MVR (mechanical vapor recompression) evaporation system for concentrating sorbitol liquid

Abstract

The utility model belongs to the technical field of sugar alcohol preparation equipment, and relates to an MVR (mechanical vapor recompression) evaporation system for concentrating sorbitol liquid, which comprises a stock solution tank and a post-evaporation tank. And the sorbitol is sequentially evaporated by a first-effect heating chamber and a second-effect heating chamber, and the obtained sorbitol concentrated solution enters a rear evaporation tank. After being heated by a centrifugal compressor, first-effect steam obtained by separation in the first-effect separation chamber returns to the first-effect heating chamber again to be used as a heat source for evaporating sorbitol liquid in the first-effect heating chamber. And second-effect steam obtained by separation in the second-effect separation chamber is heated through the screw compressor and then returns to the second-effect heating chamber to be used as a heat source for evaporating the sorbitol liquid in the second-effect heating chamber. According to the utility model, the combination of the centrifugal compressor and the screw compressor is adopted in the MVR evaporator, and a part of steam heat source is changed into electricity, so that the concentration and evaporation cost of sorbitol liquid is reduced, and the economic benefit is improved.

Description

Technical Field

[0001] This utility model belongs to the technical field of sugar alcohol preparation equipment, and specifically relates to an MVR evaporation system for concentrating sorbitol solution. Background Technology

[0002] Due to the high boiling point of sorbitol solution, existing sorbitol evaporation and concentration technologies mostly employ multi-effect evaporation followed by single-effect evaporation to obtain molten sorbitol for subsequent production of crystalline sorbitol. However, this evaporation and concentration technology uses steam as a heat source, resulting in high production costs. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide an MVR evaporation system for concentrating sorbitol liquid. The MVR evaporator replaces the multi-effect evaporator, and the MVR evaporator uses a combination of centrifugal compressor and screw compressor to obtain a high-concentration sorbitol liquid concentrate, thereby reducing the concentration and evaporation cost of sorbitol liquid and improving economic efficiency.

[0004] This invention is implemented as follows: An MVR evaporation system for concentrating sorbitol solution is provided, comprising a raw material tank for storing sorbitol solution and a post-evaporation tank for storing concentrated sorbitol solution. The outlet of the raw material tank is connected to the raw material inlet of the first-effect heating chamber via a raw material pipeline. A preheater is connected to the raw material pipeline. The outlet of the first-effect heating chamber is connected to the raw material inlet of the second-effect heating chamber via an intermediate pipeline. The outlet of the second-effect heating chamber is connected to the inlet of the post-evaporation tank via an outlet pipeline. The steam outlet of the first-effect heating chamber is connected to the first-effect separation chamber. The steam outlet of the first-effect separation chamber is connected to the inlet of a centrifugal compressor via a first-effect exhaust pipe. The outlet of the centrifugal compressor is connected to the heat source inlet of the first-effect heating chamber via a first-effect intake pipe. The steam outlet of the second-effect heating chamber is connected to the second-effect separation chamber. The steam outlet of the second-effect separation chamber is connected to the inlet of a screw compressor via a second-effect exhaust pipe. The outlet of the screw compressor is connected to the heat source inlet of the second-effect heating chamber via a second-effect intake pipe. The discharge port of the first-effect separation chamber is connected to the return port of the first-effect heating chamber, and the discharge port of the second-effect separation chamber is connected to the return port of the second-effect heating chamber. The non-condensable gas outlet of the first-effect heating chamber is connected to the inlet of the vacuum pump through a non-condensable gas pipeline, and the non-condensable gas outlet of the second-effect heating chamber is also connected to the inlet of the vacuum pump through a non-condensable gas pipeline. The heat source end of the surface cooler is connected to the non-condensable gas pipeline. The condensate outlet of the first-effect heating chamber is connected to the inlet of the condensate tank through a first-effect condensate pipeline, the condensate outlet of the second-effect heating chamber is connected to the inlet of the condensate tank through a second-effect condensate pipeline, the condensate outlet of the preheater is connected to the inlet of the condensate tank through a preheater condensate pipeline, and the condensate outlet of the surface cooler is connected to the inlet of the condensate tank through a surface cooler condensate pipeline.

