Waste liquid concentration device

Abstract

The utility model relates to the technical field of industrial wastewater treatment, in particular to a waste liquid concentration device. A preheating device, a degassing device and an MVR evaporation device are arranged. The waste liquid input end of the preheating device is used for being communicated with an external waste liquid conveying pipeline. The waste liquid input end of the degassing device is communicated with the waste liquid output end of the preheating device, and the gas output end of the degassing device is communicated with the gas input end of the preheating device or used for being communicated with the outside. The waste liquid input end of the MVR evaporation device is communicated with the waste liquid output end of the degassing device, and the concentrated waste liquid output end of the MVR evaporation device is connected with an external evaporation crystallization device. The waste liquid is heated to the preset temperature through the preheating device, and the non-condensable gas in the waste liquid is discharged through the degassing device, so that the content of the non-condensable gas in the steam formed after the waste liquid enters the MVR evaporation device is controlled, the heat exchange efficiency of the MVR evaporation device is higher, and the technical problem that the heat exchange efficiency of the MVR evaporation device in the prior art is lower is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of industrial wastewater treatment, in particular to a waste liquid concentration device. Background Art

[0002] The domestic polysilicon industry mostly adopts the modified Siemens method, and only performs leaching operations on low-boiling chlorosilanes, hydrogen chloride, system start-up and shutdown emissions, and residual liquids from maintenance and other production processes. The tail gas mainly contains a large amount of hydrogen chloride, chlorosilane, hydrogen, and nitrogen. Since chlorosilane is easily hydrolyzed, alkaline solutions such as dilute NaOH solution and lime milk are often used for washing. Since lime milk is relatively cheap, a large amount of high-salt waste liquid is generated after tail gas leaching, which changes with the amount of process waste gas emissions. The TDS of the salty waste liquid ranges from 30,000 to 60,000 mg / L, and the main components of the salt waste liquid are calcium chloride and sodium chloride. Due to the large amount of waste liquid, in order to reduce the energy consumption of waste liquid treatment, the prior art generally adopts the method of concentrating the waste liquid through an MVR evaporation device and then performing crystallization operation through an evaporation crystallization device. However, since the waste liquid contains a certain amount of organic matter and carbon dioxide, it will volatilize and mix with steam during the concentration process of the MVR evaporation device and enter the shell side of the heater together, and exchange heat with the waste liquid in the tube side. The shell side steam is condensed into exhaust steam condensate, while the organic gas and carbon dioxide are non-condensable gases, which gradually accumulate in the shell side of the heater, so that the heat exchange tube wall is surrounded by a layer of non-condensable gas, which prevents the steam from contacting the wall surface, resulting in a large thermal conductivity, large thermal resistance, and greatly reduced heat transfer coefficient. Practice has proved that 1% non-condensable gas in steam will cause the steam condensation heat transfer coefficient to decrease by about 60%, which will seriously reduce the heat exchange efficiency of the MVR evaporation device. Utility Model Content

[0003] The utility model provides a waste liquid concentrating device, which solves the technical problem of low heat exchange efficiency of an MVR evaporating device in the prior art.

[0004] In order to solve the above technical problems, the technical solution adopted in this embodiment is as follows:

[0005] In some embodiments, the utility model provides a waste liquid concentration device, comprising:

[0006] A preheating device, the waste liquid input end of which is used to communicate with an out-of-bounds waste liquid conveying pipeline;

[0007] A degassing device, whose waste liquid input end is connected to the waste liquid output end of the preheating device; whose gas output end is connected to the gas input end of the preheating device, or is used to be connected to the outside;

[0008] The waste liquid input end of the MVR evaporation device is connected with the waste liquid output end of the degassing device; and the concentrated waste liquid output end is used to connect with the off-site evaporation crystallization device.

