Reactor cleaning method

Abstract

The present invention relates to a reactor cleaning method. The method includes pressurizing a cleaning solvent vessel to 5 kg / cm 2 .g to 40 kg / cm 2 .g using a pressurized gas; supplying a cleaning solvent stream from the cleaning solvent vessel to one or more of a lower portion and a side portion of a reactor to fill an interior of the reactor; and circulating the cleaning solvent stream between the cleaning solvent vessel and the reactor while maintaining a temperature of the reactor at 115°C to 200°C.

Description

Technical Field

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2021-0133998, filed on October 8, 2021, and Korean Patent Application No. 10-2022-0081252, filed on July 1, 2022, the entire contents of which are incorporated herein by reference as a part of the specification. Technical Field

[0004] This invention relates to a reactor cleaning method, and more specifically, to a reactor cleaning method for ethylene oligomerization. Background Technology

[0005] Alpha-olefins are widely used commercially as important materials in comonomers, cleaning agents, lubricants, plasticizers, etc. In particular, 1-hexene and 1-octene have been widely used as comonomers to control the density of polyethylene in the production of linear low-density polyethylene (LLDPE).

[0006] α-Olefins such as 1-hexene and 1-octene are typically prepared via the oligomerization of ethylene. The oligomerization of ethylene is carried out in the presence of a catalyst using ethylene as a reactant via an oligomerization reaction (trimerization or tetramerization). The reaction product is a multi-component hydrocarbon mixture containing the desired 1-hexene and 1-octene, as well as a small amount of polymer generated as a byproduct during the catalytic reaction. This polymer is suspended in the liquid reaction medium within the reactor, and over time, due to scaling, it accumulates to a certain thickness within the reactor. Therefore, reactor operation should be stopped, and the reactor and reactor auxiliary equipment should be cleaned. Summary of the Invention

[0007] [Technical Issues]

[0008] This invention provides a method for improving the cleaning efficiency when cleaning polymers accumulated in an ethylene oligomerization reactor.

[0009] [Technical Solution]

[0010] In one general aspect, a reactor cleaning method includes: pressurizing a cleaning solvent container to 5 kg / cm² using pressurized gas. 2 .g to 40kg / cm 2 g; supplying a cleaning solvent stream from the cleaning solvent container to one or more of the lower and side portions of the reactor to fill the interior of the reactor; and circulating the cleaning solvent stream between the cleaning solvent container and the reactor while maintaining the temperature of the reactor at 115°C to 200°C.

[0011] [Beneficial Effects]

[0012] According to the reactor cleaning method of the present invention, the reactor cleaning rate can be improved by controlling the operating conditions of the cleaning solvent container and the reactor and by improving the cleaning method so as to remove the polymer accumulated in the reactor by circulating the cleaning solvent stream between the cleaning solvent container and the reactor. Attached Figure Description

[0013] Figures 1 to 3 These are process flow diagrams of the reactor cleaning method according to embodiments of the present invention.

[0014] Figure 4 and Figure 5 These are process flow diagrams for the reactor cleaning method based on the comparative example. Detailed Implementation

[0015] The terms and words used in this specification and claims should not be interpreted in their general or dictionary sense, but rather based on the principle that the inventors are able to properly define the concepts of the terms in order to best describe their own invention, and should be interpreted as meanings and concepts consistent with the technical ideas of the invention.

[0016] In this invention, the term "stream" can refer to the flow of fluid in a process, or to the fluid itself flowing in a moving pipeline (pipeline). Specifically, "stream" can refer to the fluid itself, or to the flow of fluid within the pipes connecting each device. Furthermore, the fluid can include any one or more components of gas, liquid, and solid.

[0017] The following will refer to Figures 1 to 3 The invention will be described in more detail to aid in understanding it.

