A reaction kettle for solvent separation in synthetic resin

Abstract

The novel synthesis resin solvent separation reaction kettle disclosed by the application comprises a reaction kettle body, the reaction kettle body comprises a cylinder body, upper and lower heads are arranged on the upper and lower sides of the cylinder body respectively, a reaction kettle valve is arranged on the lower head, the reaction kettle valve is connected with a gear pump through a circulating pipe, the gear pump is communicated with a falling film coil horizontally arranged in the cylinder body through the circulating pipe, a plurality of holes are arranged on the bottom of the falling film coil and are uniformly distributed in a ring shape around the center of the falling film coil, and a stirring device is arranged below the falling film coil. By increasing the falling film circulating coil, when the gear pump is started, the acrylic resin in the reaction kettle is pumped into the falling film coil and flows out from the lower holes of the falling film coil in a "filamentous" form to fall on the liquid surface in the kettle. This process greatly increases the mass transfer area of the acrylic resin, so that the contained solvent is accelerated to transfer to the gas phase through the "filamentous" surface vacuum, and then condensed into liquid through the horizontal condenser and flows into the collecting tank, thereby improving the solvent separation effect.

Description

Technical Field

[0001] This utility model relates to the technical field of fine chemical process production, and in particular to a reaction vessel for solvent separation in synthetic resins. Background Technology

[0002] One method for polymerizing acrylic resins, which facilitates reduced viscosity, rapid mass transfer, and heat transfer, typically involves adding a non-reactive solvent during synthesis; this is known as "solution polymerization." The process is characterized by the following steps: the solvent is first added to a reactor and heated to a set temperature; then, acrylate monomers (including styrene) and an initiator are simultaneously and uniformly added dropwise to the reactor according to the formulation ratio, resulting in an acrylic resin solution containing 30-50% solvent.

[0003] After polymerizing an acrylic resin solution containing solvent, the solvent needs to be separated from the resin solution as required. Conventional methods involve lowering the solvent's boiling point by creating a vacuum in the reactor under specified temperature conditions to increase the speed and efficiency of solvent removal. However, during vacuum solvent removal, as the solid content and viscosity of the acrylic resin solution increase, the resin's flow characteristics deteriorate. The turbulence of the resin within the reactor, aided by stirring, gradually reduces the mass transfer and descaling effect at the interface. Simultaneously, van der Waals forces increase the difficulty of solvent escaping from the resin solution. When more than 90% of the solvent is removed by vacuum, it is difficult to separate the solvent from the resin without increasing the temperature. However, increasing the temperature will alter the molecular structure of the acrylic resin. For example, acrylic resins containing both hydroxyl and carboxyl groups may react to form esters and gel at temperatures exceeding a set point. Therefore, developing equipment that effectively improves solvent separation is of practical significance. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a reaction vessel that improves solvent separation efficiency.

[0005] This utility model discloses a reaction vessel for solvent separation in synthetic resins, comprising a reaction vessel body, the reaction vessel body including a cylindrical body, an upper end cap and a lower end cap respectively provided on the upper and lower sides of the cylindrical body, a reaction vessel valve provided on the lower end cap, the reaction vessel valve being connected to a gear pump through a circulation pipe, the gear pump being connected to a falling film coil horizontally arranged inside the cylindrical body through a circulation pipe, the bottom of the falling film coil being provided with a plurality of openings evenly distributed in a ring around the center of the falling film coil, and a stirring device being provided below the falling film coil.

[0006] According to some embodiments of the present invention, the ratio of the inner diameter of the cylinder to the height of the cylinder is 1:1.1 to 1:1.5.

[0007] According to some embodiments of this utility model, the stirring device is a frame-type stirring device.

[0008] According to some embodiments of this utility model, the width of the frame mixer is 0.5 to 0.6 times the inner diameter of the cylinder, and the height is 0.45 to 0.55 times the inner diameter of the cylinder.

[0009] According to some embodiments of this utility model, the frame of the frame mixer is made of rectangular steel plate.

[0010] According to some embodiments of the present invention, the frame-type stirrer includes left and right side frames, which are connected by upper and lower plates. The left and right side frames are rotated 45° toward the pot wall, and the upper and lower plates are rotated 45° toward the bottom of the pot.

