Normal-pressure low-temperature evaporative crystallization device and separation method of industrial waste brine

Abstract

The invention discloses a normal-pressure low-temperature evaporative crystallization device and a separation method of industrial waste brine, and relates to the technical field of evaporative crystallization. By arranging the spiral liquid inlet channel, the heat exchange efficiency of the raw material liquid in the falling film tube is improved. The heated raw material liquid enters the packing layer of the humidifying tower, so that the contact area between the raw material liquid and gas in the humidifying tower can be increased, the evaporation efficiency of a solvent in the raw material liquid is improved, and the crystallization process after the raw material liquid enters an evaporation crystallizer is facilitated. The gas with higher temperature in the tower carries the solvent in the raw material liquid to enter the dehumidification tower through the first gas outlet, the content of the liquid carried in the gas is reduced, and then the gas returns to the humidification tower to be recycled. The device can operate in a normal pressure state, is low in operation condition requirement and high in economic benefit, realizes non-boiling evaporation of a solvent in the humidifying tower by being matched with an integrated structure of the humidifying tower, reduces the operation temperature, remarkably improves the resource utilization rate, and meets the development requirements of clean production and circular economy.

Description

Technical Field

[0001] The present invention relates to the technical field of evaporation and crystallization, and in particular to a normal-pressure and low-temperature evaporation and crystallization device and a method for separating industrial waste brine. Background Art

[0002] The production of chemical materials often generates a significant amount of washing wastewater, often containing high levels of salt, such as sodium chloride and sodium sulfate. This wastewater must be treated to remove the salt before it can be discharged. Therefore, recovering and treating the salt in this saline wastewater is crucial to ensuring the sustainable production of chemical materials.

[0003] The current treatment method for saline washing wastewater is generally to separate the solid salt from the water through evaporation and crystallization. However, traditional treatment methods often use high-temperature and / or high-pressure evaporation and crystallization equipment and processes, such as MVR evaporators, which require a large amount of heat source and high energy consumption. At the same time, evaporation and crystallization under high-temperature conditions not only have requirements for the saline washing wastewater to be treated, but can only treat saline washing wastewater that is not sensitive to temperature. The structure of temperature-sensitive salts will be destroyed at high temperatures, making them difficult to recycle. It also has requirements for the equipment materials, which must be high-temperature resistant. Some processes even use vacuum evaporation and crystallization equipment to treat saline washing wastewater, which seriously increases the investment cost of the equipment. Since saline washing wastewater is not the target product of chemical material production, if the cost of its environmental post-treatment is high, it will limit the production process of chemical materials.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a normal pressure low temperature evaporation crystallization device and a method for separating industrial waste brine.

[0006] The present invention is achieved in that: In a first aspect, the present invention provides a normal-pressure low-temperature evaporation crystallization device, comprising a raw liquid storage tank, a humidification tower, a dehumidification unit, and a separation unit.

[0007] The humidification tower includes a falling film pipe section, a humidification tower packing layer and an evaporation crystallizer which are arranged in sequence from top to bottom and integrated into one. A first raw liquid inlet is provided on the side of the humidification tower close to the falling film pipe section, and the first raw liquid inlet is connected to the raw liquid storage tank through a pipeline.

[0008] The falling film tube portion includes a falling film tube liquid distributor and a falling film tube body. The falling film tube body includes a first heat exchange channel and a second heat exchange channel. The falling film tube liquid distributor includes a liquid distribution pipe. A spiral liquid inlet channel is provided at one end of the liquid distribution pipe. The falling film tube liquid distributor is connected to the first heat exchange channel through the spiral liquid inlet channel, and the second heat exchange channel is connected to an external heat medium source.

[0009] The dehumidification unit includes a dehumidification tower, which includes a second gas inlet and a second gas outlet; the humidification tower is also provided with a first gas inlet on the side close to the falling film tube portion, and the evaporation crystallizer is provided with a first gas outlet on the side close to the packing layer of the humidification tower. The first gas outlet and the second gas inlet are connected, and the second gas outlet and the first gas inlet are connected, so that the humidification tower and the dehumidification tower are connected.

[0010] A salt solution outlet is provided on one side of the evaporation crystallizer away from the first gas outlet. The salt solution outlet is connected to the separation unit through a pipeline. The liquid separated by the separation unit is returned to the humidification tower.

[0011] In an optional embodiment, the evaporation crystallizer includes an evaporation zone, a mixing zone and a crystallization zone connected in sequence, the evaporation zone is connected to the humidification tower packing layer, a crystal grower is provided in the crystallization zone, and the opening at the bottom of the crystallization zone is a salt solution outlet.

[0012] And / or, the outer shell of the mixing zone is conical, the crystal grower is a V-shaped crystal grower, the edge of the V-shaped crystal grower is spaced apart from the wall of the crystallization zone, and the crystallization zone is also provided with a second raw liquid inlet, the second raw liquid inlet is located above the V-shaped crystal grower, and the second raw liquid inlet is connected to the raw liquid storage tank through a pipeline.

[0013] And / or, the V-shaped cone angle of the V-shaped crystal grower is 120-165°.

[0014] And / or, a visual window is further provided on the crystallization area, and the visual window is located above the crystal grower.

[0015] And / or, the evaporation crystallizer is further provided with a clear liquid outlet, which is located between the salt solution outlet and the first gas outlet and is connected to the first raw liquid inlet of the humidification tower through a pipeline.

[0016] In an optional embodiment, a gas opening adjustment component is provided at the first gas outlet, and the gas opening adjustment component includes any one of a louver adjustment component or a positioning pin.

[0017] And / or, the shutter-type adjustment assembly includes a fixing member having a plurality of openings formed thereon, and an adjusting member is provided on the surface of each opening, and the adjusting member can selectively move relative to the fixing member to open or close the opening.

[0018] And / or, the number of the openings on the fixing member is at least two.

[0019] And / or, a humidifying tower demister is further provided at the first gas outlet, and the humidifying tower demister is located below the gas opening adjustment assembly.

[0020] And / or, the humidification tower demister includes any one of a wire mesh demister or a spray head.

[0021] In an optional embodiment, the falling film tube liquid distributor also includes a liquid distribution tube support and a liquid distribution tube cap. The liquid distribution tube support is fixed in the humidification tower. The liquid distribution tube is fixedly connected to the liquid distribution tube support, and a first inlet of a spiral liquid inlet channel is provided at the connection. The end of the liquid distribution tube away from the spiral liquid inlet channel is sealed by the liquid distribution tube cap.

[0022] And / or, the inner diameter of the first heat exchange channel is larger than the outer diameter of the liquid distribution pipe, so that the spiral liquid inlet channel is located inside the first heat exchange channel.

[0023] And / or, one end of the liquid distribution pipe having the spiral liquid inlet channel is a bell mouth.

[0024] And / or, the inner wall surface of the spiral liquid inlet channel is provided with a hydrophilic wear-resistant coating.

[0025] And / or, the hydrophilic wear-resistant coating includes any one of a carbon nanotube-ceramic composite coating and a silicon carbide coating.

[0026] In an optional embodiment, the humidification tower is further provided with an ultrasonic generator, which is arranged corresponding to the falling film tube portion.

[0027] And / or, the ultrasonic generator is located on the outer surface of the humidification tower.

[0028] And / or, the normal pressure low temperature evaporation crystallization device further includes a plurality of detectors, the detectors including at least one of a pressure detector, a temperature detector, a flow detector and a wind speed detector.

[0029] In an optional embodiment, a humidifying tower spray head is further provided in the humidifying tower. The humidifying tower spray head is located above the falling film tube portion and is connected to the first raw material liquid inlet through a pipeline.

[0030] And / or, the first gas inlet is located at the top of the humidification tower, and a gas distributor is further provided in the humidification tower, and the gas distributor is located below the first gas inlet.

[0031] In an optional embodiment, the dehumidification unit further includes a heat exchanger, and the dehumidification tower is connected to the heat exchanger through a pipeline to cool the gas in the dehumidification tower.

[0032] And / or, a dehumidification tower packing layer is provided in the dehumidification tower, a dehumidification tower spray head is provided above the dehumidification tower packing layer, the dehumidification tower spray head is connected to the outlet of the heat exchanger through a pipeline, and the dehumidification tower is also provided with a solution outlet, which is connected to the inlet of the heat exchanger.

[0033] And / or, there are multiple dehumidification tower packing layers, a dehumidification tower spray head is provided above each dehumidification tower packing layer, and each dehumidification tower spray head is connected to the outlet of the heat exchanger through a pipeline.

[0034] And / or, the dehumidification unit further includes a solution buffer tank, the inlet of the solution buffer tank is communicated with the solution outlet, and the outlet of the solution buffer tank is communicated with the inlet of the heat exchanger.

[0035] And / or, a solution circulation pump is further provided on the pipeline connecting the outlet of the solution buffer tank and the inlet of the heat exchanger.

[0036] And / or, the outlet of the solution buffer tank is also connected to an external liquid pipeline.

[0037] And / or, an induced draft fan is provided on the pipeline communicating between the first gas outlet and the second gas inlet and / or the pipeline communicating between the second gas outlet and the first gas inlet.

[0038] In an alternative embodiment, the separation unit comprises at least one of a cyclone, a thickener, and a centrifuge.

[0039] And / or, the separation unit includes a cyclone, a thickener and a centrifuge, the inlet of the cyclone is connected to the brine outlet of the humidification tower through a pipeline, the solid outlet of the cyclone is connected to the inlet of the thickener, the solid outlet of the thickener is connected to the inlet of the centrifuge, and the cyclone, thickener and centrifuge are all provided with a liquid outlet, and the liquid outlets are all connected to the first raw liquid inlet of the humidification tower.

[0040] And / or, the separation unit further includes a liquid storage tank, the liquid outlet is connected to the liquid storage tank via a pipeline, and the liquid storage tank is further connected to the first raw liquid inlet via a pipeline.

[0041] And / or, a liquid delivery pump is further provided on the pipeline connecting the liquid storage tank and the first raw liquid inlet.

[0042] And / or, a humidification tower discharge pump is provided on the pipeline connecting the cyclone and the salt solution outlet.

[0043] In the second aspect, the present invention provides a method for separating industrial waste brine, which is suitable for a normal pressure low-temperature evaporation crystallization device as in any of the aforementioned embodiments, including passing the raw liquid into a humidification tower, the raw liquid is evenly distributed through a falling film tube liquid distributor, and rotates through a spiral liquid inlet channel into the first heat exchange channel of the falling film tube body, and is heated after heat exchange with the heat medium in the second heat exchange channel in the first heat exchange channel.

[0044] The heated raw liquid passes through the packing layer of the humidifying tower and enters the evaporation crystallizer. The heated raw liquid crystallizes in the evaporation crystallizer. The crystals obtained from the crystallization and the liquid in the evaporation crystallizer enter the separation unit for solid-liquid separation. The liquid separated by the separation unit is returned to the humidifying tower for recycling.

