Integrated MVR (Mechanical Vapor Recompression) evaporation system

Abstract

The utility model relates to an integrated MVR (Mechanical Vapor Recompression) evaporation system which is applied to the field of MVR evaporation technologies. A feed inlet of the feed pump is connected with a feed inlet of the falling film circulating pump, a discharge outlet of the feed pump is connected with a feed inlet of the falling film circulating pump, the I-section falling film evaporator is connected with a discharge outlet of the falling film circulating pump at a feed inlet of the shell, the I-section falling film evaporator is connected with a feed inlet of the falling film circulating pump at a discharge outlet of the shell, and the II-section forced circulation evaporator is connected with a discharge outlet of the forced circulation pump at a feed inlet of the shell. A feed port of the forced circulation pump is connected with a discharge port of the falling film circulation pump, the section II forced circulation evaporator is connected with a feed port of the crystallization chamber at a discharge port of the shell, a discharge port of the crystallization chamber is connected with a feed port of the forced circulation pump, a steam outlet of the crystallization chamber is connected with a steam inlet of the steam compressor, and a steam outlet of the steam compressor is connected with a steam inlet of the shell. And a feed port of the discharge pump is connected with a discharge port of the crystallization chamber. The section I falling film evaporator and the section II forced circulation evaporator are integrated in the shell, so that the equipment size is reduced, and the problem of heat loss caused by an overlong pipeline is solved.

Description

Technical Field

[0001] This application relates to the field of MVR evaporation technology, and in particular to an integrated MVR evaporation system. Background Technology

[0002] MVR evaporation systems are used in industrial wastewater treatment. The evaporation system utilizes the principle of evaporation concentration / evaporation crystallization to upgrade the low-quality steam generated by the system itself into a high-quality steam heat source, which is then recycled within the evaporation system. Therefore, MVR technology has significant energy-saving advantages.

[0003] Falling film evaporators are commonly used in MVR evaporation systems. In a falling film evaporator, the feed liquid enters the circulation from top to bottom. Falling film evaporators are suitable for high-viscosity materials.

[0004] Forced circulation evaporators are also commonly used in MVR evaporation systems. In a forced circulation evaporator, the liquid is forced to enter the circulation from bottom to top. Forced circulation evaporators are also suitable for high-viscosity materials.

[0005] For MVR evaporation systems, most systems currently combine falling film evaporators and forced circulation evaporators, which is more effective for concentrating materials with high viscosity at high concentrations.

[0006] For example, the prior art, patented as a sodium gulonate MVR concentration system and published under the number CN218686389U, connects a primary falling film evaporator and a secondary forced circulation evaporator in series via pipelines to evaporate and concentrate sodium gulonate residue.

[0007] In addition, for example, the prior art entitled "An MVR Energy-Saving Evaporation Crystallization System" with publication number CN214735134U also uses a falling film evaporator and a forced circulation evaporator connected in series through pipelines to treat industrial wastewater by evaporation and crystallization.

[0008] However, this method of connecting falling film evaporators and forced circulation evaporators in series with pipelines not only increases the size of the equipment, but also leads to significant heat loss and energy consumption if the pipelines are long. Utility Model Content

[0009] In order to improve the shortcomings of using falling film evaporators and forced circulation evaporators in MVR evaporation systems in series through pipelines, which not only increases the size of the equipment, but also causes serious heat loss and energy consumption problems if the pipeline is long, this application provides an integrated MVR evaporation system.

[0010] This application provides an integrated MVR evaporation system, which adopts the following technical solution:

[0011] Integrated MVR evaporation system, including,

[0012] Feed pump;

[0013] A falling film circulation pump, wherein the outlet of the feed pump is connected to the inlet of the falling film circulation pump;

[0014] An integrated evaporator includes a shell and a first-stage falling film evaporator and a second-stage forced circulation evaporator disposed in the shell. The inlet of the first-stage falling film evaporator on the shell is connected to the outlet of the falling film circulation pump, and the outlet of the first-stage falling film evaporator on the shell is connected to the inlet of the falling film circulation pump.

