Efficient venturi continuous crystallization system

Abstract

The utility model discloses a high-efficiency venturi continuous crystallization system which comprises an Ostland crystallizer, a venturi crystal mixer, a forced circulation pump and a crystal discharge pump, wherein the inlet end of the forced circulation pump is connected with a clear liquid circulation outlet of the Ostland crystallizer through a pipeline I; the outlet end of the forced circulation pump is connected with a clear liquid circulation inlet of the venturi crystal mixer through a pipeline II, and a mixed crystal slurry outlet of the venturi crystal mixer is connected with a circulation liquid inlet of the Ostland crystallizer through a pipeline III; a crystal slurry circulating outlet of the Ostland crystallizer is connected with a crystal slurry inlet of the Venturi crystal mixer through a pipeline IV; an inlet end of the crystal discharge pump is connected with a refined slurry outlet of the Ostland crystallizer through a pipeline V; generation of system seed crystals is effectively controlled, the number of system crystals is controlled, and growth of particles is better facilitated. Therefore, under the condition of the same specification, the crystal particles can be made larger, and the productivity is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of evaporation crystallization, in particular to a high-efficiency Venturi continuous crystallization system. Background Technique

[0002] An evaporation crystallizer is a device that utilizes evaporation and flash evaporation of part of the solvent to achieve supersaturation of the solution, and then forms the required solid precipitate to achieve the purpose of separation and purification. This process equipment is widely used in the evaporation crystallization of water or organic solvent solutions in industries such as medicine, food, chemical engineering, and light industry.

[0003] Currently, conventional crystal crystallizers use FC type crystallizers, DTB type crystallizers or batch kettle crystallizers. Their common feature is that the particle size distribution of the product particles is wide, and it is impossible to screen the product within an effective particle size range at one time, resulting in unstable operation of subsequent separation and drying equipment. At the same time, the re-dissolution amount of fine salt is large, which further reduces the production efficiency.

[0004] To solve the above problems, continuous crystallizers mostly adopt the Oslo form. Through the form of clear liquid circulation, the superheated solution forms a supersaturated solution after flash evaporation, and then circulates through the central circulation pipe to the bottom of the Oslo crystallizer to interact with the crystal particles to finally form large-grained salt. However, since the process adopts clear liquid circulation, the required solution supersaturation is relatively low, resulting in a large equipment volume, high investment and energy consumption, and low crystallization efficiency and production capacity. Based on this, the utility model proposes a high-efficiency Venturi continuous crystallization system that can solve the above problems. Content of the Utility Model

[0005] The purpose of the utility model is to provide a high-efficiency Venturi continuous crystallization system to solve the problems raised in the above background technique.

[0006] To achieve the above purpose, the utility model provides the following technical solution: A high-efficiency Venturi continuous crystallization system includes an Oslo crystallizer, a Venturi crystal mixer, a forced circulation pump, and a crystallization discharge pump;

[0007] The inlet end of the forced circulation pump is connected to the clear liquid circulation outlet of the Oslo crystallizer through pipeline one, the outlet end of the forced circulation pump is connected to the clear liquid circulation inlet of the Venturi crystal mixer through pipeline two, the mixed crystal slurry outlet of the Venturi crystal mixer is connected to the circulating liquid inlet of the Oslo crystallizer through pipeline three, and the crystal slurry circulation outlet of the Oslo crystallizer is connected to the crystal slurry inlet of the Venturi crystal mixer through pipeline four;

[0008] The inlet end of the crystallization discharge pump is connected to the refined slurry flow outlet of the Oslo crystallizer through pipeline five;

[0009] Among them, the second pipeline is connected with a saturated solution inlet pipe, and a feed regulating valve is installed on the second pipeline.

[0010] As a preferred technical solution, the Oslo crystallizer includes, from bottom to top, a crystal product separation zone, a crystal growth and classification zone, a clear liquid separation zone, a superheated dissolution and mixing zone, and a gas-liquid separation zone.

[0011] As a preferred technical solution, the Venturi crystal mixer includes, from top to bottom, an inlet straight tube section, a conical contraction section, a cylindrical waiting tube section, and a conical diffusion section.

[0012] As a preferred technical solution, the feed regulating valve is interlocked with the liquid level of the Oslo crystallizer.

