Method for Supplying Chemicals in Petroleum Process

Abstract

To provide an agent supply method in a petroleum process that can efficiently prevent fouling and corrosion while suppressing corrosion in a subsequent facility in one aspect.SOLUTION: A method for supplying a surfactant to a distillation facility in a petroleum refining process in one aspect comprises monitoring operation of the distillation facility and controlling a supply rate of the surfactant according to a deposition location of at least one of an ammonium salt and an amine salt in the distillation facility predicted based on the monitoring, and the surfactant being an oil-soluble surfactant having a nitrogen-containing hydrophilic group.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure provides a method for supplying a surfactant to a distillation facility in an oil refining process, a method for suppressing the deposition of dirt caused by inorganic salts contained in crude oil in an oil refining process using the same, a method for suppressing corrosion of a distillation facility in an oil refining process using the same, and an automatic supply system for chemicals that can be used for them.

Background Art

[0002] In the oil refining process, various petroleum products such as naphtha, gasoline, kerosene, and gas oil are produced by refining crude oil. In recent years, the demand for fuel oil has been changing due to the progress of low fuel consumption technology for automobiles and the sulfur regulations for marine fuel oil by the International Maritime Organization (IMO). The demand for middle distillates such as gas oil has been increasing compared to the demand for low boiling point fractions such as gasoline, and the operation has shifted to an operation to increase the production volume of middle distillates. As an operation to increase the production volume of middle distillates, an operation to lower the top column temperature is generally performed. The precipitation of salts typified by ammonium chloride in the oil refining process is well known, and pressure loss occurs due to the obstruction of the process flow, resulting in a problem of reduced equipment usage efficiency. In addition, there is a problem that severe local corrosion occurs in the equipment due to the moisture absorption of the precipitated salt.

[0003] FCC (Fluid Catalytic Cracking) is a method for decomposing high boiling point fractions using a solid acid catalyst to produce high octane gasoline, aiming to convert heavy oil that has become excessive due to changes in the petroleum product demand composition into light oil, and to produce gasoline with high added value, middle distillates, and an LPG fraction containing a large amount of olefins from the feedstock for heavy oil evaluation.

[0004] In the petroleum refining process, fouling of equipment that can be caused by ammonium salts and the resulting corrosion are problems from the viewpoints of operational stability and ensuring profitability. As one of the solutions, there is a technique using β-hydroxyethyltrimethylammonium hydroxide (choline) (for example, Patent Document 1). The method of Patent Document 1 is a technique that solves the problem by reacting ammonium chloride, which can cause fouling and corrosion, with choline to form choline chloride.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years, the demand structure of petroleum products such as gasoline has been changing, and it has been required to flexibly and efficiently produce the necessary petroleum products according to the change in demand. For this reason, it is necessary to appropriately change the operating conditions in order to refine petroleum products according to the change in demand.

[0007] The frequency of fluctuations in operating conditions has increased, and as a result, the locations and amounts of substances that cause fouling and corrosion have changed, resulting in the problem of additional treatment costs. Therefore, from the viewpoint of reducing operating costs, it is required to accurately grasp the fouling and corrosion states that can occur in the equipment and supply an appropriate amount of chemicals to the necessary locations. In addition, in distillation towers such as the main tower of FCC, treatments are carried out to prevent fouling and corrosion by ammonium salts. However, in the case of the conventional technology, there is a problem that it is difficult to completely suppress corrosion because it does not have an anticorrosive effect.

[0008] In one aspect, the present disclosure provides a method for supplying a chemical agent capable of efficiently preventing fouling and corrosion while suppressing the deposition of fouling and corrosion in downstream equipment, and an automatic chemical agent supply system usable therefor.

Means for Solving the Problems

[0009] In one aspect, the present disclosure relates to a method for supplying a surfactant to distillation equipment in a petroleum refining process, comprising: monitoring the operation of the distillation equipment, and controlling the supply rate of the surfactant according to at least one deposition location of ammonium salts and amine salts in the distillation equipment predicted based on the monitoring, wherein the surfactant is an oil-soluble surfactant having a nitrogen-containing hydrophilic group.

[0010] In another aspect, the present disclosure relates to a method for suppressing the deposition of fouling caused by inorganic salts contained in crude oil in distillation equipment in a petroleum refining process, comprising: monitoring the operation of the distillation equipment, and controlling the supply rate of the surfactant according to at least one deposition location of ammonium salts and amine salts in the distillation equipment predicted based on the monitoring, wherein the surfactant is an oil-soluble surfactant having a nitrogen-containing hydrophilic group.

[0011] In another aspect, the present disclosure relates to a method for suppressing corrosion of distillation equipment in a petroleum refining process, comprising: monitoring the operation of the distillation equipment, controlling the supply rate of the surfactant according to at least one deposition location of ammonium salts and amine salts in the distillation equipment predicted based on the monitoring, wherein the surfactant is an oil-soluble surfactant having a nitrogen-containing hydrophilic group.

[0012] The present disclosure, in other aspects, relates to an automatic supply system for a chemical agent for suppressing the deposition of dirt caused by inorganic salts contained in crude oil in distillation equipment in an oil refining process, a supply line for supplying the chemical agent to the distillation equipment and a monitoring unit for monitoring the operation of the distillation equipment, and a control unit for controlling the supply rate of the chemical agent through the supply line. The control unit is configured to predict at least one deposition location of ammonium salts and amine salts based on the monitoring result in the monitoring unit, and accordingly control the supply of the chemical agent through the supply line. The present disclosure relates to a system.

Advantages of the Invention

[0013] According to the present disclosure, in one aspect, it is possible to provide a method for supplying a chemical agent that can efficiently prevent dirt and corrosion while suppressing corrosion in subsequent equipment, and an automatic supply system for the chemical agent that can be used therefor.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0015] In the petroleum refining process of crude oil refineries and the like, raw materials such as crude oil are heated to a predetermined temperature or higher and separated into various fractions in a distillation column according to the boiling point range. For example, if the operating conditions are changed so as to reduce the production volume of petroleum products with a low boiling point range and increase the production volume of petroleum products with a high boiling point range due to changes in the demand structure of petroleum products, fouling different from normal operating conditions and corrosion caused thereby may occur. Ammonium chloride is known as one of the substances that cause this. There is a report that the salt formation temperature (calculated value) of ammonium chloride is about 74 °C, but this is only a calculated value and varies depending on the type of equipment and the like. Also, even in the same equipment, the salt formation temperature of ammonium chloride varies depending on changes in operating conditions such as the origin and properties of the crude oil used as the raw material, and changes in the concentrations of various components in the process fluid resulting from such changes. The inventors of the present invention have found that by predicting fluctuations in the deposition locations of ammonium salts / amine salts that can cause fouling and controlling the chemical supply amount accordingly, fouling and corrosion can be efficiently suppressed. Furthermore, the inventors of the present invention have found that by using an oil-soluble surfactant having a nitrogen-containing hydrophilic group as the chemical to be supplied, fouling and / or corrosion in distillation equipment can be suppressed while suppressing adverse effects such as the deposition of inorganic salts and the occurrence of corrosion in downstream equipment.