[0009] In some embodiments, the preheating device comprises:

[0010] The exhaust steam condensate preheater, whose waste liquid input end is the waste liquid input end of the preheating device; and whose shell side condensate input end is connected to the condensate output end of the MVR evaporation device;

[0011] An exhaust steam preheater, wherein the waste liquid input end thereof is connected to the waste liquid output end of the exhaust steam condensate preheater; the steam input end thereof is connected to the gas output end of the degassing device; and the condensate output end thereof is connected to the shell-side condensate input end of the exhaust steam condensate preheater;

[0012] The waste liquid input end of the steam preheater is connected with the waste liquid output end of the exhaust steam preheater; the waste liquid output end is the waste liquid output end of the preheating device; and the steam input end is used to be connected with the external steam transmission pipeline.

[0013] In some embodiments, the degassing device comprises:

[0014] A degassing tower, wherein the upper part of the internal cavity thereof is provided with a spray pipe, the input end of the spray pipe is the waste liquid input end of the degassing device; the gas output end thereof is the gas output end of the degassing device, and is connected to the steam input end of the exhaust steam preheater;

[0015] The evaporation feed pump has a waste liquid input end connected to the waste liquid output end of the degassing tower; it has a first waste liquid output end and a second waste liquid output end, the first waste liquid output end is connected to the spray pipe; the second waste liquid output end is the waste liquid output end of the degassing device.

[0016] In some embodiments, a water tank is disposed at the lower portion of the degassing tower, and a pH value detection device is installed in the water tank.

[0017] In some embodiments, the MVR evaporation device comprises:

[0018] The MVR separator has a first waste liquid input end and a second waste liquid input end; the first waste liquid input end is the waste liquid input end of the MVR evaporation device, and is connected to the second waste liquid output end of the evaporation feed pump; and the concentrated waste liquid output end is used to connect to an off-site evaporation crystallization device;

[0019] An MVR compressor, whose steam input end is in communication with the steam output end of the MVR separator;

[0020] The MVR heater has a shell-side steam input end connected to the steam output end of the MVR compressor; a shell-side condensate output end connected to the shell-side condensate input end of the exhaust steam condensate preheater; a tube-side waste liquid input end connected to the waste liquid output end of the MVR separator; and a tube-side waste liquid output end connected to the second waste liquid input end of the MVR separator.

[0021] In some embodiments, the MVR evaporation device further comprises:

[0022] An axial flow pump is arranged between the MVR separator and the MVR heater, wherein the waste liquid input end of the axial flow pump is connected with the waste liquid output end of the MVR separator, and the waste liquid output end of the axial flow pump is connected with the pipe-side waste liquid input end of the MVR heater.

[0023] In some embodiments, the MVR separator is configured with at least one of a spherical baffle, a labyrinth demister, and a wire mesh demister.

[0024] In some embodiments, the MVR evaporation device includes a plurality of the MVR compressors, and the plurality of the MVR compressors are connected in series.

[0025] In some embodiments, the MVR evaporation device further comprises:

[0026] The gas-liquid separation tank is arranged between the MVR separator and the MVR compressor, and its steam input end is connected with the steam output end of the MVR separator; its steam output end is connected with the steam input end of the MVR compressor; and its liquid output end is connected with the shell-side condensate input end of the exhaust steam condensate preheater.

[0027] In some embodiments, the waste liquid concentration device further comprises:

[0028] The exhaust steam condensate tank has an input end connected to the shell-side condensate output end of the MVR heater, the liquid output end of the gas-liquid separation tank and the condensate output end of the exhaust steam preheater; and an output end connected to the shell-side condensate input end of the exhaust steam condensate preheater.

[0029] Beneficial Effects

[0030] The utility model heats the waste liquid to a preset temperature through a preheating device, and then discharges the non-condensable gas in the waste liquid through a degassing device. Therefore, the non-condensable gas content in the steam formed after the waste liquid enters the MVR evaporation device is controlled, so that the heat exchange efficiency of the MVR evaporation device is higher, and the technical problem of low heat exchange efficiency of the MVR evaporation device in the prior art is solved.

