MVR (Mechanical Vapor Recompression) evaporating crystallizer suitable for high-salt-content wastewater and use method

Abstract

The invention discloses an MVR (Mechanical Vapor Recompression) evaporation crystallizer suitable for high-salt-content wastewater and a use method, and belongs to the field of evaporation crystallizers, the MVR evaporation crystallizer comprises a falling film evaporation part, a circulating pump, a separation part and a compressor; the liquid discharge end of the falling film evaporation part is connected with the input end of the circulating pump through a backflow pipeline, and the output end of the circulating pump is connected with the liquid inlet end of the falling film evaporation part through a liquid feeding pipeline; the falling film evaporation part is communicated with the separation part through a ventilation pipeline and a flow guide pipeline, the exhaust end of the separation part is connected with the input end of the cyclone separator, and the exhaust end of the cyclone separator is connected with the input end of the compressor; according to the invention, a coarse-to-fine three-stage separation scheme is constructed, and liquid drops with different physical characteristics can be captured; the liquid carrying amount of secondary steam can be greatly reduced, and core equipment is directly protected; the invention provides higher safety margin and operation flexibility for the condition that the wastewater composition is complex or the treatment capacity has certain fluctuation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of evaporation crystallizers, more particularly to an MVR evaporation crystallizer suitable for high-salt wastewater and a use method thereof. BACKGROUND

[0002] In industrial production, treating wastewater is an important measure for environmental protection, and the MVR evaporation crystallizer is a device commonly used for wastewater treatment. It greatly reduces the consumption of external steam by reusing the energy of secondary steam generated in the evaporation process. It is applied to industries that need to treat a large amount of liquid or recover solutes, and is widely used in the environmental protection industry for high-salt wastewater treatment.

[0003] In the MVR system, the compressor is the heart of the MVR, but its operating environment is extremely harsh. If the demister of the separator is not well designed, or the operating load is too high, tiny liquid droplets (containing salt) will be carried into the secondary steam. When these salt-containing liquid droplets enter the high-speed rotating compressor blades, the water evaporates and the salt is deposited on the blades. This can cause the rotor to be out of balance, causing strong vibration, and in severe cases, even the blades can be broken or the bearings can be burned out. SUMMARY

[0004] In view of the problems in the prior art, the purpose of the present application is to provide an MVR evaporation crystallizer suitable for high-salt wastewater and a use method thereof.

[0005] To solve the above problems, the technical scheme adopted by the present application is as follows.

[0006] An MVR evaporation crystallizer suitable for high-salt wastewater, comprising a falling film evaporation part, a circulating pump, a separation part and a compressor. The liquid discharge end of the falling film evaporation part is connected to the input end of the circulating pump through a reflux pipeline, and the output end of the circulating pump is connected to the liquid inlet end of the falling film evaporation part through a liquid feeding pipeline. The falling film evaporation part is connected to the separation part through an air supply pipeline and a flow guide pipeline, the exhaust end of the separation part is connected to the input end of the cyclone separator, the exhaust end of the cyclone separator is connected to the input end of the compressor, and the output end of the compressor is connected to the air inlet end of the falling film evaporation part. The separation part comprises a shell one, a baffle demisting part and a wire mesh demisting part fixed on the inner wall of the shell one, and the wire mesh demisting part is located above the baffle demisting part. The baffle demisting part comprises a hollow ring body fixed on the inner wall of the shell one and a plurality of baffle plates fixed on the inner wall of the hollow ring body.

[0007] Furthermore, multiple pipes are fixed to the inner wall of the hollow ring, and the pipes are located between the bends of two adjacent baffles. Multiple nozzles are fixed to the outside of each of the multiple pipes. A liquid inlet is fixed to the lower end of the hollow ring. A flow channel and a flow channel are opened inside the hollow ring. The flow channel is connected to the multiple pipes, and the input end of the flow channel is connected to the liquid inlet.

[0008] Furthermore, the outer surface of the plurality of baffles is provided with a drain port 1, and the interior of the plurality of baffles is provided with a flow channel 3. The flow channel 3 inside the baffles is connected to the flow channel 2 inside the hollow ring body. The lower end of the hollow ring body is fixedly connected to a drain part, and the output end of the flow channel 2 is connected to the drain part.

