Apparatus for continuous crystallization of large particles of 4,4'-difluorobenzophenone

Abstract

This utility model relates to equipment for the continuous crystallization production of large-particle 4,4'-difluorobenzophenone, belonging to the field of crystallization technology. It solves the technical problems of uneven particle size, insufficient purity, low crystallization efficiency, and discontinuous process in the existing industrial production of 4,4'-difluorobenzophenone. The solution is as follows: equipment for the continuous crystallization production of large-particle 4,4'-difluorobenzophenone, including: a dissolving kettle, the inlet of which is connected to a feed pipeline; a crystallization kettle for crystallizing, particle size classification, and controlling fine crystals; several fine crystal overflow ports of different heights and sizes are provided at the top right side of the crystallization kettle; the inlet of a crystal elimination kettle is connected to the fine crystal overflow ports via a crystal elimination pump, and the outlet of the crystal elimination kettle is connected to the reflux port of the dissolving kettle via a reflux pump; a heat exchanger is used to cool the circulating material outside the crystallization kettle. Compared with the prior art, this utility model has the advantages of continuous crystallization production, particle size classification, improved efficiency, and high purity.

Description

Technical Field

[0001] This utility model belongs to the field of crystallization technology, specifically relating to equipment for continuous crystallization production of large-particle 4,4'-difluorobenzophenone. Background Technology

[0002] 4,4'-Difluorobenzophenone is an important organic chemical raw material widely used in industrial fields. It serves not only as a key monomer in the preparation of high-performance engineering plastics such as polyether ether ketone (PEEK) and polyarylether ketone (PAEK), but also in the synthesis of pharmaceutical and pesticide intermediates. It plays an indispensable role in these fields, determining the performance and purity of subsequent products.

[0003] Therefore, the industrial production of 4,4'-difluorobenzophenone in the market demands extremely stringent requirements for product quality and production efficiency. The market requires 4,4'-difluorobenzophenone products with uniform particle size and high purity to meet the needs of subsequent high-performance plastic synthesis. However, existing production methods often suffer from poor reaction dispersion due to uneven particle size, or the introduction of impurities due to insufficient purity, affecting the final product performance. Furthermore, the current production methods for 4,4'-difluorobenzophenone in the market also suffer from low crystallization efficiency and discontinuous processes, failing to meet the demands for large-scale, high-efficiency production. Utility Model Content

[0004] In order to overcome the shortcomings of the existing technology and solve the technical problems such as uneven particle size, insufficient purity, low crystallization efficiency and discontinuous process in the industrial production of 4,4'-difluorobenzophenone, this utility model provides equipment for continuous crystallization production of large-particle 4,4'-difluorobenzophenone.

[0005] This utility model is achieved through the following technical solution.

[0006] This invention provides equipment for the continuous crystallization production of large-particle 4,4'-difluorobenzophenone, comprising: A dissolving vessel, used for high-temperature dissolution to prepare a high-temperature solution, wherein the inlet of the dissolving vessel is connected to a feed pipeline; A crystallization vessel is provided, with its inlet connected to the outlet of a dissolving vessel via a feed pump. The crystallization vessel is used for crystallizing materials, particle size classification, and controlling fine crystals. The crystallization vessel includes a vessel body and a guide tube. The vessel body and the guide tube, located within the vessel body's interior, are coaxially arranged, with the top of the guide tube connected to the top wall of the vessel body. A heat exchange interface is located at the top left side of the vessel body, and several fine crystal overflow ports of varying heights are located at the top right side of the vessel body. The crystal-eliminating reactor has its inlet connected to a fine crystal overflow outlet via a crystal-eliminating pump, and its outlet connected to a reflux outlet of a dissolving reactor via a reflux pump; the crystal-eliminating reactor is used to eliminate fine crystals. The heat exchanger has a heat medium inlet connected to a heat exchange interface via an axial flow pump, a heat medium outlet connected to the feed inlet of the crystallizer, a cold medium inlet at the bottom of the side wall of the heat exchanger, and a cold medium outlet at the top of the side wall of the heat exchanger. The heat exchanger is used to cool the circulating material outside the crystallizer.

[0007] Furthermore, the high-temperature dissolution refers to dissolution at 50°C.

