Wastewater evaporative crystallization equipment

Abstract

The utility model relates to the field of wastewater treatment, and discloses wastewater evaporative crystallization equipment which comprises a produced water circulating device, a crystallization circulating device, a separation device and a compression device, and the produced water circulating device comprises a first-stage circulating pump, a first-stage heat exchanger and a first-stage separator which are sequentially connected along the flow direction of wastewater; the liquid outlet end of the first-stage separator is connected with the liquid inlet end of the first-stage circulating pump; the crystallization circulating device comprises a second-stage circulating pump, a second-stage heat exchanger and a second-stage separator which are sequentially connected in the flowing direction of wastewater, the liquid outlet end of the second-stage separator is connected with the liquid inlet end of the second-stage circulating pump, the liquid inlet end of the second-stage separator is further connected with the liquid outlet end of the first-stage circulating pump, and a liquid level adjusting valve is arranged between the produced water circulating device and the crystallization circulating device; the separation device is connected with the crystallization circulation device; and the compression device is connected with the primary separator, the secondary separator, the primary heat exchanger and the secondary heat exchanger. The evaporative crystallization equipment provided by the utility model can solve the problems of how to improve the wastewater treatment efficiency and reduce the evaporation cost.

Description

Technical Field

[0001] The utility model relates to the field of wastewater treatment, in particular to wastewater evaporation and crystallization equipment. Background Art

[0002] MVR evaporator is a high-efficiency and energy-saving evaporation crystallization equipment. It does not require any extra steam heat source, but only uses the energy of the secondary steam generated by itself as the power for treating wastewater. Therefore, it is widely used in chemical, pharmaceutical, sewage treatment and other industries.

[0003] In the prior art, an MVR evaporation crystallization device includes a feed pump, a preheater, a forced circulation heat exchanger, a crystallizer, a forced circulation pump, a compressor, a thickener, a mother liquid tank and a centrifuge connected to each other. When the MVR evaporation crystallization device is used, the high-concentration wastewater is first input into the preheater through the feed pump for preheating. After preheating, the forced circulation pump is sequentially circulated into the forced circulation heat exchanger and the crystallizer. The crystallizer evaporates and concentrates the wastewater to produce mother liquid and secondary steam, wherein the secondary steam is input into the forced circulation heat exchanger after being heated by the compressor as a heat source for heating the high-concentration wastewater by the forced circulation heat exchanger, and the mother liquid is pumped back to the forced circulation heat exchanger by the forced circulation pump for recirculation evaporation until the mother liquid concentration reaches the set value, and the mother liquid is input into the thickener for preliminary separation, and the separated mother liquid is stored in the mother liquid tank. The secondary steam in the forced circulation heat exchanger exchanges heat with the wastewater to produce condensed water, which is input into the preheater as a heat source for preheating the wastewater by the preheater to preheat the concentrated water.

[0004] Among them, the MVR evaporation crystallization device needs to use a large-volume separator to accommodate and evaporate and concentrate a large amount of high-concentration wastewater to improve wastewater treatment efficiency. However, the price of a large-volume separator is much higher than that of a small-volume separator, resulting in a high evaporation cost of the evaporation crystallization device. Utility Model Content

[0005] 1. Technical issues to be resolved

[0006] The utility model provides a wastewater evaporation crystallization device, which can at least solve the technical problem of: how to improve the wastewater treatment efficiency and reduce the evaporation cost.

[0007] (II) Technical solution

[0008] In order to solve the above technical problems, the utility model provides the following technical solutions: a wastewater evaporation and crystallization device, comprising:

[0009] The water production circulation device comprises a primary circulation pump, a primary heat exchanger and a primary separator which are sequentially connected along the flow direction of the wastewater, and the liquid outlet of the primary separator is connected to the liquid inlet of the primary circulation pump;

[0010] The crystallization circulation device comprises a secondary circulation pump, a secondary heat exchanger and a secondary separator which are sequentially connected along the flow direction of the wastewater, the liquid outlet of the secondary separator is connected to the liquid inlet of the secondary circulation pump, the liquid inlet of the secondary separator is also connected to the liquid outlet of the primary circulation pump, a liquid level regulating valve is arranged between the water production circulation device and the crystallization circulation device, and the liquid level regulating valve is used to control the flow rate of the feed liquid inputted from the water production circulation device to the crystallization circulation device;

[0011] A separation device, connected to the crystallization circulation device, for inputting and separating the feed liquid output from the secondary separator to form crystalline salt;

[0012] The compression device is connected with the primary separator, the secondary separator, the primary heat exchanger and the secondary heat exchanger. The compression device is used for compressing the secondary steam generated by the primary separator and the secondary separator, and inputting the secondary steam into the primary heat exchanger and the secondary heat exchanger.

