A vertical condensation reflux equipment for solution polymerization reactor

Abstract

The utility model discloses a kind of vertical condensation reflux equipment for solution type polymerization reactor, it includes upper section, lower section, upper section is vertical fixed tube plate type heat exchanger, lower section includes cylinder, heat transfer assembly is equipped in cylinder;Upper section condenser heat exchange pipe, upper section condenser baffle are equipped in vertical fixed tube plate type heat exchanger, the lower part of vertical fixed tube plate type heat exchanger is equipped with upper section condenser refrigerant inlet, and the upper part is equipped with upper section condenser refrigerant outlet;The heat transfer assembly includes gas distributor located below, liquid distributor located above, and filler layer is equipped between gas distributor and liquid distributor by filler.This utility model can improve heat transfer efficiency and reduce energy consumption, improve condensing efficiency, realize monomer recovery rate ≥95%, reflux temperature difference ≤5 ℃, reduce the influence of solvent reflux temperature difference on polymerization process, realize temperature difference control.

Description

Technical Field

[0001] This utility model relates to a vertical condenser reflux device for a solution polymerization reactor, specifically a vertical condenser reflux device suitable for solution polymerization reactors of polymer monomers such as acrylate (optical adhesive), styrene (resin), and vinyl chloride (plastic), belonging to the field of chemical equipment technology. Background Technology

[0002] Solution polymerization is widely used in the coatings, adhesives, and synthetic fiber industries due to its advantages such as easy diffusion of polymerization heat and easy product transport. This type of reaction requires the use of low-boiling-point solvents (such as ethyl acetate (boiling point 77℃) and toluene (boiling point 110.6℃). During the reaction, the solvent and 10%-15% of the monomer will evaporate to form a gas phase. If this is not recovered in time, it can lead to: 1. Material waste and pollution: Traditional equipment has a single-unit loss rate of 5%-10%, with annual loss costs exceeding 100,000 yuan (taking a 500L reactor as an example), and unrecovered solvents require additional treatment, increasing environmental protection costs; 2. Low condensation efficiency: In the traditional "vertical condenser + horizontal condenser" combination, the vertical condenser is mostly a vertical tube structure welded as a whole, resulting in insufficient contact between the gas phase and the condensation surface, and the solvent recovery rate is only 85%-90%; the condensate in the secondary horizontal condenser is directly refluxed, and the temperature difference between it and the material in the reactor (80-120℃) reaches 20-30℃, which leads to a sudden drop in local reaction temperature and a 3%-5% reduction in polymerization conversion rate; 3. Space and maintenance issues: Horizontal condensers require horizontal layout, and the overall equipment occupies 30% more floor space than vertical integrated structures; welded structures cannot be disassembled, and after material residues (especially polymers) solidify, high-pressure cleaning is required, and the heat exchange efficiency decreases by more than 15% after 3-6 months.

[0003] It is evident that existing technologies have not solved the synergistic problem of "efficient contact condensation, temperature difference control, and easy maintenance". Summary of the Invention

[0004] The technical problem to be solved by this utility model is to provide a condensation reflux device for solution polymerization reactors that can efficiently recover low-boiling-point solvent vapors (such as ethyl acetate and toluene) evaporated during the reaction, reduce material loss and stabilize the polymerization reaction temperature, and is suitable for the limited space layout requirements of small and medium-sized workshops.

[0005] To address the aforementioned problems, this utility model provides a vertical condenser reflux device for a solution-type polymerization reactor, comprising an upper section and a lower section. The upper section is a vertical fixed tube sheet heat exchanger (material flows through the tubes, refrigerant flows through the shell), and the lower section includes a cylindrical body containing heat transfer components. The vertical fixed tube sheet heat exchanger contains upper condenser heat exchange tubes and upper condenser baffles. The lower part of the vertical fixed tube sheet heat exchanger has an upper condenser refrigerant inlet, and the upper part has an upper condenser refrigerant outlet. The heat transfer components include a gas distributor located below and a liquid distributor located above, with a packing layer composed of packing material between the gas distributor and the liquid distributor. The equipment is made of stainless steel (304 / 316L), titanium alloy (TA2), Hastelloy (C276), or enamel. When processing chlorine-containing / acidic materials, titanium alloy or Hastelloy is preferred.

[0006] Preferably, the upper section has a top connecting flange for the upper condenser at the top and a bottom connecting flange for the upper condenser at the bottom; the lower section has a top connecting flange for the lower condenser at the top and a bottom connecting flange for the lower condenser at the bottom.

[0007] More preferably, a gasket is provided between the bottom connecting flange of the upper condenser and the top connecting flange of the lower condenser. The gasket is made of polytetrafluoroethylene or graphite and is suitable for temperatures from -20°C to 200°C to prevent gas phase leakage.

