Reactor-cleaning method and system

Abstract

The present invention relates to a reactor-cleaning method and system and, more specifically, to a cleaning method and system which are capable of effectively and quickly cleaning a polymer that has been fouled in a reactor and a peripheral device by operating one or more heating devices, and preventing pipe plugging due to melted polymers in a cleaning solvent that is transferred after cleaning.

Description

Reactor cleaning method and system

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0174487, filed December 5, 2023, and Korean Patent Application No. 10-2024-0086163, filed July 1, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a method and system for cleaning a reactor, and more particularly, to a cleaning method and system capable of effectively and quickly cleaning fouled polymers in a reactor and peripheral devices, and preventing plugging of pipes by molten polymers in a cleaning solvent transported after cleaning.

[0005] Alpha-olefins are widely used commercially as important substances used as comonomers, detergents, lubricants, and plasticizers. In particular, 1-hexene and 1-octene are widely used as comonomers to control the density of linear low-density polyethylene (LLDPE) during the production of polyethylene.

[0006] Linear alpha olefins such as the above 1-hexene and 1-octene are typically produced through an oligomerization reaction of ethylene. The oligomerization reaction of ethylene is carried out by an oligomerization reaction (trimerization reaction or tetramerization reaction) of ethylene using ethylene as a reactant in the presence of a catalyst. The reaction product produced through the reaction may include a multi-component hydrocarbon mixture containing the desired 1-hexene and 1-octene, as well as polymers that may be produced as by-products during the catalytic reaction. Such polymers float in the liquid reaction medium in the reactor, and over time, they accumulate in the reactor due to fouling, which causes them to build up to a certain thickness, requiring the operation of the reactor to be stopped and the reactor and its peripheral devices to be cleaned.

[0007] More specifically, the polymers produced as side reactions of the above oligomerization reaction can foul and remain for long periods of time within the reactor and surrounding devices, requiring chemical cleaning, such as hot water, to remove them. However, even with regular cleaning, the cleaning time may be long depending on the characteristics of the fouled polymers, and conventional techniques may not completely clean the device. In this way, if the device is not completely cleaned, normal process progress may be difficult even after cleaning.

[0008] For example, as illustrated in Fig. 1, it is common to preheat the cleaning solution with a heat exchanger (230) and then supply it to the reactor (100), which is the device to be cleaned, so that the polymer fouled inside is melted in the high-temperature cleaning solution, and then the cleaning solution containing the melted polymer is discharged to the outside of the device. At this time, if the cleaning solution containing the melted polymer is lowered below a certain temperature within the transport pipe due to external heat loss or other causes, problems such as plugging that blocks the transport pipe and valves due to the adhesiveness of the polymer may occur, and thus, there is a need to improve such problems.

[0009] The problem to be solved in the present invention is to provide a method and system that can effectively clean a reactor, piping, and peripheral devices that are fouled by polymers generated during a reaction, in order to solve the problem mentioned in the technology that is the background of the invention.

[0010] In addition, the reactor cleaning method and system according to one embodiment of the present invention can prevent plugging in a transfer pipe during a cleaning process and remove fouled polymers within the device in a short period of time with improved cleaning efficiency.

[0011] However, the problems that the present invention seeks to solve 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 invention for solving the above problem, a method for cleaning a reactor is provided, including: a step of supplying a cleaning solvent from a cleaning solvent supply unit to a reactor through a cleaning solvent supply line to partially fill the interior of the reactor; a step of heating the cleaning solvent within the reactor; and a step of additionally supplying a cleaning solvent from the cleaning solvent supply unit to the reactor through the cleaning solvent supply line to fill the interior of the reactor, and transferring a cleaning solvent stream containing a polymer to the cleaning solvent supply unit through a cleaning solvent discharge line connected to the upper portion of the reactor.

[0013] Additionally, the step of heating the washing solvent within the reactor may include supplying the bottom discharge stream of the reactor to one or more heating devices and then refluxing it to the side of the reactor.

[0014] According to one embodiment of the present invention, a reactor cleaning system is provided, including: a cleaning solvent supply unit that receives a cleaning solvent from the outside, stores and preheats the cleaning solvent, is connected to at least one of the lower part and the side of the reactor through a cleaning solvent supply line, supplies the cleaning solvent, and is connected to the upper part of the reactor through a cleaning solvent discharge line to recover the cleaning solvent discharged from the reactor; and a first heating device that is connected to one side of the reactor through a first heating circulation line and heats the cleaning solvent in the reactor using steam as a heat source.

[0015] In addition, an auxiliary circulation line connecting the washing solvent supply line and the washing solvent discharge line is provided, one side of the auxiliary circulation line is connected between a valve provided in the washing solvent supply line and the washing solvent supply unit, and the other side of the auxiliary circulation line can be connected between a valve provided in the washing solvent discharge line and the washing solvent supply unit.

