Polymerizer backwashing device and polymerizer

Abstract

The application provides a polymerizer backwashing device, which comprises a nozzle arranged in the interior of a polymerizer and arranged below a sight glass, an explosion-proof plate and a pressure transmitter diaphragm respectively, the nozzle is connected with a first methanol conveying pipeline used for conveying methanol, one end of the first methanol conveying pipeline opposite to the nozzle is connected with a high-temperature methanol outlet of a heater, and a low-temperature methanol inlet of the heater is connected with a methanol conveying main pipeline through a first branch pipe. The application further provides a polymerizer comprising the backwashing device. According to the polymerizer backwashing device, the ethylene-vinyl acetate self-polymer on the surface of the sight glass, the explosion-proof plate and the pressure transmitter diaphragm can be quickly cleaned without stopping the polymerizer, and the normal operation of the polymerizer is ensured.

Description

Technical Field

[0001] This application pertains to the field of polyvinyl alcohol production, specifically relating to a backwashing device for a polymerization reactor and a polymerization reactor. Background Technology

[0002] Polyvinyl alcohol (PVA) is an important chemical raw material widely used in the manufacture of PVA acetal, gasoline-resistant pipes and vinylon, fabric treatment agents, emulsifiers, paper coatings, adhesives, and glues. In the medical field, due to its biocompatibility, it is used in the production of drug carriers and wound dressings. In the packaging industry, it can form films with good barrier properties for food and pharmaceutical packaging. In the textile industry, it is used to manufacture fibers and fabrics to improve strength and abrasion resistance. In the construction industry, it is used as an adhesive and additive to enhance the performance of concrete and mortar.

[0003] The production process of polyvinyl alcohol includes: reacting acetylene and acetic acid to prepare vinyl acetate, then using vinyl acetate as a monomer and methanol as a solvent to polymerize and produce polyvinyl acetate, and finally, the polyvinyl acetate undergoes an alcoholysis reaction to produce polyvinyl alcohol and the byproduct methyl acetate. The polymerization reaction of vinyl acetate takes place in a polymerization reactor, the top of which is equipped with a sight glass, a pressure transmitter diaphragm, and a burst-proof plate. The sight glass is used to observe the flow state, color changes, and reaction progress of the materials inside the polymerization reactor; the pressure transmitter diaphragm is an elastic element located between the measured medium and the transmission mechanism. The pressure transmitter diaphragm can directly sense the pressure inside the reactor and then convert the pressure into an electrical signal for transmission through the actuator body; the burst-proof plate is a thinly designed metal or graphite component. When the pressure inside the reactor suddenly increases to a dangerous level, the burst-proof plate will preferentially rupture to rapidly release energy and prevent the entire container from exploding. However, during the polymerization reaction of vinyl acetate, vinyl acetate self-polymerizes on the surfaces of the polymerization reactor sight glass, pressure transmitter diaphragm, and explosion-proof plate. This makes it impossible to observe the internal operation of the reactor, resulting in inaccurate pressure measurements. The explosion-proof plate cannot rupture in time, making it difficult to release the polymerized material, posing a significant safety hazard. Current practices involve shutting down the reactor within a specified time to remove the vinyl acetate self-polymerized material from the surface of the sight glass, pressure transmitter diaphragm, and explosion-proof plate. This shutdown reduces production and impacts efficiency. Cleaning the pressure transmitter diaphragm with the self-polymerized material is often ineffective, damaging the diaphragm and causing inaccurate measurements. Removing the explosion-proof plate is time-consuming and labor-intensive. Major overhauls and replacements are performed every two years, leaving the polymerization reactor operating with these defects, and making it difficult to discharge material from the reactor in abnormal situations.

[0004] Chinese patent CN213855956U discloses a rinsing device for a sight glass of a reactor, including a rinsing pipe and a flange. The rinsing pipe is hollow and fixedly installed on the reactor. One end of the rinsing pipe is connected to a water supply device, and the other end has a rinsing head. The rinsing head is connected to the rinsing pipe, and its outlet is opposite to the sight glass. The flange is fitted onto the rinsing pipe to connect the water supply device and the flushing device. This patent's rinsing device simply rinses the sight glass without treating the rinsing fluid, resulting in low rinsing efficiency.

