Low-temperature efficient MVR evaporator

Abstract

The invention discloses a low-temperature efficient MVR evaporator which comprises a vacuum pump, an evaporating tank, a filter, a forced circulation pump, a first forced circulation plate heat exchanger, a booster fan, a condensate water tank and a second forced circulation plate heat exchanger. A high-concentration wastewater outlet is formed in the first forced circulation plate heat exchanger; the bottom of the evaporation tank is sequentially connected with a filter and a forced circulation pump through a pipeline, and then the pipeline is connected to a high-concentration wastewater outlet pipeline; the first forced circulation plate heat exchanger and the second forced circulation plate heat exchanger are each internally provided with a vibration plate set, each vibration plate set comprises an isolation plate, a vibration plate and a common plate, each vibration plate is located between the corresponding isolation plate and the corresponding common plate, and the surface of each common plate is coated with a hydrophobic PDMS coating. On one hand, the surface of the heat exchange plate is coated with the hydrophobic PDMS coating, and on the other hand, water flow scaling is interfered by inserting the vibrating reed for resonance, so that the purpose of enhancing the anti-scaling performance of the plate heat exchanger is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a low-temperature and high-efficiency MVR evaporator. Background Art

[0003] Evaporation and crystallization is an effective way to treat high-salt wastewater. Mechanical vapor compression (MVR) technology is considered to be the most advanced evaporation and crystallization technology in the world for its advantages of energy saving, water saving, pollution-free, and recyclable crystallized salt. Compared with traditional evaporation systems, the MVR system only needs to introduce raw steam as a heat source at startup. When secondary steam is generated, the system operates stably without the need for an external heat source, greatly reducing energy consumption and operating costs. In addition, the equipment occupies a small area, is easy to operate, and has low safety hazards. At present, MVR technology is being widely used in wastewater treatment in industries such as chemical, pharmaceutical, food, and photovoltaic industries due to its technical characteristics and advantages.

[0004] However, traditional evaporators are prone to scaling during the treatment process, which requires regular cleaning of the evaporator equipment, greatly affecting production efficiency. Scaling mainly occurs on the heat exchanger of the device. The current cleaning method mainly uses chemical cleaning or disassembly cleaning, which has high chemical costs and is time-consuming and labor-intensive.

[0005] In summary, there is an urgent need to find an effective method to effectively enhance the operating performance of the evaporator by reducing the accumulation of dirt on the heat exchanger plates, thereby improving the practicality of MVR. Summary of the invention

[0006] In order to solve the above technical problems existing in the prior art, the present invention provides a low-temperature and high-efficiency MVR evaporator and its application, which improves the production efficiency of the evaporator by avoiding frequent scaling of the heat exchanger plates. For the heat exchanger plates, on the one hand, a hydrophobic PDMS coating can be applied on the surface thereof, and on the other hand, the scaling of the water flow can be disturbed by inserting a vibration plate to resonate, thereby achieving the purpose of strengthening the anti-scaling performance of the plate heat exchanger.

[0007] The technical solution adopted by the present invention is:

[0008] A low-temperature and high-efficiency MVR evaporator, characterized in that it comprises a vacuum pump (1), an evaporation tank (2), a filter (3), a forced circulation pump (4), a first forced circulation plate heat exchanger (5), a booster fan (6), a condensed water tank (7) and a second forced circulation plate heat exchanger (8), wherein the lower part of the side wall of the evaporation tank (2) and the second forced circulation plate heat exchanger (8) are both provided with an inlet for raw wastewater; wherein:

[0009] The vacuum pump (1) is installed on the upper part of the side wall of the evaporation tank (2); the evaporation tank (2), the first forced circulation plate heat exchanger (5) and the booster fan (6) are connected in sequence through pipelines to form a circulation loop; a high-concentration wastewater outlet is provided on the first forced circulation plate heat exchanger (5); the bottom of the evaporation tank (2) is connected to the filter (3) and the forced circulation pump (4) in sequence through pipelines, and then the pipelines are connected to the high-concentration wastewater outlet pipeline; the first forced circulation plate heat exchanger (5) is connected to the top of the condensate tank (7) through pipelines, the bottom of the condensate tank (7) is connected to the second forced circulation plate heat exchanger (8) through pipelines, and the second forced circulation plate heat exchanger (8) is connected to the raw wastewater inlet pipeline on the evaporation tank (2) through pipelines;

[0010] A vibration plate group (9) is installed inside the first forced circulation plate heat exchanger (5) and the second forced circulation plate heat exchanger (8), respectively. The vibration plate group (9) includes an isolation plate (91), a vibration plate (92) and an ordinary plate (93). The vibration plate (92) is located between the isolation plate (91) and the ordinary plate (93). The vibration plate (92) transmits vibration energy to the ordinary plate (93).