[0015] The forced circulation pump is connected to the inlet of the second-stage forced circulation evaporator and the outlet of the forced circulation pump on the shell. The inlet of the forced circulation pump is also connected to the outlet of the falling film circulation pump.

[0016] The discharge port of the II-stage forced circulation evaporator on the shell is connected to the inlet of the crystallization chamber, and the discharge port of the crystallization chamber is connected to the inlet of the forced circulation pump.

[0017] An electric valve is installed on the pipeline connecting the discharge port of the falling film circulating pump and the inlet of the first-stage falling film evaporator on the shell. An electric valve is installed on the pipeline connecting the discharge port of the falling film circulating pump and the inlet of the forced circulation pump.

[0018] The steam compressor is connected to the steam outlet of the crystallization chamber and the steam inlet of the steam compressor, and the steam outlet of the steam compressor is connected to the steam inlet on the casing.

[0019] A discharge pump, the inlet of which is connected to the outlet of the crystallization chamber.

[0020] By adopting the above technical solution, after the raw material liquid enters the MVR evaporation system from the feed pump, it first passes through the first-stage falling film evaporator for circulation and concentration, and then enters the second-stage forced circulation evaporator for further circulation and concentration until the concentrated liquid reaches the standard and is discharged from the discharge pump in the form of crystal slurry. During this process, the steam generated in the crystallization chamber is forcibly compressed by the steam compressor to become high-quality regenerated steam. The regenerated steam then provides a heat source for the evaporator, thereby reducing the MVR evaporation system's demand for external energy. The technical solution of this application integrates the first-stage falling film evaporator and the second-stage forced circulation evaporator into a shell, that is, the first-stage falling film evaporator and the second-stage forced circulation evaporator share a single shell. This not only reduces the equipment size and saves equipment space, but also solves the problem of excessive heat loss and energy consumption caused by excessively long equipment connection pipelines.

[0021] Optionally, it also includes a primary plate preheater and a vacuum pump, with the inlet of the primary plate preheater connected to the outlet of the feed pump, and the outlet of the primary plate preheater connected to the inlet of the falling film circulation pump; the steam outlet on the shell is connected to the heat medium inlet of the primary plate preheater, and the inlet of the vacuum pump is connected to the heat medium outlet of the primary plate preheater.

[0022] By adopting the above technical solution, the steam delivered from the evaporator is recovered and reused in the first-stage plate preheater. The steam is used as a heat medium to preheat the raw material liquid, which can make full use of the steam energy produced by the system and improve the concentration treatment effect of the raw material liquid after entering the evaporator. The vacuum pump is used to pump out and discharge the steam energy used by the system.

[0023] Optionally, it also includes a secondary plate preheater and a condensate pump, wherein the inlet of the secondary plate preheater is connected to the outlet of the primary plate preheater, and the outlet of the secondary plate preheater is connected to the inlet of the falling film circulation pump; the condensate outlet on the shell is connected to the heat medium inlet of the secondary plate preheater, and the inlet of the condensate pump is connected to the heat medium outlet of the secondary plate preheater.

[0024] By adopting the above technical solution, the superheated condensate from the evaporator is recycled to the secondary plate preheater. The superheated condensate is used as a heat medium to further preheat the raw material liquid. Based on the primary plate preheater, the secondary plate preheater further heats the raw material liquid, making the concentration treatment effect of the raw material liquid better after entering the evaporator. Secondly, the superheated condensate energy produced by the MVR evaporation system is fully utilized, which is both energy-saving and efficient. The condensate pump is used to pump out and discharge the superheated condensate energy used by the system.

[0025] Optionally, it also includes a condensate tank, the inlet of which is connected to the heat medium outlet of the secondary plate preheater, and the outlet of which is connected to the inlet of the condensate pump.

[0026] By adopting the above technical solution, after the superheated condensate is used as a heat medium in the two-stage plate preheater, it can be temporarily stored in the condensate tank and cooled down naturally for a period of time before being discharged from the condensate pump, thereby improving the overall safety of the MVR evaporation system.

