JP6485598B1 - Methods for preventing contamination of heat exchangers in petroleum processes. - Google Patents

Abstract

Provided is a method for preventing contamination of a heat exchanger in an oil process. The present invention relates to a method for preventing fouling of a heat exchanger in a petroleum process, the method comprising adding a phosphite compound and a dispersant to a process fluid passing through the heat exchanger.

Description

  The present disclosure relates to a method for preventing fouling of heat exchangers in petroleum processes.

  In the distillation process of an oil refinery 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 to perform a distillation operation. Crude oil receives a heat history in the heat exchanger and heating furnace, and a large amount of dirt adheres. As one form of the soil component, there is a form in which an organic polymer component called asphaltenes is mixed. The adhesion of dirt causes a decrease in the heat exchange rate of the heat exchanger and the heating furnace, resulting in an increase in the amount of fuel used to maintain the outlet temperature.

  Patent Document 1 discloses a heat exchanger to be added to a process fluid before a desalter, a stain preventing agent for a heating furnace, and a stain preventing method. Further, Patent Document 2 discloses a method for preventing a preheated asphaltene-derived soil in a petroleum process using a phosphate ester anticorrosive and a dispersant.

JP 2010-163539 A WO2015 / 022979

  The present inventor has found that phosphate-based anticorrosives are particularly useful for preventing asphaltene-derived stains during preheating (Patent Document 2). However, when phosphoric acid esters are used in place of conventional antifouling agents, corrosion by phosphoric acid esters occurs in carbon steel and stainless steel used in storage tanks and chemical injection facilities for general antifouling agents. There was a problem. In particular, the corrosivity of the phosphate ester becomes more significant as the temperature of the phosphate ester increases. The higher the injection point, the temperature of the phosphate ester rises to about 200 ° C. For this reason, the conventional chemical injection equipment cannot withstand the corrosion of phosphate esters, and there is a problem that the material of the chemical injection equipment must be changed to a corrosion resistant material.

  In one aspect, the present disclosure provides a new method that can prevent heat exchanger fouling in a petroleum process.

  In one aspect, the present disclosure provides a method for preventing fouling of a heat exchanger in a petroleum process, the method comprising adding a phosphite compound and a dispersant to a process fluid passing through the heat exchanger. Regarding the method.

  In another aspect, the present disclosure relates to an antifouling agent for use in the antifouling method of the present disclosure, the antifouling agent containing a phosphite compound and a dispersant.

  According to the present disclosure, contamination of the heat exchanger in the petroleum process can be suppressed. According to the present disclosure, in one or a plurality of embodiments, corrosion of the storage tank of the antifouling agent and the chemical injection facility can be suppressed.

FIG. 1 is a block diagram illustrating an example of an oil refining treatment apparatus including an atmospheric distillation column. FIG. 2 is a cross-sectional view of the heating tube used in the dirt prevention test. FIG. 3 is a cross-sectional view of the heating tube inserted into the heating tube holder.

  The present disclosure is based on the finding that fouling in a heat exchanger such as preheating exchange in a petroleum process can be prevented by using a phosphite compound and a dispersant in combination. Moreover, this indication can reduce the corrosion of the chemical injection equipment produced when a phosphate ester type anticorrosive is used as an antifouling agent by using a phosphite compound instead of the phosphate ester type anticorrosive. Based on this knowledge.

  According to the present disclosure, in one or a plurality of embodiments, contamination of a heat exchanger such as preheating exchange in an oil process can be prevented, and preferably, the heat exchange rate of the heat exchanger can be improved / maintained. Cleaning costs can be reduced. Moreover, according to this indication, in one or some embodiment, the conventional chemical injection equipment can be used, without changing a chemical injection equipment, and the contamination in the heat exchanger of a petroleum process can be prevented.

  In the method for preventing fouling of the present disclosure, details that can prevent fouling in a heat exchanger, particularly preheating, are not clear, but the mechanism is estimated as follows. That is, as one of the causes of contamination, sulfur atoms of asphaltenes may be deposited by forming sulfides on the surface of the heat exchanger. However, when a phosphite compound and a dispersant are added, phosphorous acid is added. It is considered that a film of the acid ester compound and / or the phosphite compound decomposed at high temperature is formed on the surface of the heat exchanger, and this film can suppress the formation of sulfide on the surface of the heat exchanger. However, the present disclosure may not be limited to these ideas.

