Method of operating reactive monomer storage tank

Abstract

The present invention relates to a method for operating a reactive monomer storage tank in which a reactive monomer is stored, the method comprising the steps of: supplying a lower discharge stream of the storage tank including a liquid reactive monomer and a polymerization inhibitor to a first heat exchanger to cool the lower discharge stream, and then refluxing the lower discharge stream to a liquid region of the storage tank; and supplying an upper discharge stream of the storage tank including a gaseous reactive monomer to a second heat exchanger through a pressurizing device to cool the upper discharge stream, and then refluxing the upper discharge stream to a gaseous region of the storage tank.

Description

Method of operating a reactive monomer storage tank

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2024-0119625, filed September 3, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present application relates to an operating method of a reactive monomer storage tank, and more specifically, to an operating method capable of stably suppressing a polymerization reaction in a storage tank storing a reactive monomer even under changes in the external environment.

[0005] At reactive monomer production plants, reactive monomers are transported, stored, managed, and shipped in storage tanks. However, occasionally, before product shipment, polymerization reactions within the storage tanks can increase the polymer content, causing product specifications to deviate, hindering sales.

[0006] Furthermore, polymerization of reactive monomers can occur at a much faster rate than usual under certain conditions, such as high temperatures or insufficient polymerization inhibitors. This polymerization is exothermic, releasing a significant amount of heat during the polymerization process. This heat can lead to runaway polymerization. Furthermore, the rapid heat release can cause monomers or flammable materials heated above their boiling points to vaporize, forming an explosive vapor cloud that, if ignited, can lead to an explosion.

[0007] A representative example of such a reactive monomer is styrene monomer (SM). Styrene monomer is a major basic oil in petrochemicals, used as a raw material for the synthesis of plastics such as polystyrene (PS), SBR, and ABS. The double bonds (vinyl groups) within the styrene monomer structure readily polymerize in the presence of light, heat, peroxides, or catalysts, making it a useful raw material for polymer synthesis. However, due to its high reactivity, styrene monomer can undergo unintended polymerization, i.e., self-polymerization, in storage tanks during storage and transportation. Periodic monitoring of styrene monomer temperature, polymerization inhibitors, and polymer concentrations to appropriately control this is crucial from a product management perspective.

[0008] In factories that produce and manage reactive monomers such as styrene monomer, the temperature and concentration of polymerization inhibitors within the storage tank are critical factors that are managed and operated accordingly. However, unintended temperature increases can occur due to external factors. Temperature fluctuations caused by factors such as ambient temperature can lead to polymerization and the formation of polymers, which not only cause financial losses but can also lead to serious accidents. Furthermore, if the gaseous reactive monomer generated at high temperatures condenses on the inner walls of the storage tank due to external factors such as ambient temperature, it can stagnate without any flow, resulting in the formation of solid polymers (oxides).

[0009] Therefore, there is a need to develop a technology that can stably suppress polymerization reaction and prevent polymer formation even when the external environment changes during operation of a storage tank storing a reactive monomer.

[0010] The problem to be solved in the present disclosure is to provide a method for suppressing polymerization of a reactive monomer and preventing polymer formation by stably operating a storage tank storing a reactive monomer in response to changes in the external environment, in order to solve the problem mentioned in the above background art.

[0011] However, the problems to be solved by the present disclosure are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0012] According to one embodiment of the present disclosure for solving the above problem, a method for operating a reactive monomer storage tank is provided, comprising: a step of supplying a lower discharge stream of the storage tank containing a liquid reactive monomer and a polymerization inhibitor to a first heat exchanger to cool the stream, and then refluxing the stream to a liquid region of the storage tank; and a step of supplying an upper discharge stream of the storage tank containing a gaseous reactive monomer to a second heat exchanger through a pressurizing device to cool the stream, and then refluxing the stream to a gaseous region of the storage tank.

[0013] According to the operating method of the reactive monomer storage tank of the present disclosure, the reactive monomer can be stably stored by controlling the temperature, pressure, and / or oxygen concentration of the liquid phase region and gas phase region within the storage tank in response to changes in the external environment.

[0014] More specifically, it is possible to prevent runaway polymerization caused by heat generation by suppressing the polymerization reaction of a liquid reactive monomer in a storage tank, and to suppress the condensation of evaporated gaseous reactive monomer on the inner wall of the storage tank to produce a solid polymer, thereby preventing accidents such as vapor leakage and explosion.

