Polymerizer for PVC seed micro-suspension paste resin production and manufacturing method of polymerizer

Abstract

The present application relates to a kind of polymerizers for PVC seed microsuspension paste resin production, the manufacturing method of polymerizer, the side wall of polymerizer is inner jacket composite board;Inner jacket composite board includes the outer wall of kettle outside, the inside composite board of inside, form a jacket gap layer between them;Inside composite board includes stainless steel base layer and metal zirconium coating, metal zirconium coating is immediately adjacent to jacket gap layer, stainless steel base layer is immediately adjacent to the inner chamber of polymerizer;Jacket gap layer as the passage of refrigerant flow, it has helical guide vane in it.The side wall of the polymerizer of the present application adopts inside composite board structure, metal zirconium coating is isolated from chloride ion in refrigerant on the one hand, eliminates the problem of corrosion failure of kettle wall, prolongs the service period of equipment, on the other hand, metal zirconium heat conduction performance is excellent, and the realization of global uniform heat transfer is matched with helical guide vane in jacket, accurately and stably polymerization reaction temperature, long-term anticorrosion and high-efficiency heat transfer are simultaneously considered, and the product quality of PVC seed microsuspension paste resin is stabilized.

Description

Technical Field

[0001] This invention relates to the field of polymer chemical technology, and in particular to a polymerization reactor and a method for manufacturing a polymerization reactor for the production of PVC seed micro-suspension paste resin. Background Technology

[0002] Polyvinyl chloride (PVC) paste resin, as an important polymer material, has been widely used in artificial leather, wallpaper, flooring, coatings, and foamed products due to its excellent paste-forming properties, chemical stability, and ease of processing. The seed micro-suspension method, one of the mainstream processes for preparing PVC paste resin, involves preparing seed latex through emulsion polymerization, followed by subsequent stripping and drying processes to obtain the finished product. This method offers significant advantages such as controllable particle size distribution and good paste viscosity stability. However, with the increasing demands for product quality and production efficiency from downstream applications, existing production facilities still face numerous challenges in terms of safety, continuity, and process stability.

[0003] In the existing production process of PVC seed micro-suspension paste resin, the polymerization reactor, as the core reaction equipment, directly affects the efficiency of heat removal and the service life of the equipment due to its material and structural design. Traditional polymerization reactors are usually made of a single stainless steel material, and the cooling side is in long-term contact with chloride ion-containing media, which is prone to pitting corrosion and stress corrosion cracking. This not only shortens the equipment maintenance interval, but also reduces the accuracy of reaction temperature control due to the decrease in heat transfer coefficient, thus affecting the uniformity of the polymerization reaction and the consistency of product quality. In addition, the existing steam stripping and drying processes are mostly intermittent operations with frequent material transfer, low VCM monomer recovery efficiency, and poor connection between defoaming and steam stripping, which can easily cause material loss and environmental pollution, making it difficult to meet the needs of modern continuous production.

[0004] To address the aforementioned technical bottlenecks, there is an urgent need to develop a polymerization reactor structure that combines corrosion resistance and efficient heat transfer, and to optimize the continuous connection of post-processing steps such as defoaming, vaporization, and drying, in order to improve the safety and continuity of the PVC seed micro-suspension paste resin production process and ensure the stability of product quality. Based on this, this invention proposes a polymerization reactor for the production of PVC seed micro-suspension paste resin and a method for manufacturing the polymerization reactor. The aim is to solve the aforementioned technical bottlenecks and achieve the goal of long-cycle operation and high-quality product industrial production through structural innovation of the composite plate in the inner jacket of the polymerization reactor and a fully continuous process design. Summary of the Invention

[0005] This invention provides a polymerization reactor for the production of PVC seed micro-suspension paste resin and a method for manufacturing the polymerization reactor, aiming to solve the problems of traditional polymerization reactors being susceptible to chloride ion corrosion on the cooling side of the jacket and having poor heat exchange uniformity. The sidewall of the polymerization reactor of this invention adopts an inner jacket composite plate structure with zirconium coating. The stainless steel base of the inner composite plate and the metal zirconium coating are composite formed by explosive welding and mechanical rolling. The zirconium coating faces the coolant side of the jacket to isolate corrosive media. Spiral guide plates are arranged in the jacket gap, which can enhance the disturbance of coolant flow, improve the heat exchange uniformity of the reactor, effectively improve the temperature control accuracy of the polymerization process, extend the service life of the polymerization reactor, and stabilize the production quality of PVC seed micro-suspension paste resin.