[0016] In one aspect, the present disclosure provides a method for reducing the cost of treatment for suppressing fouling and corrosion and increasing the yield of valuable products while reducing equipment troubles by monitoring operating conditions that vary according to the demand for petroleum products, component concentrations in the apparatus, etc., predicting the deposition locations of ammonium salts and the like that can cause fouling and corrosion, and controlling the supply location and supply amount of chemicals according to the prediction. According to the present disclosure, in one or more embodiments, a chemical supply method capable of preventing the occurrence of fouling / corrosion and operating a petroleum refining process while reducing the treatment cost related to suppressing the occurrence of fouling / corrosion can be provided. Also, according to the present disclosure, in one or more embodiments, there may be an effect that the differential pressure (pressure loss) generated during operation by salts such as ammonium chloride can be eliminated.

[0017] By using an oil-soluble surfactant having a nitrogen-containing hydrophilic group as the supplied chemical, the mechanism by which the deposition and corrosion of dirt in the distillation equipment can be suppressed while suppressing adverse effects such as the occurrence of corrosion in the subsequent equipment is presumed as follows. In the prior art, ammonium chloride is reacted with choline to form choline chloride, and dirt in the distillation equipment is suppressed. Choline chloride has lower corrosivity than ammonium chloride and can suppress the increase in differential pressure. However, there is a problem that it cannot suppress corrosion because it does not have an anticorrosive action. On the other hand, in the case of the oil-soluble surfactant having a nitrogen-containing hydrophilic group used in the present disclosure, the ammonium salt is discharged out of the system in a state of being dispersed in the process fluid. Therefore, not only can the dirt (deposition of dirt) at the target location be prevented, but also since it has an effect as an anticorrosive film, it can exhibit the effect of suppressing corrosion to the subsequent equipment. Furthermore, the oil-soluble surfactant having a nitrogen-containing hydrophilic group can adsorb to the ammonium salt and disperse the ammonium salt even in a state where the ammonium salt is aggregated, and thereby can further suppress the deposition of dirt caused by the ammonium salt. However, the present disclosure may not be construed as being limited to these mechanisms.

[0018] In the present disclosure, the "petroleum refining process" refers to all or part of the processes from hydrocarbons such as crude oil as raw materials until various petroleum products are produced from them. The petroleum refining process may include, in one or more embodiments, heating hydrocarbons such as crude oil, and separating the heated hydrocarbons into various components such as volatile oils such as LPG and naphtha, and gas oil using the difference in boiling points in an atmospheric distillation unit.

[0019] In the present disclosure, the "distillation equipment in the petroleum refining process" includes, in one or more embodiments, an atmospheric distillation column, a vacuum distillation column, FCC, a residue fluid catalytic cracking unit, a catalytic reforming unit, a pyrolysis unit, a hydrodesulfurization unit, a hydrocracking unit, and their auxiliary equipment, etc. The auxiliary equipment includes, in one or more embodiments, an air fin cooler, a condenser, an accumulator, a reflux, and a side stripper, etc., as well as the piping and pumps associated therewith.

[0020] Figures 1 and 2 respectively show an example of the flow of distillation equipment equipped with an atmospheric distillation column and FCC. Figure 1 is an example of the flow of distillation equipment equipped with an atmospheric distillation column 2. In this distillation equipment, the crude oil heated in the heating furnace 1 is introduced into the atmospheric distillation column 2. The atmospheric distillation column 2 has three reflux series, namely the side reflux (Top Pump Around) 3, the side reflux (Middle Pump Around) 4, and the side reflux (Bottom Pump Around) 5 in order from the top of the column, and side strippers 6, 7, and 8 provided near the side of the column. The side refluxes 3, 4, and 5 consist of a pump (not shown) and a cooler. Stripping steam (Steam in the figure) is supplied to the side strippers 6, 7, and 8 respectively. A naphtha fraction is withdrawn from the top of the column, a kerosene fraction is withdrawn from the side stripper 6, a light gas oil fraction is withdrawn from the side stripper 7, a heavy gas oil fraction is withdrawn from the side stripper 8, and a heavy oil fraction (residual oil) is withdrawn from the bottom of the column. The top fraction of the column is cooled by an air fin cooler (air-cooled cooler) 9 and a condenser (water-cooled cooler) 10 and introduced into the accumulator 11. The top fraction of the column introduced into the accumulator 11 is separated into a naphtha fraction, condensed water (drain water), and a gas fraction (off-gas). A part of the naphtha fraction is refluxed to the top of the atmospheric distillation column 2 as the top reflux through the top reflux line 12. The top of the atmospheric distillation column 2 is usually at 90°C to 160°C and 60 kPa to 140 kPa.

[0021] In a distillation facility equipped with an atmospheric distillation column 2, facilities where fouling or corrosion caused by ammonium salts or amine salts may occur include, in one or more embodiments, inside the distillation column 2 (particularly near the top of the column), side reflux 3, the overhead piping connecting the distillation column 2 and the air fin cooler 9, the air fin cooler 9, and the condenser 10, etc.

