A crystallization system using a crystal enlargement device

Abstract

The present invention discloses a crystallization system using a crystal enlargement device, comprising a crystallizer body, a demister, a crystal thickening device, a first feeding device, a mother liquor discharge pipe, and an elutriator, wherein the demister is arranged at the top of the crystallizer body, the crystal thickening device is arranged at the bottom of the crystallizer body, and the elutriator is arranged below the crystal thickening device. The first feeding device is connected to the crystallizer body, and the crystal thickening device includes an elutriator and a second feeding device, wherein the elutriator is connected to the second feeding device. The present invention increases the obtained crystal particle size to 250 μm to 400 μm by adding a crystal thickening device and utilizing the elutriator and the second feeding device connected thereto. The present invention can obtain crystallized salt with a small specific surface area, and the present invention can effectively improve the purity of the product.

Description

Technical Field

[0001] The invention relates to a crystallization system using a crystal enlargement device, belonging to the technical field of salt crystallization. Background Art

[0002] At present, in the evaporation crystallization process of high brine treatment, the crystal particle size of the high brine sodium sulfate crystallizer is usually below 50um. The small crystal particle size results in a large crystal specific surface area and the crystal surface is stained with mother liquor. In the subsequent drying process, there will be residual impurities on the surface of the crystallized salt, resulting in low quality of the produced crystallized salt. Summary of the Invention

[0003] The object of the present invention is to provide a crystallization system using a crystal enlargement device, which can increase the crystal particle size, obtain a crystallized salt with a small specific surface area and high purity.

[0004] To solve the above technical problems, the present invention adopts the following technical solution: a crystallization system using a crystal enlargement device, comprising a crystallizer body, a demister, a crystal thickening device, a first feeding device, a mother liquor discharge pipe, and an elutriator. The demister is disposed at the top of the crystallizer body, the crystal thickening device is disposed at the bottom of the crystallizer body, and the elutriator is disposed below the crystal thickening device. The first feeding device is connected to the crystallizer body, and the crystal thickening device includes an elutriator and a second feeding device, the elutriator being connected to the second feeding device. The crystal thickening device effectively reduces the strong agitation of the airflow in the evaporation chamber.

[0005] In the aforementioned crystallization system using a crystal enlargement device, the elutriator includes a circular baffle, an inverted conical guide tube, a cross-shaped vortex eliminator, an annular retaining ring, and a rib. The rib is connected to the crystallizer body. The annular retaining ring is located directly below the crystallizer body. The cross-shaped vortex eliminator is arranged below the annular retaining ring and arranged in the inverted conical guide tube. The circular baffle is suspended from the lower end of the inverted conical guide tube. The cross-shaped vortex eliminator is used to eliminate the vortex transmitted from the evaporation chamber, thereby reducing the interference of the vortex on the fluidized bed in the elutriator. The circular baffle turns the downward-flowing salt slurry radially outward to reduce the downward impact of the salt slurry and prevent harmful interference with the fluidized bed. The salt slurry is introduced into the elutriator through the inverted conical guide tube.

[0006] In the aforementioned crystallization system using a crystal enlargement device, the first feeding device includes a first feeding pipe and a feeding preheater, the first feeding pipe and the feeding preheater are connected, and the feeding preheater is connected to the crystallizer body through a pipeline.

[0007] In the aforementioned crystallization system using a crystal enlargement device, the second feeding device includes a second feed pipe, a first circulation pump and an elutriation feed pipe, one end of the elutriation feed pipe is connected to the mother liquor discharge pipe, and the other end of the elutriation feed pipe is connected to the elutriator, the first circulation pump is arranged on the elutriation feed pipe, and one end of the second feed pipe is connected to the elutriation feed pipe.

[0008] In the aforementioned crystallization system using the crystal enlargement device, the crystallizer body includes an evaporator lower cone, the elutriator is connected to the evaporator lower cone, and the feed preheater is connected to the evaporator lower cone of the crystallizer body through a pipeline.