[0016] A reactor cleaning method and system according to one embodiment of the present invention has the effect of effectively cleaning a reactor, piping, and peripheral devices that are fouled by polymers generated during a reaction.

[0017] In addition, according to the reactor cleaning method and system of the present invention, there is an advantage in that plugging can be prevented from occurring in the transfer pipe during the cleaning process, and fouled polymers within the device can be removed in a short period of time with improved cleaning efficiency.

[0018] More specifically, the reactor cleaning method and system according to the present invention can effectively remove polymers fouled on the inner wall of the reactor by preventing heat loss and creating turbulence within the reactor when the cleaning solvent circulates by operating one or more heating devices.

[0019] The effects that can be obtained from this invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art to which the present invention pertains from the description below.

[0020] Figure 1 is a process flow diagram of a conventional reactor cleaning method.

[0021] Figure 2 is a process flow diagram of a reactor cleaning method according to one embodiment of the present invention.

[0022] Figure 3a is a process flow diagram of a reactor cleaning method according to one embodiment of the present invention, showing a process of partially filling the interior of a reactor with a cleaning solvent.

[0023] Figure 3b is a process flow diagram of a reactor cleaning method according to one embodiment of the present invention, showing a process of heating a cleaning solvent inside a reactor.

[0024] Figure 3c is a process flow diagram of a reactor cleaning method according to one embodiment of the present invention, showing a process of additionally supplying a cleaning solvent to the reactor and circulating a cleaning solvent stream.

[0025] Figure 4a is a process flow diagram of a reactor cleaning method according to one embodiment of the present invention, showing a process of partially filling the interior of a reactor with a cleaning solvent.

[0026] Figure 4b is a process flow diagram of a reactor cleaning method according to one embodiment of the present invention, showing a process of heating a cleaning solvent inside a reactor.

[0027] Figure 4c is a process flow diagram of a reactor cleaning method according to one embodiment of the present invention, showing a process of additionally supplying a cleaning solvent to the reactor and circulating a cleaning solvent stream.

[0028] The terms or words used in the description and claims of the present invention 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 invention, 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.

[0029] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0030] 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.

[0031] 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.

[0032] The term "and / or" includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0033] 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).

[0034] In addition, terms such as 'front', 'rear', 'top', 'bottom', 'side', 'left', 'right', 'upper', and 'lower' used in this application are defined based on the drawings, and the shape and position of each component are not limited by these terms.

[0035] Terms such as "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.

[0036] 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.

[0037] 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.

[0038] In addition, the terms "about", "substantially", etc. used herein 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 the present invention.

[0039] The term "stream" as used herein may refer to the flow of fluid within a process, or may 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.

[0040] 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).

[0041] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

[0042] In addition, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description is omitted.

[0043] According to the present invention, a reactor cleaning method and a reactor cleaning system are provided.

[0044] A reactor cleaning method according to one embodiment of the present invention may include the steps of: supplying a cleaning solvent (CS) from a cleaning solvent supply unit (200) to a reactor (100) through a cleaning solvent supply line (L13) to partially fill the interior of the reactor (100); heating the cleaning solvent (CS) within the reactor (100); and additionally supplying a cleaning solvent (CS) from the cleaning solvent supply unit (200) to the reactor (100) through the cleaning solvent supply line (L13) to fill the interior of the reactor (100), and transferring a cleaning solvent stream containing a polymer to the cleaning solvent supply unit (200) through a cleaning solvent discharge line (L14) connected to the upper portion of the reactor (100).

[0045] In addition, the step of heating the washing solvent (CS) in the reactor (100) may include supplying the lower discharge stream of the reactor (100) to one or more heating devices (110, 120, 130) and then refluxing it to the side of the reactor (100).

[0046] In one embodiment, the step of heating the washing solvent (CS) in the reactor (100) may include supplying the first lower discharge stream of the reactor (100) to the first heating device (110) and then refluxing it to the first reflux inlet located at one side of the reactor (100), and supplying the second lower discharge stream of the reactor (100) to the second heating device (120) and then refluxing it to the second reflux inlet located at the other side of the reactor (100). The reactor washing system according to one embodiment of the present invention is a washing solvent system that receives a washing solvent (CS) from the outside, stores it, and preheats it, supplies the washing solvent (CS) by connecting it to at least one of the lower part and the side of the reactor (100) through a washing solvent supply line (L13), and recovers the washing solvent (CS) discharged from the reactor by connecting it to the upper part of the reactor (100) through a washing solvent discharge line (L14). It may include a supply unit (200); a first heating device (110) connected to one side of the reactor (100) through a first heating circulation line (L21) and heating a washing solvent (CS) in the reactor using steam as a heat source; and a second heating device (120) connected to the other side of the reactor (100) through a second heating circulation line (L22) and heating a washing solvent (CS) in the reactor using steam as a heat source.

