Polyvinyl chloride production device, polymerization wall coating and flushing system thereof and wall coating and cleaning process

Abstract

The invention discloses a polyvinyl chloride production device, a polymerization wall coating and flushing system and a wall coating and cleaning process thereof, and belongs to the technical field of chemical production. The PVC production device comprises a PVC polymerization kettle and a kettle top condenser, two spraying valves are arranged on the top of the PVC polymerization kettle, and valve rods of the spraying valves extend into the kettle; a condenser top spray valve is arranged on a top seal head of the kettle top condenser, and a valve rod of the condenser top spray valve extends into the seal head; and a condenser bottom spray valve is arranged in the bottom space of the kettle top condenser and is horizontally arranged below a lower tube plate of the kettle top condenser. The polymerization wall coating and flushing system of the polyvinyl chloride production device comprises the polyvinyl chloride production device and an anti-sticking agent tank. The wall coating and flushing process comprises the steps of wall coating before feeding, wall coating and flushing and discharging and flushing. According to the invention, kettle sticking substances in the polymerization kettle and the condenser before feeding of each kettle are greatly reduced, the frequency of opening and cleaning of the polymerization kettle is reduced, and the utilization rate and production capacity of the polymerization kettle are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical production, relates to the field of polyvinyl chloride (PVC) production, and specifically relates to a polyvinyl chloride production device, a polymerized wall coating, a flushing system, and a wall coating and cleaning process. Background Art

[0002] With the development and scale of PVC polymerization process, large-scale polymerization kettles have been widely used. Since the PVC polymerization process is an exothermic polymerization reaction of vinyl chloride (VCM) monomer, and the heat release is large, about 368 kcal is released per kilogram of VCM monomer reaction. Relying solely on jacket heat removal and cooling pipe heat removal in the polymerization kettle can no longer meet the heat removal requirements required by production capacity. Adding a top condenser to the kettle, using the evaporation of VCM in the kettle, and using shell-side cooling water in the top condenser to liquefy the evaporated gas phase VCM has become an effective measure to increase the heat removal capacity of large PVC polymerization kettles. Due to the entrainment of initiators, the gas phase VCM in the upper part of the kettle rises to the top head through the condenser tubes, liquefies, and flows back to the kettle through the heat exchange tube wall. There will be different degrees of polymerization in the process, and the generated PVC polymer will adhere to the inner wall of the top head of the condenser, the inner wall of the tubes, and the inner wall of the bottom of the condenser, which seriously affects the heat transfer. In addition, the inner wall of the polymerization kettle and the internal parts such as the agitator shaft, agitator blades, and internal cooling tubes are also prone to adhesion during long-term operation, especially near the gas-liquid interface and the connection between the agitator shaft and the agitator blades. The sticking phenomenon is more serious. In addition to affecting the heat removal effect of polymerization, if the attached polymer enters the next polymerization reaction kettle, it will also form fish eyes in the PVC finished resin, seriously affecting the quality of PVC products.

[0003] In PVC production equipment, whether it is the suspension method for producing general-purpose PVC resin, or the micro-suspension method and emulsion method for producing paste resin, there is a relatively serious phenomenon of kettle sticking, and the kettle has to be opened frequently for high-pressure cleaning, which increases the labor intensity of operators and reduces the utilization rate of polymerization kettles, affecting production capacity. Some devices of large kettles with reflux condensers in the existing PVC industry are designed with anti-sticking kettle agent wall coating and flushing schemes. The typical design method is: the polymerization kettle wall is coated with anti-sticking kettle agent by straight pipe spraying or fixed nozzle spraying, and the fixed flushing nozzle installed on the top of the kettle is used for flushing. It was found in production operation that the straight pipe spraying or fixed nozzle spraying coverage is insufficient, and the wall coating effect is not ideal; the fixed flushing nozzle often blocks the nozzle hole due to the contact with VCM gas phase during the polymerization process, and the nozzle processing flow is small, the flushing range is small, and there are flushing dead corners. In order to solve these problems, it is necessary to design a reasonable wall coating and flushing process. On the one hand, a reasonable wall coating method is used to form an anti-stick kettle film on the inner wall and internal surface of the polymerization kettle and condenser to prevent the polymer from being attached to the inner wall of the kettle, the internal parts of the agitator and the condenser in large quantities; on the other hand, a reasonable flushing plan for the unloading process needs to be designed to perform flushing without dead ends to avoid the residual polymer that has already adhered in the kettle and affect the quality of the final product. Summary of the invention

[0004] One of the purposes of the present invention is to provide a polyvinyl chloride production device to solve the problem of kettle sticking in the PVC polymerization production process in the prior art.

[0005] A second object of the present invention is to provide a polymer coating and flushing system for a polyvinyl chloride production device.

