Ultrahigh molecular weight polyethylene reaction kettle

Abstract

The utility model provides an ultra-high molecular weight polyethylene reaction kettle, belongs to the technical field of polyethylene production, and solves the problem that in the prior art, the reaction cannot be normally carried out due to the fact that heat is not removed in time. The device comprises a barrel, sealing heads are arranged at the upper end and the lower end of the barrel, an inner clamping sleeve is arranged on the inner wall of the barrel and connected with a water inlet pipe and a water outlet pipe which penetrate through the side wall of the barrel, a finger-shaped inner cooling blocking pipe is vertically arranged in the barrel, and the finger-shaped inner cooling blocking pipe comprises an outer pipe and a finger-shaped rod arranged on the outer wall of the outer pipe. An inner pipe is arranged on the inner side of the outer pipe, and the bottom of the inner pipe communicates with the outer pipe. The inner jacket is arranged on the inner wall of the barrel, so that the phenomenon that the heat transfer efficiency of polyethylene is influenced by too thick wall of the barrel is effectively avoided, and circulating cooling water is introduced into the finger-shaped inner cooling baffle pipe to assist in cooling, so that heat in the production process is timely conveyed out of the reaction kettle, and the reaction can be effectively ensured to be normally carried out at a proper temperature; therefore, polyethylene with ultra-high molecular weight can be produced.

Description

Technical Field

[0001] The utility model belongs to the technical field of polyethylene production, in particular to an ultra-high molecular weight polyethylene reactor. Background Art

[0002] Ultra-high molecular weight polyethylene (molecular weight 1-6 million) is a thermoplastic engineering plastic with excellent comprehensive properties. Common methods for producing ultra-high molecular weight polyethylene include Mitsui low-pressure slurry method, Solvay method, and UCC gas phase method, among which the low-pressure slurry method is the most important method. The low-pressure slurry method is that the gaseous ethylene introduced from the boundary area is depressurized and enters the ethylene preheater, heated by medium-pressure steam and controlled to add the hydrocarbon steam circulation pipeline, and then the ethylene enters the reactor and undergoes polymerization reaction under the action of the catalyst to form a slurry-like substance.

[0003] A large amount of heat will be generated during the above-mentioned polymerization reaction. In order to ensure that the reaction is carried out at a suitable temperature, an external jacket will be set on the outside of the reactor for heat exchange. Due to the low heat transfer coefficient of the external jacket and poor heat exchange effect, it is necessary to use external circulation or add hexane to evaporate and remove the heat. In the production process of ultra-high molecular weight polyethylene, the concentration of slurry and catalyst in the reactor is high, and the hexane heat is not removed in time, the product will swell, explode, agglomerate, and settle. The overflow outlet, external circulation pipeline and heat exchanger will be blocked. At the same time, the catalyst inlet pipe is also easily blocked, making production impossible. Based on the above problems, the existing ultra-high molecular weight polyethylene reactor cannot produce polyethylene with a higher molecular weight (molecular weight 6-10 million), because the production of ultra-high molecular weight polyethylene requires lowering the reaction pressure and reaction temperature, which will prolong the reaction time, causing the catalyst to settle and more easily block the pipeline. Utility Model Content

[0004] In view of the above problems, the purpose of the utility model is to provide an ultra-high molecular weight polyethylene reactor, in which an inner jacket is arranged on the inner wall of the cylinder to effectively prevent the cylinder wall thickness from being too thick and affecting the heat transfer efficiency of the polyethylene, and circulating cooling water is introduced into the finger-shaped internal cooling pipe to assist in cooling, so that the heat in the production process can be transported out of the reactor in time, which can effectively ensure that the reaction proceeds normally at a suitable temperature, thereby producing ultra-high molecular weight polyethylene.

[0005] The technical solution adopted by the utility model is as follows:

[0006] An ultra-high molecular weight polyethylene reactor comprises a cylinder, wherein both upper and lower ends of the cylinder are provided with heads, an inner jacket is provided on the inner wall of the cylinder, the inner jacket is connected with a water inlet pipe and a water outlet pipe penetrating the side wall of the cylinder, a finger-shaped inner cooling baffle is vertically arranged in the cylinder, the finger-shaped inner cooling baffle comprises an outer tube and a finger-shaped rod arranged on the outer wall of the outer tube, an inner tube is arranged on the inner side of the outer tube, and the bottom of the inner tube is communicated with the outer tube.