[0011] According to some embodiments of this utility model, the diameter of the falling film coil is 0.5 to 0.6 times the inner diameter of the cylinder.

[0012] According to some embodiments of this utility model, the opening on the falling film coil is an elongated ellipse.

[0013] According to some embodiments of this utility model, a reactor sight glass is provided on the upper end cap.

[0014] According to some embodiments of this utility model, the circulation pipe is a circulation pipe sleeve into which a heat-conducting medium can be injected.

[0015] This invention has at least the following beneficial effects: By adding a falling film circulation coil, when the gear pump is started, the acrylic resin in the reactor is drawn into the falling film coil inside the reactor and flows out in a "filamentous" manner from the opening at the bottom of the falling film coil onto the liquid surface inside the reactor. This process greatly increases the mass transfer area of ​​the acrylic resin, allowing the solvent contained therein to be transferred to the gas phase through the vacuum of the "filamentous" surface. After being condensed into liquid by the horizontal condenser, it flows into the collection tank, thereby improving the solvent separation effect.

[0016] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0018] Figure 1 A process flow diagram for preparing solvent-containing resins;

[0019] Figure 2 This is a schematic diagram of the reactor structure of this utility model;

[0020] Figure 3This is a schematic diagram of the falling film coil structure of this utility model;

[0021] Figure 4 This is a schematic diagram of the falling film coil installation structure of this utility model. Detailed Implementation

[0022] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0023] In the description of this utility model, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0024] In the description of this utility model, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features or their sequential relationship.

[0025] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0026] Reference Figure 1 Specifically, the process for preparing a solvent-containing acrylic resin solution is divided into four stages.

[0027] Phase 1: Synthesis of acrylic resin solution containing solvent.

[0028] 11. After metering through the initiator solvent metering tank V1, add the formulated amount of solvent into the reactor F and stir.

[0029] 12. After metering the acrylic monomer into the acrylic monomer metering tank V2, add the formulated amount of acrylate monomer (including styrene) and stir.

[0030] 13. After metering the solvent and initiator into the initiator solvent metering tank V1, add the prescribed amount of solvent and initiator, and stir.

[0031] 14. After heating the solvent in reactor F to the temperature specified in the process, simultaneously add acrylate monomers (including styrene) from acrylate monomer metering tank V2 and initiator solvent metering tank V1 dropwise according to the time specified in the process. After the acrylate monomers (including styrene) and initiator are added, maintain the temperature according to the time specified in the process.

[0032] 15. After the insulation is completed, add the additional initiator prepared according to the formula at the time specified in the process;

[0033] 16. After dripping, keep warm for the time specified in the process;

[0034] 17. In the above process, the solvent in reactor F may be in a reflux state (i.e., the temperature in reactor F is raised to the boiling point of the solvent, the vapor rises and is cooled and condensed into liquid by the horizontal condenser G and then enters the water separator V3, and then returns to reactor F through the U-shaped tube H of the water separator), or it may be in a non-reflux state (i.e., reactor F is not heated to the boiling point of the solvent).

[0035] Phase Two: Vacuum Separation of Solvents Using Conventional Processes

[0036] 21. Open the three-way valve at the bottom of the water separator V3 and the valve on the gas phase balance pipe E1. Drain the solvent in the water separator V3 into the solvent collection tank V4. Open the bottom valve of the solvent collection tank V4 to drain the solvent from the water separator V3, then close it. Open the vacuum valve B of the solvent collection tank V4 to remove the solvent from the acrylic resin in the reactor F;

[0037] 22. When most of the solvent is separated at the temperature specified in the process and it is difficult to continue separating the solvent as observed by the sight glass of the reactor and the solvent collection tank V4, i.e., it is impossible to continue separating the solvent, a third stage is adopted to continue separating the solvent.

[0038] Third stage: Using a circulating falling film coil to increase the mass transfer area and continue separating the solvent in the acrylate solution.

[0039] 31. Maintain a constant temperature inside reactor F. Open valve B1 at the bottom of reactor F, adjust the three-way valve 2 at the bottom of reactor F to the direction of gear pump 4, open valve B2 to enter reactor, open heating valve B3 of circulating pipe sleeve, and start circulating gear pump 2. Through sight glass 7, you can see that the resin flowing downward from the hole of falling film coil 5 inside the reactor falls to the surface of acrylic resin liquid in the form of "filamentous" falling film. The load sensor of solvent collection tank V4 can show the amount of separated solvent.