[0009] Furthermore, a reserved opening is provided on the outer surface of the first shell, and a second drain outlet is provided at the lower end of the first shell.

[0010] Furthermore, the inner wall of the housing is also connected to a flow equalization section, and the flow equalization section includes a plate fixed to the inner wall of the housing and a plurality of through holes opened inside the plate.

[0011] Furthermore, the upper end of the plate is integrally formed with multiple hollow annular flanges, and the inner wall of the hollow annular flanges is provided with an annular liquid distribution groove. The upper end of the hollow annular flange is fixedly connected with a liquid inlet part two, and the interior of the hollow annular flange is provided with a flow channel four that communicates with the liquid inlet part two and the annular liquid distribution groove.

[0012] Furthermore, it also includes an axial cyclone demister that connects the exhaust end of the cyclone separator to the input end of the compressor. The axial cyclone demister includes a housing two connected to the exhaust end of the cyclone separator and the input end of the compressor at both ends, a hollow cyclone ring fixed inside the housing two, an inlet end and a diffuser end opened inside the hollow cyclone ring, a throat opened inside the hollow cyclone ring that connects the inlet end and the diffuser end, cyclone blades fixed to the inner wall of the throat, multiple liquid collection cavities opened on the inner wall of the throat, a liquid baffle integrally formed on the inner wall of the throat, a liquid collection tank opened inside the hollow cyclone ring and connected to the multiple liquid collection cavities, an anti-vortex baffle fixed to the inner wall of the liquid collection tank, and an exhaust pipe and a drain pipe with one end penetrating through the housing two into the hollow cyclone ring and connected to the liquid collection tank.

[0013] Furthermore, a flow flange is fixedly connected to the inner wall of the second housing, and the flow flange is located below the hollow vortex ring; a liquid supply pipeline is fixedly connected inside the second housing, and a nozzle is fixedly connected to one end of the liquid supply pipeline that extends into the second housing, while the other end of the liquid supply pipeline passes through the second housing and extends outward.

[0014] Furthermore, the falling film evaporator is provided with an exhaust port and a condensate outlet on its exterior, a drain outlet is provided on the return pipeline, and a raw water inlet is provided on the liquid delivery pipeline.

[0015] A method for using an MVR evaporator crystallizer suitable for high-salinity wastewater includes the following steps: Step 1: Wastewater enters the liquid delivery pipeline from the raw water inlet. The circulating pump sends the wastewater into the falling film evaporator through the liquid delivery pipeline. Steam enters the falling film evaporator and exchanges heat with the wastewater, heating the wastewater and generating steam. The generated steam enters the shell through the venting pipeline. Step 2: Steam enters the first shell and first contacts the plate, then passes through the through hole to reach the baffle demister, passes between multiple baffles and reaches the wire mesh demister, and after passing through the wire mesh demister, it is discharged from the first shell and enters the cyclone separator for gas-liquid separation. Step 3: The separated steam enters the second shell. When the steam passes through the throat, it is guided by the swirl vanes and generates a swirling flow in the throat. The swirling flow causes the liquid droplets in the gas to form a liquid film on the inner wall of the throat and flow. The liquid weir forces the liquid film to detach from the mainstream of the wall and enter the liquid collection tank. The gas discharged from the hollow swirl ring is rectified by the horizontal flow flange and enters the compressor axially. Step 4: The compressor compresses the steam and then feeds it into the falling film evaporator to treat the wastewater by heat exchange and evaporation.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This scheme is equipped with a baffle demister, a wire mesh demister, and a cyclone separator. The baffle demister changes the airflow direction and uses inertia to cause larger droplets to collide with the plate wall and collect and flow down, thus removing most of the obvious liquid carried by boiling and splashing, reducing the load on the subsequent wire mesh. Then, the tiny droplets are captured and aggregated by the wire mesh demister through inertial collision, direct interception and Brownian diffusion, and finally fall off and separate. Before the steam leaves the separation chamber, most of the liquid water has been removed, and the steam dryness is greatly improved. Finally, the cyclone separator is used to perform terminal separation of the remaining droplets with a density greater than that of the steam. A three-stage separation scheme from coarse to fine is constructed, which can capture droplets with different physical properties. It can greatly reduce the liquid carried by the secondary steam and directly protect the core equipment. For cases where the wastewater composition is complex or the treatment volume fluctuates, this application provides a higher safety margin and operational flexibility.