[0006] The third object of the present invention is to provide a wall coating and cleaning process for the polyvinyl chloride production device.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] The present invention discloses a polyvinyl chloride production device, comprising a PVC polymerization kettle and a kettle top condenser, wherein two spray valves are arranged on the top of the PVC polymerization kettle, and the valve stems of the two spray valves are both extended into the kettle;

[0009] A condenser top spray valve is provided at the top head of the kettle top condenser, and its valve stem extends into the head; a condenser bottom spray valve is provided in the bottom space of the kettle top condenser and is horizontally installed below the lower tube plate of the kettle top condenser.

[0010] In some embodiments of the present invention, two spray valves on the top of the PVC polymerization kettle are symmetrically distributed with the center line of the polymerization kettle as the axis.

[0011] In some implementation schemes of the present invention, each spray valve is a rotary spray valve; when opened, the spray pipe extends out of the sealed cavity and rotates; when closed, the spray pipe retracts into the sealed cavity.

[0012] In some embodiments of the present invention, after the two spray valves on the top of the PVC polymerization kettle are opened, the spray pipes thereof extend to a position 500 to 1500 mm above the gas-liquid interface during the polymerization kettle reaction.

[0013] In some embodiments of the present invention, the condenser bottom spray valve is horizontally installed 400 to 1000 mm below the lower tube plate. After the spray valve is opened, the position where the spray pipe extends is located on the center line of the kettle top condenser;

[0014] After the condenser top spray valve is opened, the spray pipe extends to a position 400 to 1000 mm above the upper tube plate.

[0015] This position configuration ensures that the wall coating and spraying range can cover the entire area of ​​the top condenser and the inside of the polymerization kettle.

[0016] The invention discloses a polyvinyl chloride production device polymer coating wall and flushing system, comprising the polyvinyl chloride production device mentioned above, and also comprising an anti-sticking kettle agent tank;

[0017] The anti-sticking agent tank is connected to the two spray valves on the top of the PVC polymerization kettle, the spray valve on the top of the condenser and the spray valve on the top of the condenser through an anti-sticking agent delivery line;

[0018] Each spray valve is also connected to a flushing water delivery line and a steam delivery line;

[0019] Preferably, the steam delivery line corresponding to each spray valve is connected to its corresponding anti-sticking agent delivery line and then connected to the corresponding spray valve, so that the anti-sticking agent is atomized under the action of steam and then enters the spray valve.

[0020] The polymerized wall coating and flushing process of the polyvinyl chloride production device or the polyvinyl chloride wall coating and flushing system disclosed in the present invention comprises the steps of wall coating and wall flushing before adding materials, and the step of flushing after unloading materials.

[0021] In some embodiments of the present invention, the wall coating and wall coating flushing steps before adding materials include:

[0022] S1. Kettle top condenser wall coating: After the anti-sticking agent is mixed with high-temperature steam, it is sent to the spray valves at the top and bottom of the kettle top condenser respectively, and the upper head, tubes and bottom of the condenser are sprayed to form an anti-sticking kettle film on the inner wall of the condenser. The liquefied wall coating liquid flows into the PVC polymerization kettle by gravity;

[0023] S2. PVC polymerization kettle wall coating: After the kettle top condenser wall coating is completed, the anti-sticking kettle agent is mixed with high-temperature steam and sent to the two spray valves on the top of the PVC polymerization kettle respectively to spray the inner wall and internal surface of the polymerization kettle to form an anti-sticking kettle film; then the liquefied wall coating liquid in the polymerization kettle is flushed.

[0024] In some embodiments of the present invention, after the wall coating and wall flushing steps before feeding are completed, the polymerization feeding and reaction procedures are entered; after the reaction is completed, the unloading procedure is entered; in the early stage of unloading, the top condenser of the kettle is unloaded and flushed once through the two spray valves of the kettle top condenser to flush the PVC solids entrained by the gas phase and adhered to the condenser into the polymerization kettle slurry; in the middle and late stages of unloading, the polymerization kettle is flushed twice to ensure the flushing effect.

[0025] In some embodiments of the present invention, the polymerizer is flushed twice in the middle and late stages of the unloading process, specifically comprising:

[0026] In the middle of unloading, the polymerization kettle is flushed for the first time through the two spray valves on the top of the polymerization kettle to flush the inner wall and internal parts of the upper and middle parts of the polymerization kettle;

[0027] At the end of unloading, when the polymerization kettle is about to be emptied, the polymerization kettle is flushed for the second time through the two spray valves on the top of the polymerization kettle, and the polymer adhered to the inner wall, internal parts and bottom of the polymerization kettle is thoroughly flushed and discharged together with the slurry;

[0028] Preferably, the first flushing of the polymerization kettle is performed when the liquid level of the material is lowered below the second layer of blades of the stirring paddle in the polymerization kettle;

[0029] Preferably, when there is a layer of stirring paddle in the polymerization kettle, the polymerization kettle is flushed for the first time when the discharge reaches about two-thirds of the total amount.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] According to the characteristics of PVC polymerization batch operation, the present invention proposes a process scheme in which electric or pneumatic rotary spray valves are respectively designed on the top of the PVC polymerization kettle, the upper head of the kettle top condenser and the bottom space, and anti-sticking kettle agent is applied to the wall and unloading is flushed before polymerization feeding and during unloading, so as to solve the problem of kettle sticking in the PVC polymerization production process.

