Hydrocyclone separation type forced circulation MVR (Mechanical Vapor Recompression) crystallization evaporator

Abstract

The utility model relates to the technical field of evaporators, in particular to a hydrocyclone separation type forced circulation MVR (Mechanical Vapor Recompression) crystallization evaporator which comprises a feeding pipeline for conveying mother liquor; the gravity settling tank is communicated with the feeding pipeline and can receive mother liquor; the heater is communicated with the gravity settling tank; the forced circulation pump is respectively communicated with the gravity settling tank and the heater and is used for conveying the mother liquor in the gravity settling tank into the heater; the evaporator is communicated with the heater and can receive the mother liquor conveyed by the heater; the cyclone hydraulic separator is mounted in the evaporator and can be used for crystallizing and separating the crystallization liquid, and the cyclone hydraulic separator is communicated with the gravity settling tank and can be used for conveying separated clear liquid into the gravity settling tank; and the steam compressor is respectively communicated with the heater and the evaporator, and can pressurize and heat the steam formed by evaporation in the evaporator and convey the steam into the heater. Blockage of the heater and the forced circulation pump can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of evaporators, and in particular to a hydrocyclone separation type forced circulation MVR crystallization evaporator. Background Art

[0002] MVR refers to mechanical vapor recompression technology. The principle of MVR evaporator is to use a steam compressor to compress the secondary steam generated by the evaporation of the material itself, convert electrical energy into thermal energy, increase the energy of secondary steam, recover and utilize the latent heat of secondary steam to heat the evaporated material itself, and achieve the purpose of self-heating through the self-circulation of the evaporator. Since the MVR evaporator utilizes the waste heat of steam generated by its own evaporation for recycling, it has low energy consumption and low emissions, which is in line with the requirements of energy conservation and emission reduction advocated by current environmental protection, and has huge market prospects.

[0003] The current MVR forced circulation crystallization evaporator has a gravity sedimentation crystallizer added to the lower part of the evaporator. The crystal particles are hydraulically classified in the chamber, with large particles at the bottom and small particles at the top. The upper clear liquid is pumped into the heater through a forced circulation pump for circulation heating and evaporation. The evaporated mother liquor enters the crystallizer for crystallization and stratification. Qualified crystal liquid is discharged separately through a discharge pump. This can prevent a large number of crystals from entering the forced circulation pump and heater. However, gravity sedimentation can only separate larger particles, and its efficiency is affected by factors such as fluid flow rate and particle density, resulting in poor separation effect. Utility Model Content

[0004] The purpose of the present application is to provide a hydrocyclone separation type forced circulation MVR crystallization evaporator, which increases the separation effect on crystallization.

[0005] The present application provides a hydrocyclone separation forced circulation MVR crystallization evaporator adopts the following technical solution:

[0006] A hydrocyclone separation forced circulation MVR crystallization evaporator, comprising:

[0007] A feed pipeline for conveying mother liquor;

[0008] A gravity settling tank connected to the feed pipeline and capable of receiving the mother liquor;

[0009] A heater, connected to the gravity settling tank and used to heat the mother liquor transported from the gravity settling tank;

[0010] A forced circulation pump, connected to the gravity settling tank and the heater respectively and used to transport the mother liquid in the gravity settling tank to the heater;

[0011] an evaporator, connected to the heater and capable of receiving the mother liquid delivered by the heater;

[0012] A hydrocyclone separator installed in the evaporator and capable of performing crystallization separation on the crystallization liquid, the hydrocyclone separator being connected to the gravity settling tank and capable of conveying the separated clear liquid to the gravity settling tank;

[0013] The steam compressor is connected to the heater and the evaporator respectively, and can pressurize and heat the steam evaporated in the evaporator and transport it to the heater.

[0014] By adopting the above technical scheme, the crystallization liquid is separated once by a cyclone separator, and then separated for a second time by a gravity settling tank. The crystallization liquid separated for the second time is transferred to the heater together with the mother liquor for heating. After the crystallization liquid is separated for the second time, the number of crystals in the crystallization liquid is greatly reduced, thereby reducing the blockage of the heater and the forced circulation pump.

[0015] Optionally, it also includes a first elutriation leg, which is connected to the lower end of the evaporator and is used to collect crystals separated by the cyclone separator. The first elutriation leg is connected to a discharge pump for transferring the crystals out of the first elutriation leg and collecting them.

[0016] By adopting the above technical solution, the filtered crystal liquid is collected through the setting of the first washing leg, thereby reducing the mixing of the filtered crystal liquid with the unfiltered crystal liquid, and the filtered concentrated crystal liquid is transported to the next step for further processing through the discharge pump.