[0005] Chinese patent CN222076573U discloses a reaction vessel with a flushing pipeline, comprising a reaction vessel, a support leg fixedly connected to the bottom of the reaction vessel, a cleaning device provided on the side of the reaction vessel, the cleaning device including a base plate, the side of the base plate fixedly connected to the circumference of the reaction vessel, a cleaning agent tank fixedly connected to the top of the base plate, a connecting pipe fixedly passing through the side of the cleaning agent tank, an air bladder fixedly passing through the end of the connecting pipe away from the cleaning agent tank, an outlet pipe fixedly passing through the top of the air bladder, and pipelines fixedly passing through the circumference of the reaction vessel. The flushing pipeline disclosed in this patent is complex and cannot flush the top of the reaction vessel. Utility Model Content

[0006] To address the problems existing in the prior art, this utility model provides a backwashing device for a polymerization reactor, which can quickly clean the vinyl acetate self-polymer from the surfaces of the sight glass, pressure transmitter diaphragm, and explosion-proof plate without stopping the reactor, thus ensuring the normal operation of the polymerization reactor.

[0007] The technical solution adopted in this utility model is as follows: A backwashing device for a polymerization reactor includes nozzles disposed inside the polymerization reactor and arranged below a sight glass, an explosion-proof plate, and a pressure transmitter diaphragm. The nozzles are connected to a first methanol delivery pipeline for conveying methanol. One end of the first methanol delivery pipeline opposite to the nozzles extends out of the polymerization reactor and is connected to the high-temperature methanol outlet of a heater. The low-temperature methanol inlet of the heater is connected to the main methanol delivery pipeline via a first branch pipe.

[0008] Furthermore, a nozzle is arranged below the sight glass, the explosion-proof plate, and the pressure transmitter diaphragm, respectively. The nozzles are aligned with the center of the sight glass, the explosion-proof plate, and the pressure transmitter diaphragm. Preferably, the nozzles are located on the central axis of the sight glass, the explosion-proof plate, and the pressure transmitter diaphragm to achieve all-round rinsing of the sight glass, the explosion-proof plate, and the pressure transmitter diaphragm. The nozzles can be, for example, solid cone atomizing nozzles, fan-shaped nozzles, hollow cone atomizing nozzles, etc.

[0009] Furthermore, after entering the polymerization reactor, the first methanol delivery pipeline forms a bend section, the end of which is connected to a nozzle. The first methanol delivery pipeline includes three parallel pipelines, each of which is connected to a nozzle. The three first methanol delivery pipelines merge into a first total methanol delivery pipeline, which is then connected to the high-temperature methanol outlet of the heater.

[0010] Furthermore, each first methanol delivery pipeline is equipped with a first flow meter and a first flow regulating valve. The first flow meter is connected to the information input terminal of the controller, and the first flow regulating valve is connected to the information output terminal of the controller. The controller interlocks to open or close the first flow regulating valve. At the same time, the first flow meter and the first flow regulating valve are interlocked to control the flow rate of methanol, thereby controlling the impact force of methanol ejected from the nozzle. Each first methanol delivery pipeline is equipped with a first flow meter and a first flow regulating valve to realize individual control of the methanol flow rate in each first methanol delivery pipeline.

[0011] Furthermore, the first methanol main delivery pipeline is equipped with a pressure gauge for monitoring methanol pressure and a temperature gauge for monitoring methanol temperature, both of which are connected to the controller.

[0012] Furthermore, the heater can be, for example, a shell-and-tube heat exchanger or a jacketed heat exchanger. The heater has a high-temperature intermediate medium inlet and a low-temperature intermediate medium outlet. The high-temperature intermediate medium inlet is connected to a high-temperature intermediate medium input pipeline, and the low-temperature intermediate medium outlet is connected to a low-temperature intermediate medium output pipeline. The intermediate medium can be, for example, steam or high-temperature hot water. A high-temperature intermediate medium regulating valve is provided on the high-temperature intermediate medium input pipeline. The high-temperature intermediate medium regulating valve is connected to a controller and interlocked with a temperature monitoring meter. When the methanol temperature monitored by the temperature monitoring meter is high, the high-temperature intermediate medium regulating valve reduces its opening. When the methanol temperature monitored by the temperature monitoring meter is low, the high-temperature intermediate medium regulating valve increases its opening.

