Efficient dispersion heat removal system

Abstract

The utility model relates to an efficient dispersion heat removal system which comprises a polymerization reaction device provided with a stirring mechanism, the polymerization reaction device is connected with a first reactant supply unit, a second reactant supply unit, a product post-processing unit and an external circulation heat exchange unit, and the bottom of the polymerization reaction device is connected with an inert gas supply unit. Inert gas provided by the inert gas supply unit is introduced from the bottom of the polymerization reaction device in a bubbling manner. Compared with the prior art, the inert gas is introduced into the bottom of the polymerization reaction device, so that the turbulivity of the reaction material is increased, the material fully flows, the gas carrying heat moves from bottom to top and is moved out of the reactor along with the circulating reflux unit, and efficient dispersion and heat removal are realized.

Description

Technical Field

[0001] The utility model relates to the field of new materials, and particularly relates to an efficient dispersion heat removal system. Background Art

[0002] Polyolefins are a general term for a class of thermoplastic resins obtained by homopolymerization or copolymerization of α-olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene, and certain cycloolefins. Timely removal of reaction heat during the polyolefin production process is a key process to ensure the smooth progress of polymerization. Various heat removal means are disclosed in the prior art. For example, Chinese Patent CN114832736A discloses a heat removal method for polyethylene elastomer polymerization, in which propane liquid is introduced into the reaction glue solution, and the polymerization reaction heat is carried away by the endothermic heating and gasification of propane. However, this method requires subsequent separation of propane from ethylene and other components, with a cumbersome process and high cost. Chinese Patent CN 110918018 A discloses a combined heat removal method for a stirred slurry polyethylene reactor, which discloses the removal of polymerization reaction heat through a combination of solvent evaporation, slurry external circulation, and a reaction kettle jacket, and the use of cooled non-condensable gas returned to the bottom of the reaction kettle. Although this method realizes the heat removal of the polyethylene reactor through a combination of multiple heat removal methods, its system structure is complex, with high cost, high energy consumption, and potential disadvantages in terms of operation and maintenance. How to provide an efficient dispersion heat removal system for timely and efficiently removing reaction heat still requires further research. Summary of the Utility Model

[0003] The purpose of the utility model is to provide an efficient dispersion heat removal system to solve the above problems.

[0004] The purpose of the utility model is achieved through the following technical solutions:

[0005] An efficient dispersion heat removal system includes a polymerization reaction device provided with a stirring mechanism. The polymerization reaction device is connected to a first reactant supply unit, a second reactant supply unit, a product post-treatment unit, and an external circulation heat exchange unit. The bottom of the polymerization reaction device is connected to an inert gas supply unit, and the inert gas provided by the inert gas supply unit is introduced into the bottom of the polymerization reaction device in a bubbling manner.

[0006] As a preferred technical solution of the utility model, the polymerization reaction device is a vertical stirred reaction kettle with a high length-to-diameter ratio. Further preferably, the polymerization reaction device adopts a vertical stirred reaction kettle with a length-to-diameter ratio of 3 to 6. The reaction kettle with a high length-to-diameter ratio increases the residence time of the material in the reaction kettle, which is beneficial to the mixing and reaction between the reaction substances. When the gas material transfers from the bottom to the upper part, it helps to dissipate heat and improve the heat transfer effect in the reaction kettle.

[0007] As a preferred technical solution of the utility model, the external circulation heat exchange unit includes a heat exchange mechanism, a pumping mechanism and a regulating valve arranged in the pipeline. A part of the reaction product is sent to the post-processing unit, and a part of the reaction product flows back to the polymerization reaction device after passing through the external circulation heat exchange unit.

[0008] As a preferred technical solution of the utility model, the inert gas supply unit is connected to the bottom of the polymerization reaction device through a pipeline, and at least one pipe with a plurality of through holes is connected to the end of the pipeline.

[0009] As a preferred technical solution of the utility model, the pipeline with multiple through holes adopts a gas guide rod or a circular ring tube with holes.

[0010] As a preferred technical solution of the utility model, a plurality of baffles are arranged on the inner wall of the polymerization reaction device, and the baffles are irregularly and vertically installed on the inner wall of the polymerization reaction device from top to bottom. The baffles play a certain blocking role on the reaction materials in the reactor. When the stirring mechanism stirs, the flowing liquid will hit each baffle, be divided and rebounded by the baffles, improve the mixing effect of the fluid, avoid the generation of dead zones, which is very helpful for mixing the reactants and improving the uniformity of the reactor.

[0011] As a preferred technical solution of the utility model, the first reactant supply unit or the second reactant supply unit is used to provide gaseous monomer raw materials, which are connected to the polymerization reaction device through a feed pipe. Preferably, the feed pipe is arranged in the form of an annular distribution pipe, and openings are arranged on the annular distribution pipe. More preferably, a feed distributor is installed at the discharge end of the reactant supply unit, for example, a gas distributor is used, so that the gaseous raw materials can enter the reactor in a uniformly dispersed state to avoid explosion and greatly improve the stability of the reaction.