[0022] Figure 2 is an example of the flow of FCC. FCC is a device that decomposes heavy oil fractions, which are high-boiling components with large molecular weights, into hydrocarbons, and converts them into components such as propylene, propane, butane, gasoline, kerosene, and gas oil. FCC includes a regeneration column 21, a reaction column 22, and a distillation column 23. The heavy oil fraction (Feed in the figure), which is the raw material, is mixed with the high-temperature catalyst circulated from the regeneration column 21 together with steam (Steam in the figure). When the heavy oil fraction and the catalyst come into contact at a high temperature for a short time, a decomposition reaction occurs, and the heavy oil fraction is introduced into the reaction column 22 in a state where the decomposition reaction is taking place, and there it is separated into the catalyst and hydrocarbon vapor. The separated catalyst is transferred to the regeneration column 21 and regenerated there by combustion removal. On the other hand, the hydrocarbon vapor is introduced into the distillation column 23. The distillation column 23 has three side refluxes: side reflux (Top Pump Around) 24A, side reflux (Middle Pump Around) 24B, and side reflux (Bottom Pump Around) 24C, and side strippers (LCO stripper) 33 and side stripper (HCO stripper) 34. The introduced hydrocarbon vapor is separated by distillation in the distillation column 23, and a naphtha fraction is withdrawn from the top of the column, a light gas oil fraction is withdrawn from the side stripper 33, a heavy gas oil fraction is withdrawn from the side stripper 34, and a heavy oil fraction is withdrawn from the bottom of the column. The top fraction is cooled by an air fin cooler (air-cooled cooler) 25 and a condenser (water-cooled cooler) 26 and led to an accumulator 27. In the accumulator 27, the top fraction is separated into condensed water (drain water), gas fraction, and the remaining fraction (naphtha fraction). A part of the remaining fraction is refluxed as top reflux to the uppermost stage of the distillation column 23 through a pump via a top reflux line 35. The top of the distillation column 23 is usually at 100°C to 150°C and 100 kPa to 200 kPa. The gas fraction separated in the accumulator 27 is introduced into a high-pressure separator 30 through a compressor 28 and a cooler 29, where it is separated into condensed water (drain water), light gas fraction, and other gas fractions. The light gas fraction is introduced into an absorber 31, and the LPG fraction is recovered. The other gas fractions are introduced into a stripper 32 and then distilled and separated into fractions such as gasoline fraction, butane, propane, and propylene.

[0023] In the FCC flow shown in FIG. 2, equipment where fouling or corrosion due to ammonium salts or amine salts may occur includes, in one or more embodiments, inside the distillation column 23, the top piping connecting the distillation column 23 and the air fin cooler 25, the air fin cooler 25, the condenser 26, the side reflux 24A, and the compressor 28, etc.

[0024] [Supply method of the present disclosure] The supply method of the surfactant of the present disclosure relates to a supply method of a surfactant for suppressing or preventing fouling or corrosion in a distillation facility, and includes monitoring the operation of the distillation facility and controlling the supply rate of the surfactant according to at least one deposition location of ammonium salts and amine salts in the distillation facility predicted based on the monitoring.

[0025] As used herein, "operation monitoring" refers to measuring predetermined monitoring items (parameters), calculating calculated values from the measured values as necessary, and recording the obtained measured values and calculated values. Monitoring aims to obtain predicted values for the purpose by calculating measured values or input values of parameters related to the monitoring items using a program set in the monitoring device. The operation monitoring can be performed using a program applied at an oil refinery provided by Nalco in one or more embodiments.

[0026] As monitoring items, in one or more embodiments, temperature, pressure, naphtha flow rate, naphtha specific gravity, naphtha distillation characteristics, drain water volume, drain water chloride ion concentration, drain water ammonium ion concentration, and drain water pH in the distillation column, etc. may be mentioned. Any parameters related to these monitoring items may be measured and recorded. By monitoring these items, the tendency of the environment in the target distillation facility (for example, substances that can cause dirt such as ammonium salts or are likely to precipitate substances that can cause corrosion) can be grasped, and as a result, the precipitation location can be accurately predicted. Also, the effect of chemical agent supply, that is, the dispersion tendency of substances that can cause dirt such as ammonium salts or corrosion can be grasped. As drain water, in one or more embodiments, drain water discharged from an accumulator, a separator, a side reflux, etc. may be mentioned. In one or more embodiments, instead of or in addition to the drain water chloride ion concentration, the chloride ions in the top pump around may be monitored.

[0027] Monitoring may be automatic, semi-manual, or manual in one or more embodiments. Also, some items may be performed automatically, semi-manually, or manually. The measurement of the monitoring items can be performed using known data collection devices or methods suitable for each item in one or more embodiments.

[0028] In the present disclosure, the "ammonium salts and amine salts" include, in one or more embodiments, hydrochlorides such as ammonium chloride, ammonium hydrosulfide, ammonium sulfate, monoethanolamine, methoxypropylamine, dimethylethanolamine, and methoxyisopropylamine.

[0029] In one or more embodiments, the control of the supply rate of the surfactant may include determining the supply location and appropriate supply amount of the surfactant according to the predicted precipitation location based on monitoring, and supplying the surfactant accordingly. In one or more embodiments, the appropriate amount includes an amount sufficient to disperse the ammonium salts and amine salts and suppress their precipitation.

[0030] In the present disclosure, the prediction of the precipitation location based on monitoring can be performed in one or more embodiments based on the descriptions of the embodiments and / or examples described below. Also, in one or more embodiments, the prediction of the precipitation location based on monitoring may be performed using the information provided by the monitoring system and / or the above-described program (for example, the top temperature of the tower, the salt precipitation temperature, etc.).

[0031] In one or more embodiments, the control of the supply rate of the surfactant includes increasing the supply rate of the surfactant at a location where the precipitation of the ammonium salt is predicted to increase or tend to increase, while decreasing the supply rate of the surfactant at a location where the precipitation of the ammonium salt is predicted to decrease or tend to decrease. Also, in one or more embodiments, the control of the supply rate includes maintaining the supply rate of the surfactant at a location where it is determined that the precipitation of the ammonium salt is moderately suppressed or prevented. In one or more embodiments that are not particularly limited, when it is predicted that the deposition location of at least one of the ammonium salt and the amine salt will be inside the distillation column, the control of the supply rate includes increasing the supply rate of the surfactant supplied to the top of the distillation column. In one or more embodiments, the "surfactant supplied to the top of the distillation column" in this aspect includes the top of the distillation column, the vicinity of the top, and the near vicinity of the top. In one or more embodiments, supplying to the top includes supplying to the pipe supplied to the top, the vicinity of the top, or the near vicinity of the top. In one or more embodiments, examples of the pipe include the top reflux line and the side pump around line, etc., and preferably it is a line that returns to the uppermost stage of the distillation column. In one or more embodiments that are not particularly limited, when it is predicted that the deposition location of at least one of the ammonium salt and the amine salt will be inside the distillation column, the control of the supply rate includes increasing the supply amount of the surfactant to the top reflux line and the top pump around line (extraction part and / or return part).