[0011] Furthermore, the vibration plate groups are provided in 1 to 5 groups and are evenly distributed in the first forced circulation plate heat exchanger (5) or the second forced circulation plate heat exchanger (8).

[0012] Furthermore, the four sides of the isolation plate (91), the vibration plate (92) and the ordinary plate (93) are respectively closed by sealing rings to prevent water from flowing through; the vibration plate (92) is partially hollowed out to form a vibration sheet to drive the transmission of vibration energy between the isolation plate (91) and the ordinary plate (93).

[0013] Furthermore, the vibration plate (92) operates intermittently through a timer control.

[0014] Furthermore, the surface of the common plate (93) is coated with a hydrophobic PDMS coating.

[0015] Furthermore, the material flow rate in the first forced circulation plate heat exchanger (5) or the second forced circulation plate heat exchanger (8) is 1.5 to 2 m / s.

[0016] Further, the preparation method of the PDMS coating is as follows:

[0017] Dissolve polydimethylsiloxane (PDMS) in n-hexane, add tetraethyl orthosilicate (TEOS) and dibutyltin laurate (DBTDL), stir and mix evenly, and then ultrasonically treat for 5 to 20 minutes and then stand at room temperature for crosslinking for 2 to 6 hours to obtain a PDMS pre-crosslinking solution.

[0018] Furthermore, the volume amount of n-hexane is 10-30 mL / g based on the mass of PDMS.

[0019] Furthermore, the mass ratio of the PDMS, tetraethyl orthosilicate and dibutyltin laurate is 50-100:1-10:1.

[0020] Furthermore, the ratio of the amount of the PDMS solution to the area of ​​the ordinary plate is 0.1 to 0.5 mL / cm 2 .

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] (1) The present invention inserts a vibration plate group into the heat exchanger, and the strong vibration generated is transmitted to other metal plates, thereby interfering with the water flow and causing scaling on the heat exchanger plates;

[0023] (2) The present invention further enhances the anti-scaling capability of the heat exchanger by coating a hydrophobic PDMS coating on the surface of the metal plate of the heat exchanger;

[0024] (3) The present invention improves the anti-scaling ability of the heat exchanger by providing a filter, thereby reducing the need for frequent cleaning of the heat exchanger and improving the production efficiency of the MVR evaporator. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a process flow chart of a forced circulation MVR evaporator in the present invention;

[0026] Figure 2 It is the vibrating plate group in the forced circulation plate heat exchanger of the present invention;

[0027] FIG3 is an isolation plate and a vibration plate in the vibration plate group of the present invention;

[0028] Figure 4 It is a common plate in the forced circulation plate heat exchanger of the present invention;

[0029] Figure 5 It is the forced circulation plate heat exchanger in the present invention. DETAILED DESCRIPTION

[0030] The present invention is described in detail below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments. Without departing from the content and scope of the present invention, changes in implementation should be included in the technical scope of the present invention.

[0031] Embodiment 1:

[0032] A low-temperature and high-efficiency MVR evaporator, characterized in that it comprises a vacuum pump 1, an evaporation tank 2, a filter 3, a forced circulation pump 4, a first forced circulation plate heat exchanger 5, a booster fan 6, a condensed water tank 7 and a second forced circulation plate heat exchanger 8, wherein the lower part of the side wall of the evaporation tank 2 and the second forced circulation plate heat exchanger 8 are provided with an inlet for raw wastewater; wherein:

[0033] The vacuum pump 1 is installed on the upper part of the side wall of the evaporation tank 2, and the evaporation tank 2, the first forced circulation plate heat exchanger 5 and the booster fan 6 are connected in sequence through pipelines to form a circulation loop; the first forced circulation plate heat exchanger 5 is provided with a high-concentration wastewater outlet, and the bottom of the evaporation tank 2 is connected to the filter 3 and the forced circulation pump 4 in sequence through pipelines, and then the pipelines are connected to the high-concentration wastewater outlet pipeline; the first forced circulation plate heat exchanger 5 is connected to the top of the condensed water tank 7 through a pipeline, and the bottom of the condensed water tank 7 is connected to the second forced circulation plate heat exchanger 8 through a pipeline, and the second forced circulation plate heat exchanger 8 is connected to the inlet pipeline of the original wastewater on the evaporation tank 2 through a pipeline;

[0034] A vibration plate group 9 is installed inside the first forced circulation plate heat exchanger 5 and the second forced circulation plate heat exchanger 8, respectively. The vibration plate group 9 includes an isolation plate 91, a vibration plate 92 and an ordinary plate 93. The vibration plate 92 is located between the isolation plate 91 and the ordinary plate 93. The vibration plate 92 transfers vibration energy to the ordinary plate 93.