[0047] In addition, the length of the first heating device (110) is 1.5 to 2 times the length of the second heating device (120), and the reflux inlet of the first heating device (110) can be located at a lower height than that of the second heating device (120).

[0048] In addition, an auxiliary circulation line (L12) is provided that connects the washing solvent supply line (L13) and the washing solvent discharge line (L14), and one side of the auxiliary circulation line is connected between a valve (302) provided in the washing solvent supply line and the washing solvent supply unit (200), and the other side of the auxiliary circulation line can be connected between a valve (303) provided in the washing solvent discharge line and the washing solvent supply unit (200).

[0049] According to one embodiment of the present invention, the reactor (100) may be an ethylene oligomerization reactor. Specifically, it is widely used commercially as an important material used as a comonomer, detergent, lubricant, plasticizer, etc., and in particular, 1-hexene and 1-octene are alpha olefins that are widely used as comonomers for controlling the density of polyethylene when producing linear low-density polyethylene (LLDPE). These alpha olefins can be produced through an ethylene oligomerization reaction.

[0050] The above ethylene oligomerization reaction can be carried out by using ethylene as a reactant and undergoing a trimerization reaction or a tetramerization reaction in the presence of a catalyst. The above oligomerization reaction can refer to a reaction in which monomers are oligomerized. Depending on the number of monomers polymerized, it is called trimerization or tetramerization, and this is collectively called multimerization.

[0051] The catalyst used in the above ethylene oligomerization reaction may include a transition metal source. The transition metal source may be, for example, a compound including at least one selected from the group consisting of chromium (III) acetylacetonate, chromium (III) chloride tetrahydrofuran, chromium (III) 2-ethylhexanoate, chromium (III) tris(2,2,6,6-tetramethyl-3,5-heptaneindionate), chromium (III) benzoylacetonate, chromium (III) hexafluoro-2,4-pentaneindionate, chromium (III) acetate hydroxide, chromium (III) acetate, chromium (III) butyrate, chromium (III) pentanoate, chromium (III) laurate, and chromium (III) stearate.

[0052] The above-mentioned cocatalyst may include, for example, at least one selected from the group consisting of trimethyl aluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, ethylaluminum sesquichloride, diethylaluminum chloride, ethylaluminum dichloride, methylaluminoxane, modified methylaluminoxane, and borate.

[0053] In this way, in the process of oligomerizing ethylene monomers in the presence of a catalyst, in addition to the oligomer product, a polymer such as polyethylene may be produced as a byproduct during the catalytic reaction. The polymer floats in the liquid reaction medium within the reactor, and over time, there is a problem in that the polymer (P) accumulates on the inner walls of the reactor, etc., and a fouling phenomenon occurs in which the polymer (P) builds up to a certain thickness. In this case, the reactor must be shut down and the reactor and its auxiliary equipment must be cleaned.

[0054] In the past, as shown in Fig. 1, in order to clean a reactor (100) fouled by a polymer, a method was used in which a high-temperature solvent preheated to a high temperature using a heater (230) was introduced from a cleaning solvent storage tank (210) to the reactor (100) by a pump (220) and circulated. In this case, in the initial stage of the cleaning process of the reactor (100), the polymer is melted in the high-temperature cleaning solvent. At this time, after cleaning the reactor, the temperature inside the transfer pipe is lowered due to external heat loss and other causes during the transfer process of the cleaning solvent in which the polymer is melted. Furthermore, due to the heat loss that occurred during the transfer process, the adhesiveness of the polymer melted in the cleaning solvent is increased, and this causes a problem in that a plugging phenomenon occurs in the transfer pipe and valves, etc.

[0055] Accordingly, the present invention aims to provide a reactor cleaning method capable of cleaning a reactor in a short period of time by circulating a cleaning solvent between a cleaning solvent supply unit (200) storing the cleaning solvent and a reactor (100) while maintaining a high temperature in order to effectively clean a reactor and peripheral devices fouled by the polymer, and by optimizing the operating conditions and cleaning method at the same time to improve the cleaning rate. In addition, when cleaning a reactor using the method according to the present invention, the cleaning operation time is reduced, and thus the annual plant operating rate is increased, which can improve production. Furthermore, the cleaning cost is reduced, the reaction normalization time after cleaning is shortened, so that the reaction stability can be improved, and the temperature of the cleaning solvent can be maintained above a certain level to prevent plugging in the pipe.

[0056] A method for washing a reactor according to one embodiment of the present invention, as shown in FIGS. 3A and 4A, supplies a washing solvent (CS) from a washing solvent supply unit (200) to a reactor (100) through a washing solvent supply line (L13) to partially fill the interior of the reactor (100) in order to inject the washing solvent (CS) into the reactor immediately after the reaction is completed.