[0008] Preferably, the vertical fixed tube sheet heat exchanger is provided with 2-4 arc-shaped upper condenser baffles, which are connected to the inner wall of the shell side. The spacing between adjacent upper condenser baffles is 1-1.5 times the diameter of the vertical fixed tube sheet heat exchanger, which is used to guide the flow of refrigerant in the shell side and improve the heat exchange uniformity.

[0009] Preferably, the bottom of the upper section is equipped with a shell-side drain outlet with a shut-off valve for draining residual refrigerant from the shell side of the equipment, facilitating maintenance and preventing freezing and cracking in winter. The tube-side (material channel) diameter of the vertical fixed tube sheet heat exchanger matches the gas phase inlet of the reactor (usually 200-300mm), with 20-40 heat exchange tubes (20-30mm in diameter) to ensure a reasonable gas phase flow velocity (0.5-1m / s); the shell-side (refrigerant channel) is equipped with an arc-shaped baffle to avoid refrigerant short-circuiting, improving heat exchange efficiency by 20%.

[0010] Preferably, the upper part of the cylinder is provided with a return port for connecting the condensate return pipe of the secondary condenser above the liquid distributor.

[0011] Preferably, the gas distributor is a porous sieve plate structure with pore diameters of 5-15 mm and an open area ratio of 30-50%, used to uniformly disperse the gas phase from the reactor into the packing layer; the packing is corrugated packing or stepped ring packing with a specific surface area of ​​200-500 m². 2 / m 3 The height of the packing layer is 0.5-1.5m, which is used to increase the gas-liquid contact area.

[0012] Preferably, the liquid distributor is a trough-type distributor with a bottom distribution hole spacing of 20-50mm, used to evenly spray the condensate onto the top of the packing layer.

[0013] Preferably, a jacket is provided outside the cylinder at a position between the liquid distributor and the gas distributor, with a jacket refrigerant inlet at the lower part and a jacket refrigerant outlet at the upper part.

[0014] More preferably, the specific parameters for the next section are as follows: The cylinder diameter is the same as the upper section (to ensure smooth gas flow), the jacket thickness is 8-12mm, and cooling water is introduced to assist in cooling, making it suitable for high-load reaction scenarios; Gas distributor: The porous sieve plate disperses the gas phase into small bubbles, preventing the gas phase from concentrating and impacting the packing, increasing the contact area by 40%; Packing layer: 304 stainless steel corrugated packing (specific surface area 350m²) is selected. 2 / m 3 The gas phase and condensate form a "liquid film contact" on the packing surface, increasing the monomer capture rate by 10%. Liquid distributor: The trough structure "sprays" the condensate evenly, avoiding dry areas in the filler and ensuring uniform contact.

[0015] More preferably, the vertical condensation reflux equipment also includes an intelligent control module, which includes a flow sensor and a pneumatic regulating valve installed on the refrigerant pipeline in the shell side and jacket of the vertical fixed tube sheet heat exchanger, and a PLC controller that receives signals; the controller automatically adjusts the refrigerant flow rate according to the gas phase temperature of the reactor (obtained by an external temperature sensor) to achieve precise control of condensation efficiency.

[0016] During operation, the condenser reflux port is connected to the condensate reflux pipe at the outlet of the secondary condenser. The solvent condensed above the vertical heat exchanger and the solvent condensed from the secondary condenser are fully contacted in a counter-current manner with the gaseous solvent from the reactor, which has been uniformly dispersed by the gas distributor, through the liquid distributor and packing. The condensate from the secondary condenser (temperature 50-60℃) is introduced into the liquid distributor, mixed with the reflux condensate from the upper section (temperature 80-85℃), and then sprayed onto the packing layer. It is preheated to 85-88℃ by the gas phase (90-95℃) inside the reactor, thereby significantly improving heat transfer efficiency, reducing energy consumption, improving condensation efficiency, achieving a monomer recovery rate of ≥95%, a reflux temperature difference of ≤5℃, reducing the impact of solvent reflux temperature difference on the polymerization process, and achieving temperature difference control. This utility model adopts a vertical structure, reducing the floor space by 30%, and the flange connection facilitates cleaning. It can also automatically adjust the refrigerant flow through an intelligent control module, reducing cooling water consumption by 25%.

[0017] This invention is applicable to vapor recovery in the solution polymerization reaction of polymers such as acrylates and styrene, and has the advantages of energy saving, stability and easy maintenance. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of the vertical condenser reflux device for the solution polymerization reactor provided by this utility model.