[0013] It is further configured that the wastewater evaporation and crystallization equipment also includes a vacuum pump, the vacuum pump is connected to the secondary heat exchanger through a gas pipeline, and the vacuum pump is also connected to the gas deodorization system.

[0014] Further, the wastewater evaporation and crystallization device also includes:

[0015] A preheating device, the liquid outlet of the preheating device is connected between the primary separator and the primary circulation pump, and is used to input and preheat the wastewater, and transport the preheated wastewater to the primary separator;

[0016] The condensing device is connected to the primary heat exchanger, the secondary heat exchanger and the preheating device respectively. The condensing device is used to send the condensed water and non-condensable steam formed in the primary heat exchanger and the secondary heat exchanger to the preheating device together.

[0017] It is further configured that the aforementioned preheating device includes a condensate heat exchanger and a non-condensate steam heat exchanger, the liquid outlet end of the condensate heat exchanger is connected to the liquid inlet end of the non-condensate steam heat exchanger, and the liquid outlet end of the non-condensate steam heat exchanger is connected between the primary separator and the primary circulation pump.

[0018] It is further configured that the aforementioned condensing device includes a condensing water pump and a condenser, the water inlet end of the condensing water pump is respectively connected to the water outlet end of the first-stage heat exchanger, the water outlet end of the second-stage heat exchanger, the water outlet end of the non-condensing heat exchanger and the condenser, and the water outlet end of the condensing water pump is connected to the water inlet end of the condensing water heat exchanger.

[0019] It is further arranged that the aforementioned compression device is also connected to the air inlet end of the condenser.

[0020] It is further provided that the aforementioned separation device comprises a centrifuge, a density meter and a control three-way valve, the density meter is installed on the pipeline of the crystallization circulation device, and the density meter is used to detect the density of the mother liquor circulating in the crystallization circulation device; the liquid inlet end of the centrifuge is connected between the secondary circulation pump and the secondary heat exchanger through the control three-way valve, and the control three-way valve is used to control the connection or cutoff between the crystallization circulation device and the liquid inlet end of the centrifuge;

[0021] When the density detected by the densitometer reaches a preset range, the three-way valve is controlled to connect the crystallization circulation device with the liquid inlet end of the centrifuge.

[0022] It is further arranged that both the first-stage separator and the second-stage separator are provided with demisters.

[0023] (III) Beneficial effects

[0024] Compared with the prior art, the wastewater evaporation and crystallization equipment provided by the utility model has the following features:

[0025] Beneficial effects:

[0026] 1. When the evaporation crystallization device provided by the utility model is used, the wastewater is first input into the water production circulation device for evaporation and concentration. The water production circulation device drives most of the wastewater through the primary heat exchanger and the primary separator in sequence through the primary circulation pump, and a small part of the wastewater flows into the crystallization circulation device continuously through the liquid level regulating valve. The primary separator flashes the wastewater to obtain mother liquor and secondary steam, wherein part of the mother liquor is driven by the primary circulation pump to continue to circulate in the water production circulation device, and part of the mother liquor flows into the crystallization circulation device through the liquid level regulating valve, and the cycle is continuous. At the same time, the feed liquid (including the mother liquor) is input into the crystallization circulation device for further evaporation and concentration. The evaporation and concentration cycle of the crystallization circulation device is the same as that of the above-mentioned water production circulation device, wherein the secondary steam obtained by flash evaporation of the primary separator and the secondary separator is compressed and heated by the compression device and then input into the primary heat exchanger and the secondary heat exchanger to heat and evaporate the feed liquid in the primary heat exchanger and the secondary heat exchanger; the cycle is continuous until the mother liquor in the crystallization circulation device reaches a preset density and then input into the separation device, and the separation device separates and discharges the salt mud in the mother liquor. In this way, the water production circulation device and the crystallization circulation device of the evaporation crystallization equipment are controlled by the liquid level regulating valve, and can dynamically and continuously feed liquid to continuously treat wastewater. It can be seen that the water production circulation device and the crystallization circulation device of the evaporation crystallization equipment can simultaneously circulate and evaporate the concentrated mother liquor, thereby effectively improving the wastewater treatment efficiency of the evaporation crystallization equipment.