[0027] Optionally, the outlet of the condensate pump is connected to the spray nozzle on the shell of the integrated evaporator, and the outlet of the condensate pump is also connected to the spray nozzle of the crystallization chamber.

[0028] By adopting the above technical solution, after the superheated condensate is used up by the two-stage plate preheater, it is temporarily stored in the condensate tank. The condensate can be recycled to the evaporator and crystallization chamber using a condensate pump to clean the inside of the evaporator and crystallization chamber.

[0029] Optionally, it also includes a flash tank, the inlet of which is connected to the condensate outlet on the shell, and the outlet of which is connected to the heat medium inlet of the secondary plate preheater.

[0030] By adopting the above technical solution, the superheated condensate delivered from the evaporator first enters the flash tank and then enters the secondary plate preheater as a heat medium. The flash tank provides space for rapid vapor-liquid separation of the superheated condensate, and the generated steam is recovered and reused. The separated superheated condensate continues to enter the secondary plate preheater.

[0031] Optionally, the steam outlet of the flash tank is connected to the steam inlet of the steam compressor.

[0032] By adopting the above technical solution, the steam generated by the flash tank can be recovered and reused in the evaporator, making full use of the steam energy produced by the system, which is both energy-saving and efficient.

[0033] Optionally, the integrated evaporator housing is equipped with a fresh steam inlet.

[0034] By adopting the above technical solution, high-quality steam can be added to the system through the fresh steam inlet, thereby improving the effect of concentrated liquid circulation and concentration treatment.

[0035] In summary, this application includes the following beneficial technical effects:

[0036] 1. After the feed liquid enters the MVR evaporation system from the feed pump, it is first preheated by the first-stage plate preheater and the second-stage plate preheater, and then circulated and concentrated by the first-stage falling film evaporator and the second-stage forced circulation evaporator until the concentrated liquid reaches the standard and is discharged from the discharge pump in the form of crystal slurry. During this process, the steam generated in the crystallization chamber and flash tank is forcibly compressed by the steam compressor and converted into high-quality regenerated steam. The regenerated steam then provides a heat source for the first-stage falling film evaporator and the second-stage forced circulation evaporator, thereby reducing the MVR evaporation system's demand for external energy.

[0037] 2. The technical solution of this application integrates the I-stage falling film evaporator and the II-stage forced circulation evaporator into a shell to form an integrated evaporator. That is, the I-stage falling film evaporator and the II-stage forced circulation evaporator share a shell and are an integrated structure. This not only reduces the size of the equipment and saves the space occupied by the equipment, but also solves the problem of excessive heat loss and excessive energy consumption caused by excessively long equipment connection pipelines. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the integrated MVR evaporation system in this embodiment.

[0039] Reference numerals: 1. Feed pump; 2. Falling film circulation pump; 3. Integrated evaporator; 31. Shell; 32. Stage I falling film evaporator; 33. Stage II forced circulation evaporator; 4. Crystallization chamber; 5. Electric valve one; 6. Electric valve two; 7. Steam compressor; 8. Discharge pump; 9. First-stage plate preheater; 10. Vacuum pump; 11. Second-stage plate preheater; 12. Condensate pump; 13. Condensate tank; 14. Flash tank; 15. Forced circulation pump; 16. Fresh steam inlet. Detailed Implementation

[0040] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

[0041] This embodiment discloses an integrated MVR evaporation system, referring to... Figure 1 The evaporator in the integrated MVR evaporation system integrates a first-stage falling film evaporator 32 and a second-stage forced circulation evaporator 33 into a shell 31, forming an integrated evaporator 3 with a one-piece structure. This not only reduces the size of the equipment and saves space, but also solves the problem of severe heat loss and energy consumption caused by excessively long connecting pipelines. The MVR evaporation system in this embodiment is suitable for materials with high viscosity in the high-concentration range. Specifically, the first-stage falling film evaporator 32 and the second-stage forced circulation evaporator 33 are integrated into the shell 31, and baffles are provided at both ends of the shell 31, making the first-stage falling film evaporator 32 and the second-stage forced circulation evaporator 33 independent structures. This allows the concentrate to be circulated and concentrated in the first-stage falling film evaporator 32 before entering the second-stage forced circulation evaporator 33 for further circulation and concentration, ultimately obtaining a higher quality crystal slurry product.