[0031] Additional aspects and advantages of the embodiments of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be understood through the practice of the embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] The methods, systems and / or programs in the accompanying drawings will be further described according to exemplary embodiments. These exemplary embodiments will be described in detail with reference to the drawings. These exemplary embodiments are non-limiting exemplary embodiments, wherein example numbers represent similar mechanisms in the various views of the accompanying drawings.

[0034] Figure 1 It is a block diagram of a waste liquid concentrating device provided in one embodiment of the utility model.

[0035] Figure 2 It is a structural diagram of a waste liquid concentrating device provided in one embodiment of the utility model.

[0036] Description of reference numerals:

[0037] 100-preheating device; 110-exhaust steam condensate preheater; 120-exhaust steam preheater; 130-steam preheater;

[0038] 200-degassing device; 210-degassing tower; 220-evaporation feed pump;

[0039] 300-MVR evaporation device; 310-MVR separator; 311-axial flow pump; 312-gas-liquid separation tank; 320-MVR compressor; 330-MVR heater;

[0040] 400- Exhaust steam condensate tank. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the embodiment of the utility model clearer, the technical scheme in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, rather than all the embodiments. The components of the embodiment of the utility model generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiment of the utility model provided in the drawings is not intended to limit the scope of the utility model for protection, but merely represents the selected embodiment of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the utility model.

[0042] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0043] In the description of the present invention, it should be noted that the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0044] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] See also Figure 1In some embodiments, the present application provides a waste liquid concentration device, including a preheating device 100, a degassing device 200 and an MVR evaporation device 300. Among them, the waste liquid input end of the preheating device 100 is used to communicate with the waste liquid conveying pipeline outside the boundary. The waste liquid input end of the degassing device 200 is connected to the waste liquid output end of the preheating device 100, and its gas output end is connected to the gas input end of the preheating device 100, or is used to communicate with the outside. The waste liquid input end of the MVR evaporation device 300 is connected to the waste liquid output end of the degassing device 200, and its concentrated waste liquid output end is used to connect to the evaporation crystallization device outside the boundary. Taking calcium chloride waste liquid as an example, the waste liquid enters through the waste liquid input end of the preheating device 100 after emulsification and oil removal, is heated to 95°C in the preheating device 100, and then is discharged from the waste liquid output end of the preheating device 100 and enters from the waste liquid input end of the degassing device 200 for degassing treatment. In the degassing device 200, since the waste liquid has reached 95°C, the organic gas and non-condensable gas such as carbon dioxide gas in the waste liquid will volatilize and separate from the waste liquid, and mix with the steam evaporated from the waste liquid to form a mixed gas and be discharged from the gas output end of the degassing device 200. When the gas output end is directly connected to the outside, the mixed gas is directly discharged to the air. When the gas output end is connected to the gas input end of the preheating device 100, the mixed gas can be used to heat the subsequent waste liquid in the preheating device 100. After heating, the steam in the mixed gas condenses into water and is discharged from the preheating device 100, and the non-condensable gas in the mixed gas can be discharged to the air. After degassing, the waste liquid in the degassing device 200 is discharged from its waste liquid output end and enters from the waste liquid input end of the MVR evaporation device 300 for evaporation and separation operations. After evaporation, the waste liquid forms concentrated waste liquid and is discharged from the concentrated waste liquid output end of the MVR evaporation device 300, and then enters the evaporation crystallization device for subsequent operations.

[0046] The utility model heats the waste liquid to a preset temperature through the preheating device 100, and then discharges the non-condensable gas in the waste liquid through the degassing device 200. Therefore, the non-condensable gas content in the steam formed after the waste liquid enters the MVR evaporation device 300 is effectively controlled, so that the heat exchange efficiency of the MVR evaporation device 300 is higher, which solves the technical problem of low heat exchange efficiency of the MVR evaporation device in the prior art.