[0032] In the present invention, when coating the wall, the anti-sticking kettle liquid and high-temperature steam are mixed in the pipeline, and the atomized anti-sticking kettle agent is sprayed in through the spray valve. The rotating spray pipe makes the atomized anti-sticking kettle agent spray over a larger range. The atomized anti-sticking kettle agent condenses on the inner wall, internal parts and inner wall of the top condenser of the polymerization kettle, and forms a layer of oleophobic and hydrophilic film. Due to the formation of a layer of anti-sticking kettle film, the VCM oil droplets are separated from the metal wall of the kettle during the polymerization reaction, thereby effectively preventing or reducing the occurrence of sticking kettle; when the wall coating flushing and unloading flushing are performed, the rotation of the spray pipe ensures that all parts are covered in all directions, so that the kettle wall, internal parts and the top condenser of the kettle can be fully flushed. The use of a rotating spray valve not only avoids the problem of polymer clogging the spray hole in the traditional fixed nozzle method, but also makes the wall coating and flushing have better effects.

[0033] The wall coating and flushing process of the present invention can greatly reduce the sticky materials in the polymerization kettle and condenser before each kettle is charged, reduce the frequency of opening the polymerization kettle for cleaning, and can achieve continuous production of more than 800 kettles without opening the kettle for high-pressure cleaning, thereby improving the utilization rate and production capacity of the polymerization kettle. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Attached Figure 1 It is a schematic structural diagram of the polymerized wall coating and flushing system of the polyvinyl chloride production device of the present invention.

[0035] Attached Figure 2 This is a schematic diagram of the kettle top condenser structure.

[0036] The names corresponding to the reference numerals are:

[0037] 1: PVC polymerization kettle, 2: kettle top condenser, 3: anti-sticking kettle agent tank, 4: anti-sticking kettle agent feeding pump;

[0038] P11, P12: polymerizer spray valve, P13: first anti-sticking agent valve, P14: first steam valve, P15: first flushing water valve, P16: polymerizer discharge valve, P17: drain valve, P18: inner cooling pipe cooling water regulating valve, P19: jacket cooling water regulating valve;

[0039] P21: condenser top spray valve, P22: condenser bottom spray valve, P23: second anti-sticking agent valve, P24: second steam valve, P25: second flushing water valve, P26: third anti-sticking agent valve, P27: third steam valve, P28: third flushing water valve;

[0040] 101: kettle top spray material conveying line, 201: condenser top spray material conveying line, 202: condenser bottom spray material conveying line;

[0041] 300: anti-sticking agent delivery line, 301: first anti-sticking agent delivery line, 302: second anti-sticking agent delivery line, 303: third anti-sticking agent delivery line,

[0042] 400: steam transmission bus, 401: first steam transmission line, 402: second steam transmission line, 403: third steam transmission line;

[0043] 500: condenser flushing water delivery line, 501: first flushing water delivery line, 502: second flushing water delivery line, 503: third flushing water delivery line;

[0044] FQI-P1: condenser flushing water cumulative flow meter, FQI-P2: polymerization kettle flushing water cumulative flow meter, FV-CT1 steam flow control valve, FIC-CT1: steam flow cumulative flow meter, FV-CT2: anti-sticking kettle agent flow control valve, FIQC-CT2: anti-sticking kettle agent cumulative flow meter, FIQ-BD01: unloading flow meter, PU-1E: polymerization kettle unloading pump, LS-P182: liquid level switch. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0046] Example 1

[0047] As attached Figure 1 As shown, the present invention discloses a polyvinyl chloride production device, which includes a PVC polymerization kettle 1 and a kettle top condenser 2 connected to the PVC polymerization kettle 1;

[0048] The PVC polymerization kettle 1 is provided with an agitator and an internal cooling pipe, and two polymerization kettle spray valves P11 and P12 are provided on the top of the kettle, and the valve stems of the two spray valves are extended into the kettle;

[0049] A condenser top spray valve P21 is provided at the top head of the kettle top condenser 2, and its valve stem extends into the head; a condenser bottom spray valve P22 is provided in the bottom space of the kettle top condenser 2, and is horizontally installed below the lower tube plate of the kettle top condenser 2.

[0050] Example 2

[0051] As attached Figure 1 As shown, the present invention discloses a polyvinyl chloride production device, which includes a PVC polymerization kettle 1 and a kettle top condenser 2 connected to the PVC polymerization kettle 1;

[0052] The PVC polymerization kettle 1 is provided with an agitator and an internal cooling pipe, and two polymerization kettle spray valves P11 and P12 are provided on the top of the kettle, and the valve stems of the two spray valves are extended into the kettle;

[0053] A condenser top spray valve P21 is provided at the top head of the kettle top condenser 2, and its valve stem extends into the head; a condenser bottom spray valve P22 is provided in the bottom space of the kettle top condenser 2, and is horizontally installed below the lower tube plate of the kettle top condenser 2.