[0032] In one or more embodiments of the supply method of the present disclosure, the location where the surfactant is supplied may be one location, or may be two or more locations. Preferably it is two or more locations. Further, in one or more embodiments, the supply method of the present disclosure may include supplying to two or more locations within one distillation facility. The "one distillation facility" in the present disclosure refers to, in one or more embodiments, a facility including an atmospheric distillation column, a vacuum distillation column, FCC, a residue fluid catalytic cracking unit, a catalytic reforming unit, a pyrolysis unit, a hydrodesulfurization unit, a hydrocracking unit, etc., and the facilities attached to each of them. In the case of an atmospheric distillation column, in one or more embodiments, the atmospheric distillation column, the side reflux and side stripper provided in the atmospheric distillation column, the air fin cooler, the condenser, the accumulator, and the top reflux line, and the pipes and pumps connecting each of them are collectively referred to as one distillation facility. In the case of FCC, in one or more embodiments, a regeneration column, a reaction column, a distillation column, a side reflux and a side stripper provided in the distillation column, an air fin cooler, a condenser, an accumulator and a top reflux line, and the pipes and pumps connecting them are collectively referred to as one distillation facility.

[0033] When the surfactant is supplied to two or more locations within one distillation facility, the supply method of the present disclosure includes, in one or more embodiments, controlling the supply rate of the surfactant so as to balance the supply amounts among a plurality of surfactant supply locations within one distillation facility.

[0034] Taking as an example the case where, in one or more embodiments, the surfactant is supplied to two locations in one distillation facility. When it is predicted that at least one deposition location of the ammonium salt and the amine salt is inside the distillation column, the deposition of dirt in the distillation column can be suppressed by dispersing the salt by increasing the addition of the surfactant in the process fluid supplied near the top of the distillation column (for example, the process fluid in the reflux line). On the other hand, in the process fluid supplied after the top pipe, the corrosion of the facility can be suppressed by obtaining the film effect of the surfactant by decreasing or maintaining the supply rate of the surfactant. Similarly, when it is predicted that at least one deposition location of the ammonium salt and the amine salt is after the top pipe, the deposition of dirt can be suppressed by dispersing the salt by increasing the addition of the surfactant in the process fluid supplied after the top pipe (for example, the process fluid in the top pipe). On the other hand, in the process fluid supplied inside the distillation column, the corrosion of the facility can be suppressed by obtaining the film effect of the surfactant by decreasing or maintaining the supply rate of the surfactant. When the supply control of the above-mentioned agent (surfactant) according to the present disclosure is not performed and the supply rate of the surfactant is increased compared to the supply rate of the surfactant necessary to suppress or prevent precipitation of ammonium salts or the like, it may cause water brought into the subsequent stage to cause corrosion of the equipment due to the influence on oil-water separation. Furthermore, when the surfactant is supplied in excess for a long period of time, the surfactant itself may cause dirt. Note that the above embodiment is merely an explanation of one embodiment of the present disclosure and does not limit the present disclosure.

[0035] In one or more embodiments, the control of the supply rate of the surfactant may include determining whether the supply location and supply rate of the surfactant during monitoring are producing appropriate results, and if not, changing at least one of the supply location and supply rate of the surfactant. Appropriate results include, in one or more embodiments, that a sufficient amount of surfactant is supplied for the dispersion of ammonium salts or amine salts, and that no more than the necessary amount is supplied. The determination can be made based on the monitoring results in one or more embodiments.

[0036] The surfactant used in the supply method of the present disclosure is an oil-soluble surfactant having a nitrogen-containing hydrophilic group. In one or more embodiments, the surfactant of the present disclosure can function as a corrosion inhibitor or a film-forming agent for suppressing or preventing dirt or corrosion in distillation equipment. Therefore, as the surfactant of the present disclosure, in one or more embodiments, an oil-soluble surfactant having a nitrogen-containing hydrophilic group that has been used or can be used in the future to suppress or prevent the deposition of dirt or corrosion in distillation equipment can be used. The "oil-soluble surfactant" in the present disclosure refers to a surfactant having a higher solubility in an organic solvent than in water. The oil-soluble surfactant refers to one having an HLB of 10, 9, or 8 or less. In one or more embodiments, the "HLB (hydrophilic lipophilic balance)" in the present disclosure can be calculated using the following Griffin formula. HLB = 20 × (sum of formula weights of hydrophilic moieties / molecular weight)

[0037] Examples of the "oil-soluble surfactant having a nitrogen-containing hydrophilic group" in the present disclosure include amidoamine-type oil-soluble surfactants. Examples of the oil-soluble surfactant having a nitrogen-containing hydrophilic group include, in one or more embodiments, reaction products of polyamines and fatty acids, and particularly, reaction products of polyamines and tall oil fatty acids are preferred.

[0038] Examples of the polyamine include, in one or more embodiments, polyamines represented by the following formula. [Chemical formula] In the above formula, R 1 is a linear or branched alkylene group having 1 to 10 carbon atoms, R 2 is a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms which may be substituted with one or more amino groups, and x is an integer of 1 to 10. Examples of the polyamine represented by the above formula include, in one or more embodiments, trimethylamine, triethanolamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, and polyethyleneimine. Examples of the fatty acid include, in one or more embodiments, unsaturated fatty acids. Examples of the unsaturated fatty acid include, in one or more embodiments, tall oil (tall oil fatty acid, or TOFA), coconut oil, canola oil, and palm kernel oil.

[0039] Examples of the oil-soluble surfactant having a nitrogen-containing hydrophilic group used in the method of the present disclosure include, in one or more embodiments, reaction products of tetraethylenepentamine and tall oil fatty acids, reaction products of diethylenetriamine and tall oil fatty acids, and imidazoline derivatives obtained by cyclizing them. Examples of the agent containing an oil-soluble surfactant having a nitrogen-containing hydrophilic group include, in one or more embodiments, a mixture of amides and imidazolines, or a mixture of amides and esters.

[0040] In one or more embodiments, the supply method of the present disclosure may include predicting a deposition location of at least one of an ammonium salt and an amine salt in a distillation facility based on operation monitoring of the distillation facility.

