Freezing crystallization device and system thereof

Abstract

The utility model provides a freezing crystallization device and a system thereof. When the inner wall of the first heat exchanger is bonded, materials in the first heat exchanger are emptied through the first emptying end of the emptying assembly, and then normal-temperature environment gas is continuously input into the first gas inlet pipe through the gas source assembly, so that the normal-temperature environment gas continuously flows through the first heat exchanger and is exhausted through the exhaust assembly. And a material solution generated by melting in the first heat exchanger is discharged from the first emptying end of the emptying assembly. Similarly, when the inner wall of the second heat exchanger is formed, materials in the second heat exchanger are emptied through the second emptying end of the emptying assembly, and then the normal-temperature environment gas is continuously input into the second gas inlet pipe through the gas source assembly, so that the normal-temperature environment gas continuously flows through the second heat exchanger and is exhausted through the exhaust assembly; and the material solution generated by melting in the second heat exchanger is discharged from the second emptying end of the emptying assembly, so that the knot wall on the inner wall of the heat exchanger can be effectively removed, and meanwhile, the energy consumption of the heat exchanger during removing the knot wall is also reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of lithium battery recycling wastewater treatment, and in particular to a freezing crystallization device and a system thereof. Background Art

[0002] In the lithium battery recycling industry, the extraction of lithium salts will produce a solution containing sodium sulfate and sodium chloride. In order to recycle industrial-grade sodium sulfate products, it is necessary to first use frozen crystallization to separate the sodium sulfate and then carry out subsequent refining.

[0003] At present, this type of refrigeration system mostly chooses the process of external shell and tube heat exchanger of crystallizer and circulation heat exchange of salt solution. Compared with the cooling kettle crystallizer, it has the advantages of high heat exchange efficiency and large processing capacity. The solution temperature in the crystallizer is generally frozen to -5~0℃, so that most of the mirabilite (sodium sulfate decahydrate) is crystallized and separated. When this refrigeration system is in operation, the inner wall of the tube of the external heat exchanger is very easy to form a frozen wall (hereinafter referred to as the wall) composed of mirabilite crystals and ice (water) crystals. The wall will reduce the heat exchange efficiency of the heat exchanger, and the current of the circulating pump will continue to increase. Before exceeding the rated current, the system must be shut down and the tube wall must be cleaned, which also causes the refrigeration system to only run for 2~3 days. Cleaning the wall often requires a large amount of clean water for circulation cleaning, and the salt-containing wastewater generated by cleaning also needs to be treated. The commonly used method for treating salt-containing wastewater is evaporation, which consumes a lot of energy; and when the refrigeration system is shut down, the system needs to be emptied, which will waste some cooling capacity; if hot clean water at 50~70℃ is selected for cleaning in order to improve the cleaning efficiency, a heat source must be provided at the same time.

[0004] For example, the Chinese patent with patent application number CN202021181898.4 proposes a complete set of continuous freezing and crystallization equipment, including interconnected crystallization material side equipment and refrigerant side equipment; the crystallization material side equipment includes a crystallizer and a crystallization circulation pump is arranged on the crystallizer, and also includes an external cooler; the refrigerant side equipment includes a gas-liquid separator and a condenser; the refrigerant inlet of the external cooler is connected to the liquid phase outlet of the gas-liquid separator, and the refrigerant outlet of the external cooler is connected to the steam inlet of the gas-liquid separator; the material inlet of the external cooler is connected to the outlet of the crystallization circulation pump, and the material outlet of the external cooler is connected to the material inlet of the crystallizer; the gas phase outlet of the gas-liquid separator is connected to the compressor, and the compressor is also connected to the gas phase inlet of the condenser; the liquid phase outlet of the condenser is connected to the liquid phase inlet of the gas-liquid separator. The complete set of freezing and crystallization equipment of this patent has high working efficiency, low operating cost and good performance.

[0005] However, the technical solution of the above patent has the following problems:

[0006] When the freezing crystallization device is performing freezing crystallization work, the inner wall of the tube of the external cooler will also be blocked. However, the freezing crystallization device has only one external cooler, which requires the device to be shut down for cleaning, resulting in the freezing crystallization system being unable to operate continuously.

[0007] Therefore, how to make the refrigeration system run continuously and stably and remove the wall buildup on the inner wall of the heat exchanger with low energy consumption is the main problem that needs to be solved urgently. Utility Model Content

[0008] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a freezing crystallization device and a system thereof that can operate continuously and stably and remove the wall deposits on the inner wall of the heat exchanger with low energy consumption.

[0009] The purpose of this disclosure is achieved through the following technical solutions:

[0010] A freezing crystallization device, comprising:

[0011] A feed assembly, one end of which is connected to a wastewater system;

[0012] A crystal separator, wherein the other end of the feed assembly is connected to the feed end of the crystal separator;

[0013] A circulation component, wherein the circulation component comprises a first circulation pump and a second circulation pump, the crystal separator comprises a first pumping end and a second pumping end, the feed end of the first circulation pump is connected to the first pumping end of the crystal separator, and the feed end of the second circulation pump is connected to the second pumping end of the crystal separator;

[0014] A heat exchange component, the heat exchange component includes a first heat exchanger, a second heat exchanger, a first air inlet pipe and a second air inlet pipe, the feed end of the first heat exchanger is connected to the discharge end of the first circulation pump, the feed end of the second heat exchanger is connected to the discharge end of the second circulation pump, the discharge end of the first heat exchanger and the discharge end of the second heat exchanger are both connected to the feed end of the crystallizer, the first heat exchanger is provided with a first refrigerant inlet and a first refrigerant outlet, the second heat exchanger is provided with a second refrigerant inlet and a second refrigerant outlet, the first refrigerant inlet, the first refrigerant outlet, the second refrigerant inlet and the second refrigerant outlet are all connected to a refrigeration system, one end of the first air inlet pipe is connected to the feed end of the first heat exchanger, one end of the second air inlet pipe is connected to the feed end of the second heat exchanger, and the other end of the first air inlet pipe and the other end of the second air inlet pipe are both connected to an air source component;

[0015] An exhaust component, wherein an exhaust end of the exhaust component is respectively connected to a discharge end of the first heat exchanger and a discharge end of the second heat exchanger;

[0016] An emptying component, wherein a first emptying end of the emptying component is communicated with a feed end of the first heat exchanger, and a second emptying end of the emptying component is communicated with a feed end of the second heat exchanger.