[0015] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0016] FIG. 1 is a process flow diagram of a method for operating a reactive monomer storage tank according to one embodiment of the present disclosure.

[0017] FIG. 2 is a process flow diagram of a method for operating a reactive monomer storage tank according to one embodiment of the present disclosure.

[0018] Figure 3 is a process flow diagram of a conventional method for operating a reactive monomer storage tank according to a comparative example.

[0019] The terms or words used in the description and claims of the present disclosure should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present disclosure, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0020] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0021] The singular form of a noun corresponding to an item may include one or more of said items, unless the relevant context clearly indicates otherwise.

[0022] In this disclosure, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof.

[0023] The term “and / or” includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0024] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish one component from another and do not qualify the components in any other respect (e.g., importance or order).

[0025] In addition, terms such as 'front', 'rear', 'top', 'bottom', 'side', 'left', 'right', 'upper', and 'lower' used in the present disclosure are defined based on the drawings, and the shape and position of each component are not limited by these terms.

[0026] The terms “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the present disclosure, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0027] When a component is said to be “connected,” “coupled,” “supported,” or “in contact with” another component, this includes not only cases where the components are directly connected, coupled, supported, or in contact, but also cases where the components are indirectly connected, coupled, supported, or in contact through a third component.

[0028] When we say that a component is “on” another component, this includes not only cases where the component is in contact with the other component, but also cases where there is another component between the two components.

[0029] In addition, the terms "about", "substantially", etc. used in this disclosure are used in the sense of or close to the numerical value when manufacturing and material tolerances inherent to the meanings mentioned are presented, and are used to prevent unscrupulous infringers from unfairly using the disclosure contents in which exact or absolute numerical values ​​are mentioned to aid understanding of this disclosure.

[0030] The term "stream" as used herein may refer to the flow of fluid within a process, and may also refer to the fluid itself flowing within a pipe. Specifically, the stream may refer to both the fluid itself flowing within the pipe connecting each device and the flow of the fluid. Furthermore, the fluid may include one or more components of gas, liquid, and solid.

[0031] The term "upper" as used herein, unless otherwise specified, refers to a point 0% to 20% in height downward from the top of the device, and may specifically refer to the top (top). In addition, the term "lower" refers to a point 80% to 100% in height downward from the top of the device, and may specifically refer to the bottom (bottom).

[0032] Additionally, “pressure” as referred to in the present disclosure means gauge pressure measured based on atmospheric pressure.

[0033] Hereinafter, a method for operating a reactive monomer storage tank of the present disclosure will be described with reference to the attached drawings, but the attached drawings are exemplary and the scope of the method for operating the reactive monomer storage tank is not limited thereto.

[0034] The present disclosure relates to a method for operating a storage tank for storing a reactive monomer, and FIGS. 1 and 2 illustrate a process flow of operating a storage tank according to one embodiment of the present disclosure.

[0035] Fig. 3 illustrates a conventional reactive monomer storage tank operation process flow. Referring to Fig. 3, in the past, in order to prevent accidents due to runaway polymerization during storage of a reactive monomer (M), a blanket treatment was performed by supplying an inert gas (IG) such as nitrogen to the gas phase region (12) of the storage tank (10), controlling the pressure within the storage tank (10) by controlling a breather valve, preventing a temperature rise of the liquid reactive monomer with a heat exchanger (21), and suppressing polymer production by injecting a polymerization inhibitor and managing the amount of dissolved oxygen.

[0036] Despite the management of the operating conditions of the storage tank (10) as described above, the temperature of the gaseous region (12) within the storage tank (10) shows a tendency similar to the outside temperature. Accordingly, the reactive monomer repeatedly vaporizes and condenses due to the daily temperature difference, and in the gaseous region (12) without a polymerization inhibitor, the risk of explosion increases as the gaseous reactive monomer increases with the rise in temperature, and the reactive monomer condensed on the inner wall of the storage tank forms a dead zone where it stagnates without a flow, which causes the problem of forming a solid polymer (oxide). Furthermore, if a polymer is formed on the inner wall of the storage tank (10) or an opening for vapor (gas) or liquid inlet and outlet, pressure control or temperature control may become difficult, which may deteriorate the operational stability of the storage tank.

[0037] In order to solve such a problem, the present disclosure aims to improve the operating stability of a reactive monomer storage tank by controlling both the temperature of the liquid region and the temperature of the gas region in addition to the conventional operating method.