  In the present disclosure, the “petroleum process” refers to all or part of the process from the production of hydrocarbons such as crude oil to the production of various petroleum products. In one or a plurality of embodiments, the petroleum process heats hydrocarbons such as crude oil, and uses the difference in boiling points of these heated hydrocarbons in an atmospheric distillation apparatus to use volatile oil and light oil such as LPG and naphtha. And the like. The petroleum process in the present disclosure may include an oil refining process in one or more embodiments.

In the dirt prevention method of the present disclosure, the “heat exchanger” is a heat exchanger used in a petroleum process. Examples of the heat exchanger include, but are not limited to, preheating exchange (also referred to as preheating heat exchange or preheating exchanger), a preheater, a reboiler, and the like. In these heat exchangers, it is particularly high temperature portions of about 200 ° C. or more that are easily contaminated and accumulated. In one or a plurality of embodiments, the dirt prevention method of the present disclosure has a high temperature portion that is about 200 ° C., for example, 180 ° C. or higher, 190 ° C. or higher, 200 ° C. or higher, 210 ° C. or higher, or 220 ° C. or higher during processing. This is a method for preventing contamination of a heat exchanger. In one or a plurality of embodiments, the contamination prevention method of the present disclosure exhibits the contamination prevention effect more effectively at about 200 ° C. or more.
In one or a plurality of embodiments, the heat exchanger in the oil process includes a heat exchanger in the oil refining process, a preheating exchange in the oil process, and the like.

  In the present disclosure, “process fluid” refers to a liquid or gas provided in a petroleum process. Process fluids include, in one or more embodiments, crude oil or hydrocarbons derived therefrom that are processed in a petroleum process. In one or a plurality of embodiments that are not particularly limited, the process fluid includes a liquid supplied to the preheating exchange in the oil refining process, a liquid in the preheating exchange, or the like.

  In one or a plurality of non-limiting embodiments, the “stain” in the soil prevention method of the present disclosure refers to a material including asphaltene, or a soil including asphaltene that adheres and / or accumulates in a heat exchanger. Say. Therefore, the fouling prevention in the heat exchanger in the present disclosure is, in one or more embodiments, the suppression of asphaltene adhesion and / or accumulation in the heat exchanger.

[Stain prevention method]
In one aspect, the present disclosure provides a method for preventing fouling of a heat exchanger in a petroleum process, comprising adding a phosphite compound and a dispersant to a process fluid passing through the heat exchanger in the petroleum process (the present disclosure). Contamination prevention method).

[Phosphorous ester compound]
The phosphite compound used in the soil prevention method of the present disclosure includes, in one or more embodiments, a phosphite compound used in a petroleum process.

Examples of the phosphite compound include, but are not limited to, a phosphonic acid phosphite compound, a phosphite phosphite compound, and a diphosphite phosphite compound in one or more embodiments. . Examples of the phosphonic acid phosphite compound include phosphite compounds represented by the formula (I). Examples of the phosphite-type phosphite compound include phosphite compounds represented by the formula (II). Examples of the diphosphite-type phosphite compound include those containing two structures of the formula (II) in one or a plurality of embodiments, and dimers (dimers) of the compound of the formula (II). Examples of the diphosphite-type phosphite compound include compounds represented by formula (III) or (IV) in one or a plurality of embodiments.

In the formula (I), R ¹ and R ² are the same or different and are groups having 1 to 30 carbon atoms. In the formula (II), R ³ , R ⁴ and R ⁵ are the same or different and are groups having 1 to 30 carbon atoms. In the formula (III), R ⁶ , R ⁷ and R ⁸ are the same or different and are groups having 1 to 30 carbon atoms, and X ¹ is an oxygen atom or a carbon atom. In the formula (IV), R ⁹ and R ¹⁰ are the same or different and are groups having 1 to 30 carbon atoms, and X ² is a carbon atom.
In one or more embodiments, the group having 1 to 30 carbon atoms is an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 1 to 30 carbon atoms, or an aryl group having 6 to 30 carbon atoms. , An alkyl group having 7 to 30 carbon atoms, or an alkylaryl group having 7 to 30 carbon atoms. The alkyl group, alkenyl group, aryl group, aralkyl group, and alkylaryl group may have a substituent in one or more embodiments. In one or more embodiments, the alkyl group may be a linear alkyl group or a branched alkyl group.