[0007] Preferably, the water inlet pipes and the water outlet pipes are provided in multiple groups.

[0008] Preferably, a guide plate is provided in the inner jacket.

[0009] Preferably, half-tube jackets are provided on the outer walls of the two heads.

[0010] Preferably, the cylinder is provided with a downwardly inclined overflow discharge pipe and an upwardly inclined catalyst feed pipe.

[0011] Preferably, the overflow discharge pipe and the catalyst feed pipe are both provided with flushing pipes.

[0012] Preferably, a temperature measuring tube is provided on the cylinder.

[0013] Preferably, a plate-and-frame agitator is arranged in the cylinder, the plate-and-frame agitator is connected to a vertically arranged agitator shaft, the agitator shaft is connected to a agitator transmission device, and the agitator transmission device is installed on the head above the cylinder.

[0014] Preferably, the stirring transmission device includes a frame installed on the head, a motor is installed on the frame, the motor is connected to a reducer, the reducer is connected to a sealing shaft that movably penetrates the head through a coupling I, a mechanical seal is provided on the sealing shaft for sealing the gap between the head and the sealing shaft, and the lower end of the sealing shaft is connected to the stirring shaft through a coupling II.

[0015] Preferably, both of the sealing heads are provided with quick-opening manholes.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the utility model are:

[0017] An inner jacket is set on the inner wall of the cylinder to effectively prevent the cylinder wall thickness from being too thick and affecting the heat transfer efficiency of polyethylene. In addition, circulating cooling water is introduced into the finger-shaped internal cooling pipe for auxiliary cooling, so that the heat in the production process can be transported out of the reactor in time, which can effectively ensure that the reaction proceeds normally at a suitable temperature, thereby producing ultra-high molecular weight polyethylene. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic diagram of a cross-sectional structure provided for an embodiment of the utility model;

[0020] Figure 2 A schematic diagram of the inner jacket structure provided by an embodiment of the utility model;

[0021] Figure 3 A schematic diagram of the finger-shaped internal cooling baffle structure provided in an embodiment of the utility model.

[0022] Description of the drawings: 1-barrel; 2-stirring transmission device; 201-frame; 202-motor; 203-reducer; 204-coupling I; 205-sealing shaft; 206-mechanical seal; 207-coupling II; 3-support; 4-head; 5-semi-pipe jacket; 6-inner jacket; 7-water inlet pipe; 8-water outlet pipe; 9-finger-shaped inner cooling pipe; 901-outer pipe; 902-inner pipe; 903-finger-shaped rod; 10-feed pipe; 11-quick-opening manhole; 12-stirring shaft; 13-flushing pipe; 14-overflow discharge pipe; 15-plate and frame agitator; 16-catalyst feed pipe; 17-temperature measuring tube; 18-discharge port; 19-guide plate. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the description of the present invention, it should be noted that if the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the application is usually placed when used. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0026] Combine the following Figure 1-Figure 3 The utility model is described in detail. Example

[0027] An ultra-high molecular weight polyethylene reactor, such as Figure 1 As shown, it includes a cylinder 1, and the upper and lower ends of the cylinder 1 are provided with a head 4. The inner wall of the cylinder 1 is provided with an inner jacket 6, and the inner jacket 6 is connected with a water inlet pipe 7 and a water outlet pipe 8 that penetrate the side wall of the cylinder 1. A finger-shaped internal cooling pipe 9 is vertically provided in the cylinder 1. Figure 3 As shown, the finger-shaped inner cooling tube 9 includes an outer tube 901 and a finger-shaped rod 903 arranged on the outer wall of the outer tube 901. An inner tube 902 is arranged inside the outer tube 901 and the bottom of the inner tube 902 is connected to the outer tube 901. The inner jacket 6 and the upper and lower heads 4 are smoothly transitioned without changing the stirring flow field.