[0008] Furthermore, the dissolving vessel and the crystal-eliminating vessel have the same structure. Both the dissolving vessel and the crystal-eliminating vessel include a stirring shaft, stirring blades and a drive motor. The stirring shaft is located inside the cavity of the dissolving vessel or the crystal-eliminating vessel. The top end of the stirring shaft is connected to the extended end of the drive motor. Stirring blades are evenly distributed at the bottom end of the stirring shaft. Both the dissolving vessel and the crystal-eliminating vessel have steam inlets at the top of their side walls and condensate outlets at the bottom of their side walls.

[0009] Furthermore, both the dissolving vessel and the crystallizing vessel are equipped with jackets.

[0010] Furthermore, the bottom of the inner cavity of the crystallization vessel has a domed structure.

[0011] Furthermore, the height of the fine crystal overflow port is set according to the circulation flow rate and the product particle size.

[0012] Furthermore, it also includes a circulation pump, the inlet and outlet of which are connected to the bottom of the side wall of the crystallizer.

[0013] Furthermore, it also includes a thickener, a centrifuge, and a mother liquor tank. The inlet of the thickener is connected to the outlet of the crystallization vessel, and the outlet of the thickener is connected to the inlet of the centrifuge. The mother liquor separated by the centrifuge is transported to the mother liquor tank through a pipeline.

[0014] The beneficial effects achieved by this utility model are as follows: This utility model uses a crystallization kettle, a guide tube, and a fine crystal overflow port to achieve the effects of directional flow guidance + sedimentation classification + circulation speed control. The axial flow pump draws the supernatant from the heat exchange interface, and after being cooled by the heat exchanger, it continues to flow downwards along the guide tube from the feed inlet of the crystallization kettle, forming a directional flow. When the guide tube guides the flow downwards, the large particles of 4,4'-difluorobenzophenone, due to their faster settling speed, will detach from the downward flow and aggregate to the bottom. The fine crystals, due to their slower settling speed, will flow upwards with the liquid until they are drawn into the crystal elimination kettle by the crystal elimination pump at the fine crystal overflow port, thus realizing the sedimentation of large particles and the classification of fine particles. The grading effect of crystal extraction and clear liquid circulation improves product purity; the height of the fine crystal overflow port is set according to the circulation flow rate and product particle size to enhance applicability; a heat exchanger with a relatively large heat exchange area is selected, eliminating the need for complex heat exchange structures inside the crystallization vessel and reducing the overall equipment footprint; a circulation pump is used to effectively prevent solid deposition, avoid outlet blockage, reduce equipment maintenance frequency, and improve crystallization efficiency; this invention enables continuous crystallization production, improving production efficiency; at the same time, through mother liquor recovery and fine crystal reflux, the raw material utilization rate is high, the degree of automation is high, and labor and raw material costs are reduced.

[0015] Compared with existing technologies, this invention has advantages such as continuous crystallization production, particle size classification, improved efficiency, and high purity. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model.

[0017] In the diagram: 1. Dissolving vessel; 2. Feed pipeline; 3. Crystallizing vessel; 4. Feed pump; 5. Crystallizing vessel body; 6. Flow guide tube; 7. Heat exchange interface; 8. Fine crystal overflow port; 9. Crystallizer; 10. Crystallizer pump; 11. Reflux pump; 12. Heat exchanger; 13. Heat medium inlet; 14. Axial flow pump; 15. Heat medium outlet; 16. Refrigerant inlet; 17. Refrigerant outlet; 18. Stirring shaft; 19. Stirring blades; 20. Drive motor; 21. Steam inlet; 22. Condensate outlet; 23. Jacket; 24. Circulating pump; 25. Thickener; 26. Centrifuge; 27. Mother liquor tank. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0019] like Figure 1 As shown, the equipment for continuous crystallization to produce large-particle 4,4'-difluorobenzophenone includes: Dissolving vessel 1, which is used for high-temperature dissolution to prepare high-temperature solution, wherein the inlet of the dissolving vessel 1 is connected to the feed pipe 2, and the high-temperature dissolution is 50°C dissolution; A crystallization vessel 3 is provided, with its inlet connected to the outlet of a dissolving vessel 1 via a feed pump 4. The crystallization vessel 3 is used for crystallizing materials, particle size classification, and controlling fine crystals. The crystallization vessel 3 includes a crystallization vessel body 5 and a guide tube 6. The crystallization vessel body 5 and the guide tube 6 located inside the crystallization vessel body 5 are coaxially arranged, and the top of the guide tube 6 is connected to the top wall of the crystallization vessel body 5. A heat exchange interface 7 is provided at the top left side of the crystallization vessel body 5, and several fine crystal overflow ports 8 of different heights and sizes are provided at the top right side of the crystallization vessel body 5. The crystal-eliminating vessel 9 has its inlet connected to the fine crystal overflow port 8 via the crystal-eliminating pump 10, and its outlet connected to the reflux port of the dissolving vessel 1 via the reflux pump 11; the crystal-eliminating vessel 9 is used to eliminate fine crystals. The heat exchanger 12 has a heat medium inlet 13 connected to the heat exchange interface 7 via an axial flow pump 14, a heat medium outlet 15 connected to the feed inlet of the crystallizer 3, a cold medium inlet 16 at the bottom of the side wall of the heat exchanger 12, and a cold medium outlet 17 at the top of the side wall of the heat exchanger 12. The heat exchanger 12 is used to cool the external circulating material of the crystallizer 3.