[0038] A method for operating a reactive monomer storage tank according to one embodiment of the present disclosure comprises the steps of: supplying a lower discharge stream of the storage tank (10) storing a reactive monomer, which includes a liquid reactive monomer (M) and a polymerization inhibitor, to a first heat exchanger (21), cooling the stream, and then refluxing the stream into a liquid region (11) of the storage tank; and supplying an upper discharge stream of the storage tank, which includes a gaseous reactive monomer, to a second heat exchanger (22) through a pressurizing device (30), cooling the stream, and then refluxing the stream into a gaseous region (12) of the storage tank.

[0039] Referring to Fig. 1, the bottom discharge stream of the storage tank containing the liquid reactive monomer (M) and the polymerization inhibitor is supplied to the first heat exchanger (21) to be cooled, and then refluxed to the liquid region (11) of the storage tank. In addition, a portion of the bottom discharge stream of the storage tank (10) may be branched and discharged as needed, and the newly received reactive monomer (M) may be joined to the cooled bottom discharge stream and supplied to the storage tank.

[0040] The above reactive monomer (M) is a substance that is easily polymerized by light, heat, catalysts, etc., and is mainly used as a polymer raw material, and can cause self-polymerization during storage and transportation. Examples of the above reactive monomer include styrene, acrylonitrile, and butadiene.

[0041] In addition, the reactive monomer may exist mostly in a liquid phase within the storage tank (10) and some may exist in a gas phase. Here, the interior of the storage tank (10) may be divided into a liquid phase region (11) and a gas phase region (12) based on the liquid level of the liquid reactive monomer.

[0042] In one embodiment, the styrene monomer is a colorless or yellowish flammable liquid with an irritating odor, and is used as a monomer for the polymerization of specific polymer compounds such as polystyrene (PS) resin, ABS resin, unsaturated polyester resin, and synthetic rubber (SBR). The styrene monomer can be polymerized using various initiators such as free radicals, cations, anions, and coordination mechanisms, and polymerization can also occur by heat in the absence of impurities. In addition, when the polymerization inhibitor is below an appropriate ratio, the styrene monomer can self-polymerize, and the heat generated by the polymerization reaction can increase the temperature and pressure of the equipment. In addition, the styrene monomer reacts with oxidizing agents, peroxides, strong acids, etc., and copper and copper alloys should be avoided, and rust can promote polymerization. Additionally, styrene monomer has the characteristic of emitting acrid vapors during thermal polymerization and generating carbon monoxide during incomplete combustion.

[0043] The above polymerization inhibitor can prevent polymerization by reacting with free radicals of a growing chain of the reactive monomer when polymerization is initiated and deactivating them, or by reacting with oxides generated within the reactive monomer to inhibit polymerization, thereby acting as an antioxidant. For example, the polymerization inhibitor may include 4-tert-butylcatechol (TBC) and p-tert-butylcatechol. For example, the TBC may be added to prevent oxidative degradation of styrene and polymerization during transport and storage.

[0044] In addition, based on the total amount of reactive monomers contained in the liquid region of the storage tank, the content of the polymerization inhibitor may be 0.0005 wt% to 0.5 wt%, preferably 0.001 wt% to 0.002 wt%, and more preferably 0.001 wt% to 0.0015 wt%. By satisfying the content range, the polymerization reaction of the reactive monomer can be reduced.

[0045] The above storage tank (10) is a large-capacity storage facility for reactive monomers, and it is preferable that the internal upper structure be small and made of a smooth material to minimize the space where polymers can be formed. For example, it is preferable to use a storage tank with minimal internal beams, pipes, and crevices that can provide space for the vapor of the condensed reactive monomer to accumulate and polymerize. In addition, the storage tank must be made of a material that does not react with the reactive monomer or the polymerization inhibitor. For example, materials such as copper and copper alloys can react with the polymerization inhibitor to cause greenish contaminants and scale formation, which can act as a catalyst for the reactive monomer.

[0046] According to one embodiment, the liquid bottom discharge stream of the storage tank is cooled by the first heat exchanger (21) and refluxed into the liquid region, thereby maintaining the temperature of the liquid region within a range of -8°C to 35°C, preferably 0°C to 24°C, and more preferably 3°C to 21°C. By maintaining the temperature of the liquid region within the above range, the polymerization reaction of the reactive monomer can be suppressed.