[0013] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0014] Medium-sized crystals inside the Oslo crystallizer can be selectively involved in the flash evaporation cycle, enabling the timely release of superheat, greatly improving the crystallization efficiency. Moreover, since there are almost no fine grains involved, the generation of crystal seeds in the system is effectively controlled, and the number of crystals in the system is controlled, making it more conducive to the growth of particles. Therefore, under the same specifications, the crystal particles can be made larger, improving the production capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic diagram of the overall structure of the present utility model;

[0016] Figure 2 is a schematic diagram of the structure of the Oslo crystallizer of the present utility model;

[0017] Figure 3 is a schematic diagram of the structure of the Venturi crystal mixer of the present utility model;

[0018] In the figure: 10. Oslo crystallizer; 101. Gas-liquid separation zone; 102. Superheated dissolution and mixing zone; 103. Clear liquid separation zone; 104. Crystal growth and classification zone; 105. Crystal product separation zone; 11. First pipeline; 12. Fourth pipeline; 13. Fifth pipeline; 20. Venturi crystal mixer; 201. Inlet straight tube section; 202. Conical contraction section; 203. Cylindrical waiting tube section; 204. Conical diffusion section; 21. Third pipeline; 30. Forced circulation pump; 31. Second pipeline; 32. Saturated solution inlet pipe; 33. Feed regulating valve; 40. Crystallization discharge pump. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0020] Please refer to Figures 1-3 , and a high-efficiency Venturi continuous crystallization system is provided to solve the problem that most of the currently used continuous crystallizers adopt the Oslo form. Through the form of clear liquid circulation, the superheated solution forms a supersaturated solution after flash evaporation, and then circulates through the central circulation pipe to the bottom of the Oslo crystallizer to interact with crystal particles to finally form large-grained salt. However, since the process adopts clear liquid circulation, the required solution supersaturation is relatively low, resulting in a large equipment volume, high investment and energy consumption, and low crystallization efficiency and production capacity. The specific embodiments are as follows:

[0021] Embodiment 1

[0022] The Oslo crystallizer 10 from bottom to top is successively a crystal product separation area 105, a crystal growth and classification area 104, a clear liquid separation area 103, a superheated dissolution and mixing area 102, and a gas-liquid separation area 101.

[0023] The Venturi crystal mixer 20 from top to bottom is successively an inlet straight tube section 201, a conical contraction section 202, a cylindrical waiting tube section 203, and a conical diffusion section 204.

[0024] The inlet end of the forced circulation pump 30 is connected to the clear liquid circulation outlet of the Oslo crystallizer 10 through a pipeline 11, the outlet end of the forced circulation pump 30 is connected to the clear liquid circulation inlet of the Venturi crystal mixer 20 through a pipeline 31, the mixed crystal slurry outlet of the Venturi crystal mixer 20 is connected to the circulating liquid inlet of the Oslo crystallizer 10 through a pipeline 21, and the crystal slurry circulation outlet of the Oslo crystallizer 10 is connected to the crystal slurry inlet of the Venturi crystal mixer 20 through a pipeline 12.

[0025] The gas pipeline at the top of the Oslo crystallizer 10 is connected to the vacuum system, and the inlet end of the crystallization discharge pump 40 is connected to the refined slurry outlet of the Oslo crystallizer 10 through a pipeline 13.

[0026] The pipeline 31 is connected with a saturated solution inlet pipe 32, and a feed regulating valve 33 is installed on the pipeline 31.

[0027] Embodiment 2

[0028] The Oslo crystallizer 10 from bottom to top is successively a crystal product separation area 105, a crystal growth and classification area 104, a clear liquid separation area 103, a superheated dissolution and mixing area 102, and a gas-liquid separation area 101.

[0029] The Venturi crystal mixer 20 successively includes an inlet straight tube section 201, a conical contraction section 202, a cylindrical waiting tube section 203, and a conical diffusion section 204 from top to bottom.

[0030] The inlet end of the forced circulation pump 30 is connected to the clear liquid circulation outlet of the Oslo crystallizer 10 through a first pipeline 11, the outlet end of the forced circulation pump 30 is connected to the clear liquid circulation inlet of the Venturi crystal mixer 20 through a second pipeline 31, the mixed crystal slurry outlet of the Venturi crystal mixer 20 is connected to the circulating liquid inlet of the Oslo crystallizer 10 through a third pipeline 21, and the crystal slurry circulation outlet of the Oslo crystallizer 10 is connected to the crystal slurry liquid inlet of the Venturi crystal mixer 20 through a fourth pipeline 12.