[0006] The present invention adopts the following technical solution:

[0007] A polymerization reactor for producing PVC seed micro-suspension paste resin, wherein the sidewall of the polymerization reactor B1 is an inner jacketed composite plate; the inner jacketed composite plate includes an outer outer wall W and an inner inner composite plate H, with a jacket gap layer between them; the inner composite plate H includes a stainless steel base layer B114 and a zirconium cladding B115, the zirconium cladding B115 being adjacent to the jacket gap layer, and the stainless steel base layer B114 being adjacent to the inner cavity of the polymerization reactor B1; the jacket gap layer serves as a channel for refrigerant flow and has a spiral guide plate B105 inside.

[0008] Preferably, the zirconium cladding B115 is of type Zr702 with a thickness of 1.5–2.0 mm, and the stainless steel base layer B114 is of type 316L with a thickness of 4.0–6.0 mm; furthermore, the stainless steel surface roughness R… a ≤0.1μm.

[0009] Preferably, the inner composite plate H is made of stainless steel and zirconium metal through explosive welding and mechanical rolling processes, and then rolled into a plate. A small piece of zirconium layer is milled off at the welding point between the inner composite plate H and the guide plate B105, so that the guide plate B105 is welded to the exposed stainless steel base layer B114. A protective layer is formed at the welding point by transition layer nickel welding.

[0010] Preferably, the guide plate B105 has a width of 1.5 to 2 mm, a pitch of 2.0 to 3.0 mm, and a chamfer of 15° to 30°.

[0011] Furthermore, the vacuum falling film mechanical distribution stripping tower D6 is connected to the first spiral plate heat exchanger D2.

[0012] A method for manufacturing polymerization reactor B1 in the polymerization reactor for producing PVC seed micro-suspension paste resin as described above includes the following steps:

[0013] S1. Weld the stainless steel base layer B114 and the zirconium cladding layer B115 into a whole using explosive welding.

[0014] S2. Rolling to produce an integrated composite plate with a stainless steel base layer B114 and a zirconium cladding layer B115.

[0015] S3. Roll the integrated composite panel into a cylinder;

[0016] S4. Partially mill away the zirconium layer at each welding point on the zirconium surface of the cylinder to expose the internal stainless steel base layer B114.

[0017] S5. The guide plate B105 with the spiral structure is fully welded and fixed on the exposed stainless steel base layer B114.

[0018] S6. Assemble the outer wall W of the vessel to form the jacket gap layer. After alignment, weld and fix the outer wall W of the vessel to the guide plate B105.

[0019] S7. After the weld flaw detection is qualified, a nickel transition layer is deposited on the weld surface;

[0020] S8. On the side of the nickel transition layer facing the jacket gap, fill the milled groove with pure zirconium welding material, and after grinding, the zirconium surface is flush with the original zirconium layer of the cylinder.

[0021] S9. Overall flaw detection confirms that the refrigerant contacts the zirconium cladding layer B115, but not the stainless steel base layer B114 or the nickel transition layer.

[0022] The beneficial effects of this invention are as follows:

[0023] 1) The sidewall of the polymerization reactor of this invention adopts an inner composite plate structure. The inner composite plate includes a stainless steel base layer B114 facing the inner cavity of the reactor and a metal zirconium cladding B115 that fits the gap of the jacket. The refrigerant flows into the jacket gap from the inner jacket inlet B107 and is discharged through the inner jacket outlet B113. The metal zirconium cladding isolates chloride ions in the refrigerant, eliminates the problem of reactor wall corrosion failure, and greatly extends the service life of the equipment. On the other hand, the metal zirconium has excellent thermal conductivity. Combined with the spiral guide plate in the jacket, it can achieve uniform heat exchange throughout the entire area, accurately stabilize the polymerization reaction temperature, and simultaneously take into account long-term corrosion protection and efficient heat transfer, thus stabilizing the quality of the finished PVC seed micro-suspension paste resin.

