DMT rectifying, crystallizing and filtering device

Abstract

The utility model discloses a DMT rectifying, crystallizing and filtering device which comprises an object placing plate, a heat conduction mechanism, a heat conduction plate, a fixing plate, a reboiler, a rectifier, a storage bin, a methanol dissolver, a crystallizing filter and a methanol discharging bin. The heat conduction mechanism comprises a heating medium heater and a heat conduction pipeline which are respectively fixed on the lower surface of the storage plate, and the heating medium heater and the heat conduction pipeline are connected to form a loop; a heat conducting plate and a fixing plate are fixedly installed on the upper surface of the storage plate, a reboiler and a jacket are fixedly installed on the upper surface of the heat conducting plate, the reboiler is sleeved with the jacket, and an outlet of the reboiler is connected with an inlet of a storage bin through a rectifier; the methanol dissolver is fixedly mounted on the upper surface of the fixing plate, an outlet of the storage bin is connected with the methanol dissolver, the crystallization filter and the methanol discharge bin are connected up and down and are located outside the storage plate, and the methanol dissolver is connected with the crystallization filter. The DMT purification device is low in manufacturing and maintenance cost, high in product collection rate and suitable for DMT purification treatment, and the DMT crystallization quality is guaranteed.

Description

Technical Field

[0001] The utility model belongs to the technical field of distillation crystallization filtering equipment, in particular to a DMT distillation crystallization filtering device. Background Art

[0002] Dimethyl terephthalate (DMT) is a monomer of polyester. It is a colorless orthorhombic crystal. It is soluble in hot ethanol, methanol, ether, and chloroform, but insoluble in water. It is mainly used in the synthesis of polyester fibers, resins, films, polyester paints, and engineering plastics.

[0003] Traditional distillation only distills out liquid and cannot achieve the filtration and purification of DMT from solid-liquid-gas-liquid-solid. Therefore, the traditional device has too many limitations when performing filtration and crystallization purification. In addition, the traditional distillation reactor cannot ensure that the reactor body is completely heated evenly during heating, which affects the product quality.

[0004] Chinese patent (CN214020728U) discloses a DCS control system for a distillation reactor, comprising a reactor, a reflux flow detection device and a DCS control system, wherein a steam pipeline is connected to the lower side wall pipeline of the reactor, a condensate discharge pipeline, a feed pipeline and a liquid discharge pipeline are connected to the flange of the lower side wall of the reactor, a dosing device is connected to the flange of the upper side wall of the reactor, a stirring motor is fixedly arranged in the middle of the upper side wall of the reactor, a tower section is fixedly arranged on the right side of the upper side wall of the reactor, a temperature sensor and a pressure sensor are fixedly arranged in the inner cavity of the reactor, a DCS control system is fixedly arranged on the left side of the reactor, and a reflux flow detection device is connected to the left side wall pipeline of the reactor. Preferably, a pressure gauge is fixedly arranged on the left side of the upper side wall of the reactor, a thermometer and a glass sight glass are fixedly arranged on the right side of the upper side wall of the reactor, a thermal insulation layer is fixedly arranged on the shell of the reactor, a steam control solenoid valve is connected to the left side pipeline of the lower side wall of the reactor, and a condensate discharge pipeline, a feed pipeline and a liquid discharge pipeline are connected to the bottom flange of the reactor. The main functions of this system are: using the DCS control system to effectively record and remotely control operations, improving the recording of temperature, pressure, and control of reflux ratio, making the operation more flexible and timely, and viewing the reaction process in real time through the electronic mirror, effectively realizing remote monitoring of the reaction process, reducing a large amount of sampling and testing work, thereby improving the product collection rate, and using the DCS control system to observe the reaction in real time to reduce sampling and monitoring work. To a certain extent, when the distillation reaction is carried out, the experimenter can use the real-time feedback information from the DCS control system to perform the next operation. Although the use of this advanced technology can realize real-time monitoring and adjustment of the reaction situation and improve the collection rate of the product, the relative manufacturing cost will increase, and using advanced technology to improve the collection rate of the product is not a long-term solution. If the device fails, the maintenance cost will also be quite high.

[0005] In view of this, we propose a DMT distillation crystallization filtration device. Utility Model Content

[0006] The purpose of the utility model is to overcome the deficiencies of the above-mentioned prior art and provide a DMT distillation crystallization filtration device with low manufacturing and maintenance costs and high product collection rate, which can be applied to the purification treatment of DMT and ensure the quality of DMT crystals.