[0057] According to one embodiment of the present invention, a washing solvent (CS) may be used to wash the reactor (100). For example, the washing solvent (CS) may include at least one selected from the group consisting of n-pentane, n-hexane, n-heptane, n-decane, cyclohexane, methyl cyclohexane, benzene, xylene, toluene, ethylbenzene, chlorobenzene, dichlorobenzene, and trichlorobenzene. As a specific example, the washing solvent (CS) may be methyl cyclohexane, toluene, or n-decane.

[0058] The above washing solvent supply unit (200) includes a washing solvent storage tank (210) and, if necessary, may further include a pump (220) and a heater (230).

[0059] According to one embodiment of the present invention, the washing solvent (CS) may be supplied to the washing solvent storage tank (210) of the washing solvent supply unit (200), and the pump (220) and the heater (230) may be operated to preheat the washing solvent (CS). Specifically, the washing solvent (CS) supplied to the washing solvent storage tank (210) may be discharged through the lower discharge line (L10) of the washing solvent storage tank, and may be preheated while circulating through the preheating circulation line (L11) branched from the lower discharge line (L10) of the washing solvent storage tank and connected to the washing solvent storage tank (210). For example, by discharging a washing solvent stream through the preheating circulation line (L11), circulating the washing solvent stream to the washing solvent storage tank (210) using a pump (220), and preheating the washing solvent (CS) to a desired temperature using a heater (230) provided in the preheating circulation line (L11), the temperature of the washing solvent (CS) can be maintained while simultaneously increasing the temperature of the transport pipe.

[0060] The above preheating circulation line (L11) may be equipped with a first valve (301). The first valve (301) may be fully opened when preheating the washing solvent stream, and may be throttled to control the flow rate when supplying the washing solvent stream to the washing solvent supply line (L13).

[0061] The temperature of the preheated washing solvent stream circulating through the preheating circulation line (L11) may be, for example, 140°C or higher, 145°C or higher, or 150°C or higher, and 160°C or lower, 165°C or lower, or 170°C or lower. When the reactor (100) is washed after preheating the washing solvent (CS) within the above range, the fouled polymer (P) is sufficiently swollen and can be easily removed through the circulation of the washing solvent (CS).

[0062] According to one embodiment of the present invention, a washing solvent supply line (L13) for supplying a washing solvent may be connected to the lower part of the reactor (100), and a washing solvent discharge line (L14) for discharging the washing solvent may be connected to the upper part of the reactor (100). In addition, the washing solvent supply line (L13) and the washing solvent discharge line (L14) are connected to a washing solvent supply unit (200), and due to this structure, the washing solvent (CS) can be circulated between the reactor (100) and the washing solvent supply unit (200).

[0063] According to one embodiment of the present invention, the washing solvent stream may be supplied from the washing solvent supply unit (200) to at least one of the lower and side portions of the reactor (100) to partially fill the interior of the reactor (100). Specifically, the washing solvent stream discharged through the lower discharge line (L10) of the washing solvent storage tank may be supplied to the reactor (100) through the washing solvent supply line (L13).

[0064] The lower discharge line (L10) of the washing solvent storage tank connected to the lower portion of the washing solvent storage tank (210) may be branched into the above-described preheating circulation line (L11) and the washing solvent supply line (L13), and the washing solvent stream may be supplied to the reactor (100) through the washing solvent supply line (L13). At this time, the washing solvent supply line (L13) may mean a line connected from the lower discharge line (L10) of the washing solvent storage tank to the reactor (100).

[0065] A second valve (302) may be provided in the washing solvent supply line (L13) adjacent to the lower discharge line (L10) of the washing solvent storage tank, and a third valve (303) may be provided in the washing solvent discharge line (L14). The second valve (302) and the third valve (303) may be closed to preheat the washing solvent stream or to isolate the reactor (100) when heating the washing solvent in the reactor, which will be described later, and may be opened when supplying the washing solvent (CS) to the reactor (100) or circulating the washing solvent stream.

[0066] The washing solvent stream discharged from the washing solvent supply unit (200) may be supplied to the lower part of the reactor (100), to the side, or to the lower and side parts simultaneously. At this time, the lower part of the reactor (100) may mean the lowest part of the reactor (100), and the side of the reactor (100) may mean 5% or more, 6% or more, or 7% or more and 18% or less, 19% or less, or 20% or less of the total height of the reactor (100), when the lowest part of the reactor (100) is 0% and the upper part is 100%. When the washing solvent (CS) is supplied to the side of the reactor (100) within the above range, the cleaning power of the polymer (P) accumulated on the wall surface of the reactor (100) and auxiliary equipment such as sensors can be improved.