[0027] 2. The evaporation and crystallization equipment can simultaneously circulate and evaporate the concentrated mother liquor through the water production circulation device and the crystallization circulation device, and can accommodate and treat a large amount of high-concentration wastewater. Therefore, the primary separator and the secondary separator of the evaporation and crystallization equipment can both use small-volume separators to achieve the effect of existing large-volume separators, and the cost of small-volume separators is lower, thereby reducing the evaporation cost of the evaporation and crystallization equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a connection diagram of the wastewater evaporation and crystallization equipment in the embodiment.

[0029] Figure Number:

[0030] 1. Preheating device; 11. Condensate heat exchanger; 12. Non-condensing steam heat exchanger;

[0031] 2. Water production circulation device; 21. Primary circulation pump; 22. Primary heat exchanger; 23. Primary separator; 24. Three-way valve;

[0032] 3. Crystallization circulation device; 31. Secondary circulation pump; 32. Secondary heat exchanger; 33. Secondary separator; 34. Liquid level regulating valve;

[0033] 4. Separation device; 41. Centrifuge; 42. Salt mud tank; 43. Mother liquid tank; 44. Density meter; 45. Control three-way valve;

[0034] 5. Compression device;

[0035] 6. Condensation device; 61. Condensate pump; 62. Condenser;

[0036] 7. Vacuum pump; 8. Feed tank; 9. Feed pump. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by conventional technicians in this field without creative work are within the scope of protection of the utility model.

[0038] The utility model provides a wastewater evaporation crystallization device, which is used to solve the problem of how to improve wastewater treatment efficiency and reduce evaporation cost.

[0039] See also Figure 1 As shown, Figure 1Schematic diagram of the connection of the wastewater evaporation and crystallization equipment in the embodiment, the wastewater evaporation and crystallization equipment includes a preheating device 1, a water production circulation device 2, a crystallization circulation device 3, a separation device 4, a compression device 5 and a condensation device 6.

[0040] The water production circulation device 2 includes a primary circulation pump 21, a primary heat exchanger 22 and a primary separator 23. The primary circulation pump 21, the primary heat exchanger 22 and the primary separator 23 are connected in sequence through a feed liquid pipeline along the flow direction of the wastewater, and the liquid outlet end of the primary separator 23 is connected to the liquid inlet end of the primary circulation pump 21, thereby forming a feed liquid concentration circulation loop.

[0041] The crystallization circulation device 3 includes a secondary circulation pump 31, a secondary heat exchanger 32 and a secondary separator 33. The secondary circulation pump 31, the secondary heat exchanger 32 and the secondary separator 33 are connected in sequence through the feed liquid pipeline along the flow direction of the wastewater, and the liquid outlet of the secondary separator 33 is connected to the liquid inlet of the secondary circulation pump 31, thereby forming a feed liquid concentration circulation loop. Among them, the primary separator 23 and the secondary separator 33 are both used to evaporate and concentrate the wastewater, and produce mother liquid and secondary steam. The secondary steam rises in the primary separator 23 and the secondary separator 33, thereby separating from the mother liquid. The liquid inlet of the secondary separator 33 is also connected to the liquid outlet of the primary circulation pump 21 through the feed liquid pipeline, thereby connecting the water production circulation device 2 and the crystallization circulation device 3. In this way, the mother liquid generated by the water production circulation device 2 is first input into the secondary separator 33 of the crystallization circulation device 3, and the secondary separator 33 performs gas-liquid separation, and then performs circulation evaporation and concentration.

[0042] A liquid level regulating valve 34 is installed between the water production circulation device 2 and the crystallization circulation device 3 . The liquid level regulating valve 34 is used to control the flow rate of the feed liquid from the water production circulation device 2 to the crystallization circulation device 3 .

[0043] The separation device 4 is connected to the crystallization circulation device 3 through a feed liquid pipeline. The separation device 4 is used to input and separate the feed liquid output from the secondary separator 33 (i.e., the mother liquid output from the crystallization circulation device 3) to form crystalline salt (also called "salt mud").

[0044] The compression device 5 is connected to the gas outlet end of the primary separator 23, the gas outlet end of the secondary separator 33, the gas channel of the primary heat exchanger 22, and the gas channel of the secondary heat exchanger 32 through a gas pipeline. The compression device 5 is used to compress the secondary steam generated by the primary separator 23 and the secondary separator 33 to increase the temperature of the secondary steam, and input the heated secondary steam into the primary heat exchanger 22 and the secondary heat exchanger 32 as a heat source for heating and evaporating wastewater in the primary heat exchanger 22 and the secondary heat exchanger 32, thereby recycling the heat source (secondary steam) and reducing energy consumption. While the secondary steam heats the wastewater in the primary heat exchanger 22 and the secondary heat exchanger 32, it will also be condensed by the wastewater in the primary heat exchanger 22 and the secondary heat exchanger 32 to form condensed water and non-condensable steam (i.e., gas that cannot be condensed into water).