[0020] Specifically, crude 4,4'-difluorobenzophenone and organic solvent methanol or ethanol are added to the dissolving vessel 1, and the crude product is dissolved at a high temperature of 50°C. The crystallization vessel 3 is selected with a diameter of 1m and a liquid holding volume of 5m³. 3The feed pump 4 has a flow rate of 2 m³ / h and a head of 20-35 m. It is made of stainless steel, which allows it to withstand high temperatures of 50-70℃ and prevent corrosion. The feed pump 4 delivers the crude 4,4'-difluorobenzophenone solution to the crystallization vessel 3. The design of the guide tube 6 and the fine crystal overflow port 8 inside the crystallization vessel 3 achieves the effects of directional flow guidance, sedimentation classification, and circulation speed control. The axial flow pump 14 draws the supernatant from the heat exchange interface 7, cools it through the heat exchanger 12, and then continues to flow downwards along the guide tube 6 from the feed inlet of the crystallization vessel 3, forming a directional flow. As the guide tube 6 guides the flow downwards, large particles of 4,4'-difluorobenzophenone, due to their faster settling speed, will detach from the downward flow and aggregate at the bottom. Fine crystals, due to their slower settling speed, will settle with the material. The liquid flows upwards until it reaches the fine crystal overflow port 8, where it is drawn by the crystal elimination pump 10 to the crystal elimination vessel 9. This achieves a classification effect of large particle sedimentation, fine crystal extraction, and clear liquid circulation, thereby improving product purity. The crystal elimination vessel 9 eliminates the fine crystals overflowing from the crystallization vessel 3, preventing their accumulation. The crystal elimination vessel 9 then returns the crystal-eliminating liquid to the dissolving vessel 1 via the return pump 11, achieving raw material recovery. The return pump 11 has a flow rate of 2 m³ / h and a head of 20-35 m, and is made of stainless steel to resist solvent corrosion. The axial flow pump 14 has a flow rate of 40 m³ / h and a head of 5 m, and is also made of stainless steel to resist crystal slurry abrasion. The axial flow pump 14 primarily circulates the material within the crystallization vessel 3. The crystal elimination pump 10 has a flow rate of 2 m³ / h and a head of 20-35 m, and is also made of stainless steel to resist solvent corrosion. The height of the fine crystal overflow port 8 is set according to the circulation flow rate and product particle size to improve applicability. The heat exchanger 12 has a heat exchange area of ​​20 m². 2 It is relatively large, vertical shell and tube type, made of stainless steel, and does not require a complex heat exchange structure inside the crystallizer 3, thus reducing the overall footprint of the equipment.

[0021] The dissolving vessel 1 and the crystal-eliminating vessel 9 have the same structure. Both the dissolving vessel 1 and the crystal-eliminating vessel 9 include a stirring shaft 18, stirring blades 19, and a drive motor 20. The stirring shaft 18 is located inside the cavity of the dissolving vessel 1 or the crystal-eliminating vessel 9. The top end of the stirring shaft 18 is connected to the extended end of the drive motor 20, and the bottom end of the stirring shaft 18 is evenly distributed with stirring blades 19. The top end of the side wall of both the dissolving vessel 1 and the crystal-eliminating vessel 9 is provided with a steam inlet 21, and the bottom end of the side wall of both the dissolving vessel 1 and the crystal-eliminating vessel 9 is provided with a condensate outlet 22. Both the dissolving vessel 1 and the crystal-eliminating vessel 9 are provided with a jacket 23 on the outside.