[0035] There are three groups of vibration plates, which are evenly distributed in the first forced circulation plate heat exchanger 6 or the second forced circulation plate heat exchanger 8. The sealing rings around the isolation plate are closed to prevent water from flowing through; the vibration plate is partially hollowed out on the basis of the isolation plate to form a vibration plate, which can drive the transmission of vibration energy between the front and rear plates; the vibration plate can be controlled to run intermittently by a timer; the surface of the ordinary plate 93 is coated with a hydrophobic PDMS coating 13.

[0036] The PDMS coating 13 is configured as follows: 6.835 g of PDMS is added to 192 mL of n-hexane, and then 0.6835 g of TEOS and 0.1367 g of DBTDL are added, stirred for 10 min, ultrasonicated for 20 min, and crosslinked at room temperature for 2 h to obtain 200 mL of PDMS pre-crosslinking solution, which is evenly coated on the surface of the ordinary plate 93. The material flow rate in the forced circulation heat exchanger is set to 2 m / s.

[0037] The low-temperature and high-efficiency MVR evaporator can produce normally at a load of 50-120%, with low steam energy consumption and high energy efficiency. Its thermal efficiency is 20 times that of a single-effect flash system or more than 5 times that of a four-effect flash system.

[0038] Embodiment 2:

[0039] A low-temperature and high-efficiency MVR evaporator, characterized in that it comprises a vacuum pump 1, an evaporation tank 2, a filter 3, a forced circulation pump 4, a first forced circulation plate heat exchanger 5, a booster fan 6, a condensed water tank 7 and a second forced circulation plate heat exchanger 8, wherein the lower part of the side wall of the evaporation tank 2 and the second forced circulation plate heat exchanger 8 are provided with an inlet for raw wastewater; wherein:

[0040] The vacuum pump 1 is installed on the upper part of the side wall of the evaporation tank 2, and the evaporation tank 2, the first forced circulation plate heat exchanger 5 and the booster fan 6 are connected in sequence through pipelines to form a circulation loop; the first forced circulation plate heat exchanger 5 is provided with a high-concentration wastewater outlet, and the bottom of the evaporation tank 2 is connected to the filter 3 and the forced circulation pump 4 in sequence through pipelines, and then the pipelines are connected to the high-concentration wastewater outlet pipeline; the first forced circulation plate heat exchanger 5 is connected to the top of the condensed water tank 7 through a pipeline, and the bottom of the condensed water tank 7 is connected to the second forced circulation plate heat exchanger 8 through a pipeline, and the second forced circulation plate heat exchanger 8 is connected to the inlet pipeline of the original wastewater on the evaporation tank 2 through a pipeline;

[0041] A vibration plate group 9 is installed inside the first forced circulation plate heat exchanger 5 and the second forced circulation plate heat exchanger 8, respectively. The vibration plate group 9 includes an isolation plate 91, a vibration plate 92 and an ordinary plate 93. The vibration plate 92 is located between the isolation plate 91 and the ordinary plate 93. The vibration plate 92 transfers vibration energy to the ordinary plate 93.

[0042] There are three groups of vibration plates, which are evenly distributed in the first forced circulation plate heat exchanger 6 or the second forced circulation plate heat exchanger 8. The sealing rings around the isolation plate are closed to prevent water from flowing through; the vibration plate is partially hollowed out on the basis of the isolation plate to form a vibration plate, which can drive the transmission of vibration energy between the front and rear plates; the vibration plate can be controlled to run intermittently by a timer; the surface of the ordinary plate 93 is coated with a hydrophobic PDMS coating 13.

[0043] The configuration of the PDMS coating 13 is as follows: 10.259 g of PDMS is added to 192 mL of n-hexane, and then 1.0259 g of TEOS and 0.2052 g of DBTDL are added, stirred for 10 min, ultrasonicated for 20 min, and crosslinked at room temperature for 2 h to obtain 200 mL of PDMS pre-crosslinking solution, which is evenly coated on the surface of the ordinary plate 93. The material flow rate in the forced circulation heat exchanger is set to 2 m / s.

[0044] The low-temperature and high-efficiency MVR evaporator can produce normally at a load of 50-120%, with low steam energy consumption and high energy efficiency. Its thermal efficiency is 20 times that of a single-effect flash system or more than 5 times that of a four-effect flash system.