[0018] According to the present invention, a reactor cleaning method is provided. The reactor cleaning method includes: pressurizing a cleaning solvent container to 5 kg / cm² using pressurized gas. 2 .g to 40kg / cm 2 g; supplying a cleaning solvent stream from the cleaning solvent container to one or more of the lower and side portions of the reactor 10 to fill the interior of the reactor 10; and circulating the cleaning solvent stream between the cleaning solvent container and the reactor 10 while maintaining the temperature of the reactor 10 at 115°C to 200°C.

[0019] According to one embodiment of the present invention, reactor 10 may be an oligomerization reactor for ethylene. α-olefins are widely used commercially as important materials for comonomers, cleaning agents, lubricants, plasticizers, etc. In particular, 1-hexene and 1-octene have been widely used as comonomers to control the density of polyethylene in the production of linear low-density polyethylene (LLDPE), and α-olefins can be prepared by the oligomerization reaction of ethylene.

[0020] The oligomerization of ethylene can be carried out by trimerization or tetramerization of ethylene using ethylene as a reactant in the presence of a catalyst and a co-catalyst.

[0021] Oligopolymerization can refer to the reaction in which monomers oligomerize. Depending on the number of monomers to be polymerized, it is called trimer and tetramer, and these trimers and tetramers are collectively referred to as polymers.

[0022] Catalysts used for the oligomerization of ethylene may include a transition metal supply source. The transition metal supply source may be one or more compounds selected from, for example, chromium acetylacetonate (III), chromium tetrahydrofuran chloride (III), chromium 2-ethylhexanoate (III), tris(2,2,6,6-tetramethyl-3,5-heptadecanoate)chromium (III), chromium benzoylpyruvate (III), chromium hexafluoro-2,4-pentanedione (III), chromium acetate (III) hydroxide, chromium acetate (III), chromium butyrate (III), chromium valerate (III), chromium laurate (III), and chromium stearate (III).

[0023] The cocatalyst may include one or more selected from, for example, trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, ethyl sesquichloride, diethylaluminum chloride, ethyl dialuminum chloride, methylaluminoxane, modified methylaluminoxane, and borate.

[0024] Therefore, during the oligomerization of ethylene monomers in the presence of a catalyst, in addition to the oligomer products, polymers such as polyethylene can also be generated as byproducts during the catalytic reaction. This polymer is suspended in the liquid reaction medium within the reactor, leading to a problem where, over time, due to scaling, the polymer accumulates to a certain thickness within the reactor. In this case, it is necessary to shut down the reactor and clean the reactor and its auxiliary equipment.

[0025] Traditionally, cleaning reactors scaled by polymers involves disassembling the reactor and other equipment, cleaning them for extended periods, and then reinstalling them. This results in reduced production, increased cleaning costs, and deteriorated reaction stability due to the increased reaction normalization time after cleaning when the plant is shut down.

[0026] On the other hand, the present invention provides a reactor cleaning method that can clean reactors and auxiliary devices scaled by polymers in a short time by circulating the cleaning solvent between the cleaning solvent container storing the cleaning solvent and the reactor, and by simultaneously optimizing the operating conditions and cleaning methods to improve the cleaning rate. Furthermore, it can increase production, reduce cleaning costs, and improve reaction stability by reducing downtime.

[0027] According to one embodiment of the present invention, a cleaning solvent can be used to clean the reactor 10. For example, the cleaning solvent may include one or more selected from n-pentane, n-hexane, n-heptane, n-decane, cyclohexane, methylcyclohexane, benzene, xylene, toluene, ethylbenzene, chlorobenzene, dichlorobenzene, and trichlorobenzene. As a specific example, the cleaning solvent may be methylcyclohexane, toluene, or n-decane.

[0028] The cleaning solvent can be input through the cleaning solvent supply line 21 of the cleaning solvent container 20, and the cleaning solvent can be heated by operating the pump 30 and the heater 40. Specifically, the cleaning solvent supplied to the cleaning solvent container 20 is discharged through the lower discharge line L10 of the cleaning solvent container, and can be heated by circulating through a heating circulation line L11 that branches off from the lower discharge line and connects to the cleaning solvent container 20. For example, the cleaning solvent stream is discharged through the heating circulation line L11, the cleaning solvent stream is circulated back to the cleaning solvent container 20 using the pump 30, the cleaning solvent can be heated to the desired temperature using the heater 40 provided in the heating circulation line L11, and the temperature of the heated cleaning solvent can be maintained.

