Para-xylene crystallization tower

Abstract

The invention provides a p-xylene crystallization tower. The p-xylene crystallization tower comprises a tower body, a cooling structure and a scraper structure, mixed xylene is contained in the tower body; the cooling structure comprises a sealing plate and liquid conveying pipes arranged at the upper end and the lower end of the sealing plate respectively, and the sealing plate surrounds the periphery of the tower body; the sealing plate is wavy; the sealing plate comprises a plurality of wave trough parts and a plurality of wave crest parts which are alternately arranged, the wave trough parts are tightly connected with the periphery of the tower body, and the sealing plate and the periphery of the tower body define a circulation channel extending in the vertical direction between any two adjacent wave trough parts; the liquid conveying pipes are arranged on the periphery of the tower body in a surrounding mode, and the two liquid conveying pipes communicate with the multiple circulation channels correspondingly. And the refrigerating medium is input into the circulation channel through the liquid conveying pipe. And the mixed xylene is cooled under the action of the refrigerating medium, and paraxylene is crystallized and separated out on the inner circumferential wall of the tower body. And the scraper structure scrapes crystals on the tower body. According to the p-xylene crystallization tower, a refrigerating medium is in close contact with the tower body, so that the dissipation of cold energy is effectively reduced, and the refrigerating effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical engineering, and particularly relates to a para-xylene crystallization tower. Background Art

[0002] Para-xylene (PX for short) is an organic chemical raw material, which can be used to produce purified terephthalic acid, dimethyl terephthalate and other substances, and is applied to multiple fields such as polyester fiber, polyester plastic, dyes and coatings.

[0003] At present, the separation methods of para-xylene include adsorption separation method and cryogenic crystallization method. Among them, the cryogenic crystallization method can be applied to the large-scale production of para-xylene, which effectively reduces the production cost of para-xylene.

[0004] The para-xylene crystallization tower, as the core equipment in the processing of the cryogenic crystallization method, mainly cools the mixed xylene through cooling structures such as air cooling and internal coil pipes, so that the para-xylene in the mixed xylene precipitates to form crystals. However, the cooling effect of this cooling structure is poor, and the size and crystallization position of the crystal particles are uneven, which is not convenient for the collection and treatment of the crystals. Summary of the Invention

[0005] The purpose of the present application is to provide a para-xylene crystallization tower with good cooling effect, which enables the crystal grains to form more uniformly.

[0006] To solve the above technical problems, the present application adopts the following technical solutions:

[0007] According to one aspect of the present application, the present application provides a para-xylene crystallization tower, which is used to crystallize and precipitate para-xylene in the mixed xylene, and includes: a tower body, a cooling structure and a scraper structure; the tower body extends in the up and down direction; a working space is opened in the tower body for accommodating the mixed xylene; the cooling structure includes a sealing plate and infusion pipes arranged at the upper and lower ends of the sealing plate respectively, and the sealing plate is wound around the outer periphery of the tower body; the sealing plate is wavy; the sealing plate includes a plurality of trough parts and a plurality of peak parts, the trough parts and the peak parts are arranged alternately, the trough parts are tightly connected to the outer periphery of the tower body, and a flow channel is formed between the sealing plate and the outer periphery of the tower body between any two adjacent trough parts, and the flow channel extends in the up and down direction; the infusion pipes are wound around the outer periphery of the tower body, and a flow port is opened on one side wall of the two infusion pipes facing the sealing plate with respect to the plurality of flow channels to communicate with the flow channels; the lower infusion pipe is used to communicate with a cold source to input a refrigerating medium into the flow channels, and the upper infusion pipe is used to output the refrigerating medium in the flow channels; the scraper structure is arranged in the working space, and the scraper structure is used to scrape off the para-xylene crystals precipitated on the inner peripheral wall of the tower body.

[0008] In some embodiments, the bottom of the trough portion extends around the outer peripheral wall of the tower body, so that the bottom of the trough portion is arc-shaped relative to the outer peripheral wall of the tower body, and the inner side surface of the trough portion is closely attached to the tower body.

[0009] In some embodiments, there are multiple such cooling structures.

[0010] In some embodiments, the scraping structure includes a rotating main shaft, a plurality of connecting components and a plurality of scrapers; the axis of the rotating main shaft is coaxial with the axis of the tower body, and the rotating main shaft is rotatably disposed through the tower body; a plurality of the connecting components are arranged around the circumference of the rotating main shaft, and the connecting components connect the rotating main shaft and the scraper; the scrapers are arranged in one-to-one correspondence with the connecting components, and the plurality of scrapers extend in the up and down direction, and the plurality of scrapers are arranged close to the inner peripheral wall of the tower body for scraping the crystals on the tower body.