[0007] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0008] A DMT distillation crystallization filtration device comprises a placement plate, a heat conduction mechanism, a heat conduction plate, a fixed plate, a reboiler, a rectifier, a storage bin, a methanol dissolver, a crystallization filter and a methanol discharge bin, wherein the heat conduction mechanism is fixedly mounted on the lower surface of the placement plate, the heat conduction mechanism comprises a heat medium heater and a heat conduction pipeline respectively fixed on the lower surface of the placement plate, the heat medium heater is connected with the heat conduction pipeline to form a loop; the heat conduction plate and the fixed plate are respectively fixedly mounted on the upper surface of the placement plate, the reboiler and the jacket are fixedly mounted on the upper surface of the heat conduction plate, the jacket is arranged outside the reboiler, and the outlet of the reboiler is connected to the inlet of the storage bin through the rectifier; the methanol dissolver is fixedly mounted on the upper surface of the fixed plate, the outlet of the storage bin is connected to the methanol dissolver, the crystallization filter and the methanol discharge bin are connected up and down and are located together outside the placement plate, and the methanol dissolver is connected to the crystallization filter.

[0009] The heat-conducting pipeline is a multi-S-shaped pipeline structure, and the outer wall of the heat-conducting pipeline is in contact with the lower surface of the storage plate.

[0010] One side of the heat medium heater is connected with a liquid inlet pipeline.

[0011] The reboiler comprises a stirring blade, and the stirring blade is installed at the bottom of the inner cavity of the reboiler.

[0012] The top of the reboiler is connected with a feed pipe.

[0013] The storage bin and the methanol dissolver are connected up and down through a liquid conduit.

[0014] The methanol dissolver and the crystallization filter are connected up and down through a feed pipe, and a feed switch is installed on the feed pipe.

[0015] A microfiltration membrane is arranged at the bottom outlet of the crystallization filter.

[0016] The beneficial effects of the utility model are:

[0017] 1. Through the coordinated arrangement of heat conduction plate, heat medium heater, heat conduction wire tube and jacket, and stirring blades, all-round wrapping heating of the reboiler is realized, so that the DMT solid is fully and evenly heated after entering the reboiler, providing quality assurance for filtration and purification, ensuring the smooth progress of subsequent filtration and crystallization, and making the DMT crystals filtered out later belong to the standard quality category.

[0018] 2. The DMT distillation crystallization filtration device is constructed by heat conduction mechanism, reboiler, storage bin, methanol dissolver, crystallization filter, methanol discharge bin and other components, so that the crude DMT solid containing impurities is evaporated after melting into liquid state to remove most impurities, and the methanol dissolver is used to cool, solidify and dissolve the gas-liquid mixed DMT containing impurities after being treated in the storage bin, and then high-purity DMT is precipitated through crystallization filtration. The utility model device has reasonable design, low manufacturing and maintenance costs, high product collection rate, and is suitable for the purification of DMT. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a three-dimensional schematic diagram of the overall structure of the utility model;

[0020] Figure 2 A three-dimensional schematic diagram showing the distribution of the heat conduction mechanism of the utility model;

[0021] Figure 3 This is a schematic diagram of the installation of stirring blades in the reboiler of the utility model;

[0022] Figure 4 This is a schematic diagram of the internal structure of the methanol dissolver of the utility model.

[0023] In the figure: a storage plate 1, a heat medium heater 2, a heat transfer pipeline 3, a liquid inlet pipeline 4, a heat transfer plate 5, a fixed plate 6, a reboiler 7, a stirring fan 8, a jacket 9, a support frame 10, a feed pipe 11, a distillation device 12, a storage bin 13, a bin door 14, a liquid guide pipe 15, a methanol dissolver 16, a feed pipe 17, a feed switch 18, a crystallization filter 19, a microfiltration membrane 20, a methanol discharge bin 21, and support legs 22. DETAILED DESCRIPTION

[0024] The utility model is further described below in conjunction with the accompanying drawings and specific embodiments:

[0025] In this embodiment, the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", etc. are based on the directions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction.

[0026] like Figure 1 As shown, a DMT distillation crystallization filtration device includes a placement plate 1, a heat conduction mechanism, a heat conduction plate 5, a fixed plate 6, a reboiler 7, a distillation device 12, a storage bin 13, a methanol dissolver 16, a crystallization filter 19 and a methanol discharge bin 21. The heat conduction mechanism is fixed on the lower surface of the placement plate 1, and the heat conduction mechanism includes a heat medium heater 2 and a heat conduction pipeline 3 respectively fixed on the lower surface of the placement plate 1, and the heat medium heater 2 is connected to the heat conduction pipeline 3 to form a loop; the heat conduction plate 5 and the heat conduction pipeline 3 are respectively fixed on the upper surface of the placement plate 1. A fixed plate 6, a reboiler 7 and a jacket 9 are fixedly installed on the upper surface of the heat conduction plate 5, the jacket 9 is sleeved outside the reboiler 7, the top of the reboiler 7 is exposed from the jacket 9, and the outlet of the reboiler 7 is connected to the inlet of the storage bin 13 through the distillation device 12; a methanol dissolver 16 is fixedly installed on the upper surface of the fixed plate 6, the outlet of the storage bin 13 is connected to the methanol dissolver 16, the crystallization filter 19 and the methanol discharge bin 21 are connected up and down and are located outside the storage plate 1, and the methanol dissolver 16 is connected to the crystallization filter 19.