[0009] The aforementioned crystallization system using a crystal enlargement device also includes a mechanical compressor, a heat exchanger, a second circulation pump, a first heat exchange tube and a second heat exchange tube, wherein the mechanical compressor is connected to the demister, the mechanical compressor is connected to the heat exchanger through a pipeline, the heat exchanger is connected to the crystallizer body through the first heat exchange tube, the heat exchanger is connected to the lower cone of the evaporator through the second heat exchange tube, and the second circulation pump is arranged on the second heat exchange tube.

[0010] In the aforementioned crystallization system utilizing the crystal enlargement device, a circle of small holes is provided on the top surface of the inverted conical guide tube. The washed salt slurry, carrying fine crystals, flows upward along the annular region between the inverted conical guide tube and the elutriator, passes through the circle of small holes, and then bypasses the lower end of the annular retaining ring to enter the evaporation chamber.

[0011] Compared with the prior art, the present invention increases the size of the obtained crystals to 250um to 400um by adding a crystal thickening device and utilizing an elutriator and a second feeding device connected thereto. The present invention can obtain crystalline salt with a small specific surface area, and the present invention can effectively improve the purity of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute an undue limitation to the present invention. In the accompanying drawings:

[0013] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0014] Figure 2 It is a schematic structural diagram of the crystal thickening device of the present invention;

[0015] Figure 3 It is a schematic diagram of the top structure of the crystal thickening device of the present invention.

[0016] Figure markings: 1-crystallizer body, 2-demister, 3-crystal thickening device, 4-first feeding device, 5-second feeding device, 6-circular anti-impact plate, 7-inverted cone guide tube, 8-cross vortex eliminator, 9-annular retaining ring, 10-rib plate, 11-first feeding pipe, 12-feed preheater, 13-second feeding pipe, 14-first circulating pump, 15-elutriation feeding pipe, 16-mother liquor discharge pipe, 17-evaporator lower cone, 18-mechanical compressor, 19-heat exchanger, 20-second circulating pump, 21-first heat exchange tube, 22-second heat exchange tube, 23-elutriation device, 24-small hole, 25-evaporation chamber.

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0019] It should be noted that the terms "first," "second," and the like in the specification and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or apparatus.

[0020] Embodiment 1 of the present invention: A crystallization system using a crystal enlargement device includes a crystallizer body 1, a demister 2, a crystal thickening device 3, a first feeding device 4, a second feeding device 5 and a mother liquor discharge pipe 16, wherein the demister 2 is arranged at the top of the crystallizer body 1, the crystal thickening device 3 is arranged at the bottom of the crystallizer body 1, the first feeding device 4 is connected to the crystallizer body 1, and the crystal thickening device 3 includes a elutriator 23 and a second feeding device 5, and the elutriator 23 is connected to the second feeding device 5.

[0021] Embodiment 2 of the present invention: A crystallization system using a crystal enlargement device comprises a crystallizer body 1, a demister 2, a crystal thickening device 3, a first feeding device 4, a second feeding device 5 and a mother liquor discharge pipe 16, wherein the demister 2 is arranged at the top of the crystallizer body 1, the crystal thickening device 3 is arranged at the bottom of the crystallizer body 1, the first feeding device 4 is connected to the crystallizer body 1, the crystal thickening device 3 comprises an elutriator 23 and a second feeding device 5, and the elutriator 23 is connected to the second feeding device 5. The elutriator 23 comprises a circular anti-collision plate 6, an inverted conical guide tube 7, a cross-shaped vortex eliminator 8, an annular retaining ring 9 and a rib 10, the rib 10 is connected to the crystallizer body 1, the annular retaining ring 9 is located directly below the crystallizer body 3, the cross-shaped vortex eliminator 8 is arranged below the annular retaining ring 8 and arranged in the inverted conical guide tube 7, and the circular anti-collision plate 6 is suspended at the lower end of the inverted conical guide tube 7.