[0067] Specifically, even when the washing solvent stream discharged from the washing solvent supply unit (200) is supplied to the lower and side of the reactor (100), the washing of the reactor (100) can be smoothly performed, and when the washing solvent stream is supplied to the lower and side of the reactor (100) simultaneously, the flow direction of the washing solvent (CS) within the reactor (100) is continuously changed, so that the washing power for the polymer (P) accumulated in the lower and wall surfaces of the reactor (100) as well as in the additional equipment such as a sensor installed within the reactor (100) can be improved.

[0068] At this time, it is preferable that the washing solvent (CS) partially filled inside the reactor be filled to a certain level or higher so that it can sufficiently submerge up to the part where polymer fouling is expected, as shown in FIGS. 3b and 4b. For example, the washing solvent (CS) may be filled inside the reactor (100) at about 50% by volume or more, or 55% by volume or more, and 65% by volume or less, or 70% by volume or less. The washing solvent must be filled inside the reactor within the above range so that the fouled polymer (P) can be sufficiently submerged in the washing solvent (CS), and also the washing efficiency can be improved by melting the polymer (P) with the washing solvent that is heated in a subsequent process. Specifically, the polymer mainly accumulates and fouls on the inner wall of the inner region of the reactor maintained for the residence time of reactants such as monomers during the operation of the reactor. Therefore, by filling the inside of the reactor to a level where the polymer fouled on the inner wall of the reactor is sufficiently submerged before circulating the washing solvent (CS) and then heating the reactor, the heating time can be shortened while increasing the polymer removal efficiency.

[0069] According to one embodiment of the present invention, as shown in FIGS. 3b and 4b, the washing solvent (CS) in the partially filled reactor (100) can be heated.

[0070] Specifically, one or more heating devices for heating the washing solvent (CS) inside the reactor (100) may be provided outside the reactor. For example, the one or more heating devices may include one heating device (110) as shown in FIG. 2, or may include a first heating device (110) and a second heating device (120) as shown in FIGS. 3a to 3c, and may further include a third heating device (130) as shown in FIGS. 4a to 4c, if necessary.

[0071] As described above, by supplying a washing solvent stream to partially fill the reactor, and closing the second valve (302) and the third valve (303) to isolate the reactor, one or more heating devices provided outside the reactor can be operated to perform thermosiphon hot flushing for a predetermined period of time. At this time, by simultaneously operating one or more heating devices designed in different sizes, it is possible to expect the effect of rapidly increasing the temperature of the washing solvent filled in the reactor and simultaneously melting the fouled polymer (P) in a short period of time by the thermosiphon mixing effect. In addition, even if the temperature of the washing solvent (CS) preheated in the washing solvent supply unit (200) decreases due to heat loss during the process of being transferred to the reactor (100), a sufficient temperature capable of melting the fouled polymer (P) can be secured through one or more heating devices provided outside the reactor.

[0072] The internal temperature of the reactor (100) can be heated from the reaction temperature immediately after the end of the reaction to a washing temperature at which the polymer can be melted. For example, through a heating process using one or more heating devices, the internal temperature of the reactor (100), i.e., the temperature of the washing solvent inside the reactor, can be increased to 140°C or higher, 145°C or higher, and 155°C or lower, or 160°C or lower, and then the temperature range can be maintained. By ensuring that the internal temperature of the reactor satisfies the temperature range during the washing process, the polymer (P) fouled on the inner wall of the reactor, etc., can be melted, enabling efficient washing.

[0073] Additionally, by partially filling the reactor immediately after the reaction and then heating it, the preparation time for cleaning, i.e., the heating time, can be shortened. For example, the preheating time inside the reactor can be within one hour.

[0074] According to one embodiment of the present invention, as shown in FIG. 2, the lower discharge stream of the reactor (100) may be supplied to a heating device (110) and then refluxed to a reflux inlet located at one side of the reactor (100). The heating device (110) may be a double pipe heat exchanger, and for example, steam may be supplied to a heat source (111) of the heating device to perform heat exchange, and then the condensate (112) of the heating device may be discharged.

[0075] According to one embodiment of the present invention, as shown in FIGS. 3a to 3c, the first lower discharge stream of the reactor (100) may be supplied to the first heating device (110) and then refluxed to the first reflux inlet located at one side of the reactor (100), and the second lower discharge stream of the reactor (100) may be supplied to the second heating device (120) and then refluxed to the second reflux inlet located at the other side of the reactor (100). The first and second heating devices (110, 120) may each independently be a double pipe heat exchanger, and for example, steam may be supplied to the heat source (111) of the first heating device to exchange heat, and then the condensate (112) of the first heating device may be discharged, and steam may be supplied to the heat source (121) of the second heating device to exchange heat, and then the condensate (122) of the second heating device may be discharged.