[0047] See also Figure 2In some embodiments, the preheating device 100 includes a waste steam condensate preheater 110, a waste steam preheater 120, and a steam preheater 130. The waste liquid input end of the waste steam condensate preheater 110 is the waste liquid input end of the preheating device 100, and its shell side condensate input end is connected to the condensate output end of the MVR evaporation device 300, and is used to use the condensate output from the MVR evaporation device 300 to perform the first stage preheating of the waste liquid. The waste liquid input end of the waste steam preheater 120 is connected to the waste liquid output end of the waste steam condensate preheater 110, and its steam input end is connected to the gas output end of the degassing device 200, and is used to use the gas discharged from the degassing device 200 to perform the second stage preheating of the waste liquid. The gas discharged from the degassing device 200 is partially cooled to condensed water after heat exchange, and part of the non-condensable gas is discharged to the air after heat exchange. The condensate output end of the exhaust steam preheater 120 is connected to the shell-side condensate input end of the exhaust steam condensate preheater 110, and is used to transport the condensate in the exhaust steam preheater 120 to the exhaust steam condensate preheater 110 to perform the first stage preheating of the waste liquid. The waste liquid input end of the steam preheater 130 is connected to the waste liquid output end of the exhaust steam preheater 120. The waste liquid output end of the steam preheater 130 is the waste liquid output end of the preheating device 100. The steam input end of the steam preheater 130 is used to communicate with the external raw steam transmission pipeline, and is used to use the raw steam to perform the third stage preheating of the waste liquid.

[0048] During use, the waste liquid enters through the waste liquid input end of the exhaust steam condensate preheater 110 after emulsification and oil removal, reaches its waste liquid output end through the tube side, and exchanges heat with the shell side condensate during the process to complete the first stage of preheating. The waste liquid enters through the waste liquid input end of the exhaust steam preheater 120, reaches its waste liquid output end through the tube side, and exchanges heat with the shell side gas during the process to complete the second stage of preheating. The waste liquid enters through the waste liquid input end of the steam preheater 130, reaches its waste liquid output end through the tube side, and exchanges heat with the raw steam in the shell side during the process to complete the third stage of preheating. The temperature of the waste liquid after three-stage preheating can reach above 90°C, and preferably, the temperature of the waste liquid is heated to 95°C.

[0049] Furthermore, when assembling the exhaust steam condensate preheater 110, since the waste liquid is prone to scaling and clogging, a horizontal shell-and-tube heat exchanger can be used, which is installed with an inclination angle during assembly and is installed on the floor for easy disassembly and cleaning. The exhaust steam preheater 120 uses a horizontal shell-and-tube heat exchanger assembled above the exhaust steam condensate preheater 110, saving space, and is installed with an inclination angle during installation, which is installed on the floor for easy disassembly and cleaning. The steam preheater 130 uses a horizontal shell-and-tube heat exchanger assembled above the exhaust steam preheater 120, saving space, and is installed with an inclination angle during installation, which is installed on the floor for easy disassembly and cleaning.

[0050] See also Figure 2In some embodiments, the degassing device 200 includes a degassing tower 210 and an evaporation feed pump 220. A spray pipe is disposed at the upper portion of the internal cavity of the degassing tower 210, and the input end of the spray pipe is the waste liquid input end of the degassing device 200. The gas output end of the degassing tower 210 is the gas output end of the degassing device 200, which is connected to the steam input end of the exhaust steam preheater 120. The waste liquid input end of the evaporation feed pump 220 is connected to the waste liquid output end of the degassing tower 210. The evaporation feed pump 220 has a first waste liquid output end and a second waste liquid output end, the first waste liquid output end is connected to the spray pipe, and the second waste liquid output end is the waste liquid output end of the degassing device 200, which is connected to the waste liquid input end of the MVR evaporation device 300.