[0017] In one embodiment, the feed assembly includes a feed pump, a feed pipe, a liquid receiving tank and a flow guide center cylinder, the liquid inlet end of the feed pump is connected to the wastewater system, one end of the feed pipe is connected to the liquid outlet end of the feed pump, the other end of the feed pipe, the discharge end of the first heat exchanger and the discharge end of the second heat exchanger are all connected to the liquid inlet end of the liquid receiving tank, one end of the flow guide center cylinder is connected to the liquid outlet end of the liquid receiving tank, and the other end of the flow guide center cylinder passes through the feed end of the crystallization separator and extends into the crystallization chamber of the crystallization separator.

[0018] In one embodiment, the exhaust assembly includes a first exhaust branch pipe, a second exhaust branch pipe, an exhaust main pipe and an induced draft fan, one end of the first exhaust branch pipe is connected to the discharge end of the first heat exchanger, one end of the second exhaust branch pipe is connected to the discharge end of the second heat exchanger, and the exhaust main pipe is respectively connected to the other end of the first exhaust branch pipe, the other end of the second exhaust branch pipe and the induced draft fan.

[0019] In one embodiment, the emptying component includes a first emptying branch pipe, a second emptying branch pipe, an emptying pump and an emptying collection tank, one end of the first emptying branch pipe is connected to the feed end of the first heat exchanger, one end of the second emptying branch pipe is connected to the feed end of the first heat exchanger, the other end of the first emptying branch pipe, the other end of the second emptying branch pipe and the discharge end of the crystallization separator are all connected to the liquid inlet end of the emptying pump, and the emptying collection tank is connected to the liquid outlet end of the emptying pump.

[0020] In one embodiment, the emptying assembly further includes an emptying reflux branch pipe, one end of which is connected to the liquid outlet of the emptying pump, and the other end of which is connected to the liquid return end of the crystallizer separator.

[0021] In one embodiment, the freezing crystallization device also includes a slurry extraction component, which includes a slurry extraction pump, a centrifuge and a fine crystal separation tank. The liquid inlet end of the slurry extraction pump is connected to the discharge end of the crystallization separator, the liquid outlet end of the slurry extraction pump is connected to the liquid inlet end of the centrifuge, and the liquid outlet end of the centrifuge is connected to the liquid inlet end of the fine crystal separation tank.

[0022] In one of the embodiments, a slope is formed on the bottom of the fine crystal separation tank, and the fine crystal separation tank is provided with a fine crystal separation plate, and one end of the fine crystal separation plate is arranged on the slope.

[0023] In one embodiment, the slurry extraction pump also includes a fine crystal mother liquor reflux pump and a mother liquor pump, the liquid inlet end of the fine crystal mother liquor reflux pump is connected to the first liquid discharge end of the fine crystal separation tank, the liquid outlet end of the fine crystal mother liquor reflux pump is connected to the liquid inlet end of the feed pump, the liquid inlet end of the mother liquor pump is connected to the second liquid discharge end of the fine crystal separation tank, and the liquid outlet end of the mother liquor pump is connected to the mother liquor collection device.

[0024] In one embodiment, the freezing crystallization device further includes an overflow pipe, one end of which is connected to the overflow port of the crystallization separator, and the other end of which is connected to the liquid inlet end of the fine crystal separation tank.

[0025] A freezing crystallization system comprises the freezing crystallization device described in any one of the above embodiments.

[0026] Compared with the prior art, the present invention has at least the following advantages:

[0027] 1. The wastewater system inputs wastewater into the crystallizer through the feed assembly, and then starts the first circulating pump to make the wastewater of the crystallizer flow through the first heat exchanger. At the same time, the refrigeration assembly inputs refrigerant from the first refrigerant inlet, and then flows back to the refrigeration assembly from the first refrigerant outlet for circulating refrigeration, so that the wastewater flowing through the first heat exchanger can be heat exchanged, and the wastewater can be returned to the crystallizer for freezing and crystallization. Further, after the first heat exchanger performs multiple heat exchange cycles, the inner wall will produce a wall. At this time, the first circulating pump is stopped, and the second circulating pump is started to make the wastewater of the crystallizer flow through the first heat exchanger. At the same time, the refrigeration assembly inputs refrigerant from the second refrigerant inlet, and then flows back to the refrigeration assembly from the second refrigerant outlet for circulating refrigeration, so that the wastewater flowing through the second heat exchanger can be heat exchanged, and the wastewater can be returned to the crystallizer for freezing and crystallization. That is, in the case of wall formation in the heat exchanger, another heat exchanger can be switched for heat exchange operation, so that the effect of continuous operation of the cooling crystallization device can be achieved.