[0024] 2) This polymerization reactor preparation method effectively overcomes multiple manufacturing challenges, such as the composite of zirconium steel and dissimilar metals, the easy generation of brittle phases when directly welding carbon steel guide plates and zirconium cladding, the damage of zirconium anti-corrosion surface layer during welding, and the corrosion of the substrate by the jacket refrigerant. First, a high-strength metallurgical composite of stainless steel base and zirconium cladding is achieved through explosive welding combined with mechanical rolling, ensuring that the cylinder has both structural pressure-bearing capacity and chloride ion corrosion resistance. Then, the guide plate is welded on the stainless steel substrate by partially milling off the zirconium layer, and a nickel transition layer is used to isolate the dissimilar metal interface. Finally, zirconium material is overlaid to restore the complete anti-corrosion surface layer. This method not only firmly fixes the spiral guide plate to optimize the heat exchange uniformity of the jacket refrigerant, but also ensures that only the zirconium layer contacts the refrigerant on the jacket side throughout the process, eliminating the risk of weld leakage and substrate corrosion. The entire process is coherent and controllable, and the finished polymerization reactor has stable heat exchange, long anti-corrosion life, and excellent welding sealing performance, making it suitable for long-term continuous polymerization production of PVC seed micro-suspension paste resin.

[0025] 3) In an optional embodiment, the thickness specifications of the stainless steel base layer and the roughness of the stainless steel inner wall are as follows: a zirconium layer thickness of 1.5 to 2.0 mm can ensure a complete anti-corrosion barrier, and a stainless steel base layer of 4.0 to 6.0 mm provides sufficient structural strength; the inner cavity stainless steel Ra≤0.1μm has a low roughness, which reduces PVC latex adhesion, reduces the frequency of cleaning the inside of the reactor, and reduces cross-contamination between product batches.

[0026] 4) In an optional embodiment, after the zirconium layer is partially milled off at the welding point, a flow guide plate is welded on the stainless steel base layer. A nickel transition layer is used to isolate the weld, avoiding the direct fusion of the carbon steel flow guide plate and the zirconium layer to form a brittle phase. The weld has high strength and no risk of leakage. The nickel transition layer isolates the interdiffusion of steel and zirconium elements. After the milled groove is filled with zirconium welding, the complete zirconium anti-corrosion layer in the jacket is not damaged. The refrigerant only contacts the zirconium layer, and the anti-corrosion performance is not affected by the assembly welding.

[0027] 5) In an optional embodiment, the width, pitch, and chamfer parameters of the guide vane are optimized to further optimize the refrigerant flow velocity and turbulence, thereby further improving the heat exchange efficiency. At the same time, the chamfer of the guide vane reduces the refrigerant flow resistance and reduces the energy consumption of the circulating cooling pump. Attached Figure Description

[0028] Figure 1 This is an overall flow chart of the PVC seed micro-suspension paste resin production equipment.

[0029] Figure 2 yes Figure 1 A magnified view of the area on the left.

[0030] Figure 3 yes Figure 1 A magnified view on the right.

[0031] Figure 4 This is a cross-sectional view of the polymerization reactor.

[0032] Figure 5This is a schematic diagram of the polymerization reactor.

[0033] Figure 6 These are enlarged views of a portion of the side wall of the polymerization reactor. In view a, it is a cross-sectional view of the side wall of the polymerization reactor, and in view b, it is an enlarged view of point I in view a.

[0034] In the picture,

[0035] Raw material and chemical preparation unit:

[0036] A1. VCM storage tank, A2. Hot demineralized water tank, A3. Initiator tank, A4. First emulsifier tank, A5. Second emulsifier tank, A6. Third emulsifier tank, A7. Fourth emulsifier tank, A8. Ammonia tank;

[0037] Polymerization reactor unit:

[0038] B1. Polymerization reactor, B2. Reactor top condenser, B3. First discharge pump, B4. Circulating cooling pump, B5. Seed tank, B6. Seed pump, B7. Initiator pump, B8. First emulsifier pump, B9. Second emulsifier pump, B10. Third emulsifier pump, B11. Fourth emulsifier pump, B12. Buffer pump, B13. Ammonia pump, B14. Raw material VCM pump, B15. Hot water tank pump, B16. Buffer tank, B17. Emergency termination agent tank;

[0039] External gap degassing unit:

[0040] C1. Intermittent stripping tank; C2. Intermittent foam collecting slurry tank; C3. Multi-layer disc mechanical defoamer; C4. Foam collecting tank; C5. Second discharge pump; C6. Slurry intermediate tank;

[0041] Vacuum falling film degassing unit:

[0042] D1. Stripping feed pump; D2. First spiral plate heat exchanger; D3. Vacuum spray falling film tower; D4. Third discharge pump; D5. Second spiral plate heat exchanger; D6. Vacuum falling film mechanical distribution stripping tower; D7. Slurry circulation pump; D8. Third spiral plate heat exchanger; D9. Slurry discharge pump; D10. Drying slurry tank; D11. Vibration filter.