[0041] [Method for Suppressing Deposition of Contamination of the Present Disclosure] A method for suppressing deposition of contamination caused by inorganic salts contained in crude oil in a distillation facility of a petroleum refining process, the method including monitoring the operation of the distillation facility and controlling a supply rate of a surfactant according to a deposition location of at least one of an ammonium salt and an amine salt in the distillation facility predicted based on the monitoring. The surfactant used in the method for suppressing deposition of contamination of the present disclosure is an oil-soluble surfactant having a nitrogen-containing hydrophilic group, and the same surfactant as the supply method of the present disclosure can be used. Regarding the monitoring and control based on prediction of the deposition location in the method for suppressing deposition of contamination of the present disclosure, it can be performed in the same manner as the supply method of the present disclosure.

[0042] In one or more embodiments, the "inorganic salts contained in crude oil" in the present disclosure include ammonium salts, amine salts, sodium salts, calcium salts, magnesium salts, and the like. The method of the present disclosure is preferably used for suppressing deposition of contamination caused by ammonium salts and / or amine salts in one or more embodiments. The "suppression of deposition of contamination" in the present disclosure may include, in one or more embodiments, dispersion of inorganic salts, suppression of precipitation or aggregation of inorganic salts, dispersion of aggregated inorganic salts, suppression or prevention of adhesion of contamination caused by inorganic salts, and removal of the adhered contamination.

[0043] [Method for Suppressing Corrosion of the Present Disclosure] In other aspects, the present disclosure relates to a method for suppressing corrosion of distillation equipment in an oil refining process, which includes monitoring the operation of the distillation equipment and controlling the supply rate of a surfactant according to at least one deposition location of ammonium salt and amine salt in the distillation equipment predicted based on the monitoring. The surfactant used in the corrosion suppression method of the present disclosure is an oil-soluble surfactant having a nitrogen-containing hydrophilic group, and a surfactant similar to the supply method of the present disclosure can be used. Regarding the monitoring in the corrosion suppression method of the present disclosure and the control based on the prediction of the deposition location, it can be carried out in the same manner as the supply method of the present disclosure.

[0044] [Automatic Chemical Supply System of the Present Disclosure] In other aspects, the present disclosure relates to an automatic chemical supply system for suppressing the deposition of dirt caused by inorganic salts contained in crude oil in distillation equipment in an oil refining process, which includes a supply line for supplying the chemical to the distillation equipment, a monitoring unit for monitoring the operation of the distillation equipment, and a control unit for controlling the supply rate of the chemical through the supply line. The control unit is configured to measure and / or predict at least one deposition location of ammonium salt and amine salt based on the monitoring result in the monitoring unit and control the supply of the chemical through the supply line accordingly.

[0045] In one or more embodiments, the monitoring unit includes an analyzer for monitoring the operation. In one or more embodiments, the monitoring unit and the analyzer are connected by a wired network such as a cable, or the Internet, a wireless interface, and a Bluetooth (registered trademark) wireless network, etc., through which data transmission is possible. In one or more embodiments, the analyzer may include a device capable of outputting the monitoring result online.

[0046] In one or more embodiments, the control unit receives and processes information such as monitoring results obtained by the monitoring unit, predicts the deposition locations of at least one of ammonium salts and amine salts, determines the supply location and / or supply amount of the chemical agent based on the prediction, and includes a control device capable of performing a series of operations of instructing the control of the supply amount of the chemical agent in the supply line. In one or more embodiments, the control device includes a manual operator, a processor, a storage device, a digital storage medium, various monitors such as a display and a touch screen, and other electronic devices. In one or more embodiments, the control device includes a program capable of performing the above prediction and determination of the supply amount, and algorithms and the like.

[0047] In one or more embodiments, the control unit may include a recording unit that records monitoring results, prediction results (such as deposition locations), supply locations and supply amounts determined based on the prediction, and the like. In one or more embodiments, the control unit is connected via the Internet so as to be able to exchange data with a cloud server arranged on the Internet, and may record the above data such as monitoring results in the cloud server.

[0048] In one or more embodiments, in the control unit, a monitoring schedule may be set in advance. The control unit instructs the monitoring unit to perform monitoring according to the set schedule, and the monitoring unit performs monitoring according to the instruction.

[0049] In one or more embodiments, the system of the present disclosure can also be used as a system for automatically supplying a chemical agent for suppressing corrosion in a distillation facility in an oil refining process. In one or more embodiments, the system of the present disclosure can be used in the supply method, the method for suppressing the deposition of dirt, and the method for suppressing corrosion of the present disclosure.

[0050] In one or more embodiments, the method and system of the present disclosure can also be used for supplying neutralizing agents, corrosion inhibitors, and inhibitors used for preventing dirt and corrosion in petroleum refining processes other than the above surfactants.

[0051] Hereinafter, an embodiment of the present disclosure will be described in detail while exemplifying it. Needless to say, the present disclosure is not limited to the following embodiments.

[0052] (Embodiment 1) In Embodiment 1 of the present disclosure, the chemical supply method in the FCC flow shown in FIG. 2 will be described as an example. The raw material supplied to FCC is one of the facilities that contains a large amount of nitrogen derived from organic substances and generates a large amount of ammonium salts or amine salts.

[0053] Embodiment 1 regards an FCC including a regeneration tower 21 and a reaction tower 22, and a subsequent distillation tower 23 and its attached equipment as one distillation facility, predicts the precipitation location of ammonium chloride salt, and is an example of a case where supply control of a surfactant having a nitrogen-containing hydrophilic group is performed as a chemical for preventing dirt. The attached equipment in Embodiment 1 includes three side refluxes 24A, 24B, and 24C provided in the distillation tower 23 and side strippers 33, 34, an air fin cooler 25, a condenser 26, and an accumulator 27 connected to the top pipe of the distillation tower 23, pipes and pumps connecting them, and a top reflux line 35.

[0054] In the first embodiment, the supply locations of the chemical agent (surfactant) are the top reflux line 35 (between the accumulator 27 and near the top of the distillation column 23: arrow X), the top pipe (the pipe between the distillation column 23 and the air fin cooler 25: arrow Y), and the extraction section of the side reflux (Top Pump Around) 24A (arrow Z). The supply of the chemical agent may be at two locations, the top reflux line 35 (arrow X) and the top pipe (arrow Y), or may be at all three locations, the top reflux line 35 (arrow X), the top pipe (arrow Y), and the extraction section of the side reflux 24A (arrow Z). When the line returning to the uppermost stage of the distillation column 23 is the side reflux 24A, in one or more embodiments, the supply location of the chemical agent may be the return line of the side reflux 24A instead of the extraction section of the side reflux 24A (arrow Z).