[0045] The heated raw liquid increases the gas temperature in the evaporation crystallizer, thereby increasing the water content of the gas in the evaporation crystallizer. The gas flows from the first gas outlet of the evaporation crystallizer into the dehumidification tower to remove moisture and then returns to the humidification tower for recycling.

[0046] The raw liquid to be treated contacts the gas in the humidification tower in downstream flow.

[0047] In an optional embodiment, the method for removing moisture in the dehumidification tower is to cool the gas from the evaporation crystallizer.

[0048] And / or, the solid-liquid separation method of the separation unit includes at least one of centrifugation, sedimentation and filtration.

[0049] The present invention has the following beneficial effects: The present invention provides a normal pressure low temperature evaporation crystallization device and a method for separating industrial waste brine. By integrating the falling film tube, the humidification tower packing layer and the evaporation crystallizer in the humidification tower, the on-site installation period and the floor space occupied are significantly reduced, and the rapid deployment requirements under different environmental conditions can be adapted, thereby reducing the difficulty of engineering implementation. By providing a spiral liquid inlet channel, the raw material liquid is spirally introduced into the first heat exchange channel of the falling film tube, thereby increasing the distance the raw material liquid flows through in the falling film tube. At the same time, the raw material liquid hits the inner wall surface of the first heat exchange channel during the spiral process in the first heat exchange channel, thereby increasing the turbulence degree of the raw material liquid and improving the heat exchange efficiency of the raw material liquid in the falling film tube. The heated raw material liquid enters the humidification tower packing layer, thereby increasing the contact area between the raw material liquid and the gas in the humidification tower, improving the evaporation efficiency of the solvent in the raw material liquid, and the evaporated solvent is captured by the higher temperature gas in the humidification tower, thereby reducing the solvent content in the raw material liquid, which is beneficial to the crystallization process after the raw material liquid enters the evaporation crystallizer. The gas with a higher temperature in the tower carries the solvent in the raw liquid into the dehumidification tower through the first gas outlet. Based on the characteristic that the saturated humidity of the air changes with temperature, the liquid content carried in the gas is reduced, and then the gas is returned to the humidification tower for recycling. The device can operate under normal pressure, using the air in the device as a carrier gas, so that the air can carry away the solvent in the raw liquid in the humidification tower, and then remove the solvent in the dehumidification tower, and return it to the humidification tower for recycling. The operating conditions are low, and the device has high economic benefits as a device for recycling and treating salt-containing washing wastewater. At the same time, because the device uses air as a carrier gas, it cooperates with the integrated structure of the humidification tower to achieve non-boiling evaporation of the solvent in the humidification tower, and the operating temperature is reduced. This not only avoids the damage of high temperature to heat-sensitive salt materials, but also reduces the material requirements of the equipment, so that the equipment materials of the device are not limited to metal materials, and plastics with a certain strength, such as polypropylene materials, can also be used, which significantly improves resource utilization and meets the development requirements of clean production and circular economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0051] Figure 1 A schematic structural diagram of a normal-pressure low-temperature evaporation crystallization device provided in an embodiment of the present invention; Figure 2 A schematic structural diagram of a humidification tower provided in an embodiment of the present invention; Figure 3 A schematic structural diagram of a falling film tube portion provided in an embodiment of the present invention; Figure 4 Schematic diagram of the structure of the falling film tube liquid distributor provided by the embodiment of the present invention Figure 1 ; Figure 5 A schematic structural diagram of an evaporation crystallizer provided in an embodiment of the present invention; Figure 6 A schematic diagram of the upper structure of an evaporation crystallizer provided in an embodiment of the present invention; Figure 7 A schematic structural diagram of a louver-type adjustment assembly provided in an embodiment of the present invention; Figure 8 A schematic structural diagram of a dehumidification tower provided in an embodiment of the present invention; Figure 9 This is a diagram showing the operating principle of the atmospheric pressure low-temperature evaporation crystallization device provided in an embodiment of the present invention.

[0052] Explanation of the main component symbols: 10-normal pressure low temperature evaporation crystallization device; 100-raw material storage tank; 200-humidification tower; 210-falling film pipe; 211-falling film pipe liquid distributor; 2111-liquid distribution pipe; 2112-spiral liquid inlet channel; 2113-liquid distribution pipe support; 2114-liquid distribution pipe cap; 2115-first inlet; 212-falling film pipe body; 2121-first heat exchange channel; 2122-second heat exchange channel outlet; 2123-second heat exchange channel inlet; 220-humidification tower packing layer; 230-evaporation crystallizer; 231-salt liquid outlet; 232-evaporation zone; 233-mixing zone; 234-crystallization zone; 241-first raw material liquid inlet; 242-first gas inlet; 243-first gas outlet; 244-second raw material liquid inlet; 245-clear liquid outlet; 250-louver adjustment component ; 251-fixing member; 252-adjusting member; 260-humidifying tower demister; 270-ultrasonic generator; 280-humidifying tower spray head; 290-gas distributor; 300-dehumidification unit; 310-dehumidification tower; 311-second gas inlet; 312-second gas outlet; 313-dehumidification tower packing layer; 314-dehumidification tower spray head; 315-solution outlet; 316-dehumidification tower demister; 32 0-heat exchanger; 330-solution buffer tank; 340-solution circulation pump; 400-separation unit; 410-cyclone; 420-thickener; 430-centrifuge; 450-liquid storage tank; 460-liquid delivery pump; 500-induced draft fan; 600-humidification tower discharge pump; 700-V-shaped crystal grower; 710-V-shaped crystal grower bracket; 800-solid salt storage tank; 20-external liquid pipeline. DETAILED DESCRIPTION

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the following will clearly and completely describe the technical solutions of the embodiments of the present invention with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0054] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0055] 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, it does not need to be further defined or explained in subsequent drawings.

[0056] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" and the like indicate positions or locations based on the positions shown in the accompanying drawings, or the positions or locations in which the inventive product is typically placed when in use. These terms are intended solely to facilitate the description of the present invention and to simplify the description, and are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third," etc., are used solely to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0057] Furthermore, terms such as "horizontal" and "vertical" do not necessarily mean that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0058] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0059] First, please refer to Figure 1 This embodiment provides a normal-pressure low-temperature evaporation crystallization device 10 , which includes a raw liquid storage tank 100 , a humidification tower 200 , a dehumidification unit 300 and a separation unit 400 .

[0060] Please refer to Figure 2 The humidifying tower 200 includes a falling film pipe portion 210, a humidifying tower packing layer 220 and an evaporation crystallizer 230, which are arranged in sequence from top to bottom and integrated into one body. The humidifying tower 200 is provided with a first raw liquid inlet 241 on the side close to the falling film pipe portion 210, that is, the upper part of the humidifying tower 200. The first raw liquid inlet 241 is connected to the raw liquid storage tank 100 through a pipeline.

[0061] Please refer to Figure 3 The falling film tube portion 210 includes a falling film tube body 212, and the falling film tube body 212 includes a first heat exchange channel 2121 and a second heat exchange channel. The first heat exchange channel 2121 and the second heat exchange channel have a wall for heat exchange. The first heat exchange channel 2121 is used to circulate the raw material liquid to be treated, and the second heat exchange channel is connected to an external heat medium source so that the raw material liquid to be treated is heated after passing through the falling film tube body 212.

[0062] Since the normal pressure and low temperature evaporation crystallization device 10 provided in the embodiment of the present invention adopts a non-boiling evaporation method to realize the evaporation crystallization process under normal pressure and low temperature conditions, compared with traditional high temperature evaporation, in the embodiment of the present invention, the external heat medium source connected to the falling film tube body 212 is not limited to the use of specially prepared high temperature steam, and can also directly utilize the residual heat sources in other process flows, such as secondary steam, steam condensate and exhaust steam and other low-quality heat sources generated by the distillation process, thereby improving the utilization rate of heat. The heating process of the raw material liquid to be processed does not require additional consumption costs, and has excellent economic benefits.

[0063] Preferably, the external heat medium source connected to the falling film tube body 212 is a residual heat source in other process flows.

[0064] Preferably, the surface area of the falling film tube body 212 can be 8 to 12 m 2 .

[0065] In order to ensure that the raw material liquid to be processed is evenly distributed in the falling film tube and to ensure the temperature increase effect of the raw material liquid to be processed, the falling film tube portion 210 further includes a falling film tube liquid distributor 211 .

[0066] In such Figure 3 and Figure 4 In the embodiment shown, in order to ensure the installation stability of the falling film tube portion 210, the falling film tube liquid distributor 211 also includes a liquid distribution tube support 2113, which is fixed to the inner wall surface of the humidification tower 200, and the thickness of the liquid distribution tube support 2113 is 14~18 mm.

[0067] The falling film tube liquid distributor 211 includes a liquid distribution tube 2111, and a spiral liquid inlet channel 2112 is provided at one end of the liquid distribution tube 2111. The falling film tube liquid distributor 2111 is connected to the first heat exchange channel 2121 through the spiral liquid inlet channel 2112. By providing the spiral liquid inlet channel 2112, the raw material liquid to be processed enters the first heat exchange channel 2121 of the falling film tube in a spiral manner, thereby increasing the distance the raw material liquid flows in the falling film tube. At the same time, the raw material liquid hits the inner wall surface of the first heat exchange channel 2121 during the spiral process in the first heat exchange channel 2121, which can also increase the turbulence degree of the raw material liquid and improve the heat exchange efficiency of the raw material liquid in the falling film tube.

[0068] The liquid distribution pipe 2111 is fixedly connected to the liquid distribution pipe support 2113, and a first inlet 2115 of a spiral liquid inlet channel 2112 is opened at the connection. The opening depth of the first inlet 2115 is 10-15 mm.

[0069] Among them, the liquid distribution pipe support 2113 and the inner wall surface of the humidification tower 200 can be connected by welding, bolt connection, etc., and multiple liquid distribution pipes 2111 can also be welded on the liquid distribution pipe support 2113, as long as the first inlet 2115 of the spiral liquid inlet channel 2112 is not blocked.

[0070] There are multiple liquid distribution pipes 2111, and there are also multiple corresponding first heat exchange channels 2121. The multiple liquid distribution pipes 2111 are arranged in a one-to-one correspondence with the multiple first heat exchange channels 2121. The multiple liquid distribution pipes 2111 are evenly spaced on the liquid distribution pipe support 2113. To ensure good mass transfer and avoid insufficient mass transfer due to too few liquid distribution pipes 2111, or increased costs and reduced evaporation efficiency due to too many liquid distribution pipes 2111, the optimal number of liquid distribution pipes 2111 is between 60 and 80.

[0071] Furthermore, in order to ensure that the raw liquid to be processed enters the falling film tube from the first inlet 2115, the falling film tube liquid distributor 211 also includes a liquid distribution tube cap 2114, and the end of the liquid distribution tube 2111 away from the spiral liquid inlet channel 2112 is sealed by the liquid distribution tube cap 2114.