[0011] In some embodiments, the distance between the outer side wall of the scraper and the inner peripheral wall of the tower body is 5 mm to 50 mm.

[0012] In some embodiments, the connecting component includes a plurality of connecting rods, the plurality of connecting rods are arranged at intervals in the up and down direction, the connecting rods extend in the radial direction of the tower body, one end of the connecting rod is connected to the rotating main shaft, and the other end of the connecting rod is connected to the scraper to drive the scraper to rotate around the axis of the rotating main shaft.

[0013] In some embodiments, the number of the connecting components and the scrapers is an even number, and the plurality of connecting components are symmetrically arranged with respect to the axis of the rotating main shaft.

[0014] In some embodiments, a rotating cylinder is provided at the top end of the tower body relative to the rotating main shaft, the rotating cylinder penetrates through the top wall of the tower body, and the rotating main shaft is rotatably received in the rotating cylinder; a plurality of working cylinders are provided at the top end of the tower body, and the plurality of working cylinders are evenly arranged around the circumference of the rotating cylinder; a reinforcing plate is provided between the working cylinder and the rotating cylinder.

[0015] In some embodiments, the rotating main shaft is divided into a plurality of main shaft sections in the up and down direction, and the plurality of main shaft sections are connected to form the rotating main shaft; the scraper is divided into a plurality of blade bodies in the up and down direction, and the plurality of blade bodies are connected to form the scraper.

[0016] In some embodiments, the para-xylene crystallization tower further includes a hoop structure; the hoop structure includes an annular mounting member and a plurality of adjusting members; the annular mounting member is sleeved outside the cooling structure; the plurality of adjusting members are arranged at intervals along the axial direction of the tower body, and the adjusting members are arranged inside the trough of the sealing plate; the adjusting members can move along the radial direction of the tower body so as to be able to press on the sealing plate.

[0017] In some embodiments, the tower body includes a cylindrical part, a top head and a bottom head. The axis of the cylindrical part extends in the up and down direction. The top head is sealingly connected to the top end of the cylindrical part, and the bottom head is sealingly connected to the inside of the cylindrical part; in the direction from top to bottom, the cross-sectional area of the bottom head gradually decreases to be conical or frustum-shaped.

[0018] From the above technical solutions, it can be seen that the present application has at least the following advantages and positive effects:

[0019] In the present application, when the para-xylene crystallization tower works, the mixed xylene is input into the working space of the tower body. The refrigerating medium is input into the flow channel through the lower infusion pipe, and after passing through the flow channel, it is output to the outside through the upper infusion pipe. The mixed xylene is cooled under the action of the refrigerating medium, so that para-xylene precipitates and crystallizes on the inner peripheral wall of the tower body. The scraper structure scrapes the crystals on the tower body. The para-xylene crystallization tower enables the refrigerating medium to be in close contact with the tower body, effectively reducing the dissipation of cold and improving the refrigeration effect, and enabling crystals to be uniformly formed on the tower body, improving the crystallization quality and production efficiency of the para-xylene crystallization tower. Description of the Drawings

[0020] Figure 1 is one of the schematic structural diagrams of the para-xylene crystallization tower of the present invention after removing the driving assembly and the scraper structure.

[0021] Figure 2 is a structural sectional view of another embodiment of the para-xylene crystallization tower of the present invention.

[0022] Figure 3 is Figure 2 the schematic structural diagram of the top head of the structure shown in

[0023] Figure 4 is the schematic structural diagram of the cooling structure connected to the cylindrical part of the present invention.

[0024] Figure 5 is Figure 4 the sectional view at A-A in

[0025] Figure 6 is Figure 5 the enlarged structural view at B in

[0026] Figure 7 It is a schematic structural diagram of the hoop structure of the present invention.

[0027] The description of the reference numerals in the drawings is as follows: 100, tower body; 110, top head; 111, rotating cylinder; 112, working cylinder; 113, reinforcing plate; 114, feed pipe; 115, overflow pipe; 120, cylindrical part; 130, bottom head; 140, working space; 200, cooling structure; 210, sealing plate; 211, trough part; 212, crest part; 213, flow passage; 220, infusion pipe; 300, scraper structure; 310, rotating main shaft; 320, connecting component; 321, connecting rod; 322, reinforcing member; 330, scraper; 400, driving component; 500, hoop structure; 510, annular mounting member; 520, adjusting member; 600, base. Detailed implementation manners

[0028] Typical implementation manners embodying the features and advantages of the present application will be described in detail in the following description. It should be understood that the present application can have various variations in different implementation manners, all of which do not depart from the scope of the present application, and the descriptions and illustrations therein are for illustrative purposes in nature and not for limiting the present application.