[0055] The top temperature of the distillation column 23 is higher than the precipitation temperature of ammonium chloride under normal operating conditions. Therefore, under normal operating conditions, ammonium chloride rarely precipitates inside the distillation column 23, and precipitation in the air fin cooler 25, condenser 26, accumulator 27, etc. downstream of the top piping of the distillation column 23 has been a problem. On the other hand, when increasing the production amount of fractions with a high boiling point range such as light gas oil fractions and heavy gas oil fractions other than gasoline, the operation is carried out with the top temperature of the distillation column 23 lowered below normal. As a result, the occurrence of fouling and corrosion caused by ammonium chloride at locations different from those conventionally assumed has been confirmed. The inventors of the present invention have found that by measuring the above various monitoring items, the precipitation temperature of ammonium chloride is constantly fluctuating, and due to the change in the above operating conditions, the precipitation temperature of ammonium chloride becomes equal to or higher than the top temperature of the distillation column 23, resulting in the fluctuation of the precipitation location of ammonium chloride. That is, in one non-limiting form, when the top temperature of the distillation column 23 is lower than the precipitation temperature of ammonium chloride, the precipitation location of ammonium chloride is inside the distillation column 23, and the precipitation amount of ammonium chloride inside the distillation column 23 increases. On the other hand, when the top temperature of the distillation column 23 is higher than the precipitation temperature of ammonium chloride, the precipitation location of ammonium chloride is downstream of the top piping, and there is a tendency that the precipitation amount of ammonium chloride downstream of the top piping of the distillation column 23 may increase.

[0056] Monitoring is performed, for example, on the temperature, pressure, naphtha flow rate, naphtha specific gravity, naphtha distillation characteristics, drain water volume, drain water chloride ion concentration, drain water ammonium ion concentration, and drain water pH in the distillation column. As the drain water, the drain water of the accumulator 27 can be mentioned. The measurement of various monitoring items can be carried out, for example, by using the sampling methods and parameter measurement methods disclosed in US4,335,072 (top corrosion simulator), US5,425,267 (corrosion simulator and method for simulating the corrosion activity of a process stream), US5,326,482 (online acid monitoring and neutralizer supply control of overhead water in an oil refinery), US5,324,665 (online method for monitoring chloride levels in a fluid stream), US5,302,253 (online acid monitoring and neutralizer supply control of overhead water in an oil refinery), US9,834,732 / JP6,454,641 (development design and implementation of a control system and algorithm based on an analyzer), and US10,316,261 / JP5,771,527 (method for reducing corrosion and deposition of corrosion by-products in a crude oil unit). The contents of these documents are incorporated herein by reference as part of the present disclosure.

[0057] Based on the monitoring, the precipitation temperature of ammonium chloride is predicted / calculated, and the precipitation location of ammonium chloride is predicted. As an example of the monitoring items used for the prediction, the chloride ion concentration and ammonium ion concentration of the drain water of the accumulator 27, the temperature in the distillation column including the top temperature, and the naphtha distillation characteristics, etc. can be mentioned.

[0058] The prediction of the deposition location of ammonium chloride can be carried out, for example, based on the top temperature of the distillation column 23 and the ammonium chloride deposition temperature (predicted value). When the top temperature of the distillation column 23 is higher than the ammonium chloride deposition temperature, it can be predicted that the top piping of the distillation column 23 and the downstream air fin cooler 25, condenser 26, compressor 28, etc. will be the deposition locations. When the top temperature of the distillation column 23 is lower than or equivalent to the ammonium chloride deposition temperature, it can be predicted that the inside of the top of the distillation column 23 and the reflux facilities such as the side reflux 24A will be the deposition locations.

[0059] In one non-limiting aspect, together with the prediction of the deposition location, the prediction of the deposition amount of ammonium chloride at the deposition location may or may not be performed. For the prediction of the deposition amount of ammonium chloride, for example, when the top temperature of the distillation column 23 is higher than the ammonium chloride deposition temperature, it can be predicted that the deposition amounts of the top piping of the distillation column 23 and the downstream air fin cooler 25, condenser 26, compressor 28, etc. will increase, and the deposition amounts of the inside of the top of the distillation column 23 and the reflux facilities such as the side reflux 24A will decrease. On the other hand, when the top temperature of the distillation column 23 is lower than or equivalent to the ammonium chloride deposition temperature, it can be predicted that the deposition amounts of the top piping of the distillation column 23 and the downstream air fin cooler 25, condenser 26, compressor 28, etc. will decrease, and the deposition amounts of the inside of the top of the distillation column 23 and the reflux facilities such as the side reflux 24A will increase.

[0060] The prediction of the deposition location and the deposition amount may further be carried out in consideration of the amount of ammonium chloride in a dispersed state based on the supply amount of the chemical agent containing the surfactant already supplied as necessary.

[0061] According to the prediction of the precipitation location and precipitation amount, determine the supply location and supply amount of the surfactant, and supply the surfactant. For example, when it is predicted that the precipitation amount increases in the top pipe of the distillation column 23 and the downstream air fin cooler 25, condenser 26, compressor 28, etc., and the precipitation amount decreases in the top of the distillation column 23 and the reflux equipment such as the side reflux 24A, etc., increase the supply amount at the supply location indicated by arrow Y, and decrease the supply amount at the supply locations indicated by arrow X, or arrow X and Z, etc. It is preferable to control the supply of the surfactant so as to balance the supply amounts among a plurality of supply locations in one distillation facility. On the other hand, when it is predicted that the precipitation amount decreases in the top pipe of the distillation column 23 and the downstream air fin cooler 25, condenser 26, compressor 28, etc., and the precipitation amount increases in the top of the distillation column 23 and the reflux equipment such as the side reflux 24A, etc., increase the supply amount at the supply locations indicated by arrow X or arrow X and Z, and decrease the supply amount at the supply location indicated by arrow Y, etc. It is preferable to control the supply of the surfactant so as to balance the supply amounts among a plurality of supply locations in one distillation facility. The control of the supply rate of the surfactant may be performed, for example, using the methods disclosed in US Pat. No. 5,066,199 (Method for injecting a processing chemical using a constant flow positive displacement pumping device) and US Pat. No. 5,195,879 (Improved method for injecting a processing chemical using a constant flow positive displacement pumping device). The contents of these documents are incorporated herein by reference as part of the present disclosure.

[0062] In the first embodiment, the case where ammonium chloride salt is used as the ammonium salt / amine salt for predicting the precipitation location is taken as an example for explanation, but the present disclosure is not limited thereto.