[0029] The heating circulation line L11 may further include a first valve 50. The first valve 50 can be opened when heating the cleaning solvent flow and can be closed when cleaning the reactor 10.

[0030] The temperature of the heating cleaning solvent flow during circulation in the heating circulation line L11 can be above 140°C, above 150°C, or above 160°C, and below 180°C, below 190°C, or below 200°C. When the cleaning solvent is heated within the above range and then used to clean the reactor 10, the scale polymers swell sufficiently, and can therefore be easily removed by circulating the cleaning solvent.

[0031] According to one embodiment of the present invention, the cleaning solvent container 20 can be pressurized using pressurized gas supplied via pressurized gas supply line 22. For example, the pressurized gas may include one or more selected from nitrogen and ethylene. As a specific example, the pressurized gas may be nitrogen or ethylene gas.

[0032] When using pressurized gas to clean the solvent container 20, the pressure is less than 5 kg / cm². 2At times like this, because the pressure in the cleaning solvent container becomes similar to the vapor pressure of the cleaning solvent, some of the cleaning solvent may evaporate, potentially leading to solvent loss. As a result, there is a reduction in cleaning effectiveness, and economic viability deteriorates due to the increased downtime required to replenish the depleted cleaning solvent.

[0033] Meanwhile, when the pressure in the cleaning solvent container 20 exceeds 40 kg / cm² 2 At .g., there may be economic feasibility issues (excessive equipment costs) and stability problems in handling pressurized gases due to high pressure conditions.

[0034] Considering the above, by using pressurized gas, the cleaning solvent container 20 can be pressurized to 5 kg / cm². 2 .g to 40kg / cm 2 Within the range of .g, especially 7kg / cm 2 .g to 30kg / cm 2 g. By pressurizing the cleaning solvent container within the above range, evaporation can be suppressed by operating within the vapor pressure of the solvent, and the cleaning capacity can be improved by increasing the solubility of ethylene in the solvent.

[0035] According to one embodiment of the invention, the method may include supplying a cleaning solvent stream from a cleaning solvent container 20 to any one or more of the lower and side portions of a reactor 10 to fill the interior of the reactor 10. Specifically, the heated cleaning solvent stream may be discharged through a lower discharge line of the cleaning solvent container 20 pressurized by pressurized gas and supplied to the reactor 10.

[0036] The lower discharge line L10 of the cleaning solvent container can branch into the aforementioned heating circulation line L11 and cleaning circulation line L12. The heated cleaning solvent stream discharged after pressurizing the cleaning solvent container 20 with pressurized gas can be supplied to the reactor 10 via the cleaning circulation line L12. In this case, the cleaning circulation line L12 can be collectively referred to as the line connecting the lower discharge line L10 of the cleaning solvent container to the reactor 10, and the line connecting the upper discharge line of the reactor 10 to the cleaning solvent container 20.

[0037] A second valve 51 can be further installed in the cleaning circulation line L12 adjacent to the lower discharge line L10 of the cleaning solvent container. The second valve 51 can be closed when the cleaning solvent flow is heated and can be opened when cleaning the reactor 10.

[0038] The cleaning solvent stream discharged from the cleaning solvent container 20 can be supplied to the lower part of the reactor 10, to the side of the reactor, or simultaneously to both the lower and side of the reactor. In this case, when the lower end of the reactor 10 is 1% and the upper end of the reactor is 100%, the lower part of the reactor 10 can refer to the lower end of the reactor 10, while the side of the reactor 10 can refer to 5% or more, 6% or more, 7% or more, 8% or more, 9% or more, and less than 10%, less than 11%, less than 13%, less than 15%, or less than 20% of the total height of the reactor 10. When the cleaning solvent is supplied to the side of the reactor 10 within the above range, the cleaning ability of polymers accumulated on the surface of the reactor 10 wall and on auxiliary equipment such as sensors can be improved.