[0029] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation to the present application. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present application, "a plurality" means two or more unless otherwise specifically defined.

[0030] The para-xylene (PX) crystallization tower is used to process mixed xylene so that PX in the mixed xylene crystallizes out, thereby collecting PX crystals.

[0031] Figure 1 It is a schematic structural diagram of one of the structures of the para-xylene crystallization tower of the present invention after removing the driving component and the scraper structure. Figure 2 It is a structural cross-sectional view of another embodiment of the para-xylene crystallization tower of the present invention.

[0032] Refer to Figures 1 to 2 , for the convenience of understanding and description, taking the state of the PX crystallization tower during use as a reference, the up and down directions of the PX crystallization tower are used as the up and down directions in the following text.

[0033] Figure 3 is Figure 2 a schematic structural diagram of the top head of the structure shown in Figure 4 a schematic structural diagram of the cooling structure of the present invention connected to the cylindrical part. Figure 5 is Figure 4 a cross-sectional view taken along line A-A in Figure 6 is Figure 5 an enlarged structural view of part B in

[0034] Refer to Figures 1 to 6 , this application provides a PX crystallization tower (hereinafter simply referred to as the crystallization tower), which is used to crystallize and precipitate p-xylene from mixed xylene. The crystallization tower includes: a tower body 100, a cooling structure 200, and a scraper structure 300. The tower body 100 extends in the up and down directions; a working space 140 is provided inside the tower body 100 for accommodating mixed xylene. The cooling structure 200 includes a sealing plate 210 and infusion pipes 220 arranged at the upper and lower ends of the sealing plate 210 respectively. The sealing plate 210 is wound around the outer periphery of the tower body 100. The sealing plate 210 is wavy. The sealing plate 210 includes a plurality of trough portions 211 and a plurality of peak portions 212, the trough portions 211 and the peak portions 212 are arranged alternately, the trough portions 211 are tightly connected to the outer periphery of the tower body 100, and a flow channel 213 is formed between the sealing plate 210 and the outer periphery of the tower body 100 between any two adjacent trough portions 211, and the flow channel 213 extends in the up and down directions. The infusion pipes 220 are wound around the outer periphery of the tower body 100, and a flow port is provided on one side wall of the two infusion pipes 220 facing the sealing plate 210 with respect to the plurality of flow channels 213, so that the two infusion pipes 220 are respectively communicated with the plurality of flow channels 213. The lower infusion pipe 220 is used to communicate with a cold source to input a refrigerating medium into the flow channel 213, and the upper infusion pipe 220 is used to output the refrigerating medium in the flow channel 213. The scraper structure 300 is arranged in the working space 140, and the scraper structure 300 is used to scrape off the PX crystals precipitated on the inner peripheral wall of the tower body 100.

[0035] When the crystallization tower is working, the mixed xylene is input into the working space 140 through the feed pipe 114. Then, the refrigerating medium is input into the flow channel 213 through the lower infusion pipe 220. After the refrigerating medium flows upward in the flow channel 213, it is output from the upper infusion pipe 220.

[0036] When the refrigeration medium flows through the flow channel 213, the refrigeration medium contacts the peripheral side wall of the tower body 100 to perform heat exchange with the mixed xylene inside the tower body 100. The mixed xylene is cooled under the action of the refrigeration medium, so that p-xylene crystallizes and precipitates and adheres to the inner peripheral wall of the tower body 100. The scraper structure 300 scrapes the PX crystals on the tower body 100. This crystallization tower enables the refrigeration medium to be in close contact with the tower body 100, effectively reducing the dissipation of cold energy, improving the refrigeration effect, and enabling PX crystals to be uniformly formed on the tower body 100, improving the crystallization quality and production efficiency of the crystallization tower.

[0037] Refer to Figures 1 to 6 , in this embodiment, a working space 140 is provided inside the tower body 100 for accommodating the mixed xylene. The tower body 100 includes a cylindrical part 120, a top head 110 and a bottom head 130. The axis of the cylindrical part 120 extends in the up and down direction. The top head 110 is sealingly connected to the top end of the cylindrical part 120, and the bottom head 130 is sealingly connected to the inside of the cylindrical part 120, so that the top head 110, the cylindrical part 120 and the bottom head 130 can enclose to form a working space 140.

[0038] Refer to Figures 1 to 3 , in this embodiment, a rotating cylinder 111 is provided on the top head 110 opposite to the scraper structure 300. The rotating cylinder 111 extends in the up and down direction to penetrate the top head 110. A part of the scraper structure 300 is accommodated inside the rotating cylinder 111 for supporting and limiting the scraper structure 300, so as to facilitate the stable and reliable rotation of the scraper structure 300.

