Crystallization device for p-xylene

Abstract

The utility model discloses a p-xylene crystallization device which at least comprises a raw material input pipeline, the at least one crystallization unit is connected with the raw material input pipeline; the at least one separation unit is connected with the outlet of the crystallization unit; the mother liquor buffer tank is connected with an outlet of the separation unit; an inlet of the mother liquor pump is connected with an outlet of the mother liquor buffer tank; the subcooler is connected with an outlet of the mother liquor pump; the industrial wind input pipeline is connected with the other inlet of the mother liquor pump; and the industrial wind output pipeline is connected with the other outlet of the mother liquor pump. According to the p-xylene crystallization device provided by the utility model, the operation stability of the crystallization device can be improved.

Description

Technical Field

[0001] This utility model relates to the field of chemical separation technology, specifically to a crystallization apparatus for paraxylene. Background Technology

[0002] p-Xylene is a crucial basic chemical in the petrochemical industry, primarily used in the production of polyterephthalic acid (PET), which in turn manufactures polyester fibers, plastic bottles, and films. During the preparation of p-xylene, isomers of C8 aromatics such as ethylbenzene, o-xylene, and m-xylene are often present. Therefore, the C8 aromatic mixture must undergo crystallization to produce high-purity p-xylene. Due to the freezing point differences between the isomers, the temperature of the C8 aromatic mixture needs to be lowered to approximately -70°C for p-xylene to precipitate. However, the temperature of the C8 aromatic mixture is transmitted to the pump transporting the mixture, causing pump malfunction and hindering the smooth progress of the crystallization process. Utility Model Content

[0003] The purpose of this invention is to provide a crystallization apparatus for paraxylene, which can ensure the normal operation of the pump in the crystallization apparatus and improve the stability of the crystallization apparatus operation.

[0004] To achieve the above-mentioned and other related objectives, this utility model is implemented through the following technical solution.

[0005] This invention provides a crystallization apparatus for p-xylene, comprising at least:

[0006] Raw material input pipeline;

[0007] At least one crystallization unit is connected to the raw material input pipeline;

[0008] At least one separation unit is connected to the outlet of the crystallization unit;

[0009] A mother liquor buffer tank is connected to one outlet of the separation unit;

[0010] A mother liquor pump, one inlet of which is connected to the outlet of the mother liquor buffer tank;

[0011] The subcooler is connected to one outlet of the mother liquor pump;

[0012] An industrial air inlet duct is connected to another inlet of the mother liquor pump; and

[0013] An industrial air output pipe is connected to another outlet of the mother liquor pump.

[0014] In one embodiment of the present invention, the mother liquor pump includes a pump body, the outlet of the mother liquor buffer tank is connected to the inlet of the pump body, and the inlet of the subcooler is connected to the outlet of the pump body.

[0015] In one embodiment of the present invention, the mother liquor pump further includes a bearing housing and a jacket, the bearing housing and the jacket being disposed on the same side of the pump body, and the jacket surrounding the bearing housing.

[0016] In one embodiment of this utility model, the outlet of the industrial air input pipe is connected to the inlet of the jacket, and the inlet of the industrial air output pipe is connected to the outlet of the jacket.

[0017] In one embodiment of the present invention, the crystallization device further includes a medium transmission pipeline, and a portion of the industrial air input pipeline is arranged around the medium transmission pipeline.

[0018] In one embodiment of the present invention, the separation unit includes a first separator, the inlet of which is connected to the outlet of the crystallization unit, and one outlet of the first separator is connected to the inlet of the mother liquor buffer tank.

[0019] In one embodiment of the present invention, the separation unit further includes a re-slurry tank, the inlet of which is connected to another outlet of the first separator.

[0020] In one embodiment of the present invention, the separation unit further includes a second separator, the inlet of which is connected to the outlet of the heavy slurry tank.

[0021] In one embodiment of the present invention, the crystallization apparatus further includes a recovery liquid buffer tank, the inlet of which is connected to the outlet of the second separator.