[0040] 32. Keep the circulation pump running until the solvent collection tank V4 is basically free of solvent, then stop the circulation pump.

[0041] Phase 4: Waterborne Resin Waterborneization

[0042] 41. Prepare the required amount of deionized water containing the neutralizing agent in the dilution vessel R, and start stirring;

[0043] 42. Open the three-way valve at the bottom of reactor F to the direction of entering diluent R, and at the same time open the valve on the gas phase balance pipe E2. Slowly add the desolventized acrylic resin into diluent R. Then, add other raw materials according to the acrylic resin formula. For example, when preparing an aqueous acrylic resin solution, first add a neutralizing agent to neutralize it before adding other raw materials to obtain aqueous acrylic resin.

[0044] Reference Figure 2 A reaction vessel for solvent separation in synthetic resins includes a reaction vessel body 1, which includes a cylindrical body 11. An upper end cap 12 and a lower end cap 13 are respectively provided on the upper and lower sides of the cylindrical body 11. A reaction vessel valve 2 is provided on the lower end cap 13. The reaction vessel valve 2 is a three-way valve. The reaction vessel valve 2 is connected to a gear pump 4 via a circulation pipe 3. The gear pump 4 is connected to a falling film coil 5 horizontally arranged inside the cylindrical body 11 via the circulation pipe 3. The bottom of the falling film coil 5 has several openings 51 evenly distributed in a ring around the center of the falling film coil 5. (Refer to...) Figure 3 The opening on the falling film coil 5 is an elongated ellipse with a size of 3×8mm, and a stirring device 6 is installed below the falling film coil 5. For easy observation, a reactor sight glass 7 is installed on the upper end cap 12.

[0045] When selecting a gear pump 4, it is essential to first test the viscosity of the solvent-free resin at the desolventizing temperature. Then, the viscosity and required flow rate should be used as key criteria for selecting the gear pump. Ideally, the flow rate of the gear pump 4 should ensure that the material circulation time within the reactor is less than 15 minutes for one cycle, thus effectively meeting the descaling efficiency requirements.

[0046] To prevent the acrylic resin solution from increasing in viscosity due to a drop in temperature during circulation in the circulation pipes 3 before and after the gear pump 4, the circulation pipes 3 before and after the gear pump 4 are sleeves into which a heat-conducting medium can be injected. The sleeves are heated to the same temperature as the reactor using a heating medium. To ensure deglossing, the resin flow rate in the circulation pipes 3 is <1.5 m / s. Based on this condition, the flow rate of the gear pump 4 is selected as the radius of the falling film coil 5 × 3.14 × 3600 × 1.5.

[0047] The reactor body 1 is configured such that the ratio of the inner diameter to the height of the cylinder 11 is 1:1.1 to 1:1.5. When the ratio of the inner diameter to the height of the cylinder 11 is less than 1:1.1, the stirring power required is high, especially in the later stage of delustering, which is not suitable.

[0048] The stirring device 6 is a frame-type stirrer. The width of the frame-type stirrer is 0.5 to 0.6 times the inner diameter of the cylinder, and the height is 0.45 to 0.55 times the inner diameter of the cylinder. The frame of the frame-type stirrer is made of rectangular steel plate. The frame-type stirrer includes left and right frames, which are connected by upper and lower plates. The left and right frames are rotated 45° towards the vessel wall, and the upper and lower plates are rotated 45° towards the bottom of the vessel. This design allows the resin solution to exhibit both a thrown-to-the-vessel-wall and an upward-swirling state during the stirring and rotation process.

[0049] In its design, the falling film coil 5 has a diameter that is 0.5 to 0.6 times the inner diameter of the cylinder. The falling film coil 5 is installed at the weld of the upper end cap 12. (Refer to...) Figure 4 During installation, three L-shaped hanging brackets 8 are installed inward from the upper end cap 12. The hanging brackets 8 are clamped to the falling film coil 5 by pipe clamps 81. This design maximizes the distance that the resin solution travels from the coil pores to the liquid surface, thereby increasing the mass transfer area.