[0005] Furthermore, three heating pipes are installed in the first-effect heating chamber. The outlet of the first heating pipe is connected to the inlet of the second heating pipe through an external first-stage discharge pipe. The outlet of the second heating pipe is connected to the inlet of the third heating pipe through an external second-stage discharge pipe. The third discharge outlet is connected to the middle pipe.

[0006] Furthermore, a discharge pump is installed on the first discharge pipe, a second discharge pump is installed on the second discharge pipe, and a third discharge pump is installed on the intermediate pipe.

[0007] Furthermore, a first-effect discharge regulating valve is installed on the intermediate pipeline between the first-effect heating chamber and the three-stage discharge pump, and a first signal interlock control line is installed between the first-effect discharge regulating valve and the first-effect heating chamber.

[0008] Furthermore, the raw material pipeline between the raw liquid tank and the preheater is sequentially connected to the cold source end of the inlet and outlet heat exchanger and the heat source end of the condensate heat exchanger. The discharge pipeline is connected to the heat source end of the inlet and outlet heat exchanger, and the outlet of the condensate tank is connected to the cold source end of the condensate heat exchanger through the condensate outlet pipeline.

[0009] Furthermore, a feed pump is installed on the raw material pipeline, and a discharge pump is installed on the discharge pipeline. The feed pump and discharge pump are respectively located at the front end of the feed and discharge heat exchangers. A feed valve is also installed on the raw material pipeline between the feed pump and the feed and discharge heat exchangers. A feed regulating valve is installed on the raw material pipeline between the condensate heat exchanger and the preheater. A discharge pneumatic valve is installed on the discharge pipeline between the feed and discharge heat exchangers and the evaporation tank.

[0010] Furthermore, a water pump is installed on the first-effect condensate pipe, two water pumps are installed on the second-effect condensate pipe, an outlet pump is installed on the condensate outlet pipe, a cold water regulating valve is installed on the condensate outlet pipe of the condensate tank and the outlet pump, and a second signal interlock control line is installed between the condensate tank and the cold water regulating valve.

[0011] Furthermore, a reflux pipe is provided between the discharge pipe and the raw liquid tank. One end of the reflux pipe is connected to the reflux port of the raw liquid tank, and the other end of the reflux pipe is connected to the discharge pipe between the inlet / outlet heat exchanger and the evaporation tank. A reflux pneumatic valve is provided on the reflux pipe.

[0012] Furthermore, a first steam port is provided on the preheater, which is connected to a first steam pipe, and a first steam regulating valve is provided on the first steam pipe; a second steam port is provided on the centrifugal compressor, and a second steam pipe is provided between the second steam port and the first steam pipe for mutual connection.

[0013] Furthermore, a supplementary steam pipe is provided between the first-effect exhaust pipe and the heat source inlet of the second-effect heating chamber, and a supplementary steam valve is provided on the supplementary steam pipe.

[0014] Compared with existing technologies, the MVR evaporation system for concentrating sorbitol liquid of this invention includes a raw liquid tank and a post-evaporation tank. The sorbitol liquid to be concentrated, stored in the raw liquid tank, is preheated sequentially through an inlet / outlet heat exchanger, a condensate heat exchanger, and a preheater. It is then evaporated sequentially in a first-effect heating chamber and a second-effect heating chamber to obtain concentrated sorbitol liquid, which is temporarily stored in the post-evaporation tank through an outlet pipe. The first-effect vapor separated in the first-effect separation chamber is reheated by a centrifugal compressor and returned to the first-effect heating chamber through the first-effect inlet pipe, serving as a heat source for evaporating the sorbitol liquid therein. The second-effect vapor separated in the second-effect separation chamber is reheated by a screw compressor and returned to the second-effect heating chamber through the second-effect inlet pipe, also serving as a heat source for evaporating the sorbitol liquid therein. The non-condensable gases from the first and second-effect heating chambers are connected to a vacuum pump through non-condensable gas pipes, which are also connected to the heat source end of a surface cooler. The condensate from the first-effect heating chamber, the second-effect heating chamber, the preheater, and the surface cooler is connected to the inlet of the condensate tank via pipelines. The outlet of the condensate tank is connected to the cold source end of the condensate heat exchanger via a condensate outlet pipe. This invention employs a combination of a centrifugal compressor and a screw compressor in the MVR evaporator, converting part of the steam heat source into electricity, reducing the concentration and evaporation cost of sorbitol solution, and improving economic efficiency. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a preferred embodiment of the MVR evaporation system for concentrating sorbitol solution according to the present invention.