[0013] Furthermore, a first control valve is provided on the first branch pipe, and the first control valve is connected to the controller.

[0014] Furthermore, the controller is a programmable logic controller.

[0015] Furthermore, after the methanol delivery main pipe and the vinyl acetate delivery pipe merge, they are connected to the preheater. A check valve is installed on the methanol delivery main pipe between the first branch pipe and the vinyl acetate delivery pipe. The check valve is used to prevent vinyl acetate from entering the heater. The preheater is, for example, a tray type.

[0016] Furthermore, the high-temperature liquid output pipe of the preheater is connected to the reactant inlet of the polymerization reactor, the gas phase output pipe of the polymerization reactor is connected to the heating medium inlet of the preheater, the gas output pipe of the preheater is connected to the high-temperature gas inlet of the condenser, the low-temperature liquid outlet of the condenser is connected to the polymerization reactor via the low-temperature liquid output pipe, and the condenser is equipped with a condensate inlet and a condensate outlet. The condensate inlet is connected to the condensate input pipe, and the condensate outlet is connected to the condensate output pipe.

[0017] This invention further provides a polymerization reactor, which includes the polymerization reactor backwashing device described above.

[0018] The beneficial effects of this utility model are: This invention relates to a backwashing device for a polymerization reactor. A nozzle is installed inside the reactor to rinse the self-polymerized material on the sight glass, explosion-proof plate, and pressure transmitter diaphragm. The nozzle is connected to a heater via a first methanol delivery pipe. The heater heats the methanol supplied from the main methanol delivery pipe. The methanol sprayed from the nozzle originates from the same source as the methanol used as a solvent inside the reactor. The rinsed methanol flows back into the reactor and can be reused as a solvent without introducing other impurities or affecting the reaction. Furthermore, the nozzle is directly connected to the first methanol delivery pipe extending from the reactor, allowing rinsing to occur while the reactor is running. The heated methanol is delivered to the nozzle and sprayed out, using hot methanol to rinse the vinyl acetate self-polymerized material, increasing its solubility and rapidly dissolving the adhering material. Automatic control is achieved by interlocking the first control valve, high-temperature intermediate medium regulating valve, first flow regulating valve, temperature monitor, and first flow meter with a controller. This prevents secondary damage to the sight glass, pressure transmitter diaphragm, and explosion-proof plate, saves manpower, and improves rinsing efficiency. This invention relates to a backwashing device for a polymerization reactor that eliminates the need to stop the reactor to rinse the sight glass, pressure transmitter diaphragm, and explosion-proof plate. It can clean the vinyl acetate self-polymer from the surfaces of the sight glass, pressure transmitter diaphragm, and explosion-proof plate during normal production. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a backwashing device for a polymerization reactor according to the present invention.

[0020] Figure 2 This is a schematic diagram of the diaphragm of the explosion-proof plate.

[0021] Figure 3 This is a schematic diagram showing the connection between the clamp and the diaphragm.

[0022] Figure 4 This is a schematic diagram of the nozzle.

[0023] Figure 5 This is a schematic diagram of a pressure transmitter.