[0063] (Embodiment 2) In the second embodiment of the present disclosure, the chemical supply method in a distillation facility equipped with the atmospheric distillation column shown in FIG. 1 will be described by taking it as an example.

[0064] Embodiment 2 is an example in which the atmospheric distillation column 2 and its auxiliary equipment are regarded as one distillation facility, the precipitation location of ammonium chloride salt is predicted, and the supply control of a surfactant having a nitrogen-containing hydrophilic group is performed as a fouling prevention agent. As the auxiliary equipment in Embodiment 1, there are three side refluxes 3, 4, and 5 provided in the atmospheric distillation column 2, side strippers 6, 7, and 8, an air fin cooler 9 connected to the top pipe of the distillation column 2, a condenser 10, and an accumulator 11, pipes and pumps connecting them, and a top reflux line 12 connecting the accumulator 11 and the atmospheric distillation column 2.

[0065] The supply locations of the agent in Embodiment 2 are three locations: the top reflux line 12 (between the accumulator 11 and the vicinity of the top of the distillation column 2: arrow A), the top pipe (the pipe between the distillation column 2 and the air fin cooler 9: arrow B), and the extraction section of the side reflux (Top Pump Around) 3 (arrow C). In one or more embodiments, the supply location of the agent may be the return line section of the side reflux 3.

[0066] Monitoring, prediction of the precipitation location based on the monitoring, and supply control of the surfactant can be performed in the same manner as in Embodiment 1.

[0067] The present disclosure further relates to one or more of the following embodiments. [1] A method for supplying a surfactant to a distillation facility in a petroleum refining process, comprising: monitoring the operation of the distillation facility, and controlling the supply rate of the surfactant according to the precipitation location of at least one of ammonium salt and amine salt in the distillation facility predicted based on the monitoring, wherein the surfactant is an oil-soluble surfactant having a nitrogen-containing hydrophilic group. [2] The method according to [1], wherein the control of the supply rate includes increasing the supply rate of the surfactant supplied to the top of the distillation column when it is predicted that the precipitation location of at least one of the ammonium salt and the amine salt is in the distillation column. [3] The monitoring according to [1] or [2] includes measuring at least one selected from the group consisting of temperature, pressure, naphtha flow rate, naphtha specific gravity, naphtha distillation characteristics, drain water amount, drain water chloride ion concentration, drain water ammonium ion concentration, and drain water pH in the distillation column. [4] including supplying the surfactant to two or more locations within one distillation facility, The control according to any one of [1] to [3] includes controlling the supply rate of the surfactant so as to balance the supply amounts among a plurality of supply locations within the one distillation facility. [5] A method for suppressing the deposition of dirt caused by inorganic salts contained in crude oil in a distillation facility of a petroleum refining process, monitoring the operation of the distillation facility, and controlling the supply rate of the surfactant according to the predicted precipitation location of at least one of the ammonium salt and the amine salt in the distillation facility based on the monitoring, wherein the surfactant is an oil-soluble surfactant having a nitrogen-containing hydrophilic group. [6] A method for suppressing corrosion of a distillation facility in a petroleum refining process, monitoring the operation of the distillation facility, and controlling the supply rate of the surfactant according to the predicted precipitation location of at least one of the ammonium salt and the amine salt in the distillation facility based on the monitoring, wherein the surfactant is an oil-soluble surfactant having a nitrogen-containing hydrophilic group. [7] An automatic supply system for a chemical agent for suppressing the deposition of dirt caused by inorganic salts contained in crude oil in a distillation facility in a petroleum refining process, a supply line for supplying the chemical agent to the distillation facility and A monitoring unit that monitors the operation of the distillation equipment, and a control unit that controls the supply rate of the chemical agent through the supply line. The system is provided with these components. Based on the monitoring results in the monitoring unit, the control unit predicts at least one precipitation location of ammonium salt and amine salt, and is configured to control the supply of the chemical agent through the supply line accordingly. [8] The system according to [7] for performing the method according to any one of [1] to [6].

[0068] Hereinafter, the present disclosure will be described in more detail with reference to examples. However, these are illustrative and the present disclosure is not limited to these examples.

Examples

[0069] [Salt dispersion test] First, 10 ml of top tower accumulator naphtha (hereinafter referred to as naphtha) and 0.25 ml of ammonium chloride pure water solution or 0.25 ml of methanol were mixed. The appearance of these mixed solutions was observed. As a result, no precipitation was confirmed in any of the mixed solutions.

[0070] Next, the confirmation of ammonium chloride dispersion by a surfactant was performed according to the following procedure. 1. 1 g of ammonium chloride was dissolved in 50 ml of methanol to prepare a solution. 2. As a comparative experimental example, 15 ml of naphtha and the solution prepared in 1. were mixed, and the appearance was observed. The appearance was evaluated according to the following appearance observation evaluation criteria. The results are shown in Figure 3A. 3. As an experimental example, 100 ppm of any one of the following three types of surfactants was added to naphtha, and then the solution prepared in 1. was added and mixed, and the appearance was observed. The appearance was evaluated according to the following appearance observation evaluation criteria. The results are shown in Figure 3A. 4. The absorbance results measured at 660 nm are shown in the graphs of Figure 3A and Figure 3B. [Surfactant] · Experimental Example 1: The reaction product of triethylamine and tall oil fatty acid · Experimental Example 2: Reactant of diethylenetriamine and tall oil fatty acid · Experimental Example 3: Imidazoline derivative obtained by cyclizing the reactant of polyamine and tall oil fatty acid [Appearance Observation Evaluation Criteria] A: The supernatant is turbid and the dispersion effect is good. No precipitation of particles is observed at the bottom. B: The supernatant is turbid and the dispersion effect is good, but slight precipitation of small particles is observed at the bottom. C: The supernatant is slightly turbid and the dispersion effect can be confirmed, but since large particle precipitation is observed at the bottom, the dispersion effect is insufficient.

[0071] As a result, as shown in FIGS. 3A and 3B, the dispersion effect of ammonium chloride by the above surfactant was confirmed.