[0016] The symbols in the image are as follows:

[0017] 1. Raw material tank; 2. Evaporation tank; 3. First-effect heating chamber; 4. Second-effect heating chamber; 5. Raw material pipeline; 6. Inlet and outlet heat exchangers; 7. Condensate heat exchanger; 8. Preheater; 9. Intermediate pipeline; 10. Discharge pipeline; 11. First-effect separation chamber; 12. First-effect exhaust pipeline; 13. Centrifugal compressor; 14. First-effect intake pipeline; 15. Second-effect separation chamber; 16. Second-effect exhaust pipeline; 17. Screw compressor; 18. Second-effect intake pipeline; 19. Non-condensable gas pipeline; 20. Vacuum pump; 21. Surface cooler; 22. Circulating cooling water pipe; 23. First-effect condensate pipeline; 24. Second-effect condensate pipeline; 25. Preheater condensate pipeline; 26. Surface cooler condensate pipeline; 27. Condensate tank. 28. Condensate outlet pipe; 29. ​​First stage discharge pipe; 30. Second stage discharge pipe; 31. First stage discharge pump; 32. Second stage discharge pump; 33. Third stage discharge pump; 34. First-stage discharge regulating valve; 35. Feed pump; 36. Discharge pump; 37. Feed valve; 38. Feed regulating valve; 39. First stage water pump; 40. Second stage water pump; 41. Discharge pump; 42. Cold water regulating valve; 43. Return pipe; 44. Return pneumatic valve; 45. First steam pipe; 46. First steam regulating valve; 47. Second steam pipe; 48. Steam replenishment pipe; 49. Steam replenishment valve; 50. First-stage return pipe; 51. Second-stage return pipe; 52. Discharge pneumatic valve; 53. Second steam regulating valve. Detailed Implementation

[0018] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0019] Please refer to Figure 1 As shown, a preferred embodiment of the MVR evaporation system for concentrating sorbitol solution according to this invention includes a stock tank 1 for storing sorbitol solution, a post-evaporation tank 2 for storing concentrated sorbitol solution, a first-effect heating chamber 3 for evaporating the sorbitol solution, and a second-effect heating chamber 4. The arrowed lines in the figure indicate the flow direction of materials in the system, including sorbitol solution, vapor, steam, condensate, and non-condensable gases.

[0020] The outlet of the raw liquid tank 1 is connected to the raw material inlet of the first-effect heating chamber 3 via the raw material pipeline 5. The raw material pipeline 5 is sequentially connected to the cold source end of the inlet / outlet heat exchanger 6, the heat source end of the condensate heat exchanger 7, and the cold source end of the preheater 8. The outlet of the first-effect heating chamber 3 is connected to the raw material inlet of the second-effect heating chamber 4 via the intermediate pipeline 9. The outlet of the second-effect heating chamber 4 is connected to the inlet of the evaporation tank 2 via the outlet pipeline 10. The outlet pipeline 10 is connected to the heat source end of the inlet / outlet heat exchanger 6.

[0021] The steam outlet of the first-effect heating chamber 3 is connected to the first-effect separation chamber 11. The steam outlet of the first-effect separation chamber 11 is connected to the inlet of the centrifugal compressor 13 via the first-effect exhaust pipe 12. The outlet of the centrifugal compressor 13 is connected to the heat source inlet of the first-effect heating chamber 4 via the first-effect intake pipe 14. The steam outlet of the second-effect heating chamber 4 is connected to the second-effect separation chamber 15. The steam outlet of the second-effect separation chamber 15 is connected to the inlet of the screw compressor 17 via the second-effect exhaust pipe 16. The outlet of the screw compressor 17 is connected to the heat source inlet of the second-effect heating chamber 4 via the second-effect intake pipe 18. The discharge port of the first-effect separation chamber 11 is connected to the return port of the first-effect heating chamber 3 via the first-effect return pipe 50. The discharge port of the second-effect separation chamber 15 is connected to the return port of the second-effect heating chamber 4 via the second-effect return pipe 51.

[0022] The non-condensable gas outlet of the first-effect heating chamber 3 is connected to the inlet of the vacuum pump 20 through the non-condensable gas pipe 19. The non-condensable gas outlet of the second-effect heating chamber 4 is also connected to the inlet of the vacuum pump 20 through the non-condensable gas pipe 19. The heat source end of the surface cooler 21 is connected to the non-condensable gas pipe 19, and the cold source end of the surface cooler 21 is connected to the circulating cooling water pipe 22.

