Feed pretreatment apparatus in ultra-high molecular weight polyethylene production

Abstract

The utility model relates to the technical field of ultrahigh molecular weight polyethylene production, specifically to feed pretreatment device in ultrahigh molecular weight polyethylene production. Including desulfurizing tower, carbon monoxide removal tower, oxygen removal tower, polymerization reactor, solid -liquid mixing tank, desulfurizing tower links to each other with carbon monoxide removal tower through the carbon monoxide removal tower, and oxygen removal tower links to each other with polymerization reactor through flow controller, and desulfurizing tower is connected with pressure regulating valve through the pipeline connection of desulfurizing tower, and the pipeline of ethylene is equipped on pressure regulating valve, and the outside of polymerization reactor is equipped with polymerization reactor temperature control cover, and solid -liquid mixing tank links to each other with polymerization reactor through the pipeline. The cooperation of the use of desulfurizing tower, carbon monoxide removal tower, first, the sulfur impurities and carbon monoxide contained in ethylene are removed, and then water vapor and oxygen are removed in oxygen removal tower and dehydration tower, greatly improve the impurity removal rate of ethylene, improve the product quality.

Description

Technical Field

[0001] This utility model relates to the field of ultra-high molecular weight polyethylene (UHMWPE) production technology, specifically to a feed pretreatment device in UHMWPE production. Background Technology

[0002] Ultra-high molecular weight polyethylene (UHMWPE) is a type of polyethylene with extremely high molecular weight. Its molecular weight is typically above 1.5 million, and its molecular chains are significantly longer than those of ordinary polyethylene. While ordinary polyethylene has relatively short molecular chains, the long molecular chains of UHMWPE give it many unique properties. These long chains intertwine, endowing the material with excellent toughness, abrasion resistance, and impact resistance.

[0003] In actual production, the slurry process is often used, where ethylene monomers polymerize in a diluent (such as hexane) under the action of a catalyst to produce UHMWPE. This process requires high ethylene purity. However, existing production equipment has several shortcomings: First, it only uses drying to adsorb moisture from ethylene, without treating impurities such as carbon dioxide, carbon monoxide, and acetylene, thus affecting product quality. Second, when ethylene gas enters the reactor, it enters below the liquid surface. Due to insufficient absorption by hexane, some gas escapes from the liquid phase, and this escaped gas is difficult to react further and requires recovery, significantly reducing production efficiency. Third, the raw materials in the solid-liquid mixing tank are greatly affected by temperature. When the outdoor temperature is low, the temperature also drops. Directly introducing low-temperature raw materials into the reactor will affect the reactor's production efficiency and product quality. Utility Model Content

[0004] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a feed pretreatment device for the production of ultra-high molecular weight polyethylene. By using a desulfurization tower and a carbon monoxide removal tower in combination, sulfur-containing impurities and carbon monoxide contained in ethylene are first removed. Then, water vapor and oxygen are removed in the deoxygenation tower and the dehydration tower, which greatly improves the impurity removal rate of ethylene and improves product quality. By using a pressure regulating valve and a flow controller in combination, the ethylene feed is made more stable.

[0005] This utility model is achieved using the following technical solution:

[0006] The feed pretreatment device for ultra-high molecular weight polyethylene production includes a desulfurization tower, a carbon monoxide removal tower, a deoxidation tower, a polymerization reactor, and a solid-liquid mixing tank. The desulfurization tower is connected to the deoxidation tower via the carbon monoxide removal tower. The deoxidation tower is connected to the polymerization reactor via a flow controller. The desulfurization tower is connected to a pressure regulating valve via an inlet pipe. An ethylene inlet pipe is installed on the pressure regulating valve. A temperature control jacket for the polymerization reactor is installed on the outside of the polymerization reactor. The solid-liquid mixing tank is connected to the polymerization reactor via a pipe.

[0007] A dehydration tower is provided between the deoxygenation tower and the flow controller. A dehydration tower outlet pipe is connected between the dehydration tower and the flow controller. An inlet pipe is connected between the carbon monoxide removal tower and the deoxygenation tower.

[0008] The polymerization reactor is equipped with a stirring paddle driven by a stirring motor.

[0009] The polymerization reactor is connected to a vacuum pump via a pipe, and a blower is connected to the polymerization reactor via a nitrogen pipe that extends into the interior of the polymerization reactor.