In the formula (I), R ¹ and R ² may be the same or different, but it is preferable that R ¹ and R ² are the same. In the formula (II), R ³ , R ⁴ and R ⁵ may be the same or different, but it is preferable that R ³ , R ⁴ and R ⁵ are the same. In formula (III), R ⁶ and R ⁸ may be the same or different, but it is preferable that R ⁶ and R ⁸ are the same.

As a phosphite compound, in one or more embodiments,
Triphenyl phosphite, trisnonylphenyl phosphite, tricresyl phosphite, triethyl phosphite, tris (2-ethylhexyl) phosphite, tridecyl phosphite, trilauryl phosphite, tris (tridecyl) phosphite, trioleyl phosphite Phyto, tristearyl phosphite, diphenyl mono (2-ethylhexyl) phosphite, diphenyl monodecyl phosphite, diphenyl mono (tridecyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite;
Diethyl hydrogen phosphite, bis (2-ethylhexyl) hydrogen phosphite, dilauryl hydrogen phosphite, dioleyl hydrogen phosphite, diphenyl hydrogen phosphite;
Tetraphenyldipropylene glycol diphosphite, tetra (C12-15 alkyl) -4,4'-isopropylidene diphenyl diphosphite, bis (tridecyl) pentaerythritol diphosphite and bis (nonylphenyl) pentaerythritol diphosphite Bis (tridecyl) pentaerythritol diphosphite, bis (decyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite;
Examples thereof include tetraphenyl (tetratridecyl) pentaerythritol tetraphosphite, hydrogenated bisphenol A / pentaerythritol phosphite polymer, or a combination thereof.

  In one or a plurality of embodiments, the phosphite compound includes triphenyl phosphite, tris in order to prevent further contamination of heat exchangers in petroleum processes and / or to further prevent 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 Diphenyl mono (2-ethylhexyl) phosphite, diphenyl monodecyl phosphite, diphenyl mono (tridecyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, diethyl hydrogen phosphite Ito, bis (2-ethylhexyl) hydrogen phosphite, dilauryl hydrogen phosphite, dioleyl hydrogen phosphite, diphenyl hydrogen phosphite or a combination thereof are preferred. From the same viewpoint, the phosphite compound is preferably a phosphonic acid type phosphite compound, diethyl hydrogen phosphite, bis (2-ethylhexyl) hydrogen phosphite, dilauryl hydrogen phosphite, dioleyl hydrogen phosphite. Diphenyl hydrogen phosphite or a combination thereof is more preferable.

  In one or a plurality of embodiments, the phosphite compound may be used alone or in combination.

  The concentration of the phosphite compound in the process fluid supplied to the heat exchanger includes 1 to 100 ppm, 2 to 80 ppm, or 3 to 50 ppm in one or more embodiments. In one or a plurality of embodiments, the soil prevention method of the present disclosure is such that the concentration of phosphite in the process fluid supplied to the heat exchanger is 1 to 100 ppm, 2 to 80 ppm, or 3 to 50 ppm. Adding a phosphite to the process fluid.

[Dispersant]
Dispersing agents that can be used in the soil prevention method of the present disclosure include those that are conventionally used or can be used in the future as soil prevention for petroleum processes or petroleum process heat exchangers. Dispersants that can be used in the antifouling method of the present disclosure include, in one or more non-limiting embodiments, polyolefin esters, polyalkenyl-substituted succinates, or combinations thereof.

  The concentration of the dispersant in the process fluid supplied to the heat exchanger includes 1 to 100 ppm, 2 to 80 ppm, or 3 to 50 ppm in one or more embodiments. In one or a plurality of embodiments, the dirt prevention method of the present disclosure is dispersed in the process fluid such 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. Adding the agent.