[0039] Refer to Figures 1 to 3 , in this embodiment, a plurality of working cylinders 112 are provided on the top head 110. The plurality of working cylinders 112 are evenly arranged around the circumferential side of the rotating cylinder 111. The working cylinder 112 penetrates the top head 110 to communicate the working space 140 and the outside. In some embodiments, the working cylinder 112 can be a manhole or a maintenance passage for manual passage.

[0040] In some embodiments, three or four working cylinders 112 can be provided on the top head 110.

[0041] Refer to Figure 3 , in this embodiment, a reinforcing plate 113 is provided between the working cylinder 112 and the rotating cylinder 111 to enhance the structural strength of the top of the tower body 100, so as to support the rotation of the scraper structure 300 and ensure the stable and reliable rotation of the scraper structure 300.

[0042] In some embodiments, the plurality of reinforcing plates 113 are symmetrically arranged with respect to the axis of the rotating cylinder 111, so as to ensure the structural strength and reliability of the rotating cylinder 111.

[0043] In some other embodiments, a cover plate is provided on the working cylinder 112 to enclose the working cylinder 112.

[0044] Referring to Figures 1 to 3 , in the present embodiment, a feed pipe 114 is provided on the top head 110. The feed pipe 114 penetrates through the top head 110 to input the external mixed xylene into the working space 140.

[0045] In some embodiments, a feed valve is provided on the feed pipe 114 to be able to control the input of the mixed xylene.

[0046] In some embodiments, an overflow pipe 115 is further provided on the top head 110. The overflow pipe 115 is used to discharge the mixed xylene in the working space 140 that exceeds the preset liquid level, thereby ensuring the safety and reliability of the crystallization tower.

[0047] In some other embodiments, the overflow pipe 115 may not be provided on the top head 110, and an overflow port may be provided on the top head 110 to be able to remove the mixed xylene in the working space 140 that exceeds the preset liquid level. In some other embodiments, the feed pipe 114 may not be provided on the top head 110, and a feed port may be provided on the top head 110. In some other embodiments, the connecting pipe may not be provided on the top head 110, and a manhole may be provided on the top head 110.

[0048] Referring to Figures 1 to 2 , in the present embodiment, a crystallization discharge port and a mother liquor discharge port are provided on the bottom head 130. The crystallization discharge port is used to output PX crystals to the outside. The mother liquor discharge port is used to output the mother liquor at the bottom of the working space 140 to the outside, thereby facilitating the cyclic operation of the crystallization tower and improving the working efficiency of the crystallization tower.

[0049] In some embodiments, in the up-down direction, the cross-sectional area of the bottom head 130 gradually decreases to be in a conical or frustum shape. The PX crystals converge at the bottom of the bottom head 130 during the scraping process, thereby facilitating the collection and discharge of the PX crystals.

[0050] Referring to Figure 2 , in the present embodiment, the crystallization tower includes a scraper structure 300. The scraper structure 300 includes a rotating main shaft 310, a plurality of connecting components 320, and a plurality of scrapers 330. The axis of the rotating main shaft 310 is coaxial with the axis of the tower body 100, and the rotating main shaft 310 is rotatably disposed within the tower body 100. The plurality of connecting components 320 are wound around the circumferential side of the rotating main shaft 310, and the connecting components 320 connect the rotating main shaft 310 and the scraper 330. The scrapers 330 are provided in one-to-one correspondence with the connecting components 320. The plurality of scrapers 330 extend in the up-down direction, and the plurality of scrapers 330 are disposed close to the inner peripheral wall of the tower body 100 to be used for scraping the crystals on the tower body 100.

[0051] When PX crystals precipitate on the inner peripheral wall of the cylindrical portion 120, the rotating main shaft 310 rotates, so as to drive the scraper 330 to rotate through the connecting assembly 320. During the rotation, the scraper 330 can abut against and squeeze the PX crystals, so that the PX crystals are separated and dropped from the cylindrical portion 120, thereby realizing the collection of PX crystals.

[0052] Moreover, when the scraper structure 300 rotates around the axis of the rotating main shaft 310, the connecting assembly 320 and the scraper 330 can also stir the mixed xylene in the working space 140, so that the concentration distribution of each component in the mixed xylene is more uniform, avoiding too high or too low local concentration, improving the uniformity of PX crystals, reducing the size difference of PX crystals, avoiding poor crystallization caused by local overcooling or overheating, and moreover, it can also increase the fluidity of the mixed xylene, promote the diffusion and collision of PX molecules, and accelerate the crystallization efficiency of PX.