[0024] Explanation of reference numerals in the attached figures: 1-Polymerization reactor, 2-Sight glass, 3-Explosion-proof plate, 301-Diaphragm, 302-Ring plate, 303-Holder, 304-Threaded through hole, 305-Notch, 4-Pressure transmitter diaphragm, 5-Nozzle, 6-First methanol delivery pipeline, 7-Heater, 8-First branch pipe, 9-Methanol delivery main pipeline, 10-Bend section, 11-First main methanol delivery pipeline, 12-First flow meter, 13-First flow regulating valve, 14-Pressure monitoring gauge, 15-Temperature monitoring gauge, 16-High-temperature intermediate medium input pipe 17-Low-temperature intermediate medium output pipeline, 18-High-temperature intermediate medium regulating valve, 19-First control valve, 20-Vinyl acetate conveying pipeline, 21-Preheater, 22-Check valve, 23-High-temperature liquid output pipeline, 24-Gas phase output pipeline, 25-Gas output pipeline, 26-Low-temperature liquid output pipeline, 27-Condensate input pipeline, 28-Condensate output pipeline, 29-Condenser, 30-Explosive material output pipeline, 31-Emergency buffer device, 32-Flange, 33-Transmitter body. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] like Figure 1-5 As shown, a backwashing device for a polymerization reactor includes a nozzle 5 disposed inside the polymerization reactor 1 and arranged below a sight glass 2, an explosion-proof plate 3, and a pressure transmitter diaphragm 4. The sight glass 2, the pressure transmitter diaphragm 4, and the explosion-proof plate 3 are disposed on the top of the polymerization reactor. The nozzle 5 is connected to a first methanol conveying pipe 6 for conveying methanol. One end of the first methanol conveying pipe 6 opposite to the nozzle 5 extends out of the polymerization reactor 1 and is connected to the high-temperature methanol outlet of a heater 7. The low-temperature methanol inlet of the heater 7 is connected to the methanol conveying main pipe 9 via a first branch pipe 8.

[0027] like Figure 1 As shown, a nozzle 5 is arranged below each of the sight glass 2, the explosion-proof plate 3, and the pressure transmitter diaphragm 4. The nozzles 5 are respectively aligned with the center of the sight glass 2, the explosion-proof plate 3, and the pressure transmitter diaphragm 4. The nozzles 5 are preferably located on the central axis of the sight glass 2, the explosion-proof plate 3, and the pressure transmitter diaphragm 4 to achieve all-round rinsing of the sight glass 2, the explosion-proof plate 3, and the pressure transmitter diaphragm 4. The nozzles 5 can be, for example, solid cone atomizing nozzles, fan-shaped nozzles, hollow cone atomizing nozzles, etc.

[0028] like Figure 1 As shown, after the first methanol delivery pipe 6 enters the polymerization reactor 1, it forms a bent section 10. The end of the bent section 10 is connected to the nozzle 5. The first methanol delivery pipe 6 includes three parallel pipes. Each first methanol delivery pipe 6 is connected to a nozzle 5. The three first methanol delivery pipes 6 merge into the first total methanol delivery pipe 11 and are then connected to the high-temperature methanol outlet of the heater 7.

[0029] like Figure 1 As shown, each first methanol conveying pipeline 6 is equipped with a first flow meter 12 and a first flow regulating valve 13. The first flow meter 12 is connected to the information input terminal of the controller, and the first flow regulating valve 13 is connected to the information output terminal of the controller. The controller interlocks to open or close the first flow regulating valve 13. At the same time, the first flow meter 12 and the first flow regulating valve 13 are interlocked to control the flow rate of methanol, thereby controlling the impact force of methanol ejected from the nozzle 5 (for example, the impact force of the sight glass 2 and the explosion-proof plate 3 is controlled at 20 kPa, and the pressure of the pressure transmitter diaphragm 4 is controlled at 10 kPa). Each first methanol conveying pipeline 6 is equipped with a first flow meter 12 and a first flow regulating valve 13 to realize the individual control of the methanol flow rate in each first methanol conveying pipeline 6.

[0030] like Figure 1 As shown, the first methanol main delivery pipeline 11 is equipped with a pressure gauge 14 for monitoring methanol pressure and a temperature gauge 15 for monitoring methanol temperature. Both the pressure gauge 14 and the temperature gauge 15 are connected to the controller.