[0076] For example, when two or more of the above-described one or more heating devices are provided, the first heating device (110) may have the largest size so that the washing solvent stream passing through the first heating circulation line (L21) can form a high-velocity flow. For example, the first heating device (110) may have a length that is 1.5 times or more, 1.6 times or more, or 1.7 times or more, and 1.8 times or less, 1.9 times or less, or 2 times or less than the second heating device (120). Here, the length (height) of the heating device means from one side of the heating device into which the washing solvent is introduced to the other side of the heating device from which the washing solvent is discharged. Referring to FIGS. 3b and 4b, in the case of the first heating device (110) having the longest length among two or more heating devices, the washing solvent (CS) can be refluxed to the first reflux inlet located at one side of the reactor (100) to create a high-velocity flow for the washing solvent inside the reactor.

[0077] For example, when two or more of the above-described one or more heating devices are provided, the reflux inlets through which the washing solvent stream is refluxed from the two or more heating devices may be respectively positioned at different heights. Specifically, the second reflux inlet of the second heating device (120) may be positioned relatively higher than the first reflux inlet of the first heating device (110). By positioning the second reflux inlet relatively higher than the first reflux inlet, a large amount of circulation flow is formed by utilizing the high hydrostatic pressure of the washing solvent refluxed from the second reflux inlet to the reactor, thereby forming a large swirl within the reactor.

[0078] Meanwhile, in the reactor cleaning system according to one embodiment of the present invention, in addition to the second heating device (120), a third heating device (130) connected to a third heating circulation line (L23) may be further provided on the other side of the reactor.

[0079] According to one embodiment of the present invention, as shown in FIGS. 3c to 4, a portion of the second lower discharge stream of the reactor (100) may be branched and supplied to a second heating device (120) and then refluxed to a second reflux inlet located on the other side of the reactor (100), and the remaining stream may be supplied to a third heating device (130) and then refluxed to a third reflux inlet located on the other side of the reactor (100). The third heating device (130) may be a double pipe heat exchanger, and for example, steam may be supplied to a heat source (121) of the second heating device to perform heat exchange, and then a condensate (122) of the second heating device may be discharged, and then this may be used as a heat source (131) of the third heating device to perform heat exchange, and then a condensate (132) of the third heating device may be discharged.

[0080] Specifically, the second heating device (120) can generate a large flow of the washing solvent inside the reactor by using the latent heat of the steam as a heat source, and the third heating device (130) can generate a smaller flow of the washing solvent inside the reactor by using the condensate, which is mostly condensed steam, as a heat source. Through this, there is an advantage in that an internal behavior can be realized in which a mixing flow in the up, down, left, and right directions is formed inside the reactor, thereby more efficiently and quickly melting the polymer (P) fouled inside the reactor.

[0081] In addition, when a third heating device (130) is further provided, the third reflux inlet may be located at a relatively lower height than the second reflux inlet, and the first reflux inlet may be located at a height between the second reflux inlet and the third reflux inlet.

[0082] For example, when the lowest part of the reactor (100) is 0% and the highest part is 100%, the first reflux inlet may be located at a height of 20% or more, 22% or more, or 24% or more, and 26% or less, 28% or less, or 30% or less of the total height of the reactor (100), the second reflux inlet may be located at a height of 50% or more, 52% or more, 54% or more, or 56% or more, and 64% or less, 66% or less, 68% or less, or 70% or less of the total height of the reactor (100), and the third reflux inlet may be located at a height of 10% or more, 12% or more, or 14% or more, and 16% or less, 18% or less, or 20% or less of the total height of the reactor (100).

[0083] When two or more of the above-mentioned one or more heating devices are provided, in the case of the second heating device (120) having the reflux inlet positioned at the highest point among the plurality of heating devices, a large swirl can be formed in the washing solvent (CS) in the reactor by utilizing a large amount of circulation flow using the high water pressure of the washing solvent stream that has passed through the second heating circulation line (L22). Furthermore, when a third heating device (130) is further provided, the high-temperature condensate used in the second heating device (120) can be input as a heat source of the third heating device (130) to perform heat exchange, and the washing solvent stream that has passed through the third heating circulation line (L23) can form a small swirl while being refluxed through the third reflux inlet. In this way, it is expected that the washing solvent inside the reactor will be mixed in the up, down, left, and right directions by the reflux inlets of the multiple heating devices each equipped at different heights, and as a result, the washing power for the fouled polymer (P) can be further improved.