[0022] Specifically, in the dissolving vessel 1 and the crystal-eliminating vessel 9, the drive motor 20 drives the stirring shaft 18 to rotate the stirring blades 19, thereby improving the stirring efficiency of the internal liquid. The jacket 23 ensures that the material temperature in the dissolving vessel 1 and the crystal-eliminating vessel 9 remains uniform and stable, avoiding local overheating or overcooling, and improving product quality and reaction efficiency.

[0023] The bottom of the inner cavity of the crystallization vessel body 5 has a rounded arch structure.

[0024] Specifically, the arched structure prevents dead corners from forming at the bottom of the crystallizing vessel 5, thus enabling continuous crystallization.

[0025] The height of the fine crystal overflow port 8 is set according to the circulation flow rate and the product particle size.

[0026] Specifically, Table 1 shows the relationship between the height of the fine crystal overflow port 8 and the circulation flow rate and product particle size. The height of the fine crystal overflow port 8 can be set according to the relationship table.

[0027] Table 1. Relationship between the height of the fine-grained overflow port 8 and the circulation flow rate and product particle size. It also includes a circulation pump 24, the inlet and outlet of which are connected to the bottom of the side wall of the crystallizer 3.

[0028] Specifically, the circulating pump 24 has a flow rate of 5 m³ / h, a head of 8-12 m, and is made of stainless steel to resist wear and corrosion. The circulating pump 24 primarily prevents solid particles from accumulating during the equipment's emptying process, avoiding blockage at the discharge port and ensuring continuous production.

[0029] It also includes a thickener 25, a centrifuge 26, and a mother liquor tank 27. The inlet of the thickener 25 is connected to the outlet of the crystallizing vessel 3, and the outlet of the thickener 25 is connected to the inlet of the centrifuge 26. The mother liquor separated by the centrifuge 26 is transported to the mother liquor tank 27 through a pipeline.

[0030] Specifically, the effective volume of the thickener 25 is 2m³. 3 The centrifuge 26, with dimensions of Φ0.8×2.0m, can increase the solid content of the crystal slurry from 15%-20% to 30%-45%. The centrifuge 26 has a processing capacity of 1-3 m³ / h, a balanced feed rhythm, a separation factor of 1500-1800, and can control solvent residue to ≤8%. The drum is Φ800×400mm, with a rotation speed of 2000-2200 r / min, and is made of corrosion-resistant stainless steel. The mother liquor tank 27 has an effective volume of 5m³. 3 The thickener 25, Φ1.2×5.0m, is vertically installed to save floor space and is made of stainless steel. It delivers the concentrated 4,4'-difluorobenzophenone slurry to the centrifuge 26; the centrifuge 26 then starts centrifugation to separate the 4,4'-difluorobenzophenone product, and the mother liquor is delivered to the mother liquor tank 27, improving raw material utilization.

[0031] The working process of this utility model is as follows: 1) Add crude 4,4'-difluorobenzophenone and organic solvent methanol or ethanol to dissolving vessel 1; raise the temperature to 50°C to fully dissolve the crude 4,4'-difluorobenzophenone at high temperature to form a uniform high-temperature solution. 2) Start the feed pump 4. After dissolution, the high-temperature solution is transported to the crystallization vessel 3 through the feed pump 4. Start the axial flow pump 14 to drive the material in the crystallization vessel 3 to circulate externally for crystallization. 3) Start the heat exchanger 12 and introduce chilled water into the refrigerant inlet 16. When the external circulating material flows through the heat exchanger 12, it is cooled down to 10-30℃. The cooled material returns to the crystallizer 3 to continuously maintain the low temperature environment required for crystallization and promote the growth of large crystal particles. 4) The fine crystals overflowing from the fine crystal overflow port 8 are drawn into the crystal elimination vessel 9 by the crystal elimination pump 10, and the crystal elimination vessel 9 eliminates the fine crystals; 5) The slurry containing large crystal particles is discharged from the bottom outlet of the crystallizer 3 and transported to the thickener 25. The slurry is concentrated in the thickener 25 to increase the solid content. During this process, the circulation pump 24 is turned on to prevent solid particles from depositing and to avoid clogging of the outlet. 6) The concentrated crystal slurry in the thickener 25 is transported to the centrifuge 26, the centrifugation operation is started, and the wet product of 4,4'-difluorobenzophenone and the mother liquor are separated. The mother liquor is transported to the mother liquor tank 27.