[0047] The above first heat exchanger (21) is a heat exchanger capable of liquid-liquid heat exchange, and may be, for example, a refrigerator, and its refrigerant may include freon, ammonia, propylene, and cooling water.

[0048] According to one embodiment, the transport of the lower discharge stream of the storage tank (10) may be performed by a circulation pump provided in the pipe. In this case, if the liquid lower discharge stream is circulated and injected into the gaseous region (12), there is a possibility of explosion due to static electricity generation. Therefore, in order to prevent static electricity discharge, it is preferable to provide an inlet for the liquid stream injection at the lower part of the storage tank so that the liquid lower discharge stream is circulated only to the liquid region (11).

[0049] Additionally, an eductor (not shown) may be provided at the inlet through which the liquid lower discharge stream is refluxed. If the eductor is provided, it can help with mixing within the liquid region (11) of the storage tank, thereby improving temperature uniformity. Furthermore, if the outlet and inlet of the liquid lower discharge stream are provided in opposite directions, mixing within the liquid region (11) can be promoted.

[0050] Referring to Fig. 1, the upper discharge stream of the storage tank containing the reactive monomer of the gas phase is supplied to the second heat exchanger (22) through a pressurizing device (30) to be cooled, and then refluxed to the gas phase region (12) of the storage tank. At this time, the pressure and temperature of the gas phase region (11) within the storage tank (10) can be monitored in real time by a pressure measurement sensor (P) and a temperature measurement sensor (T), respectively, and the refrigerant of the second heat exchanger (22) can be a liquid such as water.

[0051] If necessary, the upper discharge stream of the storage tank may be branched so that some of it is returned to the storage tank (10) without passing through the second heat exchanger, and the remainder is cooled through the second heat exchanger (22) and then returned to the storage tank (10).

[0052] According to one embodiment, the upper discharge stream of the gas phase of the storage tank is cooled by the second heat exchanger (22) and refluxed into the gas phase region (12), thereby maintaining the temperature of the gas phase region within a range of 0°C to 35°C, preferably 0°C to 30°C, and more preferably 0°C to 25°C. By maintaining the temperature of the gas phase region within the above range, evaporation of the liquid reactive monomer within the storage tank can be prevented, and thus formation of a solid polymer (oxide) by the reactive monomer condensed on the inner wall of the storage tank due to the influence of the external temperature, etc. can be suppressed.

[0053] In addition, the upper gaseous discharge stream of the storage tank (10) may be transported by a pressurizing device (30). At this time, when the upper gaseous discharge stream is circulated and injected into the liquid phase region (11), the vapor may move from the liquid phase region (11) to the gas phase region (12), causing droplets to splash and causing a polymerization reaction due to droplet entrainment. Therefore, it is preferable to reflux the upper gaseous discharge stream only to the gas phase region (12) of the storage tank.

[0054] In addition, the pressure of the gaseous region (12) can be controlled by a breather valve provided on the pressurization device (30) and / or the upper part of the storage tank to release steam, and for example, the pressure of the gaseous region can be maintained within a range of 0 mmH2O to 200 mmH2O, preferably 0 mmH2O to 50 mmH2O, and more preferably 10 mmH2O to 20 mmH2O. By maintaining the pressure of the gaseous region within the above range, the temperature of the gaseous region can be controlled, and the stability of the equipment can be improved. The pressurization device (30) can be, for example, a blower or a compressor, and the breather valve can be designed to minimize the release of steam.

[0055] In addition, to prevent electrostatic accidents, etc., blanket treatment may be performed by injecting an inert gas (IG) into the gaseous region (12) of the storage tank. Specifically, referring to Fig. 1, an inert gas (IG) may be injected into the upper discharge stream of the storage tank and supplied to the gaseous region (12) of the storage tank. For example, the inert gas may include nitrogen (N2) and carbon dioxide (CO2), and the amount of the inert gas injected may be extremely small.