[0019] Figure 1 In the middle section, 1-top connecting flange of upper condenser, 2-baffle plate of upper condenser, 3-heat exchange tube of upper condenser, 4-refrigerant inlet of upper condenser, 5-refrigerant outlet of upper condenser, 6-shell drain outlet of upper condenser, 7-bottom connecting flange of upper condenser, 8-top connecting flange of lower condenser, 9-liquid distributor, 10-packing, 11-gas distributor, 12-bottom connecting flange of lower condenser, 13-jacket, 14-refrigerant inlet of jacket, 15-refrigerant outlet of jacket, 16-return port. Detailed Implementation

[0020] To make this utility model more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0021] like Figure 1As shown, this utility model provides a vertical condenser reflux device for a solution-type polymerization reactor, comprising an upper section, a lower section, and an intelligent control module. The upper section is a vertical fixed tube sheet heat exchanger, and the lower section includes a cylinder containing heat transfer components. The upper section has a top connecting flange 1 for the upper condenser and a bottom connecting flange 7 for the upper condenser at the bottom. The lower section has a top connecting flange 8 for the lower condenser and a bottom connecting flange 12 for the lower condenser at the bottom. A gasket, made of polytetrafluoroethylene (PTFE) or graphite, is provided between the bottom connecting flange 7 and the top connecting flange 8 of the lower condenser.

[0022] The vertical fixed tube sheet heat exchanger includes upper condenser heat exchange tubes 3 and upper condenser baffles 2. The lower part of the vertical fixed tube sheet heat exchanger has an upper condenser refrigerant inlet 4, and the upper part has an upper condenser refrigerant outlet 5. The vertical fixed tube sheet heat exchanger contains 2-4 arc-shaped upper condenser baffles 2, which are connected to the shell-side inner wall. The spacing between adjacent upper condenser baffles 2 is 1-1.5 times the diameter of the vertical fixed tube sheet heat exchanger. The bottom of the upper section has an upper condenser shell-side drain outlet 6 with a shut-off valve. Above the liquid distributor 9, the upper part of the cylinder has a reflux port 16 for connecting the condensate reflux pipe to the secondary condenser.

[0023] The heat transfer assembly includes a lower gas distributor 11 and an upper liquid distributor 9, with a packing layer of packing material 10 between the gas distributor 11 and the liquid distributor 9. A jacket 13 is located outside the cylinder relative to the space between the liquid distributor 9 and the gas distributor 11. The jacket 13 has a refrigerant inlet 14 at its lower part and a refrigerant outlet 15 at its upper part. The gas distributor 11 has a porous sieve plate structure with holes of 5-15 mm in diameter and an open area ratio of 30-50%. The packing material 10 is corrugated packing or stepped ring packing with a specific surface area of ​​200-500 m². 2 / m 3 The height of the packing layer is 0.5-1.5m. The liquid distributor 9 is a trough-type distributor with a bottom distribution hole spacing of 20-50mm.

[0024] The intelligent control module includes flow sensors and pneumatic regulating valves installed on the shell side and the refrigerant pipeline inside the jacket 13 of the vertical fixed tube sheet heat exchanger, and a PLC controller that receives signals.

[0025] Example 1 Taking the polymerization reaction of 500L acrylate optical adhesive (solvent: ethyl acetate, reaction temperature 90℃) as an example, the main body is made of 316L stainless steel (resistant to weak acids), the gasket is made of polytetrafluoroethylene (temperature resistance from -20℃ to 200℃), and the filler is 316L stainless steel corrugated filler (specific surface area 350m²). 2 / m 3 ): 1. Gas phase generation: In this embodiment, the solution polymerization reaction is an exothermic process. Due to its low boiling point, the ethyl acetate solvent is heated and evaporated to form a gas phase (temperature 90°C) containing acrylate monomers (boiling point 145-155°C), which enters the equipment through the bottom flange 12 of the lower section.

[0026] 2. Single-contact condensation: The gas phase is uniformly dispersed from the reactor by the gas distributor 11 and enters the packing layer upward. It comes into counter-current contact with the material flowing back from the liquid distributor 9 in the packing layer to carry out sufficient heat and mass transfer. This process causes most of the acrylate and other material monomers to be condensed and flow back into the reactor with the liquid.

[0027] 3. Secondary condensation: Uncondensed ethyl acetate vapor continues to rise and enters the upper condenser heat exchange tube 3 of the vertical fixed tube sheet heat exchanger, where it exchanges heat with the shell-side circulating cooling water. More than 90% of it is condensed into liquid and flows back to the liquid distributor 9 along the upper condenser heat exchange tube 3.

[0028] 4. Three-stage condensation and circulation: A small amount of uncondensed solvent enters the secondary horizontal condenser through the top connecting flange 1 of the upper condenser and is completely condensed and recovered. After mixing with the condensate returning from the upper tube heat exchange section through the return port 16, it is redistributed by the liquid distributor 9 and enters the packing layer, where it participates in the packing layer contact again and finally flows back into the reactor, forming a closed-loop circulation.