[0028] The plate thickness of the inner jacket 6 is much smaller than that of the cylinder 1, so the inner jacket 6 is arranged on the inner wall of the cylinder 1, which can improve the efficiency of heat conduction to the inner jacket 6, and the cooling water in the inner jacket 6 can take away the heat in the reactor more quickly. The pipe opening at the upper end of the inner tube 902 is the water inlet, and the outer tube 901 is a pipe with a sealing plate. An outlet is opened on the upper side wall as a water outlet, so that cooling water can be introduced for circulating cooling. The finger-shaped rod 903 can transfer heat to the outer tube 901, thereby increasing the cooling efficiency of the finger-shaped inner cooling baffle 9; the inner jacket 6 cooperates with the finger-shaped inner cooling baffle 9 to increase the heat transfer coefficient of the reactor from 700 kcal / hm of the traditional reactor to 100 kcal / hm. 2 .℃ increased to 1100 kcal / hm 2 .℃, which greatly improves the heat exchange capacity of the reactor and can control the reaction temperature more accurately.

[0029] A support 3 for supporting the entire reactor is provided on the outer wall of the cylinder 1; a feed pipe 10 is provided on the head 4 located above the cylinder 1, and the feed pipe 10 continuously adds materials into the reactor during production; a discharge port 18 is provided on the head 4 located below the cylinder 1, and the discharge port 18 is closed during production. After the production is stopped, the material in the reactor is discharged through the discharge port 18.

[0030] The water inlet pipe 7 and the water outlet pipe 8 are provided in multiple groups, which can reduce the temperature difference between the inlet and outlet water and enhance the heat exchange capacity of the inner jacket 6.

[0031] like Figure 2 As shown, a guide plate 19 is provided in the inner jacket 6. The guide plate 19 is spiral, which facilitates the cooling water to flow evenly in the inner jacket 6. The guide plate 19 can also support the inner jacket 6 and increase the structural strength of the inner jacket 6.

[0032] The outer walls of the two heads 4 are both provided with half-tube jackets 5. The half-tube jackets 5 are also provided with a water inlet and a water outlet. Cooling water is introduced into the half-tube jackets 5 to circulate and absorb the heat at the heads 4, further enhancing the heat exchange capacity of the reactor.

[0033] The cylinder 1 is provided with an overflow discharge pipe 14 inclined downward and a catalyst feed pipe 16 inclined upward. The overflow discharge pipe 14 can continuously discharge the reacted materials during the production process. Since the reactor of the present application is for continuous reaction, the overflow discharge pipe 14 will also be connected to another reactor (not shown in the figure) to prevent the materials output by the feed pipe 10 from flowing out of the overflow discharge pipe 14 before they are completely reacted. The materials discharged by the overflow discharge pipe 14 are reacted again in another reactor to ensure the quality of the product. The catalyst feed pipe 16 adds the catalyst required for the reaction to the reactor.

[0034] The overflow discharge pipe 14 and the catalyst feed pipe 16 are both provided with a flushing pipe 13. The flushing pipe 13 uses hexane as a flushing medium, which evaporates and takes away heat while flushing, thereby preventing the overflow discharge pipe 14 and the catalyst feed pipe 16 from being blocked due to ethylene polymerization.

[0035] The cylinder 1 is provided with a temperature measuring tube 17. The temperature measuring tube 17 is provided with a temperature measuring sensor, which can monitor the temperature inside the reactor and adjust the flow of cooling water at various locations according to the temperature, thereby controlling the amount of heat transfer.

[0036] The cylinder 1 is provided with a plate-frame agitator 15, the plate-frame agitator 15 is connected to a vertically arranged agitator shaft 12, the agitator shaft 12 is connected to a stirring transmission device 2 and the stirring transmission device 2 is installed on the head 4 above the cylinder 1. The plate-frame agitator 15 improves the stirring intensity shear force and the number of up and down cycles, avoids the sedimentation of the material, and the uneven stirring, and further improves the stirring and mixing effect and the heat transfer efficiency. In addition, the finger-shaped rod 903 can also cooperate with the plate-frame agitator 15 to perform auxiliary stirring operations, so that the material can be fully mixed radially and axially in the reactor, meet the requirements of polymerization kinetics, expand the reaction material in the reactor as much as possible, form a large area of ​​film, increase the evaporation surface area, and the evaporation surface area can be continuously updated, so that the distribution range of the molecular weight is as narrow as possible to achieve a predetermined degree of polymerization.