[0039] Specifically, even when the cleaning solvent stream discharged from the cleaning solvent container 20 is supplied to the lower and side parts of the reactor 10 respectively, the cleaning of the reactor 10 can be carried out smoothly. Furthermore, when the cleaning solvent stream is supplied to the lower and side parts of the reaction vessel 10 simultaneously, the flow direction of the cleaning solvent in the reactor 10 can be continuously changed to improve the cleaning ability of auxiliary devices such as sensors installed in the reactor 10 and the polymers accumulated on the lower and wall surfaces of the reactor 10.

[0040] According to one embodiment of the invention, the method may include filling reactor 10 with a cleaning solvent and then circulating the cleaning solvent stream between cleaning solvent container 20 and reactor 10. In this case, the temperature of reactor 10 may be maintained above 115°C, above 120°C, above 130°C, above 140°C, above 150°C, above 160°C and below 180°C, below 190°C, or below 200°C. When the cleaning solvent stream is circulated, by controlling the temperature of reactor 10 within the above-mentioned range, the polymer accumulated in reactor 10 can be sufficiently swollen for removal.

[0041] In the step of circulating the cleaning solvent stream, the circulation time can be 12 hours or longer, 15 hours or longer, 20 hours or longer and 24 hours or less, 26 hours or less, or 28 hours or less. Furthermore, in the step of circulating the cleaning solvent stream, the circulation flow rate can be 50 kg / hr or more, 80 kg / hr or more, 100 kg / hr or more and 300 kg / hr or less, 350 kg / hr or less, or 400 kg / hr or less. When the cleaning solvent stream is circulated, the cleaning rate of the polymer accumulated in reactor 10 can be increased by meeting the above conditions.

[0042] According to embodiments of the present invention, methylcyclohexane can be used as a cleaning solvent, and nitrogen or ethylene gas can be used as a pressurizing gas. Specifically, when methylcyclohexane is used as a cleaning solvent for circulating reactor 10 and cleaning solvent container 20, nitrogen or ethylene gas can be used as a pressurizing gas for pressurizing cleaning solvent container 20.

[0043] In this case, considering that the vapor pressure of methylcyclohexane in the temperature range of 140°C to 200°C is approximately 3.1 kg / cm², 2 .g. The cleaning solvent container 20 can be pressurized to 5 kg / cm² by using nitrogen or ethylene gas as the pressurizing gas. 2 .g to 40kg / cm 2 .g, specifically, pressurized to 7 kg / cm² 2 .g to 30kg / cm 2 For example, when cleaning solvent containers 20 are pressurized to below 5 kg / cm². 2 At pressures above 0.05 g, the loss of methylcyclohexane increases due to evaporation and loss along with the pressurized gas, thus reducing cleaning efficiency. Furthermore, in order to maintain the cleaning solvent container 20 above 40 kg / cm³, [further measures are needed]. 2 Under pressure of .g, economic efficiency will decrease (excessive equipment costs), and stability issues may arise when handling pressurized gases.

[0044] Furthermore, when methylcyclohexane is used as the cleaning solvent and nitrogen or ethylene gas is used as the pressurizing gas, the temperature of reactor 10 during the circulation of the cleaning solvent stream is above 130°C, above 140°C, above 150°C, or above 160°C and below 180°C, or below 190°C.

[0045] Furthermore, when methylcyclohexane is used as the cleaning solvent and nitrogen is used as the pressurizing gas, the pressure of the cleaning solvent container 20 pressurized by the pressurizing gas can be 5 kg / cm². 2 .g or above or 6kg / cm 2 .g or more and 8kg / cm 2 Below .g, 9kg / cm 2 Below .g, or 10kg / cm 2 Below .g. Furthermore, when using methylcyclohexane as the cleaning solvent and ethylene gas as the pressurizing gas, the pressure of the cleaning solvent container 20 pressurized by the pressurizing gas can be 7 kg / cm². 2 .g or more, 10kg / cm 2 .g or more, 20kg / cm 2 .g or above, or 25kg / cm 2 .g or more, and 30kg / cm2 Below .g, or 40kg / cm 2 Below .g.