  The ratio of the content (ppm) of the phosphite compound and the dispersant in the process fluid supplied to the heat exchanger may be 5: 1 to 1: 5, 3: 1 to 1 in one or more embodiments. : 3, or 2: 1 to 1: 2. In one or a plurality of embodiments, the contamination prevention method of the present disclosure has a ratio of the content (ppm) of the phosphite compound and the dispersant in the process fluid supplied to the heat exchanger of 5: 1 to 1: Adding a phosphite compound and a dispersant to the process fluid to be 5, 3: 1 to 1: 3, or 2: 1 to 1: 2.

  The place where the phosphite compound and the dispersant are added to the process fluid is not particularly limited. In one or a plurality of embodiments, the phosphite compound and the dispersant having the above-described concentrations are heat exchange targets to prevent contamination. The place where the heat exchanger can be introduced is mentioned, or in front of the target heat exchanger. The order of addition of the phosphite compound and the dispersant is not particularly limited, and in one or a plurality of embodiments, they may be added simultaneously, separately, or in different places.

  FIG. 1 is a block diagram illustrating an example of an oil refining treatment apparatus including an atmospheric distillation column. In this oil refining treatment apparatus, the crude oil supplied via the pump 6 is desalted by the desalting apparatus 1 and then heated to 150 to 180 ° C. by the preheating exchanger 2 (heat exchanger 2), and further preheated. 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 bottoms from the bottom of the atmospheric distillation column 5 is sent as a heat source to the heat exchangers 3 and 2 via the pump 7.

  When performing the soil prevention method of the present disclosure in the heat exchanger 3 of the petroleum process of FIG. 1, the addition site of the phosphite compound and the dispersant is not limited, and in one or a plurality of embodiments, the heat exchanger 3 A location indicated by an arrow A in FIG. 1 that is in front is mentioned, but a location indicated by an arrow C in front is also possible. In the heat exchanger 3 of FIG. 1, when the soil prevention method of the present disclosure is performed on the heating side, the addition site of the phosphite compound and the dispersant is not limited, and in one or more embodiments, the heat exchanger 3 A place indicated by an arrow B in FIG.

[Anti-fouling agent]
In one aspect, the present disclosure relates to an antifouling agent for use in the antifouling method of the present disclosure, the antifouling agent containing a phosphite and a dispersant. In one or a plurality of embodiments, the form of the antifouling agent of this aspect may be a solid such as a powder or a tablet, or may be dissolved in a solvent, that is, in the form of a concentrated liquid.

[use]
In one aspect, the present disclosure relates to the use of a phosphite compound in a soil prevention method of the present disclosure. The present disclosure, in another aspect, also relates to the use of a phosphite compound to prevent fouling of a petroleum process heat exchanger through which a process fluid to which a dispersant has been added passes. The phosphite compound is as described above.

The present disclosure may relate to one or more of the following embodiments;
[1] A method for preventing contamination of a heat exchanger in an oil process,
A method for preventing soiling, comprising adding a phosphite compound and a dispersant to a process fluid passing through the heat exchanger.
[2] The method according to [1], including adding the phosphite compound to the process fluid such that the concentration of the phosphite compound in the process fluid supplied to the heat exchanger is 1 to 100 ppm. Dirt prevention method.
[3] The method according to [1] or [2], comprising adding the dispersant to the process fluid such that the concentration of the dispersant in the process fluid supplied to the heat exchanger is 1 to 100 ppm. Dirt prevention method.
[4] The ratio (phosphite compound: dispersant) of the content (ppm) of the phosphite compound and the dispersant in the process fluid supplied to the heat exchanger is 5: 1 to 1: 5 The soil prevention method according to any one of [1] to [3], comprising adding the phosphite compound and the dispersant to the process fluid.
[5] The contamination prevention method according to any one of [1] to [4], wherein the contamination prevention includes suppressing adhesion and / or accumulation of asphaltene in the heat exchanger.
[6] An antifouling agent for use in the antifouling method according to any one of [1] to [5], comprising an phosphite compound and a dispersant.
[7] Use of a phosphite compound for preventing fouling of a heat exchanger of a petroleum process through which a process fluid to which a dispersant has been added passes.