[0043] B101. Polymerization reactor body; B102. Internal cooling pipe; B103. Internal cooling pipe outlet; B104. Internal cooling pipe inlet; B105. Baffle plate; B106. Thermometer transmitter; B107. Inner jacket inlet; B108. Polymerization reactor outlet; B109. Polymerization reactor support leg; B110. Polymerization reactor inlet; B111. Reducer; B112. Motor; B113. Inner jacket outlet; B114. Stainless steel base layer; B115. Zirconium cladding.

[0044] W. The outer wall of the cauldron;

[0045] H. Inner composite panel. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0047] Overall structure of the device:

[0048] like Figures 1-3 As shown, the PVC seed micro-suspension paste resin production device in this embodiment comprises four main units: raw material and chemical preparation unit, polymerization reactor unit, external intermittent degassing unit, and vacuum falling film degassing unit. Figure 1 VCM in this context represents polyethylene monomer. 1.1. Raw Material and Chemical Preparation Unit:

[0049] It includes a VCM storage tank A1, a hot demineralized water tank A2, an initiator tank A3, a first emulsifier tank A4, a second emulsifier tank A5, a third emulsifier tank A6, a fourth emulsifier tank A7, and an ammonia tank A8. Each storage tank independently stores production raw materials and additives, and is equipped with a transfer pump to quantitatively deliver materials to the polymerization reactor.

[0050] 1.2. Polymerization reactor unit:

[0051] The core equipment is the polymerization reactor B1. The reactor sidewall adopts an inner jacket composite plate structure. The outer side is a carbon steel reactor outer wall W, and the inner side is an inner composite plate H. The two together form a sealed jacket gap layer, in which the refrigerant circulates. Spiral guide plates B105 are arranged in the jacket gap.

[0052] Combination Figure 5 and Figure 6 It should be noted that the spiral-shaped guide plate B105 can play the role of spiral flow guidance, but the spiral shape cannot be shown in the cross-sectional view.

[0053] See also Figure 6 The inner composite plate is formed by explosive welding and mechanical rolling of a 316L stainless steel base layer (B114) and a Zr702 zirconium cladding layer (B115). The zirconium cladding layer faces the jacket refrigerant side, and the stainless steel base layer faces the material side of the inner cavity of the reactor.

[0054] The zirconium cladding is 1.8 mm thick, and the stainless steel base layer is 5 mm thick; the inner cavity is mirror polished with stainless steel and the roughness Ra≤0.1μm.

[0055] The deflector is made of Q345R material, with a thickness of 1.8mm, a pitch of 2.5mm, and 20° chamfers on both sides. The processing technology for the welding points of the deflector and the inner composite plate is as follows: the local zirconium layer is milled off to expose the stainless steel base, and then the deflector is welded. A nickel transition layer is deposited on the weld to isolate the steel and zirconium substrate. Then, zirconium welding material is used to fill the milled area. After grinding, the zirconium layer surface is complete and continuous, and the refrigerant only contacts the zirconium layer throughout the process.

[0056] The polymerization reactor unit is equipped with a reactor top condenser B2, a first discharge pump B3, a circulating cooling pump B4, a seed tank B5, various auxiliary agent delivery pumps, a buffer tank B16, an emergency termination agent tank B17, and a wastewater tank, realizing seed latex preparation, continuous addition of auxiliary agents, circulating cooling, emergency termination, and wastewater collection.

[0057] Combination Figure 5 The refrigerant is introduced into the jacket gap through the inlet B107 of the inner jacket of the polymerization reactor. Under the guidance of the spiral guide plate B105, it flows evenly along the spiral channel, fully exchanging heat with the Zr702 metallic zirconium coating of the inner composite plate. The refrigerant after heat exchange is discharged through the outlet B113 of the inner jacket. The spiral guide structure eliminates the heat exchange dead zone in the jacket. With the one-in-one-out circulation path of B107 and B113, it realizes uniform heat exchange around the reactor body, which greatly reduces the temperature fluctuation of the reactor wall during the polymerization process. At the same time, the zirconium coating isolates the chloride ions of the refrigerant, taking into account both the temperature control accuracy and the long-term anti-corrosion performance of the jacket.

