antifouling method according to [1] or [2], which comprises adding the phosphoester compound and the succinimide compound to the process fluid.
[4] From [1], which comprises adding the phosphite ester compound to the process fluid so that the concentration of the phosphite ester compound in the process fluid supplied to the heat exchanger is 1 to 100 ppm. The stain prevention method according to any one of [3].
[5] The dispersant of [1] to [4], which comprises adding the dispersant to the process fluid so that the concentration of the succinimide compound in the process fluid supplied to the heat exchanger is 1 to 100 ppm. The stain prevention method described in either.
[6] An antifouling agent for use in the antifouling method according to any one of [1] to [5], which contains a phosphite ester compound and a dispersant.
An antifouling agent in which the dispersant is an succinimide compound.
[7] Use of a phosphite ester compound to prevent contamination of the heat exchanger of a petroleum process through which a process fluid to which a dispersant which is an succinimide compound is added passes.

The present disclosure will be described based on the following examples and comparative examples, but the present disclosure is not limited thereto.

[Drug]
Phosphite ester 1: Phosphite ester compound represented by formula (I) Phosphite ester 2: Phosphite ester compound represented by formula (I) different from phosphite ester 1 Succinic acid imide 1 : Phosphite imide compound represented by the formula (V), molecular weight 10,000
Succinimide 2: Succinimide compound represented by the formula (V), molecular weight 6,000
Succinate: Polyalkenyl-substituted succinate compound, molecular weight 10,000
Polyolefin maleic anhydride copolymer (polyolefin ester): molecular weight 10,000

The molecular weight of the above compounds is the weight average molecular weight and can be measured by size exclusion chromatography. The measurement conditions are as follows.
Measurement conditions Column: Styrene-divinylbenzene cross-linked gel Eluent: Tetrahydrofuran Flow rate: 0.7 ml / min
Column temperature: 40 ° C

[Drug preparation]
The phosphite ester 1 or 2 is 10% by weight, and the ratio (weight ratio) of the phosphite ester 1 or 2 to the dispersant shown in Table 1 is 1: 3 as the amount of the active ingredient. Was mixed to prepare a drug.

[Anti-corrosion effect confirmation test 1]
Using a test piece made of carbon steel (SPCC), an anticorrosion effect confirmation test was conducted according to the following procedure.
An oxidation stability tester, a set of cylinders, and a set of test containers described in the oxidation stability test method of JIS K2276 (petroleum product-aviation fuel oil test method) were used.
First, 100 ml of the following drug was placed in a glass test container. After degreasing with acetone and drying, the test piece whose pre-weight was measured was placed in a test container, covered, and the test container was placed in a cylinder. Then, in order to replace the oxygen in the cylinder with nitrogen, the operation of injecting nitrogen at 0.5 MPa and opening the cylinder was repeated three times, and the third time, the cylinder was sealed with nitrogen press-fitted. A cylinder after nitrogen substitution was placed in an oxidation stability tester and allowed to stand in a constant temperature bath at 190 ° C. for 3 days.

[evaluation]
After the test is completed, the test piece is collected, red rust is removed with 15% hydrochloric acid aqueous solution and tap water, and the degree of corrosion (mdd) and the degree of erosion (mm / y) are calculated from the following formulas based on the weight difference of the test piece before and after the test. Calculated. The results are shown in Table 1 below.
Corrosion degree (mdd) = (M _1- M ₂ ) / (S × T)
Degree of erosion (mm / y) = mdd × {365 × 10 ^-4 } / d
M ₁ : Weight of test piece before test (mg)
M ₂ : Weight of test piece after test (mg)
S: Surface area of test piece (dm ² )
T: Number of test days d: Density of test piece (g / cm ³ )

As shown in Table 1, succinimide ester and succinimide 1 (a succinimide compound in which the nitrogen atoms of two alkenyl group-substituted succinimides represented by the formula (V) are bonded via ethylene alkyleneimine). In Examples 1 and 2 in which the above was used in combination, almost no corrosion of carbon steel was confirmed.

[Dirt (fouling) prevention test]
The stain (fouling) prevention test is a test for investigating the stain prevention effect of the oil refining stain inhibitor, and the heating tube (heat rod) 21 shown in FIG. 2 is used as a test member for adhering stains. It is carried out by bringing the heating tube into contact with oil and measuring the state of adhesion of the dirt. This heating tube 21 is used for a thermal stability tester specified in JIS K2276, and is made of mild steel and has a constricted portion having a large diameter at the

ends

21a and 21b and a small diameter at the intermediate portion 21c. It has a tube shape. The heating tube 21 is inserted into the tube-shaped heating tube cage 22 shown in FIG. An inflow pipe 23a and an outflow pipe 23b are connected to the upper part and the lower part of the heating pipe cage 22, and a thermocouple 24 is inserted in the central part of the heating pipe 21. It is possible to pass an electric current from both

portions

21a and 21b of the heating tube 21 so that the temperature sensed by the thermocouple 24 becomes a predetermined temperature. As the test apparatus, a HotLiquid Process Simulator tester manufactured by Alcoa Co., Ltd. equipped with the above-mentioned heating tube 21 was used.