[0072] In a preferred embodiment, the spiral liquid inlet channel 2112 is located on the outer surface of the liquid distribution pipe 2111, and the inner diameter of the first heat exchange channel 2121 is larger than the outer diameter of the liquid distribution pipe 2111, so that the spiral liquid inlet channel 2112 is located inside the first heat exchange channel 2121. When the raw material liquid to be processed enters the first heat exchange channel 2121 through the first inlet 2115, most of the raw material liquid will enter the spiral liquid inlet channel 2112 along a spiral shape, and a small amount of raw material liquid will be thrown out of the spiral liquid inlet channel 2112 due to excessive centrifugal force, contact the inner wall surface of the first heat exchange channel 2121 and rebound, thereby increasing the turbulence of the raw material liquid and reducing the dynamic viscosity of the raw material liquid, which is conducive to the diffusion of solvent molecules in the raw material liquid into the gas, increasing the possibility of gas capturing solvent in the humidification tower 200, and facilitating the subsequent crystallization process.

[0073] In a further preferred embodiment, the liquid distribution pipe 2111 has a spiral liquid inlet channel 2112 with a bell mouth at one end, which increases the rotational power of the raw material liquid in the first heat exchange channel 2121 and increases the heat exchange capacity between the raw material liquid and the heat medium in the second heat exchange channel.

[0074] In a preferred embodiment, since the raw material liquid to be processed is mostly a salt solution, in order to prevent a small amount of salt from crystallizing in the falling film tube portion 210 during the evaporation and crystallization process, thereby blocking the spiral liquid inlet channel 2112, a hydrophilic and wear-resistant coating is provided on the inner wall surface of the spiral liquid inlet channel 2112, for example, it can be any one of a carbon nanotube-ceramic composite coating or a silicon carbide coating.

[0075] Please refer to Figure 2 Furthermore, an ultrasonic generator 270 may be provided on the humidification tower 200, and the ultrasonic generator 270 is provided corresponding to the falling film tube portion 210. The ultrasonic generator 270 not only serves as an active enhancement measure to promote the evaporation of the raw material liquid to be processed, reducing the dynamic viscosity of the raw material liquid and facilitating the diffusion of the solvent into the gas, but also enhances the cavitation effect of the raw material liquid to be processed within the falling film tube body 212, greatly enhancing the anti-scaling effect.

[0076] The combined presence of ultrasonic generator 270 and the hydrophilic, wear-resistant coating significantly reduces scaling of the falling film tube 210, particularly the spiral liquid inlet channel 2112. The ultrasonic generator 270 and spiral liquid inlet channel 2112 are located within the first heat exchange channel 2121, and the liquid distribution tube 2111 has a bell-shaped end at one end of the spiral liquid inlet channel 2112. This significantly reduces the dynamic viscosity of the feedstock liquid, facilitating diffusion of the solvent into the gas and, in turn, facilitating subsequent crystallization.

[0077] In a preferred embodiment, the ultrasonic generator 270 is located on the outer surface of the humidification tower 200 .

[0078] In a preferred embodiment, the unit power of the ultrasonic generator 270 is 20-50w / m 2 , frequency is 20~40Hz.

[0079] In a preferred embodiment, in order to ensure uniform distribution of the raw liquid to be processed in the falling film pipe section 210, a humidifying tower spray head 280 is also provided in the humidifying tower 200. The humidifying tower spray head 280 is located above the falling film pipe section 210 and is connected to the first raw liquid inlet 241 through a pipeline.

[0080] The raw material liquid to be treated is heated in the falling film tube section 210, so the temperature of the gas (such as air) in the humidification tower 200 is also increased, and the water carrying capacity of the gas is improved. In addition, the structural design of the falling film tube section 210 causes the solvent in the raw material liquid to be treated to transfer to the gas, and the water content in the heated raw material liquid is reduced, which is conducive to subsequent crystallization.

[0081] The raw material liquid with higher temperature enters the humidification tower packing layer 220, and the volume of the humidification tower packing layer 220 is 0.1~0.3m 3 , with a specific surface area of 120~180 m 2 / m 3 The humidifying tower packing layer 220 may be filled with regular corrugated packing, and the material may be any one of PP, PVC or ceramic.

[0082] The humidifying tower packing layer 220 is located between the falling film tube portion 210 and the evaporation crystallizer 230. By setting the humidifying tower packing layer 220, the heated raw material liquid is distributed in the humidifying tower packing layer 220, increasing the gas-liquid contact area and further improving the ability of the solvent in the raw material liquid to transfer into the gas.

[0083] The raw material liquid passing through the humidifying tower packing layer 220 enters the evaporation crystallizer 230 below it for crystallization.

[0084] Please refer to Figure 2 The evaporation crystallizer 230 includes an evaporation zone 232, a mixing zone 233 and a crystallization zone 234 which are connected in sequence. The evaporation zone 232 is connected to the humidification tower packing layer 220. A crystal grower is provided in the crystallization zone 234. The opening at the bottom of the crystallization zone 234 is a salt solution outlet 231.

[0085] The raw liquid that has passed through the packing layer 220 of the humidifying tower accumulates in the evaporation crystallizer 230, and the solid solute crystals are precipitated. The precipitated crystals collide with each other and grow in the evaporation crystallizer 230, and then sink into the crystallization zone 234. Solid salts of sufficient size are screened out at the crystal grower in the crystallization zone 234, and flow out from the salt liquid outlet 231 at the bottom of the crystallization zone 234. The salt liquid outlet 231 is connected to the separation unit 400 through a pipeline. The liquid separated by the separation unit 400 is returned to the humidifying tower 200 for reuse to improve the desalination capacity of the raw liquid.

[0086] Please refer to Figure 5 In a preferred embodiment, the outer shell of the mixing zone 233 is conical in shape, the crystal grower is a V-shaped crystal grower 700, the V-shaped crystal grower 700 is fixed in the crystallization zone by a V-shaped crystal grower bracket 710, the edge of the V-shaped crystal grower 700 is spaced apart from the wall of the crystallization zone 234, and the crystallization zone 234 is also provided with a second raw liquid inlet 244, the second raw liquid inlet 244 is located above the V-shaped crystal grower 700, and the second raw liquid inlet 244 is connected to the raw liquid storage tank 100 through a pipeline.

[0087] By configuring the outer shell of the mixing zone 233 to be conical and in conjunction with the V-shaped crystal grower 700, crystals precipitated from the raw material liquid in the evaporation crystallizer 230 can be directed within the mixing zone 233 to the V-shaped crystal grower 700 for grain screening. The V-shaped crystal grower 700, in conjunction with the structural design of the second raw material liquid inlet 244, allows the small amount of raw material liquid entering from the second raw material liquid inlet 244 to purge the grains in the V-shaped crystal grower 700. Smaller, lighter grains are lifted by the raw material liquid and continue to collide and grow in the solution, while larger, heavier grains remain within the V-shaped crystal grower 700, waiting to be discharged to the separation unit 400 for solid-liquid separation.

[0088] In a preferred embodiment, the V-shaped cone angle of the V-shaped crystal grower 700 is 120-165°, more preferably 150-165°, and most preferably 165°. By controlling the V-shaped cone angle of the V-shaped crystal grower 700 within the above range, the growth of the grains is facilitated.

[0089] In a preferred embodiment, a viewing window (not shown in the figure, for example, the viewing window can be made of transparent glass or transparent industrial plastic) is provided in the crystallization zone 234. The viewing window is located above the crystal grower. The viewing window allows observation of the crystal grains within the V-shaped crystal grower 700, thereby facilitating the determination of the time when the liquid within the evaporation crystallizer 230 is discharged into the separation unit 400.

[0090] Please continue to refer to Figure 2 , and / or, the evaporation crystallizer 230 is further provided with a clear liquid outlet 245, which is located in the mixing zone 233 and is connected to the first raw liquid inlet 241 of the humidification tower 200 through a pipeline.

[0091] Since solid crystals will appear after the heated raw liquid enters the evaporator crystallizer 230, the solid crystals will settle downward due to gravity, that is, they will accumulate in the crystallization zone 234. The upper part of the solution in the mixing zone 233 has a low salt content. By transporting this part of the liquid with a low salt content back to the first raw liquid inlet 241 for circulation treatment, not only can the overall temperature in the humidification tower 200 be kept stable, and the temperature drop in the humidification tower 200 after a period of time can be avoided to affect the crystallization process, but the water in this part of the clear liquid can be returned to the falling film tube part 210 for heating, so that more solvent is transferred to the gas, further improving the crystallization ability of the raw liquid.

[0092] Due to the design of the falling film tube 210 in the humidifying tower 200, the overall temperature in the humidifying tower 200 is relatively high, so the water carrying capacity of the gas in the humidifying tower 200 is increased. Through the design of the ultrasonic generator 270, the falling film tube 210 and the humidifying tower packing layer 220, more solvent in the raw material liquid is transferred to the gas, and the gas in the humidifying tower 200 is hot saturated moisture.

[0093] Please refer to Figure 1 、 Figure 2 and Figure 8A first gas outlet 243 is provided on the side of the evaporation crystallizer 230 close to the humidification tower packing layer 220, that is, the evaporation zone 232 of the evaporation crystallizer 230 is provided with the first gas outlet 243; a first gas inlet 242 is also provided on the side of the humidification tower 200 close to the falling film tube portion 210, and the dehumidification unit 300 includes a dehumidification tower 310, and the dehumidification tower 310 includes a second gas inlet 311 and a second gas outlet 312. The first gas outlet 243 and the second gas inlet 311 are connected, and the second gas outlet 312 and the first gas inlet 242 are connected, so that the humidification tower 200 and the dehumidification tower 310 are connected, thereby realizing the normal pressure gas circulation in the humidification tower 200 and the dehumidification tower 310.

[0094] The hot saturated wet gas that has absorbed the solvent in the humidifying tower 200 flows out from the first gas outlet 243 of the evaporation zone 232 and enters the dehumidifying tower 310 from the second gas inlet 311. After being processed by the dehumidifying tower 310, the moisture content in the hot saturated wet gas is reduced, and the solvent and gas in the hot saturated wet gas are separated in the dehumidifying tower 310. The gas returns to the humidifying tower 200 for recycling. The salt content in the solvent is extremely low, the conductivity is 100~120μs / cm, and the purity is high, meeting the external discharge standards. It can be directly discharged or connected to other processes (for example, returned to the production system of chemical materials) for reuse.

[0095] Please refer to Figure 8 In some preferred embodiments, in order to adapt to the process of the normal pressure low temperature evaporation crystallization device 10, the second gas inlet 311 is located at the lower part of the dehumidification tower 310, and the second gas outlet 312 is located at the upper part of the dehumidification tower 310. The gas can be naturally overflowed in the dehumidification tower 310 to achieve gas circulation.