[0031] like Figure 1 As shown, heater 7 can be, for example, a shell-and-tube heat exchanger or a jacketed heat exchanger. Heater 7 is provided with a high-temperature intermediate medium inlet and a low-temperature intermediate medium outlet. The high-temperature intermediate medium inlet is connected to the high-temperature intermediate medium input pipe 16, and the low-temperature intermediate medium outlet is connected to the low-temperature intermediate medium output pipe 17. The intermediate medium can be, for example, steam or high-temperature hot water. A high-temperature intermediate medium regulating valve 18 is provided on the high-temperature intermediate medium input pipe 16. The high-temperature intermediate medium regulating valve 18 is connected to the controller and interlocked with the temperature monitoring meter 15. When the methanol temperature monitored by the temperature monitoring meter 15 is high, the high-temperature intermediate medium regulating valve 18 reduces its opening. When the methanol temperature monitored by the temperature monitoring meter 15 is low, the high-temperature intermediate medium regulating valve 18 increases its opening. In practical applications, methanol in the methanol main pipe 9 enters the heater 7 through the first branch pipe 8. Methanol and the intermediate medium exchange heat in the heater 7 to increase their own temperature (e.g., to 58-62℃). The heated methanol enters the first methanol main pipe 6 through the first methanol main pipe 11. The methanol is divided into three streams and transported to the nozzles 5 below the sight glass 2, the explosion-proof plate 3, and the pressure transmitter diaphragm 4. After being sprayed out by the nozzles 5, the methanol washes the vinyl acetate self-polymer on the surface of the sight glass 2, the explosion-proof plate 3, and the pressure transmitter diaphragm 4. The washed methanol flows into the polymerization reactor 1 and continues to be used as a solvent.

[0032] like Figure 1 As shown, the first branch pipe 8 is equipped with a first control valve 19, which is connected to the controller.

[0033] The controller is a programmable logic controller, such as a DCS or PLC. It is a type of memory used to store programs internally and execute user-oriented instructions such as logical operations, sequential control, timing, counting, and arithmetic operations. It controls various types of machinery or production processes through digital or analog input / output. The controller sets the time intervals for flushing the sight glass 2, explosion-proof plate 3, and pressure transmitter diaphragm 4 (e.g., flushing the sight glass 2 and pressure transmitter diaphragm 4 every month, and flushing the explosion-proof plate 3 every two months). When the controller controls the opening of the first flow regulating valve 13 on any of the paths, the high-temperature intermediate medium regulating valve 18 and the first control valve 19 open. The high-temperature intermediate medium regulating valve 18 is interlocked with the temperature monitoring meter 15 to control the temperature of methanol output from the heater 7. The first flow meter 12 is interlocked with the first flow regulating valve 13 to control the flow rate of methanol, thus flushing the sight glass 2, explosion-proof plate 3, and pressure transmitter diaphragm 4.

[0034] like Figure 1 As shown, the methanol delivery main pipe 9 and the vinyl acetate delivery pipe 20 merge and are connected to the preheater 21. A check valve 22 is provided on the methanol delivery main pipe 9 between the first branch pipe 8 and the vinyl acetate delivery pipe 20. The check valve 22 is used to prevent vinyl acetate from entering the heater 7. The preheater 21 is, for example, a tray type.

[0035] like Figure 1 As shown, the high-temperature liquid output pipe 23 of the preheater 21 is connected to the reactant inlet of the polymerization reactor 1, the gas phase output pipe 24 of the polymerization reactor 1 is connected to the heating medium inlet of the preheater 21, the gas output pipe 25 of the preheater 21 is connected to the high-temperature gas inlet of the condenser 29, the low-temperature liquid outlet of the condenser 29 is connected to the polymerization reactor 1 via the low-temperature liquid output pipe 26, the condenser 29 is provided with a condensate inlet and a condensate outlet, the condensate inlet is connected to the condensate input pipe 27, and the condensate outlet is connected to the condensate output pipe 28.

[0036] In practical applications, methanol and vinyl acetate enter the preheater 21 via the methanol delivery main 9 and the vinyl acetate delivery pipeline 20, respectively. After being heated by the preheater 21, they are delivered to the polymerization reactor 1 via the high-temperature liquid output pipeline 23. Vinyl acetate reacts in the polymerization reactor 1, with methanol as the solvent. Since the vinyl acetate reaction is an exothermic reaction, heat is released to vaporize vinyl acetate and methanol. The vaporized vinyl acetate and methanol return to the preheater 21 via the gas phase output pipeline 24 to heat the liquid methanol and vinyl acetate. In the preheater 21, the gas phase and liquid phase are in countercurrent contact for heat transfer via the trays. Part of the vaporized vinyl acetate and methanol condenses and enters the polymerization reactor 1, while the other part enters the condenser 29 via the gas output pipeline 25. After condensation in the condenser 29, the vaporized vinyl acetate and methanol enter the polymerization reactor 1 via the low-temperature liquid output pipeline 26.