[0054] The two polymerization kettle spray valves P11 and P12 are symmetrically distributed with the center line of the PVC polymerization kettle 1 as the axis.

[0055] This embodiment 2 provides a more preferred technical solution based on the embodiment 1. Specifically, the two polymerization kettle spray valves P11 and P12 are symmetrically distributed with the center line of the PVC polymerization kettle 1 as the axis.

[0056] Example 3

[0057] As attached Figure 1 As shown, the present invention discloses a polyvinyl chloride production device, which includes a PVC polymerization kettle 1 and a kettle top condenser 2 connected to the PVC polymerization kettle 1;

[0058] The PVC polymerization kettle 1 is provided with an agitator and an internal cooling pipe, and two polymerization kettle spray valves P11 and P12 are provided on the top of the kettle, and the valve stems of the two spray valves are extended into the kettle;

[0059] A condenser top spray valve P21 is provided at the top head of the kettle top condenser 2, and its valve stem extends into the head; a condenser bottom spray valve P22 is provided in the bottom space of the kettle top condenser 2, and is horizontally installed below the lower tube plate of the kettle top condenser 2.

[0060] The two polymerization kettle spray valves P11 and P12 are symmetrically distributed with the center line of the PVC polymerization kettle 1 as the axis.

[0061] Each spray valve (P11, P12, P21, P22) is a rotary spray valve; when opened, the spray pipe extends out of the sealed cavity and rotates; when closed, the spray pipe retracts into the sealed cavity.

[0062] This embodiment 3 provides a more preferred technical solution based on embodiment 2. Specifically, each spray valve (P11, P12, P21, P22) is a rotary spray valve; when opened, the spray pipe extends out of the sealed cavity and rotates; when closed, the spray pipe retracts into the sealed cavity.

[0063] Example 4

[0064] As attached Figure 1As shown, the present invention discloses a polyvinyl chloride production device, which includes a PVC polymerization kettle 1 and a kettle top condenser 2 connected to the PVC polymerization kettle 1;

[0065] The PVC polymerization kettle 1 is provided with an agitator and an internal cooling pipe, and two polymerization kettle spray valves P11 and P12 are provided on the top of the kettle, and the valve stems of the two spray valves are extended into the kettle;

[0066] A condenser top spray valve P21 is provided at the top head of the kettle top condenser 2, and its valve stem extends into the head; a condenser bottom spray valve P22 is provided in the bottom space of the kettle top condenser 2, and is horizontally installed below the lower tube plate of the kettle top condenser 2.

[0067] The two polymerization kettle spray valves P11 and P12 are symmetrically distributed with the center line of the PVC polymerization kettle 1 as the axis.

[0068] Each spray valve (P11, P12, P21, P22) is a rotary spray valve; when opened, the spray pipe extends out of the sealed cavity and rotates; when closed, the spray pipe retracts into the sealed cavity.

[0069] After the polymerizer spray valves P11 and P12 are opened, the spray pipes extend 500 to 1500 mm above the gas-liquid interface during the reaction of the PVC polymerizer 1.

[0070] Based on Example 3, this Example 4 provides a more preferred installation position for the two polymerization kettle spray valves P11 and P12. Specifically, after the two polymerization kettle spray valves are opened, the extension position of their spray pipes is 500 to 1500 mm above the gas-liquid interface during the reaction process of the PVC polymerization kettle 1.

[0071] Example 5

[0072] As attached Figure 1 As shown, the present invention discloses a polyvinyl chloride production device, which includes a PVC polymerization kettle 1 and a kettle top condenser 2 connected to the PVC polymerization kettle 1;

[0073] The PVC polymerization kettle 1 is provided with an agitator and an internal cooling pipe, and two polymerization kettle spray valves P11 and P12 are provided on the top of the kettle, and the valve stems of the two spray valves are extended into the kettle;

[0074] A condenser top spray valve P21 is provided at the top head of the kettle top condenser 2, and its valve stem extends into the head; a condenser bottom spray valve P22 is provided in the bottom space of the kettle top condenser 2, and is horizontally installed below the lower tube plate of the kettle top condenser 2.

[0075] The two polymerization kettle spray valves P11 and P12 are symmetrically distributed with the center line of the PVC polymerization kettle 1 as the axis.

[0076] Each spray valve (P11, P12, P21, P22) is a rotary spray valve; when opened, the spray pipe extends out of the sealed cavity and rotates; when closed, the spray pipe retracts into the sealed cavity.

[0077] After the polymerizer spray valves P11 and P12 are opened, the spray pipes extend 500 to 1500 mm above the gas-liquid interface during the reaction of the PVC polymerizer 1.