[0058] 1.3. External intermittent degassing unit:

[0059] It includes an intermittent stripping tank (C1), an intermittent foam collection slurry tank (C2), a multi-layer disc mechanical defoamer (C3), a foam collection tank (C4), a second discharge pump (C5), and an intermediate slurry tank (C6). After polymerization, the latex is fed into the intermittent stripping tank for initial VCM removal. The foamed material enters the disc defoamer to break up the foam. The foam collection tank recovers the entrained slurry. After degassing, the slurry is temporarily stored in the intermediate slurry tank.

[0060] 1.4. Vacuum Falling Film Degassing Unit

[0061] It consists of a stripping feed pump D1, a first spiral plate heat exchanger D2, a second spiral plate heat exchanger D5, a third spiral plate heat exchanger D8, a vacuum spray falling film tower D3, a vacuum falling film mechanical distribution stripping tower D6, a slurry circulation pump D7, a vibration filter D11, and a drying slurry tank D10. After being heated by the heat exchangers, the slurry first enters the spray falling film tower for pre-stripping, and then is sent to the mechanical falling film stripping tower with a rotary distributor for deep removal of residual VCM. After filtration, it is sent to the drying slurry tank to await drying.

[0062] Material connection relationships of the entire set of equipment: The polymerization reactor B1 is connected to each raw material storage tank, wastewater tank and multi-layer disc mechanical defoamer C3 respectively; the defoamer is connected to the interstitial stripping tank C1 and the interstitial foam capturing slurry tank C2; the interstitial foam capturing slurry tank C2 is transported to the vacuum falling film mechanical distribution stripping tower D6; the vacuum falling film mechanical distribution stripping tower D6 is finally connected to the drying slurry tank D10; the vacuum falling film mechanical distribution stripping tower D6 is connected to the heat exchange pipeline of the first spiral plate heat exchanger D2 to achieve circulating heating.

[0063] Processing and manufacturing method of polymerization reactor B1 (focusing on the appendix) Figure 6 ):

[0064] S1. Weld the stainless steel base layer B114 and the zirconium cladding layer B115 into a whole using explosive welding.

[0065] S2. Rolling to produce an integrated composite plate with a stainless steel base layer B114 and a zirconium cladding layer B115.

[0066] S3. Roll the integrated composite panel into a cylinder;

[0067] S4. Partially mill away the zirconium layer at each welding point on the zirconium surface of the cylinder to expose the internal stainless steel base layer B114.

[0068] S5. The guide plate B105 with the spiral structure is fully welded and fixed to the exposed stainless steel base layer B114; the weld bevel is a V-shaped bevel of 60°±5°, such as... Figure 6 As shown in Figure b;

[0069] S6. Assemble the outer wall W of the vessel to form the jacket gap layer. After alignment, weld and fix the outer wall W of the vessel to the guide plate B105.

[0070] S7. After the weld flaw detection is qualified, a nickel transition layer is deposited on the weld surface;

[0071] S8. On the side of the nickel transition layer facing the jacket gap, fill the milled groove with pure zirconium welding material, and after grinding, the zirconium surface is flush with the original zirconium layer of the cylinder.

[0072] S9. Overall flaw detection confirms that the refrigerant contacts the zirconium cladding layer B115, but not the stainless steel base layer B114 or the nickel transition layer.

[0073] This polymerization reactor preparation method effectively overcomes multiple manufacturing challenges, including the composite of zirconium steel and dissimilar metals, the easy generation of brittle phases when directly welding carbon steel guide plates and zirconium cladding, welding damage to the zirconium anti-corrosion surface layer, and corrosion of the substrate by the jacket refrigerant. First, a high-strength metallurgical composite of stainless steel base and zirconium cladding is achieved through explosive welding combined with mechanical rolling, ensuring that the cylinder has both structural pressure-bearing capacity and chloride ion corrosion resistance. Then, the guide plate is welded onto the stainless steel substrate by partially milling off the zirconium layer, with a nickel transition layer to isolate the dissimilar metal interface. Finally, zirconium material is overlaid to restore the complete anti-corrosion surface layer. This method not only firmly fixes the spiral guide plate to optimize the heat exchange uniformity of the jacket refrigerant, but also ensures that only the zirconium layer contacts the refrigerant on the jacket side throughout the process, eliminating the risk of weld leakage and substrate corrosion. The entire process is coherent and controllable, and the finished polymerization reactor has stable heat exchange, long anti-corrosion life, and excellent welding sealing performance, making it suitable for long-term continuous polymerization production of PVC seed micro-suspension paste resin.

