Initiator adding device for vinyl chloride polymerization kettle

Abstract

The initiator adding device comprises the polymerization kettle, a shaft seat is fixedly arranged at the inner bottom of the polymerization kettle, a stirring shaft is rotatably arranged on the shaft seat, the upper end of the stirring shaft penetrates through the top of the polymerization kettle, a plurality of stirring blades are uniformly arranged on the stirring shaft, and a motor is fixed at the top of the stirring shaft. An output shaft of the motor is coaxially connected with the stirring shaft, a through hole is formed in the bottom of the shaft seat, penetrates through the kettle body and is communicated with a water injection root pipeline below the kettle body, the other end of the water injection root pipeline is communicated with a deionized water injection pipeline and an initiator adding pipeline, and one end, far away from the kettle body, of the deionized water injection pipeline is communicated with a metering pump; one end, far away from the kettle body, of the initiator adding pipeline is communicated with a storage tank, and the initiator adding pipeline is also communicated with a centrifugal pump. Flowing deionized water cools the polymerization kettle and the shaft seat, the self-polymerization phenomenon of an initiator is reduced, the flowing deionized water can continuously impact the initiator added into the through hole in the shaft seat, and self-polymerization of the initiator is prevented.

Description

Technical Field

[0001] This utility model belongs to the field of production technology in the chemical polyvinyl chloride industry, and relates to an initiator addition device for a vinyl chloride polymerization reactor. Background Technology

[0002] In the chemical industry, polyvinyl chloride (PVC), as a widely used synthetic resin, occupies an important position in many industries due to its excellent mechanical properties, outstanding chemical resistance, good electrical insulation, and superior processing performance. PVC resin is produced through a polymerization reaction, and the initiator, as an indispensable key auxiliary agent in this polymerization reaction, has a decisive influence on the polymerization rate, molecular weight, and other core properties of PVC resin, thus directly affecting the quality and application performance of PVC products.

[0003] The temperatures released during the polymerization reaction and the friction generated by the stirring shaft and bearing can cause self-polymerization during the initiator addition process, leading to frequent self-polymerization in the initiator addition pipe. Once the initiator addition pipe becomes blocked due to self-polymerization, it directly blocks the normal initiator addition path, which not only greatly complicates process control of the polymerization reaction but also has a serious negative impact on the quality of PVC resin. After the initiator addition pipe becomes blocked, to ensure continuous and stable production, the machine must be shut down, the pipe disassembled, and the self-polymerized material removed. This process not only reduces the operating efficiency of the polymerization reactor but also prolongs downtime for maintenance and reduces equipment utilization, resulting in significant economic losses for the company. Therefore, designing an effective initiator addition device to prevent self-polymerization in the pipe is of great significance for improving PVC resin production efficiency and product quality. Utility Model Content

[0004] The purpose of this invention is to provide an initiator addition device for a vinyl chloride polymerization reactor, which features the ability to reduce the temperature during initiator addition, thereby preventing self-polymerization in the initiator addition pipeline.

[0005] The technical solution adopted in this utility model is an initiator addition device for a vinyl chloride polymerization reactor, including a polymerization reactor. A shaft seat is fixedly installed at the bottom of the polymerization reactor, and a stirring shaft is rotatably installed on the shaft seat. The upper end of the stirring shaft penetrates through the top of the polymerization reactor. Multiple stirring blades are evenly arranged on the stirring shaft. A motor is fixed at the top of the stirring shaft, and the output shaft of the motor is coaxially connected to the stirring shaft. A through hole is opened at the bottom of the shaft seat, which penetrates through the reactor body and is connected to a water injection root pipe below the reactor body. The other end of the water injection root pipe is connected to a deionized water injection pipe and an initiator addition pipe. A metering pump is connected to the end of the deionized water injection pipe away from the reactor body, and a storage tank is connected to the end of the initiator addition pipe away from the reactor body. A centrifugal pump is also connected to the initiator addition pipe.

[0006] The features of this utility model also include:

[0007] The storage tank is fitted with a cooling sleeve, the inner diameter of which is the same as the outer diameter of the storage tank.