[0084] Meanwhile, while heating the washing solvent (CS) in the reactor (100), the preheated washing solvent (CS) in the washing solvent supply unit (200) can be circulated through an auxiliary circulation line (L12) connecting the washing solvent supply line (L13) and the washing solvent discharge line (L14). More specifically, one side of the auxiliary circulation line (L12) can be connected between the second valve (302) of the washing solvent supply line (L13) and the washing solvent supply unit (200), and the other side can be connected between the third valve (303) of the washing solvent discharge line (L14) and the washing solvent supply unit (200).

[0085] In addition, the auxiliary circulation line (L12) may be provided with a fourth valve (304). Specifically, as shown in FIGS. 3a, 3c, 4a, and 4c, the fourth valve (304) may be closed when the second and third valves (302, 303) are opened, and as shown in FIGS. 3b and 4b, the fourth valve (304) may be opened when the second and third valves (302, 303) are closed. In this way, when the valves (301, 304) of the preheating circulation line (L11) and the auxiliary circulation line (L12) are opened and both circulation lines are operated simultaneously while the second and third valves (302, 303) are blocked to isolate the reactor and heat the internal washing solvent (CS), there is an advantage in that the rear stage pipe through which the washing solvent stream is discharged from the reactor and transferred, i.e., the washing solvent discharge line (L14), is sufficiently heated during that time, thereby preventing plugging from occurring when the washing solvent (CS) in which the polymer (P) is melted passes through the washing solvent discharge line (L14).

[0086] According to one embodiment of the present invention, as shown in FIGS. 3c and 4c, the washing solvent (CS) is additionally supplied from the washing solvent supply unit (200) to the reactor (100) through the washing solvent supply line (L13) to fill the interior of the reactor (100), and a washing solvent stream containing a polymer can be transferred to the washing solvent supply unit (200) through the washing solvent discharge line (L14) connected to the upper portion of the reactor (100).

[0087] Specifically, the reactor (100) is filled with a washing solvent (CS), and then a washing solvent stream is continuously supplied to the reactor (100) to circulate the high-temperature washing solvent stream between the washing solvent supply unit (200) and the reactor (100). At this time, a plurality of heating devices provided outside the reactor may be continuously operated, and further, the internal temperature of the reactor (100) may be maintained at 140° C. or higher or 145° C. or higher and 155° C. or lower or 160° C. When the washing solvent stream is circulated, by controlling the internal temperature of the reactor (100) within the above range, the polymer (P) accumulated on the inner wall of the reactor (100) can be melted in the washing solvent and removed. Furthermore, due to the operation of the plurality of heating devices, a turbulent flow effect and heat loss inside the reactor can be prevented, so that the polymer fouled on the inner wall of the reactor can be more effectively removed.

[0088] In addition, the temperature of the washing solvent stream discharged to the upper part of the reactor (100) may be 140°C or higher or 145°C or higher, and 155°C or lower or 160°C or lower. Since the fouled polymer (P) is melted in the washing solvent stream discharged to the upper part of the reactor (100), the temperature of the washing solvent stream must be maintained at a sufficiently high temperature during discharge and circulation to prevent plugging in the washing solvent discharge line (L14). Accordingly, by satisfying the temperature range of the washing solvent stream, clogging of the pipe by the polymer (P) during circulation of the washing solvent stream can be prevented.

[0089] The time for which the washing solvent stream is discharged from the reactor (100) and circulated may be 12 hours or more, 14 hours or more, or 16 hours or more, and 20 hours or less, 22 hours or less, or 24 hours or less. In addition, the flow rate for which the washing solvent stream is discharged from the reactor (100) and circulated may be 100 kg / hr or more, 150 kg / hr or more, or 200 kg / hr or more, and 300 kg / hr or less, 400 kg / hr or less, or 500 kg / hr or less. By satisfying the above conditions during the circulation of the washing solvent stream, the washing rate of the polymer (P) accumulated in the reactor (100) can be improved.

[0090] By cleaning the reactor using the method of the present invention, the possibility of plugging in the cleaning solvent delivery pipe that may occur during the cleaning process can be reliably eliminated, and fouled polymers (P) within the reactor can be completely removed in a short period of time with significantly higher cleaning efficiency compared to conventional cleaning methods. Ultimately, normal process operation can be resumed after a quick cleaning, thereby improving economic efficiency.

[0091] Above, the reactor cleaning method and system according to the present invention have 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 invention, 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 reactor cleaning method and system according to the present invention.

[0092] Additionally, a person of ordinary skill in the art will understand that various changes and modifications are possible within the scope and concept of the claims described below.