[0028] 2. When the wall of the first heat exchanger is condensed, the material in the first heat exchanger is emptied through the first emptying end of the emptying component, and then the air source component continuously inputs ambient air at room temperature to the first air inlet pipe, so that the ambient air at room temperature continues to flow through the first heat exchanger and is discharged by the exhaust component, and the material solution produced by melting in the first heat exchanger is discharged from the first emptying end of the emptying component. Similarly, when the wall of the second heat exchanger is condensed, the material in the second heat exchanger is emptied through the second emptying end of the emptying component, and then the air source component continuously inputs ambient air at room temperature to the second air inlet pipe, so that the ambient air at room temperature continues to flow through the second heat exchanger and is discharged by the exhaust component, and the material solution produced by melting in the second heat exchanger is discharged from the second emptying end of the emptying component, so that the wall of the inner wall of the heat exchanger can be effectively removed, and at the same time, the energy consumption of the heat exchanger when removing the wall is reduced, and the effect of removing the wall of the inner wall of the heat exchanger with low energy consumption is achieved.

[0029] 3. By controlling the refrigerant temperature output by the refrigeration component, not only the effect of continuous refrigeration cycle in a single crystal separator is achieved, but also the cooling curve and crystal nucleus amount of the crystal separator can be controlled, while also extending the wall forming period of a single heat exchanger, thereby extending the service life of a single heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 This is a schematic diagram of the structure of a freezing crystallization device in one embodiment;

[0032] Figure 2 for Figure 1 A schematic diagram of the partial structure of the freezing crystallization device shown;

[0033] Figure 3 for Figure 1 A schematic diagram of the partial structure of the freezing crystallization device shown;

[0034] Reference numerals: freezing crystallization device 10; feed assembly 100; feed pump 110; feed pipeline 120; liquid receiving tank 130; flow guide center tube 140; crystallization separator 200; circulation assembly 300; first circulation pump 310; second circulation pump 320; heat exchange assembly 400; first heat exchanger 410; first refrigerant inlet 412; first refrigerant outlet 414; second heat exchanger 420; second refrigerant inlet 422; second refrigerant outlet 424; first air inlet pipe 430; second air inlet pipe 440 40; exhaust assembly 500; first exhaust branch pipe 510; second exhaust branch pipe 520; exhaust main pipe 530; induced draft fan 540; emptying assembly 600; first emptying branch pipe 610; second emptying branch pipe 620; emptying pump 630; emptying collection tank 640; emptying reflux branch pipe 650; slurry production assembly 700; slurry production pump 710; centrifuge 720; fine crystal separation tank 730; fine crystal separation plate 7310; fine crystal mother liquor reflux pump 740; mother liquor pump 750; overflow pipe 800. DETAILED DESCRIPTION

[0035] In order to facilitate the understanding of the present disclosure, the present disclosure will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present disclosure are given in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present disclosure more thoroughly and comprehensively understood.

[0036] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present disclosure. The terms used herein in the specification of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0038] See also Figures 1 to 3 In order to better understand the freezing crystallization device 10 of the present disclosure, the freezing crystallization device 10 is further explained below:

[0039] A freezing crystallization device 10 of one embodiment includes a feed assembly 100, a crystal separator 200, a circulation assembly 300, a heat exchange assembly 400, an exhaust assembly 500 and an emptying assembly 600. One end of the feed assembly 100 is communicated with a wastewater system. The other end of the feed assembly 100 is communicated with a feed end of the crystal separator 200. The circulation assembly 300 includes a first circulation pump 310 and a second circulation pump 320, and the crystal separator 200 includes a first pumping end and a second pumping end, the feed end of the first circulation pump 310 is communicated with the first pumping end of the crystal separator 200, and the feed end of the second circulation pump 320 is communicated with the second pumping end of the crystal separator 200. The heat exchange assembly 400 includes a first heat exchanger 410, a second heat exchanger 420, a first air inlet pipe 430 and a second air inlet pipe 440. The feed end of the first heat exchanger 410 is connected to the discharge end of the first circulation pump 310, the feed end of the second heat exchanger 420 is connected to the discharge end of the second circulation pump 320, the discharge end of the first heat exchanger 410 and the discharge end of the second heat exchanger 420 are both connected to the feed end of the crystallizer 200, and the first heat exchanger 410 is provided with a first refrigerant inlet 412 and a first refrigerant outlet 413. 4, the second heat exchanger 420 is provided with a second refrigerant inlet 422 and a second refrigerant outlet 424, the first refrigerant inlet 412, the first refrigerant outlet 414, the second refrigerant inlet 422 and the second refrigerant outlet 424 are all connected to the refrigeration system, one end of the first air inlet pipe 430 is connected to the feed end of the first heat exchanger 410, one end of the second air inlet pipe 440 is connected to the feed end of the second heat exchanger 420, and the other end of the first air inlet pipe 430 and the other end of the second air inlet pipe 440 are both connected to the gas source component. The exhaust end of the exhaust component 500 is respectively connected to the discharge end of the first heat exchanger 410 and the discharge end of the second heat exchanger 420. The first exhaust end of the emptying component 600 is connected to the feed end of the first heat exchanger 410, and the second exhaust end of the emptying component 600 is connected to the feed end of the second heat exchanger 420.

[0040] In this embodiment, the wastewater system inputs the wastewater into the crystallizer separator 200 through the feed component 100, and then starts the first circulation pump 310 to make the wastewater in the crystallizer separator 200 flow through the first heat exchanger 410. At the same time, the refrigeration component inputs the refrigerant from the first refrigerant inlet 412, and then returns to the refrigeration component from the first refrigerant outlet 414 for circulating refrigeration. In this way, heat can be exchanged for the wastewater flowing through the first heat exchanger 410, and the wastewater can be returned to the crystallizer separator 200 for freezing and crystallization. Furthermore, after the first heat exchanger 410 undergoes multiple heat exchange cycles, clots will form on the inner wall. At this time, the first circulation pump 310 is stopped, and the second circulation pump 320 is started to make the wastewater from the crystallizer separator 200 flow through the first heat exchanger 410. At the same time, the refrigeration component inputs refrigerant from the second refrigerant inlet 422, and then the refrigerant flows back to the refrigeration component from the second refrigerant outlet 424 for circulating refrigeration. In this way, heat can be exchanged with the wastewater flowing through the second heat exchanger 420, and the wastewater can flow back to the crystallizer separator 200 for freezing and crystallization. That is, when there is clots in the heat exchanger, another heat exchanger can be switched to perform heat exchange operations, thereby achieving the effect of continuous operation of the cooling crystallization device.