[0008] A weighing tank is installed on the initiator addition pipeline between the centrifugal pump and the storage tank. The inlet and outlet of the weighing tank are connected to the initiator addition pipeline.

[0009] A first one-way check valve is installed on the deionized water injection pipe near the root of the injection pipe, a second one-way check valve is installed on the initiator addition pipe near the root of the injection pipe, and a third one-way check valve is installed on the root of the injection pipe.

[0010] A deionized water flushing pipeline is installed on one side of the weighing tank, and the deionized water flushing pipeline is connected to the inside of the weighing tank.

[0011] An automatic control valve is installed on the initiator addition pipeline between the storage tank and the weighing tank.

[0012] A mass flow meter is installed on the outlet pipeline of the centrifugal pump.

[0013] The outlet pressure of the metering pump and centrifugal pump is set higher than the reaction pressure inside the polymerization reactor.

[0014] The beneficial effects of this utility model are:

[0015] 1. During the operation of the polymerization reactor, the deionized water metering pump continuously injects deionized water into the reactor through the stirring shaft base. Even when the initiator is added, the deionized water injection from the metering pump will not be interrupted, which lowers the temperature at the initiator addition point. Furthermore, the continuous impact of the deionized water on the initiator addition point prevents self-polymerization blockage in the initiator addition pipe, thereby ensuring that the polymerization reaction system is in a safe state and guaranteeing the stable operation of the production system.

[0016] 2. This invention can reduce downtime for polymerization reactor maintenance and improve equipment utilization. Actual calculations show that it can reduce unplanned maintenance time for polymerization reactors by approximately 190 hours per year.

[0017] 3. Based on the unplanned downtime for maintenance and the number of downtimes in the polymerization reactor, the annual PVC resin production can be increased by approximately 300 tons.

[0018] 4. Achieving precise initiator addition and effective integration with the stirring system helps optimize the reaction process and improve the quality of PVC resin products and the stability of equipment operation. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the initiator addition device of this utility model;

[0020] Figure 2 This is a schematic diagram of the connection between the initiator addition pipeline and the polymerization reactor.

[0021] In the diagram: 1. Metering pump; 2. Polymerization reactor; 3. Shaft seat; 4. Storage tank; 5. Weighing tank; 6. Centrifugal pump; 7. Cooling jacket; 8. First one-way check valve; 9. Second one-way check valve; 10. Third one-way check valve; 11. Deionized water injection pipeline; 12. Initiator addition pipeline; 13. Reactor body; 14. Stirring shaft; 15. Water injection root pipeline; 16. Deionized flushing pipeline; 17. Automatic control valve; 18. Mass flow meter. Detailed Implementation

[0022] The following detailed description is provided in conjunction with specific implementation methods.

[0023] This invention provides an initiator addition device for a vinyl chloride polymerization reactor, such as... Figure 1 and Figure 2 As shown, the system includes a polymerization reactor 2. A bearing seat 3 is fixed to the bottom of the reactor 2. A stirring shaft 14 is rotatably connected to the bearing seat 3. The upper end of the stirring shaft 14 penetrates the top of the polymerization reactor 2. Multiple stirring blades are evenly fixed to the stirring shaft 14. A motor is connected to the top of the stirring shaft 14, and the motor's output shaft is coaxially connected to the stirring shaft 14. A through hole is opened at the bottom of the bearing seat 3, and the through hole also penetrates the reactor body 13. A water injection root pipe 15 is connected to the through hole at the bottom of the reactor body 13. The other end of the water injection root pipe 15 is connected to a deionized water injection pipe 11. The initiator addition pipe 12 and the deionized water injection pipe 11, located away from the reactor body 13, are connected to a metering pump 1. The metering pump 1 pumps deionized water into the polymerization reactor 2. The initiator addition pipe 12, located away from the reactor body 13, is connected to a storage tank 4. The initiator is added to the inlet of the storage tank 4 and stored therein. The outlet of the storage tank 4 is connected to the initiator addition pipe 12. A centrifugal pump 6 is also connected to the initiator addition pipe 12, located between the storage tank 4 and the reactor body 13. The centrifugal pump 6 pumps the initiator from the storage tank 4 into the polymerization reactor 2. During the reaction inside the vinyl chloride polymerization reactor, while the initiator is added to the initiator addition pipe 12, deionized water is added to the polymerization reactor 2 through the deionized water injection pipe 11. This prevents the initiator from self-polymerizing at the bottom of the polymerization reactor 2.