[0045] Embodiment 3:

[0046] A low-temperature and high-efficiency MVR evaporator, characterized in that it comprises a vacuum pump 1, an evaporation tank 2, a filter 3, a forced circulation pump 4, a first forced circulation plate heat exchanger 5, a booster fan 6, a condensed water tank 7 and a second forced circulation plate heat exchanger 8, wherein the lower part of the side wall of the evaporation tank 2 and the second forced circulation plate heat exchanger 8 are provided with an inlet for raw wastewater; wherein:

[0047] The vacuum pump 1 is installed on the upper part of the side wall of the evaporation tank 2, and the evaporation tank 2, the first forced circulation plate heat exchanger 5 and the booster fan 6 are connected in sequence through pipelines to form a circulation loop; the first forced circulation plate heat exchanger 5 is provided with a high-concentration wastewater outlet, and the bottom of the evaporation tank 2 is connected to the filter 3 and the forced circulation pump 4 in sequence through pipelines, and then the pipelines are connected to the high-concentration wastewater outlet pipeline; the first forced circulation plate heat exchanger 5 is connected to the top of the condensed water tank 7 through a pipeline, and the bottom of the condensed water tank 7 is connected to the second forced circulation plate heat exchanger 8 through a pipeline, and the second forced circulation plate heat exchanger 8 is connected to the inlet pipeline of the original wastewater on the evaporation tank 2 through a pipeline;

[0048] A vibration plate group 9 is installed inside the first forced circulation plate heat exchanger 5 and the second forced circulation plate heat exchanger 8, respectively. The vibration plate group 9 includes an isolation plate 91, a vibration plate 92 and an ordinary plate 93. The vibration plate 92 is located between the isolation plate 91 and the ordinary plate 93. The vibration plate 92 transfers vibration energy to the ordinary plate 93.

[0049] There are three groups of vibration plates, which are evenly distributed in the first forced circulation plate heat exchanger 6 or the second forced circulation plate heat exchanger 8. The sealing rings around the isolation plate are closed to prevent water from flowing through; the vibration plate is partially hollowed out on the basis of the isolation plate to form a vibration plate, which can drive the transmission of vibration energy between the front and rear plates; the vibration plate can be controlled to run intermittently by a timer; the surface of the ordinary plate 93 is coated with a hydrophobic PDMS coating 13.

[0050] The configuration of the PDMS coating 13 is as follows: 14.059 g of PDMS is added to 192 mL of n-hexane, and then 1.4059 g of TEOS and 0.2812 g of DBTDL are added, stirred for 10 min, ultrasonicated for 20 min, and crosslinked at room temperature for 2 h to obtain 200 mL of PDMS pre-crosslinking solution, which is evenly coated on the surface of the ordinary plate 93. The material flow rate in the forced circulation heat exchanger is set to 2 m / s.

[0051] The low-temperature and high-efficiency MVR evaporator can produce normally at a load of 50-120%, with low steam energy consumption and high energy efficiency. Its thermal efficiency is 20 times that of a single-effect flash system or more than 5 times that of a four-effect flash system.

[0052] Comparative Example 1:

[0053] A low-temperature and high-efficiency MVR evaporator mainly comprises the following structure: a vacuum pump 1, an evaporation tank 2, a filter 3, a forced circulation pump 4, a first forced circulation plate heat exchanger 5, a booster fan 6, a condensate tank 7 and a second forced circulation plate heat exchanger 8. The first and second forced circulation plate heat exchangers are equipped with vibration plate groups, which can transfer vibration energy to ordinary plates in the heat exchanger.

[0054] There are three groups of vibration plate groups, which are evenly distributed in the first forced circulation plate heat exchanger 6 or the second forced circulation plate heat exchanger 8 .

[0055] The isolation plate is closed by sealing rings on all sides to prevent water from flowing through; the vibration plate is partially hollowed out on the basis of the isolation plate to form a vibration plate, which can drive the transmission of vibration energy between the front and rear plates; the vibration plate can be controlled to run intermittently through a timer; the material flow rate in the forced circulation heat exchanger is set to 2m / s.

[0056] Comparative Example 2:

[0057] A low-temperature and high-efficiency MVR evaporator mainly comprises the following structure: a vacuum pump 1, an evaporation tank 2, a filter 3, a forced circulation pump 4, a first forced circulation plate heat exchanger 5, a booster fan 6, a condensed water tank 7 and a second forced circulation plate heat exchanger 8, wherein the surfaces of the metal plates in the first and second forced circulation plate heat exchangers are coated with a hydrophobic PDMS coating.