[0045] The above-mentioned water production circulation device 2 and crystallization circulation device 3 have the same use process, but different main functions. Among them, the water production circulation device 2 is mainly used to concentrate the feed liquid and produce a large amount of condensed water. The water production circulation device 2 can continuously circulate and concentrate the wastewater through three devices: a primary circulation pump 21, a primary heat exchanger 22 and a primary separator 23, and produce a large amount of water, which greatly shortens the path of concentrated water production, thereby effectively improving the water production efficiency; and the water production rate of the concentrated mother liquor is greatly reduced. Therefore, the crystallization circulation device 3 further evaporates and concentrates the mother liquor produced by the water production circulation device 2, mainly to concentrate the mother liquor, crystallize the mother liquor, and precipitate salt mud.

[0046] When the evaporation crystallization equipment provided by the above technical solution is used, the wastewater is first input into the water production circulation device 2 for evaporation and concentration. The water production circulation device 2 drives most of the wastewater through the primary heat exchanger 22 and the primary separator 23 in sequence through the primary circulation pump 21, and a small part of the wastewater flows continuously into the crystallization circulation device 3 through the liquid level regulating valve 34. The primary separator 23 flashes the wastewater to obtain mother liquor and secondary steam, among which part of the mother liquor is driven by the primary circulation pump 21 to continue to circulate, and part of the mother liquor flows into the crystallization circulation device 3 through the liquid level regulating valve 34, and the cycle continues. At the same time, the feed liquid (including the mother liquor) is input into the crystallization circulation device 3 for further evaporation and concentration. The evaporation and concentration process of the crystallization circulation device 3 is the same as that of the above-mentioned water production circulation device 2, wherein the secondary steam obtained by flash evaporation in the primary separator 23 and the secondary separator 33 is compressed and heated by the compression device 5 and then input into the primary heat exchanger 22 and the secondary heat exchanger 32 to heat and evaporate the feed liquid in the primary heat exchanger 22 and the secondary heat exchanger 32. This cycle is continuously repeated until the mother liquor in the crystallization circulation device 3 reaches a preset density (or concentration, the concentration can be obtained by converting the density) and is then input into the separation device 4, and the separation device 4 separates and discharges the salt mud in the mother liquor. In this way, the water production circulation device 2 and the crystallization circulation device 3 of the evaporation crystallization equipment are controlled by the liquid level regulating valve 34, and can dynamically and continuously feed liquid to continuously treat wastewater. It can be seen that the water production circulation device 2 and the crystallization circulation device 3 of the evaporation crystallization equipment can simultaneously circulate and evaporate the concentrated mother liquor, thereby effectively improving the wastewater treatment efficiency of the evaporation crystallization equipment; the evaporation crystallization equipment can simultaneously circulate and evaporate the concentrated mother liquor through the water production circulation device 2 and the crystallization circulation device 3, so as to accommodate and treat a large amount of high-concentration wastewater. Therefore, the primary separator 23 and the secondary separator 33 of the evaporation crystallization equipment can use small-volume separators to achieve the effect of existing large-volume separators, and the cost of small-volume separators is lower, thereby reducing the evaporation cost of the evaporation crystallization equipment.

[0047] The above-mentioned primary heat exchanger 22 and secondary heat exchanger 32 can both use existing plate heat exchangers, the primary separator 23 and secondary separator 33 can both use existing evaporative separators, and the compression device 5 can use an existing steam compressor. In this way, the steam compressor can work to compress the secondary steam, thereby increasing the pressure and temperature of the secondary steam. After the pressure and temperature of the secondary steam reach the preset values, the secondary steam is input into the primary heat exchanger 22 and the secondary heat exchanger 32 to heat the wastewater.