[0096] Please refer to Figure 2 At the same time, first gas outlet 243 is located in evaporation zone 232 of evaporation crystallizer 230. Therefore, it is understandable that first gas outlet 243 is located at the lower portion of humidification tower 200. To ensure effective gas-liquid contact, first gas inlet 242 is located at the top of humidification tower 200, resulting in a co-current gas-liquid contact process within humidification tower 200. The raw material liquid maintains a low concentration during evaporation, reducing material viscosity and ion supersaturation, and suppressing scaling at the source. Therefore, the positioning of first gas outlet 243 and first gas inlet 242 also contributes to the anti-scaling effect of falling film tube section 210.

[0097] In some preferred embodiments, in order to ensure uniform distribution of gas in the humidification tower 200 , a gas distributor 290 is further provided in the humidification tower 200 . The gas distributor 290 is located below the first gas inlet 242 .

[0098] Please refer to Figure 6 and Figure 7In some embodiments, in order to adjust and control the content of the gas in the humidification tower 200, a gas opening adjustment component is provided at the first gas outlet 243, and the gas opening adjustment component includes either a louver adjustment component 250 or a positioning pin.

[0099] In some preferred embodiments, the gas opening adjustment component is a louver-type adjustment component 250, which includes a fixing member 251 having multiple openings. The surface of each opening is provided with an adjustment member 252, and the adjustment member 252 can selectively move relative to the fixing member 251 to open or close the opening, thereby adjusting the opening degree of the opening on the fixing member 251, thereby adjusting the flow rate of gas entering the dehumidification tower 310 from the humidification tower 200.

[0100] In some preferred embodiments, the opening degree of the opening can be adjusted from 0° to 90°, and the higher the degree, the larger the opening degree.

[0101] The movement process of the adjusting member 252 of the louver-type adjusting assembly 250 relative to the fixing member 251 can be adjusted by the existing structure.

[0102] In some embodiments, the number of openings on the fixing member 251 is at least two, preferably 5 to 15, and more preferably 5 to 10.

[0103] In some embodiments, the first gas outlet 243 is an annular structure on the upper portion of the evaporation crystallizer 230 , and the fixing member 251 and the adjusting member 252 are disposed in the first gas outlet 243 . Therefore, the fixing member 251 is annular and the adjusting member 252 is fan-shaped.

[0104] Please refer to Figure 6 In some preferred embodiments, a humidification tower demister 260 is further provided at the first gas outlet 243. This demister 260 is located below the gas opening adjustment assembly. After the gas enters the first gas outlet 243 from the evaporation zone 232, it must first pass through the humidification tower demister 260 to remove small liquid droplets entrained in the gas. This prevents salt from the small droplets from entering the dehumidification tower 310 along with the gas, thereby ensuring the purity of the liquid separated in the dehumidification tower 310.

[0105] In an optional embodiment, the humidifying tower demister 260 includes either a wire mesh demister or a spray head, and the thickness of the wire mesh demister is 40-80 mm.

[0106] Please refer to Figure 1In some preferred embodiments, an induced draft fan 500 is provided on the pipe connecting the first gas outlet 243 and the second gas inlet 311 and / or the pipe connecting the second gas outlet 312 and the first gas inlet 242 to assist in recycling the gas in the humidification tower 200 and the dehumidification tower 310, and to remove the solvent in the humidification tower 200 for separation.

[0107] Preferably, the induced draft fan 500 can be a mixed-flow ducted induced draft fan 500 with an external motor, wherein the fan shaft is connected to the external motor via a drive shaft. In other embodiments, the induced draft fan 500 can also be another type of induced draft fan 500, as long as the gas in the humidification tower 200 and the dehumidification tower 310 can circulate at normal pressure.

[0108] In some preferred embodiments, dehumidification tower 310 removes moisture from the hot, saturated wet gas by changing the gas temperature. Since higher gas temperatures have greater water-carrying capacity, and lower gas temperatures have less water-carrying capacity, lowering the temperature of the hot, saturated wet gas within dehumidification tower 310 can separate the solvent from the hot, saturated wet gas. The resulting gas is cold, saturated wet gas, which has a lower water content than the hot, saturated wet gas, thereby separating the solvent from the feedstock liquid.

[0109] Therefore, the dehumidification unit 300 further includes a heat exchanger 320 , and the dehumidification tower 310 is connected to the heat exchanger 320 via a pipeline to cool the gas in the dehumidification tower 310 .

[0110] Please refer to Figure 8 In some preferred embodiments, in order to ensure the cooling effect of the hot saturated moisture, a dehumidification tower packing layer 313 is provided in the dehumidification tower 310, and a dehumidification tower spray head 314 is provided above the dehumidification tower packing layer 313. The dehumidification tower spray head 314 is connected to the outlet of the heat exchanger 320 through a pipeline. The dehumidification tower 310 is also provided with a solution outlet 315, and the solution outlet 315 is connected to the inlet of the heat exchanger 320.

[0111] It can be understood that the outlet and inlet of the heat exchanger 320 are both for introducing gas, and the heat exchanger 320 should also have an inlet and outlet for heat exchange medium to achieve a cooling process for the gas.

[0112] In some preferred embodiments, in order to reduce the water content in the hot saturated wet air as much as possible, there are multiple dehumidification tower packing layers 313, and a dehumidification tower spray head 314 is arranged above each dehumidification tower packing layer 313, and each dehumidification tower spray head 314 is connected to the outlet of the heat exchanger 320 through a pipe.

[0113] In some preferred embodiments, the volume of each dehumidification tower packing layer 313 is 0.2~0.4m 3, with a specific surface area of 120~180 m 2 / m 3 The filler filled in the dehumidification tower filler layer 313 can be a regular corrugated filler, and the material can be any one of PP, PVC or ceramic.

[0114] In some preferred embodiments, a dehumidification tower demister 316 is further provided in the dehumidification tower 310 . The dehumidification tower demister 316 is provided above the dehumidification tower packing layer 313 to filter out small water droplets when the gas passes through the dehumidification tower demister 316 .

[0115] In some preferred embodiments, a dehumidification tower spray head 314 is also provided above the dehumidification tower demister 316. The dehumidification tower demister 316 is a wire mesh demister, and the thickness of the dehumidification tower demister 316 is 40-80 mm.

[0116] In some preferred embodiments, the solution outlet 315 is located at the bottom of the dehumidification tower 310 , so that the separated solvent falls by gravity and is discharged from the solution outlet 315 .

[0117] Please refer to Figure 1 In some preferred embodiments, to improve the heat exchange efficiency of heat exchanger 320, dehumidification unit 300 further includes a solution buffer tank 330. The inlet of solution buffer tank 330 is connected to solution outlet 315, and the outlet of solution buffer tank 330 is connected to the inlet of heat exchanger 320. The solvent separated by dehumidification tower 310 is temporarily stored in solution buffer tank 330, cooled by heat exchanger 320, and then returned to dehumidification tower 310 to cool the gas in dehumidification tower 310.

[0118] In some preferred embodiments, in order to ensure that the separated solvent can be returned to the dehumidification tower 310 for recycling, a solution circulation pump 340 is further provided on the pipeline connecting the outlet of the solution buffer tank 330 and the inlet of the heat exchanger 320 .

[0119] In some preferred embodiments, the outlet of the solution buffer tank 330 is also connected to the external liquid pipeline 20. Under the premise of ensuring that the amount of liquid required by the dehumidification tower 310 for cooling the gas is sufficient, the excess liquid in the solution buffer tank 330 can be discharged through the external liquid pipeline 20.

[0120] In some embodiments, the separation unit 400 includes at least one of a cyclone 410 , a thickener 420 , and a centrifuge 430 .

[0121] In some preferred embodiments, the separation unit 400 includes a cyclone 410, a thickener 420 and a centrifuge 430, the inlet of the cyclone 410 is connected to the brine outlet 231 of the humidifying tower 200 through a pipeline, the solid outlet of the cyclone 410 is connected to the inlet of the thickener 420, and the solid outlet of the thickener 420 is connected to the inlet of the centrifuge 430, and the cyclone 410, the thickener 420 and the centrifuge 430 are all provided with a liquid outlet, and the liquid outlets are all connected to the first raw liquid inlet 241 of the humidifying tower 200.

[0122] Therefore, the concentrated solution containing solid salt flowing out from the salt solution outlet 231 of the humidifying tower 200 enters the cyclone 410, the thickener 420 and the centrifuge 430 in sequence through the pipeline, and the concentrated solution containing solid salt is subjected to gradient solid-liquid separation, the crystallized solid salt is collected and transferred from the centrifuge 430 to the solid salt storage tank 800, and the supernatant obtained by separation is discharged from the liquid outlet of each device and returned to the first raw liquid inlet 241 of the humidifying tower 200 for crystallization separation again.

[0123] In some preferred embodiments, the cyclone 410 can be a small-cone cyclone 410 with a cone angle of 10-20°. The overflow pipe of the cyclone 410 has a diameter 0.3-0.4 times the diameter of the cyclone 410 cylinder. The centrifuge 430 can be a three-stage pusher centrifuge 430, which can reduce the solid phase moisture content of the filter cake. The thickener 420 can be configured with a discharge cone, mounted at its outlet. The centrifuge 430 is connected to the discharge cone of the thickener 420 via a pipeline.

[0124] In some preferred embodiments, the separation unit 400 further includes a liquid storage tank 450 , and the liquid outlets are connected to the liquid storage tank 450 through a pipeline, and the liquid storage tank 450 is further connected to the first raw liquid inlet 241 through a pipeline.

[0125] In some preferred embodiments, in order to ensure that the supernatant can be smoothly returned to the humidification tower 200 , a liquid delivery pump 460 is further provided on the pipeline connecting the liquid storage tank 450 and the first raw liquid inlet 241 .

[0126] In some preferred embodiments, in order to ensure that the concentrated solution containing solid salt can smoothly enter the separation unit 400, a humidification tower discharge pump 600 is provided on the pipeline connecting the cyclone 410 and the salt solution outlet 231.

[0127] In some preferred embodiments, in order to ensure the normal use of the atmospheric pressure low-temperature evaporation crystallization device 10, the atmospheric pressure low-temperature evaporation crystallization device 10 also includes a plurality of detectors (not shown in the figure, for example, can be installed on any equipment and / or pipeline of the atmospheric pressure low-temperature evaporation crystallization device 10), and the detector includes at least one of a pressure detector, a temperature detector, a flow detector and a wind speed detector.

[0128] The pressure detector can be, for example, a pressure sensor, the temperature detector can be, for example, a temperature transmitter, and the flow detector can be, for example, a flow meter in combination with a flow metering sensor for detection. Usually, the number of the above-mentioned detectors installed can be increased or decreased according to actual control and data collection needs.

[0129] In the second aspect, the present invention provides a method for separating industrial waste brine, which is suitable for a normal pressure low temperature evaporation crystallization device 10 as any of the aforementioned embodiments, including passing the raw liquid into the humidification tower 200, the raw liquid is evenly distributed through the falling film tube liquid distributor 211, and rotates into the first heat exchange channel 2121 of the falling film tube body 212 through the spiral liquid inlet channel 2112, and is heated after heat exchange with the heat medium in the second heat exchange channel in the first heat exchange channel 2121.