[0022] Embodiment 3 of the present invention: A crystallization system using a crystal enlargement device comprises a crystallizer body 1, a demister 2, a crystal thickening device 3, a first feeding device 4, a second feeding device 5 and a mother liquor discharge pipe 16, wherein the demister 2 is arranged at the top of the crystallizer body 1, the crystal thickening device 3 is arranged at the bottom of the crystallizer body 1, the first feeding device 4 is connected to the crystallizer body 1, the crystal thickening device 3 comprises an elutriator 23 and a second feeding device 5, and the elutriator 23 is connected to the second feeding device 5. The elutriator 23 comprises a circular anti-collision plate 6, an inverted conical guide tube 7, a cross-shaped vortex eliminator 8, an annular retaining ring 9 and a rib 10, the rib 10 is connected to the crystallizer body 1, the annular retaining ring 9 is located directly below the crystallizer body 3, the cross-shaped vortex eliminator 8 is arranged below the annular retaining ring 8 and arranged in the inverted conical guide tube 7, and the circular anti-collision plate 6 is suspended at the lower end of the inverted conical guide tube 7. The first feeding device 4 includes a first feeding pipe 11 and a feeding preheater 12 . The first feeding pipe 11 and the feeding preheater 12 are connected. The feeding preheater 12 is connected to the crystallizer body 1 through a pipeline.

[0023] Embodiment 4 of the present invention: A crystallization system using a crystal enlargement device comprises a crystallizer body 1, a demister 2, a crystal thickening device 3, a first feeding device 4, a second feeding device 5, and a mother liquor discharge pipe 16, wherein the demister 2 is arranged at the top of the crystallizer body 1, the crystal thickening device 3 is arranged at the bottom of the crystallizer body 1, the first feeding device 4 is connected to the crystallizer body 1, the crystal thickening device 3 comprises an elutriator 23 and a second feeding device 5, and the elutriator 23 is connected to the second feeding device 5. The elutriator 23 comprises a circular anti-collision plate 6, an inverted conical guide tube 7, a cross-shaped vortex eliminator 8, an annular retaining ring 9, and a rib 10, the rib 10 being connected to the crystallizer body 1, the annular retaining ring 9 being located directly below the crystallizer body 3, the cross-shaped vortex eliminator 8 being arranged below the annular retaining ring 8 and within the inverted conical guide tube 7, and the circular anti-collision plate 6 being suspended from the lower end of the inverted conical guide tube 7. The first feeding device 4 includes a first feeding pipe 11 and a feeding preheater 12. The first feeding pipe 11 and the feeding preheater 12 are connected. The feeding preheater 12 is connected to the crystallizer body 1 through a pipeline. The second feeding device 5 includes a second feeding pipe 13, a first circulation pump 14 and an elutriation feeding pipe 15. One end of the elutriation feeding pipe 15 is connected to the mother liquor discharge pipe 16, and the other end of the elutriation feeding pipe 15 is connected to the elutriator 23. The first circulation pump 14 is provided on the elutriation feeding pipe 15, and one end of the second feeding pipe 13 is connected to the elutriation feeding pipe 15.