[0022] In one embodiment of the present invention, the crystallization apparatus further includes an isomerization reaction system, the inlet of which is connected to the outlet of the recovery liquid buffer tank.

[0023] In summary, this invention provides a crystallization apparatus for para-xylene. By improving the crystallization apparatus, it avoids the low temperature of the mother liquor during crystallization, which could lead to excessively low temperatures in the bearing housing of the mother liquor pump. This ensures the normal operation of the mother liquor pump during the crystallization process and extends its service life. Furthermore, the para-xylene crystallization apparatus provided by this invention guarantees the smooth progress of the crystallization process and improves the operational stability of the crystallization apparatus.

[0024] Of course, implementing any of the methods of this utility model does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of a p-xylene crystallization apparatus according to one embodiment of the present invention.

[0027] Figure 2 for Figure 1 A schematic diagram of the mother liquor pump.

[0028] Marker explanation:

[0029] 10. Raw material input pipeline; 11. Crystallization unit; 111. Primary crystallizer; 112. Secondary crystallizer; 113. Tertiary crystallizer; 114. Transfer pump; 12. Separation unit; 121. First separator; 122. Re-slurry tank; 123. Second separator; 13. Mother liquor buffer tank; 14. Mother liquor pump; 141. Pump body; 142. Bearing housing; 143. Rotating parts; 144. Pump shaft; 145. Jacket; 146. Oil cup; 15. Subcooler; 16. Recovery liquid buffer tank; 17. Booster pump; 18. Industrial air input pipeline; 181. Control valve; 19. Industrial air output pipeline; 20. Media transfer pipeline; 201. Switch valve; 21. Isomerization reaction system. Detailed Implementation

[0030] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this utility model can be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0031] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0032] In this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used only for descriptive and distinguishing purposes and should not be construed as indicating or implying relative importance.

[0033] Please see Figures 1 to 2 As shown, this utility model provides a crystallization apparatus for paraxylene, including, for example, a raw material input pipe 10, a crystallization unit 11, a separation unit 12, a mother liquor buffer tank 13, a mother liquor pump 14, a supercooler 15, an industrial air input pipe 18, and an industrial air output pipe 19. The crystallization unit 11 is connected to the raw material input pipe 10, the separation unit 12 is connected to the outlet of the crystallization unit 11, the mother liquor buffer tank 13 is connected to one outlet of the separation unit 12, the mother liquor pump 14 has multiple inlets and multiple outlets, one inlet of the mother liquor pump 14 is connected to the outlet of the mother liquor buffer tank 13, another inlet is connected to the industrial air input pipe 18, one outlet of the mother liquor pump 14 is connected to the supercooler 15, and another outlet is connected to the industrial air output pipe 19. The low temperature of the solution entering the mother liquor pump 14 from the mother liquor buffer tank 13 can affect the normal operation of the mother liquor pump 14. Therefore, in the p-xylene crystallization device provided by this utility model, the mother liquor pump 14 is heated by setting an industrial air input pipe 18 to avoid the low temperature affecting the operation of the mother liquor pump 14, so as to ensure the smooth operation of the mother liquor pump 14 and the entire crystallization device.

[0034] Please see Figure 1 As shown, in one embodiment of this utility model, the raw material input pipe 10 provides raw materials to the crystallization device. The raw materials are, for example, a mixture with 8 carbon molecules (C8). The C8 mixture includes, for example, p-xylene and impurities, including at least one isomer of o-xylene, m-xylene, and ethylbenzene. Since p-xylene and its isomers have large differences in freezing points, p-xylene can be precipitated from the C8 mixture by crystallization to obtain a high-purity p-xylene product.