[0017] (2) This scheme is equipped with a drain port and a nozzle. When the processing capacity of the equipment is small, the nozzle continuously sprays water to form a continuous downward flowing liquid film on the surface of the baffle plate. When the salt droplets hit this liquid film, they will be dissolved or washed away immediately, avoiding the deposition and caking of salt on the baffle plate. The salt is discharged through the drain port along with the flushing water. This gives the baffle demisting section a preliminary online self-cleaning capability, which can extend the operating cycle of the equipment. At the same time, the spray water has a certain cooling effect on the baffle plate, which can avoid the local overheating caused by the long-term contact of the baffle plate with high-temperature steam, which is conducive to the long-term stability of the equipment materials.

[0018] (3) This scheme is equipped with a flow equalization section, which can rectify the steam through multiple through holes. The steam is forced through these through holes to form a fine steam column with a more uniform velocity distribution; it creates ideal air intake conditions for the baffle plate and improves its separation efficiency; at the same time, the liquid discharged from the annular liquid distribution tank can form a downward flowing liquid film along the inner wall of the through hole. When the steam carrying salt droplets passes through the channel, the droplets hit the wet hole wall under the action of inertia, are captured, dissolved and carried away by the liquid film; it can remove some of the salt-containing droplets and significantly reduce the pollutant load in the subsequent baffle plate area; after the pre-washing of the flow equalization plate, the liquid content and salt content of the steam reaching the baffle plate have been greatly reduced, which reduces the separation pressure and scaling risk of the baffle plate.

[0019] (4) This scheme is equipped with an axial swirl demisting section. It uses the pressure difference of the compressor suction section to accelerate the steam at the throat and force the high-speed axial flow to be converted into a strong rotational flow through the swirl blades, so as to efficiently convert the kinetic energy of the steam into rotational energy. The strong centrifugal force generated by the rotation throws the residual micro-droplets and particles in the steam toward the throat wall and forms a downward spiral liquid film. The liquid film is forced to detach from the mainstream of the wall and enter the collection tank through the liquid weir. The mist droplets that still escape after the previous multi-stage separation are captured. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention. Figure One ; Figure 2 This is a schematic diagram of the overall structure of the present invention. Figure Two ; Figure 3 This is a cross-sectional view of the separation section of the present invention; Figure 4 This is a schematic diagram of the deflector and demister structure of the present invention; Figure 5 For the present invention Figure 3 Enlarged schematic diagram of the structure at point A in the middle; Figure 6 This is a schematic diagram of the liquid inlet section of the present invention; Figure 7This is a schematic diagram of the flow equalization section structure of the present invention; Figure 8 For the present invention Figure 3 Enlarged schematic diagram of the structure at point B; Figure 9 This is a three-dimensional structural diagram of the axial swirl demisting section of the present invention; Figure 10 This is a cross-sectional view of the axial swirl demisting section of the present invention; Figure 11 This is a cross-sectional view of the hollow swirl ring of the present invention.