[0130] The heated raw liquid passes through the humidifying tower packing layer 220 and enters the evaporation crystallizer 230. The heated raw liquid crystallizes in the evaporation crystallizer 230. The crystals obtained from the crystallization and the liquid in the evaporation crystallizer 230 enter the separation unit 400 for solid-liquid separation. The liquid separated by the separation unit 400 is returned to the humidifying tower 200 for recycling.

[0131] The heated raw liquid increases the gas temperature in the evaporation crystallizer 230, thereby increasing the water content of the gas in the evaporation crystallizer 230. The gas flows from the first gas outlet 243 of the evaporation crystallizer 230 into the dehumidification tower 310 to remove moisture and then returns to the humidification tower 200 for recycling.

[0132] The raw material liquid to be processed contacts the gas in the humidification tower 200 in downstream flow.

[0133] In an optional embodiment, the method for removing moisture in the dehumidification tower 310 is to cool the gas from the evaporation crystallizer 230.

[0134] And / or, the solid-liquid separation method of the separation unit 400 includes at least one of centrifugation, sedimentation and filtration.

[0135] First embodiment This embodiment provides a normal pressure low temperature evaporation crystallization device 10, comprising the following structure: A normal-pressure low-temperature evaporation crystallization device 10 includes a raw liquid storage tank 100, a humidification tower 200, a dehumidification unit 300, and a separation unit 400.

[0136] Please refer to Figure 2 The humidifying tower 200 includes a falling film pipe portion 210, a humidifying tower packing layer 220 and an evaporation crystallizer 230, which are arranged in sequence from top to bottom and integrated into one body. The humidifying tower 200 is provided with a first raw liquid inlet 241 on the side close to the falling film pipe portion 210, that is, the upper part of the humidifying tower 200. The first raw liquid inlet 241 is connected to the raw liquid storage tank 100 through a pipeline.

[0137] Please refer to Figure 3 The falling film tube portion 210 includes a falling film tube body 212, and the falling film tube body 212 includes a first heat exchange channel 2121 and a second heat exchange channel. The first heat exchange channel 2121 and the second heat exchange channel have a wall for heat exchange. The first heat exchange channel 2121 is used to circulate the raw material liquid to be treated, and the second heat exchange channel is connected to an external heat medium source so that the raw material liquid to be treated is heated after passing through the falling film tube body 212.

[0138] In this embodiment, the external heat medium source connected to the falling film tube body 212 is a residual heat source in other process flows.

[0139] In this embodiment, the surface area of the falling film tube body 212 is 10m 2 .

[0140] In order to ensure that the raw material liquid to be processed is evenly distributed in the falling film tube and to ensure the temperature increase effect of the raw material liquid to be processed, the falling film tube portion 210 further includes a falling film tube liquid distributor 211 .

[0141] In such Figure 3 and Figure 4 In the embodiment shown, in order to ensure the installation stability of the falling film tube portion 210, the falling film tube liquid distributor 211 includes a liquid distribution tube support 2113, which is fixed to the inner wall surface of the humidification tower 200, and the thickness of the liquid distribution tube support 2113 is 16 mm.

[0142] The falling film tube liquid distributor 211 also includes a liquid distribution pipe 2111, and a spiral liquid inlet channel 2112 is provided at one end of the liquid distribution pipe 2111, and the falling film tube liquid distributor 2111 is connected to the first heat exchange channel 2121 through the spiral liquid inlet channel 2112. By setting the spiral liquid inlet channel 2112, the raw liquid to be processed enters the first heat exchange channel 2121 of the falling film tube in a spiral manner, increasing the distance the raw liquid flows in the falling film tube. At the same time, the raw liquid hits the inner wall surface of the first heat exchange channel 2121 during the spiral process in the first heat exchange channel 2121, which can also increase the turbulence degree of the raw liquid and improve the heat exchange efficiency of the raw liquid in the falling film tube.

[0143] The liquid distribution pipe 2111 is fixedly connected to the liquid distribution pipe support 2113 , and a first inlet 2115 of a spiral liquid inlet channel 2112 is opened at the connection, and the opening depth of the first inlet 2115 is 12 mm.

[0144] Among them, the liquid distribution pipe support 2113 is fixed to the inner wall surface of the humidification tower 200 by bolt connection, and the liquid distribution pipe 2111 is fixed on the liquid distribution pipe support 2113 by welding, and ensures that the first inlet 2115 of the spiral liquid inlet channel 2112 is not blocked.

[0145] The number of liquid distribution pipes 2111 is 71, and multiple liquid distribution pipes 2111 are evenly spaced on the liquid distribution pipe support 2113. The corresponding number of first heat exchange channels 2121 is also 71, and multiple liquid distribution pipes 2111 and multiple first heat exchange channels 2121 are arranged in a one-to-one correspondence.

[0146] Furthermore, in order to ensure that the raw liquid to be processed enters the falling film tube from the first inlet 2115, the falling film tube liquid distributor 211 also includes a liquid distribution tube cap 2114, and the end of the liquid distribution tube 2111 away from the spiral liquid inlet channel 2112 is sealed by the liquid distribution tube cap 2114.

[0147] In this embodiment, the spiral liquid inlet channel 2112 is located on the outer surface of the liquid distribution pipe 2111, and the inner diameter of the first heat exchange channel 2121 is larger than the outer diameter of the liquid distribution pipe 2111, so that the spiral liquid inlet channel 2112 is located inside the first heat exchange channel 2121. When the raw material liquid to be processed enters the first heat exchange channel 2121 through the first inlet 2115, most of the raw material liquid will enter the spiral liquid inlet channel 2112 along a spiral shape, and a small amount of raw material liquid will be thrown out of the spiral liquid inlet channel 2112 due to excessive centrifugal force, contact the inner wall surface of the first heat exchange channel 2121 and rebound, thereby increasing the turbulence of the raw material liquid and reducing the dynamic viscosity of the raw material liquid, which is conducive to the diffusion of solvent molecules in the raw material liquid into the gas, increasing the possibility of gas capturing solvent in the humidification tower 200, and facilitating the subsequent crystallization process.

[0148] In this embodiment, the liquid distribution pipe 2111 has a spiral liquid inlet channel 2112 with a bell mouth at one end, which increases the rotational power of the raw material liquid in the first heat exchange channel 2121 and improves the heat exchange capacity between the raw material liquid and the heat medium in the second heat exchange channel.

[0149] In this embodiment, since the raw material liquid to be processed is mostly a salt solution, in order to prevent a small amount of salt from crystallizing in the falling film tube portion 210 during the evaporation and crystallization process, thereby blocking the spiral liquid inlet channel 2112, a hydrophilic and wear-resistant coating is provided on the inner wall surface of the spiral liquid inlet channel 2112, specifically a carbon nanotube-ceramic composite coating.

[0150] In this embodiment, an ultrasonic generator 270 is provided on the outer wall of the humidification tower 200, and the ultrasonic generator 270 is provided corresponding to the falling film tube 210. The unit power of the ultrasonic generator 270 is 30 W / m 2 , total power is 200W, frequency is 20~40Hz.

[0151] In this embodiment, in order to ensure the uniform distribution of the raw liquid to be processed in the falling film pipe section 210, a humidifying tower spray head 280 is also provided in the humidifying tower 200. The humidifying tower spray head 280 is located above the falling film pipe section 210 and is connected to the first raw liquid inlet 241 through a pipeline.

[0152] The raw material liquid to be treated is heated in the falling film tube section 210, so the temperature of the gas (such as air) in the humidification tower 200 is also increased, and the water carrying capacity of the gas is improved. In addition, the structural design of the falling film tube section 210 causes the solvent in the raw material liquid to be treated to transfer to the gas, and the water content in the heated raw material liquid is reduced, which is conducive to subsequent crystallization.

[0153] The raw material liquid with a higher temperature enters the humidification tower packing layer 220. In this embodiment, the volume of the humidification tower packing layer 220 is 0.2 m 3 The inside is filled with regular corrugated packing, made of PP, with a specific surface area of 150 m 2 / m 3 .

[0154] The humidifying tower packing layer 220 is located between the falling film tube portion 210 and the evaporation crystallizer 230. By setting the humidifying tower packing layer 220, the heated raw material liquid is distributed in the humidifying tower packing layer 220, increasing the gas-liquid contact area and further improving the ability of the solvent in the raw material liquid to transfer into the gas.

[0155] The raw material liquid passing through the humidifying tower packing layer 220 enters the evaporation crystallizer 230 below it for crystallization.

[0156] The evaporation crystallizer 230 includes an evaporation zone 232, a mixing zone 233 and a crystallization zone 234 connected in sequence. The evaporation zone 232 is connected to the humidification tower packing layer 220. A crystal grower is provided in the crystallization zone 234. The opening at the bottom of the crystallization zone 234 is a salt solution outlet 231.

[0157] The raw liquid that has passed through the packing layer 220 of the humidifying tower accumulates in the evaporation crystallizer 230, and the solid solute crystals are precipitated. The precipitated crystals collide with each other and grow in the evaporation crystallizer 230, and then sink into the crystallization zone 234. Solid salts of sufficient size are screened out at the crystal grower in the crystallization zone 234, and flow out from the salt liquid outlet 231 at the bottom of the crystallization zone 234. The salt liquid outlet 231 is connected to the separation unit 400 through a pipeline. The liquid separated by the separation unit 400 is returned to the humidifying tower 200 for reuse to improve the desalination capacity of the raw liquid.

[0158] Please refer to Figure 5 In this embodiment, the outer shell of the mixing zone 233 is conical, the crystal grower is a V-shaped crystal grower 700, the edge of the V-shaped crystal grower 700 is spaced apart from the wall of the crystallization zone 234, and the crystallization zone 234 is also provided with a second raw liquid inlet 244, which is located above the V-shaped crystal grower 700, and the second raw liquid inlet 244 is connected to the raw liquid storage tank 100 through a pipeline.

[0159] In this embodiment, the diameter of the V-shaped crystal grower 700 is 1 / 3 of the diameter of the inner wall of the crystallization region 234 to ensure the crystallization effect.

[0160] By configuring the outer shell of the mixing zone 233 to be conical and in conjunction with the V-shaped crystal grower 700, crystals precipitated from the raw material liquid in the evaporation crystallizer 230 can be directed within the mixing zone 233 to the V-shaped crystal grower 700 for grain screening. The V-shaped crystal grower 700, in conjunction with the structural design of the second raw material liquid inlet 244, allows the small amount of raw material liquid entering from the second raw material liquid inlet 244 to purge the grains in the V-shaped crystal grower 700. Smaller, lighter grains are lifted by the raw material liquid and continue to collide and grow in the solution, while larger, heavier grains remain within the V-shaped crystal grower 700, waiting to be discharged to the separation unit 400 for solid-liquid separation.