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

[Test piece]
The following two types of test pieces were prepared.
Carbon steel: 10 mm x 60 mm x 1 mm, SPCC, 7.85 g / cm ³
Stainless steel: 10 mm × 60 mm × 1 mm, SUS304, 7.93 g / cm ³

[Drug]
The following drugs were prepared.
Phosphite Compound A: Phosphite A (phosphonic acid type phosphite compound) and a dispersant Phosphite Compound B: Phosphite B (phosphonic acid type phosphorous) Acid ester compound) and a dispersing agent Phosphite compounded product C: Phosphite ester compound C (phosphorous acid type phosphite compound) and a dispersing agent Phosphite compounded product D: Phosphorus ester compound E containing phosphoric acid ester D (phosphorous acid type phosphorous acid ester compound) and dispersant Phosphite ester A (phosphonic acid type phosphorous acid ester compound) and phosphorous acid Phosphoric acid ester compound containing ester C (phosphorous acid type phosphorous acid ester compound) and dispersant: Phosphoric acid ester A and sublimation containing phosphoric acid ester and dispersing agent used as anticorrosive for high temperature phosphoric acid Ester B, and phosphite C and phosphite D are different phosphite compound. A polyolefin ester was used as the dispersant.
<Method for preparing compounded product>
Each of the blended products A to D was adjusted so that the above-mentioned phosphite ester or phosphate ester and the dispersant were 30% by weight in a ratio of 1: 1 (weight ratio) using heavy aromatic naphtha as a solvent. did. The phosphite compound E was adjusted so that an equal amount mixture of the phosphite A and phosphite C and the dispersant were each 30% by weight in a ratio of 1: 1 (weight ratio).

[Anti-corrosion effect confirmation test 1]
Using a carbon steel test piece, the anticorrosion effect confirmation test was performed according to the following procedure. First, 100 ml of the drug shown in Table 1 below was placed in a 100 ml screw tube. After degreasing and drying with acetone, the test piece whose pre-weight was measured was put into a screw tube, covered, and allowed to stand in a thermostatic bath at 50 ° C. for 7 days.

[Evaluation]
After completion of the test, the test piece is collected, red rust is removed with a 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 between 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 : Mass of test piece before test (mg)
M ₂ : Mass after test of test piece (mg)
S: Test piece surface area (dm ² )
T: Test days d: Test piece density (g / cm ³ )

  As shown in Table 1, in Comparative Example 1 using the phosphate ester compounded product, corrosion of the carbon steel occurred. On the other hand, no corrosion of carbon steel was confirmed in Examples 1 to 5 using the phosphite compound.

[Anti-corrosion effect confirmation test 2]
Using a test piece made of stainless steel, the anticorrosion effect confirmation test was performed according to the following procedure.
In order to perform the test at 150 ° C., 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 and drying with acetone, put the test piece with the pre-weighed weight in the test container and cover it. After putting in the cylinder, inject nitrogen at 0.5 MPa to replace oxygen in the cylinder with nitrogen. The opening operation was repeated three times, and the third time was sealed with nitrogen being injected. The cylinder after nitrogen substitution was put into the oxidation stability tester, and left still in a thermostatic bath at 150 ° C. for 3 days. After the test, the same evaluation as the anticorrosion effect confirmation test 1 was performed. The results are shown in Table 2 below.

  As shown in Table 2, corrosion of stainless steel occurred in Comparative Example 2 using the phosphate ester compounded product. On the other hand, in Examples 6 to 10 using the phosphite compound, no corrosion of stainless steel was confirmed.

[Fouling prevention test]
The dirt (fouling) prevention test is a test for examining the dirt prevention effect of the oil refining dirt prevention agent. As a test member for attaching dirt, a heating tube (heat rod) 21 shown in FIG. The heating tube is brought into contact with oil, and the adhesion state of the dirt is measured. This heating tube 21 is used for a thermal stability tester specified in JIS K2276, and is made of mild steel, with the end portions 21a and 21b having a large diameter and the intermediate portion 21c having a small diameter, which is constricted. It has a tube shape. The heating tube 21 is inserted into a tube-shaped heating tube holder 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 holder 22, and a thermocouple 24 is inserted in the center part of the heating pipe 21, and a thermoelectric generator is connected by a temperature controller (not shown). It is possible to allow current to flow from both portions 21a and 21b of the heating tube 21 so that the temperature sensed by the pair 24 becomes a predetermined temperature. As the test apparatus, a Hot Liquid Process Simulator tester manufactured by Alcor Corporation equipped with the heating tube 21 described above was used.