[0012] Compared with the prior art, the utility model has the following beneficial effects:

[0013] The utility model introduces an inert gas (such as nitrogen) at the bottom of the polymerization reaction device, increases the turbulence of the reaction materials through the gas bubbling effect, and makes the materials in the polymerization reaction device flow fully. The gas moves from bottom to top with a large amount of heat and moves out of the polymerization reaction device. Part of the refluxed materials are heat exchanged through an external circulation reflux unit, and part of the materials after the heat is removed are refluxed into the polymerization reaction device to maintain the balanced operation of the system. Baffles are added to the inner wall of the polymerization reaction device, and the baffles play a certain blocking role on each material. When the stirring mechanism stirs, the flowing reaction materials hit each baffle, are divided and rebounded by the baffles, and the mixing effect of the fluid is improved, and the dead zone is avoided. It is very helpful to mix the reactants and improve the uniformity of the reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the overall structural schematic diagram of the heat removal system of the present utility model;

[0015] Figure 2 This is the structural schematic diagram of the gas guiding rod;

[0016] Figure 3 This is the structural schematic diagram of the annular distribution pipe;

[0017] In the figure: 1 - polymerization reaction device; 2 - first reactant supply unit; 3 - inert gas supply unit; 4 - stirring mechanism; 5 - baffle; 6 - product post-treatment unit; 7 - heat exchange mechanism; 8 - second reactant supply unit; 9 - pumping mechanism; 10 - gas spray head; 11 - gas distributor. Specific embodiments

[0018] The present utility model will be described in detail below. Those parts of the present utility model not described in detail are all publicly known technical solutions in the art.

[0019] Referring to Figure 1 , the present utility model provides an efficient dispersion heat removal system to solve the problem of low heat removal efficiency in the production process of polyolefins (especially high molecular weight polyethylene). The heat removal system includes a polymerization reaction device 1 for polymerization. In this embodiment, a vertical reaction kettle is specifically used. The reaction kettle is connected to the first reactant supply unit 2, the second reactant supply unit 8, the product post-treatment unit 6, and an external circulation heat exchange unit through pipelines. The external circulation heat exchange unit includes a heat exchange mechanism 7, a pumping mechanism 9, and various regulating valves arranged in the pipelines. A stirring mechanism 4 is arranged in the reaction kettle. The raw materials required for the reaction are fed into the reaction kettle and then undergo a polymerization reaction. The reaction products are discharged from the discharge port at the upper part of the reaction kettle. Part of the reaction materials are sent to the product post-treatment unit 6 for further treatment to form the final product, and the other part of the reaction materials return to the reaction kettle after passing through the external circulation heat exchange unit.

[0020] In this embodiment, an inert gas supply unit 3 is connected to the bottom of the reaction kettle. It introduces inert gas (preferably nitrogen) into the reaction kettle from the bottom through a ventilation pipe. After the gas with a certain pressure and flow rate enters the reaction kettle slurry in a bubbling manner, it moves upward from bottom to top, increasing the dispersion and turbulence of each reaction material in the reactor, enabling the reaction materials to react fully. At the same time, in combination with the stirring mechanism 4, each reaction material in the reaction kettle is quickly dispersed. A large amount of gas carries a large amount of heat and moves upward from bottom to top. The reaction heat is transferred in a timely manner, dispersed along the axis of the reaction kettle, and finally removed from the reactor with the reaction materials through the discharge port. And part of the reflux materials are heat-exchanged through an external circulation reflux unit. After the heat is removed, this part of the materials returns to the polymerization reaction device to maintain the balanced operation of the system.

[0021] As a preferred embodiment of the utility model, the inert gas supply unit 3 is connected to the bottom of the reactor through a pipeline, and a plurality of pipes with a plurality of through holes are connected to the end of the pipeline. The pipe with through holes can be a short long pipe, for example, a gas guide rod (such as Figure 2 As shown in the figure, according to specific needs, multiple gas guide rods can be provided, so that the gas can be more evenly introduced into the reactor to better disperse the materials. As a further preferred embodiment, a gas nozzle 10 can also be installed at the end of the pipeline. For example, a compressed air nozzle can be used to allow the gas to enter the reactor with a certain impact force, thereby accelerating the material dispersion rate.

[0022] As a preferred embodiment of the present invention, the polymerization reaction device 1 of the present invention adopts a reactor with a high aspect ratio. Preferably, the reactor adopts an aspect ratio of 3 to 6, for example, a reactor with an aspect ratio of 5. The reactor with a high aspect ratio allows the gas to have a longer path in the process of rising inside, increases the contact time between the gas and the reaction materials, makes the reaction materials more fully mixed and reacted, and promotes the reaction. When the gas moves from bottom to top with a large amount of heat, the contact area with the reaction materials increases in the process of passing through the reactor with a high aspect ratio, and the heat is more easily transferred, making the temperature in the reactor more uniform, which helps to evenly distribute the heat and improve the heat transfer effect in the reactor.