[0051] When in use, the preheated waste liquid enters the spray pipe from the input end of the spray pipe and then sprays out from the nozzle, flows evenly from the upper part of the cavity of the degassing tower 210 to the bottom of the tower, releases the organic gas and carbon dioxide gas dissolved in the waste liquid, and the mixed gas composed of organic gas, carbon dioxide gas and water vapor evaporated from the waste liquid is discharged from the gas output end and enters the steam input end of the exhaust gas preheater, which is used for the second stage preheating of the waste liquid in the subsequent exhaust gas preheater. The material contact high temperature part of the cavity adopts TA2 conforming to Q345R material, and the other parts are Q345 anti-corrosion material. The waste liquid flowing to the bottom of the tower is discharged from the waste liquid output end, enters the waste liquid input end of the evaporation feed pump 220, and then a part enters the spray pipe again from the first waste liquid output end of the evaporation feed pump 220 to spray, further discharges the organic gas and carbon dioxide gas therein, and the other part is discharged from the second waste liquid output end of the evaporation feed pump 220 and enters the MVR evaporation device 300.

[0052] Furthermore, a water tank is disposed at the lower portion of the degassing tower 210, which can serve as a buffer tank before the waste liquid enters the evaporation feed pump 220, and can be used for acid adjustment of the waste liquid. A pH value detection device is installed in the water tank. Preferably, the pH value detection device can adopt an online pH meter, which can remotely read the pH value of the waste liquid in the water tank in real time. Preferably, the waste liquid is acidified to pH 5 and then enters the spray pipe or MVR evaporation device 300 through the evaporation feed pump 220.

[0053] See also Figure 2In some embodiments, the MVR evaporation device 300 includes an MVR separator 310, an MVR compressor 320, and an MVR heater 330. The MVR separator 310 has a first waste liquid input end and a second waste liquid input end. The first waste liquid input end is the waste liquid input end of the MVR evaporation device 300, which is connected to the second waste liquid output end of the evaporation feed pump 220, and its concentrated waste liquid output end is used to connect to the off-site evaporation crystallization device. The steam input end of the MVR compressor 320 is connected to the steam output end of the MVR separator 310. The shell-side steam input end of the MVR heater 330 is connected to the steam output end of the MVR compressor 320, the shell-side condensate output end is connected to the shell-side condensate input end of the exhaust steam condensate preheater 110, the tube-side waste liquid input end is connected to the waste liquid output end of the MVR separator 310, and the tube-side waste liquid output end is connected to the second waste liquid input end of the MVR separator 310.

[0054] When in use, the degassed waste liquid enters from the first waste liquid input end of the MVR separator 310, and after flash evaporation to generate steam, the evaporated and separated steam is discharged through the steam output end of the MVR separator 310, and enters the steam input end of the MVR compressor 320. The steam is compressed and works in the MVR compressor 320, and the steam with a higher relative temperature and relative pressure after increasing the temperature, pressure and enthalpy is discharged through the steam output end of the MVR compressor 320, and enters the shell-side steam input end of the MVR heater 330. The condensed water is discharged through the condensed water output end of the MVR heater 330, and enters through the shell-side condensed water input end of the exhaust steam condensate preheater 110, and is used for the first-stage preheating of the subsequent waste liquid. The tube-side waste liquid input and output of the MVR heater 330 are respectively connected to the waste liquid output and the second waste liquid input of the MVR separator 310, so that the waste liquid forms a loop in the tube-side of the MVR heater 330 and the MVR separator 310, and the waste liquid continuously circulates in the tube-side of the MVR heater 330, and then enters the MVR separator 310 for evaporation and separation after heat exchange with the steam in the shell side, and continuously concentrates until the waste liquid concentration reaches the preset standard, and finally the concentrated waste liquid is discharged from the concentrated waste liquid output of the MVR separator 310, and enters the outer evaporation crystallization device for subsequent operation. Preferably, taking calcium chloride waste liquid as an example, the waste liquid is concentrated to 20% to 25% and then discharged from the outer evaporation crystallization device for subsequent operation.

[0055] It is understandable that, during the cyclic evaporation of the waste liquid, the boiling point gradually increases due to the gradual reduction of water content therein, so there is a corresponding relationship between the boiling point and the concentration. The operator can set the heating temperature of the MVR evaporation device 300 according to the actual application requirements, for example, by using MVR compressors 320 of different powers to adjust the steam temperature, and can also connect the raw steam to the shell steam input end of the MVR heater 330 as a startup and supplementary heat source. When the waste liquid no longer boils at the current temperature and the compressor gas volume is insufficient, it can be judged that its concentration has reached the preset standard.