[0050] The reactor body 1 is equipped with an outer half-pipe or jacket 14 for injecting a heat-conducting medium. Depending on the characteristics of the heating medium, if it is a non-phase-change liquid heating medium (such as heat transfer oil), it enters the outer half-pipe through the bottom valve and flows out through the upper valve, with the cooling medium flowing in and out in the same direction. If it is a phase-change heating medium (such as steam-condensate), it enters through the upper valve of the outer half-pipe and flows out as condensate through the lower valve, with the cooling water flowing in and out in the same direction.

[0051] During the circulation and vacuuming process of gear pump 4, the acrylic resin solution flows out in a "filamentous" manner from falling film coil 5 to the liquid surface inside the reactor. The height between the falling film coil 5 and the deglossed resin liquid surface inside the reactor body 1 is greater than or equal to 1.5 meters.

[0052] As the solvent is removed from the reactor F under vacuum, the content of non-volatile components and the viscosity of the solvent gradually increase. When more than 95% of the solvent in the acrylic resin solution is removed under vacuum, solvent removal without increasing the temperature becomes very difficult. At this point, gear pump 4 is started to pump the acrylic resin from the reactor into the falling film coil 5 inside the reactor, and it flows out in a "filamentous" manner from the opening 51 at the bottom of the falling film coil 5 onto the liquid surface inside the reactor. This process greatly increases the mass transfer area of ​​the acrylic resin, allowing the contained solvent to be rapidly transferred to the gas phase through the vacuum of the "filamentous" surface. After being condensed into liquid by the horizontal condenser G, it flows into the collection tank V4, reducing the solvent content in the acrylic resin. When the solvent collection tank V4 can no longer collect solvent during the operation of gear pump 4, gear pump 4 can be turned off.

[0053] The preferred embodiments of this utility model have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of this utility model without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of this utility model through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A reaction vessel for solvent separation in synthetic resins, characterized in that, The reactor includes a reactor body (1), which includes a cylinder (11). The upper and lower sides of the cylinder (11) are respectively provided with an upper end cap (12) and a lower end cap (13). The lower end cap (13) is provided with a reactor valve (2). The reactor valve (2) is connected to a gear pump (4) through a circulation pipe (3). The gear pump (4) is connected to a falling film coil (5) located horizontally inside the cylinder (11) through the circulation pipe (3). The bottom of the falling film coil (5) is provided with a number of openings (51) evenly distributed in a ring around the center of the falling film coil (5). A stirring device (6) is provided below the falling film coil (5).

2. The reaction vessel for solvent separation in synthetic resins according to claim 1, characterized in that, The ratio of the inner diameter to the height of the cylinder (11) is 1:1.1 to 1:1.

5.

3. The reaction vessel for solvent separation in synthetic resins according to claim 1, characterized in that, The stirring device (6) is a frame-type stirring device.

4. A reaction vessel for solvent separation in synthetic resins according to claim 3, characterized in that, The width of the frame mixer is 0.5 to 0.6 times the inner diameter of the cylinder, and the height is 0.45 to 0.55 times the inner diameter of the cylinder.

5. A reaction vessel for solvent separation in synthetic resins according to claim 3, characterized in that, The frame of the frame mixer is made of rectangular steel plate.

6. A reaction vessel for solvent separation in synthetic resins according to claim 3, characterized in that, The frame-type stirrer includes left and right side frames, which are connected by upper and lower plates. The left and right side frames are rotated 45° towards the vessel wall, and the upper and lower plates are rotated 45° towards the bottom of the vessel.

7. A reaction vessel for solvent separation in synthetic resins according to claim 1, characterized in that, The diameter of the falling film coil (5) is 0.5 to 0.6 times the inner diameter of the cylinder.

8. A reaction vessel for solvent separation in synthetic resins according to claim 1, characterized in that, The opening on the falling film coil (5) is an elongated ellipse.

9. A reaction vessel for solvent separation in synthetic resins according to claim 1, characterized in that, The upper head (12) is provided with a reactor sight glass (7).

10. A reaction vessel for solvent separation in synthetic resins according to claim 1, characterized in that, The circulation pipe (3) is a circulation pipe sleeve into which a heat-conducting medium can be injected.

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