[0031] The gas pipeline at the top of the Oslo crystallizer 10 is connected to the vacuum system, and the inlet end of the crystal discharging pump 40 is connected to the refined slurry flow outlet of the Oslo crystallizer 10 through a fifth pipeline 13.

[0032] A saturated solution inlet pipe 32 is connected to the second pipeline 31, and a feed regulating valve 33 is installed on the second pipeline 31; the feed regulating valve 33 is interlocked with the liquid level of the Oslo crystallizer 10 to ensure the stability of the system liquid level.

[0033] Working principle:

[0034] The material in the clear liquid separation area 103 of the Oslo crystallizer 10 is first mixed with the high-temperature raw material conveyed by the saturated solution inlet pipe 32 through the forced circulation pump 30. Because the temperature of the mixed liquid increases, the fine crystal seeds in the clear liquid are eliminated, and then it is mixed with the medium-sized crystals of 0.2 - 0.5 mm in the Oslo crystallizer 10 by the Venturi crystal mixer 20;

[0035] The mixed crystal slurry is conveyed through the third pipeline 21 to the gas-liquid separation area 101 at the upper part of the Oslo crystallizer 10 for flash evaporation. The superheated crystal-containing solution becomes supersaturated crystal slurry and grows on the existing crystals, and then is pumped to the bottom through the central circulation pipeline in the middle. Due to the density difference formed by the difference in crystal particle size, in the upward liquid flow, the larger crystals have a greater density. Under the action of gravity and the dynamic force of the upward fluid, a balance is finally reached. Among them, the larger particles are suspended near the lower part of the crystallizer, and the smaller crystals are suspended in the middle and upper parts. The large particles of 0.6 - 1.5 mm at the bottom are discharged through the refined slurry flow outlet and can be separated to obtain the required product;

[0036] Among them, the medium-sized particles of 0.2 - 0.5 mm near the lower part enter the Oslo crystallizer 10 to participate in the circulating crystallization process after the solution at the crystal slurry circulation outlet and the clear liquid circulation outlet converge;

[0037] Optionally, medium-sized crystals inside the Oslo crystallizer 10 are involved in the flash evaporation cycle, enabling timely release of the superheat degree, greatly improving the crystallization efficiency. Moreover, since there is almost no participation of fine grains, the generation of crystal seeds in the system is effectively controlled, and the number of crystals in the system is controlled, making it more conducive to the growth of particles. Therefore, under the same specifications, the crystal particles can be made larger, improving the production capacity.

[0038] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An efficient Venturi continuous crystallization system, characterized in that, It includes an Oslo crystallizer (10), a Venturi crystal mixer (20), a forced circulation pump (30), and a crystallization discharge pump (40); The inlet end of the forced circulation pump (30) is connected to the clear liquid circulation outlet of the Oslo crystallizer (10) through a first pipeline (11). The outlet end of the forced circulation pump (30) is connected to the clear liquid circulation inlet of the Venturi crystal mixer (20) through a second pipeline (31). The mixed crystal slurry outlet of the Venturi crystal mixer (20) is connected to the circulating liquid inlet of the Oslo crystallizer (10) through a third pipeline (21). The crystal slurry circulation outlet of the Oslo crystallizer (10) is connected to the crystal slurry inlet of the Venturi crystal mixer (20) through a fourth pipeline (12); The inlet end of the crystallization discharge pump (40) is connected to the refined slurry flow outlet of the Oslo crystallizer (10) through a fifth pipeline (13); Wherein, the second pipeline (31) is connected with a saturated solution inlet pipe (32), and a feed regulating valve (33) is installed on the second pipeline (31).

2. The high-efficiency Venturi continuous crystallization system according to claim 1, characterized in that The Oslo crystallizer (10) successively includes a crystal product separation area (105), a crystal growth classification area (104), a clear liquid separation area (103), a superheated dissolution mixing area (102), and a gas-liquid separation area (101) from bottom to top.

3. An efficient Venturi continuous crystallization system according to claim 1, characterized in that, The Venturi crystal mixer (20) successively includes an inlet straight tube section (201), a conical contraction section (202), a cylindrical waiting tube section (203), and a conical diffusion section (204) from top to bottom.

4. An efficient Venturi continuous crystallization system according to claim 1, characterized in that, The feed regulating valve (33) is interlocked with the liquid level of the Oslo crystallizer (10).

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