[0024] Embodiment 5 of the present invention: A crystallization system using a crystal enlargement device comprises a crystallizer body 1, a demister 2, a crystal thickening device 3, a first feeding device 4, a second feeding device 5, and a mother liquor discharge pipe 16, wherein the demister 2 is arranged at the top of the crystallizer body 1, the crystal thickening device 3 is arranged at the bottom of the crystallizer body 1, the first feeding device 4 is connected to the crystallizer body 1, the crystal thickening device 3 comprises an elutriator 23 and a second feeding device 5, and the elutriator 23 is connected to the second feeding device 5. The elutriator 23 comprises a circular anti-collision plate 6, an inverted conical guide tube 7, a cross-shaped vortex eliminator 8, an annular retaining ring 9, and a rib 10, the rib 10 being connected to the crystallizer body 1, the annular retaining ring 9 being located directly below the crystallizer body 3, the cross-shaped vortex eliminator 8 being arranged below the annular retaining ring 8 and within the inverted conical guide tube 7, and the circular anti-collision plate 6 being suspended from the lower end of the inverted conical guide tube 7. The first feeding device 4 includes a first feeding pipe 11 and a feeding preheater 12. The first feeding pipe 11 and the feeding preheater 12 are connected, and the feeding preheater 12 is connected to the crystallizer body 1 via a pipeline. The second feeding device 5 includes a second feeding pipe 13, a first circulating pump 14, and an elutriation feeding pipe 15. One end of the elutriation feeding pipe 15 is connected to the mother liquor discharge pipe 16, and the other end of the elutriation feeding pipe 15 is connected to the elutriation device 23. The first circulating pump 14 is provided on the elutriation feeding pipe 15, and one end of the second feeding pipe 13 is connected to the elutriation feeding pipe 15. The crystallizer body 1 includes an evaporator lower cone 17. The elutriation device 23 is connected to the evaporator lower cone 17. The feeding preheater 12 is connected to the evaporator lower cone 17 of the crystallizer body 1 via a pipeline. The crystallization system using the crystal enlargement device also includes a mechanical compressor 18, a heat exchanger 19, a second circulation pump 20, a first heat exchange pipe 21, and a second heat exchange pipe 22. The mechanical compressor 18 is connected to the demister 2, which is connected to the heat exchanger 19 via a pipeline. The heat exchanger 19 is connected to the crystallizer body 1 via the first heat exchange pipe 21, and the heat exchanger 19 is connected to the evaporator lower cone 17 via the second heat exchange pipe 22. The second circulation pump 20 is provided on the second heat exchange pipe 22. A circle of small holes is provided on the top surface of the inverted conical guide tube.

[0025] Working principle of the present invention:

[0026] The lower part of the cone of the evaporation chamber 25 of the crystallization evaporator is provided with an elutriator 23. Figure 1 As shown, this elutriator 23 is cylindrical, with its top opening directly connected to the lower cone 17 of the evaporation chamber and its bottom end formed into a conical or dished end. The elutriant, the salt slurry feed to this effect evaporator, enters from the bottom of the elutriator 23. A ring-shaped baffle 9 with small holes ensures a uniform upward flow of the slurry, fluidizing and suspending the salt crystals within the elutriator 23. The salt slurry, having reached a predetermined particle size, is discharged from the bottom of the elutriator 23. This elutriator 23 has three functions:

[0027] 1. Grading effect

[0028] The upward flow in the elutriator 23 carries the fine crystals back to the evaporation chamber for further growth. They settle only when their settling velocity exceeds the upward velocity of the liquid flow. Adjusting the elutriation slurry flow rate controls the concentration of salt crystals in the evaporator's circulation system and the particle size of the discharged salt slurry. To this end, a flow indicator and regulator for the elutriation liquid flow rate is provided. Using the elutriator 23 results in a relatively coarse and uniform particle size in the discharged salt slurry, facilitating the subsequent crystallization and separation process.

[0029] 2. Washing effect

[0030] The salt slurry in the elutriator 23 is countercurrently washed with low-concentration feed salt slurry, replacing the higher-concentration mother liquor in the salt slurry with the low-concentration feed liquid. This ensures that the countercurrent salt separation operation does not cause backflow of the concentrated salt slurry. The mother liquor in the salt slurry sent to the centrifuge for separation is a low-temperature, low-concentration electrolyte that is easy to filter and wash, resulting in minimal loss of crystallized salt.