[0053] Refer to Figure 2 , in this embodiment, the rotating main shaft 310 extends in the up and down direction. The upper end of the rotating main shaft 310 is rotatably received in the rotating cylinder 111 of the top head 110 to limit the rotating main shaft 310 and ensure the stability and reliability of the rotating main shaft 310. The lower end of the rotating main shaft 310 is rotatably passed through the bottom head 130 to ensure the rotational stability and reliability of the rotating main shaft 310.

[0054] In some embodiments, the rotating main shaft 310 is divided into multiple main shaft sections in the up and down direction. The multiple main shaft sections are connected to form the rotating main shaft 310, thereby facilitating the production, assembly, disassembly and maintenance of the rotating main shaft 310, improving the assembly efficiency of the crystallization tower, and reducing the production, transportation and assembly costs of the crystallization tower.

[0055] In some other embodiments, the multiple main shaft sections can be detachably connected by means such as bolt connection, snap connection, mortise and tenon connection, etc. The multiple main shaft sections can also be fixedly connected by means such as welding connection, etc.

[0056] Refer to Figure 2 , in this embodiment, the connecting assembly 320 is used to connect the rotating main shaft 310 and the scraper 330 to ensure the structural strength and stability of the scraper 330.

[0057] The connecting assembly 320 includes a plurality of connecting rods 321. The plurality of connecting rods 321 are arranged at intervals in the up and down direction. The connecting rods 321 extend in the radial direction of the tower body 100. One end of the connecting rod 321 is connected to the rotating main shaft 310, and the other end of the connecting rod 321 is connected to the scraper 330 to drive the scraper 330 to rotate around the axis of the rotating main shaft 310. The plurality of connecting rods 321 can ensure the connection strength and stability between the scraper 330 and the rotating main shaft 310, so that the scraper 330 can stably scrape off the PX crystals.

[0058] In some embodiments, the connecting rod 321 can be connected to the rotating main shaft 310 and the scraper 330 by means of flange connection, bolt connection, etc., so as to facilitate the disassembly and assembly of the scraper structure 300.

[0059] In some embodiments, the connecting component 320 may further include a plurality of reinforcing members 322. The plurality of reinforcing members 322 are connected to the opposite ends of the upper and lower adjacent connecting rods 321, thereby enhancing the structural strength and reliability of the connecting component 320, reducing the swing amplitude during the rotation of the scraper 330, and ensuring the stability and reliability of the scraper structure 300 during rotation.

[0060] In other embodiments, the reinforcing member 322 may be a structure such as a connecting rope, a connecting rod 321, or a connecting plate.

[0061] Refer to Figure 2 , in this embodiment, the scraper 330 extends in the up and down direction, and the scraper 330 is connected to the connecting component 320 so as to be able to rotate around the axis of the rotating main shaft 310.

[0062] In some embodiments, the scraper 330 is divided into a plurality of blade bodies in the up and down direction, and the plurality of blade bodies are connected to form the scraper 330, thereby facilitating the production, transportation, and assembly of the scraper 330, and thus reducing the production and assembly costs of the scraper 330.

[0063] In other embodiments, the plurality of blade bodies can be detachably connected by means of bolt connection, snap connection, mortise and tenon connection, etc. The plurality of blade bodies can also be fixedly connected by means of welding connection, etc.

[0064] In some embodiments, the distance between the outer side wall of the scraper 330 and the inner peripheral wall of the tower body 100 is 5 mm to 50 mm, so as to be able to scrape off the fixed-shaped PX crystals, thereby ensuring the uniformity of the PX crystals and improving the quality of the PX crystals.

[0065] Refer to Figure 2 , in this embodiment, the number of the connecting components 320 and the scrapers 330 is an even number. The plurality of connecting components 320 are symmetrically arranged with respect to the axis of the rotating main shaft 310, so as to ensure the stability and reliability of the scraper structure 300 during rotation and the stability of the crystallization tower.

[0066] Refer to Figure 2 , in this embodiment, the crystallization tower further includes a driving component 400. The driving component 400 can be arranged on the upper side of the top head 110, and the driving component 400 is in transmission connection with the rotating main shaft 310, so that the driving component 400 can drive the rotating main shaft 310 to rotate, and thus drive the scraper 330 to rotate through the connecting component 320 to scrape off the PX crystals on the cylindrical part 120.

[0067] In some embodiments, the driving assembly 400 may include a motor and a speed reducer. The speed reducer is drivingly connected to the motor and the rotating main shaft 310 to be able to adjust the rotation speed of the rotating main shaft 310, so as to realize the stirring speed of the mixed xylene and the scraping speed of the PX crystals.

[0068] Refer to Figure 1 、 Figure 2 、 Figures 4 to 6 , in this embodiment, the crystallization tower further includes a cooling structure 200. The cooling structure 200 is arranged outside the tower body 100 to be able to exchange cold energy with the tower body 100, so as to cool the mixed xylene, enabling the crystallization of p-xylene.