[0010] The temperature control jacket outside the polymerization reactor precisely controls the reaction temperature, providing a suitable temperature environment for the polymerization reaction. Inside, a stirring paddle driven by a stirring motor is installed. The stirring shaft has upper and lower vents, which are connected by the stirring shaft, allowing gas to pass freely. During stirring, this promotes the dispersion and absorption of ethylene gas in hexane. The gas phase dispersion port is connected to a flow controller via a gas phase inlet pipe, ensuring that ethylene gas is evenly dispersed into the reactor, allowing for sufficient contact with the catalyst, improving reaction efficiency and product quality. A blower connected via a nitrogen pipeline maintains a stable reaction environment, and a vacuum pump can be connected to regulate the pressure inside the reactor.

[0011] The solid-liquid mixing tank is connected to a catalyst inlet pipe, and the outside of the solid-liquid mixing tank is equipped with a mixing tank insulation sleeve. The solid-liquid mixing tank is also connected to a hexane inlet pipe.

[0012] The temperature control jacket of the polymerization reactor is connected to the insulation jacket of the mixing tank via a connecting pipe, and a liquid storage valve is provided at the bottom of the solid-liquid mixing tank.

[0013] The stirring motor and the stirring paddle are connected by a stirring shaft. The stirring shaft is provided with an upper vent and a lower vent. The upper vent is located above the stirring paddle, and the lower vent is located below the stirring paddle.

[0014] The polymerization reactor is equipped with a gas phase dispersion port inside. A flow controller is connected to the gas phase dispersion port through a gas phase inlet pipe. The gas phase dispersion port is equipped with an outlet, which is located on the side away from the agitator.

[0015] The working principle of this utility model is as follows:

[0016] Ethylene gas containing impurities enters the pipeline via an ethylene inlet. After the pressure is regulated by a pressure regulating valve, it enters the desulfurization tower through the inlet pipeline to remove sulfur impurities. It then flows sequentially through a carbon monoxide removal tower, a deoxygenation tower, and a dehydration tower to remove impurities such as carbon monoxide, oxygen, and moisture, respectively. The ethylene gas treated in the dehydration tower then enters the flow controller through the dehydration tower outlet pipeline. Its feed rate is precisely controlled before it enters the polymerization reactor.

[0017] The solid catalyst is slowly introduced into the solid-liquid mixing tank, using the hexane level to buffer the impact of the falling catalyst and prevent it from breaking or being damaged. Hexane is continuously added to the solid-liquid mixing tank through a hexane inlet pipe, where it mixes with the solid catalyst. An insulation sleeve on the outside of the mixing tank maintains a suitable mixing temperature to ensure uniform mixing.

[0018] Pretreated ethylene gas and a homogeneously mixed catalyst-hexane mixture in a solid-liquid mixing tank undergo polymerization in the polymerization reactor. A temperature control jacket outside the reactor precisely maintains the required reaction temperature. A stirring motor drives the agitator, and upper and lower vents on the stirring shaft promote the dispersion of ethylene gas in the hexane. A gas phase dispersion port is connected to a flow controller via a gas phase inlet pipe, allowing ethylene gas to enter the polymerization reactor uniformly through the outlet. Under the action of the catalyst, it undergoes efficient polymerization to produce ultra-high molecular weight polyethylene. During the reaction, a vacuum pump maintains stable pressure within the polymerization reactor, and a blower introduces nitrogen gas through a nitrogen pipeline to create a stable reaction environment.

[0019] Compared with the prior art, the beneficial effects of this utility model are:

[0020] (1) The feed pretreatment device in the production of ultra-high molecular weight polyethylene of this utility model is used in combination with the desulfurization tower and the carbon monoxide removal tower to remove sulfur-containing impurities and carbon monoxide contained in ethylene. Then, water vapor and oxygen are removed in the deoxygenation tower and the dehydration tower, which greatly improves the impurity removal rate of ethylene and improves the product quality. The use of pressure regulating valve and flow controller makes the ethylene feed more stable.

[0021] (2) The stirring shaft in the polymerization reactor is equipped with an upper vent and a lower vent. During the rotation of the stirring shaft, the gas can be absorbed from the top and discharged from the bottom, which promotes the dispersion and absorption of ethylene gas in hexane, reduces the situation of gas escaping from the liquid phase, and thus improves production efficiency.