[0021] Explanation of the labels in the diagram: 1. Falling film evaporator; 11. Return pipeline; 12. Vent pipeline; 13. Guide pipeline; 14. Drain outlet; 15. Exhaust outlet; 16. Condensate outlet; 2. Circulating pump; 21. Liquid delivery pipeline; 22. Raw water inlet; 3. Separation section; 31. Shell 1; 32. Reserved port; 33. Baffle demister section; 331. Hollow ring; 332. Baffle plate; 333. Pipeline; 334. Liquid inlet 1; 335. Liquid outlet 1; 336. Nozzle 1; 337. Liquid discharge section; 34. Wire mesh demister section; 35. Liquid outlet 2; 36. Flow equalization section; 3 61. Plate; 362. Through hole; 363. Hollow annular flange; 364. Liquid inlet section two; 365. Annular liquid distribution groove; 4. Cyclone separator; 5. Compressor; 6. Axial cyclone demister; 61. Shell two; 62. Hollow cyclone ring; 621. Inlet end; 622. Throat; 623. Diffusion end; 624. Cyclone blade; 625. Liquid collection chamber; 626. Liquid baffle; 627. Liquid collection groove; 628. Exhaust pipe; 629. Liquid discharge pipe; 630. Anti-vortex baffle; 63. Horizontal flow flange; 64. Liquid supply pipe; 65. Nozzle two. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] Please see Figures 1 to 11 An MVR evaporator crystallizer suitable for high-salinity wastewater includes a falling film evaporation section 1, a circulating pump 2, a separation section 3, and a compressor 5; The discharge end of the falling film evaporator 1 is connected to the input end of the circulation pump 2 via the return pipe 11, and the output end of the circulation pump 2 is connected to the inlet end of the falling film evaporator 1 via the liquid delivery pipe 21. The falling film evaporator 1 is connected to the separation section 3 via the ventilation pipe 12 and the guide pipe 13. The exhaust end of the separation section 3 is connected to the input end of the cyclone separator 4, the exhaust end of the cyclone separator 4 is connected to the input end of the compressor 5, and the output end of the compressor 5 is connected to the air inlet end of the falling film evaporator 1. The separation section 3 includes a housing 31, a baffle demister 33 fixed to the inner wall of the housing 31, and a wire mesh demister 34. The wire mesh demister 34 is located above the baffle demister 33. The baffle demister 33 includes a hollow ring 331 fixed to the inner wall of the housing 31 and a plurality of baffle plates 332 fixed to the inner wall of the hollow ring 331.

[0024] The falling film evaporation section 1 has an exhaust port 15 and a condensate outlet 16 on its exterior, the return pipe 11 has a drain outlet 14, and the liquid delivery pipe 21 has a raw water inlet 22.

[0025] By adopting the above technical solution, wastewater enters the liquid delivery pipeline 21 from the raw water inlet 22. The circulation pump 2 sends the wastewater into the falling film evaporator 1 through the liquid delivery pipeline 21. Steam enters the falling film evaporator 1 and exchanges heat with the wastewater, heating the wastewater and generating steam. The steam generated during the heat exchange process will reach the bottom of the falling film evaporator 1 along with the wastewater, and the steam will enter the housing 31 through the vent pipe 12. The concentrated wastewater in the falling film evaporator 1 returns to the circulation pump 2 through the return pipeline 11 for continued circulation treatment. At the same time, the wastewater is drained. Port 14 can discharge concentrated wastewater; non-condensable gases inside the falling film evaporator 1 can be discharged from exhaust port 15, and condensate outside the heat exchange pipes inside the falling film evaporator 1 can be discharged from condensate outlet 16; the falling film evaporator 1 is a mature existing technology, and its principle and structure will not be described in detail here; steam enters the shell 31, rises and passes between multiple baffles 332, changes the airflow direction through the baffles 332, and uses inertia to cause larger droplets to hit the plate wall and collect and flow down, thus treating most of the obvious wastewater generated by boiling and splashing. The steam carries liquid, reducing the load on the subsequent wire mesh. After passing through the baffle 332, the steam reaches the wire mesh demister 34. Tiny droplets are captured and coalesced by the wire mesh demister 34 through mechanisms such as inertial collision, direct interception, and Brownian diffusion, and finally drip off and separate. Before the steam leaves the separation chamber, most of the liquid water has been removed, and the steam dryness is greatly improved. The wire mesh demister 34 is usually called a wire mesh demister or wire mesh mist catcher, which is a mature existing technology and will not be described in detail here. The steam after passing through the wire mesh demister 34 is discharged from the shell 31 and enters the cyclone separator. In device 4, gas-liquid separation is carried out. The residual liquid droplets with a density greater than that of steam are separated by the cyclone separator 4. A three-stage separation scheme from coarse to fine is constructed, which can capture droplets with different physical properties. It can greatly reduce the liquid carrying amount of secondary steam and directly protect the core equipment. For cases where the wastewater composition is complex or the treatment volume fluctuates, this application provides a higher safety margin and operational flexibility. The separated steam enters the compressor 5, which compresses the steam and then inputs it into the falling film evaporator 1 to perform heat exchange evaporation treatment on the wastewater.