[0046] As described above, by controlling the type of cleaning solvent, the type of pressurized gas, the degree of pressurization, the temperature of reactor 10, etc., the cleaning rate can be improved by satisfying the optimal conditions for cleaning the polymer accumulated in reactor 10.

[0047] According to embodiments of the present invention, toluene or n-decane can be used as the cleaning solvent, and nitrogen can be used as the pressurizing gas. Specifically, when toluene or n-decane is used as the cleaning solvent for circulating the reactor 10 and the cleaning solvent container 20, nitrogen can be used as the pressurizing gas for pressurizing the cleaning solvent container 20.

[0048] Furthermore, when toluene or n-decane is used as the cleaning solvent and nitrogen is used as the pressurizing gas, the temperature of reactor 10 during the circulation of the cleaning solvent stream is above 140°C or above 150°C and below 170°C or below 180°C.

[0049] Furthermore, when toluene or n-decane is used as the cleaning solvent and nitrogen is used as the pressurizing gas, the pressure of the cleaning solvent container 20 pressurized by the pressurizing gas can be 5 kg / cm². 2 .g or above, or 6kg / cm 2 .g or more, and 8kg / cm 2 Below .g, 9kg / cm 2 Below g, or 10 kg / cm 2 Below .g.

[0050] As described above, by controlling the type of cleaning solvent, the type of pressurized gas, the degree of pressurization, the temperature of reactor 10, etc., the cleaning rate can be improved by satisfying the optimal conditions for cleaning the polymer accumulated in reactor 10.

[0051] The reactor cleaning method according to the present invention has been illustrated above in the specification and accompanying drawings, but the drawings and specification only describe and illustrate the basic components for understanding the invention. In addition to the methods and apparatus shown in the specification and accompanying drawings, methods and apparatus not separately described and shown may be suitably applied and used to implement the reactor cleaning method according to the present invention.

[0052] The present invention will now be described in more detail through embodiments. However, the following embodiments are for illustrative purposes only, and those skilled in the art will understand that various changes and modifications can be made within the scope and spirit of the present invention, and that the scope of the present invention is not limited thereto.

[0053] Example

[0054] Example 1

[0055] According to the following Figure 1 The process flow diagram shown is for cleaning reactor 10.

[0056] Specifically, the oligomerization reaction of ethylene is carried out in reactor 10. After the reaction is completed, the reaction solution is transferred to a storage container, and the polymer adhering to the reactor is washed away. In this case, the pre-cleaning step is performed in the same manner as in Examples 2 to 9 and Comparative Examples 1 to 4.

[0057] 350 kg of methylcyclohexane, used as a cleaning solvent, is introduced through the cleaning solvent supply line 21 of the cleaning solvent container 20. It is heated simultaneously by circulating it through the heating circulation line L11 using pump 30 and heater 40, and maintained at 170°C. Furthermore, nitrogen gas, used as a pressurized gas, is introduced through the pressurized gas supply line 22 of the cleaning solvent container 20, and the cleaning solvent container 20 is pressurized to 7 kg / cm³. 2 .g.

[0058] Then, after the cleaning solvent is discharged into the lower discharge line L10 of the cleaning solvent container, fed into the lower part of the reactor 10 and filled to the upper end of the reactor, the temperature of the reactor 10 is maintained at 160°C, and the cleaning solvent is circulated through the cleaning circulation line L12 for 24 hours, while the flow rate of the cleaning solvent is controlled at 100 kg / hr to 200 kg / hr.

[0059] Subsequently, the cleaning solvent collected in the cleaning solvent container 20 was sampled and filtered, and after vacuum drying, the weight of the polymer was measured. This was carried out under the same conditions as in Examples 2 to 9 and Comparative Examples 1 to 4, and the polymer cleaning rate was confirmed to be 60.54%, based on the polymer weight conversion of Example 7, in which the polymer weight measurement was the highest.