[0024] Example 1

[0025] An initiator addition device for a vinyl chloride polymerization reactor includes a polymerization reactor 2. A bearing seat 3 is fixed to the bottom of the interior of the polymerization reactor 2. A stirring shaft 14 is rotatably connected to the bearing seat 3. The upper end of the stirring shaft 14 penetrates the top of the polymerization reactor 2. Multiple stirring blades are also evenly fixed on the stirring shaft 14. A motor is connected to the top of the stirring shaft 14. The output shaft of the motor is coaxially connected to the stirring shaft 14. A through hole is opened at the bottom of the bearing seat 3, and the through hole passes through the reactor body 13. A water injection root pipe 15 is connected to the through hole at the bottom of the reactor body 13. The other end of the water injection root pipe 15 is connected to a deionized water injection pipe 11 and an initiator addition pipe 12.

[0026] The deionized water injection pipe 11 is connected to a metering pump 1 at the end away from the vessel body 13. The initiator addition pipe 12 is connected to a storage tank 4 at the end away from the vessel body 13. A centrifugal pump 6 is also connected to the initiator addition pipe 12. The centrifugal pump 6 is located on the initiator addition pipe 12 between the storage tank 4 and the vessel body 13.

[0027] Example 2

[0028] An initiator addition device for a vinyl chloride polymerization reactor includes a polymerization reactor 2. A bearing seat 3 is fixed to the bottom of the interior of the polymerization reactor 2. A stirring shaft 14 is rotatably connected to the bearing seat 3. The upper end of the stirring shaft 14 passes through the top of the polymerization reactor 2. Multiple stirring blades are also evenly fixed on the stirring shaft 14. A motor is connected to the top of the stirring shaft 14. The output shaft of the motor is coaxially connected to the stirring shaft 14. A through hole is opened at the bottom of the bearing seat 3, and the through hole passes through the reactor body 13.

[0029] A water injection root pipe 15 is connected to the through hole at the bottom of the vessel body 13. The other end of the water injection root pipe 15 is connected to an deionized water injection pipe 11 and an initiator addition pipe 12.

[0030] The deionized water injection pipe 11 is connected to a metering pump 1 at the end away from the vessel body 13. The initiator addition pipe 12 is connected to a storage tank 4 at the end away from the vessel body 13. A cooling sleeve 7 is fitted on the outside of the storage tank 4. The inner diameter of the cooling sleeve 7 is the same as the outer diameter of the storage tank 4. A centrifugal pump 6 is also connected to the initiator addition pipe 12. The centrifugal pump 6 is located on the initiator addition pipe 12 between the storage tank 4 and the vessel body 13.

[0031] Example 3

[0032] An initiator addition device for a vinyl chloride polymerization reactor includes a polymerization reactor 2. A bearing seat 3 is fixed to the bottom of the interior of the polymerization reactor 2. A stirring shaft 14 is rotatably connected to the bearing seat 3. The upper end of the stirring shaft 14 passes through the top of the polymerization reactor 2. Multiple stirring blades are also evenly fixed on the stirring shaft 14. A motor is connected to the top of the stirring shaft 14. The output shaft of the motor is coaxially connected to the stirring shaft 14. A through hole is opened at the bottom of the bearing seat 3, and the through hole passes through the reactor body 13.

[0033] A water injection root pipe 15 is connected to the through hole at the bottom of the vessel body 13. The other end of the water injection root pipe 15 is connected to an deionized water injection pipe 11 and an initiator addition pipe 12.