[0072] (Example 1) Monitoring the operation in the FCC distillation equipment in the petroleum refining process shown in FIG. 2, predicting the precipitation temperature of ammonium chloride based on the monitoring, predicting the precipitation location of ammonium chloride in the distillation column 23 and its auxiliary equipment, and controlling the supply rate of the chemical at the chemical supply locations (arrows Y and Z in FIG. 2). In this equipment, the line returning to the uppermost stage of the distillation column 23 was the side reflux (top pump around) 24A. Also, during the test period, the injection of the chemical for film purpose was continuously performed into the top pump around 24A. It has been confirmed that the withdrawal temperature of the top pump around 24A is higher than the salt precipitation temperature. [Monitoring Items] · Top temperature of distillation column 23 · Chloride ion concentration of the drain water of accumulator 27 · Chloride ion concentration of the top pump around 24A · Ammonium chloride precipitation temperature predicted using a commercially available program (manufactured by Nalco) based on the temperature, pressure, naphtha flow rate, naphtha specific gravity, naphtha distillation characteristics, drain water volume, drain water chloride ion concentration, drain water ammonium ion concentration, and drain water pH in the distillation column [Chemicals Used] · Reaction product of polyamine and tall oil fatty acid (an oil-soluble surfactant having a nitrogen-containing hydrophilic group, a film-forming chemical for distillation equipment manufactured by Nalco) [Chemical supply location] · Pipe between the top of the 23rd distillation column and the air fin cooler 25 (arrow Y in Figure 2) · Extraction part of the top pump around 24A (arrow Z in Figure 2)

[0073] The results are shown in Table 1 and Figure 4 below. Figure 4 is a graph showing the chloride ion concentration of the drain water (top drain water) of the accumulator 27 and the chloride ion concentration of the top pump around 24A during periods 1 to 3.

Table 1

[0074] As shown in the above table, under the operating conditions of period 1, the predicted salt precipitation temperature of ammonium chloride was lower than the top temperature, and based on this, the precipitation location of the ammonium salt was predicted to be after the top pipe. Therefore, control was carried out to increase the chemical supply rate of the top pipe (arrow Y) more than that of the top pump around 24A (arrow Z). As a result, as shown in the above table and Figure 4, a monitoring result was obtained that the chloride ion concentration of the accumulator 27 was higher than that of the top pump around 24A. That is, it was confirmed that good salt dispersion was achieved in the top pipe and the deposition of dirt was suppressed by the above prediction and chemical supply control. Under the operating conditions of Period 2, the predicted salt precipitation temperature of ammonium chloride was higher than the top tower temperature, and based on this, the precipitation location of the ammonium salt was predicted to be inside the distillation column 23. However, in Period 2, the control of chemical agent supply was not carried out. As a result, as shown in the above table and Figure 4, from the monitoring results of the chloride ion concentration of the accumulator 27 and the chloride ion concentration of the top pump-around 24A, a slight decrease in the chloride ion concentration of the accumulator 27 and an increase in the chloride ion concentration of the top pump-around 24A were confirmed. However, since it was lower than the predicted amount of ammonium chloride, it was suggested that the salt dispersion was insufficient and there was a possibility that dirt was deposited inside the distillation column 23. In Period 3, the operation was carried out under the same operating conditions as those in Period 2 except that the chemical agent supply control was performed. Since the predicted precipitation location was inside the distillation column 23, control was performed to increase the chemical agent supply rate of the top pump-around 24A (arrow Z) more than that of the top tower pipe (arrow Y). As a result, as shown in the above table and Figure 4, a monitoring result was obtained that the chloride ion concentration of the top pump-around 24A was higher than that of the accumulator 27. That is, it was confirmed that, by the above prediction and the supply control of the chemical agent, good salt dispersion was achieved inside the distillation column 23 and the deposition of dirt was suppressed.

Claims

1. A method for supplying a surfactant to a distillation facility in an oil refining process, comprising: monitoring the operation of the distillation facility, and controlling the supply rate of the surfactant according to at least one deposition location of an ammonium salt and an amine salt in the distillation facility predicted based on the monitoring, the surfactant is an oil-soluble surfactant having a nitrogen-containing hydrophilic group, The control of the supply rate includes increasing the supply rate of the surfactant supplied to the top of the distillation column when at least one deposition location of the ammonium salt and the amine salt is predicted to be inside the distillation column.

2. The method according to claim 1, wherein the monitoring includes measuring at least one selected from the group consisting of temperature, pressure, naphtha flow rate, naphtha specific gravity, naphtha distillation characteristics, drain water volume, drain water chloride ion concentration, drain water ammonium ion concentration, and drain water pH inside the distillation column.

3. The method according to claim 1 or 2, further comprising supplying the surfactant to two or more locations in one distillation facility, and the control includes controlling the supply rate of the surfactant so as to balance the supply amounts among a plurality of supply locations in the one distillation facility.

4. A method for suppressing the deposition of dirt caused by inorganic salts contained in crude oil in a distillation facility of an oil refining process, comprising: monitoring the operation of the distillation facility, and controlling the supply rate of a surfactant according to at least one deposition location of an ammonium salt and an amine salt in the distillation facility predicted based on the monitoring, the surfactant is an oil-soluble surfactant having a nitrogen-containing hydrophilic group, The method for controlling the supply rate includes increasing the supply rate of the surfactant supplied to the top of the distillation column when it is predicted that the deposition location of at least one of the ammonium salt and the amine salt is inside the distillation column. **Claim 5** A method for suppressing corrosion of distillation equipment in a petroleum refining process, comprising: monitoring the operation of the distillation equipment, and controlling the supply rate of the surfactant according to the predicted deposition location of at least one of the ammonium salt and the amine salt in the distillation equipment based on the monitoring, wherein the surfactant is an oil-soluble surfactant having a nitrogen-containing hydrophilic group, and the method for controlling the supply rate includes increasing the supply rate of the surfactant supplied to the top of the distillation column when it is predicted that the deposition location of at least one of the ammonium salt and the amine salt is inside the distillation column. **Claim 6** An automatic supply system of a chemical agent for suppressing the deposition of dirt caused by inorganic salts contained in crude oil in distillation equipment in a petroleum refining process, comprising: a supply line for supplying the chemical agent to the distillation equipment; a monitoring unit for monitoring the operation of the distillation equipment; and a control unit for controlling the supply rate of the chemical agent through the supply line, wherein the control unit is configured to predict the deposition location of at least one of the ammonium salt and the amine salt based on the monitoring result of the monitoring unit and control the supply of the chemical agent through the supply line accordingly, and the method for controlling the supply rate includes increasing the supply rate of the surfactant supplied to the top of the distillation column when it is predicted that the deposition location of at least one of the ammonium salt and the amine salt is inside the distillation column. **Claim 7** The system according to claim 6 for performing the method according to any one of claims 1 to 5.

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