[0041] Furthermore, when a wall buildup appears on the inner wall of the first heat exchanger 410, the material in the first heat exchanger 410 is drained through the first drain end of the drain component 600, and then the air source component continuously inputs ambient gas at normal temperature into the first air inlet pipe 430, so that the ambient gas at normal temperature continues to flow through the first heat exchanger 410 and is discharged through the exhaust component 500, and the material solution produced by melting in the first heat exchanger 410 is discharged from the first drain end of the drain component 600. Similarly, when the second heat exchanger 420 has a condensation on its inner wall, the material in the second heat exchanger 420 is emptied through the second condensation end of the condensation assembly 600, and then the air source assembly continuously inputs ambient gas at normal temperature into the second air inlet pipe 440, so that the ambient gas at normal temperature continues to flow through the second heat exchanger 420 and is discharged by the exhaust assembly 500, and the material solution produced by the melting in the second heat exchanger 420 is discharged from the second condensation end of the condensation assembly 600, thereby effectively removing the condensation on the inner wall of the heat exchanger and reducing the energy consumption when removing the condensation from the heat exchanger, thereby achieving the effect of removing the condensation on the inner wall of the heat exchanger with low energy consumption.

[0042] Furthermore, by controlling the refrigerant temperature output by the refrigeration component, not only the effect of continuous refrigeration cycle is achieved in a single crystal separator 200, but also the cooling curve and the amount of crystal nuclei in the crystal separator 200 can be controlled, while also extending the wall-bonding period of a single heat exchanger, thereby extending the service life of a single heat exchanger.

[0043] It should be noted that by switching back and forth between the first heat exchanger 410 and the second heat exchanger 420, it is ensured that when wall formation occurs in one of the heat exchangers, the other heat exchanger can continue to perform heat exchange operation, thereby achieving the effect of continuous operation of the freezing crystallization device 10.

[0044] It should be noted that both the first circulation pump 310 and the second circulation pump 320 are vertical axial flow circulation pumps; the first air inlet pipe 430 has an upward tilted angle relative to the horizontal plane, and the tilted angle is greater than 30°, so that it can be ensured that the liquid dripping when the inner wall of the first heat exchanger 410 melts will not flow out from the first air inlet pipe 430. Similarly, the second air inlet pipe 440 has an upward tilted angle relative to the horizontal plane, and the tilted angle is greater than 30°, so that it can be ensured that the liquid dripping when the inner wall of the second heat exchanger 420 melts will not flow out from the second air inlet pipe 440.

[0045] like Figure 1 to Figure 2 As shown, in one embodiment, the feed assembly 100 includes a feed pump 110, a feed pipe 120, a liquid receiving tank 130 and a diversion center tube 140, the liquid inlet end of the feed pump 110 is connected to the wastewater system, one end of the feed pipe 120 is connected to the liquid outlet end of the feed pump 110, the other end of the feed pipe 120, the discharge end of the first heat exchanger 410 and the discharge end of the second heat exchanger 420 are all connected to the liquid inlet end of the liquid receiving tank 130, one end of the diversion center tube 140 is connected to the liquid outlet end of the liquid receiving tank 130, and the other end of the diversion center tube 140 passes through the feed end of the crystallization separator 200 and extends into the crystallization chamber of the crystallization separator 200. It should be noted that the wastewater system outputs the wastewater to be treated along the flow of the feed pump 110, the feed pipeline 120, the liquid receiving tank 130 and the flow guide center tube 140 in sequence to the bottom of the crystallizer separator 200, and the bottom of the crystallizer separator 200 is W-shaped, so that crystals of target particle size can be sorted by gravity and viscosity.

[0046] like Figure 1 to Figure 2As shown, in one embodiment, the exhaust assembly 500 includes a first exhaust branch pipe 510, a second exhaust branch pipe 520, an exhaust main pipe 530 and an induced draft fan 540. One end of the first exhaust branch pipe 510 is connected to the discharge end of the first heat exchanger 410, one end of the second exhaust branch pipe 520 is connected to the discharge end of the second heat exchanger 420, and the exhaust main pipe 530 is respectively connected to the other end of the first exhaust branch pipe 510, the other end of the second exhaust branch pipe 520 and the induced draft fan 540. It should be noted that, under the action of the induced draft fan 540, the normal temperature ambient gas in the first heat exchanger 410 is moved along the flow direction of the discharge end of the first heat exchanger 410, the first exhaust branch pipe 510 and the exhaust main pipe 530, and finally discharged by the induced draft fan 540. Similarly, under the action of the induced draft fan 540, the normal temperature ambient gas in the second heat exchanger 420 is moved along the discharge end of the second heat exchanger 420, the second exhaust branch pipe 520 and the exhaust main pipe 530, and is finally discharged by the induced draft fan 540, so that the first heat exchanger 410 or the second heat exchanger 420 can continue to exchange heat with new normal temperature ambient gas, thereby removing the buildup on the inner wall of the first heat exchanger 410 or the second heat exchanger 420, thereby achieving the effect of removing the buildup on the inner wall of the heat exchanger with low energy consumption.