[0034] The deionized water injection pipe 11 is connected to a metering pump 1 at the end away from the vessel body 13. The initiator addition pipe 12 is connected to a storage tank 4 at the end away from the vessel body 13. A cooling sleeve 7 is fitted on the outside of the storage tank 4. The inner diameter of the cooling sleeve 7 is the same as the outer diameter of the storage tank 4. A centrifugal pump 6 is also connected to the initiator addition pipe 12. The centrifugal pump 6 is located on the initiator addition pipe 12 between the storage tank 4 and the vessel body 13.

[0035] A weighing tank 5 is installed on the initiator addition pipeline 12 between the centrifugal pump 6 and the storage tank 4. The inlet and outlet of the weighing tank 5 are connected to the initiator addition pipeline 12, and the weighing tank 5 accurately weighs the initiator to be added.

[0036] Example 4

[0037] An initiator addition device for a vinyl chloride polymerization reactor includes a polymerization reactor 2. A bearing seat 3 is fixed to the bottom of the interior of the polymerization reactor 2. A stirring shaft 14 is rotatably connected to the bearing seat 3. The upper end of the stirring shaft 14 passes through the top of the polymerization reactor 2. Multiple stirring blades are also evenly fixed on the stirring shaft 14. A motor is connected to the top of the stirring shaft 14. The output shaft of the motor is coaxially connected to the stirring shaft 14. A through hole is opened at the bottom of the bearing seat 3, and the through hole passes through the reactor body 13.

[0038] A water injection root pipe 15 is connected to the through hole at the bottom of the vessel body 13. The other end of the water injection root pipe 15 is connected to an deionized water injection pipe 11 and an initiator addition pipe 12.

[0039] A first one-way check valve 8 is installed on the deionized water injection pipe 11 near the water injection root pipe 15. A second one-way check valve 9 is installed on the initiator addition pipe 12 near the water injection root pipe 15. A third one-way check valve 10 is installed on the water injection root pipe 15 near the vessel body 13. This can prevent the materials added to the three pipes from crossing each other.

[0040] A metering pump 1 is connected to the end of the deionized water injection pipe 11 furthest from the vessel body 13. A storage tank 4 is connected to the end of the initiator addition pipe 12 furthest from the vessel body 13. A cooling sleeve 7 is fitted over the storage tank 4, with the inner diameter of the cooling sleeve 7 matching the outer diameter of the storage tank 4. A centrifugal pump 6 is also connected to the initiator addition pipe 12, located between the storage tank 4 and the vessel body 13. A weighing tank 5 is installed on the initiator addition pipe 12 between the centrifugal pump 6 and the storage tank 4, with its inlet and outlet connected to the initiator addition pipe 12.

[0041] Example 5

[0042] An initiator addition device for a vinyl chloride polymerization reactor includes a polymerization reactor 2. A bearing seat 3 is fixed to the bottom of the interior of the polymerization reactor 2. A stirring shaft 14 is rotatably connected to the bearing seat 3. The upper end of the stirring shaft 14 passes through the top of the polymerization reactor 2. Multiple stirring blades are also evenly fixed on the stirring shaft 14. A motor is connected to the top of the stirring shaft 14. The output shaft of the motor is coaxially connected to the stirring shaft 14. A through hole is opened at the bottom of the bearing seat 3, and the through hole passes through the reactor body 13.

[0043] A water injection root pipe 15 is connected to the through hole below the vessel body 13. The other end of the water injection root pipe 15 is connected to a deionized water injection pipe 11 and an initiator addition pipe 12. A first one-way check valve 8 is installed on the deionized water injection pipe 11 near the water injection root pipe 15. A second one-way check valve 9 is installed on the initiator addition pipe 12 near the water injection root pipe 15. A third one-way check valve 10 is installed on the water injection root pipe 15 near the vessel body 13.