[0048] The liquid level regulating valve 34 can be made by combining an existing liquid level sensor and an existing three-way regulating valve. The liquid level sensor is installed in the tank body of the secondary separator 33 to detect the liquid level of the secondary separator 33, and the three ends of the three-way regulating valve are respectively connected to the secondary separator 33, the primary circulation pump 21 and the primary heat exchanger 22. The three-way regulating valve can control the connection or cutoff of the primary circulation pump 21 and the secondary separator 33, and can also control the degree of connection between the primary circulation pump 21 and the secondary separator 33 to control the liquid flow rate of the water production circulation device 2 flowing into the secondary separator 33. In this way, the liquid level sensor and the three-way regulating valve can cooperate to limit the liquid level in the tank body of the secondary separator 33 to remain within a preset range. If the liquid level is lower than the preset range, the three-way regulating valve increases the flow rate of the water production circulation device 2 into the secondary separator 3 3, if the liquid level reaches the preset range, the three-way regulating valve reduces the liquid flow of the water production circulation device 2 into the secondary separator 33. If the liquid level exceeds the preset range, the three-way regulating valve cuts off the primary circulation pump 21 and the secondary separator 33, thereby avoiding too much or too little liquid in the tank body of the secondary separator 33, reducing the harm of cross-material caused by the boiling of the liquid. However, since the secondary separator 33 is always evaporating the liquid and lowering the liquid level in the tank body of the secondary separator 33, in actual use, the three-way regulating valve will not cut off the primary circulation pump 21 and the secondary separator 33, so that the water production circulation device 2 maintains a dynamic continuous liquid inlet state of flowing the liquid into the crystallization circulation device 3, thereby ensuring that the water production circulation device 2 and the crystallization circulation device 3 can circulate and evaporate the concentrated mother liquor at the same time, effectively improving the wastewater treatment efficiency.

[0049] The wastewater evaporation and crystallization equipment also includes a vacuum pump 7, which is connected to the gas channel of the secondary heat exchanger 32 through a gas pipeline, and is also connected to a gas deodorization system (not shown in the figure). In this way, the vacuum pump 7 is used to extract the non-condensable steam in the evaporation and crystallization equipment, provide negative pressure for the evaporation and crystallization equipment, reduce the boiling point of the wastewater, so that the wastewater evaporates and crystallizes, and the extracted non-condensable steam can be discharged into the gas deodorization system for deodorization treatment and then discharged outside the evaporation and crystallization equipment to avoid polluting the atmosphere.

[0050] The wastewater evaporation and crystallization equipment also includes a preheating device 1 and a condensing device 6. The liquid outlet of the preheating device 1 is connected between the liquid outlet of the primary separator 23 and the liquid inlet of the primary circulation pump 21. The preheating device 1 is used to input and preheat wastewater, and transport the wastewater to the primary separator 23 for evaporation and concentration. The condensing device 6 is respectively connected to the primary heat exchanger 22, the secondary heat exchanger 32 and the preheating device 1. The condensing device 6 is used to send the condensed water and non-condensable steam formed in the primary heat exchanger 22 and the secondary heat exchanger 32 into the preheating device 1 as a heat source for preheating wastewater by the preheating device 1. In this way, the evaporation and crystallization equipment first preheats the wastewater through the preheating device 1, and then sends it to the water production circulation device 2 for evaporation and concentration, which can further improve the treatment efficiency of wastewater evaporation and crystallization; the evaporation and crystallization equipment recycles the heat source generated during the working process through the condensing device 6 as the heat source of the preheating device 1, effectively saving energy consumption and reducing evaporation costs.

[0051] In one embodiment of the preheating device 1, the preheating device 1 includes a condensate heat exchanger 11 and a non-condensing steam heat exchanger 12, the liquid outlet end of the condensate heat exchanger 11 and the liquid inlet end of the non-condensing steam heat exchanger 12 are connected through a feed-liquid pipeline, the liquid outlet end of the non-condensing steam heat exchanger 12 is connected between the liquid outlet end of the primary separator 23 and the liquid inlet end of the primary circulation pump 21 through the feed-liquid pipeline, the water outlet end of the condensing device 6 is connected to the water inlet end of the condensate heat exchanger 11 through a condensate pipeline, and the gas outlet end of the condensing device 6 is connected to the gas inlet end of the non-condensing steam heat exchanger 12 through a gas pipeline. In this way, the condensed water heat exchanger 11 and the non-condensing steam heat exchanger 12 respectively use the condensed water and non-condensing steam provided by the condensing device 6 as heat sources for heat exchange. When the evaporation and crystallization equipment is in use, the pretreated wastewater is successively sent to the condensed water heat exchanger 11 and the non-condensing steam heat exchanger 12 for heat exchange, and then sent to the water production circulation device 2 for evaporation and concentration after being heated twice, thereby further improving the treatment efficiency of wastewater evaporation and crystallization.