[0047] like Figures 1 to 3 As shown, in one embodiment, the emptying assembly 600 includes a first emptying branch pipe 610, a second emptying branch pipe 620, an emptying pump 630 and an emptying collection tank 640, one end of the first emptying branch pipe 610 is connected to the feed end of the first heat exchanger 410, one end of the second emptying branch pipe 620 is connected to the feed end of the first heat exchanger 410, the other end of the first emptying branch pipe 610, the other end of the second emptying branch pipe 620 and the liquid discharge end of the crystallizer 200 are all connected to the liquid inlet end of the emptying pump 630, and the emptying collection tank 640 is connected to the liquid outlet end of the emptying pump 630. It should be noted that the feed end of the first heat exchanger 410 is located at the bottom of the first heat exchanger 410, and the material in the first heat exchanger 410 can be emptied from the first emptying branch pipe 610 to the emptying collection tank 640 by starting the emptying pump 630. Similarly, the feed end of the second heat exchanger 420 is located at the bottom of the second heat exchanger 420. By starting the emptying pump 630, the material in the second heat exchanger 420 can be emptied from the second emptying branch pipe 620 to the emptying collection tank 640, so that the circulating waste water in the first heat exchanger 410 or the second heat exchanger 420 can be discharged to facilitate the wall cleaning operation of the inner wall of the heat exchanger.

[0048] like Figures 1 to 3As shown, in one embodiment, the emptying assembly 600 further includes an emptying return branch pipe 650, one end of the emptying return branch pipe 650 is connected to the liquid outlet end of the emptying pump 630, and the other end of the emptying return branch pipe 650 is connected to the liquid return end of the crystal separator 200. It should be noted that the wastewater discharged by the emptying pump 630 is returned to the crystal separator 200 through the emptying return branch pipe 650, which can ensure the wastewater treatment rate while avoiding the loss of cold capacity.

[0049] like Figures 1 to 3 As shown, in one embodiment, the freezing crystallization device 10 also includes a slurry extraction component 700, and the slurry extraction component 700 includes a slurry extraction pump 710, a centrifuge 720 and a fine crystal separation tank 730, the liquid inlet end of the slurry extraction pump 710 is connected to the discharge end of the crystallization separator 200, the liquid outlet end of the slurry extraction pump 710 is connected to the liquid inlet end of the centrifuge 720, and the liquid outlet end of the centrifuge 720 is connected to the liquid inlet end of the fine crystal separation tank 730. It should be noted that the conventional freezing crystallization device 10 generally starts to extract the crystal slurry of the suspension section of the crystal separator 200 when the salt solution in the crystal separator 200 drops to -5°C to 0°C during the first startup and cooling process. At this time, the solid-liquid ratio in the crystal separator 200 is 20% to 40%, and the solid-liquid ratio of the suspension section is greater than 40%, which can easily lead to problems such as heavy load and easy blockage of the centrifuge 720, a large amount of fine crystals in the liquid in the upper expansion section of the crystal separator 200, a large current of the circulating pump, rapid wall formation in the heat exchanger, and violent crystal collisions that are prone to secondary nucleation. In this embodiment, the freezing crystallization device 10 disclosed in the present invention is that when the temperature of the salt solution in the crystallizer separator 200 drops to 10-15°C during the first cooling process from >20°C, the solid-liquid ratio of the slurry in the suspended section is >20%. At this time, the slurry is extracted by the slurry extraction pump 710 and centrifuged by the centrifuge 720. The centrifuge 720 is in a normal load state and runs smoothly. At this time, the liquid in the upper expansion section of the crystallizer separator 200 is clear, the fine crystal content is small, the current of the circulation pump is small, the fine crystals flowing through the heat exchanger are small, and the wall formation time is greatly extended, thereby increasing the operating time of a single heat exchanger from 2-3 days to 7-10 days.

[0050] It should be noted that the solid outlet after separation by the centrifuge 720 obtains Glauber's salt or target crystals, the Glauber's salt is re-dissolved, and the target crystals enter the subsequent refining system.

[0051] like Figures 1 to 3As shown, in one embodiment, the bottom of the fine crystal separation tank 730 is formed with an inclined surface, and the fine crystal separation tank 730 is provided with a fine crystal separation plate 7310, and one end of the fine crystal separation plate 7310 is arranged on the inclined surface. It should be noted that the fine crystal separation plate 7310 is in a "human" shape, and the fine crystal separation plate 7310 is provided with a top on the side with a high inclined surface.

[0052] like Figures 1 to 3 As shown, in one embodiment, the crystal slurry extraction pump 710 further includes a fine crystal mother liquor reflux pump 740 and a mother liquor pump, the liquid inlet end of the fine crystal mother liquor reflux pump 740 is connected to the first liquid discharge end of the fine crystal separation tank 730, the liquid outlet end of the fine crystal mother liquor reflux pump 740 is connected to the liquid inlet end of the feed pump 110, the liquid inlet end of the mother liquor pump is connected to the second liquid discharge end of the fine crystal separation tank 730, and the liquid outlet end of the mother liquor pump is connected to the mother liquor collection device. It should be noted that after the crystal slurry is extracted by the first cooling and centrifugation 720, the mother liquor still contains more than 5% sodium sulfate, and the mother liquor is refluxed to the crystal separator 200 through the fine crystal mother liquor reflux pump 740 to continue freezing and crystallization. During the cooling period, the feed pump 110 is used to supplement the liquid level in the crystal separator 200 that is reduced due to the extraction of mirabilite, so that the first circulation pump 310 or the second circulation pump 320 can operate normally. Furthermore, by setting the temperature of the refrigerant in the refrigeration component to decrease in stages as the temperature of the solution in the crystallizer decreases, it is avoided that excessive supersaturation is generated locally, the supersaturated solution is placed in an unstable zone, the number of nuclei is reduced, and the formation of wall formation in the first heat exchanger 410 or the second heat exchanger 420 is delayed until the temperature of the salt solution in the crystallizer separator 200 drops to the target freezing temperature, the supersaturation generated by the feed is balanced with the production, and the liquid in the upper expansion section of the crystallizer can always be kept clear during the process. Thereafter, 5% to 20% of the mother liquor separated by the centrifuge 720 is refluxed to the crystallizer separator 200 by the fine crystal mother liquor reflux pump 740 to recover fine crystals and provide crystal nuclei, and part of the fine crystals are directly eliminated by mixing with the feed at a higher temperature, and 80% to 95% of the mother liquor separated by the centrifuge 720 is transferred by the mother liquor pump to the mother liquor collection device.