[0042] Reference Figure 1 A feed pump 1 is installed at the initial end of the MVR evaporation system. The raw material liquid to be processed enters the system from the feed pump 1. The outlet of the feed pump 1 is connected to the inlet of the first-stage plate preheater 9. The outlet of the first-stage plate preheater 9 is connected to the inlet of the second-stage plate preheater 11. The outlet of the second-stage plate preheater 11 is connected to the inlet of the falling film circulation pump 2. The outlet of the first-stage falling film evaporator 32 on the shell 31 is also connected to the inlet of the falling film circulation pump 2. The outlet of the falling film circulation pump 2 is connected to the inlet of the first-stage falling film evaporator 32 on the shell 31.

[0043] For the primary plate preheater 9, the heat medium inlet of the primary plate preheater 9 is connected to the steam outlet on the shell 31 of the integrated evaporator 3. The steam delivered from the integrated evaporator 3 is recycled and enters the primary plate preheater 9 to preheat the feed liquid. The heat medium outlet of the primary plate preheater 9 is connected to the inlet of the vacuum pump 10, which ultimately discharges the steam from the system. For the secondary plate preheater 11, the heat medium inlet of the secondary plate preheater 11 is connected to the condensate outlet on the shell 31 of the integrated evaporator 3. The superheated condensate delivered from the integrated evaporator 3 is recycled and enters the secondary plate preheater 11 to preheat the feed liquid a second time. This increases the overall temperature of the feed liquid before it enters the integrated evaporator 3, thus improving the concentration effect of the concentrate in the integrated evaporator 3. The heat medium outlet of the secondary plate preheater 11 is connected to the inlet of the condensate pump 12, which ultimately discharges the condensate from the system.

[0044] It should be noted that a condensate tank 13 is installed between the secondary plate preheater 11 and the condensate pump 12. The heat medium outlet of the secondary plate preheater 11 is connected to the inlet of the condensate tank 13, while the outlet of the condensate tank 13 is connected to the inlet of the condensate pump 12. The condensate tank 13 temporarily stores the superheated condensate discharged from the primary plate preheater 9 for a period of time before it is discharged from the condensate pump 12. The superheated condensate in the condensate tank 13 cools down naturally, resulting in a lower temperature condensate discharge and a higher safety factor. Alternatively, the system condensate can be used to spray and clean the interior of the integrated evaporator 3 and the crystallization chamber 4. This can be achieved by connecting the outlet of the condensate pump 12 to the spray nozzle on the shell 31 of the integrated evaporator 3 and the spray nozzle on the crystallization chamber 4.

[0045] Reference Figure 1After the raw material liquid is preheated by the first-stage plate preheater 9 and the second-stage plate preheater 11, it is forced into the first-stage falling film evaporator 32 from top to bottom by the falling film circulation pump 2. It is then circulated and concentrated in the first-stage falling film evaporator 32, and then enters the second-stage forced circulation evaporator 33. The feed inlet of the second-stage forced circulation evaporator 33 on the shell 31 is connected to the discharge outlet of the forced circulation pump 15, while the feed inlet of the forced circulation pump 15 is connected to the discharge outlet of the falling film circulation pump 2. It should be noted that an electric valve 5 is installed on the pipeline connecting the discharge outlet of the falling film circulation pump 2 and the feed inlet of the first-stage falling film evaporator 32 on the shell 31, and an electric valve 6 is installed on the pipeline connecting the discharge outlet of the falling film circulation pump 2 and the feed inlet of the forced circulation pump 15. When the concentrate is first circulated in the first-stage falling film evaporator 32, electric valve 5 is open and electric valve 6 is closed. After the concentrate finishes its treatment in the first-stage falling film evaporator 32, it enters the second-stage forced circulation evaporator. When the evaporator is in stage 33, electric valve 5 is closed and electric valve 6 is open. In this way, the concentrated liquid is forced from bottom to top into the stage II forced circulation evaporator 33 by the forced circulation pump 15 for further concentration and circulation. The outlet of the stage II forced circulation evaporator 33 on the shell 31 is connected to the inlet of the crystallization chamber 4, and the outlet of the crystallization chamber 4 is connected to the inlet of the forced circulation pump 15. The crystallization chamber 4 can continuously perform vapor-liquid separation on the concentrated liquid circulating in the stage II forced circulation evaporator 33. The resulting concentrated liquid is then re-entered into the stage II forced circulation evaporator 33 for further concentration and circulation. The generated steam is discharged from the steam outlet of the crystallization chamber 4 and recycled back to the integrated evaporator 3.