[0026] like Figures 4-6 As shown, multiple pipes 333 are fixed to the inner wall of the hollow ring 331, and the pipes 333 are located between the bends of two adjacent baffles 332. Multiple nozzles 336 are fixed to the outside of each of the multiple pipes 333. A liquid inlet 334 is fixed to the lower end of the hollow ring 331. A flow channel 1 and a flow channel 2 are opened inside the hollow ring 331. The flow channel 1 is connected to the multiple pipes 333, and the input end of the flow channel 1 is connected to the liquid inlet 334.

[0027] The outer surface of the plurality of baffles 332 is provided with a drain port 335, and the interior of the plurality of baffles 332 is provided with a flow channel 3 connected to the drain port 335. The flow channel 3 inside the baffles 332 is connected to the flow channel 2 inside the hollow ring 331. The lower end of the hollow ring 331 is fixedly connected to a drain part 337, and the output end of the flow channel 2 is connected to the drain part 337.

[0028] The outer surface of the housing 31 is provided with a reserved opening 32, and the lower end of the housing 31 is provided with a drain outlet 35.

[0029] By adopting the above technical solution, two main pipe interfaces can be installed in the reserved port 32. The two main pipe interfaces are connected to the second drain port 35 and the first inlet 334 respectively through two branch pipes. One main pipe interface is used to discharge the liquid discharged from the drain port 337, and the other main pipe interface is used to supply liquid into the first inlet 334. The two main pipe interfaces are sealed with the reserved port 32. The main pipe interfaces are equivalent to a manifold or branching component and are a common technology for liquid transportation. Neither of the two main pipe interfaces is shown in the accompanying drawings of this application. In this application, the improvement is not how to design the infusion pipeline, but to avoid salt deposition in the baffle area of ​​the baffle plate 332. Therefore, the design of the supply or drainage pipeline will not be described in detail here. The liquid in the first inlet 334 enters the pipeline through the first flow channel. The water flows through nozzle 333 and exits from nozzle 336. Continuous spraying through nozzle 336 forms a downward-flowing, continuous liquid film on the surface of the bend in the baffle plate 332. When salt droplets in the steam collide with this liquid film, they are immediately dissolved or washed away, preventing salt deposition and caking on the baffle plate 332. The salt flows along the outer surface of the baffle plate 332 with the rinsing water and enters drain port 335. The rinsing water in drain port 335 passes through flow channels 2 and 3 and enters drain section 337, from which it is discharged. This gives the baffle demister section 33 a preliminary online self-cleaning capability, extending the equipment's operating cycle. Simultaneously, the sprayed water has a cooling effect on the baffle plate 332, preventing localized overheating caused by prolonged contact with high-temperature steam, which is beneficial for the long-term stable use of the equipment materials.

[0030] like Figure 3 , Figure 7 and Figure 8 As shown, the inner wall of the housing 31 is also connected to a flow equalization section 36, and the flow equalization section 36 includes a plate 361 fixed to the inner wall of the housing 31 and a plurality of through holes 362 opened inside the plate 361.

[0031] The upper end of the plate 361 is integrally formed with multiple hollow annular flanges 363, and the inner wall of the hollow annular flanges 363 is provided with annular liquid distribution grooves 365. The upper end of the hollow annular flanges 363 is fixedly connected with a liquid inlet part 364, and the hollow annular flanges 363 are provided with a flow channel 4 that communicates with the liquid inlet part 364 and the annular liquid distribution grooves 365.