[0052] A three-way valve 24 is installed at the connection between the above-mentioned preheating device 1 (non-condensing steam heat exchanger 12) and the primary separator 23 and the primary circulation pump 21. The three-way valve 24 can use a conventional three-way valve 24 or the above-mentioned liquid level regulating valve 34. If the liquid level regulating valve 34 is used, the liquid level sensor of the liquid level regulating valve 34 is installed in the tank of the primary separator 23 to detect the liquid level in the primary separator 23, and the three ends of the three-way regulating valve are respectively connected to the non-condensing steam heat exchanger 12, the primary separator 23 and the primary circulation pump 21. The three-way regulating valve can control the connection or cutoff of the non-condensing steam heat exchanger 12 and the primary circulation pump 21, and can also control the degree of connection between the non-condensing steam heat exchanger 12 and the primary circulation pump 21, so as to control the liquid from the preheating device 1 to flow into the water production circulation device 2. Flow rate, in this way, the liquid level sensor and the three-way regulating valve can cooperate to limit the liquid level in the tank of the first-stage separator 23 to remain in the preset range, avoiding too much or too little liquid in the tank of the first-stage separator 23, and further reducing the harm of cross-contamination caused by the boiling of the liquid. However, because the first-stage separator 23 is always evaporating the liquid, in actual use, the three-way regulating valve does not cut off the preheating device 1 and the first-stage separator 23, thereby ensuring that the water production circulation device 2 and the crystallization circulation device 3 can circulate and evaporate the concentrated mother liquor at the same time, effectively improving the wastewater treatment efficiency.

[0053] In one embodiment of the condensing device 6, the condensing device 6 includes a condensing water pump 61 and a condenser 62, the water inlet end of the condensing water pump 61 is connected to the water outlet end of the first-level heat exchanger 22, the water outlet end of the second-level heat exchanger 32, the water outlet end of the non-condensing steam heat exchanger 12 and the condenser 62 through a condensing water pipeline, and the water outlet end of the condensing water pump 61 is connected to the water inlet end of the condensing water heat exchanger 11 through a condensing water pipeline. In this way, when the evaporation crystallization equipment is first used, the primary heat exchanger 22 and the secondary heat exchanger 32 have not yet produced condensed water. At this time, the condensed water pump 61 sends the condensed water in the condenser 62 that has not been heat exchanged (the condensed water provided by the outside to the condenser 62) to the condensed water heat exchanger 11 as the initial heat source for the condensed water heat exchanger 11 to preheat the wastewater. The non-condensing steam heat exchanger 12 also uses the primary steam provided by the outside as the initial heat source. After the evaporation crystallization equipment has been used for a period of time, the condensed water pump 61 sends the condensed water formed by heat exchange in the primary heat exchanger 22, the secondary heat exchanger 32, the non-condensing steam heat exchanger 12 and the condensed water in the condenser 62 to the condensed water heat exchanger 11 as the heat source of the condensed water heat exchanger 11, replacing the heat source provided by the outside to the condenser 62. After preheating, the condensed water in the condensed water heat exchanger 11 can be discharged after post-treatment to meet the standards, or recycled; and the non-condensable steam formed in the first-level heat exchanger 22 and the second-level heat exchanger 32 can enter the non-condensing steam heat exchanger 12, as the heat source for the non-condensing steam heat exchanger 12 to preheat the waste water, replacing the primary steam provided from the outside. After the non-condensable steam is heat exchanged, part of the condensable gas carried therein is condensed into condensed water, and the remaining non-condensable steam can continue to enter the condenser 62, exchange heat with the circulating cooling water provided by the outside in the condenser 62, and further condense to obtain condensed water and remaining non-condensable steam, thereby further improving the water production rate. The final non-condensable gas is pumped out by the vacuum pump 7 for discharge or drawn into the gas deodorization system for further treatment and then discharged. It can be seen that the condensation device 6 can recycle condensed water and non-condensable steam through the condensation water pump 61 and the condenser 62, replacing the external heat source provided for the preheating device 1, eliminating the external heat source, effectively saving energy consumption, and reducing the evaporation cost. In the process of recycling the non-condensable steam, it can also fully condense the water carried in the non-condensable steam, effectively preventing water vapor from following the non-condensable gas into the vacuum pump 7, thereby ensuring the vacuum degree inside the evaporation crystallization equipment.

[0054] On the basis of the above embodiment, the compression device 5 is further connected to the air inlet end of the condenser 62 through a gas pipeline. In this way, when the preset negative pressure cannot be reached in the evaporation crystallization device, the compression device 5 can work with the condensation water pump 61 to suck part of the non-condensable steam in the primary heat exchanger 22 and the secondary heat exchanger 32 into the condenser 62, and exchange heat with the circulating cooling water in the condenser 62, so that the preset negative pressure is reached in the evaporation crystallization device, thereby ensuring that the evaporation pressure of the evaporation crystallization device can meet the design requirements.