[0035] Please see Figure 1As shown, in one embodiment of this utility model, the crystallization unit 11 is connected to the raw material input pipe 10. The crystallization unit 11 may be at least one; when there are multiple crystallization units 11, they are connected in parallel and then connected to the raw material input pipe 10. In this embodiment, there are two crystallization units 11 connected in parallel, and each crystallization unit 11 includes multiple crystallization tanks connected in series. Specifically, in this embodiment, taking three crystallization tanks connected in series in each crystallization unit 11 as an example, the crystallization unit 11 will be described. Each crystallization unit 11 includes, for example, a primary crystallization tank 111, a secondary crystallization tank 112, and a tertiary crystallization tank 113. The inlet of the primary crystallization tank 111 is connected to the outlet of the raw material input pipe 10, the outlet of the primary crystallization tank 111 is connected to the inlet of the secondary crystallization tank 112, and the outlet of the secondary crystallization tank 112 is connected to the inlet of the tertiary crystallization tank 113.

[0036] Please see Figure 1 As shown, in one embodiment of this utility model, the C8 mixture in the raw material input pipe 10 enters the crystallization unit 11 as mother liquor and first enters the primary crystallization tank 111. The primary crystallization tank 111 cools the mother liquor to a first temperature. After the para-xylene in the mother liquor precipitates and adheres to the inner wall of the primary crystallization tank 111, it flows out from the bottom of the primary crystallization tank 111. However, some para-xylene will inevitably remain in the mother liquor flowing out from the bottom. Therefore, the mother liquor flowing out from the bottom of the primary crystallization tank 111 is guided to the secondary crystallization tank 112 to further recover para-xylene and improve the yield of para-xylene. Specifically, the mother liquor flowing from the bottom of the primary crystallizer 111 flows into the secondary crystallizer 112. The secondary crystallizer 112 cools the mother liquor to a second temperature, causing the para-xylene in the mother liquor to precipitate and adhere to the inner wall of the secondary crystallizer 112. The mother liquor then flows out from the bottom of the secondary crystallizer 112. Similarly, the mother liquor flowing from the bottom of the secondary crystallizer 112 is directed into the tertiary crystallizer 113. The tertiary crystallizer 113 cools the mother liquor to a third temperature, causing the para-xylene in the mother liquor to precipitate and adhere to the inner wall of the tertiary crystallizer 113. The mother liquor then flows out from the bottom of the tertiary crystallizer 113. The first temperature is, for example, higher than the second temperature, and the second temperature is, for example, higher than the third temperature. Specifically, the first temperature is, for example, -45℃ to -49℃, the second temperature is, for example, -55℃ to -60℃, and the third temperature is, for example, -65℃ to -70℃.

[0037] Please see Figure 1As shown, in one embodiment of this utility model, each crystallization unit 11 further includes a transfer pump 114. Specifically, in each crystallization unit 11, the transfer pump 114 is installed on the outlet pipe of each crystallizer to increase the pressure of the mother liquor flowing out from the bottom of the crystallizer, so that the mother liquor flowing out from the bottom of the previous crystallizer can smoothly flow into the next crystallizer or the next process, such as the separation unit 12. In this embodiment, a transfer pump 114 is connected between the bottom of the primary crystallizer 111 and the top of the secondary crystallizer 112, between the bottom of the secondary crystallizer 112 and the top of the tertiary crystallizer 113, and at the bottom of the tertiary crystallizer 113.

[0038] Please see Figure 1 As shown, in one embodiment of this utility model, the separation unit 12 is connected to the outlet of the crystallization unit 11. Specifically, in this embodiment, the outlets of the two crystallization units 11 are connected in parallel and then connected to the separation unit 12. Furthermore, in the two crystallization units 11, the outlets of the transfer pumps 114 connected to the bottom of the two three-stage crystallization tanks 113 are connected in parallel and then connected to the separation unit 12. Since the mother liquor from the bottom of the three-stage crystallization tank 113 inevitably carries paraxylene crystals from the inner wall of the three-stage crystallization tank 113 into the transfer pumps 114, the separation unit 12 is used to separate the crystals from the mother liquor, thereby improving the recovery rate of paraxylene. The separation unit 12 can be at least one, or multiple, connected in parallel and then connected to the crystallization unit 11. In this embodiment, there are two separation units 12, each including, for example, a first separator 121, a re-slurry tank 122, and a second separator 123.