[0056] Specifically, the MVR heater 330 may adopt a vertical shell-and-tube heat exchanger, and the heat exchanger is a 38x1.5mm TA2 tube.

[0057] See also Figure 2 Further, the MVR evaporation device 300 further includes an axial flow pump 311, which is arranged between the MVR separator 310 and the MVR heater 330, and whose waste liquid input end is connected to the waste liquid output end of the MVR separator 310, and whose waste liquid output end is connected to the pipe-side waste liquid input end of the MVR heater 330, for pumping the waste liquid to circulate in the MVR heater 330 and the MVR separator 310. The concentrated waste liquid output end is arranged on the pipeline connected between the axial flow pump 311 and the MVR heater 330.

[0058] Furthermore, at least one of a spherical baffle, a labyrinth demister and a wire mesh demister is disposed in the MVR separator 310 to remove liquid droplets entrained in the steam generated in the MVR separator 310 and reduce corrosion of pipelines and equipment.

[0059] See also Figure 2 In some embodiments, the MVR evaporation device 300 includes a plurality of MVR compressors 320, and the plurality of MVR compressors 320 are connected in series. That is, the steam output end of the current MVR compressor 320 is connected to the steam input end of the next MVR compressor 320, and the steam is continuously heated and pressurized by passing through the plurality of MVR compressors 320 in sequence. The operator can select the number of MVR compressors 320 according to actual application requirements.

[0060] Please continue reading Figure 2 In some embodiments, the MVR evaporation device 300 further includes a gas-liquid separation tank 312, which is disposed between the MVR separator 310 and the MVR compressor 320, wherein the steam input end thereof is connected to the steam output end of the MVR separator 310, the steam output end thereof is connected to the steam input end of the MVR compressor 320, and the liquid output end thereof is connected to the shell-side condensate input end of the exhaust steam condensate preheater 110. The gas-liquid separation tank 312 is used to further remove the liquid droplets entrained in the steam generated by the MVR separator 310.

[0061] Please continue reading Figure 2 In some embodiments, the waste liquid concentration device further includes a steam condensate tank 400, whose input end is respectively connected to the shell-side condensate output end of the MVR heater 330, the liquid output end of the gas-liquid separation tank 312, and the condensate output end of the exhaust steam preheater 120. Its output end is connected to the shell-side condensate input end of the exhaust steam condensate preheater 110. It is used to recover the condensate discharged from the MVR heater 330, the gas-liquid separation tank 312, and the exhaust steam preheater 120 and transport them to the initiating condensate preheater to perform the first stage preheating of the subsequent waste liquid.

[0062] The utility model recovers the condensed water discharged from the preheating device 100 and the MVR evaporation device 300 to perform the first stage preheating of the waste liquid, recovers the exhaust steam generated by the degassing device 200 for the second stage preheating, and only requires live steam as the main heat source during the third stage preheating. In special application scenarios, live steam is required as a supplementary heat source in the MVR evaporation device 300. The heat of the condensed water and exhaust steam generated during the operation of the wastewater concentration device is recovered to the maximum extent, which greatly reduces energy waste and has significant energy-saving effects and economic benefits.

[0063] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations on the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A waste liquid concentration device, characterized in that: include: A preheating device (100), wherein the waste liquid input end thereof is used to communicate with an off-site waste liquid conveying pipeline; A degassing device (200), wherein the waste liquid input end is connected to the waste liquid output end of the preheating device (100); and the gas output end is connected to the gas input end of the preheating device (100), or is used to be connected to the outside; The waste liquid input end of the MVR evaporation device (300) is connected to the waste liquid output end of the degassing device (200); and the concentrated waste liquid output end is used to connect to an off-site evaporation crystallization device.