[0044] A metering pump 1 is connected to the end of the deionized water injection pipe 11 away from the vessel body 13. A storage tank 4 is connected to the end of the initiator addition pipe 12 away from the vessel body 13. A cooling sleeve 7 is fitted around the outside of the storage tank 4, and the inner diameter of the cooling sleeve 7 is the same as the outer diameter of the storage tank 4. A centrifugal pump 6 is also connected to the initiator addition pipe 12, which is located between the storage tank 4 and the vessel body 13. A weighing tank 5 is installed on the initiator addition pipe 12 between the centrifugal pump 6 and the storage tank 4. An automatic control valve 17 is installed on the initiator addition pipe 12 between the storage tank 4 and the weighing tank 5 to control the amount of initiator added. The inlet and outlet of the weighing tank 5 are connected to the initiator addition pipe 12. A deionized water flushing pipe 16 is installed on one side of the weighing tank 5, and the outlet of the deionized water flushing pipe 16 is connected to the inside of the weighing tank 5. The deionized water flushing pipe 16 can be used to flush away the residual initiator inside the weighing tank 5.

[0045] Example 6

[0046] An initiator addition device for a vinyl chloride polymerization reactor includes a polymerization reactor 2. A bearing seat 3 is fixed to the bottom of the interior of the polymerization reactor 2. A stirring shaft 14 is rotatably connected to the bearing seat 3. The upper end of the stirring shaft 14 passes through the top of the polymerization reactor 2. Multiple stirring blades are also evenly fixed on the stirring shaft 14. A motor is connected to the top of the stirring shaft 14. The output shaft of the motor is coaxially connected to the stirring shaft 14. A through hole is opened at the bottom of the bearing seat 3, and the through hole passes through the reactor body 13.

[0047] A water injection root pipe 15 is connected to the through hole below the vessel body 13. The other end of the water injection root pipe 15 is connected to a deionized water injection pipe 11 and an initiator addition pipe 12. A first one-way check valve 8 is installed on the deionized water injection pipe 11 near the water injection root pipe 15. A second one-way check valve 9 is installed on the initiator addition pipe 12 near the water injection root pipe 15. A third one-way check valve 10 is installed on the water injection root pipe 15 near the vessel body 13.

[0048] The deionized water injection pipe 11 is connected to a metering pump 1 at the end away from the reactor body 13. The initiator addition pipe 12 is connected to a storage tank 4 at the end away from the reactor body 13. A cooling sleeve 7 is fitted on the outside of the storage tank 4. The inner diameter of the cooling sleeve 7 is the same as the outer diameter of the storage tank 4. A centrifugal pump 6 is also connected to the initiator addition pipe 12. The centrifugal pump 6 is located on the initiator addition pipe 12 between the storage tank 4 and the reactor body 13. The outlet pressure values ​​of the metering pump 1 and the centrifugal pump 6 are set to be greater than the reaction pressure inside the polymerization reactor 2, so as to ensure that deionized water and initiator can be continuously added to the polymerization reactor 2. A weighing tank 5 is installed on the initiator inlet pipe 12 between the centrifugal pump 6 and the storage tank 4. An automatic control valve 17 is installed on the initiator inlet pipe 12 between the storage tank 4 and the weighing tank 5 to control the amount of initiator added. A mass flow meter 18 is installed at the outlet of the centrifugal pump 6 to measure and record the initiator pumped out by the centrifugal pump 6. The inlet and outlet of the weighing tank 5 are connected to the initiator inlet pipe 12. A deionized water flushing line 16 is installed on one side of the weighing tank 5. The outlet of the deionized water flushing line 16 is connected to the inside of the weighing tank 5. The deionized water flushing line 16 can be used to flush away the residual initiator inside the weighing tank 5.