[0078] The condenser bottom spray valve P22 arranged at the bottom of the kettle top condenser 2 is horizontally installed 400 to 1000 mm below the lower tube plate. After the condenser bottom spray valve P22 is opened, the position where its spray pipe extends is located on the center line of the kettle top condenser 2.

[0079] Based on Example 4, this Example 5 provides a technical solution for a more preferred installation position of the condenser bottom spray valve P22. Specifically: the condenser bottom spray valve P22 is horizontally installed 400 to 1000 mm below the lower tube plate. After the condenser bottom spray valve P22 is opened, the position where its spray pipe extends is located on the center line of the kettle top condenser 2.

[0080] Example 6

[0081] As attached Figure 1 As shown, the present invention discloses a polyvinyl chloride production device, which includes a PVC polymerization kettle 1 and a kettle top condenser 2 connected to the PVC polymerization kettle 1;

[0082] The PVC polymerization kettle 1 is provided with an agitator and an internal cooling pipe, and two polymerization kettle spray valves P11 and P12 are provided on the top of the kettle, and the valve stems of the two spray valves are extended into the kettle;

[0083] A condenser top spray valve P21 is provided at the top head of the kettle top condenser 2, and its valve stem extends into the head; a condenser bottom spray valve P22 is provided in the bottom space of the kettle top condenser 2, and is horizontally installed below the lower tube plate of the kettle top condenser 2.

[0084] The two polymerization kettle spray valves P11 and P12 are symmetrically distributed with the center line of the PVC polymerization kettle 1 as the axis.

[0085] Each spray valve (P11, P12, P21, P22) is a rotary spray valve; when opened, the spray pipe extends out of the sealed cavity and rotates; when closed, the spray pipe retracts into the sealed cavity.

[0086] After the polymerizer spray valves P11 and P12 are opened, the spray pipes extend 500 to 1500 mm above the gas-liquid interface during the reaction of the PVC polymerizer 1.

[0087] The condenser bottom spray valve P22 arranged at the bottom of the kettle top condenser 2 is horizontally installed 400 to 1000 mm below the lower tube plate. After the condenser bottom spray valve P22 is opened, the position where its spray pipe extends is located on the center line of the kettle top condenser 2.

[0088] After the condenser top spray valve P21 arranged at the top head of the kettle top condenser 2 is opened, the position where its spray pipe extends is 400 to 1000 mm above the upper tube plate.

[0089] Based on Example 5, this Example 6 provides a technical solution for a more preferred installation position of the condenser top spray valve P21. Specifically: after the condenser top spray valve P21 is opened, the position where its spray pipe extends is 400 to 1000 mm above the upper tube plate.

[0090] Example 7

[0091] This embodiment discloses a polymer coating and flushing system for a polyvinyl chloride production device, which includes the polyvinyl chloride production device described in Example 6, and also includes an anti-sticking agent tank 3, and the anti-sticking agent tank 3 is connected to an anti-sticking agent delivery bus 300.

[0092] The two polymerization reactor spray valves P11 and P12 are respectively connected to the reactor top spray material conveying line 101 through pipelines, the condenser top spray valve P21 is connected to the condenser top spray material conveying line 201, and the condenser bottom spray valve P22 is connected to the condenser bottom spray material conveying line 202;

[0093] The kettle top spray material conveying line 101 is connected to the first anti-sticking kettle agent conveying line 301, the first steam conveying line 401 and the first flushing water conveying line 501;

[0094] The condenser top spray material delivery line 201 is connected to the second anti-sticking kettle agent delivery line 302, the second steam delivery line 402 and the second flushing water delivery line 502;

[0095] The condenser bottom spray material delivery line 202 is connected to the third anti-sticking kettle agent delivery line 303, the third steam delivery line 403 and the third flushing water delivery line 503;

[0096] The first anti-adhesion agent delivery line 301 is provided with a first anti-adhesion agent valve P13, the first steam delivery line 401 is provided with a first steam valve P14, and the first flushing water delivery line 501 is provided with a first flushing water valve P15 and a polymerization kettle flushing water cumulative flow meter FQI-P2;

[0097] A second anti-sticking agent valve P23 is provided on the second anti-sticking agent delivery line 302, a second steam valve P24 is provided on the second steam delivery line 402, and a second flushing water valve P25 is provided on the second flushing water delivery line 502;

[0098] A second anti-adhesion agent valve P26 is provided on the third anti-adhesion agent delivery line 303, a third steam valve P27 is provided on the third steam delivery line 403, and a third flushing water valve P28 is provided on the third flushing water delivery line 503;