[0055] In one embodiment of the separation device 4, the separation device 4 includes a centrifuge 41, a density meter 44 and a control three-way valve 45. The density meter 44 is installed on the pipeline of the crystallization circulation device 3. The density meter 44 is used to detect the density of the mother liquid circulating in the crystallization circulation device 3. The liquid inlet end of the centrifuge 41 is connected between the liquid outlet end of the secondary circulation pump 31 and the liquid inlet end of the secondary heat exchanger 32 through the feed liquid pipeline, and the control three-way valve 45 is installed at the connection. The control three-way valve 45 is used to control the connection or cutoff between the crystallization circulation device 3 and the liquid inlet end of the centrifuge 41. In the original state, the three-way valve 45 is controlled to control the crystallization circulation device 3 and the liquid inlet end of the centrifuge 41 to be cut off, so that the mother liquor is always circulated in the crystallization circulation device 3 for evaporation and concentration, until the density meter 44 detects that the density of the mother liquor in the crystallization circulation device 3 reaches a preset range, and the three-way valve 45 is controlled to control the crystallization circulation device 3 to be connected with the liquid inlet end of the centrifuge 41, so that the mother liquor in the crystallization circulation device 3 can be input into the centrifuge 41 for centrifugal separation to obtain salt mud and supernatant (i.e., mother liquor). It can be seen that the evaporation crystallization equipment can always detect the density of the mother liquor in the crystallization circulation device 3 through the density meter 44, can accurately control the concentration end point of the evaporation crystallization equipment, and effectively avoid the phenomenon of liquid crystallization blocking the crystallization circulation device 3; and the evaporation crystallization equipment can always keep the mother liquor in the crystallization circulation device 3 that has not reached the set density in a large flow circulation state by controlling the three-way valve 45, and cannot flow into the centrifuge 41, thereby further improving the wastewater treatment efficiency of the evaporation crystallization equipment.

[0056] The above-mentioned density meter 44 can use the existing mass flow (density) meter 44, and can be installed on any feed liquid pipeline in the crystallization circulation device 3, but it is preferably installed on the feed liquid pipeline between the liquid outlet end of the secondary separator 33 and the control three-way valve 45 at the liquid inlet end of the centrifuge 41, which can improve the detection accuracy of the density meter 44 on the mother liquid density input to the centrifuge 41. The above-mentioned control three-way valve 45 can use the existing electromagnetic three-way valve or regulating valve, and can automatically control the connection or cutoff of the crystallization circulation device 3 and the centrifuge 41 through existing controllers and other equipment.

[0057] On the basis of the above embodiment, a mother liquor pump (not shown in the figure) can be installed on the liquid pipeline between the liquid inlet end of the centrifuge 41 and the control three-way valve 45. The mother liquor pump can provide power to quickly transport the mother liquor to the centrifuge 41 for centrifugal separation, thereby further improving the wastewater treatment efficiency of the evaporation crystallization equipment.

[0058] The liquid outlet end of the above-mentioned centrifuge 41 can be connected between the liquid outlet end of the secondary separator 33 and the liquid inlet end of the secondary circulation pump 31 through a feed liquid pipeline, and can also be connected to a salt mud tank 42 and a mother liquid tank 43 through a feed liquid pipeline. The former can return the supernatant obtained by centrifugation to the crystallization circulation device 3 for continued evaporation and concentration, while the latter can directly discharge the supernatant obtained by centrifugation into the mother liquid tank 43, and input the separated salt mud into the salt mud tank 42.

[0059] In one embodiment of the primary separator 23 and the secondary separator 33, a demister (not shown) is installed in both the primary separator 23 and the secondary separator 33. In this embodiment, the demister can use an existing wire mesh demister. In this way, the steam in the primary separator 23 and the secondary separator 33 (the steam is mainly the secondary steam generated by the evaporation of the feed liquid in the primary separator 23 and the secondary separator 33) rises upward, and the steam will pass through the demister during the rising process, so that most of the liquid particles carried in the steam (i.e., the mother liquid liquid particles in the primary separator 23 and the secondary separator 33) can be automatically intercepted, achieving the effect of gas-liquid separation, greatly reducing the impact of the liquid particles carried in the steam on the compressor impeller, thereby reducing the damage to the compressor impeller, while reducing the cross-material hazard caused by the boiling of the feed liquid in the primary separator 23 and the secondary separator 33, and improving the outlet water quality of the condensed water.