[0074] Complete production process of PVC seed micro-suspension paste resin:

[0075] S1 raw material pre-preparation:

[0076] a. The hot demineralized water is heated to 70°C using a U-tube heater and is ready for use.

[0077] b. Each type of emulsifier is added to a dissolving tank and stirred thoroughly to pre-dissolve it;

[0078] c. Prepare ammonia water to a concentration of 18% and pump it into the ammonia water tank for storage;

[0079] d. Dilute the initiator to prepare a 0.8% aqueous solution and store it for later use.

[0080] S2 seed latex polymerization process:

[0081] a. Evacuate the polymerization reactor twice to 18 kPaA, and replace it with nitrogen to 0.1 MPaG in between to completely remove oxygen from the reactor;

[0082] b. Introduce VCM steam to purge the reactor body, and send the purge exhaust gas into the intermittent foam collection slurry tank for recovery;

[0083] c. Add hot desalinated water, emulsifier, ammonia, initiator and VCM monomer to the reactor in sequence, and prepare seed latex by emulsion polymerization at constant temperature. The finished seed latex is pumped to seed tank B5 for storage.

[0084] S3 intermittent stripping in the reactor:

[0085] After the polymerization reaction is completed, the latex is sent to the intermittent stripping tank C1 through the discharge pipeline, where most of the free VCM is removed by low-pressure stripping. After stripping, the slurry is sent to the multi-layer disc mechanical defoamer C3 to break the foam. The VCM tail gas is recovered in a unified manner, and the defoamed slurry is sent to the intermediate slurry tank C6 for temporary storage via the discharge pump.

[0086] S4 Continuous Pre-Stripping:

[0087] The latex in the intermediate tank of the slurry is fed into the first spiral plate heat exchanger D2 by the stripping feed pump D1. After being heated to 62°C, it is sent to the vacuum spray falling film tower D3 to complete the pre-stripping, which initially reduces the residual amount of monomers in the slurry.

[0088] S5 deep continuous steam pipe discharge drying:

[0089] After pre-stripping, the slurry is fed into a spiral plate heat exchanger for secondary heat preservation to 62°C, and then conveyed to the vacuum falling film mechanical distribution stripping tower D6. The rotating falling film distributor evenly disperses the latex onto the inner wall of the tower, significantly increasing the gas-liquid contact area and deeply removing residual VCM. After degassing, the slurry is conveyed by the slurry discharge pump D9 to the vibration filter D11 to filter impurities, and finally sent to the drying slurry tank D10 for drying to obtain the finished PVC seed micro-suspension paste resin.

[0090] Verification of running results:

[0091] Corrosion resistance: The zirconium coating completely isolates the refrigerant containing chloride ions. After 12 months of continuous operation, there is no pitting corrosion or stress corrosion cracking on the side wall of the jacket. Compared with the traditional all-316L stainless steel kettle, the maintenance cycle is extended by 3 times.

[0092] Heat exchange stability: The spiral guide plate inside the jacket forces the refrigerant to flow in a spiral pattern, eliminating heat exchange dead zones. The polymerization temperature fluctuation inside the reactor is ≤ ±0.2℃, with no local overheating. The finished latex has a narrow particle size distribution and stable paste viscosity.

[0093] Welding reliability: The baffle plate adopts a process of partial milling of zirconium, nickel transition layer, and zirconium sealing welding, which ensures no leakage during continuous operation and that the jacketed refrigerant only comes into contact with the zirconium anti-corrosion layer.

[0094] Production continuity: Four-level unit linkage, intermittent stripping combined with multi-stage continuous vacuum falling film stripping. The reference slurry has a pre-steam content of 10,000-15,000 ppm of vinyl chloride, and after stripping, it is 2,000 ppm. In this embodiment, it can reach 70-100 ppm. 70 / 15,000=0.00467, and the unrecovered percentage is 0.5%. Therefore, the VCM monomer recovery rate is increased to 99.5%, the material transfer loss is greatly reduced, and there is no foam overflow polluting the site.