[0039] Please see Figure 1 As shown, in one embodiment of this invention, the first separator 121 is connected to the outlet of a transfer pump 114 located at the bottom of the three-stage crystallizer 113. The first separator 121 is, for example, a centrifuge or filter, a solid-liquid separator. Specifically, the mother liquor and the carried paraxylene crystals flow from the bottom of the three-stage crystallizer 113 into the transfer pump 114, and then into the first separator 121, where solid-liquid separation is performed. The first separator 121 has multiple outlets; after separating the paraxylene crystals carried in the mother liquor, the mother liquor exits from one outlet, while the mother liquor exits from another outlet.

[0040] Please see Figure 1As shown, in one embodiment of this invention, the re-slurry tank 122 is connected to one outlet of the first separator 121. Specifically, in the first separator 121, the p-xylene crystals carried in the mother liquor are separated and enter the re-slurry tank 122. Simultaneously, solvent enters from the top of the re-slurry tank 122 and mixes with the p-xylene crystals, outputting a slurry of the solvent and p-xylene crystals. The solvent may include, for example, toluene or heptane, or a C8 filtrate. During the mixing process of the solvent and p-xylene crystals, the solvent washes the p-xylene crystals, dissolving impurities such as m-xylene, o-xylene, and ethylbenzene remaining on the surface of the p-xylene crystals, thereby improving the purity of the p-xylene crystals.

[0041] Please see Figure 1 As shown, in one embodiment of this invention, the second separator 123 is connected to the outlet of the re-slurry tank 122. The second separator 123 is, for example, a solid-liquid separator such as a centrifuge or a filter. Specifically, the mixed slurry output from the re-slurry tank 122 enters the second separator 123, where the second separator 123 separates the solids and liquids in the mixed slurry. The p-xylene crystals are drawn out of the second separator 123 in solid form for later use, while the solvent, along with impurities such as m-xylene, o-xylene, and ethylbenzene dissolved in the solvent, flow out of the second separator 123 in liquid form. The solid content in the mixed slurry is, for example, 10wt% to 20wt%, and the liquid content is, for example, 80wt% to 90wt%.

[0042] Please see Figure 1 As shown, in one embodiment of this utility model, the outlet of the second separator 123 is connected to a recovery liquid buffer tank 16. In this embodiment, the outlets of the second separators 123 in the two separation units 12 are connected in parallel and then connected to the recovery liquid buffer tank 16. Specifically, the second separator 123 separates the liquid, solvent, and impurities such as m-xylene, o-xylene, and ethylbenzene dissolved in the solvent from the mixed slurry, and these are stored together in liquid form in the recovery liquid buffer tank 16. The temperature of the liquid inside the second separator 123 is, for example, -50°C to -60°C.

[0043] Please see Figure 1 As shown, in one embodiment of this utility model, the outlet of the recovery liquid buffer tank 16 is connected to a booster pump 17 to increase the pressure of the solvent and impurities, so that the solvent and impurities in the recovery liquid buffer tank 16 can flow smoothly through the subsequent isomerization reaction system 21.