[0031] 3. Thickening effect

[0032] After adding the elutriator 23, the concentration of the salt slurry discharged from the evaporator increases, generally reaching 35-50%. When the countercurrent salt separation process is adopted, the concentration of the salt slurry discharged from the final effect evaporator elutriator to the salt recovery process is as high as 50%, which reduces the load of the crystallized salt slurry separation process and improves the efficiency of the separation equipment. A component for the entry of crystal slurry and the outflow of elutriation liquid is added at the upper end of the elutriator 23, which can effectively reduce the interference of the strong agitation and vortex in the evaporation chamber on the fluidized bed in the elutriator. The structure of this component is shown in FIG. Figure 2 The salt slurry in the evaporation chamber 25 is introduced into the elutriator 23 through the inverted conical guide tube 7. A cross-shaped vortex eliminator 8 is installed in the inverted conical guide tube 7 to eliminate the vortex transmitted from the evaporation chamber 25. A circular anti-collision plate 6 is suspended at the lower end of the inverted conical guide tube 7 to turn the downward-flowing salt slurry radially outward, so as to reduce the downward impact of the salt slurry and prevent harmful interference to the product bed. There is a circle of small holes 24 at the upper end of the inverted conical guide tube 7. The elutriation liquid carrying fine crystals flows upward along the annular area between the inverted conical guide tube 7 and the elutriator 23, passes through this circle of small holes 24, and then bypasses the lower end of the annular retaining ring 9 to enter the evaporation chamber 25. After using the present invention, the classification, washing and thickening functions of the elutriator are guaranteed.

Claims

1. A crystallization system using a crystal enlargement device, characterized in that: The invention comprises a crystallizer body (1), a demister (2), a crystal thickening device (3), a first feeding device (4) and a mother liquor discharge pipe (16), wherein the demister (2) is arranged at the top end of the crystallizer body (1), the crystal thickening device (3) is arranged at the bottom end of the crystallizer body (1), the first feeding device (4) is connected to the crystallizer body (1), the crystal thickening device (3) comprises an elutriator (23) and a second feeding device (5), the elutriator (23) is connected to the second feeding device (5); ... 3) includes a circular anti-collision plate (6), an inverted conical guide tube (7), a cross-shaped vortex eliminator (8), an annular retaining ring (9) and a rib plate (10), the rib plate (10) is connected to the crystallizer body (1), the annular retaining ring (9) is located directly below the crystallizer body (1), the cross-shaped vortex eliminator (8) is arranged below the annular retaining ring (9) and is arranged in the inverted conical guide tube (7), and the circular anti-collision plate (6) is suspended at the lower end of the inverted conical guide tube (7); the first feeding device (4) includes a first feeding pipe (11) and a feeding preheater (12), a first feed pipe (11) connected to the feed preheater (12), the feed preheater (12) connected to the crystallizer body (1) through a pipeline; the crystallizer body (1) includes an evaporator lower cone (17), the elutriator (23) is connected to the evaporator lower cone (17), the feed preheater (12) is connected to the evaporator lower cone (17) of the crystallizer body (1) through a pipeline; a circle of small holes (24) is provided on the top end of the inverted conical guide tube (7); the second feed device (5) The elutriation device comprises a second feed pipe (13), a first circulation pump (14) and an elutriation feed pipe (15), one end of the elutriation feed pipe (15) is connected to a mother liquor discharge pipe (16), and the other end of the elutriation feed pipe (15) is connected to an elutriator (23). The first circulation pump (14) is arranged on the elutriation feed pipe (15), and one end of the second feed pipe (13) is connected to the elutriation feed pipe (15). The elutriator (23) is cylindrical, and its top opening is directly connected to the lower cone (17) of the evaporator, and its bottom end is a conical head or a dished head.

2. A crystallization system using a crystal enlargement device according to claim 1, characterized in that: The invention also includes a mechanical compressor (18), a heat exchanger (19), a second circulation pump (20), a first heat exchange pipe (21) and a second heat exchange pipe (22), wherein the mechanical compressor (18) is connected to the demister (2), the mechanical compressor (18) is connected to the heat exchanger (19) through a pipeline, the heat exchanger (19) is connected to the crystallizer body (1) through the first heat exchange pipe (21), the heat exchanger (19) is connected to the evaporator lower cone (17) through the second heat exchange pipe (22), and the second circulation pump (20) is arranged on the second heat exchange pipe (22).

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