[0161] In this embodiment, the V-shaped cone angle of the V-shaped crystal grower 700 is 165°. By controlling the V-shaped cone angle of the V-shaped crystal grower 700 within the above range, the growth of crystal grains is facilitated.

[0162] In this embodiment, a viewing window (not shown in the figure, for example, the viewing window can be made of transparent glass or transparent industrial plastic) is provided in the crystallization zone 234. The viewing window is located above the crystal grower. Through the viewing window, the crystal grains within the V-shaped crystal grower 700 can be observed, thereby facilitating the determination of the time when the liquid within the evaporation crystallizer 230 is discharged into the separation unit 400.

[0163] Please continue to refer to Figure 2In this embodiment, the evaporation crystallizer 230 is further provided with a clear liquid outlet 245 , which is located in the mixing zone 233 and is connected to the first raw liquid inlet 241 of the humidification tower 200 through a pipeline.

[0164] Since solid crystals will appear after the heated raw liquid enters the evaporator crystallizer 230, the solid crystals will settle downward due to gravity, that is, they will accumulate in the crystallization zone 234. The upper part of the solution in the mixing zone 233 has a low salt content. By transporting this part of the liquid with a low salt content back to the first raw liquid inlet 241 for circulation treatment, not only can the overall temperature in the humidification tower 200 be kept stable, and the temperature drop in the humidification tower 200 after a period of time can be avoided to affect the crystallization process, but the water in this part of the clear liquid can be returned to the falling film tube part 210 for heating, so that more solvent is transferred to the gas, further improving the crystallization ability of the raw liquid.

[0165] Due to the design of the falling film tube 210 in the humidifying tower 200, the overall temperature in the humidifying tower 200 is relatively high, so the water carrying capacity of the gas in the humidifying tower 200 is increased. Through the design of the ultrasonic generator 270, the falling film tube 210 and the humidifying tower packing layer 220, more solvent in the raw material liquid is transferred to the gas, and the gas in the humidifying tower 200 is hot saturated moisture.

[0166] Please refer to Figure 1 、 Figure 2 and Figure 8 A first gas outlet 243 is provided on the side of the evaporation crystallizer 230 close to the humidification tower packing layer 220, that is, the evaporation zone 232 of the evaporation crystallizer 230 is provided with the first gas outlet 243; a first gas inlet 242 is also provided on the side of the humidification tower 200 close to the falling film tube portion 210, and the dehumidification unit 300 includes a dehumidification tower 310, and the dehumidification tower 310 includes a second gas inlet 311 and a second gas outlet 312. The first gas outlet 243 and the second gas inlet 311 are connected, and the second gas outlet 312 and the first gas inlet 242 are connected, so that the humidification tower 200 and the dehumidification tower 310 are connected, thereby realizing the normal pressure gas circulation in the humidification tower 200 and the dehumidification tower 310.

[0167] The hot saturated wet gas that has absorbed the solvent in the humidifying tower 200 flows out from the first gas outlet 243 of the evaporation zone 232 and enters the dehumidifying tower 310 from the second gas inlet 311. After being processed by the dehumidifying tower 310, the moisture content in the hot saturated wet gas is reduced, and the solvent and gas in the hot saturated wet gas are separated in the dehumidifying tower 310. The gas returns to the humidifying tower 200 for recycling. The salt content in the solvent is extremely low, the conductivity is 120μs / cm, and the purity is high, which meets the external discharge standards. It can be directly discharged or connected to other processes (for example, returned to the production system of chemical materials) for reuse.

[0168] Please refer to Figure 8 In this embodiment, in order to adapt to the process of the normal pressure low temperature evaporation crystallization device 10, the second gas inlet 311 is located at the lower part of the dehumidification tower 310, and the second gas outlet 312 is located at the upper part of the dehumidification tower 310. The gas can be naturally overflowed in the dehumidification tower 310 to achieve gas circulation.

[0169] Please refer to Figure 2 At the same time, first gas outlet 243 is located in evaporation zone 232 of evaporation crystallizer 230. Therefore, it is understandable that first gas outlet 243 is located at the lower portion of humidification tower 200. To ensure effective gas-liquid contact, first gas inlet 242 is located at the top of humidification tower 200, resulting in a co-current gas-liquid contact process within humidification tower 200. The raw material liquid maintains a low concentration during evaporation, reducing material viscosity and ion supersaturation, and suppressing scaling at the source. Therefore, the positioning of first gas outlet 243 and first gas inlet 242 also contributes to the anti-scaling effect of falling film tube section 210.

[0170] In this embodiment, in order to ensure that the gas is evenly distributed in the humidification tower 200 , a gas distributor 290 is further provided in the humidification tower 200 . The gas distributor 290 is located below the first gas inlet 242 .

[0171] Please refer to Figure 6 and Figure 7 In this embodiment, in order to adjust and control the gas content in the humidification tower 200, a gas opening adjustment component is provided at the first gas outlet 243. The gas opening adjustment component is a louver-type adjustment component 250. The louver-type adjustment component 250 includes a fixing member 251. A plurality of openings are provided on the fixing member 251. An adjustment member 252 is provided on the surface of each opening. The adjustment member 252 can selectively move relative to the fixing member 251 to open or close the opening, thereby adjusting the opening degree of the opening on the fixing member 251, thereby adjusting the flow rate of gas entering the dehumidification tower 310 from the humidification tower 200.

[0172] In this embodiment, the opening can be adjusted from 0° to 90°, with the higher the degree, the wider the opening. The opening can be adjusted by an external handle, with each level adjustable by 11.25°, for a total of 8 levels. A positioning hole and positioning pin are provided to lock the open position.

[0173] The movement process of the adjusting member 252 of the louver-type adjusting assembly 250 relative to the fixing member 251 can be adjusted by the existing structure.

[0174] In this embodiment, the number of openings on the fixing member 251 is 8.

[0175] In this embodiment, the first gas outlet 243 is an annular structure on the upper part of the evaporation crystallizer 230, and the fixing member 251 and the adjusting member 252 are arranged in the first gas outlet 243. Therefore, the fixing member 251 is annular and the adjusting member 252 is fan-shaped.

[0176] Please refer to Figure 6 In this embodiment, a humidifying tower demister 260 is further provided at the first gas outlet 243. The humidifying tower demister 260 is a wire mesh demister with a thickness of 60 mm.

[0177] The humidification tower demister 260 is located below the gas opening adjustment assembly. After the gas enters the first gas outlet 243 from the evaporation zone 232, it must first pass through the humidification tower demister 260 to remove small liquid droplets entrained in the gas. This prevents salt from the small droplets from entering the dehumidification tower 310 with the gas, thereby ensuring the purity of the liquid separated in the dehumidification tower 310.

[0178] Please refer to Figure 1 In this embodiment, an induced draft fan 500 is provided on the pipeline connecting the first gas outlet 243 and the second gas inlet 311, and on the pipeline connecting the second gas outlet 312 and the first gas inlet 242, to assist in recycling the gas in the humidification tower 200 and the dehumidification tower 310, and to bring out the solvent in the humidification tower 200 for separation.

[0179] In this embodiment, the induced draft fan 500 is a high temperature and high humidity resistant mixed flow fan with an air volume of 3000m 3 / h, wind pressure 2200Pa, and the power cable is led out of the induced draft fan 500 through a stainless steel pipe connected with a threaded port.

[0180] In this embodiment, dehumidification tower 310 removes moisture from the hot, saturated wet gas by changing the gas temperature. Since higher gas temperatures increase water-carrying capacity, while lower gas temperatures decrease water-carrying capacity, lowering the temperature of the hot, saturated wet gas within dehumidification tower 310 allows the solvent in the hot, saturated wet gas to be separated from the gas. The resulting gas is cold, saturated wet gas, which has a lower water content than the hot, saturated wet gas, thus separating the solvent from the feedstock liquid.

[0181] Therefore, the dehumidification unit 300 further includes a heat exchanger 320 , and the dehumidification tower 310 is connected to the heat exchanger 320 via a pipeline to cool the gas in the dehumidification tower 310 .

[0182] Please refer to Figure 8In this embodiment, in order to ensure the cooling effect of the hot saturated moisture, a dehumidification tower packing layer 313 is provided in the dehumidification tower 310, and a dehumidification tower spray head 314 is provided above the dehumidification tower packing layer 313. The dehumidification tower spray head 314 is connected to the outlet of the heat exchanger 320 through a pipeline. The dehumidification tower 310 is also provided with a solution outlet 315, and the solution outlet 315 is connected to the inlet of the heat exchanger 320.

[0183] It can be understood that the outlet and inlet of the heat exchanger 320 are both for introducing gas, and the heat exchanger 320 should also have an inlet and outlet for heat exchange medium to achieve a cooling process for the gas.

[0184] In this embodiment, in order to reduce the water content in the hot saturated wet gas as much as possible, the number of the dehumidification tower packing layers 313 is 2, and the total volume of the two dehumidification tower packing layers 313 is 0.6m 3 The inside is filled with regular corrugated packing, made of PP, with a specific surface area of 150 m 2 / m 3 .

[0185] A dehumidification tower spray head 314 is provided above each dehumidification tower packing layer 313 , and each dehumidification tower spray head 314 is connected to the outlet of the heat exchanger 320 through a pipeline.

[0186] In this embodiment, a dehumidification tower demister 316 is further provided in the dehumidification tower 310 . The dehumidification tower demister 316 is provided above the dehumidification tower packing layer 313 so that small water droplets in the gas can be filtered out when the gas passes through the dehumidification tower demister 316 .

[0187] In this embodiment, a dehumidification tower spray head 314 is also provided above the dehumidification tower demister 316, and the dehumidification tower demister 316 is a wire mesh demister.

[0188] In this embodiment, the solution outlet 315 is located at the bottom of the dehumidification tower 310 , so that the separated solvent falls by gravity and is discharged from the solution outlet 315 .

[0189] Please refer to Figure 1 In this embodiment, to improve the heat exchange efficiency of heat exchanger 320, dehumidification unit 300 further includes a solution buffer tank 330. The inlet of solution buffer tank 330 is connected to solution outlet 315, and the outlet of solution buffer tank 330 is connected to the inlet of heat exchanger 320. The solvent separated by dehumidification tower 310 is temporarily stored in solution buffer tank 330, cooled by heat exchanger 320, and then returned to dehumidification tower 310 to cool the gas in dehumidification tower 310.

[0190] In this embodiment, in order to ensure that the separated solvent can be returned to the dehumidification tower 310 for recycling, a solution circulation pump 340 is further provided on the pipeline connecting the outlet of the solution buffer tank 330 and the inlet of the heat exchanger 320 .

[0191] In this embodiment, the outlet of the solution buffer tank 330 is also connected to the external liquid pipeline 20. Under the premise of ensuring that the amount of liquid required by the dehumidification tower 310 for cooling the gas is sufficient, the excess liquid in the solution buffer tank 330 can be discharged through the external liquid pipeline 20.