[0044] Please see Figure 1As shown, in one embodiment of this invention, the outlet of the booster pump 17 is connected to an isomerization reaction system 21 to deliver solvent and impurities into the isomerization reaction system 21. The isomerization reaction system 21 is, for example, a vacuum distillation column. In the re-slurry tank 122, when the solvent dissolves impurities on the surface of the para-xylene crystals, some para-xylene crystals will inevitably be dissolved. Therefore, the mixed slurry output from the re-slurry tank 122 includes not only undissolved para-xylene crystals, solvent, and impurities such as m-xylene, o-xylene, and ethylbenzene dissolved in the solvent, but also para-xylene dissolved in the solvent. The dissolved para-xylene, impurities, and solvent are separated from the second separator 123 in liquid form and enter the recovery buffer tank 16. After passing through the booster pump 17, they enter the isomerization reaction system 21. Based on the boiling point difference, the isomerization reaction system 21 separates the impurities and para-xylene in the liquid. The solvent flows out from the top of the isomerization reaction system 21 for recycling, while the impurities and para-xylene return from the bottom of the isomerization reaction system 21 to the primary crystallizer 111 in the crystallization unit 11. The primary crystallizer 111 further recovers the para-xylene from the bottom of the crystallizer by crystallization to improve the recovery rate of para-xylene. In the liquid flowing into the isomerization reaction system 21, the content of p-xylene is, for example, 20 wt% to 30 wt%, and the content of impurities such as m-xylene, o-xylene and ethylbenzene is, for example, 70 wt% to 80 wt%.

[0045] Please see Figure 1 As shown, in one embodiment of this utility model, the outlet of the separation unit 12 is also connected to a mother liquor buffer tank 13. Specifically, the inlet of the mother liquor buffer tank 13 is connected to another outlet of the first separator 121. Furthermore, in this embodiment, the outlets of the two first separators 121 are each connected to the inlet of the mother liquor buffer tank 13. The first separator 121 performs solid-liquid separation on the mother liquor flowing out of the crystallization unit 11 and the carried para-xylene crystals. The separated mother liquor enters the mother liquor buffer tank 13 for storage. The temperature of the mother liquor in the mother liquor buffer tank 13 is, for example, -60℃ to -65℃, the para-xylene content in the mother liquor is, for example, 5wt% to 10wt%, and the content of impurities such as m-xylene, o-xylene, and ethylbenzene is, for example, 90wt% to 95wt%.

[0046] Please see Figures 1 to 2As shown, in one embodiment of this utility model, the outlet of the mother liquor buffer tank 13 is connected to an inlet of the mother liquor pump 14 to increase the pressure of the mother liquor flowing out of the mother liquor buffer tank 13, so that the mother liquor can smoothly enter the subsequent subcooler 15. The mother liquor pump 14 is, for example, a centrifugal pump, and includes a pump body 141, a bearing housing 142, a rotating component 143, a pump shaft 144, and a jacket 145. The outlet of the mother liquor buffer tank 13 is connected to the inlet of the pump body 141, and the inlet of the subcooler 15 is connected to the outlet of the pump body 141. The rotating component 143 is disposed inside the pump body 141. Specifically, the mother liquor from the outlet of the mother liquor buffer tank 13 enters the pump body 141, the rotating component 143 rotates, accelerating the mother liquor before it is sent into the subcooler 15. The rotating component 143 is, for example, an impeller.

[0047] Please see Figures 1 to 2 As shown, in one embodiment of this utility model, the bearing housing 142 is disposed on one side of the pump body 141 to accommodate the pump shaft 144. Specifically, one end of the pump shaft 144 is located inside the bearing housing 142, and the other end extends into the pump body 141 and is connected to the rotating component 143.

[0048] Please see Figures 1 to 2 As shown, in one embodiment of this utility model, the mother liquor pump 14 further includes a motor (not shown in the figure). The motor is disposed on the side of the bearing housing 142 away from the pump body 141, and the motor is connected to the end of the pump shaft 144 away from the rotating component 143, so as to drive the pump shaft 144 and the rotating component 143 to rotate sequentially. The motor and the pump shaft 144 are connected, for example, by a coupling (not shown in the figure).