[0069] The cooling structure 200 includes a sealing plate 210 and infusion pipes 220 arranged at the upper and lower ends of the sealing plate 210 respectively. The sealing plate 210 is wound around the outer periphery of the tower body 100. The sealing plate 210 is wavy. The sealing plate 210 includes a plurality of trough portions 211 and a plurality of peak portions 212, which are arranged alternately. The trough portions 211 are tightly connected to the outer periphery of the tower body 100. The sealing plate 210 and the outer periphery of the tower body 100 enclose a flow channel 213 between any two adjacent trough portions 211, and the flow channel 213 extends in the up and down direction. The refrigeration medium can flow in the flow channel 213, and there is no barrier between the refrigeration medium and the tower body, so that the refrigeration medium can directly contact the tower body 100, facilitating the transfer of the cold energy in the refrigeration medium to the tower body and exchanging cold energy with the mixed xylene, thereby effectively improving the crystallization efficiency of the PX crystals, improving the uniformity of the formation of the PX crystals, and ensuring the precipitation quality of the PX crystals.

[0070] In some embodiments, the bottom of the trough portion 211 extends around the outer peripheral wall of the tower body 100, so that the inner side surface of the trough portion 211 is arc-shaped relative to the outer peripheral wall of the tower body 100, and the inside of the trough portion 211 is tightly attached to the tower body 100.

[0071] In some embodiments, the head and tail of the sealing plate 210 are connected in the circumferential direction, so that the sealing plate 210 is looped around the outer periphery of the cylindrical portion 120, thereby ensuring the cold energy exchange efficiency between the cooling structure 200 and the tower body 100.

[0072] Refer to Figure 1 、 Figure 2 、 Figures 4 to 6 , in this embodiment, the infusion pipes 220 are wound around the outer periphery of the tower body 100. On one side wall of the two infusion pipes 220 facing the sealing plate 210, flow openings are provided for each of the plurality of flow channels 213 to communicate with the flow channels 213. The lower infusion pipe 220 is used to communicate with a cold source to input the refrigeration medium into the flow channel 213. The upper infusion pipe 220 is used to output the refrigeration medium in the flow channel 213.

[0073] When the crystallization tower is working, the refrigeration medium in the cold source is input into the lower infusion pipe 220, and then input into the circulation channel 213 through the lower infusion pipe 220.

[0074] When the refrigeration medium flows upward in the circulation channel 213, the refrigeration medium is in full contact with the peripheral side wall of the tower body 100, so as to exchange heat with the mixed xylene in the tower body 100, so that p-xylene in the mixed xylene crystallizes out on the inner peripheral wall of the tower body 100.

[0075] When the refrigeration medium flows out of the circulation channel 213, it enters the upper infusion pipe 220 and is finally output outside the crystallization tower through the upper infusion pipe 220.

[0076] In some embodiments, the upper infusion pipe 220 can also be connected to the cold source, so as to facilitate the recycling of the refrigeration medium.

[0077] In some embodiments, the cold source can be independent of the crystallization tower or can be part of the crystallization tower.

[0078] Refer to Figure 1 、 Figure 2 and Figure 4 , in this embodiment, there can be multiple cooling structures 200, and the multiple cooling structures 200 are arranged in sequence in the up and down direction, so as to fully cool the cylindrical part 120 through the multiple cooling structures 200 and improve the production efficiency of PX crystals.

[0079] In some embodiments, when the length of the tower body 100 in the up and down direction is relatively low, the cooling structure 200 can be one, so that the cooling structure 200 can fully cool the cylindrical part 120, so as to ensure the precipitation efficiency and quality of PX crystals.

[0080] Figure 7 is a schematic structural diagram of the hoop structure of the present invention.

[0081] Refer to Figure 1 、 Figure 2 and Figure 7 , in this embodiment, the p-xylene crystallization tower further includes a hoop structure 500. The hoop structure 500 includes an annular mounting member 510 and a plurality of adjusting members 520. The annular mounting member 510 is sleeved outside the cooling structure 200. The plurality of adjusting members 520 are arranged at intervals around the axis of the tower body 100, and the adjusting members 520 are arranged inside the trough of the sealing plate 210. The adjusting members 520 can move radially along the tower body 100 so as to be able to press on the sealing plate 210.