[0095] This invention solves two major technical challenges—corrosion protection and heat transfer enhancement—simultaneously through the structural design of a composite plate in the inner jacket of a polymerization reactor. The composite plate is formed by explosive welding and mechanical rolling of zirconium metal and stainless steel. The zirconium metal surface contacts the chloride-containing cooling side, fundamentally inhibiting pitting and stress corrosion cracking, significantly extending the operating cycle of the polymerization reactor. The stainless steel surface contacts the material side, with a roughness controlled to Ra≤0.1μm, ensuring material compatibility and the anti-adhesion performance of the inner wall. Simultaneously, the spiral guide plate welded at the gap of the inner jacket effectively improves the removal efficiency of reaction heat and temperature control accuracy by optimizing the cooling medium flow channel, providing a reliable foundation for the uniformity of the polymerization reaction.

[0096] Furthermore, the process design of stepwise temperature control and gradual stripping effectively improves the uniformity of product quality. In each stage of external stripping, continuous pre-stripping, and continuous stripping, the latex is precisely heated and its temperature is stably controlled via a spiral plate heat exchanger, avoiding latex demulsification or wall adhesion caused by localized overheating. The rotating falling film distributor evenly distributes the latex onto the stripping tower wall, increasing the gas-liquid contact area and enhancing VCM removal. The coupling of this process route and equipment structure results in a more uniform particle size distribution of the PVC seed micro-suspended paste resin and a significant improvement in paste viscosity stability, meeting the high-quality production requirements for long-cycle industrial operation.

[0097] The above are preferred embodiments of the present invention. Those skilled in the art can make various modifications or improvements based on these embodiments. Without departing from the overall concept of the present invention, such modifications or improvements should fall within the scope of protection claimed by the present invention.

Claims

1. A polymerization reactor for producing PVC seed micro-suspension paste resin, characterized in that: The sidewall of the polymerization reactor (B1) is an inner jacketed composite plate; The inner jacket composite plate includes an outer outer wall of the vessel (W) and an inner inner composite plate (H), with a jacket gap layer formed between the two. The inner composite plate (H) includes a stainless steel base layer (B114) and a zirconium cladding (B115), the zirconium cladding (B115) being adjacent to the jacket gap layer, and the stainless steel base layer (B114) being adjacent to the inner cavity of the polymerization reactor (B1). The jacket gap layer serves as a channel for refrigerant flow and contains a spiral guide plate (B105).

2. The polymerization reactor for producing PVC seed micro-suspension paste resin as described in claim 1, characterized in that: The zirconium cladding (B115) uses Zr702 zirconium with a thickness of 1.5–2.0 mm, and the stainless steel base layer (B114) uses 316L stainless steel with a thickness of 4.0–6.0 mm; furthermore, the stainless steel surface roughness R… a ≤0.1μm.

3. The polymerization reactor for producing PVC seed micro-suspension paste resin as described in claim 1, characterized in that: The inner composite plate (H) is made of stainless steel and zirconium metal through explosive welding and mechanical rolling processes and then rolled. A small piece of zirconium layer is milled off at the welding point between the inner composite plate (H) and the guide plate (B105) so that the guide plate (B105) can be welded to the exposed stainless steel base layer (B114). A protective layer is formed at the welding point by transition layer nickel welding.

4. The polymerization reactor for producing PVC seed micro-suspension paste resin as described in claim 1, characterized in that: The guide plate (B105) has a width of 1.5 to 2 mm, a pitch of 2.0 to 3.0 mm, and a chamfer of 15° to 30°.

5. A method for manufacturing a polymerization reactor for producing PVC seed micro-suspension paste resin according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Weld the stainless steel base layer (B114) and the metallic zirconium cladding (B115) into a single unit using explosive welding; S2. Rolling to produce an integral composite plate with a stainless steel base (B114) and a zirconium cladding (B115); S3. Roll the integrated composite plate into a cylinder; S4. At each welding point on the zirconium surface of the cylinder, the zirconium layer is partially milled away to expose the internal stainless steel base layer (B114). S5. The guide plate (B105) with the spiral structure is fully welded to the exposed stainless steel base layer (B114); S6. Assemble the outer wall (W) of the vessel to form the jacket gap layer, and weld and fix the outer wall (W) of the vessel to the guide plate (B105) after alignment; S7. After the weld flaw detection is qualified, a nickel transition layer is deposited on the weld surface; S8. On the side of the nickel transition layer facing the jacket gap, fill the milled groove with pure zirconium welding material, and after grinding, the zirconium surface is flush with the original zirconium layer of the cylinder. S9. Overall flaw detection confirms that the refrigerant contacts the zirconium cladding (B115), but not the stainless steel base layer (B114) or the nickel transition layer.

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