[0023] The condensate outlet of the first-effect heating chamber 3 is connected to the inlet of the condensate tank 27 via the first-effect condensate pipe 23. The condensate outlet of the second-effect heating chamber 4 is connected to the inlet of the condensate tank 27 via the second-effect condensate pipe 24. The condensate outlet of the preheater 8 is connected to the inlet of the condensate tank 27 via the preheater condensate pipe 25. The condensate outlet of the surface cooler is connected to the inlet of the condensate tank 27 via the surface cooler condensate pipe 26. The outlet of the condensate tank 27 is connected to the cold source end of the condensate heat exchanger 7 via the condensate outlet pipe 28.

[0024] Three heating pipes are installed in the first-effect heating chamber 3. The outlet of the first heating pipe is connected to the inlet of the second heating pipe through an external first-stage discharge pipe 29. The outlet of the second heating pipe is connected to the inlet of the third heating pipe through an external second-stage discharge pipe 30. The outlet of the third heating pipe is connected to the middle pipe 9.

[0025] A discharge pump 31 is installed on the first discharge pipe 29, a second discharge pump 32 is installed on the second discharge pipe 30, and a third discharge pump 33 is installed on the middle pipe 9.

[0026] A first-effect discharge regulating valve 34 is installed on the intermediate pipe 9 between the first-effect heating chamber 3 and the three-stage discharge pump 33, and a first signal interlock control line is installed between the first-effect discharge regulating valve 34 and the first-effect heating chamber 3.

[0027] A feed pump 35 is installed on the raw material pipeline 5, and a discharge pump 36 is installed on the discharge pipeline 10. The feed pump 35 and the discharge pump 36 are respectively located at the front end of the feed and discharge heat exchangers 6. A feed valve 37 is also installed on the raw material pipeline 5 between the feed pump 35 and the feed and discharge heat exchangers 6, and a feed regulating valve 38 is installed on the raw material pipeline 5 between the condensate heat exchanger 7 and the preheater 8. A discharge pneumatic valve 52 is installed on the discharge pipeline 10 between the feed and discharge heat exchangers 6 and the evaporation tank 2.

[0028] A water pump 39 is installed on the first-effect condensate pipe 23, a second-effect condensate pipe 24 is installed with two water pumps 40, and a water outlet pump 41 is installed on the condensate outlet pipe 28. A cold water regulating valve 42 is installed on the condensate outlet pipe 28 between the condensate tank 27 and the water outlet pump 41, and a second signal interlock control line is installed between the condensate tank 27 and the cold water regulating valve 42.

[0029] A return pipe 43 is provided between the discharge pipe 10 and the raw liquid tank 1. One end of the return pipe 43 is connected to the return port of the raw liquid tank 1, and the other end of the return pipe 43 is connected to the discharge pipe 10 between the inlet / outlet heat exchanger 6 and the evaporation tank 2. A return pneumatic valve 44 is provided on the return pipe 43.

[0030] A first steam port is provided on the preheater 8, and the first steam port is connected to the first steam pipe 45. A first steam regulating valve 46 is provided on the first steam pipe 45.

[0031] A second steam port is provided on the centrifugal compressor 13, and a second steam pipe 47 is provided between the second steam port and the first steam pipe 45 to connect them. A second steam regulating valve 53 is provided on the second steam pipe 47.

[0032] A supplementary steam pipe 48 is provided between the first-effect exhaust pipe 12 and the heat source inlet of the second-effect heating chamber 4, and a supplementary steam valve 49 is provided on the supplementary steam pipe 48.

[0033] In the MVR evaporation system of this invention, the flow path of the sorbitol solution is as follows: the low-concentration sorbitol solution to be evaporated and concentrated enters the raw material tank 1 for temporary storage through the liquid delivery pipeline. The sorbitol solution flows sequentially through the raw material pipeline through the feed pump 35, feed valve 37, feed and discharge heat exchanger 6, condensate heat exchanger 7, feed regulating valve, and preheater 8 for preheating, and then enters the first-effect heating chamber 3 for three-stage heating and evaporation. The sorbitol solution undergoes multi-stage heating and evaporation through the externally installed first-stage discharge pipeline 29, first-stage discharge pump 31, second-stage discharge pipeline 30, and second-stage discharge pump 32. The vapor after evaporation in the first-effect heating chamber 3 enters the first-effect separation chamber 11 and is separated into first-effect vapor and sorbitol solution. The sorbitol solution returns to the first-effect heating chamber 3 through the first-effect return pipeline 50 for reuse, while the first-effect vapor enters the vapor flow path.