[0082] During the operation of the crystallization tower, the roundness of the cylindrical part 120 will affect the uniformity and particle size of the PX crystal formation on the cylindrical part 120. During the production, transportation, and assembly of the crystallization tower, when the roundness of the cylindrical part 120 changes, the operator can adjust the adjusting member 520 to make the adjusting member 520 press against the sealing plate 210, thereby adjusting the roundness of the cylindrical part 120. The hoop structure 500 can improve the forming efficiency and quality of the PX crystal by adjusting the roundness of the cylindrical part 120, making the PX crystals scraped off by the scraper structure 300 have a consistent shape. Moreover, it can also prevent the scraper structure 300 from coming into contact and friction with the cylindrical part 120, avoid damage to the crystallization tower, and ensure the production efficiency and safety of the crystallization tower.

[0083] In some embodiments, the annular mounting member 510 can be a frame structure to reduce the weight of the annular mounting member 510 and facilitate the installation of the hoop structure 500. In other embodiments, the annular mounting member 510 can also be an annular structure formed by combining multiple plates, so that the annular mounting member 510 can be stably connected to the sealing plate 210 and it is only necessary to facilitate the movement of the adjusting member 520 relative to the annular mounting member 510.

[0084] In other embodiments, the annular mounting member 510 can be composed of multiple sub-sections spliced in sequence, thus facilitating the installation of the annular mounting member 510.

[0085] In some embodiments, screw holes are provided on the annular mounting member 510, and the adjusting member 520 is threadedly connected to the annular mounting member 510. When the adjusting member 520 rotates relative to the annular mounting member 510, the adjusting member 520 moves along the radial direction of the cylindrical part 120, thereby adjusting the pressure of the adjusting member 520 against the sealing plate 210. The adjusting member 520 squeezes the inside of the trough portion 211 of the sealing plate 210 to squeeze the cylindrical part 120, thereby realizing fine adjustment of the roundness of the cylindrical part 120.

[0086] In other embodiments, the end face of the adjusting member 520 facing the sealing plate 210 is an arc surface, so as to reduce the excessive local pressure at the contact between the adjusting member 520 and the sealing plate 210 and damage the sealing plate 210 and the cylindrical part 120.

[0087] In other embodiments, the end face of the adjusting member 520 facing the sealing plate 210 can also be a flat surface.

[0088] In some embodiments, there are multiple hoop structures 500, and the multiple hoop structures 500 are arranged at intervals in the up-down direction to facilitate the operator to adjust multiple positions of the vertically extending cylindrical part 120, thereby ensuring the structural strength, reliability, and safety of the tower body 100.

[0089] In this embodiment, the crystallization tower further includes a base 600. The base 600 is fixedly connected to the bottom head 130 and / or the cylindrical part 120 to support the crystallization tower.

[0090] Referring to Figures 1 to 7 , this application provides a p-xylene crystallization tower. When the p-xylene crystallization tower is working, first, the mixed xylene is input into the working space 140 of the tower body 100 through the feed pipe 114, and then the refrigeration medium is input into the plurality of flow channels 213 from the cold source through the lower infusion pipe 220, and finally output to the outside through the upper infusion pipe 220.

[0091] When the refrigeration medium flows in the flow channels 213, it comes into full contact with the cylindrical part 120 for cold quantity interaction. After the cold quantity in the refrigeration medium is input into the mixed xylene through the cylindrical part 120, the mixed xylene absorbs the cold quantity and cools down, and p-xylene crystallizes out on the inner peripheral wall of the cylindrical part 120. This p-xylene crystallization tower enables the refrigeration medium to be in close contact with the tower body 100, effectively reducing the dissipation of cold quantity, improving the refrigeration effect, and enabling PX crystals to be uniformly formed on the tower body 100, improving the crystallization quality and production efficiency of the p-xylene crystallization tower.

[0092] When p-xylene crystallizes out, the motor drives the rotating main shaft 310 to rotate, and the rotating main shaft 310 drives the scraper 330 to rotate through the connecting component 320. During the rotation of the scraper structure 300, on the one hand, it scrapes off the PX crystals on the inner peripheral wall of the cylindrical part 120, so as to ensure that the sizes of the fallen PX crystals are within the same specification range; on the other hand, it stirs the mixed xylene, so as to make the components in the mixed xylene uniform and ensure the quality of the PX crystals when p-xylene crystallizes out.

[0093] After the PX crystals are scraped off, they will fall to the bottom head 130 and then be output to the outside through the crystallization discharge port. The mixed xylene in the working space 140 passes through the mother liquor discharge port at the bottom.

[0094] The above embodiments are only illustrative examples of the structures. The structures in each embodiment are not fixedly combined structures. Without structural conflicts, the structures in multiple embodiments can be arbitrarily combined and used.