[0017] Optionally, the lower end of the gravity settling tank is connected to a second washing leg for collecting crystals settled in the gravity settling tank.

[0018] By adopting the above technical solution and setting the second washing leg, the settled crystal liquid is collected, thereby reducing the mixing of the settled crystal liquid with the unsettled crystal liquid.

[0019] Optionally, the second washing leg is connected to the discharge pump.

[0020] By adopting the above technical solution, the second elutriation leg is connected with the discharge pump, and there is no need to set up a separate discharge pump to discharge the second elutriation leg, thereby reducing the production cost of the hydrocyclone separation forced circulation MVR crystallization evaporator.

[0021] Optionally, a connecting pipe is provided between the gravity settling tank and the forced circulation pump, the connecting pipe is connected to the gravity settling tank and the forced circulation pump respectively, the connecting pipe is composed of a plurality of short pipes, and an expansion joint is connected between adjacent short pipes.

[0022] By adopting the above technical solution, when the connected pipeline expands due to heat during operation, the expansion joint can absorb the thermal expansion of the pipeline through its own expansion and contraction deformation, thereby reducing the stress and displacement of the pipeline itself. By setting the expansion joint, the thermal stress of the pipeline caused by temperature changes can be effectively reduced, and the pipeline can be prevented from being ruptured or deformed due to excessive stress.

[0023] Optionally, a wire mesh demister is fixedly connected to the evaporator.

[0024] By adopting the above technical solution, when the evaporator processes liquids containing suspended matter or grease, a large amount of foam is easily generated, which will affect the evaporation efficiency and treatment effect. The wire mesh demister can effectively trap the foam on the surface, prevent it from entering the evaporation area of ​​the evaporator, and maintain the stability and efficiency of the evaporation process.

[0025] Optionally, a circulation pipeline is connected to the first washing leg, and both ends of the circulation pipeline are connected to the first washing leg.

[0026] By adopting the above technical solution and setting up the circulation pipeline, the circulating flow can prevent the crystallization liquid from stagnating inside the washing legs and forming scaling or blockage, thereby keeping the washing legs unobstructed and extending the service life of the equipment.

[0027] Optionally, a density meter is installed in the circulation pipeline.

[0028] By adopting the above technical solution, when the density meter detects that the crystal concentration of the crystallization liquid in the first washing leg is qualified, the solenoid valve is opened and the crystals are transported to the next process through the discharge pump. There is no need to transmit concentrated crystallization liquid all the time, and the discharge pump does not need to operate continuously, which saves costs.

[0029] In summary, the present application includes at least one of the following beneficial technical effects:

[0030] 1. The crystal liquid is separated once by a hydrocyclone, and then separated twice by a gravity settling tank. The crystal liquid separated twice is transferred to the heater together with the mother liquor for heating. After the crystal liquid is separated twice, the number of crystals in the crystal liquid is greatly reduced, thereby reducing the blockage of the heater and the forced circulation pump;

[0031] 2. The filtered crystal liquid is collected by setting the first elutriation leg to reduce the mixing of the filtered crystal liquid with the unfiltered crystal liquid, and the filtered concentrated crystal liquid is transported to the next process for further processing by the discharge pump;

[0032] 3. When the density meter detects that the crystal concentration of the crystal liquid in the first washing leg is qualified, the solenoid valve is opened and the crystals are transported to the next process through the discharge pump. There is no need to transmit concentrated crystal liquid all the time, and the discharge pump does not need to operate continuously, which saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the overall structure of a hydrocyclone separation forced circulation MVR crystallization evaporator according to an embodiment of the present application.

[0034] Figure 2 It is an operation flow chart of a hydrocyclone separation forced circulation MVR crystallization evaporator according to an embodiment of the present application.

[0035] In the figure, 1. gravity settling tank; 11. partition; 12. second elutriation leg; 2. heater; 3. forced circulation pump; 4. connecting pipe; 41. expansion joint; 5. evaporator; 51. wire mesh demister; 52. first elutriation leg; 6. steam compressor; 7. hydrocyclone separator; 8. discharge pump. DETAILED DESCRIPTION

[0036] The following is combined with Figure 1 -Attached Figure 2 , further details of this application are given.