[0029] The following technical effects are achieved through the above-described workflow in this embodiment: Recovery efficiency: Solvent recovery rate 95%, acrylate monomer loss rate 1%; Temperature difference control: reflux liquid temperature 85-88℃, temperature difference with the inside of the reactor ≤5℃, polymerization conversion rate 98% (93% for traditional equipment); Energy consumption and space: Cooling water consumption is reduced by 25%, and floor space is reduced by 35%; Maintainability: The equipment can be separated by disassembling the bottom connecting flange 7 of the upper condenser and the top connecting flange 8 of the lower condenser. The packing can be removed and cleaned, and there are no residues on the heat exchange tubes.

[0030] Example 2 For processing vinyl chloride polymerization (solvent: dichloroethane, highly corrosive), the main body of the vertical reflux condenser in this embodiment is made of titanium alloy TA2 (resistant to chloride ion corrosion), and the refrigerant is changed to -5℃ chilled brine (suitable for dichloroethane's boiling point of 83.5℃). Depending on the specific reflux solvent and reactants being processed, this equipment can be made of various materials, such as stainless steel, titanium alloy, Hastelloy, enamel, etc.

[0031] The technical effects of this embodiment are: solvent recovery rate of 96%, monomer loss rate ≤0.8%, and no corrosion after 6 months of equipment operation.

Claims

1. A vertical condenser reflux device for a solution-type polymerization reactor, characterized in that, It includes an upper section and a lower section. The upper section is a vertical fixed tube sheet heat exchanger, and the lower section includes a cylinder with heat transfer components inside. The vertical fixed tube sheet heat exchanger is equipped with an upper section condenser heat exchange tube (3) and an upper section condenser baffle (2). The lower part of the vertical fixed tube sheet heat exchanger is equipped with an upper section condenser refrigerant inlet (4), and the upper part is equipped with an upper section condenser refrigerant outlet (5). The heat transfer components include a gas distributor (11) located below and a liquid distributor (9) located above. A packing layer composed of packing (10) is provided between the gas distributor (11) and the liquid distributor (9).

2. The vertical condenser reflux device for a solution-type polymerization reactor as described in claim 1, characterized in that, The upper section is provided with an upper section condenser top connecting flange (1) at the top and an upper section condenser bottom connecting flange (7) at the bottom; the lower section is provided with a lower section condenser top connecting flange (8) at the top and a lower section condenser bottom connecting flange (12) at the bottom.

3. The vertical condenser reflux device for a solution-type polymerization reactor as described in claim 2, characterized in that, A gasket is provided between the bottom connecting flange (7) of the upper condenser and the top connecting flange (8) of the lower condenser. The gasket is made of polytetrafluoroethylene or graphite.

4. The vertical condenser reflux device for a solution-type polymerization reactor as described in claim 1, characterized in that, The vertical fixed tube sheet heat exchanger is provided with 2-4 arc-shaped upper condenser baffles (2), which are connected to the inner wall of the shell side. The spacing between adjacent upper condenser baffles (2) is 1-1.5 times the diameter of the vertical fixed tube sheet heat exchanger.

5. The vertical condenser reflux device for a solution-type polymerization reactor as described in claim 1, characterized in that, The bottom of the upper section is provided with an upper section condenser shell-side drain outlet (6) with a shut-off valve.

6. The vertical condenser reflux device for a solution-type polymerization reactor as described in claim 1, characterized in that, The upper part of the cylinder is provided with a return port (16) above the liquid distributor (9) for connecting the condensate return pipe of the secondary condenser.

7. The vertical condenser reflux device for a solution-type polymerization reactor as described in claim 1, characterized in that, The gas distributor (11) is a porous sieve plate structure with a hole diameter of 5-15 mm and an opening rate of 30-50%; the packing (10) is corrugated packing or stepped ring packing with a specific surface area of ​​200-500 m². 2 / m 3 The height of the filler layer is 0.5-1.5m.

8. The vertical condenser reflux device for a solution-type polymerization reactor as described in claim 1, characterized in that, The liquid distributor (9) is a trough-type distributor with a bottom distribution hole spacing of 20-50mm.

9. The vertical condenser reflux device for a solution-type polymerization reactor as described in any one of claims 1-8, characterized in that, A jacket (13) is provided on the outside of the cylinder relative to the liquid distributor (9) and the gas distributor (11). The lower part of the jacket (13) is provided with a jacket refrigerant inlet (14), and the upper part is provided with a jacket refrigerant outlet (15).

10. The vertical condenser reflux device for a solution-type polymerization reactor as described in claim 9, characterized in that, It also includes an intelligent control module, which includes a flow sensor and a pneumatic regulating valve installed on the refrigerant pipeline in the shell side and jacket (13) of the vertical fixed tube sheet heat exchanger, and a PLC controller that receives signals.

Images