[0049] Please see Figures 1 to 2 As shown, in one embodiment of this utility model, an oil cup 146 is also provided outside the bearing housing 142. The oil cup 146 is connected to the bearing housing 142 to deliver lubricating oil into the bearing housing 142, reducing the resistance to the rotation of the pump shaft 144 and preventing wear of the pump shaft 144. When the mother liquor flows within the pump body 141, its low temperature is easily transferred to the lubricating oil in the bearing housing 142. This lowers the temperature and viscosity of the lubricating oil, hindering the rotation of the pump shaft 144, preventing the rotating component 143 from rotating, and causing the entire mother liquor pump 14 to malfunction. Therefore, it is necessary to heat the lubricating oil in the bearing housing 142 to prevent the low temperature within the bearing housing 142 from affecting the normal operation of the mother liquor pump 14.

[0050] Please see Figures 1 to 2 As shown, in one embodiment of the present invention, a jacket 145 is disposed around a bearing housing 142 between a pump body 141 and a bearing housing 142, and the jacket 145 and the bearing housing 142 are disposed on the same side of the pump body 141.

[0051] Please see Figures 1 to 2As shown, in one embodiment of this utility model, the outlet of the industrial air input pipe 18 and the outlet of the mother liquor buffer tank 13 are each connected to the inlet of the mother liquor pump 14. Specifically, the outlet of the industrial air input pipe 18 is connected to the inlet of the jacket 145, and industrial air is input into the jacket 145. The industrial air heats the lubricating oil in the bearing housing 142 to prevent the lubricating oil temperature from being too low and to ensure the normal operation of the mother liquor pump 14. The temperature of the industrial air output from the industrial air input pipe 18 is, for example, 20℃~50℃, and the pressure of the industrial air is, for example, 0.5MPa-1MPa. At least one control valve 181 is provided on the industrial air input pipe 18 to control the smooth flow of industrial air in the industrial air input pipe 18.

[0052] Please see Figures 1 to 2 As shown, in one embodiment of this utility model, the crystallization device further includes a medium transmission pipe 20, and a portion of the industrial air input pipe 18 is arranged around the medium transmission pipe 20 to heat the industrial air in the industrial air input pipe 18, ensuring that the industrial air flowing into the jacket 145 can maintain a high temperature, thereby heating the lubricating oil in the bearing housing 142. The medium flowing in the medium transmission pipe 20 is, for example, water vapor, with a temperature of, for example, 100℃-200℃ and a pressure of, for example, 0.1MPa-1.5MPa. At least one switch valve 201 is provided on the medium transmission pipe 20 to control the smooth flow of industrial air in the medium transmission pipe 20.

[0053] Please see Figures 1 to 2 As shown, in one embodiment of this utility model, the inlet of the industrial air output pipe 19 and the inlet of the subcooler 15 are each connected to the outlet of the mother liquor pump 14. Specifically, the inlet of the industrial air output pipe 19 is connected to the outlet of the jacket 145. Industrial air is output from the industrial air input pipe 18 into the jacket 145 to heat the lubricating oil in the bearing housing 142. After being cooled, the industrial air flows out of the jacket 145 from the industrial air output pipe 19. Therefore, there is always a supply of high-temperature industrial air into the jacket 145, which continuously heats the lubricating oil in the bearing housing 142, ensuring the smooth operation of the mother liquor pump 14, extending the service life of the mother liquor pump 14, and thus ensuring the smooth operation of the entire crystallization device and improving the operational stability of the crystallization device.

[0054] Please see Figures 1 to 2As shown, in one embodiment of this invention, one outlet of the mother liquor pump 14 is connected to the supercooler 15. In this embodiment, the inlet of the supercooler 15 is connected to the outlet of the pump body 141. Specifically, after the mother liquor pump 14 delivers the mother liquor to the supercooler 15, the supercooler 15 further cools the mother liquor. The dissolved water in the mother liquor will become supersaturated due to the temperature drop, precipitating out of the mother liquor to form water droplets. This facilitates removal in the subsequent isomerization unit, which catalytically converts impurities such as o-xylene, m-xylene, and ethylbenzene in the mother liquor into p-xylene, thereby improving the economic value of the chemicals. By setting up the supercooler 15, the dissolved water in the mother liquor can be removed before the impurities are catalytically converted, avoiding the influence of water on the catalyst activity. A cooling medium flows through the supercooler 15, exchanging heat with the mother liquor to bring it to a supercooled state. Specifically, the cooling medium includes at least one of ethylene, propylene, and isopentane.