[0056] Meanwhile, in order for the polymerization inhibitor to work effectively in the reactive monomer, sufficient oxygen must be dissolved in the reactive monomer, and even when storing it by blanketing it with an inert gas, a sufficient oxygen concentration must be maintained. In this regard, referring to FIG. 2, by injecting air (AIR) into the upper discharge stream of the storage tank and circulating it into the gaseous region (12) of the storage tank, the dissolved oxygen concentration in the liquid region (11) and the oxygen concentration in the gaseous region (12) of the storage tank can be controlled. At this time, the dissolved oxygen concentration in the liquid region (11) and the oxygen concentration in the gaseous region (12) are measured by an oxygen concentration measuring sensor (C g, C l ) can be monitored in real time. In addition, by controlling the amount of air (AIR) supplied to the storage tank (10) in real time according to the oxygen concentration of each area confirmed accordingly, the dissolved oxygen concentration of the liquid area (11) and the oxygen concentration of the gaseous area (12) can be controlled. For example, when air (AIR) is supplied to the gaseous area of ​​the storage tank and the oxygen concentration of the gaseous area (12) increases, the dissolved oxygen concentration of the liquid area (11) can also increase.

[0057] For example, the dissolved oxygen concentration of the liquid region (11) can be adjusted to 5 ppm to 30 ppm, preferably 10 ppm to 25 ppm, and more preferably 15 ppm to 20 ppm. In addition, the oxygen concentration of the gaseous region can be adjusted to 2 vol% to 10 vol%, preferably 3 vol% to 8 vol%, and more preferably 5 vol% to 7 vol%. When the dissolved oxygen concentration of the liquid region (11) and the oxygen concentration of the gaseous region (12) are maintained within the above ranges, the polymerization inhibitor can effectively act to suppress polymer production. For example, when the oxygen concentration of the gaseous region (12) becomes lower than the lower limit range, the dissolved oxygen concentration of the liquid region (11) becomes lower than the appropriate range, and accordingly, the action of the polymerization inhibitor on the reactive monomer in the liquid phase is stopped, and the polymerization reaction can proceed.

[0058] Furthermore, the air (AIR) is supplied to the gaseous region (12) of the storage tank after passing through the second heat exchanger (22) together with the upper discharge stream of the gaseous region, thereby minimizing the temperature change in the gaseous region.

[0059] In the present disclosure, additional devices such as valves, sensors, pumps, and mixers may be used if necessary.

[0060] Above, the method for operating a reactive monomer storage tank according to the present disclosure has been described and illustrated in the drawings, but the description and illustration of the drawings describe and illustrate only the core components for understanding the present disclosure, and in addition to the processes and devices described and illustrated in the drawings, processes and devices not described and illustrated separately can be appropriately applied and utilized to implement the method for operating a reactive monomer storage tank according to the present disclosure.

[0061] [Example]

[0062] Example 1

[0063] According to the process flow shown in Fig. 1, a storage tank (10) containing styrene monomer (M) was operated, and 4-tert-butylcatechol (15 ppm) was used as a polymerization inhibitor.

[0064] Specifically, referring to FIG. 1, the lower discharge stream of the storage tank containing the liquid reactive monomer and the polymerization inhibitor was supplied to the first heat exchanger (21) to be cooled, and then refluxed to the liquid region (11) of the storage tank to control the temperature of the liquid region. In addition, the upper discharge stream of the storage tank containing the gaseous reactive monomer was supplied to the second heat exchanger (22) through the pressurization device (30) to be cooled, and then refluxed to the gaseous region (12) of the storage tank to control the temperature and pressure of the gaseous region. Furthermore, nitrogen was supplied to the gaseous region (12) of the storage tank to perform blanket treatment, and the pressure of the gaseous region was additionally controlled through the breather valve at the top of the storage tank.

[0065] When the storage tank was operated according to the above Example 1, the temperature of the liquid region (11) of the storage tank was maintained within the range of -8°C to 35°C even after a long period of time, and the gas region (12) was able to maintain a desired constant temperature within the range of 0°C to 35°C and a pressure within the range of 0 mmH2O to 200 mmH2O. Accordingly, the operational stability of the storage tank was secured, and polymer formation on the inner wall of the storage tank was suppressed.

[0066] Example 2

[0067] According to the process flow shown in Fig. 2, a storage tank (10) containing styrene monomer (M) was operated, and 4-tert-butylcatechol (15 ppm) was used as a polymerization inhibitor.

[0068] Specifically, referring to FIG. 2, the dissolved oxygen concentration in the liquid region (11) and the oxygen concentration in the gaseous region (12) are measured by an oxygen concentration measuring sensor (C l , C g) was operated in the same manner as in Example 1, except that air (AIR) was supplied to the meteorological area (12) of the storage tank while monitoring in real time.