[0046] A discharge pump 8 is installed at the end of the MVR evaporation system. The inlet of the discharge pump 8 is connected to the outlet of the crystallization chamber 4. When the concentrate reaches the standard, it is discharged from the discharge pump 8 in the form of crystal slurry.

[0047] Reference Figure 1In this application, the steam used in the integrated evaporator 3 of the MVR evaporation system comes from the crystallization chamber 4 and the flash tank 14. The steam outlet of the crystallization chamber 4 is connected to the steam inlet of the steam compressor 7, and the steam outlet of the steam compressor 7 is connected to the steam inlet on the shell 31 of the integrated evaporator 3. In this way, the steam generated in the crystallization chamber 4 is forcibly compressed by the steam compressor 7 and converted into high-quality regenerated steam. The regenerated steam then provides a heat source for the integrated evaporator 3, thereby reducing the demand of the MVR evaporation system for external energy. The steam delivered from the integrated evaporator 3 is then recycled to the first-stage plate preheater 9. The entire MVR evaporation system is highly efficient and energy-saving. The flash tank 14 is located between the heat medium inlet of the secondary plate preheater 11 and the condensate outlet on the shell 31 of the integrated evaporator 3. The inlet of the flash tank 14 is connected to the condensate outlet on the shell 31 of the integrated evaporator 3, while the outlet of the flash tank 14 is connected to the heat medium inlet of the secondary plate preheater 11. The steam outlet of the flash tank 14 is connected to the steam inlet of the steam compressor 7. After being discharged from the integrated evaporator 3, the superheated condensate first enters the flash tank 14 and then enters the secondary plate preheater 11. The flash tank 14 provides space for rapid vapor-liquid separation of the superheated condensate. The generated steam is recycled back to the integrated evaporator 3, while the separated superheated condensate continues to be used in the secondary plate preheater 11, improving the efficiency and energy saving of the entire MVR evaporation system.

[0048] It should be noted that if the MVR evaporation system does not produce enough steam, the steam heat source can be supplemented to the system through the fresh steam inlet 16 on the shell 31 of the integrated evaporator 3.

[0049] The implementation principle of the integrated MVR evaporation system in this embodiment is as follows: After the raw material liquid enters the MVR evaporation system from the feed pump 1, it is first preheated by the first-stage plate preheater 9 and the second-stage plate preheater 11, and then circulated and concentrated by the first-stage falling film evaporator 32 and the second-stage forced circulation evaporator 33 until the concentrated liquid reaches the standard and is discharged from the discharge pump 8 in the form of crystal slurry. During this process, the steam generated by the crystallization chamber 4 and the flash tank 14 is forcibly compressed by the steam compressor 7 and transformed into high-quality regenerated steam. The regenerated steam then provides a heat source for the first-stage falling film evaporator 32 and the second-stage forced circulation evaporator 33, thereby reducing the demand of the MVR evaporation system for external energy. The technical solution of this application integrates the first-stage falling film evaporator 32 and the second-stage forced circulation evaporator 33 into a shell to form an integrated evaporator 3. That is, the first-stage falling film evaporator 32 and the second-stage forced circulation evaporator 33 share a shell 31, which is an integral structure. This not only reduces the size of the equipment and saves the space occupied by the equipment, but also solves the problem of excessive heat loss and excessive energy consumption caused by excessively long equipment connection pipelines.