[0032] By adopting the above technical solution, the steam enters the shell 31 and rises to contact the plate 361. The steam can be rectified through multiple through holes 362, and the steam is forced through these through holes 362 to form a fine steam column with a more uniform velocity distribution. This creates ideal air intake conditions for the baffle plate 332 and improves its separation efficiency. The liquid inlet 364 is also connected to the pipeline of the above-mentioned pipeline interface. The flushing water enters the flow channel 4 and is discharged from the annular liquid distribution tank 365. The discharged liquid can form a downward flowing liquid film along the inner wall of the through hole 362. When the steam carrying salt droplets passes through the channel, the droplets hit the wet hole wall under the action of inertia, are captured, dissolved and carried away by the liquid film. This can remove some of the salt-containing droplets and significantly reduce the pollutant load in the subsequent baffle plate 332 area. After the pre-washing by the flow equalization plate, the liquid content and salt content of the steam reaching the baffle plate 332 have been greatly reduced, which reduces the separation pressure and scaling risk of the baffle plate 332.

[0033] like Figure 4 and Figure 6 As shown, it also includes an axial cyclone demister 6 that connects the exhaust end of the cyclone separator 4 to the input end of the compressor 5. The axial cyclone demister 6 includes a housing 61 with its two ends connected to the exhaust end of the cyclone separator 4 and the input end of the compressor 5, respectively; a hollow cyclone ring 62 fixed inside the housing 61; an inlet end 621 and a diffuser end 623 formed inside the hollow cyclone ring 62; and a throat 622 formed inside the hollow cyclone ring 62 that connects the inlet end 621 and the diffuser end 623. The following components are included: a swirl vane 624 fixed to the inner wall of the throat 622; multiple liquid collection chambers 625 formed on the inner wall of the throat 622; a liquid-blocking weir 626 integrally formed on the inner wall of the throat 622; a liquid collection trough 627 formed in the hollow swirl ring 62 and connected to the multiple liquid collection chambers 625; an anti-vortex baffle 630 fixed to the inner wall of the liquid collection trough 627; an exhaust pipe 628 and a drain pipe 629, one end of which penetrates the shell 61 and enters the hollow swirl ring 62 and is connected to the liquid collection trough 627.

[0034] The inner wall of the second housing 61 is also fixedly connected to a flow flange 63, and the flow flange 63 is located below the hollow vortex ring 62; a liquid supply pipe 64 is fixedly connected inside the second housing 61, and a nozzle 65 is fixedly connected to one end of the liquid supply pipe 64 that extends into the second housing 61, and the other end of the liquid supply pipe 64 passes through the second housing 61 and extends outward.

[0035] By adopting the above technical solution, after the steam is discharged, it enters the compressor 5 through the casing 61. When the steam passes through the hollow swirl ring 62, the pressure difference of the suction section of the compressor 5 is used to accelerate the steam at the throat 622. The swirl blades 624 force the high-speed axial flow into a strong rotational flow, efficiently converting the kinetic energy of the steam into rotational energy. The strong centrifugal force generated by the rotation throws the residual micro-droplets and particles in the steam toward the wall of the throat 622, forming a downward spiral liquid film. The liquid film is forced to detach from the mainstream of the wall at this point by the liquid-blocking weir 626 and enter the liquid collection tank 627. The mist-like droplets that still escape after the previous multi-stage separation are captured. The anti-vortex baffle 630 can prevent the generation of vortices in the liquid collection tank 627, which would cause the liquid inside to return from the liquid collection tank 627. The gas in the collection tank 627 can be discharged through the exhaust pipe 628, and the liquid in the collection tank 627 can be discharged through the drain pipe 629. When the gas passes through the hollow vortex ring 62 and reaches the horizontal flow flange 63, the horizontal flow flange 63 suppresses the tangential rotation of the internal airflow, rectifying the gas discharged from the hollow vortex ring 62 so that it enters the compressor 5 axially. At the same time, the liquid supply pipe 64 can supply condensate to the nozzle 65 and spray it out. The spraying of extremely fine droplets can keep a thin liquid film on the surface of the compressor 5 blades. In this way, even if a small amount of salt mist enters, it will be diluted by the liquid film and thrown out by centrifugal force, and will not be heated and dried on the blades to form hard scale. The liquid supply pipe 64 and the nozzle 65 can be installed and selected according to the system requirements.