[0037] Figure 2 and Figure 3 The structure of an explosion-proof plate 3 is shown. The explosion-proof plate 3 includes an arched diaphragm 301 and an annular piece 302 disposed around the periphery of the diaphragm 301. The diaphragm 301 is, for example, arched. The edge of the annular plate 302 has multiple notches 305. The annular plate 302 is fixed between two clamps 303. Each clamp 303 has multiple threaded through holes 304, the positions of which correspond to the positions of the notches 305. Bolts are screwed into the threaded through holes 304 and notches 305 and then tightened with matching nuts to fix the diaphragm 301 between the clamps 303. The clamp 303 above the annular plate 302 is connected to the explosive discharge pipe 30. The other end of the explosive discharge pipe 30 is connected to the emergency buffer device 31. The clamp 303 below the annular plate 302 is connected to the polymerization reactor 1 via a short pipe. The nozzle 5 extends into the short pipe directly opposite the diaphragm 301 of the explosion-proof plate 3. The diameter of the short pipe can be, for example, 10-15 times the equivalent diameter of the nozzle 5. Figure 2 and Figure 3 The structure of one type of explosion-proof plate 3 is shown. The explosion-proof plate 3 of this application can also adopt other forms commonly used in the art, such as notched rupture discs, flat rupture discs, etc. In specific applications, when the pressure of the polymerization reactor 1 exceeds 110 kPa and the temperature exceeds 85°C, the diaphragm 301 of the explosion-proof plate 3 ruptures, and the material of the polymerization reactor 1 is ejected from the explosion-proof plate 3 and enters the accident buffer device 31 through the explosive discharge pipe 30. The explosion-proof plate 3 is replaced every 2 years.

[0038] Figure 5 A schematic diagram of a pressure transmitter is shown. The pressure transmitter includes a flange 32 for connection to a polymerization reactor 1, a diaphragm 4 disposed on the flange 32, and a transmitter body 33 connected to the flange 32. The pressure transmitter is connected to the flange of the polymerization reactor 1 via the flange 32. The diaphragm 4 faces the inside of the polymerization reactor 1, and the nozzle 5 is directly opposite the center of the diaphragm 4. Figure 5 The structure of one type of pressure transmitter is shown, but the pressure transmitter of this application can also adopt other forms commonly used in the art.

[0039] This invention further provides a polymerization reactor including the aforementioned backwashing device.

[0040] According to the backwashing device for polymerization reactor of this utility model, a nozzle is installed inside the polymerization reactor to rinse the self-polymers of the sight glass, explosion-proof plate, and pressure transmitter diaphragm. The nozzle is connected to a heater via a first methanol delivery pipeline. The heater is used to heat the methanol input from the methanol delivery main pipe. The methanol sprayed from the nozzle comes from the same source as the methanol used as a solvent in the polymerization reactor. The methanol after rinsing flows into the polymerization reactor and can be reused as a solvent without introducing other impurities and having no impact on the reaction. The nozzle is directly connected to the first methanol delivery pipeline extending out of the polymerization reactor, allowing rinsing to be performed while the polymerization reactor is running. The methanol is heated by the heater and then delivered to the nozzle and sprayed out. Hot methanol is used to rinse the vinyl acetate self-polymers, increasing the solubility of the vinyl acetate self-polymers and quickly dissolving the attached vinyl acetate self-polymers, ensuring continuous and stable reaction without the need to stop the reactor. The controller interlocks with the first control valve, the high-temperature intermediate medium regulating valve, the first flow regulating valve, the temperature monitor, and the first flow meter to achieve automatic control, avoiding secondary damage to the sight glass, pressure transmitter diaphragm, and explosion-proof plate, saving manpower, and improving rinsing efficiency. By adopting the backwashing device of this invention for polymerization reactors, the problems of regular major overhauls and replacements, as well as the impact on product quality caused by the operation of polymerization reactors with defects, are avoided.