[0022] (3) The temperature control jacket of the polymerization reactor and the insulation jacket of the mixing tank are connected by connecting pipes, which can realize the rational utilization and transfer of heat, help maintain the temperature conditions required for polymerization reaction and mixing process, ensure the stability and consistency of reaction, and reduce the impact of ambient temperature on production. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the feeding pretreatment device in the production of ultra-high molecular weight polyethylene according to this utility model;

[0024] Figure 2 This is a schematic diagram of the polymerization reactor of this utility model;

[0025] In the diagram: 1. Desulfurization tower; 2. Carbon monoxide removal tower; 3. Deoxygenation tower; 4. Polymerization reactor; 5. Catalyst inlet pipe; 6. Solid-liquid mixing tank; 7. Pressure regulating valve; 8. Flow controller; 9. Dehydration tower; 10. Dehydration tower outlet pipe; 11. Desulfurization tower inlet pipe; 12. Stirring motor; 13. Deoxygenation tower inlet pipe; 14. Stirring paddle; 15. Blower; 16. Vacuum pump; 17. Nitrogen pipe; 18. Gas phase inlet pipe; 19. Hexane inlet pipe; 20. Mixing tank insulation sleeve; 21. Polymerization reactor temperature control sleeve; 22. Connecting pipe; 23. Liquid storage valve; 24. Stirring shaft; 25. Upper vent; 26. Lower vent; 27. Gas phase dispersion port; 28. Gas outlet. Detailed Implementation

[0026] To make the objectives and technical solutions of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings.

[0027] Example 1

[0028] like Figure 1 As shown, the feed pretreatment device in the production of ultra-high molecular weight polyethylene includes a desulfurization tower 1, a carbon monoxide removal tower 2, a deoxidation tower 3, a polymerization reactor 4, and a solid-liquid mixing tank 6. The desulfurization tower 1 is connected to the deoxidation tower 3 via the carbon monoxide removal tower 2. The deoxidation tower 3 is connected to the polymerization reactor 4 via a flow controller 8. The desulfurization tower 1 is connected to a pressure regulating valve 7 via an inlet pipe 11, and an ethylene inlet pipe is installed on the pressure regulating valve 7. A polymerization reactor temperature control sleeve 21 is installed on the outside of the polymerization reactor 4. The solid-liquid mixing tank 6 is connected to the polymerization reactor 4 via a pipe. A dehydration tower 9 is located between the deoxidation tower 3 and the flow controller 8, and an outlet pipe 10 connects the dehydration tower 9 to the flow controller 8. An inlet pipe 13 connects the carbon monoxide removal tower 2 and the deoxidation tower 3. The polymerization reactor 4 is equipped with a stirring paddle 14 driven by a stirring motor 12 inside, and a polymerization reactor temperature control sleeve 21 is installed on the outside of the polymerization reactor 4. A vacuum pump 16 is connected to the polymerization reactor 4 via a pipeline, and a blower 15 is connected to the polymerization reactor 4 via a nitrogen pipeline 17 extending into the reactor 4. A catalyst inlet pipeline 5 is connected to the solid-liquid mixing tank 6, and a mixing tank insulation sleeve 20 is installed on the outside of the tank. A hexane inlet pipeline 19 is also connected to the solid-liquid mixing tank 6. The polymerization reactor temperature control sleeve 21 is connected to the mixing tank insulation sleeve 20 via a connecting pipeline 22, and a liquid storage valve 23 is located at the bottom of the solid-liquid mixing tank 6. The solid-liquid mixing tank 6 is used to mix the solid-phase catalyst and hexane. The outer mixing tank insulation sleeve 20 maintains a suitable mixing temperature, promoting uniform mixing and preparing for subsequent reactions within the polymerization reactor. The liquid storage valve 23 at its bottom facilitates control of the outflow of the mixture. Figure 2As shown, a stirring shaft 24 connects the stirring motor 12 and the stirring paddle 14. The stirring shaft 24 has an upper vent 25 and a lower vent 26. The upper vent 25 is located above the stirring paddle 14, and the lower vent 26 is located below the stirring paddle 14. The polymerization reactor 4 has a gas phase dispersion port 27 inside. The flow controller 8 is connected to the gas phase dispersion port 27 through a gas phase inlet pipe 18. The gas phase dispersion port 27 has an outlet 28, which is located on the side away from the stirring paddle 14.