[0192] In this embodiment, the separation unit 400 includes a cyclone 410, a thickener 420 and a centrifuge 430. The inlet of the cyclone 410 is connected to the brine outlet 231 of the humidifying tower 200 through a pipeline, the solid outlet of the cyclone 410 is connected to the inlet of the thickener 420, and the solid outlet of the thickener 420 is connected to the inlet of the centrifuge 430. The cyclone 410, the thickener 420 and the centrifuge 430 are all provided with a liquid outlet, and the liquid outlets are all connected to the first raw liquid inlet 241 of the humidifying tower 200.

[0193] Therefore, the concentrated solution containing solid salt flowing out from the salt solution outlet 231 of the humidifying tower 200 enters the cyclone 410, the thickener 420 and the centrifuge 430 in sequence through the pipeline, and the concentrated solution containing solid salt is subjected to gradient solid-liquid separation, the crystallized solid salt is collected and transferred from the centrifuge 430 to the solid salt storage tank 800, and the supernatant obtained by separation is discharged from the liquid outlet of each device and returned to the first raw liquid inlet 241 of the humidifying tower 200 for crystallization separation again.

[0194] In this embodiment, the cyclone 410 uses a small cone angle cyclone 410 with a cone angle of 15°. The diameter of the overflow pipe of the cyclone 410 is 0.34 times the diameter of the cyclone 410 cylinder. The centrifuge 430 is a three-stage pusher centrifuge 430, which can reduce the solid phase moisture content of the filter cake. The thickener 420 is selected to have a discharge cone structure, and the discharge cone is installed at its discharge port. The centrifuge 430 is connected to the discharge cone of the thickener 420 via a pipeline.

[0195] In this embodiment, the separation unit 400 further includes a liquid storage tank 450 , and the liquid outlets are connected to the liquid storage tank 450 through a pipeline, and the liquid storage tank 450 is further connected to the first raw liquid inlet 241 through a pipeline.

[0196] In this embodiment, in order to ensure that the supernatant can be smoothly returned to the humidification tower 200 , a liquid delivery pump 460 is further provided on the pipeline connecting the liquid storage tank 450 and the first raw liquid inlet 241 .

[0197] In this embodiment, in order to ensure that the concentrated solution containing solid salt can smoothly enter the separation unit 400, a humidification tower discharge pump 600 is provided on the pipeline connecting the cyclone 410 and the salt solution outlet 231.

[0198] In this embodiment, in order to ensure the normal use of the atmospheric pressure low-temperature evaporation crystallization device 10, the atmospheric pressure low-temperature evaporation crystallization device 10 also includes a plurality of detectors (not shown in the figure, for example, can be installed on any equipment and / or pipeline of the atmospheric pressure low-temperature evaporation crystallization device 10), and the detector includes at least one of a pressure detector, a temperature detector, a flow detector and a wind speed detector.

[0199] Please refer to Figure 9 This embodiment also provides a method for separating industrial waste brine, which is applicable to the above-mentioned normal pressure low temperature evaporation crystallization device 10. The specific process is as follows: All electrical instrument components in the atmospheric pressure low temperature evaporation crystallization device 10 are controlled to open and close by an external control switch.

[0200] About 1 / 3 of the volume of clean water is pre-added into the solution buffer tank 330 as the cooling working fluid of the dehumidification tower 310 .

[0201] The second heat exchange channel inlet 2123 of the falling film tube body 212 is connected to the outside exhaust steam pipeline, and the second heat exchange channel outlet 2122 is connected to the outside condensate pipeline, so that the exhaust gas and other heat exchange media are cooled after heat exchange in the falling film tube body 212 and flow into the outside condensate pipeline, thereby realizing the re-absorption of the exhaust gas heat.

[0202] The inlet of the heat exchange medium of the heat exchanger 320 is connected to the outer circulating water supply pipeline, and the outlet of the heat exchange medium is connected to the outer circulating water return pipeline. The outer circulating water supply pipeline and the outer circulating water return pipeline are connected outside the boundary and the temperature is adjusted so that the heat exchange medium can be recycled.

[0203] After the above work is ready, the raw material liquid to be processed can be passed into the raw material liquid storage tank 100. When the volume of the raw material liquid to be processed in the raw material liquid storage tank 100 reaches 80%, the raw material liquid is stopped and the raw material liquid delivery pump is started at a speed of 1~2m 3 The raw material liquid to be processed is transported from the first raw material liquid inlet 241 to the humidification tower 200 at a flow rate of / h, and is evenly sprayed on the falling film tube liquid distributor 211 through the humidification tower spray head 280.

[0204] The raw liquid to be treated enters the spiral liquid inlet channel 2112 from the first inlet 2115 of the liquid distribution pipe 2111, and enters the falling film tube liquid distributor 211 in the form of a spiral flow. A small amount of fluid in the spiral liquid inlet channel 2112 is thrown onto the inner wall surface of the first heat exchange channel 2121 of the falling film tube body 212 due to the excessive centrifugal force, and is rebounded by the inner wall surface of the falling film tube body 212, and merges with the swirling raw liquid in the spiral liquid inlet channel 2112, which increases the turbulence degree of the raw liquid and reduces the dynamic viscosity of the raw liquid, which is beneficial to the diffusion of solvent molecules in the raw liquid to the gas in the humidification tower 200.

[0205] After the raw material liquid swirls within the first heat exchange channel 2121 and exchanges heat with the heat exchange medium within the second heat exchange channel, the raw material liquid heats up and flows from the first heat exchange channel 2121 to the humidification tower packing layer 220. Because the falling film tube liquid distributor 211 evenly distributes the raw material liquid, the raw material liquid is evenly spread across the humidification tower packing layer 220 as it flows from the first heat exchange channel 2121 to the humidification tower packing layer 220, flowing through the packing pores of the humidification tower packing layer 220. This increases the surface area of the raw material liquid, further facilitating the diffusion of solvent molecules into the gas within the humidification tower 200 and enhancing the evaporation effect of the raw material liquid.

[0206] The raw liquid flowing out of the humidifying tower packing layer 220 enters the evaporation crystallizer 230, and the liquid level rises from the crystallization zone 234 to the mixing zone 233 in the evaporation crystallizer 230. When the liquid level in the evaporation crystallizer 230 reaches 50% of the total liquid level height of the evaporation crystallizer 230, the delivery pump is started and the flow rate is set to 2-3m³ / h. The liquid in the upper layer of the evaporation crystallizer 230 is pumped from the clear liquid outlet 245 to the first raw liquid inlet 241 to realize the circulation treatment of the raw liquid. The temperature of the falling film tube body 212 gradually rises, which is conducive to the evaporation of the raw liquid. At the same time, the delivery flow rate of the raw liquid delivery pump is set to 0.1~0.2m³ / h.

[0207] Open the louver adjustment assembly 250 on the first gas outlet 243, adjust the opening of the opening on the fixing part 251 to 45°, and lock the position of the adjustment part 252, start the induced draft fan 500 on the gas circulation pipe of the humidifying tower 200 and the dehumidifying tower 310, set the wind speed to 1~5m / s, and realize normal pressure air circulation in the humidifying tower 200 and the dehumidifying tower 310.

[0208] When the temperature in the humidification tower 200 reaches 60° C., the ultrasonic generator 270 is started and the solution circulation pump 340 is turned on at the same time to realize solution circulation between the dehumidification tower 310 and the heat exchanger 320 .

[0209] The heat exchange process between the raw liquid and the falling film tubes within humidification tower 200 increases the gas temperature within the tower 200, dramatically increasing the thermal motion of the solvent within the tower 200. Some of the solvent diffuses from the raw liquid into the gas, forming saturated moisture. The packing layer 220 in the humidification tower increases the escape area of the solvent in the raw liquid, facilitating its diffusion and escape into the gas. The ultrasonic generator 270, in conjunction with the ultrasonic generator 270, generates tiny bubbles in the raw liquid that quickly burst. This entire process reduces the viscosity of the raw liquid, making it easier for the solvent in the raw liquid to diffuse and escape into the gas. Furthermore, the minute vibrations generated by the ultrasonic generator 270 prevent scaling of the falling film tube 210, thereby increasing the thermal efficiency of the humidification tower 200.

[0210] After the above-mentioned evaporation process, the gas in the humidification tower 200 is hot saturated moisture, which is discharged from the first gas outlet 243 of the evaporation crystallizer 230, and enters the dehumidification tower 310 under the action of the induced draft fan 500. The hot saturated moisture rises from the bottom of the dehumidification tower 310 to the top. During this period, in the dehumidification tower packing layer 313, it is in countercurrent contact with the low-temperature water sprayed from the dehumidification tower spray head 314 above the dehumidification tower packing layer 313. Based on the characteristic that the saturated humidity of air changes with temperature, while lowering the gas temperature, the solvent in the hot saturated moisture is transferred to the low-temperature water, and the water carrying capacity of the gas is reduced to obtain cold saturated moisture.

[0211] The temperature and moisture content of the hot, saturated wet gas decrease within dehumidification tower 310. After heat and mass transfer between the low-temperature water in dehumidification tower 310 and the hot, saturated wet gas, the temperature rises and enters heat exchanger 320 for cooling before returning to dehumidification tower 310 for recycling. As the evaporation process progresses, the solvent in the feedstock liquid is gradually carried into dehumidification tower 310 by the hot, saturated wet gas and remains there. Consequently, the amount of liquid in solution buffer tank 330 gradually increases. Because hot, saturated wet gas is less likely to carry solutes, the water separated within dehumidification tower 310 is of high purity. Excess liquid beyond that required for circulation within dehumidification tower 310 can be directly used for external production via external liquid pipelines.

[0212] As evaporation continues, crystals begin to appear in the V-shaped crystal grower 700 in the crystallization zone 234. At this time, the raw material liquid to be processed is introduced into the crystallization zone 234 from the second raw material liquid inlet 244, and the surface of the V-shaped crystal grower 700 is purged. After the raw material liquid flows through the V-shaped crystal grower 700, due to the reaction force, this part of the raw material liquid moves upward along the V-shaped crystal grower 700. The movement speed of the raw material liquid flow is controlled to be 2~7mm / s. When the weight of the crystal is large enough and reaches the critical point, it breaks away from the rising liquid flow in the V-shaped crystal grower 700 and falls to the bottom of the V-shaped crystal grower 700. The crystal is observed through the visual window. When the crystal reaches 1 / 3 of the visual window, the humidification tower discharge pump 600 is started and the pressure is controlled to be 0.6~1MPa. The crystals in the crystallization zone 234 are discharged. The solid slurry is delivered to cyclone 410 via a pipeline. The slurry containing crystals undergoes high-speed centrifugal motion within cyclone 410. After centrifugal separation, most of the large particles, a small portion of small particles, and a small portion of solvent enter thickener 420. The small portion of large particles, most of the small particles, and most of the solvent then enter liquid storage tank 450 via a pipeline from the upper portion of cyclone 410. When the liquid level in thickener 420 reaches 20% of its volume, thickener 420 is activated. The slurry separated in cyclone 410 is further concentrated within thickener 420. The light liquid overflows from the overflow pipe of thickener 420 into liquid storage tank 450, while the heavy liquid is discharged from thickener 420 into centrifuge 430 for centrifugal separation. The filter cake separated in centrifuge 430 enters solid salt storage tank 800, while the mother liquor enters liquid storage tank 450 via a pipeline. The solution in liquid storage tank 450 is circulated and reused in humidification tower 200.