2. The waste liquid concentration device according to claim 1, characterized in that: The preheating device (100) comprises: An exhaust steam condensate preheater (110), wherein the waste liquid input end thereof is the waste liquid input end of the preheating device (100); and the shell-side condensate input end thereof is connected to the condensate output end of the MVR evaporation device (300); An exhaust steam preheater (120), wherein the waste liquid input end thereof is connected to the waste liquid output end of the exhaust steam condensate preheater (110); the steam input end thereof is connected to the gas output end of the degassing device (200); and the condensate output end thereof is connected to the shell-side condensate input end of the exhaust steam condensate preheater (110); The steam preheater (130) has a waste liquid input end connected to the waste liquid output end of the exhaust steam preheater (120); its waste liquid output end is the waste liquid output end of the preheating device (100); and its steam input end is used to communicate with an external steam transmission pipeline.

3. The waste liquid concentrating device according to claim 2, characterized in that: The degassing device (200) comprises: A degassing tower (210) is provided with a spray pipe at the upper part of its internal cavity, the input end of the spray pipe is the waste liquid input end of the degassing device (200); the gas output end is the gas output end of the degassing device (200), and is connected to the steam input end of the exhaust steam preheater (120); An evaporation feed pump (220) has a waste liquid input end connected to the waste liquid output end of the degassing tower (210); it has a first waste liquid output end and a second waste liquid output end, the first waste liquid output end is connected to the spray pipe; the second waste liquid output end is the waste liquid output end of the degassing device (200).

4. The waste liquid concentrating device according to claim 3, characterized in that: The lower part of the degassing tower (210) is provided with a water tank, and a pH value detection device is installed in the water tank.

5. The waste liquid concentrating device according to claim 3, characterized in that: The MVR evaporation device (300) comprises: The MVR separator (310) has a first waste liquid input end and a second waste liquid input end; the first waste liquid input end is the waste liquid input end of the MVR evaporation device (300), and is connected to the second waste liquid output end of the evaporation feed pump (220); and the concentrated waste liquid output end is used to connect to an off-site evaporation crystallization device; An MVR compressor (320), a steam input end of which is in communication with a steam output end of the MVR separator (310); The MVR heater (330) has a shell-side steam input end connected to the steam output end of the MVR compressor (320); a shell-side condensate output end connected to the shell-side condensate input end of the exhaust steam condensate preheater (110); a tube-side waste liquid input end connected to the waste liquid output end of the MVR separator (310); and a tube-side waste liquid output end connected to the second waste liquid input end of the MVR separator (310).

6. The waste liquid concentrating device according to claim 5, characterized in that: The MVR evaporation device (300) further comprises: An axial flow pump (311) is arranged between the MVR separator (310) and the MVR heater (330), wherein the waste liquid input end of the axial flow pump (311) is connected to the waste liquid output end of the MVR separator (310), and the waste liquid output end of the axial flow pump (311) is connected to the waste liquid input end of the tube side of the MVR heater (330).

7. The waste liquid concentrating device according to claim 5, characterized in that: The MVR separator (310) is provided with at least one of a spherical baffle, a labyrinth demister and a wire mesh demister.

8. The waste liquid concentrating device according to claim 5, characterized in that: The MVR evaporation device (300) comprises a plurality of MVR compressors (320), and the plurality of MVR compressors (320) are connected in series.

9. The waste liquid concentrating device according to claim 5, characterized in that: The MVR evaporation device (300) further comprises: A gas-liquid separation tank (312) is arranged between the MVR separator (310) and the MVR compressor (320), wherein the steam input end thereof is connected to the steam output end of the MVR separator (310); the steam output end thereof is connected to the steam input end of the MVR compressor (320); and the liquid output end thereof is connected to the shell-side condensate input end of the exhaust steam condensate preheater (110).

10. The waste liquid concentrating device according to claim 9, characterized in that: Also includes: An exhaust steam condensate tank (400) has an input end connected to the shell-side condensate output end of the MVR heater (330), the liquid output end of the gas-liquid separation tank (312) and the condensate output end of the exhaust steam preheater (120); and an output end connected to the shell-side condensate input end of the exhaust steam condensate preheater (110).

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