[0060] The wastewater evaporation and crystallization equipment also includes a feed tank 8 and a feed pump 9. The liquid outlet end of the feed tank 8 is connected to the liquid inlet end of the feed pump 9 through a feed-liquid pipeline, and the liquid outlet end of the feed pump 9 is connected to the liquid inlet end of the preheating device 1 through a feed-liquid pipeline. In this way, the wastewater is sent to the feed tank 8 of the evaporation and crystallization equipment after front-end process treatment. When the evaporation and crystallization equipment is in use, the feed pump 9 pumps the wastewater in the feed tank 8 into the preheating device 1 for preheating.

[0061] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wastewater evaporation and crystallization device, characterized in that: include: The water production circulation device comprises a primary circulation pump, a primary heat exchanger and a primary separator which are sequentially connected along the flow direction of the wastewater, wherein the liquid outlet of the primary separator is connected to the liquid inlet of the primary circulation pump; A crystallization circulation device, comprising a secondary circulation pump, a secondary heat exchanger and a secondary separator connected in sequence along the flow direction of the wastewater, wherein the liquid outlet of the secondary separator is connected to the liquid inlet of the secondary circulation pump, and the liquid inlet of the secondary separator is also connected to the liquid outlet of the primary circulation pump, and a liquid level regulating valve is provided between the water production circulation device and the crystallization circulation device, and the liquid level regulating valve is used to control the flow rate of the feed liquid input from the water production circulation device to the crystallization circulation device; A separation device, connected to the crystallization circulation device, used to input and separate the feed liquid output from the secondary separator to form crystalline salt; A compression device is connected to the primary separator, the secondary separator, the primary heat exchanger and the secondary heat exchanger. The compression device is used to compress the secondary steam generated by the primary separator and the secondary separator, and input the secondary steam into the primary heat exchanger and the secondary heat exchanger.

2. A wastewater evaporation and crystallization equipment according to claim 1, characterized in that: It also includes a vacuum pump, which is connected to the secondary heat exchanger through a gas pipeline, and is also connected to a gas deodorization system.

3. A wastewater evaporation and crystallization equipment according to claim 1, characterized in that: Also includes: A preheating device, wherein the liquid outlet end of the preheating device is connected between the primary separator and the primary circulation pump, and is used to input and preheat wastewater, and transport the preheated wastewater to the primary separator; A condensing device, wherein the condensing device is respectively connected to the primary heat exchanger, the secondary heat exchanger and the preheating device, and the condensing device is used to send the condensed water and non-condensable steam formed in the primary heat exchanger and the secondary heat exchanger into the preheating device together.

4. A wastewater evaporation and crystallization equipment according to claim 3, characterized in that: The preheating device includes a condensate heat exchanger and a non-condensate heat exchanger. The liquid outlet of the condensate heat exchanger is connected to the liquid inlet of the non-condensate heat exchanger. The liquid outlet of the non-condensate heat exchanger is connected between the primary separator and the primary circulation pump.

5. A wastewater evaporation and crystallization equipment according to claim 4, characterized in that: The condensing device includes a condensing water pump and a condenser. The water inlet end of the condensing water pump is respectively connected to the water outlet end of the primary heat exchanger, the water outlet end of the secondary heat exchanger, the water outlet end of the non-condensing heat exchanger and the condenser, and the water outlet end of the condensing water pump is connected to the water inlet end of the condensing water heat exchanger.

6. A wastewater evaporation and crystallization equipment according to claim 5, characterized in that: The compression device is also connected to the air inlet end of the condenser.

7. A wastewater evaporation and crystallization equipment according to claim 1, characterized in that: The separation device comprises a centrifuge, a density meter and a control three-way valve, wherein the density meter is installed on the pipeline of the crystallization circulation device, and the density meter is used to detect the density of the mother liquor circulating in the crystallization circulation device; the liquid inlet end of the centrifuge is connected between the secondary circulation pump and the secondary heat exchanger through the control three-way valve, and the control three-way valve is used to control the connection or cutoff between the crystallization circulation device and the liquid inlet end of the centrifuge; When the density detected by the densitometer reaches a preset range, the control three-way valve connects the crystallization circulation device with the liquid inlet end of the centrifuge.

8. A wastewater evaporation and crystallization equipment according to claim 1, characterized in that: Demisters are provided in both the primary separator and the secondary separator.

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