[0053] In one embodiment, the temperature control principle of extending the wall bonding time of the first heat exchanger or the second heat exchanger by using the refrigeration component is as follows:

[0054] When sodium chloride is less than 2%, the freezing point of the saline solution is mainly affected by sodium sulfate, and the freezing point is -1°C. The refrigerant temperature at the outlet of the refrigeration component is controlled to be greater than -1°C; when sodium chloride is greater than 2% and less than 12%, the freezing point of the saline solution is mainly affected by sodium chloride, -8°C < freezing point < -1°C. According to the actual freezing point, the refrigerant temperature at the outlet of the refrigeration component is controlled to be greater than the freezing point; when sodium chloride is greater than 12% and less than 25%, the freezing point of the saline solution is mainly affected by sodium chloride, and the freezing point is less than -8°C. The freezing target temperature of the saline solution is controlled to be -5°C, and the refrigerant temperature is greater than the freezing point at this time; when sodium chloride is greater than 25%, the freezing point of the saline solution is mainly affected by sodium chloride, -8°C < freezing point < -1°C. According to the actual freezing point, the refrigerant temperature at the outlet of the refrigeration component is controlled to be greater than the freezing point.

[0055] like Figures 1 to 3 As shown, in one embodiment, the freezing crystallization device 10 further includes an overflow pipe 800, one end of which is connected to the overflow port of the crystal separator 200, and the other end of which is connected to the liquid inlet end of the fine crystal separation tank 730. It can be understood that the overflow pipe 800 is used to prevent the solution in the crystal separator 200 from overflowing and to limit the liquid level.

[0056] See also Figures 1 to 3 In one embodiment, the operation process of the freezing crystallization device 10 is as follows:

[0057] 1. The material solution is pumped to the liquid receiving tank 130 by the feed pump 110. The material solution in the liquid receiving tank 130 flows downward through the central guide tube and out of the bottom of the crystallizer 200, and then flows upward to reach the liquid level at which the first circulation pump 310 can work, and the first circulation pump 310 is started;

[0058] 2. Turn on the refrigeration component, set the target temperature of the refrigerant ethylene glycol-water solution to 10°C, and deliver the refrigerant to the first refrigerant inlet 412 of the first heat exchanger 410 through the outlet of the refrigeration component. The refrigerant then flows back from the first refrigerant outlet 414 of the first heat exchanger 410 to the inlet of the refrigeration component for circulating refrigeration, thereby reducing the temperature of the material solution in the first heat exchanger 410;

[0059] 3. The material dissolving temperature is reduced to 10-15°C, and the target temperature of the refrigerant is set to 5°C. The crystal slurry of the suspension section of the crystal separator 200 is extracted through the crystal slurry extraction pump 710 and enters the centrifuge 720 for centrifugal separation. The mother liquor after centrifugation enters the fine crystal separation tank 730, and the mirabilite crystals enter the re-dissolution-evaporation system;

[0060] 4. At this time, the mother liquor in the fine crystal separation tank 730 still contains more than 5% of sodium sulfate. The fine crystal mother liquor reflux pump 740 refluxes 100% of the mother liquor to the crystallizer separator 200 for continued freezing, and the feed pump 110 continues to feed to maintain the liquid level at which the first circulation pump 310 can work;

[0061] 5. Set the target temperature of the coolant to -1°C, the temperature of the material solution in the crystallizer 200 is reduced to 3°C, and the system reaches a balance between the supersaturation of the feed and the extraction. 5% to 20% of the mother liquor is refluxed to the crystallizer 200 by the fine crystal mother liquor reflux pump 740, and 80% to 95% of the mother liquor after centrifugal separation is transferred to the mother liquor collection device by the mother liquor pump.

[0062] 6. When the current of the first circulation pump 310 reaches 160-180A, the second circulation pump 320 and its brine circulation are turned on, and the first circulation pump 310 and its brine circulation are stopped. The overflow pipe 800 is used to prevent the crystallizer 200 from overflowing due to the change of liquid level during switching, and the freezing crystallization device 10 continues to operate;

[0063] 7. Start the wall regeneration of the first heat exchanger 410, discharge the remaining material solution in the first heat exchanger 410 through the first emptying branch pipe 610, and start the emptying pump 630 to pump the remaining material solution from the emptying reflux branch pipe 650 back to the crystallizer 200;

[0064] 8. Open the valve on the first air inlet pipe 430 of the first heat exchanger 410, open the valve on the first exhaust pipe, turn on the induced draft fan 540, and maintain the negative pressure of the induced draft fan 540 at -100Pa to -20Pa;

[0065] 9. Ambient air with a temperature higher than the crystal temperature of the junction wall is passed through the tube side of the first heat exchanger 410, and the junction wall gradually melts. The duration is 2 days, which varies according to the ambient temperature. A small amount of material solution produced by the melting is discharged from the first drain branch pipe 610 to the drain collection tank 640 through the drain pump 630. After the regeneration is completed, the first heat exchanger 410 enters the standby state.

[0066] The present disclosure also provides a freezing crystallization system, comprising the freezing crystallization device described in any of the above embodiments.

