MVR evaporation system

Abstract

The utility model relates to the technical field of separation equipment, in particular to an MVR (Mechanical Vapor Recompression) evaporation system which comprises a heating tower, a jacket arranged outside the heating tower, the heating tower connected with a feeding dead steam preheater, a steam pipeline arranged in the middle of the jacket, a first gas-liquid separator arranged at the lower part of the jacket, and a condensate water tank connected with the bottom of the first gas-liquid separator, the top of the first gas-liquid separator is connected with the upper portion of the feeding dead steam preheater shell side and the upper portion of the jacket, the second gas-liquid separator is arranged on the lower portion of the feeding dead steam preheater shell side, the top of the second gas-liquid separator is connected with the upper portion of the mother liquor dead steam preheater shell side, and the third gas-liquid separator is arranged on the lower portion of the mother liquor dead steam preheater shell side. The bottom of the second gas-liquid separator and the bottom of the third gas-liquid separator are both connected with a condensate water tank, the top of the third gas-liquid separator is connected with a non-condensable gas pipeline, the lower portion of the jacket is connected with a vacuum compression pump, and a self-circulation pipeline is arranged on the vacuum compression pump. According to the utility model, repeated utilization of heat is realized, and energy is saved.

Description

Technical Field

[0001] The utility model belongs to the technical field of separation equipment, and particularly relates to an MVR evaporation system. Background Art

[0002] An MVR evaporator, fully known as a mechanical vapor recompression evaporator, is a highly energy-efficient evaporation device. Its working principle is mainly based on the vapor recompression technology, which reuses the energy of the secondary steam generated during the evaporation process and reduces the demand for external energy.

[0003] The material to be processed is first fed into the preheating section of the evaporator, and through indirect heat exchange with the heat medium, the material is preheated to an appropriate temperature. The preheated material enters the heating chamber of the evaporator. At this time, high-temperature steam is introduced into the heating chamber of the evaporator to heat the material, causing the water in the material to evaporate and form a large amount of secondary steam. The secondary steam is introduced into the compressor. Under the action of the compressor, the pressure and temperature of the secondary steam are increased, and the compressed steam has a higher enthalpy value. The compressed steam is reintroduced into the heating chamber of the evaporator to exchange heat with the material to be processed, transferring the heat energy to the material and enabling it to continue to evaporate. In this way, the heat energy of the originally wasted secondary steam is recovered and utilized, improving the thermal efficiency of the evaporator.

[0004] However, there is still remaining heat after the secondary steam is recycled, and the gas carrying this part of the heat forms non-condensable gas. The currently common treatment method is to cool down the non-condensable gas for discharge, resulting in waste of energy. Summary of the Utility Model

[0005] According to the deficiencies in the above prior art, the technical problem to be solved by the utility model is: to provide an MVR evaporation system that uses the heat in the non-condensable gas for the production process, enables the heat to be fully utilized, and reduces energy waste.

[0006] The technical solution adopted by the utility model to solve its technical problems is:

[0007] The MVR evaporation system described in the present utility model includes a heating tower. A jacket is provided outside the heating tower. The heating tower is connected to a feed waste steam preheater. A steam pipeline is provided in the middle of the jacket. A first gas-liquid separator is provided at the lower part of the jacket. The bottom of the first gas-liquid separator is connected to a condensate water tank. The top of the first gas-liquid separator is respectively connected to the upper part of the shell side of the feed waste steam preheater and the upper part of the jacket. A second gas-liquid separator is provided at the lower part of the shell side of the feed waste steam preheater. The top of the second gas-liquid separator is connected to the upper part of the shell side of the mother liquor waste steam preheater. A third gas-liquid separator is provided at the lower part of the shell side of the mother liquor waste steam preheater. The bottoms of the second gas-liquid separator and the third gas-liquid separator are both connected to the condensate water tank. The top of the third gas-liquid separator is connected to a non-condensable gas pipeline. The lower part of the jacket is connected to a vacuum compression pump. A self-circulation pipeline is provided on the vacuum compression pump. The top of the vacuum compression pump is connected to the middle of the jacket. The top of the condensate water tank is connected to the vacuum compression pump through a pipeline.

[0008] An first-effect separation zone, a second-effect separation zone, a third-effect separation zone and a fourth-effect separation zone are sequentially arranged inside the heating tower. The bottom of the first-effect separation zone is connected to the top of the second-effect separation zone through a pipeline. The bottom of the second-effect separation zone is connected to the top of the third-effect separation zone through a pipeline. The bottom of the third-effect separation zone is connected to the top of the fourth-effect separation zone through a pipeline.

[0009] The top of the first-effect separation zone is connected to the outlet of the feed waste steam preheater. The bottom of the fourth-effect separation zone is connected to a feed and discharge heat exchanger.