[0055] In summary, this invention provides a crystallization apparatus for paraxylene. By connecting the industrial air inlet and outlet pipes to the jacket of the mother liquor pump, continuous heating of the lubricating oil in the bearing housing of the mother liquor pump can be achieved, preventing low temperatures from affecting the smooth operation of the pump. Furthermore, the paraxylene crystallization apparatus provided by this invention ensures smooth operation and improves the operational stability of the crystallization apparatus.

[0056] Throughout this specification, the terms "one embodiment," "an embodiment," or "a specific embodiment" refer to a particular feature, structure, or characteristic described in connection with an embodiment that is included in at least one embodiment of the present invention, but not necessarily in all embodiments. Therefore, the various representations of the phrases "in one embodiment," "in an embodiment," or "in a specific embodiment" in different places throughout the specification do not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic of any specific embodiment of the present invention may be combined with one or more other embodiments in any suitable manner. It should be understood that other variations and modifications of the embodiments of the present invention described and illustrated herein may be based on the teachings herein and will be considered part of the spirit and scope of the present invention.

[0057] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the utility model involved in this application is not limited to the technical solutions formed by specific combinations of the above-described technical features. It should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this application. Except for the technical features described in the specification, the remaining technical features are known to those skilled in the art. To highlight the innovative features of this utility model, the remaining technical features will not be described further here.

Claims

1. A crystallization apparatus for para-xylene, characterized in that, At least including: Raw material input pipeline; At least one crystallization unit is connected to the raw material input pipeline; At least one separation unit is connected to the outlet of the crystallization unit; A mother liquor buffer tank is connected to one outlet of the separation unit; A mother liquor pump, one inlet of which is connected to the outlet of the mother liquor buffer tank; The subcooler is connected to one outlet of the mother liquor pump; An industrial air inlet duct is connected to another inlet of the mother liquor pump; and An industrial air output pipe is connected to another outlet of the mother liquor pump.

2. The crystallization apparatus of claim 1, wherein The mother liquor pump includes a pump body, the outlet of the mother liquor buffer tank is connected to the inlet of the pump body, and the inlet of the subcooler is connected to the outlet of the pump body.

3. The crystallization apparatus of claim 2, wherein, The mother liquor pump also includes a bearing housing and a jacket, the bearing housing and the jacket being disposed on the same side of the pump body, and the jacket surrounding the bearing housing.

4. The crystallization apparatus according to claim 3, characterized in that, The outlet of the industrial air inlet pipe is connected to the inlet of the jacket, and the inlet of the industrial air outlet pipe is connected to the outlet of the jacket.

5. The crystallization apparatus according to claim 1, characterized in that, The crystallization apparatus also includes a medium transmission pipeline, and a portion of the industrial air input pipeline is arranged around the medium transmission pipeline.

6. The crystallization apparatus according to claim 1, characterized in that, The separation unit includes a first separator, the inlet of which is connected to the outlet of the crystallization unit, and one outlet of the first separator is connected to the inlet of the mother liquor buffer tank.

7. The crystallization apparatus according to claim 6, characterized in that, The separation unit also includes a re-slurry tank, the inlet of which is connected to another outlet of the first separator.

8. The crystallization apparatus according to claim 7, characterized in that, The separation unit further includes a second separator, the inlet of which is connected to the outlet of the heavy slurry tank.

9. The crystallization apparatus according to claim 8, characterized in that, The crystallization apparatus also includes a recovery liquid buffer tank, the inlet of which is connected to the outlet of the second separator.

10. The crystallization apparatus according to claim 9, characterized in that, The crystallization apparatus also includes an isomerization reaction system, the inlet of which is connected to the outlet of the recovery liquid buffer tank.

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