[0099] The first anti-sticking agent delivery line 301, the second anti-sticking agent delivery line 302 and the third anti-sticking agent delivery line 303 are all connected by the anti-sticking agent delivery bus 300; the anti-sticking agent delivery bus 300 is provided with an anti-sticking agent feeding pump 4, an anti-sticking agent cumulative amount flow meter FIQC-CT2 and an anti-sticking agent flow control valve FV-CT2, and the anti-sticking agent cumulative amount flow meter FIQC-CT2 and the anti-sticking agent flow control valve FV-CT2 are signal-connected;

[0100] The second flushing water delivery line 502 and the third flushing water delivery line 503 are both connected to the condenser flushing water delivery line 500, and the condenser flushing water delivery line 500 is connected to the condenser flushing water cumulative flow meter FQI-P1;

[0101] The first steam delivery line 401, the second steam delivery line 402 and the third steam delivery line 403 are all connected by the steam delivery bus 400. The steam delivery bus 400 is provided with a steam flow control valve FV-CT1 and a steam flow cumulative flow meter FIC-CT1. The steam flow control valve FV-CT1 and the steam flow cumulative flow meter FIC-CT1 are signal-connected.

[0102] A polymerization kettle discharge valve P16 is provided at the bottom of the PVC polymerization kettle 1, which is respectively connected to a drainage line and a discharge line, and a drainage valve P17 is provided on the drainage line;

[0103] An inner cooling pipe cooling water regulating valve P18 is provided on the cooling water delivery line of the inner cooling pipe of the polymerization kettle, and a jacket cooling water regulating valve P19 is provided on the cooling water delivery line of the jacket of the polymerization kettle.

[0104] Example 8

[0105] This embodiment discloses a wall coating and flushing process using the polyvinyl chloride polymer wall coating and cleaning system of embodiment 7, and the specific steps are as follows:

[0106] 1. Wall coating and wall flushing before adding materials

[0107] 1. Before the wall coating begins, the cooling water regulating valve P18 of the inner cooling pipe of the polymerization kettle and the jacket cooling water regulating valve P19 are given an opening of 20-50%, and the cooling water of the condenser jacket is maintained at a small flow rate under the control of the flow limiting orifice plate so that the atomized anti-sticking kettle can condense into a film on the surface.

[0108] 2. Open the polymerization kettle spray valves P11 and P12, the condenser top spray valve P21 and the condenser bottom spray valve P22. The spray pipe extends out of the sealing cavity and starts to rotate.

[0109] 3. First, coat the top condenser. Set the steam flow control valve FV-CT1 to 10-50% opening. Open the second steam valve P24 and the third steam valve P27. After the valves are fully opened, set the steam flow control loop to 1000-3000 kg / h (the steam mass flow control is 6-8 times the mass flow of the anti-sticking agent), and purge the pipeline for 10-50 seconds.

[0110] 4. After the steam purge is completed, start the anti-sticking agent feed pump 4 and set the anti-sticking agent flow control valve FV-CT2 to an initial opening of 10-30%. Open the second anti-sticking agent valve P23 and the third anti-sticking agent valve P26. After the valves are fully opened, set the flow rate of the anti-sticking agent flow control loop to 100-500 kg / h. The anti-sticking agent is mixed with steam in the pipeline, atomized by high-temperature steam, and enters the condenser through the condenser top spray valve P21 and the condenser bottom spray valve P22, spraying the upper head, tubes and bottom of the condenser to form an anti-sticking film on the inner wall. The liquefied wall coating liquid flows into the polymerization kettle by gravity.

[0111] 5. When the cumulative amount of anti-sticking agent added reaches the set value, first close the second anti-sticking agent valve P23 and the third anti-sticking agent valve P26, and stop the anti-sticking agent feeding pump 4.

[0112] 6. After the steam continues to blow for 10 to 50 seconds, close the second steam valve P24 and the third steam valve P27 to ensure that no condensate remains in the pipe, and then close the condenser top spray valve P21 and the condenser bottom spray valve P22.

[0113] 7. Then carry out the coating of the polymerization kettle wall. Open the first steam valve P14, set the steam flow control loop FIC-CT1 to a flow rate of 1000-3000 kg / h (the steam mass flow rate is controlled to be 6-8 times the flow rate of the anti-sticking kettle agent), and purge the pipeline for 10-50 seconds.

[0114] 8. After the pipeline is purged, start the anti-sticking agent feed pump 4 and set the anti-sticking agent flow control valve FV-CT2 to an initial opening of 10-30%. Open the first anti-sticking agent valve P13. After the valve is fully opened, set the anti-sticking agent flow control loop to a flow rate of 100-500 kg / h. The anti-sticking agent is mixed with steam in the pipeline, atomized by high-temperature steam, and enters the polymerization kettle through the spray valve to form an anti-sticking film on the inner wall and internal surface of the polymerization kettle.

[0115] 9. When the cumulative amount of anti-sticking agent added reaches the set value, close the first anti-sticking agent valve P13 and stop the anti-sticking agent feeding pump 4.

[0116] 10. After waiting for the steam to continue blowing for 10 to 50 seconds, close the first steam valve P14 to ensure that no condensate remains in the pipe.