[0010] An first-effect discharge pump, a second-effect discharge pump, a third-effect discharge pump and a fourth-effect discharge pump are respectively provided on the pipelines connected to the bottoms of the first-effect separation zone, the second-effect separation zone, the third-effect separation zone and the fourth-effect separation zone.

[0011] A feed heat exchanger is provided between the top of the first-effect separation zone and the outlet of the feed waste steam preheater.

[0012] The feed and discharge heat exchanger is connected to a feed condensate heat exchanger, a feed pipeline and a discharge mother liquor heat exchanger. The upper and lower parts of the discharge mother liquor heat exchanger are respectively connected to a mother liquor pipeline and a discharge pipeline. The discharge mother liquor heat exchanger is connected to the inlet of the mother liquor waste steam preheater. The outlet of the mother liquor waste steam preheater is connected to a mother liquor heat exchanger.

[0013] The bottom of the condensate water tank is connected to the feed condensate heat exchanger. The feed condensate heat exchanger is connected to the inlet of the feed waste steam preheater.

[0014] A transfer pump is provided between the condensate water tank and the feed condensate heat exchanger.

[0015] The top of the vacuum compression pump is connected to the middle of the jacket through a vacuum pipeline. A flow monitor is provided on the vacuum pipeline. A balance valve is provided on the self-circulation pipeline.

[0016] A feed pump is provided on the feed pipeline. A mass flowmeter is provided on the discharge pipeline.

[0017] The beneficial effects of the present utility model are as follows:

[0018] By optimizing the heat transfer in steam, the present utility model realizes the multiple utilization of heat and saves energy. After the secondary steam is reused, there is still some residual heat. The non-condensable gas and condensed water are obtained by separating the secondary steam still carrying heat. Then, the heat in the non-condensable gas is respectively applied to the heating tower, the feed exhaust steam preheater, and the mother liquor exhaust steam preheater, improving the heat utilization efficiency. After that, the used non-condensable gas can be used for evaporation and concentration in the multi-effect falling film evaporator, enabling the full utilization of heat and avoiding energy waste. Brief Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of the present utility model;

[0020] In the figure: 1, heating tower; 2, vacuum compression pump; 3, condensate tank; 4, feed exhaust steam preheater; 5, mother liquor exhaust steam preheater; 6, feed heat exchanger; 7, feed condensate heat exchanger; 8, inlet and outlet heat exchanger; 9, outlet mother liquor heat exchanger; 10, feed pipeline; 11, non-condensable gas pipeline; 12, mother liquor heat exchanger; 13, discharge pipeline; 14, mother liquor pipeline;

[0021] 101, jacket; 102, gas-liquid separator I; 103, steam pipeline; 104, first-effect separation zone; 105, second-effect separation zone; 106, third-effect separation zone; 107, fourth-effect separation zone; 201, self-circulation pipeline; 202, flow monitor; 401, gas-liquid separator II; 501, gas-liquid separator III; 1301, mass flowmeter. Specific Embodiments

[0022] The following further describes the embodiments of the present utility model with reference to the drawings.

[0023] Embodiment 1

[0024] As Figure 1As shown in the figure, the MVR evaporation system of the present utility model includes a heating tower 1. A jacket 101 is arranged outside the heating tower 1. The heating tower 1 is connected to a feed exhaust steam preheater 4. A steam pipeline 103 is arranged in the middle of the jacket 101. A first gas-liquid separator 102 is arranged at the lower part of the jacket 101. The bottom of the first gas-liquid separator 102 is connected to a condensate tank 3. The top of the first gas-liquid separator 102 is respectively connected to the upper part of the shell side of the feed exhaust steam preheater 4 and the upper part of the jacket 101. A second gas-liquid separator 401 is arranged at the lower part of the shell side of the feed exhaust steam preheater 4. The top of the second gas-liquid separator 401 is connected to the upper part of the shell side of a mother liquor exhaust steam preheater 5. A third gas-liquid separator 501 is arranged at the lower part of the shell side of the mother liquor exhaust steam preheater 5. The bottoms of the second gas-liquid separator 401 and the third gas-liquid separator 501 are both connected to the condensate tank 3. The top of the third gas-liquid separator 501 is connected to a non-condensable gas pipeline 11. The lower part of the jacket 101 is connected to a vacuum compression pump 2. A self-circulation pipeline 201 is arranged on the vacuum compression pump 2. The top of the vacuum compression pump 2 is connected to the middle of the jacket 101. The top of the condensate tank 3 is connected to the vacuum compression pump 2 through a pipeline.