[0067] In this embodiment, the wastewater system inputs wastewater into the crystallizer through the feed assembly, and then starts the first circulation pump to make the wastewater of the crystallizer flow through the first heat exchanger. At the same time, the refrigeration assembly inputs refrigerant from the first refrigerant inlet, and then flows back to the refrigeration assembly from the first refrigerant outlet for circulation refrigeration, so that the wastewater flowing through the first heat exchanger can be heat exchanged, and the wastewater can be returned to the crystallizer for freezing and crystallization. Further, after the first heat exchanger performs multiple heat exchange cycles, the inner wall will produce a wall. At this time, the first circulation pump is stopped, and the second circulation pump is started to make the wastewater of the crystallizer flow through the first heat exchanger. At the same time, the refrigeration assembly inputs refrigerant from the second refrigerant inlet, and then flows back to the refrigeration assembly from the second refrigerant outlet for circulation refrigeration, so that the wastewater flowing through the second heat exchanger can be heat exchanged, and the wastewater can be returned to the crystallizer for freezing and crystallization. That is, in the case of wall formation in the heat exchanger, another heat exchanger can be switched for heat exchange operation, so that the effect of continuous operation of the cooling crystallization system can be achieved.

[0068] Furthermore, when a stagnation appears on the inner wall of the first heat exchanger, the material in the first heat exchanger is emptied through the first emptying end of the emptying component, and then the air source component continuously inputs ambient air at room temperature to the first air inlet pipe, so that the ambient air at room temperature continuously flows through the first heat exchanger and is discharged by the exhaust component, and the material solution produced by melting in the first heat exchanger is discharged from the first emptying end of the emptying component. Similarly, when a stagnation appears on the inner wall of the second heat exchanger, the material in the second heat exchanger is emptied through the second emptying end of the emptying component, and then the air source component continuously inputs ambient air at room temperature to the second air inlet pipe, so that the ambient air at room temperature continuously flows through the second heat exchanger and is discharged by the exhaust component, and the material solution produced by melting in the second heat exchanger is discharged from the second emptying end of the emptying component, so that the stagnation on the inner wall of the heat exchanger can be effectively removed, and at the same time, the energy consumption of the heat exchanger when removing the stagnation is reduced, and the effect of removing the stagnation on the inner wall of the heat exchanger with low energy consumption is achieved.

[0069] Furthermore, by controlling the temperature of the refrigerant output by the refrigeration component, not only the effect of continuous refrigeration cycle is achieved in a single crystal separator, but also the cooling curve and the amount of crystal nuclei of the crystal separator can be controlled, while also extending the wall-bonding period of a single heat exchanger, thereby extending the service life of a single heat exchanger.

[0070] Compared with the prior art, the present invention has at least the following advantages:

[0071] 1. The wastewater system inputs wastewater into the crystallizer through the feed assembly, and then starts the first circulating pump to make the wastewater of the crystallizer flow through the first heat exchanger. At the same time, the refrigeration assembly inputs refrigerant from the first refrigerant inlet, and then flows back to the refrigeration assembly from the first refrigerant outlet for circulating refrigeration, so that the wastewater flowing through the first heat exchanger can be heat exchanged, and the wastewater can be returned to the crystallizer for freezing and crystallization. Further, after the first heat exchanger performs multiple heat exchange cycles, the inner wall will produce a wall. At this time, the first circulating pump is stopped, and the second circulating pump is started to make the wastewater of the crystallizer flow through the first heat exchanger. At the same time, the refrigeration assembly inputs refrigerant from the second refrigerant inlet, and then flows back to the refrigeration assembly from the second refrigerant outlet for circulating refrigeration, so that the wastewater flowing through the second heat exchanger can be heat exchanged, and the wastewater can be returned to the crystallizer for freezing and crystallization. That is, in the case of wall formation in the heat exchanger, another heat exchanger can be switched for heat exchange operation, so that the effect of continuous operation of the cooling crystallization device can be achieved.

[0072] 2. When the wall of the first heat exchanger is condensed, the material in the first heat exchanger is emptied through the first emptying end of the emptying component, and then the air source component continuously inputs ambient air at room temperature to the first air inlet pipe, so that the ambient air at room temperature continues to flow through the first heat exchanger and is discharged by the exhaust component, and the material solution produced by melting in the first heat exchanger is discharged from the first emptying end of the emptying component. Similarly, when the wall of the second heat exchanger is condensed, the material in the second heat exchanger is emptied through the second emptying end of the emptying component, and then the air source component continuously inputs ambient air at room temperature to the second air inlet pipe, so that the ambient air at room temperature continues to flow through the second heat exchanger and is discharged by the exhaust component, and the material solution produced by melting in the second heat exchanger is discharged from the second emptying end of the emptying component, so that the wall of the inner wall of the heat exchanger can be effectively removed, and at the same time, the energy consumption of the heat exchanger when removing the wall is reduced, and the effect of removing the wall of the inner wall of the heat exchanger with low energy consumption is achieved.

[0073] 3. By controlling the refrigerant temperature output by the refrigeration component, not only the effect of continuous refrigeration cycle in a single crystal separator is achieved, but also the cooling curve and crystal nucleus amount of the crystal separator can be controlled, while also extending the wall forming period of a single heat exchanger, thereby extending the service life of a single heat exchanger.

[0074] The above-mentioned embodiments only express several implementation methods of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the disclosed patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present disclosure, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the disclosed patent shall be subject to the attached claims.