[0037] The stirring transmission device 2 includes a frame 201 installed on the head 4, a motor 202 is installed on the frame 201, the motor 202 is connected to a reducer 203, the reducer 203 is connected to a sealing shaft 205 that movably passes through the head 4 through a coupling I 204, and a mechanical seal 206 is provided on the sealing shaft 205 for sealing the gap between the head 4 and the sealing shaft 205. The lower end of the sealing shaft 205 is connected to the stirring shaft 12 through a coupling II 207.

[0038] Both the sealing heads 4 are provided with quick opening manholes 11. During production, the quick opening manholes 11 are closed. After stopping production, the reactor can be entered through the quick opening manholes 11 to perform maintenance and cleaning operations on the equipment.

[0039] The present application effectively improves the production capacity, heat transfer capacity and stirring effect of the reactor, makes the gas-liquid phase evenly distributed, the reaction pressure is low, the material concentration is low, and the danger of explosion and agglomeration is avoided. At the same time, the catalyst is kept in a moving state and will not agglomerate; it ensures that the gas, liquid and solid phases are fully mixed and contacted in the reactor, evenly distributed and maintain a certain residence time for the continuous phase and the dispersed phase, thereby improving the production intensity and product quality, and providing an ideal device for the production of ultra-high molecular polyethylene.

[0040] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An ultra-high molecular weight polyethylene reactor, comprising a cylinder (1), wherein both upper and lower ends of the cylinder (1) are provided with a head (4), characterized in that: The inner wall of the cylinder (1) is provided with an inner jacket (6), the inner jacket (6) being connected to a water inlet pipe (7) and a water outlet pipe (8) penetrating the side wall of the cylinder (1), a finger-shaped inner cooling baffle (9) being vertically arranged in the cylinder (1), the finger-shaped inner cooling baffle (9) comprising an outer tube (901) and a finger-shaped rod (903) arranged on the outer wall of the outer tube (901), an inner tube (902) being arranged on the inner side of the outer tube (901), and the bottom of the inner tube (902) being in communication with the outer tube (901).

2. An ultra-high molecular weight polyethylene reactor according to claim 1, characterized in that: The water inlet pipe (7) and the water outlet pipe (8) are provided in multiple groups.

3. An ultra-high molecular weight polyethylene reactor according to claim 1, characterized in that: A guide plate (19) is provided in the inner jacket (6).

4. The ultra-high molecular weight polyethylene reactor according to claim 1, characterized in that: Half-pipe jackets (5) are provided on the outer walls of the two sealing heads (4).

5. The ultra-high molecular weight polyethylene reactor according to claim 1, characterized in that: The cylinder (1) is provided with an overflow discharge pipe (14) inclined downward and a catalyst feed pipe (16) inclined upward.

6. An ultra-high molecular weight polyethylene reactor according to claim 5, characterized in that: The overflow discharge pipe (14) and the catalyst feed pipe (16) are both provided with a flushing pipe (13).

7. The ultra-high molecular weight polyethylene reactor according to claim 1, characterized in that: The cylinder (1) is provided with a temperature measuring tube (17).

8. The ultra-high molecular weight polyethylene reactor according to claim 1, characterized in that: The cylinder (1) is provided with a plate-and-frame agitator (15), the plate-and-frame agitator (15) is connected to a vertically arranged agitator shaft (12), the agitator shaft (12) is connected to a agitator transmission device (2), and the agitator transmission device (2) is mounted on a head (4) above the cylinder (1).

9. The ultra-high molecular weight polyethylene reactor according to claim 8, characterized in that: The stirring transmission device (2) comprises a frame (201) mounted on a head (4), a motor (202) mounted on the frame (201), the motor (202) being connected to a reducer (203), the reducer (203) being connected to a sealing shaft (205) movably penetrating the head (4) via a coupling I (204), a mechanical seal (206) being provided on the sealing shaft (205) for sealing a gap between the head (4) and the sealing shaft (205), and the lower end of the sealing shaft (205) being connected to a stirring shaft (12) via a coupling II (207).

10. The ultra-high molecular weight polyethylene reactor according to claim 1, characterized in that: Both of the sealing heads (4) are provided with quick-opening manholes (11).

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