[0037] Embodiment 1:

[0038] A hydrocyclone separation forced circulation MVR crystallization evaporator, refer to Figure 1 and Figure 2 , including a feed pipe, the feed pipe is connected to the mother liquid storage device, and in this embodiment, a liquid supply pump is provided on the feed pipe to extract the mother liquid in the mother liquid storage device. The mother liquid storage device can be a tank or other storage structure, as long as it can store the mother liquid.

[0039] The hydrocyclone separation forced circulation MVR crystallization evaporator also includes a gravity settling tank 1, a heater 2 and a forced circulation pump 3. The mother liquor is transported to the gravity settling tank 1 through a feed pipe. The gravity settling tank 1 is connected to the heater 2. The forced circulation pump 3 is arranged between the gravity settling tank 1 and the heater 2 and is used to transport the mother liquor in the gravity settling tank 1 to the heater 2 for heating.

[0040] Further, a connecting pipe 4 is provided between the forced circulation pump 3 and the gravity settling tank 1, and the two ends of the connecting pipe 4 are respectively connected to the forced circulation pump 3 and the gravity settling tank 1, and the connecting pipe 4 is composed of multiple short pipes, and an expansion joint 41 is provided between adjacent short pipes, and adjacent short pipes are connected to each other through the expansion joint 41. In this embodiment, there are two short pipes, and in other embodiments, the number of short pipes can be three, four or any other number. When the connecting pipe 4 is heated and expanded during operation, the expansion joint 41 can absorb the thermal expansion of the pipe through its own expansion deformation, thereby reducing the stress and displacement of the pipe itself.

[0041] The hydrocyclone separation forced circulation MVR crystallization evaporator also includes an evaporator 5 and a steam compressor 6. The evaporator 5 is connected to the heater 2 and the steam compressor 6 respectively, and the heater 2 is connected to the steam compressor 6. The mother liquor heated by the heater 2 is transported to the evaporator 5 for evaporation, and the steam formed by evaporation flows into the steam compressor 6 for compression. By compressing the steam, the temperature of the steam is increased, and the heated steam flows back into the heater 2 to heat the mother liquor in the heater 2.

[0042] Furthermore, a wire mesh demister 51 is fixedly connected to the evaporator 5. When the evaporator 5 processes liquid containing suspended matter or grease, a large amount of foam is easily generated, which will affect the evaporation efficiency and treatment effect. The wire mesh demister 51 can effectively trap the foam on the surface, prevent it from entering the evaporation area of ​​the evaporator 5, and maintain the stability and efficiency of the evaporation process.

[0043] Furthermore, the heater 2 has an inner and outer double-layer structure and the two layers are not connected. The mother liquid is transported to the inner layer of the heater 2, and the heated steam is transported to the outer layer of the heater 2. When the heated steam is transported to the outer layer of the heater 2, it exchanges heat with the mother liquid in the inner layer of the heater 2, so that the mother liquid is heated to reach the evaporation point, and the heated steam is cooled and condensed, thereby forming condensed water for recovery.

[0044] The hydrocyclone separation forced circulation MVR crystallization evaporator also includes a hydrocyclone separator 7, which is installed in the evaporator 5 and connected to the gravity settling tank 1. The hydrocyclone separator 7 performs crystallization separation on the crystallization liquid and transports the separated clear liquid to the gravity settling tank 1. The clear liquid is merged with the mother liquid that continuously enters the gravity settling tank 1 in the gravity settling tank 1 and is settled again, thereby further reducing the crystallization residue. The settled liquid flows into the forced circulation pump 3 through the gravity settling tank 1, and is transported to the heater 2 by the forced circulation pump 3 for reheating.

[0045] Furthermore, a partition 11 is provided in the gravity sedimentation tank 1, and the partition 11 divides the gravity sedimentation tank 1 into a first chamber and a second chamber. The clear liquid and the mother liquor separated by the hydrocyclone separator 7 are input into the first chamber for sedimentation, and the clear liquid formed after sedimentation overflows into the second chamber. The second chamber is connected to the forced circulation pump 3, and the settled liquid flows into the forced circulation pump 3 through the second chamber.

[0046] The bottom of the evaporator 5 is connected to a first washing leg 52. The crystals separated by the hydrocyclone 7 flow into the first washing leg 52 through the evaporator 5, and are gathered, graded, washed and cooled in the first washing leg 52. The first washing leg 52 is connected to a discharge pump 8, which transfers the cooled crystals to the next process.