[0032] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, modifications can still be made to the embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. Equipment for continuous crystallization production of large-particle 4,4'-difluorobenzophenone, characterized in that: include: Dissolving vessel (1), the dissolving vessel (1) is used for high-temperature dissolution to prepare high-temperature solution, and the inlet of the dissolving vessel (1) is connected to the feed pipe (2). The crystallization vessel (3) has its inlet connected to the outlet of the dissolving vessel (1) via a feed pump (4). The crystallization vessel (3) is used for crystallizing, particle size classification, and controlling fine crystals of materials. The crystallization vessel (3) includes a crystallization vessel body (5) and a guide tube (6). The crystallization vessel body (5) and the guide tube (6) located in the inner cavity of the crystallization vessel body (5) are coaxially arranged. The top of the guide tube (6) is connected to the top wall of the crystallization vessel body (5). A heat exchange interface (7) is provided at the top left side of the crystallization vessel body (5), and several fine crystal overflow ports (8) of different heights and sizes are provided at the top right side of the crystallization vessel body (5). The crystal elimination vessel (9) has its inlet connected to the fine crystal overflow port (8) via a crystal elimination pump (10), and its outlet connected to the reflux port of the dissolving vessel (1) via a reflux pump (11); the crystal elimination vessel (9) is used to eliminate fine crystals. The heat exchanger (12) has a heat medium inlet (13) connected to a heat exchange interface (7) via an axial flow pump (14), and a heat medium outlet (15) connected to the feed inlet of the crystallizer (3). The heat exchanger (12) has a cold medium inlet (16) at the bottom of its side wall and a cold medium outlet (17) at the top of its side wall. The heat exchanger (12) is used to cool the circulating material outside the crystallizer (3).

2. The equipment for continuous crystallization production of large-particle 4,4'-difluorobenzophenone according to claim 1, characterized in that: The high-temperature dissolution refers to dissolution at 50°C.

3. The equipment for continuous crystallization production of large-particle 4,4'-difluorobenzophenone according to claim 1, characterized in that: The dissolving vessel (1) and the crystal-eliminating vessel (9) have the same structure. Both the dissolving vessel (1) and the crystal-eliminating vessel (9) include a stirring shaft (18), stirring blades (19) and a drive motor (20). The stirring shaft (18) is located in the inner cavity of the dissolving vessel (1) or the crystal-eliminating vessel (9). The top end of the stirring shaft (18) is connected to the extended end of the drive motor (20). Stirring blades (19) are evenly distributed at the bottom end of the stirring shaft (18). Both the dissolving vessel (1) and the crystal-eliminating vessel (9) have a steam inlet (21) at the top of their side walls and a condensate outlet (22) at the bottom of their side walls.

4. The equipment for continuous crystallization production of large-particle 4,4'-difluorobenzophenone according to claim 3, characterized in that: Both the dissolving vessel (1) and the crystal-eliminating vessel (9) are equipped with jackets (23).

5. The equipment for continuous crystallization production of large-particle 4,4'-difluorobenzophenone according to claim 1, characterized in that: The bottom of the inner cavity of the crystallization vessel body (5) is an arched structure.

6. The apparatus for continuous crystallization production of large-particle 4,4'-difluorobenzophenone according to claim 1, characterized in that: The height of the fine crystal overflow port (8) is set according to the circulation flow rate and the product particle size.

7. The apparatus for continuous crystallization production of large-particle 4,4'-difluorobenzophenone according to claim 1, characterized in that: It also includes a circulation pump (24), the inlet and outlet of which are connected to the bottom of the side wall of the crystallizer (3).

8. The apparatus for continuous crystallization production of large-particle 4,4'-difluorobenzophenone according to claim 1, characterized in that: It also includes a thickener (25), a centrifuge (26) and a mother liquor tank (27). The inlet of the thickener (25) is connected to the outlet of the crystallizer (3), and the outlet of the thickener (25) is connected to the inlet of the centrifuge (26). The mother liquor separated by the centrifuge (26) is transported to the mother liquor tank (27) through a pipeline.

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