[0041] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A backwashing device for a polymerization reactor, characterized in that, It includes a nozzle (5) disposed inside the polymerization reactor (1) and arranged below the sight glass (2), the explosion-proof plate (3) and the pressure transmitter diaphragm (4). The nozzle (5) is connected to a first methanol conveying pipeline (6) for conveying methanol. The end of the first methanol conveying pipeline (6) opposite to the nozzle (5) extends out of the polymerization reactor (1) and is connected to the high-temperature methanol outlet of the heater (7). The low-temperature methanol inlet of the heater (7) is connected to the methanol conveying main pipeline (9) via a first branch pipe (8).

2. The backwashing device for the polymerization reactor according to claim 1, characterized in that, A nozzle (5) is arranged below each of the sight glass (2), the explosion-proof plate (3), and the pressure transmitter diaphragm (4). The nozzles (5) are respectively aligned with the center of the sight glass (2), the explosion-proof plate (3), and the pressure transmitter diaphragm (4). The nozzles (5) are located on the central axis of the sight glass (2), the explosion-proof plate (3), and the pressure transmitter diaphragm (4).

3. The backwashing device for the polymerization reactor according to claim 1, characterized in that, After entering the polymerization reactor (1), the first methanol delivery pipe (6) forms a bend section (10). The end of the bend section (10) is connected to the nozzle (5). The first methanol delivery pipe (6) includes three parallel pipes. Each first methanol delivery pipe (6) is connected to a nozzle (5). The three first methanol delivery pipes (6) merge into the first total methanol delivery pipe (11) and are then connected to the high-temperature methanol outlet of the heater (7).

4. The backwashing device for the polymerization reactor according to claim 3, characterized in that, Each first methanol delivery pipeline (6) is equipped with a first flow meter (12) and a first flow regulating valve (13). The first flow meter (12) is connected to the information input terminal of the controller, and the first flow regulating valve (13) is connected to the information output terminal of the controller. The controller interlocks to open or close the first flow regulating valve (13), and at the same time, the first flow meter (12) and the first flow regulating valve (13) are interlocked.

5. The backwashing device for the polymerization reactor according to claim 3 or 4, characterized in that, The first methanol main pipeline (11) is equipped with a pressure gauge (14) for monitoring methanol pressure and a temperature gauge (15) for monitoring methanol temperature. Both the pressure gauge (14) and the temperature gauge (15) are connected to the controller.

6. The backwashing device for the polymerization reactor according to claim 5, characterized in that, The heater (7) is equipped with a high temperature intermediate medium inlet and a low temperature intermediate medium outlet. The high temperature intermediate medium inlet is connected to the high temperature intermediate medium input pipe (16), and the low temperature intermediate medium outlet is connected to the low temperature intermediate medium output pipe (17). The high temperature intermediate medium input pipe (16) is equipped with a high temperature intermediate medium regulating valve (18), which is connected to the controller and interlocked with the temperature monitoring meter (15).

7. The backwashing device for the polymerization reactor according to claim 1, characterized in that, A first control valve (19) is provided on the first branch pipe (8), and the first control valve (19) is connected to the controller; and / or After the methanol delivery main pipe (9) merges with the vinyl acetate delivery pipe (20), it is connected to the preheater (21). A check valve (22) is provided on the methanol delivery main pipe (9) between the first branch pipe (8) and the vinyl acetate delivery pipe (20). The check valve (22) is used to prevent vinyl acetate from entering the heater (7).

8. The backwashing device for the polymerization reactor according to any one of claims 4-7, characterized in that, The controller is a programmable logic controller.

9. The backwashing device for the polymerization reactor according to claim 7, characterized in that, The high-temperature liquid output pipe (23) of the preheater (21) is connected to the reactant inlet of the polymerization reactor (1), the gas phase output pipe (24) of the polymerization reactor (1) is connected to the heating medium inlet of the preheater (21), the gas output pipe (25) of the preheater (21) is connected to the high-temperature gas inlet of the condenser (29), the low-temperature liquid outlet of the condenser (29) is connected to the polymerization reactor (1) via the low-temperature liquid output pipe (26), the condenser (29) is provided with a condensate inlet and a condensate outlet, the condensate inlet is connected to the condensate input pipe (27), and the condensate outlet is connected to the condensate output pipe (28).

10. A polymerization reactor, characterized in that, It includes the backwashing device for the polymerization reactor as described in any one of claims 1-9.

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