[0050] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An integrated MVR evaporation system, characterized in that, include, Feed pump (1); The falling film circulation pump (2) is connected to the discharge port of the feed pump (1) and the inlet of the falling film circulation pump (2); An integrated evaporator (3) includes a shell (31) and a first-stage falling film evaporator (32) and a second-stage forced circulation evaporator (33) disposed in the shell (31). The inlet of the first-stage falling film evaporator (32) on the shell (31) is connected to the outlet of the falling film circulation pump (2), and the outlet of the first-stage falling film evaporator (32) on the shell (31) is connected to the inlet of the falling film circulation pump (2). The forced circulation pump (15), the inlet of the second-stage forced circulation evaporator (33) on the shell (31) is connected to the outlet of the forced circulation pump (15), and the inlet of the forced circulation pump (15) is connected to the outlet of the falling film circulation pump (2). The outlet of the crystallization chamber (4) and the inlet of the II-stage forced circulation evaporator (33) on the shell (31) are connected to the inlet of the crystallization chamber (4), and the outlet of the crystallization chamber (4) is connected to the inlet of the forced circulation pump (15). Electric valve 1 (5) is installed on the pipeline connecting the outlet of the falling film circulation pump (2) and the inlet of the first stage falling film evaporator (32) on the shell (31), and electric valve 2 (6) is installed on the pipeline connecting the outlet of the falling film circulation pump (2) and the inlet of the forced circulation pump (15). The steam compressor (7) is connected to the steam outlet of the crystallization chamber (4) and the steam inlet of the steam compressor (7), and the steam outlet of the steam compressor (7) is connected to the steam inlet on the casing (31); The discharge pump (8) is connected to the discharge port of the crystallization chamber (4).

2. The integrated MVR evaporation system according to claim 1, characterized in that, It also includes a primary plate preheater (9) and a vacuum pump (10). The inlet of the primary plate preheater (9) is connected to the outlet of the feed pump (1), and the outlet of the primary plate preheater (9) is connected to the inlet of the falling film circulation pump (2). The steam outlet on the shell (31) is connected to the heat medium inlet of the primary plate preheater (9), and the inlet of the vacuum pump (10) is connected to the heat medium outlet of the primary plate preheater (9).

3. The integrated MVR evaporation system according to claim 2, characterized in that, It also includes a secondary plate preheater (11) and a condensate pump (12). The inlet of the secondary plate preheater (11) is connected to the outlet of the primary plate preheater (9), and the outlet of the secondary plate preheater (11) is connected to the inlet of the falling film circulation pump (2). The condensate outlet on the shell (31) is connected to the heat medium inlet of the secondary plate preheater (11), and the inlet of the condensate pump (12) is connected to the heat medium outlet of the secondary plate preheater (11).

4. The integrated MVR evaporation system according to claim 3, characterized in that, It also includes a condensate tank (13), the inlet of which is connected to the heat medium outlet of the secondary plate preheater (11), and the outlet of which is connected to the inlet of the condensate pump (12).

5. The integrated MVR evaporation system according to claim 3, characterized in that, The outlet of the condensate pump (12) is connected to the spray port on the shell (31) of the integrated evaporator (3), and the outlet of the condensate pump (12) is also connected to the spray port of the crystallization chamber (4).

6. The integrated MVR evaporation system according to claim 3, characterized in that, It also includes a flash tank (14), the inlet of which is connected to the condensate outlet on the shell (31), and the outlet of which is connected to the heat medium inlet of the secondary plate preheater (11).

7. The integrated MVR evaporation system according to claim 6, characterized in that, The steam outlet of the flash tank (14) is connected to the steam inlet of the steam compressor (7).

8. The integrated MVR evaporation system according to claim 1, characterized in that, The integrated evaporator (3) has a fresh steam inlet (16) on its shell (31).

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