[0058] The PDMS coating was prepared by adding 6.835 g PDMS to 192 mL n-hexane, adding 0.6835 g TEOS and 0.1367 g DBTDL, stirring for 10 min, ultrasonicating for 20 min, and standing at room temperature for 2 h for crosslinking to obtain 200 mL of PDMS pre-crosslinking solution, which was evenly coated on the surface of the metal plate. The material flow rate in the forced circulation heat exchanger was set to 2 m / s.

[0059] After running Example 1, Comparative Example 1 and Comparative Example 2 for one month respectively, it was observed whether there was material deposition on the inner wall of the evaporator. The anti-scaling ability was obtained by comparison: Example 1> Comparative Example 1> Comparative Example 2.

Claims

1. A low-temperature and high-efficiency MVR evaporator, characterized in that: The invention comprises a vacuum pump (1), an evaporation tank (2), a filter (3), a forced circulation pump (4), a first forced circulation plate heat exchanger (5), a booster fan (6), a condensate tank (7) and a second forced circulation plate heat exchanger (8), wherein the lower part of the side wall of the evaporation tank (2) and the second forced circulation plate heat exchanger (8) are both provided with an inlet for raw wastewater; wherein: The vacuum pump (1) is installed on the upper part of the side wall of the evaporation tank (2); the evaporation tank (2), the first forced circulation plate heat exchanger (5) and the booster fan (6) are connected in sequence through pipelines to form a circulation loop; a high-concentration wastewater outlet is provided on the first forced circulation plate heat exchanger (5); the bottom of the evaporation tank (2) is connected to the filter (3) and the forced circulation pump (4) in sequence through pipelines, and then the pipelines are connected to the high-concentration wastewater outlet pipeline; the first forced circulation plate heat exchanger (5) is connected to the top of the condensate tank (7) through pipelines, the bottom of the condensate tank (7) is connected to the second forced circulation plate heat exchanger (8) through pipelines, and the second forced circulation plate heat exchanger (8) is connected to the raw wastewater inlet pipeline on the evaporation tank (2) through pipelines; A vibration plate group (9) is installed inside the first forced circulation plate heat exchanger (5) and the second forced circulation plate heat exchanger (8), respectively. The vibration plate group (9) includes an isolation plate (91), a vibration plate (92) and an ordinary plate (93). The vibration plate (92) is located between the isolation plate (91) and the ordinary plate (93). The vibration plate (92) transmits vibration energy to the ordinary plate (93).

2. A low-temperature and high-efficiency MVR evaporator as claimed in claim 1, characterized in that: The vibration plate groups are provided in 1 to 5 groups and are evenly distributed in the first forced circulation plate heat exchanger (5) or the second forced circulation plate heat exchanger (8).

3. A low-temperature and high-efficiency MVR evaporator as claimed in claim 1, characterized in that: The four sides of the isolation plate (91), the vibration plate (92) and the common plate (93) are respectively closed by sealing rings to prevent water from flowing through; the vibration plate (92) is partially hollowed out to form a vibration sheet to drive the transmission of vibration energy between the isolation plate (91) and the common plate (93).

4. A low-temperature and high-efficiency MVR evaporator as claimed in claim 1, characterized in that: The vibration plate (92) operates intermittently through a timer control.

5. A low-temperature and high-efficiency MVR evaporator as claimed in claim 1, characterized in that: The surface of the common plate (93) is coated with a hydrophobic PDMS coating.

6. A low-temperature and high-efficiency MVR evaporator as claimed in claim 1, characterized in that: The material flow rate in the first forced circulation plate heat exchanger (5) or the second forced circulation plate heat exchanger (8) is 1.5 to 2 m / s.

7. A low-temperature and high-efficiency MVR evaporator as claimed in claim 6, characterized in that: The preparation method of the PDMS coating is as follows: Dissolve polydimethylsiloxane in n-hexane, add tetraethyl orthosilicate and dibutyltin laurate, stir and mix evenly, ultrasonically treat for 5 to 20 minutes, and then stand at room temperature for crosslinking for 2 to 6 hours to obtain a PDMS pre-crosslinking solution.

8. A low-temperature and high-efficiency MVR evaporator as claimed in claim 6, characterized in that: The volume amount of the n-hexane is 10-30 mL / g based on the mass of PDMS.

9. A low-temperature and high-efficiency MVR evaporator as claimed in claim 6, characterized in that: The mass ratio of the PDMS, tetraethyl orthosilicate and dibutyltin laurate is 50-100:1-10:

1.

10. A low-temperature and high-efficiency MVR evaporator as claimed in claim 6, characterized in that: The ratio of the amount of the PDMS solution to the area of ​​the ordinary plate is 0.1-0.5 mL / cm 2 .

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