[0213] Test Example 1 The normal pressure low temperature evaporation crystallization device 10 of the first embodiment is used to treat saline washing wastewater, i.e., raw liquid. The saline wastewater is a sodium chloride solution treated by a pilot plant at a rate of 100 kg / h, wherein the sodium chloride content is 8%±0.3%.

[0214] The gas circulation speed in the humidifying tower 200 and the dehumidifying tower 310 of the atmospheric pressure low-temperature evaporation crystallization device 10 is 2 m / s, the filler spray density is 9-12 m³ / m³, the chloride content in the solution separated by the dehumidifying tower 310 is less than 200 ppm, and the water quality is clear; the particle size D50 of the sodium chloride solid particles separated by the centrifuge 430 is 200 μm, the heat source uses the factory's secondary steam exhaust, and 95 kg of steam exhaust condensate is collected, achieving the expected design effect.

[0215] Test Example 2 The normal pressure low temperature evaporation crystallization device 10 of the first embodiment is used to treat salt-containing washing wastewater, i.e., raw liquid. The salt-containing wastewater is sodium sulfate wastewater treated by a 100 kg / h pilot plant, with a sodium sulfate content of 3.6-5%, COD: 1200-1500 ppm, and a hardness of ≤150.

[0216] The gas circulation speed in the humidifying tower 200 and the dehumidifying tower 310 of the atmospheric pressure low-temperature evaporation crystallization device 10 is 1.8 m / s, the filler spray density is 10~12 m³ / m³, the sulfate content in the solution separated by the dehumidifying tower 310 is less than 50 ppm, the COD is less than 300 ppm, and the water quality is clear; the sodium sulfate solid particles separated by the centrifuge 430 have a particle size D50=200 μm and a COD of about 18000 ppm. The heat source uses factory steam condensate (temperature ≥97°C), achieving the expected design effect.

[0217] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A normal pressure low temperature evaporation crystallization device, characterized in that: It includes raw liquid storage tank, humidification tower, dehumidification unit and separation unit; The humidification tower includes a falling film pipe portion, a humidification tower packing layer and an evaporation crystallizer which are sequentially arranged from top to bottom and integrated into one body. A first raw material liquid inlet is provided on the side of the humidification tower close to the falling film pipe portion, and the first raw material liquid inlet is connected to the raw material liquid storage tank through a pipeline; The falling film tube portion includes a falling film tube liquid distributor and a falling film tube body, the falling film tube body includes a first heat exchange channel and a second heat exchange channel, the falling film tube liquid distributor includes a liquid distribution pipe, one end of the liquid distribution pipe is provided with a spiral liquid inlet channel, and the falling film tube liquid distributor is connected to the first heat exchange channel through the spiral liquid inlet channel, and the second heat exchange channel is connected to an external heat medium source; The dehumidification unit includes a dehumidification tower, which includes a second gas inlet and a second gas outlet; the humidification tower is further provided with a first gas inlet on a side close to the falling film tube portion, and the evaporation crystallizer is provided with a first gas outlet on a side close to the packing layer of the humidification tower, the first gas outlet is connected to the second gas inlet, and the second gas outlet is connected to the first gas inlet, so that the humidification tower and the dehumidification tower are connected; A salt solution outlet is provided on a side of the evaporation crystallizer away from the first gas outlet. The salt solution outlet is connected to the separation unit through a pipeline. The liquid separated by the separation unit is returned to the humidification tower.

2. The device according to claim 1, characterized in that The evaporation crystallizer comprises an evaporation zone, a mixing zone and a crystallization zone which are connected in sequence, wherein the evaporation zone is connected to the packing layer of the humidification tower, a crystal grower is provided in the crystallization zone, and the opening at the bottom of the crystallization zone is the salt solution outlet; And / or, the outer shell of the mixing zone is conical, the crystal grower is a V-shaped crystal grower, the edge of the V-shaped crystal grower is spaced apart from the wall of the crystallization zone, the crystallization zone is further provided with a second raw material liquid inlet, the second raw material liquid inlet is located above the V-shaped crystal grower, and the second raw material liquid inlet is connected to the raw material liquid storage tank through a pipeline; And / or, the V-shaped cone angle of the V-shaped crystal grower is 120-165°; And / or, a visual window is further provided on the crystallization area, and the visual window is located above the crystal grower; And / or, the evaporation crystallizer is further provided with a clear liquid outlet, which is located between the salt solution outlet and the first gas outlet and is connected to the first raw liquid inlet of the humidification tower through a pipeline.

3. The device according to claim 1 or 2, characterized in that A gas opening adjustment component is provided at the first gas outlet, and the gas opening adjustment component includes any one of a louver adjustment component or a positioning pin; And / or, the louver-type adjustment assembly includes a fixing member, the fixing member is provided with a plurality of openings, and a surface of each opening is provided with an adjustment member, the adjustment member can selectively move relative to the fixing member to open or close the opening; and / or, the number of the openings on the fixing member is at least two; And / or, a humidifying tower demister is further provided at the first gas outlet, and the humidifying tower demister is located below the gas opening adjustment assembly; And / or, the humidifying tower demister includes any one of a wire mesh demister or a spray head.

4. The device according to claim 1, characterized in that The falling film tube liquid distributor further includes a liquid distribution pipe support and a liquid distribution pipe cap. The liquid distribution pipe support is fixed in the humidification tower. The liquid distribution pipe is fixedly connected to the liquid distribution pipe support, and a first inlet of the spiral liquid inlet channel is opened at the connection. The end of the liquid distribution pipe away from the spiral liquid inlet channel is sealed by the liquid distribution pipe cap. And / or, the inner diameter of the first heat exchange channel is larger than the outer diameter of the liquid distribution pipe, so that the spiral liquid inlet channel is located inside the first heat exchange channel; And / or, one end of the liquid distribution pipe having the spiral liquid inlet channel is a bell mouth; And / or, the inner wall surface of the spiral liquid inlet channel is provided with a hydrophilic wear-resistant coating; And / or, the hydrophilic wear-resistant coating includes any one of a carbon nanotube-ceramic composite coating and a silicon carbide coating.

5. The device according to claim 1, characterized in that The humidifying tower is also provided with an ultrasonic generator, which is arranged corresponding to the falling film tube portion; And / or, the ultrasonic generator is located on the outer surface of the humidification tower; And / or, the normal pressure low temperature evaporation crystallization device further includes a plurality of detectors, wherein the detectors include at least one of a pressure detector, a temperature detector, a flow detector and a wind speed detector.

6. The device according to claim 1, characterized in that A humidifying tower spray head is further provided in the humidifying tower, and the humidifying tower spray head is located above the falling film tube portion and is connected to the first raw material liquid inlet through a pipeline; And / or, the first gas inlet is located at the top of the humidification tower, and a gas distributor is further provided in the humidification tower, and the gas distributor is located below the first gas inlet.

7. The device according to claim 1, characterized in that The dehumidification unit further includes a heat exchanger, and the dehumidification tower is connected to the heat exchanger through a pipeline to cool the gas in the dehumidification tower; And / or, a dehumidification tower packing layer is provided in the dehumidification tower, a dehumidification tower spray head is provided above the dehumidification tower packing layer, the dehumidification tower spray head is connected to the outlet of the heat exchanger through a pipeline, and the dehumidification tower is further provided with a solution outlet, and the solution outlet is connected to the inlet of the heat exchanger; And / or, the number of the dehumidification tower packing layers is multiple, a dehumidification tower spray head is provided above each of the dehumidification tower packing layers, and each of the dehumidification tower spray heads is connected to the outlet of the heat exchanger through a pipeline; And / or, the dehumidification unit further comprises a solution buffer tank, the inlet of the solution buffer tank is communicated with the solution outlet, and the outlet of the solution buffer tank is communicated with the inlet of the heat exchanger; And / or, a solution circulation pump is further provided on the pipeline connecting the outlet of the solution buffer tank and the inlet of the heat exchanger; And / or, the outlet of the solution buffer tank is also connected to an external liquid pipeline; And / or, an induced draft fan is provided on the pipeline communicating between the first gas outlet and the second gas inlet and / or the pipeline communicating between the second gas outlet and the first gas inlet.

8. The device according to claim 1, characterized in that The separation unit includes at least one of a cyclone, a thickener, and a centrifuge; And / or, the separation unit includes a cyclone, a thickener and a centrifuge, the inlet of the cyclone is connected to the brine outlet of the humidification tower through a pipeline, the solid outlet of the cyclone is connected to the inlet of the thickener, the solid outlet of the thickener is connected to the inlet of the centrifuge, and the cyclone, the thickener and the centrifuge are all provided with a liquid outlet, and the liquid outlets are all connected to the first raw liquid inlet of the humidification tower; And / or, the separation unit further comprises a liquid storage tank, the liquid outlets are connected to the liquid storage tank via a pipeline, and the liquid storage tank is further connected to the first raw liquid inlet via a pipeline; And / or, a liquid delivery pump is further provided on the pipeline connecting the liquid storage tank and the first raw liquid inlet; And / or, a humidification tower discharge pump is provided on the pipeline connecting the cyclone and the salt solution outlet.

9. A method for separating industrial waste brine, characterized in that: Suitable for the atmospheric pressure low temperature evaporation crystallization device according to any one of claims 1 to 8, comprising: introducing the raw material liquid into the humidification tower, the raw material liquid being evenly distributed through the falling film tube liquid distributor, and rotating through the spiral liquid inlet channel into the first heat exchange channel of the falling film tube body, and exchanging heat with the heat medium in the second heat exchange channel in the first heat exchange channel and then heating up; The heated raw liquid passes through the packing layer of the humidifying tower and enters the evaporation crystallizer. The heated raw liquid crystallizes in the evaporation crystallizer. The crystals obtained from the crystallization and the liquid in the evaporation crystallizer enter the separation unit for solid-liquid separation. The liquid separated by the separation unit is returned to the humidifying tower for recycling. The heated raw liquid increases the gas temperature in the evaporation crystallizer, thereby increasing the water content of the gas in the evaporation crystallizer. The gas flows from the first gas outlet of the evaporation crystallizer into the dehumidification tower to remove moisture, and then returns to the humidification tower for recycling. The raw material liquid contacts with the gas in the humidification tower in a downstream manner.

10. The method according to claim 9, characterized in that The method for removing moisture in the dehumidification tower is to cool the gas from the evaporation crystallizer; And / or, the solid-liquid separation method of the separation unit includes at least one of centrifugation, sedimentation and filtration.

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