[0060] Example 2

[0061] According to the following Figure 2 The process flow diagram shown is for cleaning reactor 10.

[0062] 350 kg of methylcyclohexane, used as a cleaning solvent, is introduced through the cleaning solvent supply line 21 of the cleaning solvent container 20. It is heated while being circulated through the heating circulation line L11 using pump 30 and heater 40, and maintained at 170°C. Furthermore, nitrogen gas, used as a pressurized gas, is introduced through the pressurized gas supply line 22 of the cleaning solvent container 20, and the cleaning solvent container 20 is pressurized to 7 kg / cm³. 2 .g.

[0063] Then, after the cleaning solvent is discharged into the lower discharge line L10 of the cleaning solvent container, enters the reactor 10 at a position of 10% of the total height, and fills the upper end of the reactor 10, the temperature of the reactor 10 is maintained at 160°C, and the cleaning solvent is circulated through the cleaning circulation line L12 for 24 hours, while the flow rate of the cleaning solvent is controlled at 200 kg / hr.

[0064] Subsequently, the cleaning solvent collected in the cleaning solvent container 20 was sampled and filtered, and then vacuum dried. The weight of the polymer was measured, and the polymer cleaning rate was confirmed to be 66.49%, based on the polymer weight measured in Example 7 below as 100% conversion.

[0065] Example 3

[0066] According to the following Figure 3 The process flow diagram shown is for cleaning reactor 10.

[0067] 350 kg of methylcyclohexane, used as a cleaning solvent, is introduced through the cleaning solvent supply line 21 of the cleaning solvent container 20. It is heated simultaneously by circulating it through the heating circulation line L11 using pump 30 and heater 40, and maintained at 170°C. Furthermore, nitrogen gas, used as a pressurized gas, is introduced through the pressurized gas supply line 22 of the cleaning solvent container 20, and the cleaning solvent container 20 is pressurized to 7 kg / cm³. 2 .g.

[0068] Then, the cleaning solvent is discharged into the lower discharge line L10 of the cleaning solvent container, and simultaneously fed into the lower part of the reactor 10 and the position of 10% of the total height of the reactor 10, and filled to the upper end of the reactor 10. The temperature of the reactor 10 is maintained at 130°C, and the cleaning solvent is circulated through the cleaning circulation line L12 for 24 hours, while the flow rate of the cleaning solvent is controlled at 200 kg / hr.

[0069] Subsequently, the cleaning solvent collected in the cleaning solvent container 20 was sampled and filtered, and after vacuum drying, the weight of the polymer was measured, and the polymer cleaning rate was confirmed to be 87.03%, based on the polymer weight measured in Example 7 below as 100% conversion.

[0070] Example 4

[0071] Except that in Example 3 above, the cleaning solvent stream was filled to the top of the reactor 10 and the temperature of the reactor 10 was maintained at 160°C, Example 4 was carried out in the same manner as in Example 3 above.

[0072] Subsequently, the cleaning solvent collected in the cleaning solvent container 20 was sampled and filtered, and after vacuum drying, the weight of the polymer was measured, and the polymer cleaning rate was confirmed to be 94.05%, based on the polymer weight measured in Example 7 below as 100% conversion.

[0073] Example 5

[0074] Except that in Example 3 above, the cleaning solvent stream was filled to the top of the reactor 10 and the temperature of the reactor 10 was maintained at 180°C, Example 5 was carried out in the same manner as in Example 3 above.

[0075] Subsequently, the cleaning solvent collected in the cleaning solvent container 20 was sampled and filtered, and after vacuum drying, the weight of the polymer was measured, and the polymer cleaning rate was confirmed to be 97.30%, based on the polymer weight measured in Example 7 below as 100% conversion.

[0076] Example 6

[0077] Example 6 was carried out in the same manner as Example 4, except that ethylene gas was used instead of nitrogen gas as the pressurizing gas in Example 4.