[0049] The working principle of the initiator addition device for vinyl chloride polymerization reactor of this utility model is as follows: Deionized water is connected to metering pump 1, and initiator is added to storage tank 4 through the inlet of storage tank 4. Chilled brine is introduced through cooling jacket 7 to cool the initiator in storage tank 4. Then, reactants are added through the reactor inlet. The motor, metering pump 1, and centrifugal pump 6 are started. The automatic control valve 17 and mass flow meter 18 are opened. Metering pump 1 then pumps deionized water through deionized water injection pipe 11 into water injection root pipe 15, and it flows through the first one-way check valve 8. Centrifugal pump 6 adds initiator from storage tank 4 to the reactor inlet. The initiator is pumped into tank 4 through pipeline 12 and then into the water injection root pipeline 15. Specifically, the initiator first flows into weighing tank 5 through automatic control valve 17. After the required amount is accurately weighed in weighing tank 5, automatic control valve 17 closes. Simultaneously, deionized water flushing pipeline 16 flushes the residual initiator in weighing tank 5, ensuring that the residual initiator is flushed into polymerization reactor 2. Then, centrifugal pump 6 provides power to pump it into the water injection root pipeline 15, passing through mass flow meter 18 and the second one-way check valve 9. Mass flow meter 18 measures and records the amount of initiator flowing through. Deionized water and initiator are continuously pumped into the water injection root pipeline 15, flowing together through the third one-way check valve 10. Afterward, it flows into polymerization reactor 2 through the through-holes at the bottom of reactor body 13 and shaft seat 3. The presence of the first one-way check valve 8, the second one-way check valve 9, and the third one-way check valve 10 prevents cross-contamination of the added materials. During the reaction, by continuously adding flowing deionized water and initiator, on the one hand, the flowing deionized water cools the polymerization kettle 2 and the bearing seat 3, reducing the self-polymerization of the initiator; on the other hand, the flowing deionized water continuously impacts the initiator added into the through hole at the bearing seat 3, preventing the initiator from self-polymerizing.

Claims

1. An initiator addition device for a vinyl chloride polymerization reactor, characterized in that, The assembly includes a polymerization reactor (2), with a bearing seat (3) fixedly installed at the bottom of the reactor (2). A stirring shaft (14) is rotatably installed on the bearing seat (3). The upper end of the stirring shaft (14) passes through the top of the polymerization reactor (2). Multiple stirring blades are evenly arranged on the stirring shaft (14). A motor is fixed at the top of the stirring shaft (14). The output shaft of the motor is coaxially connected to the stirring shaft (14). A through hole is opened at the bottom of the bearing seat (3). The through hole passes through the reactor body (13) and is connected to a water injection root pipe (15) below the reactor body (13). The other end of the water injection root pipe (15) is connected to an ionless water injection pipe (11) and an initiator addition pipe (12). The end of the ionless water injection pipe (11) away from the reactor body (13) is connected to a metering pump (1). The end of the initiator addition pipe (12) away from the reactor body (13) is connected to a storage tank (4). A centrifugal pump (6) is also connected to the initiator addition pipe (12).

2. The initiator addition device for a vinyl chloride polymerization reactor according to claim 1, characterized in that, The storage tank (4) is fitted with a cooling sleeve (7) on the outside, and the inner diameter of the cooling sleeve (7) is the same as the outer diameter of the storage tank (4).

3. The initiator addition device for a vinyl chloride polymerization reactor according to claim 1, characterized in that, A weighing tank (5) is installed on the initiator addition pipeline (12) between the centrifugal pump (6) and the storage tank (4), and the inlet and outlet of the weighing tank (5) are connected to the initiator addition pipeline (12).

4. The initiator addition device for a vinyl chloride polymerization reactor according to claim 1, characterized in that, A first one-way check valve (8) is provided on the deionized water injection pipe (11) near the water injection root pipe (15), a second one-way check valve (9) is provided on the initiator addition pipe (12) near the water injection root pipe (15), and a third one-way check valve (10) is provided on the water injection root pipe (15).

5. The initiator addition device for a vinyl chloride polymerization reactor according to claim 3, characterized in that, A deionized water flushing pipeline (16) is provided on one side of the weighing tank (5), and the deionized water flushing pipeline (16) is connected to the inside of the weighing tank (5).

6. The initiator addition device for a vinyl chloride polymerization reactor according to claim 3, characterized in that, An automatic control valve (17) is installed on the initiator addition pipeline (12) between the storage tank (4) and the weighing tank (5).

7. The initiator addition device for a vinyl chloride polymerization reactor according to claim 1, characterized in that, The centrifugal pump (6) is equipped with a mass flow meter (18) on its outlet pipeline.

8. The initiator addition device for a vinyl chloride polymerization reactor according to claim 1, characterized in that, The outlet pressure of the metering pump (1) and the centrifugal pump (6) is higher than the reaction pressure inside the polymerization reactor (2).

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