[0047] Furthermore, a circulation pipe is provided on the first washing leg 52, both ends of the circulation pipe are connected to the first washing leg 52, a density meter is provided in the circulation pipe, and an electromagnetic valve is installed between the first washing leg 52 and the discharge pump 8. The electromagnetic valve is used to control the on-off between the first washing leg 52 and the discharge pump 8. When the density meter detects that the crystal concentration of the crystallization liquid in the first washing leg 52 is qualified, the electromagnetic valve is opened to transport the crystals to the next process through the discharge pump 8.

[0048] Furthermore, the lower end of the gravity settling tank 1 is connected to a second washing leg 12, which aggregates, grades, washes and cools the crystals settled in the gravity settling tank 1. The second washing leg 12 is also connected to the discharge pump 8. The second washing leg 12 is also connected to the above-mentioned circulation pipeline. Both ends of the circulation pipeline are connected to the second washing leg 12. A density meter is also arranged in the circulation pipeline. An electromagnetic valve is also arranged between the second washing leg 12 and the discharge pump 8. When the concentration of the crystal liquid in the second washing leg 12 reaches the standard, the electromagnetic valve is opened, and the discharge pump 8 transports the crystal liquid to the next process.

[0049] The implementation principle of the embodiment of the present application is as follows: after the mother liquor is transported to the gravity settling tank 1, it is mixed with the clear liquid separated by the hydrocyclone 7 and transported together to the heater 2 for heating. The heated mother liquor is transported to the evaporator 5 for evaporation, and the crystal liquid formed in the evaporator 5 is separated under the action of the hydrocyclone 7. The formed clear liquid flows into the gravity settling tank 1 for secondary separation, thereby further reducing the amount of crystallization in the liquid and reducing the possibility of clogging of the heater 2 and the forced circulation pump 3.

[0050] The embodiments of this specific implementation are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. The same components are represented by the same figure marks. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A hydrocyclone separation forced circulation MVR crystallization evaporator, characterized in that: include: A feed pipeline for conveying mother liquor; A gravity settling tank (1) is connected to the feed pipeline and is capable of receiving the mother liquor; A heater (2) is connected to the gravity settling tank (1) and is used to heat the mother liquor transported from the gravity settling tank (1); A forced circulation pump (3) is connected to the gravity settling tank (1) and the heater (2) respectively and is used to transport the mother liquid in the gravity settling tank (1) to the heater (2); an evaporator (5), which is in communication with the heater (2) and is capable of receiving the mother liquid delivered by the heater (2); a hydrocyclone separator (7), installed in the evaporator (5) and capable of performing crystallization separation on the crystallization liquid; the hydrocyclone separator (7) is connected to the gravity settling tank (1) and capable of conveying the separated clear liquid to the gravity settling tank (1); The steam compressor (6) is connected to the heater (2) and the evaporator (5) respectively, and is capable of pressurizing and heating the steam generated by evaporation in the evaporator (5) and conveying it to the heater (2).

2. A hydrocyclone separation forced circulation MVR crystallization evaporator according to claim 1, characterized in that: The device further comprises a first elutriation leg (52), the first elutriation leg (52) being connected to the lower end of the evaporator (5) and being used for collecting the crystals separated by the hydrocyclone (7), the first elutriation leg (52) being connected to a discharge pump (8) for transferring the crystals out of the first elutriation leg (52) and collecting them.

3. A hydrocyclone separation forced circulation MVR crystallization evaporator according to claim 2, characterized in that: The lower end of the gravity settling tank (1) is connected to a second elutriation leg (12) for collecting crystals settled in the gravity settling tank (1).

4. A hydrocyclone separation forced circulation MVR crystallization evaporator according to claim 3, characterized in that: The second washing leg (12) is connected to the discharge pump (8).

5. The hydrocyclone separation forced circulation MVR crystallization evaporator according to claim 1, characterized in that: A connecting pipe (4) is provided between the gravity settling tank (1) and the forced circulation pump (3), the connecting pipe (4) being connected to the gravity settling tank (1) and the forced circulation pump (3) respectively, the connecting pipe (4) being composed of a plurality of short pipe sections, and an expansion joint (41) is connected between each of adjacent short pipe sections.

6. The hydrocyclone separation forced circulation MVR crystallization evaporator according to claim 1, characterized in that: A wire mesh demister (51) is fixedly connected inside the evaporator (5).

7. The hydrocyclone separation forced circulation MVR crystallization evaporator according to claim 2, characterized in that: The first washing leg (52) is connected to a circulation pipeline, and both ends of the circulation pipeline are in communication with the first washing leg (52).

8. The hydrocyclone separation forced circulation MVR crystallization evaporator according to claim 7, characterized in that: A density meter is installed in the circulation pipeline.

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