[0078] Subsequently, the cleaning solvent collected in the cleaning solvent container 20 was sampled and filtered, and after vacuum drying, the weight of the polymer was measured, and the polymer cleaning rate was confirmed to be 97.84%, based on the polymer weight measured in Example 7 below as 100% conversion.

[0079] Example 7

[0080] In addition to inputting pressurized gas in Example 6 above to pressurize the cleaning solvent container 20 to 30 kg / cm³, 2 Except for .g, Example 7 is carried out in the same manner as Example 6 described above.

[0081] Subsequently, the cleaning solvent collected in the cleaning solvent container 20 was sampled and filtered, and after vacuum drying, the weight of the polymer was measured, and it was confirmed that the measured weight of the polymer was 1.85 kg, which was the highest, and was set as 100%.

[0082] Example 8

[0083] Example 8 was carried out in the same manner as Example 4, except that toluene was used instead of methylcyclohexane as the cleaning solvent in Example 4 above.

[0084] Subsequently, the cleaning solvent collected in the cleaning solvent container 20 was sampled and filtered, and then vacuum dried. The weight of the polymer was measured, and the polymer cleaning rate was confirmed to be 97.84%, which was converted based on the polymer weight measured in Example 7 above as 100%.

[0085] Example 9

[0086] Example 9 was carried out in the same manner as Example 4, except that n-decane was used instead of methylcyclohexane as the cleaning solvent in Example 4 above.

[0087] Subsequently, the cleaning solvent collected in the cleaning solvent container 20 was sampled and filtered, and then vacuum dried. The weight of the polymer was measured, and the polymer cleaning rate was confirmed to be 98.92%, which was converted based on the polymer weight measured in Example 7 above as 100%.

[0088] Comparative example

[0089] Comparative Example 1

[0090] According to the following Figure 4 The process flow diagram shown is for cleaning reactor 10.

[0091] 350 kg of methylcyclohexane as a cleaning solvent is input through the cleaning solvent supply line 21 of the cleaning solvent container 20, and heated while being circulated through the heating circulation line L11 using the pump 30 and heater 40, and maintained at 170°C.

[0092] Then, after the cleaning solvent is discharged into the lower discharge line L10 of the cleaning solvent container, fed into the lower part of reactor 10, and filled to the upper end of reactor 10, the temperature of reactor 10 is maintained at 100°C. The cleaning solvent is circulated through the cleaning circulation line L12 for 24 hours, while the flow rate of the cleaning solvent is controlled at 200 kg / hr. Under these conditions, the vapor pressure of methylcyclohexane is confirmed to be 0 kg / cm³. 2 .g.

[0093] Subsequently, the cleaning solvent collected in the cleaning solvent container 20 was sampled and filtered, and then vacuum dried. The weight of the polymer was measured, and the polymer cleaning rate was confirmed to be 16.76%, which was converted based on the polymer weight measured in Example 7 above as 100%.

[0094] Comparative Example 2

[0095] Comparative Example 2 was performed in the same manner as in Example 3, except that the cleaning solvent stream was filled to the top of the reactor 10 and the temperature of the reactor 10 was maintained at 100°C.

[0096] Subsequently, the cleaning solvent collected in the cleaning solvent container 20 was sampled and filtered, and then vacuum dried. The weight of the polymer was measured, and the polymer cleaning rate was confirmed to be 22.70%, which was converted based on the polymer weight measured in Example 7 above as 100%.

[0097] Comparative Example 3

[0098] According to the following Figure 4 The process flow diagram shown is for cleaning reactor 10.

[0099] 350 kg of methylcyclohexane as a cleaning solvent is input through the cleaning solvent supply line 21 of the cleaning solvent container 20, and heated while being circulated through the heating circulation line L11 using the pump 30 and heater 40, and maintained at 170°C.