[0025] After the high-temperature steam in the jacket 101 undergoes heat exchange, it is compressed and heated by the vacuum compression pump 2 to form secondary steam. The secondary steam is re-transported back to the middle of the jacket 101 for reuse. After the secondary steam is reused, there will still be some residual heat. The non-condensable gas and condensate are separated through the first gas-liquid separator 102. The non-condensable gas can be divided into two parts for reuse. One part is re-transported back to the jacket 101 for heat exchange of the heating tower 1, and the other part is used for preheating the material and heating the mother liquor. The temperature of the used non-condensable gas is 60 - 80 °C, and it can also be used for evaporation and concentration of a multi-effect falling film evaporator, achieving the maximum utilization of heat.

[0026] An first-effect separation zone 104, a second-effect separation zone 105, a third-effect separation zone 106, and a fourth-effect separation zone 107 are sequentially arranged inside the heating tower 1. The bottom of the first-effect separation zone 104 is connected to the top of the second-effect separation zone 105 through a pipeline. The bottom of the second-effect separation zone 105 is connected to the top of the third-effect separation zone 106 through a pipeline. The bottom of the third-effect separation zone 106 is connected to the top of the fourth-effect separation zone 107 through a pipeline.

[0027] The top of the first-effect separation zone 104 is connected to the outlet of the feed exhaust steam preheater 4. The bottom of the fourth-effect separation zone 107 is connected to a feed and discharge heat exchanger 8.

[0028] The feed exhaust steam preheater 4 can preheat the material and increase the temperature of the material.

[0029] On the pipelines connected to the bottoms of the first-effect separation zone 104, the second-effect separation zone 105, the third-effect separation zone 106, and the fourth-effect separation zone 107, a first-effect discharge pump, a second-effect discharge pump, a third-effect discharge pump, and a fourth-effect discharge pump are respectively arranged.

[0030] A feed heat exchanger 6 is provided between the top of the first-effect separation zone and the outlet of the feed flash steam preheater.

[0031] The feed heat exchanger 6 uses 90°C hot water to reheat the preheated material, raising the material temperature to an appropriate temperature and improving work efficiency.

[0032] The inlet and outlet heat exchanger 8 is connected to a feed condensate heat exchanger 7, a feed pipeline 10, and an outlet mother liquor heat exchanger 9. The upper and lower parts of the outlet mother liquor heat exchanger 9 are respectively connected to a mother liquor pipeline 14 and an outlet pipeline 13. The outlet mother liquor heat exchanger 9 is connected to the inlet of the mother liquor flash steam preheater 5, and the outlet of the mother liquor flash steam preheater 5 is connected to a mother liquor heat exchanger 12.

[0033] The bottom of the condensate tank 3 is connected to the feed condensate heat exchanger 7, and the feed condensate heat exchanger 7 is connected to the inlet of the feed flash steam preheater 4.

[0034] The above settings enable the material to exchange heat with the evaporated material first during transportation, then with the condensate, and finally enter the feed flash steam preheater 4 for preheating. Multiple heat exchanges can gradually increase the temperature of the material, improve work efficiency, realize the utilization of energy, and avoid waste.

[0035] The mother liquor heat exchanger 12 uses 90°C hot water to reheat the mother liquor.

[0036] A transfer pump is provided between the condensate tank 3 and the feed condensate heat exchanger 7.

[0037] The top of the vacuum compression pump 2 is connected to the middle of the jacket 101 through a vacuum pipeline. A flow monitor 202 is provided on the vacuum pipeline, and a balance valve is provided on the self-circulation pipeline 201.

[0038] When the vacuum compression pump 2 compresses and transports steam, it is prone to vibration due to unstable flow. The flow monitor 202 can monitor the secondary steam compressed and transported by the vacuum compression pump 2. When the flow of the flow monitor 202 is unstable, the balance valve is opened to enable the vacuum compression pump 2 to perform self-circulation, continuously compressing and accumulating the flow of the secondary steam to make the flow of the transported secondary steam uniform, reduce vibration, and prevent damage to the vacuum compression pump 2.

[0039] A feed pump is provided on the feed pipeline 10, and a mass flowmeter 1301 is provided on the outlet pipeline 13.

[0040] Working principle and process:

[0041] When the material evaporates, the material is continuously transported by a material pump. The material undergoes multiple heat exchanges through the feed and discharge heat exchanger 8, the condensate heat exchanger 7, the feed exhaust steam preheater 4, and the feed heat exchanger 6, and then enters the heating tower 1 for multi-effect evaporation after reaching an appropriate temperature. After the steam in the jacket 101 undergoes heat exchange, it enters the vacuum compression pump 2 from the lower part of the jacket 101, is recompressed and heated up, and then transported back to the middle part of the jacket 101 for secondary heat exchange. The steam after the secondary heat exchange separates non-condensable gas and condensate from the gas-liquid separator 102 at the lower part of the jacket 101. The condensate is transported to the condensate tank 3. The non-condensable gas is divided into two parts. One part is transported to the upper part of the jacket 101 for heat exchange again, and the other part is used for preheating the raw material and then for heating the mother liquor. During this process, high-temperature steam is supplemented into the jacket 101 through the steam pipeline 103 to ensure stable heat in the jacket 101. There is still some residual heat in the used non-condensable gas, which can be used for heat exchange in the multi-effect falling film evaporator. After multi-effect heating evaporation, the material can be applied to various processing procedures.