The heating tube 21 was heated by the test apparatus under the following conditions, and a sample was introduced from the inflow tube 23a to perform the test.
Sample: Prepared by adding to crude oils 1 and 2 having different asphaltene contents so that the concentrations of the phosphite ester compound and the dispersant shown in Table 2 below were 10 ppm and 20 ppm, respectively.
Crude oil 1: Asphaltene content 0.5% by weight or less Crude oil 2: Asphaltene content 2.0 to 3.0% by weight or less Temperature of heating tube 21: 330 to 340 ° C (heated over 20 minutes)
Tank, line, pump temperature: 100 ° C
Sample amount: 500 ml (Since it is partitioned in the tank, the returned sample is not mixed)
Sample introduction flow rate: 1 ml / min System pressure: 500-600 psi (pressure adjusted with nitrogen)
Test time: 5 hours

The stain prevention effect was evaluated according to the following evaluation criteria based on the sample outlet temperature change (Δt). The results are shown in Table 2 below.
[Sample outlet temperature change: Δt]
The sample temperature at the maximum temperature after the start of the test in the outflow pipe 23b (outlet of the heating section) and the temperature change (Δt) of the sample temperature after 5 hours were measured. The more dirt adheres to the heating tube 21, the larger Δt becomes.
Evaluation Criteria A: Δt is 5 or less B: Δt is more than 5 and less than 8 C: Δt is 8 or more and less than 15 D: Δt is 15 or more

As shown in Table 2, in Example 3 in which the phosphite ester and the succinimide 1 were used in combination, the adhesion of stains could be suppressed regardless of the asphaltene content of the crude oil. That is, it was confirmed that the combined use of the phosphite ester and the succinimide compound can sufficiently prevent the heat exchanger from becoming dirty in the petroleum process.

[Anti-corrosion effect confirmation test 2]
Anticorrosion effect confirmation test 1 except that the blending ratio of phosphite ester 1 and succinimide 1 (succinimide compound represented by the formula (V), molecular weight: 10,000) is as shown in Table 3 below. The test and evaluation were carried out in the same manner as above. The results are shown in Table 3 below.

As shown in Table 3, almost no corrosion of carbon steel was confirmed regardless of the blending ratio.

[Anti-corrosion effect confirmation test 3]
The tests and evaluations were carried out in the same manner as in the anticorrosion effect confirmation test 1 except that succinimide 2 (succinimide compound represented by the formula (V), molecular weight: 6,000) was used as the dispersant. Blending ratio (weight ratio) of phosphoester 1 and succinimide 2: 1: 3).
As a result, no corrosion of carbon steel was confirmed (mm / y: 0.01).

Claims

A method of preventing heat exchanger stains in the petroleum process.
It involves adding a phosphite ester compound and a dispersant to the process fluid passing through the heat exchanger.
A method for preventing stains, wherein the dispersant is an succinimide compound.
The stain prevention method according to claim 1, wherein the succinimide compound is an succinimide having at least one of an alkenyl group and an alkyl group.
The phosphite ester so that the ratio of the content (ppm) of the phosphite ester compound to the succinimide compound in the process fluid supplied to the heat exchanger is 5: 1 to 1: 5. The antifouling method according to claim 1 or 2, which comprises adding the compound and the succinimide compound to the process fluid.
Any of claims 1 to 3, wherein the phosphite ester compound is added to the process fluid so that the concentration of the phosphite ester compound in the process fluid supplied to the heat exchanger is 1 to 100 ppm. Dirt prevention method described in Crab.
The invention according to any one of claims 1 to 4, wherein the dispersant is added to the process fluid so that the concentration of the succinimide compound in the process fluid supplied to the heat exchanger is 1 to 100 ppm. Dirt prevention method.
An antifouling agent for use in the antifouling method according to any one of claims 1 to 5, which contains a phosphite ester compound and a dispersant.
An antifouling agent in which the dispersant is an succinimide compound.
Use of a phosphite ester compound to prevent contamination of the heat exchanger of the petroleum process through which the process fluid to which the dispersant, which is an succinimide compound, is added.