[0095] Although this application has been described with reference to several typical embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since this application can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be broadly construed within the spirit and scope defined by the appended claims. Therefore, all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A p-xylene crystallization tower, which is used to crystallize p-xylene in mixed xylene, characterized in that: include: A tower body extending in the up-down direction; a working space is provided in the tower body for accommodating the mixed xylene; A cooling structure, comprising a sealing plate and a liquid infusion tube arranged at the upper and lower ends of the sealing plate, wherein the sealing plate is arranged around the outer periphery of the tower body; the sealing plate is wavy; the sealing plate comprises a plurality of troughs and a plurality of crests, the troughs and crests are arranged alternately, the troughs are tightly connected to the outer periphery of the tower body, the sealing plate and the outer periphery of the tower body are enclosed between any two adjacent troughs to form a circulation channel, and the circulation channel extends in the up-down direction; the liquid infusion tube is arranged around the outer periphery of the tower body, and a side wall of the two liquid infusion tubes facing the sealing plate is provided with a circulation port relative to the plurality of circulation channels to connect the circulation channels; the liquid infusion tube at the lower end is used to communicate with a cold source to input a refrigerant into the circulation channel, and the liquid infusion tube at the upper end is used to output the refrigerant in the circulation channel; A scraper structure is arranged in the working space and is used to scrape off the p-xylene crystals precipitated on the inner peripheral wall of the tower body.

2. The paraxylene crystallization tower according to claim 1, characterized in that The bottom of the trough portion extends around the outer peripheral wall of the tower body, so that the inner side surface of the trough portion is arc-shaped relative to the outer peripheral wall of the tower body, and the inside of the trough portion is closely fitted to the tower body.

3. The paraxylene crystallization tower according to claim 1, characterized in that The number of the cooling structures is multiple.

4. The paraxylene crystallization tower according to claim 1, characterized in that The scraper structure includes a rotating main shaft, multiple connecting components and multiple scrapers; the axis of the rotating main shaft is coaxial with the axis of the tower body, and the rotating main shaft is rotatably inserted into the tower body; multiple connecting components are arranged around the circumference of the rotating main shaft, and the connecting components connect the rotating main shaft and the scrapers; the scrapers are arranged in a one-to-one correspondence with the connecting components, and multiple scrapers extend in the up and down directions, and multiple scrapers are arranged close to the inner wall of the tower body to scrape off crystals on the tower body.

5. The paraxylene crystallization tower according to claim 4, characterized in that The distance between the outer wall of the scraper and the inner wall of the tower body is 5 mm to 50 mm.

6. The paraxylene crystallization tower according to claim 4, characterized in that: The connecting assembly includes a plurality of connecting rods, which are arranged at intervals in the up-down direction, and extend radially along the tower body. One end of the connecting rod is connected to the rotating main shaft, and the other end of the connecting rod is connected to the scraper to drive the scraper to rotate around the axis of the rotating main shaft.

7. The paraxylene crystallization tower according to claim 4, characterized in that: The number of the connecting components and the scrapers is an even number, and the plurality of connecting components are symmetrically arranged relative to the axis of the rotating main shaft.

8. The paraxylene crystallization tower according to claim 4, characterized in that: A rotating cylinder is disposed at the top of the tower body relative to the rotating main shaft, the rotating cylinder is penetrated through the top wall of the tower body, and the rotating main shaft is rotatably accommodated in the rotating cylinder; A plurality of working cylinders are arranged at the top of the tower body, and the plurality of working cylinders are evenly arranged around the circumference of the rotating cylinder; a reinforcing plate is arranged between the working cylinders and the rotating cylinder.

9. The paraxylene crystallization tower according to claim 5, characterized in that: The rotating main shaft is divided into a plurality of main shaft sections along the upper and lower sides, and a plurality of the main shaft sections are connected to form the rotating main shaft; The scraper is divided into a plurality of blade bodies along the up-down direction, and the plurality of blade bodies are connected to form the scraper.

10. The paraxylene crystallization tower according to claim 1, characterized in that: The paraxylene crystallization tower also includes a hoop structure; The clamp structure includes an annular mounting member and a plurality of adjusting members; the annular mounting member is sleeved outside the cooling structure; the plurality of adjusting members are arranged at intervals around the axial direction of the tower body, and the adjusting members are arranged inside the trough of the sealing plate; the adjusting members can move radially along the tower body so as to be pressed on the sealing plate.

11. The paraxylene crystallization tower according to claim 1, characterized in that: The tower body comprises a cylindrical portion, a top head and a bottom head, the axis of the cylindrical portion extends in the up-down direction, the top head is sealed and connected to the top end of the cylindrical portion, and the bottom head is sealed and connected to the inner side surface of the cylindrical portion; In a direction from top to bottom, the cross-sectional area of ​​the bottom head gradually decreases to be in a cone or frustum shape.

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