[0027] like Figure 1 As shown, one side of the heat medium heater 2 is connected to a liquid inlet pipe 4. Figure 2 As shown, the heat conducting pipeline 3 is a multi-S-shaped pipeline structure, that is, the heat conducting pipeline 3 is formed by connecting multiple sections of S-shaped pipelines; the outer wall of the heat conducting pipeline 3 is in contact with the lower surface of the storage plate 1. The storage plate 1 is made of heat conducting materials such as metal, which acts as a carrier and can be fixedly installed with a heat conduction mechanism on its lower surface. A plurality of support frames 10 are installed on the lower surface of the storage plate 1. The storage plate 1 and the support frames 10 form a vertical frame to install other components. When the new heat medium liquid is transported into the heat medium heater 2 through the liquid inlet pipeline 4, the heat medium is heated to the rated temperature through the heat medium heater 2 and the heat conducting pipeline 3 and circulates and heats in the heat conduction mechanism. When the heat medium flows through the heat conducting pipeline 3, the heat is transferred to the heat conducting plate 5 through the storage plate 1, thereby heating the bottom of the reboiler 7. At the same time, the heat conducting plate 5 will also transfer heat to the jacket 9. The jacket 9 is equipped with a heat conducting wire to ensure that the reboiler 7 is heated evenly, and plays the role of fixing the reboiler 7 and transferring heat to the reboiler 7.

[0028] like Figure 3 As shown, the reboiler 7 includes a stirring blade 8 installed at the bottom of the inner cavity of the reboiler 7. When the stirring blade 8 is driven to rotate, the crude DMT solid input into the reboiler 7 can be stirred to promote the rapid melting and evaporation of DMT. The crude DMT solid comes from the current ethylene glycol alcoholysis of waste polyester textiles to prepare PET, that is, the waste polyester textiles are obtained after alcoholysis, polyester-cotton separation, BHET ester exchange, DMT crystallization, and DMT centrifugal separation, and the crude DMT solid contains impurities.

[0029] The utility model heats the DMT solid in all directions through the heat conducting plate 5 and the jacket 9, and stirs the DMT solid in the reboiler 7 through the stirring of the stirring blades 8 installed in the reboiler 7, so as to achieve the effect of rapid melting and evaporation of the DMT solid in the reboiler 7, which can greatly reduce the overall cost of the device and ensure the filtering quality of the distillation crystallization.

[0030] like Figure 1 As shown, a feed pipe 11 is connected to the top of the reboiler 7. Specifically, one end of the feed pipe 11 is sealed and penetrates into the reboiler 7, and the other end of the feed pipe 11 is connected to an external feeder; the feed pipe 11 serves to transport the crude DMT solid raw material into the reboiler 7.

[0031] like Figure 1 As shown, the reboiler 7 and the methanol dissolver 16 are both arranged below the storage bin 13; the storage bin 13 and the methanol dissolver 16 are connected up and down by a liquid guide tube 15, and a bin door 14 is provided on the top of the storage bin 13. When the impure solid DMT is melted and evaporated by the reboiler 7 and processed by the rectifier 12, the evaporated gaseous substance enters the storage bin 13 for storage; the setting of the storage bin 13 realizes the storage and partial liquefaction of the DMT vapor. A backflow prevention device is provided at the connection between the rectifier 12 and the storage bin 13, which can prevent the vapor of the storage bin 13 from liquefying and flowing back to the reboiler 7 through the rectifier 12, causing problems in the crystallization filtration quality. The setting of the bin door 14 can facilitate the experimenter to check the internal situation of the storage bin 13. The liquid guide tube 15 plays the role of transporting the gas-liquid mixed DMT containing impurities inside the storage bin 13. By setting up the methanol dissolver 16, chilled water can be passed outside the methanol dissolver 16 to cool down the gas-liquid mixed DMT containing impurities and solidify it. After solidification, methanol is added to dissolve it to ensure subsequent crystallization and filtration. The gas-liquid mixed DMT containing impurities is directly cooled and solidified instead of being cooled to a liquid state because if it is cooled to a liquid state, the temperature of the liquid material is still very high, about 140°C, and adding methanol will cause methanol to boil.