[0093] [Explanation of symbols]

[0094] 100: Reactor

[0095] 110, 120, 130: Heating device

[0096] 111, 121, 131: Heat source of heating device

[0097] 112, 122, 132: Condensate from the heating device

[0098] 200: Washing solvent supply, 210: Washing solvent storage tank, 220: Pump, 230: Heater

[0099] 301, 302, 303, 304: Valves

[0100] L10: Lower discharge line of the washing solvent storage tank

[0101] L11: Preheating circulation line, L12: Auxiliary circulation line

[0102] L13: Washing solvent supply line, L14: Washing solvent discharge line

[0103] L21, L22, L23: Heating circulation line

[0104] CS: washing solvent, P: fouled polymer

Claims

1. A step of supplying a washing solvent from a washing solvent supply unit to a reactor through a washing solvent supply line to partially fill the interior of the reactor; A step of heating the washing solvent in the reactor; and A step of additionally supplying a washing solvent from the washing solvent supply unit to the reactor through the washing solvent supply line to fill the interior of the reactor, and transferring a washing solvent stream containing a polymer to the washing solvent supply unit through a washing solvent discharge line connected to the upper part of the reactor; The step of heating the washing solvent in the above reactor is: A method for cleaning a reactor, comprising feeding a bottom discharge stream of the reactor to one or more heating devices and then refluxing the stream to a side of the reactor.

2. In paragraph 1, The step of heating the washing solvent in the above reactor is: A method for cleaning a reactor, comprising: supplying a first bottom discharge stream of the reactor to a first heater and then refluxing it to a first reflux inlet located at one side of the reactor; and supplying a second bottom discharge stream of the reactor to a second heater and then refluxing it to a second reflux inlet located at the other side of the reactor.

3. In paragraph 2, A method for cleaning a reactor, wherein the first heating device has a length 1.5 to 2 times longer than the second heating device.

4. In paragraph 2, The step of heating the washing solvent in the above reactor is: A method for washing a reactor further comprising: supplying a portion of a second bottom discharge stream of the reactor to a second heater and then refluxing it to a second reflux inlet located on the other side of the reactor, and supplying the remaining stream to a third heater and then refluxing it to a third reflux inlet located on the other side of the reactor.

5. In paragraph 1, A method for washing a reactor, wherein when the at least one heating device is two or more, the washing solvent stream refluxed from each heating device to the side of the reactor is refluxed at different heights.

6. In paragraph 4, A method for washing a reactor, wherein the first reflux inlet is located at a height between the second reflux inlet and the third reflux inlet, and the second reflux inlet is located relatively higher than the third reflux inlet.

7. In paragraph 1, A reactor washing method further comprising preheating the washing solvent in the washing solvent supply unit to a temperature range of 140° C. to 170° C.

8. In paragraph 1, A reactor washing method further comprising: while heating the washing solvent in the reactor, circulating the preheated washing solvent in the washing solvent supply unit through an auxiliary circulation line connecting the washing solvent supply line and the washing solvent circulation line.

9. In paragraph 1, A method for washing a reactor, wherein the washing solvent supplied to the reactor from the washing solvent supply unit is supplied to at least one of the lower part and the side of the reactor.

10. In paragraph 1, A method for cleaning a reactor, wherein the internal temperature of the reactor is maintained at 140°C to 160°C.

11. In paragraph 1, A method for washing a reactor, wherein the temperature of the washing solvent stream discharged from the upper portion of the reactor is 140°C to 160°C.

12. In paragraph 1, A method for washing a reactor, wherein the washing solvent comprises at least one selected from the group consisting of n-pentane, n-hexane, n-heptane, n-decane, cyclohexane, methyl cyclohexane, benzene, xylene, toluene, ethylbenzene, chlorobenzene, dichlorobenzene, and trichlorobenzene.

13. A washing solvent supply unit that supplies washing solvent from the outside, stores it, and preheats it, and is connected to at least one of the lower and side parts of the reactor through a washing solvent supply line to supply the washing solvent, and is connected to the upper part of the reactor through a washing solvent discharge line to recover the washing solvent discharged from the reactor; and A first heating device connected to one side of the reactor through a first heating circulation line and using steam as a heat source to heat the washing solvent in the reactor; A reactor washing system, wherein an auxiliary circulation line is provided for connecting the washing solvent supply line and the washing solvent discharge line, one side of the auxiliary circulation line is connected between a valve provided in the washing solvent supply line and the washing solvent supply unit, and the other side of the auxiliary circulation line is connected between a valve provided in the washing solvent discharge line and the washing solvent supply unit.

14. In paragraph 13, It further includes a second heating device connected to the other side of the reactor through a second heating circulation line and heating the washing solvent in the reactor using steam as a heat source; A reactor cleaning system, characterized in that the length of the first heating device is 1.5 to 2 times the length of the second heating device, and the reflux inlet of the first heating device is located at a lower height than the reflux inlet of the second heating device.

15. In paragraph 14, A reactor washing system further comprising a third heating device connected to the other side of the reactor through a third heating circulation line, the third heating device using the condensate condensed from the heat source of the second heating device as a heat source to heat the washing solvent inside the reactor.

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