[0117] 11. After closing the first steam valve P14, wait for 100 to 300 seconds to allow the atomized anti-sticking agent to condense and form a film on the inner wall and internal surface of the polymerization reactor.

[0118] 12. Open the first flushing water valve P15 to flush the liquefied wall coating liquid in the polymerization kettle, and open the polymerization kettle discharge valve P16 and drain valve P17 to drain the water.

[0119] 13. Wait for the accumulated flushing water flow to reach the set flushing water volume of 0.2 to 0.8 m 3 Then, close the first flushing water valve P15.

[0120] 14. After the first flushing water valve P15 is closed, close the polymerization kettle spray valves P11 and P12.

[0121] 15. After the wall coating and flushing water in the reactor is discharged, close the polymerization reactor discharge valve P16 and drain valve P17, and the wall coating and wall flushing process before adding materials is completed.

[0122] 2. Unloading and flushing

[0123] DCS enters the feeding and reaction procedures according to the batch control procedure, and enters the unloading procedure after the reaction is completed. At the beginning of unloading, the top condenser of the kettle is unloaded and flushed once through the spray valve, and the PVC solids entrained by the gas phase and bonded to the condenser are flushed into the polymerization kettle slurry. The polymerization kettle is flushed twice in the middle and late stages of unloading to ensure the flushing effect. The first spray valve flushing: when the unloading liquid level drops below the second layer of paddles (if there is only one layer of stirring, the unloading is about two-thirds of the total amount), the spray valve is used to flush the upper and middle inner walls and internal parts of the polymerization kettle; the second spray valve flushing: when the slurry is about to be emptied, the unloading liquid level just drops below the bottom paddle, and high-pressure water is passed through the spray valve on the top of the polymerization kettle again to thoroughly flush the polymer bonded to the inner wall, internal parts and bottom of the polymerization kettle and discharge it with the slurry. The operating steps are as follows:

[0124] 1. When the polymerization kettle unloading pump PU-1E is started, the kettle top condenser is flushed first, and the condenser top spray valve P21 and the condenser bottom spray valve P22 are opened.

[0125] 2. Open the second flushing water valve P25 and the third flushing water valve P28;

[0126] 3. Wait for the flushing water cumulative flow meter to reach the set flushing water volume of 1.0~2.5m 3 Then, close the second flushing water valve P25 and the third flushing water valve P28.

[0127] 4. After the second flushing water valve P25 and the third flushing water valve P28 are closed, close the condenser top spray valve P21 and the condenser bottom spray valve P22, the spray pipe is retracted, and the spray port is sealed.

[0128] 5. When the cumulative amount of the discharge flow meter FIQ-BD01 shows that the discharge of the polymerization kettle has reached a certain set value, the first spray valve flushing of the polymerization kettle is carried out, and the spray valves P11 and P12 of the polymerization kettle are opened.

[0129] 6. Open the first flushing water valve P15.

[0130] 7. Wait for the flushing water to reach the set amount. The flushing water volume is 1.0 to 2.5 m 3 Afterwards, close the first flushing water valve P15 and close the polymerization kettle spray valves P11 and P12.

[0131] 8. Wait again until the material level in the polymerization kettle drops to below the bottom paddle and is about to be emptied, that is, when the liquid level switch LS-P182 alarms low liquid level, open the first flushing water valve P15 again, and open the polymerization kettle spray valves P11 and P12 for secondary flushing of the polymerization kettle spray valves.

[0132] 9. Wait for the flushing water to reach the set amount. The flushing water volume is 0.2 to 0.8 m 3 , close the first flushing water valve P15, and after it is fully closed, close the polymerization kettle spray valves P11 and P12.

[0133] The unloading and flushing of the kettle top condenser and polymerization kettle spray valve are completed.

[0134] In this embodiment, each spray valve is an electric or pneumatic rotary spray valve. The designed flushing water volume of a single spray valve is 20 to 50 m 3 / h, the flushing water pressure provided is 1.5~3.0MPa.G, and the S-shaped spray port of the selected spray valve has an opening width of about 1~3mm, so that the flushing water is sprayed out of the spray port in a linear state. When the spray valve is opened, the spray pipe extends out of the sealed cavity and rotates; when it is closed, the spray pipe retracts into the sealed cavity. This method avoids the VCM monomer from contacting the spray port during the reaction process and causing self-polymerization and blockage.

[0135] Finally, it should be noted that the above embodiments are only preferred embodiments of the present invention to illustrate the technical solution of the present invention, but not to limit it, and certainly not to limit the patent scope of the present invention. Any changes or modifications that have no substantial significance on the main design concept and spirit of the present invention, which solve technical problems consistent with the present invention, should be included in the protection scope of the present invention; in addition, the direct or indirect application of the technical solution of the present invention in other related technical fields should also be included in the patent protection scope of the present invention.