[0029] The above-mentioned feed pretreatment device in the production of ultra-high molecular weight polyethylene includes the following steps during operation:

[0030] (1) Ethylene gas containing impurities enters the ethylene inlet pipeline. After the pressure is adjusted by the pressure regulating valve 7, it enters the desulfurization tower 1 through the desulfurization tower inlet pipeline 11 to remove sulfur impurities. Then it flows through the carbon monoxide removal tower 2, deoxygenation tower 3, and dehydration tower 9 in sequence to remove impurities such as carbon monoxide, oxygen, and moisture. The ethylene gas treated by the dehydration tower 9 enters the flow controller 8 through the dehydration tower outlet pipeline 10. After its feed rate is precisely controlled, it enters the polymerization reactor 4. (2) The solid catalyst is slowly introduced into the solid-liquid mixing tank 6. The hexane level is used to buffer the impact of the catalyst falling, so as to avoid the catalyst being broken or damaged by the impact. Hexane is continuously added to the solid-liquid mixing tank 6 through the hexane inlet pipeline 19 and mixed with the solid catalyst in the tank. The mixing tank insulation sleeve 20 on the outside of the solid-liquid mixing tank 6 maintains a suitable mixing temperature to ensure that the two are mixed evenly. (3) The pretreated ethylene gas and the catalyst-hexane mixture that is mixed evenly in the solid-liquid mixing tank 6 undergo a polymerization reaction in the polymerization reactor 4. The temperature control sleeve 21 outside the polymerization reactor 4 precisely maintains the required reaction temperature. The stirring motor 12 drives the stirring paddle 14 to rotate, and the upper vent 25 and lower vent 26 on the stirring shaft 24 promote the dispersion of ethylene gas in hexane. The gas phase dispersion port 27 is connected to the flow controller 8 through the gas phase inlet pipe 18. Ethylene gas enters the polymerization reactor 4 uniformly through the outlet 28 on the gas phase dispersion port 27, where it undergoes a highly efficient polymerization reaction under the action of the catalyst to produce ultra-high molecular weight polyethylene. During the reaction, the pressure inside the polymerization reactor 4 can be maintained stable by the vacuum pump 16, and nitrogen gas is introduced into the polymerization reactor 4 through the nitrogen pipe 17 using the blower 15 to create a stable reaction environment.

Claims

1. A feed pretreatment device for ultra-high molecular weight polyethylene production, characterized in that, The system includes a desulfurization tower (1), a carbon monoxide removal tower (2), a deoxygenation tower (3), a polymerization reactor (4), and a solid-liquid mixing tank (6). The desulfurization tower (1) is connected to the deoxygenation tower (3) through the carbon monoxide removal tower (2). The deoxygenation tower (3) is connected to the polymerization reactor (4) through a flow controller (8). The desulfurization tower (1) is connected to a pressure regulating valve (7) through an inlet pipe (11). An ethylene inlet pipe is provided on the pressure regulating valve (7). A polymerization reactor temperature control sleeve (21) is provided on the outside of the polymerization reactor (4). The solid-liquid mixing tank (6) is connected to the polymerization reactor (4) through a pipe. The polymerization reactor (4) is equipped with a stirring paddle (14) driven by a stirring motor (12). The solid-liquid mixing tank (6) is connected to a catalyst inlet pipe (5), and the outside of the solid-liquid mixing tank (6) is provided with a mixing tank insulation sleeve (20). The solid-liquid mixing tank (6) is connected to a hexane inlet pipe (19). The temperature control sleeve (21) of the polymerization reactor is connected to the insulation sleeve (20) of the mixing tank through the connecting pipe (22), and the solid-liquid mixing tank (6) is provided with a liquid storage valve (23) below it. A stirring shaft (24) is connected between the stirring motor (12) and the stirring paddle (14). The stirring shaft (24) is provided with an upper vent (25) and a lower vent (26). The upper vent (25) is located above the stirring paddle (14), and the lower vent (26) is located below the stirring paddle (14).

2. The feed pretreatment device for ultra-high molecular weight polyethylene production according to claim 1, characterized in that, A dehydration tower (9) is provided between the deoxygenation tower (3) and the flow controller (8). A dehydration tower outlet pipe (10) is connected between the dehydration tower (9) and the flow controller (8). An inlet pipe (13) is connected between the carbon monoxide removal tower (2) and the deoxygenation tower (3).

3. The feed pretreatment device for ultra-high molecular weight polyethylene production according to claim 1, characterized in that, The polymerization reactor (4) is connected to a vacuum pump (16) via a pipe, and the polymerization reactor (4) is connected to a blower (15) via a nitrogen pipe (17), which extends into the interior of the polymerization reactor (4).

4. The feed pretreatment device for ultra-high molecular weight polyethylene production according to claim 1, characterized in that, The polymerization reactor (4) is provided with a gas phase dispersion port (27) inside. The flow controller (8) is connected to the gas phase dispersion port (27) through the gas phase inlet pipe (18). The gas phase dispersion port (27) is provided with an outlet hole (28), which is located on the side away from the stirring paddle (14).

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