With the test apparatus, the heating tube 21 was heated under the following conditions, and the sample was introduced from the inflow tube 23a for testing.
Sample: The chemicals shown in Table 3 below were prepared by adding a dispersant and a concentration of a phosphite compound or a phosphate ester to a crude oil sample so that each concentration was 10 ppm.
Temperature of heating tube 21: 360 ° C. (heated to 360 ° C. over 20 minutes)
Tank, line, pump temperature: 100 ° C
Sample volume: 500 ml (returned sample is not mixed because it is partitioned in the tank) Sample introduction flow rate: 1 ml / min System pressure: 500 psi (pressure adjustment with nitrogen)
Test time: 5 hours

The antifouling effect was evaluated according to the following evaluation criteria based on the sample outlet temperature change (Δt). The results are shown in Table 3 below.
[Sample outlet temperature change: Δt]
The sample temperature at the maximum temperature after the start of the test at the outflow pipe 23b (heater outlet) and the temperature change (Δt) of the sample temperature after 5 hours were measured. Δt increases as dirt adheres to the heating tube 21.
Evaluation criteria A: Δt is less than 8
B: Δt is 8 or more and less than 15
C: Δt is 15 or more

  As shown in Table 3, Examples 11 and 12 using the phosphite compounded product were able to suppress the adhesion of dirt at the same level as in Reference Example 1 using the phosphate ester compounded product. That is, it was confirmed that the heat exchanger contamination in the petroleum process can be sufficiently prevented by using the phosphite ester and the dispersant in combination.

Claims (9)

A method for preventing asphaltene contamination of a heat exchanger in an oil process,
The process fluid passing through the heat exchanger, viewed including the addition of a phosphite compound and a dispersant,
The stain preventing method , wherein the phosphite compound is a phosphite compound represented by the formula (I) .

[In the formula (I), R ¹ and R ² are the same or different and are groups having 1 to 30 carbon atoms. ]   The soil prevention method according to claim 1, comprising adding the phosphite compound to the process fluid such that the concentration of the phosphite compound in the process fluid supplied to the heat exchanger is 1 to 100 ppm. Method.   The method for preventing fouling according to claim 1 or 2, comprising adding the dispersant to the process fluid such that the concentration of the dispersant in the process fluid supplied to the heat exchanger is 1 to 100 ppm.   The phosphite compound and the content of the phosphite compound and the dispersant (ppm) in the process fluid supplied to the heat exchanger are in the range of 5: 1 to 1: 5. 4. The method of preventing fouling according to any one of claims 1 to 3, comprising adding a dispersant to the process fluid.   The contamination prevention method according to any one of claims 1 to 4, wherein the contamination prevention includes suppressing adhesion and / or accumulation of asphaltene in a heat exchanger. A asphaltene antifoulant for use in fouling prevention method according to any one of claims 1 to 5, containing a phosphite compound and a dispersant,
An antifouling agent , wherein the phosphite compound is a phosphite compound represented by the formula (I) .

[In the formula (I), R ¹ and R ² are the same or different and are groups having 1 to 30 carbon atoms. ] For preventing heat exchanger asphaltene fouling petroleum processes dispersant passes the process fluid is added, to the use of phosphite compounds,
Use, wherein the phosphite compound is a phosphite compound represented by formula (I) .

[In the formula (I), R ¹ and R ² are the same or different and are groups having 1 to 30 carbon atoms. ] The phosphite compound is diethyl hydrogen phosphite, bis (2-ethylhexyl) hydrogen phosphite, dilauryl hydrogen phosphite, dioleyl hydrogen phosphite, diphenyl hydrogen phosphite or a combination thereof. 5. The method for preventing contamination according to any one of 5 above. The method for preventing soiling according to any one of claims 1 to 5 and 8, wherein the dispersant is a polyolefin ester, a polyalkenyl-substituted succinic acid ester, or a combination thereof.

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