[0069] When the storage tank was operated according to the above Example 2, even after a long period of time, the liquid region (11) of the storage tank was able to maintain a temperature in the range of -8°C to 35°C and a dissolved oxygen concentration in the range of 5 ppm to 30 ppm, and the gaseous region (12) was able to maintain a desired constant temperature in the range of 0°C to 35°C, a pressure in the range of 0 mmH2O to 200 mmH2O, and an oxygen concentration in the range of 2 vol% to 10 vol%. Accordingly, the operational stability of the storage tank was secured, and polymer formation on the inner wall of the storage tank was suppressed.

[0070] Comparative Example 1

[0071] According to the process flow shown in Fig. 3, a storage tank (10) containing styrene monomer (M) was operated, and 4-tert-butylcatechol (15 ppm) was used as a polymerization inhibitor.

[0072] Specifically, referring to FIG. 3, the storage tank was operated in the same manner as in Example 1, except that the cooling process was not performed on the upper discharge stream of the storage tank containing the gaseous reactive monomer since the pressurizing device (30) and the second heat exchanger (22) were not provided.

[0073] When the storage tank was operated according to the above Comparative Example 1, the liquid region (11) of the storage tank maintained a temperature in the range of -8°C to 35°C, but the gas region (12) was greatly affected by the outside temperature, making it difficult to maintain the desired constant temperature. Specifically, the temperature of the gas region showed a tendency similar to the outside temperature, resulting in low operating stability and difficulty in rapid temperature control.

[0074] Although exemplary embodiments of the present disclosure have been described above, the present disclosure is not limited thereto, and those skilled in the art will understand that various changes and modifications are possible within the scope and spirit of the claims set forth below.

[0075] [Explanation of symbols]

[0076] 10: Storage tank

[0077] 11: Liquid area of ​​the storage tank

[0078] 12: Meteorological area of ​​the storage tank

[0079] 21: First heat exchanger

[0080] 22: Second heat exchanger

[0081] 30: Pressurization device

[0082] P: pressure measurement sensor

[0083] T: Temperature measurement sensor

[0084] C g : Oxygen concentration measurement sensor in the meteorological field

[0085] C l : Dissolved oxygen concentration measurement sensor in liquid region

[0086] M: reactive monomer

[0087] IG: Inert gas

Claims

1. In a storage tank storing a reactive monomer, A step of supplying the bottom discharge stream of the storage tank containing the liquid reactive monomer and polymerization inhibitor to the first heat exchanger to cool it and then refluxing it to the liquid region of the storage tank; and A method for operating a reactive monomer storage tank, comprising the step of supplying an upper discharge stream of the storage tank containing a gaseous reactive monomer to a second heat exchanger through a pressurizing device to cool it, and then refluxing it to the gaseous region of the storage tank.

2. In paragraph 1, A method for operating a reactive monomer storage tank, comprising injecting air into an upper discharge stream of the storage tank to control the dissolved oxygen concentration in the liquid phase region and the gas phase region of the storage tank.

3. In paragraph 2, The dissolved oxygen concentration in the liquid region of the above storage tank is controlled to 5 ppm to 30 ppm, A method for operating a reactive monomer storage tank, wherein the oxygen concentration in the gaseous region of the storage tank is controlled to 2 vol% to 10 vol%.

4. In paragraph 1, Maintain the temperature of the liquid region of the above storage tank within the range of -8℃ to 35℃, A method for operating a reactive monomer storage tank, wherein the temperature of the gaseous region of the storage tank is maintained within a range of 0°C to 35°C.

5. In paragraph 1, A method for operating a reactive monomer storage tank, wherein the pressure in the gaseous region of the storage tank is maintained within a range of 0 mmH2O to 200 mmH2O.

6. In paragraph 1, A method for operating a reactive monomer storage tank, comprising injecting an inert gas into the upper discharge stream of the storage tank and supplying it to the gas phase region of the storage tank.

7. In paragraph 6, A method for operating a reactive monomer storage tank, wherein the inert gas comprises at least one selected from nitrogen and carbon dioxide.

8. In paragraph 1, A method for operating a reactive monomer storage tank, wherein the reactive monomer is selected from styrene, acrylonitrile and butadiene.

9. In paragraph 1, A method for operating a reactive monomer storage tank, wherein the polymerization inhibitor comprises at least one selected from 4-tert-butylcatechol and p-tert-butylcatechol.

10. In paragraph 1, A method for operating a reactive monomer storage tank, wherein the pressurizing device is a blower or a compressor.

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