[0032] like Figure 1 As shown, the methanol dissolver 16 and the crystallization filter 19 are connected up and down through a feed pipe 17, and a feed switch 18 is installed on the feed pipe 17. Figure 4As shown, a microfiltration membrane 20 is installed at the bottom outlet of the crystallization filter 19. The methanol dissolver 16 is installed on the fixed plate 6, and the upper end of the feed pipe 17 passes through the storage plate 1 and the fixed plate 6 and is connected to the methanol dissolver 16, which plays the role of conveying the material inside the methanol dissolver 16; through the setting of the feed switch 18, the opening and closing of the feed pipe 17 and the flow rate of the material in the feed pipe 17 can be controlled. Through the setting of the crystallization filter 19, the mixed material can be crystallized and filtered; through the setting of the methanol discharge bin 21, the methanol after purification can be collected and processed to prevent the leakage of methanol after purification and filtration, which may cause personal injury to the experimenters.

[0033] Through the setting of the microfiltration membrane 20, the DMT crystals that have been crystallized in the crystallization filter 19 are filtered under reduced pressure, so that methanol can pass through the microfiltration membrane 20 and enter the methanol discharge bin 21, which is convenient for the experimenters to carry out centralized processing and ensure that methanol is not missed. The upper end of the crystallization filter 19 is provided with an openable door, which is convenient for the experimenters to collect the DMT crystals after filtration.

[0034] A plurality of supporting legs 22 are installed at the bottom of the methanol discharge bin 21 , so that the crystallization filter 19 and the methanol discharge bin 21 can be stably installed on one side of the storage plate 1 .

[0035] The process of rectification and crystallization using the DMT rectification, crystallization and filtration device of the utility model is as follows: the crude DMT solid (containing impurities) is first melted into a liquid state in a reboiler and then evaporated. After rectification treatment by the rectifier 12, the gaseous DMT enters the storage bin 13 to be stored and partially liquefied; after this operation, most of the impurities have been removed, and the gas-liquid mixed DMT in the storage bin 13 contains only a small amount of impurities. After that, the gas-liquid mixed DMT enters the methanol dissolver 16 to be cooled and solidified. At this time, DMT and impurities are all turned into solid state, and then methanol is added to dissolve the solid impurities and solid DMT to obtain a liquid mixed material. The liquid mixed material is then crystallized and filtered to precipitate DMT crystals, and the filtered methanol (containing impurities) enters the methanol discharge bin 21 to be collected.

[0036] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the utility model and are not used to limit the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection of the utility model is defined by the attached claims and their equivalents.

Claims

1. A DMT distillation crystallization filtration device, comprising a storage plate (1), a heat conduction mechanism, a heat conduction plate (5), a fixed plate (6), a reboiler (7), a distillation device (12), a storage bin (13), a methanol dissolver (16), a crystallization filter (19) and a methanol discharge bin (21), characterized in that: The lower surface of the storage plate (1) is fixed with a heat conduction mechanism, and the heat conduction mechanism includes a heat medium heater (2) and a heat conduction pipeline (3) respectively fixed on the lower surface of the storage plate (1), and the heat medium heater (2) is connected with the heat conduction pipeline (3) to form a loop; the upper surface of the storage plate (1) is fixed with a heat conduction plate (5) and a fixed plate (6), and the upper surface of the heat conduction plate (5) is fixed with a reboiler (7) and a jacket (9), and the jacket (9) is sleeved outside the reboiler (7), and the outlet of the reboiler (7) is connected to the inlet of the storage bin (13) through a rectifier (12); the upper surface of the fixed plate (6) is fixed with a methanol dissolver (16), and the outlet of the storage bin (13) is connected to the methanol dissolver (16), and the crystallization filter (19) and the methanol discharge bin (21) are connected up and down and are located together outside the storage plate (1), and the methanol dissolver (16) is connected to the crystallization filter (19).

2. A DMT distillation crystallization filtration device according to claim 1, characterized in that: The heat-conducting pipeline (3) is a multi-S-shaped pipeline structure, and the outer wall of the heat-conducting pipeline (3) is in contact with the lower surface of the storage plate (1).

3. A DMT distillation crystallization filtration device according to claim 1, characterized in that: One side of the heat medium heater (2) is connected to a liquid inlet pipe (4).

4. A DMT distillation crystallization filtration device according to claim 1, characterized in that: The reboiler (7) comprises a stirring blade (8), and the stirring blade (8) is installed at the bottom of the inner cavity of the reboiler (7).

5. A DMT distillation crystallization filtration device according to claim 1, characterized in that: The top of the reboiler (7) is connected with a feed pipe (11).

6. A DMT distillation crystallization filtration device according to claim 1, characterized in that: The storage bin (13) and the methanol dissolver (16) are connected vertically via a liquid conduit (15).

7. A DMT distillation crystallization filtration device according to claim 1, characterized in that: The methanol dissolver (16) and the crystallization filter (19) are connected vertically via a feed pipe (17), and a feed switch (18) is installed on the feed pipe (17).

8. A DMT distillation crystallization filtration device according to claim 1, characterized in that: A microfiltration membrane (20) is installed at the bottom outlet of the crystallization filter (19).

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