[0023] As a preferred implementation scheme of the utility model, a plurality of baffles 5 are arranged on the inner wall of the reactor of the utility model. The baffles 5 are irregularly and vertically installed on the inner wall of the reactor from top to bottom. The baffles 5 have a certain blocking effect on the reaction materials in the reactor. When the stirring mechanism 4 stirs, the flowing liquid will hit each baffle 5, be divided and rebounded by the baffle 5, thereby improving the mixing effect of the fluid and avoiding the generation of dead zones. This is very helpful for mixing the reactants and improving the uniformity of the reactor.

[0024] As a preferred embodiment of the present invention, the feed pipe of the first reactant supply unit 2 is arranged in the form of an annular distribution pipe (such as Figure 3 As shown), and holes are arranged on the annular distribution pipe. Further preferably, the feed pipe of the first reactant supply unit can be provided with a feed distributor, such as a gas distributor 11, so that the gas raw material can enter the reactor in a uniformly dispersed state, avoiding the occurrence of implosion and improving the stability of the reaction.

[0025] As a preferred implementation scheme of the utility model, the stirring mechanism 4 can preferably adopt a plate-and-frame agitator, which can greatly improve the reaction efficiency by utilizing the excellent heat transfer and mass transfer effects of the plate-and-frame agitator, and reduce the problems of uneven stirring, easy sedimentation, uneven heat dissipation, etc. in the polymerization process.

[0026] When producing ultra-high molecular weight polyethylene by the continuous slurry process using the above system, the specific process is as follows: The first reactant supply unit 2 supplies raw materials including ethylene, butene, hydrogen, etc., and the second reactant supply unit 8 supplies a solvent including hexane and a catalyst, etc. They are continuously fed through their respective feed ports. The inert gas supply unit 3 continuously feeds nitrogen from the bottom. Each material is stirred and dispersed in the reaction kettle under the action of the stirring mechanism 4 for polymerization. During this process, nitrogen with a certain pressure and flow rate moves upward from the bottom, quickly dispersing the reaction materials in the reaction kettle, and transferring the reaction heat to the upper part of the reaction kettle in a timely manner. Finally, the product is discharged from the discharge port, and a large amount of heat is removed from the reactor. An external circulation heat exchange unit is arranged outside the reaction kettle for heat exchange, and a part of the heat-exchanged liquid is refluxed into the reactor to maintain the material stability and heat stability of the reaction system. In addition, the setting of the baffle 5 in the reactor greatly improves the mixing and dispersion effect of the fluid, which helps to improve the homogeneity of the reactants.

[0027] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the utility model. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present utility model is not limited to the above embodiments, and all improvements and modifications made by those skilled in the art without departing from the scope of the present utility model according to the disclosure of the present utility model should be within the protection scope of the present utility model.

Claims

1. An efficient decentralized heat removal system, characterized in that: The invention comprises a polymerization reaction device provided with a stirring mechanism, wherein the polymerization reaction device is connected with a first reactant supply unit, a second reactant supply unit, a product post-processing unit and an external circulation heat exchange unit, and the bottom of the polymerization reaction device is connected with an inert gas supply unit, and the inert gas provided by the inert gas supply unit is introduced into the bottom of the polymerization reaction device in a bubbling manner.

2. A highly efficient dispersed heat removal system according to claim 1, characterized in that: The polymerization reaction device is a vertical stirring reactor with a high aspect ratio.

3. A highly efficient dispersed heat removal system according to claim 2, characterized in that: The polymerization reaction device adopts a vertical stirring reactor with a length-to-diameter ratio of 3-6.

4. The highly efficient dispersed heat removal system according to claim 1, characterized in that: The external circulation heat exchange unit includes a heat exchange mechanism, a pumping mechanism and a regulating valve arranged in a pipeline. A part of the reaction product is sent to the post-processing unit, and a part of the reaction product is refluxed to the polymerization reaction device after passing through the external circulation heat exchange unit.

5. The highly efficient dispersed heat removal system according to claim 1, characterized in that: The inert gas supply unit is connected to the bottom of the polymerization reaction device through a pipeline, and at least one pipe with a plurality of through holes is connected to the end of the pipeline.

6. The high-efficiency dispersed heat removal system according to claim 5, characterized in that: The pipeline with multiple through holes adopts a gas guide rod or a circular ring tube with holes.

7. The highly efficient dispersed heat removal system according to claim 1, characterized in that: A plurality of baffles are arranged on the inner wall of the polymerization reaction device, and the baffles are irregularly and vertically installed on the inner wall of the polymerization reaction device from top to bottom.

8. The highly efficient dispersed heat removal system according to claim 1, characterized in that: The first reactant supply unit or the second reactant supply unit is used to provide raw materials including gaseous monomers and is connected to the polymerization reaction device through a feed pipe.

9. The high-efficiency dispersed heat removal system according to claim 8, characterized in that: The feed pipe is arranged in the form of an annular distribution pipe, and openings are arranged on the annular distribution pipe.

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