[0100] Then, after the cleaning solvent is discharged into the lower discharge line L10 of the cleaning solvent container, fed into the lower part of reactor 10, and filled to the upper part of reactor 10, the temperature of reactor 10 is maintained at 160°C. The cleaning solvent is circulated through the cleaning circulation line L12 for 24 hours, while the flow rate of the cleaning solvent is controlled at 200 kg / hr. Under these conditions, the vapor pressure of methylcyclohexane is confirmed to be 3.1 kg / cm³. 2 .g.

[0101] Subsequently, the cleaning solvent collected in the cleaning solvent container 20 was sampled and filtered, and then vacuum dried. The weight of the polymer was measured, and the polymer cleaning rate was confirmed to be 34.05%, which was converted from the polymer weight measured in Example 7 above as 100%.

[0102] Comparative Example 4

[0103] According to the following Figure 5 The process flow diagram shown is for cleaning reactor 10.

[0104] 350 kg of methylcyclohexane, used as a cleaning solvent, is introduced through the cleaning solvent supply line 21 of the cleaning solvent container 20. It is heated simultaneously by circulating it through the heating circulation line L11 using pump 30 and heater 40, and maintained at 170°C. Furthermore, nitrogen gas, used as a pressurized gas, is introduced through the pressurized gas supply line 22 of the cleaning solvent container 20, and the cleaning solvent container 20 is pressurized to 7 kg / cm³. 2 .g.

[0105] Then, after the cleaning solvent is discharged into the lower discharge line L10 of the cleaning solvent container, and simultaneously fed into the lower part of the reactor 10 and the position of 10% of the total height of the reactor 10, and filled to the upper end of the reactor 10, the temperature of the reactor 10 is maintained at 160°C, and the cleaning solvent is stored in the reactor 10 for 24 hours.

[0106] Subsequently, the cleaning solvent in reactor 10 was sampled and filtered, and after vacuum drying, the weight of the polymer was measured, and the polymer cleaning rate was confirmed to be 50.81%, which was converted based on the polymer weight measured in Example 7 above as 100%.

Claims

1. A reactor cleaning method comprising: The cleaning solvent container is pressurized to 5 kg / cm 2 .g to 40 kg / cm 2 .g; simultaneously supplying a cleaning solvent stream from the cleaning solvent vessel to a lower portion and a side portion of the reactor to fill an interior of the reactor; and circulating the cleaning solvent stream between the cleaning solvent vessel and the reactor while maintaining a temperature of the reactor at 115°C to 200°C, wherein the lower portion of the reactor is a lower end of the reactor, and the side portion of the reactor is a location that is 5% to 20% of a total height of the reactor based on 100% of an upper end of the reactor, wherein the cleaning solvent stream is discharged through an upper portion discharge line of the reactor.

2. The method of claim 1, wherein the cleaning solvent comprises one or more selected from the group consisting of n-pentane, n-hexane, n-heptane, n-decane, cyclohexane, methylcyclohexane, benzene, xylene, toluene, ethylbenzene, chlorobenzene, dichlorobenzene, and trichlorobenzene.

3. The method of claim 1, wherein the pressurized gas comprises one or more selected from the group consisting of nitrogen and ethylene.

4. The method of claim 1, wherein the cleaning solvent is methylcyclohexane, and the pressurized gas is nitrogen or ethylene.

5. The method of claim 1, wherein the cleaning solvent is toluene or n-decane, and the pressurized gas is nitrogen.

6. The method of claim 1, wherein a temperature of the cleaning solvent added to the cleaning solvent vessel is heated to 140°C to 200°C.

8. The method of claim 1, wherein the temperature of the reactor is maintained at 130°C to 180°C.

7. The method according to claim 1, wherein the cleaning solvent container is pressurized to 7 kg / cm 2 .g to 30 kg / cm 2 .g using the pressurized gas.

7. The method according to claim 1, wherein the cleaning solvent container is pressurized to 7 kg / cm 2 .g to 30 kg / cm 2 .g using the pressurized gas.

9. The method of claim 1, wherein the reactor is an oligomerization reactor for ethylene. ​

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