Claims

1. An MVR evaporation system, comprising a heating tower (1), a jacket (101) is arranged outside the heating tower (1), and the heating tower (1) is connected to a feed exhaust steam preheater (4), characterized in that, In the middle of the jacket (101), there is a steam pipeline (103). At the lower part of the jacket (101), there is a first-stage gas-liquid separator (102). The bottom of the first-stage gas-liquid separator (102) is connected to a condensate tank (3). The top of the first-stage gas-liquid separator (102) is respectively connected to the upper part of the shell side of the feed waste steam preheater (4) and the upper part of the jacket (101). At the lower part of the shell side of the feed waste steam preheater (4), there is a second-stage gas-liquid separator (401). The top of the second-stage gas-liquid separator (401) is connected to the upper part of the shell side of the mother liquor waste steam preheater (5). At the lower part of the shell side of the mother liquor waste steam preheater (5), there is a third-stage gas-liquid separator (501). The bottoms of the second-stage gas-liquid separator (401) and the third-stage gas-liquid separator (501) are both connected to the condensate tank (3). The top of the third-stage gas-liquid separator (501) is connected to a non-condensable gas pipeline (11). The lower part of the jacket (101) is connected to a vacuum compression pump (2). A self-circulation pipeline (201) is arranged on the vacuum compression pump (2). The top of the vacuum compression pump (2) is connected to the middle part of the jacket (101). The top of the condensate tank (3) is connected to the vacuum compression pump (2) through a pipeline.

2. The MVR evaporation system according to claim 1, wherein Inside the heating tower (1), there are successively a first-effect separation zone (104), a second-effect separation zone (105), a third-effect separation zone (106), and a fourth-effect separation zone (107). The bottom of the first-effect separation zone (104) is connected to the top of the second-effect separation zone (105) through a pipeline. The bottom of the second-effect separation zone (105) is connected to the top of the third-effect separation zone (106) through a pipeline. The bottom of the third-effect separation zone (106) is connected to the top of the fourth-effect separation zone (107) through a pipeline.

3. The MVR evaporation system according to claim 2, wherein, The top of the first-effect separation zone (104) is connected to the outlet of the feed waste steam preheater (4). The bottom of the fourth-effect separation zone (107) is connected to an inlet-outlet heat exchanger (8).

4. The MVR evaporation system according to claim 3, wherein On the pipelines connected to the bottoms of the first-effect separation zone (104), the second-effect separation zone (105), the third-effect separation zone (106), and the fourth-effect separation zone (107), there are respectively a first-effect discharge pump, a second-effect discharge pump, a third-effect discharge pump, and a fourth-effect discharge pump.

5. The MVR evaporation system according to claim 3, characterized in that, There is a feed heat exchanger (6) between the top of the first-effect separation zone (104) and the outlet of the feed waste steam preheater (4).

6. The MVR evaporation system according to claim 3, wherein, The inlet-outlet heat exchanger (8) is connected to a feed condensate heat exchanger (7), a feed pipeline (10), and a discharge mother liquor heat exchanger (9). The upper and lower parts of the discharge mother liquor heat exchanger (9) are respectively connected to a mother liquor pipeline (14) and a discharge pipeline (13). The discharge mother liquor heat exchanger (9) is connected to the inlet of the mother liquor waste steam preheater (5). The outlet of the mother liquor waste steam preheater (5) is connected to a mother liquor heat exchanger (12).

7. The MVR evaporation system according to claim 6, characterized in that, The bottom of the condensate tank (3) is connected to the feed condensate heat exchanger (7). The feed condensate heat exchanger (7) is connected to the inlet of the feed waste steam preheater (4).

8. The MVR evaporation system according to claim 7, characterized in that, There is a transfer pump between the condensate tank (3) and the feed condensate heat exchanger (7).

9. The MVR evaporation system according to claim 1, wherein, The top of the vacuum compression pump (2) is connected to the middle part of the jacket (101) through a vacuum pipeline. A flow monitor (202) is arranged on the vacuum pipeline. A balance valve is arranged on the self-circulation pipeline (201).

10. The MVR evaporation system according to claim 6, wherein, A feed pump is provided on the feed pipe (10), and a mass flowmeter (1301) is provided on the discharge pipe (13).

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