[0036] How to use: Step 1: Wastewater enters the liquid delivery pipeline 21 from the raw water inlet 22. The circulation pump 2 sends the wastewater into the falling film evaporator 1 through the liquid delivery pipeline 21. Steam enters the falling film evaporator 1 and exchanges heat with the wastewater to heat the wastewater and generate steam. The generated steam enters the shell 31 through the venting pipeline 12. Step 2: Steam enters the housing 31 and first contacts the plate 361, then passes through the through hole 362 to reach the baffle demister 33, passes between multiple baffles 332 and reaches the wire mesh demister 34, and after passing through the wire mesh demister 34, it is discharged from the housing 31 and enters the cyclone separator 4 for gas-liquid separation. Step 3: The separated steam enters the casing 61. When the steam passes through the throat 622, it is guided by the swirl vanes 624 and generates a swirling flow in the throat 622. The swirling flow causes the liquid droplets in the gas to form a liquid film on the inner wall of the throat 622 and flow. The liquid-blocking weir 626 forces the liquid film to detach from the mainstream of the wall and enter the liquid collection tank 627. The gas discharged from the hollow swirl ring 62 is rectified by the horizontal flow flange 63 so that it enters the compressor 5 axially. Step 4: The compressor 5 compresses the steam and then inputs it into the falling film evaporator 1 to perform heat exchange and evaporation treatment on the wastewater.

[0037] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. An MVR evaporator crystallizer suitable for high-salinity wastewater, comprising a falling film evaporation section (1), a circulating pump (2), a separation section (3), and a compressor (5), characterized in that: The discharge end of the falling film evaporator (1) is connected to the input end of the circulation pump (2) through the return pipe (11), and the output end of the circulation pump (2) is connected to the inlet end of the falling film evaporator (1) through the liquid delivery pipe (21); the falling film evaporator (1) is connected to the separation section (3) through the ventilation pipe (12) and the guide pipe (13), the exhaust end of the separation section (3) is connected to the input end of the cyclone separator (4), the exhaust end of the cyclone separator (4) is connected to the input end of the compressor (5), and the output end of the compressor (5) is connected to the air inlet end of the falling film evaporator (1); The separation section (3) includes a housing (31), a baffle demister (33) and a wire mesh demister (34) fixed on the inner wall of the housing (31), the wire mesh demister (34) being located above the baffle demister (33); the baffle demister (33) includes a hollow ring (331) fixed on the inner wall of the housing (31) and a plurality of baffle plates (332) fixed on the inner wall of the hollow ring (331).

2. The MVR evaporator crystallizer suitable for high-salinity wastewater according to claim 1, characterized in that: The hollow ring (331) has multiple pipes (333) fixed to its inner wall, and the pipes (333) are located between the bends of two adjacent baffles (332). Multiple nozzles (336) are fixed to the outside of the multiple pipes (333). The lower end of the hollow ring (331) has a liquid inlet (334) fixed to it. The hollow ring (331) has a flow channel and a flow channel, and the flow channel is connected to the multiple pipes (333). The input end of the flow channel is connected to the liquid inlet (334).

3. The MVR evaporator crystallizer suitable for high-salinity wastewater according to claim 2, characterized in that: The outer surface of the plurality of baffles (332) is provided with a drain port (335), and the interior of the plurality of baffles (332) is provided with a flow channel (3). The flow channel (3) inside the baffles (332) is connected to the flow channel (2) inside the hollow ring (331). The lower end of the hollow ring (331) is fixedly connected to a drain section (337), and the output end of the flow channel (2) is connected to the drain section (337).

4. The MVR evaporator crystallizer suitable for high-salinity wastewater according to claim 3, characterized in that: The outer surface of the first shell (31) is provided with a reserved opening (32), and the lower end of the first shell (31) is provided with a drain outlet (35).

5. The MVR evaporator crystallizer suitable for high-salinity wastewater according to claim 4, characterized in that: The inner wall of the housing (31) is also connected to a flow equalization section (36), and the flow equalization section (36) includes a plate (361) fixed to the inner wall of the housing (31) and a plurality of through holes (362) opened inside the plate (361).