Claims

1. A freezing crystallization device (10), It is characterized in that include: A feed assembly (100), one end of the feed assembly (100) being in communication with a wastewater system; A crystal separator (200), wherein the other end of the feed assembly (100) is connected to the feed end of the crystal separator (200); A circulation component (300), wherein the circulation component (300) comprises a first circulation pump (310) and a second circulation pump (320), and the crystal separator (200) comprises a first pumping end and a second pumping end, wherein the feed end of the first circulation pump (310) is connected to the first pumping end of the crystal separator (200), and the feed end of the second circulation pump (320) is connected to the second pumping end of the crystal separator (200); The heat exchange component (400) comprises a first heat exchanger (410), a second heat exchanger (420), a first air inlet pipe (430) and a second air inlet pipe (440), the feed end of the first heat exchanger (410) is connected to the discharge end of the first circulation pump (310), the feed end of the second heat exchanger (420) is connected to the discharge end of the second circulation pump (320), the discharge end of the first heat exchanger (410) and the discharge end of the second heat exchanger (420) are both connected to the feed end of the crystallizer (200), the first heat exchanger (410) is provided with a first refrigerant inlet (412) and a first refrigerant inlet (430). The first heat exchanger (410) is provided with a second refrigerant inlet (422) and a second refrigerant outlet (424); the first refrigerant inlet (412), the first refrigerant outlet (414), the second refrigerant inlet (422) and the second refrigerant outlet (424) are all connected to the refrigeration system; one end of the first air inlet pipe (430) is connected to the feed end of the first heat exchanger (410); one end of the second air inlet pipe (440) is connected to the feed end of the second heat exchanger (420); the other end of the first air inlet pipe (430) and the other end of the second air inlet pipe (440) are both connected to the air source component; An exhaust component (500), wherein an exhaust end of the exhaust component (500) is respectively connected to a discharge end of the first heat exchanger (410) and a discharge end of the second heat exchanger (420); An emptying component (600), wherein a first emptying end of the emptying component (600) is connected to a feed end of the first heat exchanger (410), and a second emptying end of the emptying component (600) is connected to a feed end of the second heat exchanger (420).

2. The freezing crystallization device (10) according to claim 1, It is characterized in that The feed assembly (100) comprises a feed pump (110), a feed pipeline (120), a liquid receiving tank (130) and a flow guiding center cylinder (140); the liquid inlet end of the feed pump (110) is connected to the wastewater system; one end of the feed pipeline (120) is connected to the liquid outlet end of the feed pump (110); the other end of the feed pipeline (120), the discharge end of the first heat exchanger (410) and the discharge end of the second heat exchanger (420) are all connected to the liquid inlet end of the liquid receiving tank (130); one end of the flow guiding center cylinder (140) is connected to the liquid outlet end of the liquid receiving tank (130); and the other end of the flow guiding center cylinder (140) passes through the feed end of the crystallization separator (200) and extends into the crystallization chamber of the crystallization separator (200).

3. The freezing crystallization device (10) according to claim 2, It is characterized in that The exhaust assembly (500) comprises a first exhaust branch pipe (510), a second exhaust branch pipe (520), an exhaust main pipe (530) and an induced draft fan (540); one end of the first exhaust branch pipe (510) is connected to the discharge end of the first heat exchanger (410); one end of the second exhaust branch pipe (520) is connected to the discharge end of the second heat exchanger (420); and the exhaust main pipe (530) is respectively connected to the other end of the first exhaust branch pipe (510), the other end of the second exhaust branch pipe (520) and the induced draft fan (540).

4. The freezing crystallization device (10) according to claim 3, It is characterized in that The emptying component (600) includes a first emptying branch pipe (610), a second emptying branch pipe (620), an emptying pump (630) and an emptying collection tank (640), one end of the first emptying branch pipe (610) is connected to the feed end of the first heat exchanger (410), one end of the second emptying branch pipe (620) is connected to the feed end of the first heat exchanger (410), the other end of the first emptying branch pipe (610), the other end of the second emptying branch pipe (620) and the discharge end of the crystallization separator (200) are all connected to the liquid inlet end of the emptying pump (630), and the emptying collection tank (640) is connected to the liquid outlet end of the emptying pump (630).

5. The freezing crystallization device (10) according to claim 4, It is characterized in that The emptying assembly (600) further comprises an emptying reflux branch pipe (650), one end of which is connected to the liquid outlet end of the emptying pump (630), and the other end of which is connected to the liquid return end of the crystallization separator (200).

6. The freezing crystallization device (10) according to claim 5, It is characterized in that The freezing crystallization device (10) also includes a slurry extraction component (700), which includes a slurry extraction pump (710), a centrifuge (720) and a fine crystal separation tank (730). The liquid inlet end of the slurry extraction pump (710) is connected to the discharge end of the crystal separator (200), the liquid outlet end of the slurry extraction pump (710) is connected to the liquid inlet end of the centrifuge (720), and the liquid outlet end of the centrifuge (720) is connected to the liquid inlet end of the fine crystal separation tank (730).

7. The freezing crystallization device (10) according to claim 6, It is characterized in that The bottom of the fine crystal separation tank (730) is formed with an inclined surface, and the fine crystal separation tank (730) is provided with a fine crystal separation plate (7310), and one end of the fine crystal separation plate (7310) is arranged on the inclined surface.

8. The freezing crystallization device (10) according to claim 7, It is characterized in that The slurry extraction pump (710) also includes a fine crystal mother liquor reflux pump (740) and a mother liquor pump, the liquid inlet end of the fine crystal mother liquor reflux pump (740) is connected to the first liquid discharge end of the fine crystal separation tank (730), the liquid outlet end of the fine crystal mother liquor reflux pump (740) is connected to the liquid inlet end of the feed pump (110), the liquid inlet end of the mother liquor pump is connected to the second liquid discharge end of the fine crystal separation tank (730), and the liquid outlet end of the mother liquor pump is connected to the mother liquor collection device.

9. The freezing crystallization device (10) according to claim 8, It is characterized in that The freezing crystallization device (10) further includes an overflow pipe (800), one end of which is connected to the overflow port of the crystallization separator (200), and the other end of which is connected to the liquid inlet end of the fine crystal separation tank (730).

10. A freezing crystallization system, It is characterized in that It comprises the freezing crystallization device (10) according to any one of claims 1 to 9.

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