Claims

1. A polyvinyl chloride production device, comprising a PVC polymerization kettle and a kettle top condenser, characterized in that: Two spray valves are arranged on the top of the PVC polymerization kettle, and the valve stems of the two spray valves extend into the kettle; A condenser top spray valve is provided at the top head of the kettle top condenser, and its valve stem extends into the head; a condenser bottom spray valve is provided in the bottom space of the kettle top condenser and is horizontally installed below the lower tube plate of the kettle top condenser.

2. A polyvinyl chloride production device according to claim 1, characterized in that: The two spray valves on the top of the PVC polymerization kettle are symmetrically distributed with the center line of the polymerization kettle as the axis.

3. A polyvinyl chloride production device according to claim 1, characterized in that: Each spray valve is a rotary spray valve; when opened, the spray pipe extends out of the sealing cavity and rotates; when closed, the spray pipe retracts into the sealing cavity.

4. A polyvinyl chloride production device according to claim 3, characterized in that: After the two spray valves on the top of the PVC polymerization kettle are opened, the spray pipes extend to a position 500 to 1500 mm above the gas-liquid interface during the polymerization kettle reaction.

5. A polyvinyl chloride production device according to claim 3, characterized in that: The bottom spray valve of the condenser is horizontally installed 400 to 1000 mm below the lower tube plate. After the spray valve is opened, the position where the spray pipe extends is located on the center line of the kettle top condenser; after the spray valve of the top spray valve of the condenser is opened, the position where the spray pipe extends is 400 to 1000 mm above the upper tube plate.

6. A polymer coating and flushing system for a polyvinyl chloride production device, characterized in that: A polyvinyl chloride production device comprising any one of claims 1 to 5, further comprising an anti-sticking kettle agent tank; The anti-sticking agent tank is connected to the two spray valves on the top of the PVC polymerization kettle, the spray valve on the top of the condenser and the spray valve on the top of the condenser through an anti-sticking agent delivery line; Each spray valve is also connected to a flushing water delivery line and a steam delivery line; Preferably, the steam delivery line corresponding to each spray valve is connected to its corresponding anti-sticking agent delivery line and then connected to the corresponding spray valve, so that the anti-sticking agent is atomized under the action of steam and then enters the spray valve.

7. The wall coating and flushing process of the polyvinyl chloride production device according to any one of claims 1 to 5 or the polyvinyl chloride production device according to claim 6, characterized in that: The method includes the steps of coating the wall and flushing the wall before adding materials, and the step of flushing after unloading.

8. The wall coating and flushing process of the polyvinyl chloride production device according to claim 7, characterized in that: The steps of coating and flushing the wall before adding materials include: S1. Kettle top condenser wall coating: After the anti-sticking agent is mixed with high-temperature steam, it is sent to the spray valves at the top and bottom of the kettle top condenser respectively, and the upper head, tubes and bottom of the condenser are sprayed to form an anti-sticking kettle film on the inner wall of the condenser. The liquefied wall coating liquid flows into the PVC polymerization kettle by gravity; S2. PVC polymerization kettle wall coating: After the kettle top condenser wall coating is completed, the anti-sticking kettle agent is mixed with high-temperature steam and sent to the two spray valves on the top of the PVC polymerization kettle respectively to spray the inner wall and internal surface of the polymerization kettle to form an anti-sticking kettle film; then the liquefied wall coating liquid in the polymerization kettle is flushed.

9. The wall coating and flushing process of the polyvinyl chloride production device according to claim 8, characterized in that: After the wall coating and wall flushing steps before feeding are completed, the polymerization feeding and reaction procedures are entered; after the reaction is completed, the unloading procedure is entered; in the early stage of unloading, the top condenser of the kettle is unloaded and flushed once through the two spray valves of the kettle top condenser to flush the PVC solids entrained by the gas phase and adhered to the condenser into the polymerization kettle slurry; in the middle and late stages of unloading, the polymerization kettle is flushed twice to ensure the flushing effect.

10. The wall coating and flushing process of the polyvinyl chloride production device according to claim 8, characterized in that: The two flushing of the polymerization kettle in the middle and late stages of unloading specifically include: In the middle of unloading, the polymerization kettle is flushed for the first time through the two spray valves on the top of the polymerization kettle to flush the inner wall and internal parts of the upper and middle parts of the polymerization kettle; At the end of unloading, when the polymerization kettle is about to be emptied, the polymerization kettle is flushed for the second time through the two spray valves on the top of the polymerization kettle, and the polymer adhered to the inner wall, internal parts and bottom of the polymerization kettle is thoroughly flushed and discharged together with the slurry; Preferably, the first flushing of the polymerization kettle is performed when the liquid level of the material is lowered below the second layer of blades of the stirring paddle in the polymerization kettle; Preferably, when there is a layer of stirring paddle in the polymerization kettle, the polymerization kettle is flushed for the first time when the discharge reaches about two-thirds of the total amount.

Images