6. The MVR evaporator crystallizer suitable for high-salinity wastewater according to claim 5, characterized in that: The upper end of the plate (361) is integrally formed with multiple hollow annular flanges (363), and the inner wall of the hollow annular flanges (363) is provided with an annular liquid distribution groove (365). The upper end of the hollow annular flanges (363) is fixedly connected with a liquid inlet part two (364), and the hollow annular flanges (363) are provided with a flow channel four that communicates with the liquid inlet part two (364) and the annular liquid distribution groove (365).

7. The MVR evaporator crystallizer suitable for high-salinity wastewater according to claim 6, characterized in that: It also includes an axial cyclone demister (6) that connects the exhaust end of the cyclone separator (4) to the input end of the compressor (5), and the axial cyclone demister (6) includes a housing two (61) whose two ends are respectively connected to the exhaust end of the cyclone separator (4) and the input end of the compressor (5), a hollow cyclone ring (62) fixed inside the housing two (61), an inlet end (621) and a diffuser end (623) opened inside the hollow cyclone ring (62), and a throat (622) opened inside the hollow cyclone ring (62) that connects the inlet end (621) and the diffuser end (623). Swirl blades (624) attached to the inner wall of the throat (622), multiple liquid collection chambers (625) opened on the inner wall of the throat (622), a liquid-blocking weir (626) integrally formed on the inner wall of the throat (622), a liquid collection trough (627) opened in the hollow swirling ring (62) and connected to the multiple liquid collection chambers (625), an anti-vortex baffle (630) fixed to the inner wall of the liquid collection trough (627), an exhaust pipe (628) and a drain pipe (629) that penetrate the second shell (61) into the hollow swirling ring (62) and are connected to the liquid collection trough (627).

8. The MVR evaporator crystallizer suitable for high-salinity wastewater according to claim 7, characterized in that: The inner wall of the second housing (61) is also fixedly connected to a flow flange (63), and the flow flange (63) is located below the hollow vortex ring (62); a liquid supply pipe (64) is fixedly connected inside the second housing (61), and a nozzle (65) is fixedly connected to one end of the liquid supply pipe (64) that extends into the second housing (61), and the other end of the liquid supply pipe (64) passes through the second housing (61) and extends outward.

9. The MVR evaporator crystallizer suitable for high-salinity wastewater according to claim 8, characterized in that: The falling film evaporation section (1) is provided with an exhaust port (15) and a condensate outlet (16) on the outside. The return pipe (11) is provided with a drain outlet (14), and the liquid delivery pipe (21) is provided with a raw water inlet (22).

10. A method of using an MVR evaporator crystallizer suitable for high-salinity wastewater, characterized in that: The MVR evaporator crystallizer for high-salinity wastewater as described in claim 9 comprises the following steps: Step 1: Wastewater enters the liquid delivery pipeline (21) from the raw water inlet (22). The circulating pump (2) sends the wastewater into the falling film evaporator (1) through the liquid delivery pipeline (21). Steam enters the falling film evaporator (1) and exchanges heat with the wastewater to heat the wastewater and generate steam. The generated steam enters the shell (31) through the ventilation pipeline (12). Step 2: Steam enters the first shell (31) and first contacts the plate (361), and passes through the through hole (362) to reach the baffle demister (33). It passes through the multiple baffles (332) and reaches the wire mesh demister (34). After passing through the wire mesh demister (34), it is discharged from the first shell (31) and enters the cyclone separator (4) for gas-liquid separation. Step 3: The separated steam enters the second shell (61). When the steam passes through the throat (622), it is guided by the swirl vanes (624) and generates a swirling flow in the throat (622). The swirling flow causes the liquid droplets in the gas to form a liquid film on the inner wall of the throat (622) and flow. The liquid-blocking weir (626) forces the liquid film to detach from the main flow on the wall and enter the liquid collection tank (627). The gas discharged from the hollow swirl ring (62) is rectified by the horizontal flow flange (63) so that it enters the compressor (5) axially. Step 4: The compressor (5) compresses the steam and then inputs it into the falling film evaporator (1) to perform heat exchange and evaporation treatment on the wastewater.

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