[0034] The heated and evaporated sorbitol solution then enters the second-effect heating chamber 4 through the intermediate pipe 9 and the three-stage discharge pump 33 for further heating and evaporation, yielding a high-concentration sorbitol concentrate. The vapor from the second-effect heating chamber 4 enters the second-effect separation chamber 15 and is separated into second-effect vapor and sorbitol solution. The sorbitol solution returns to the second-effect heating chamber 4 through the second-effect return pipe 51 for reuse, while the second-effect vapor enters the vapor flow path. The high-concentration sorbitol concentrate then flows through the discharge pipe 10, sequentially passing through the inlet / outlet heat exchanger 6 and the discharge pneumatic valve 52, before entering the post-evaporation tank 2 for storage.

[0035] The high-temperature sorbitol concentrate and the low-temperature sorbitol solution exchange heat as they flow through the feed and discharge heat exchangers 6, respectively.

[0036] In the MVR evaporation system of this invention, the steam flow path is as follows: First-effect steam separated in the first-effect separation chamber 11 enters the centrifugal compressor 13 through the first-effect outlet pipe 12. After compression, the temperature of the first-effect steam increases due to compression. The heated first-effect steam then enters the first-effect heating chamber 3 through the first-effect inlet pipe 14 to heat and evaporate the sorbitol liquid flowing through the first-effect heating chamber 3. Second-effect steam separated in the second-effect separation chamber 15 enters the screw compressor through the second-effect outlet pipe 16. After compression, the temperature of the second-effect steam increases due to compression. The heated second-effect steam then enters the second-effect heating chamber 4 through the second-effect inlet pipe 18 to heat and evaporate the sorbitol liquid flowing through the second-effect heating chamber 4. When the heat source temperature of the second-effect heating chamber 4 is low, the first-effect steam in the first-effect outlet pipe 12 directly enters the second-effect heating chamber 4 through the supplementary steam pipe 48.

[0037] In addition, external steam provides a heat source for the preheater 8 through the first steam pipe 45 and the first steam regulating valve 46, and the condensate generated by the steam precooling enters the condensate flow path. Another part of the steam enters the centrifugal compressor 13 through the second steam pipe 47 connected to the first steam pipe 45, supplementing the centrifugal compressor 13 with steam.

[0038] In the MVR evaporation system of this invention, the flow path of the condensate is as follows: the condensate generated in the first-effect heating chamber 3 enters the condensate tank 27 through the first-effect condensate pipe 23 and a first-stage water pump 39; the condensate generated in the second-effect heating chamber 4 enters the condensate tank 27 through the second-effect condensate pipe 24 and a second-stage water pump 40; the condensate generated in the preheater 8 enters the condensate tank 27 through the preheater condensate pipe 25; and the condensate generated in the surface cooler 21 enters the condensate tank 27 through the surface cooler condensate pipe. The condensate stored in the condensate tank 27 enters the cold source end of the condensate heat exchanger 7 through the condensate outlet pipe 28 and the outlet pump 41, where it exchanges heat with the sorbitol solution flowing through the condensate heat exchanger 7.

[0039] In the MVR evaporation system of this invention, the flow path of the non-condensable gas is as follows: the non-condensable gas generated in the first-effect heating chamber 3 and the second-effect heating chamber 4 enters the vacuum pump 20 through the non-condensable gas pipe 19 and the heat source end of the surface cooler 21, respectively. The vacuum pump 20 extracts the non-condensable gas generated in the first-effect heating chamber 3 and the second-effect heating chamber 4, improving the heat exchange efficiency of the first-effect heating chamber 3 and the second-effect heating chamber 4; at the same time, it keeps the first-effect heating chamber 3 and the second-effect heating chamber 4 under negative pressure, so that the sorbitol liquid is heated and evaporated under vacuum conditions, improving the evaporation efficiency. The non-condensable gas referred to in this invention includes tail gases such as nitrogen, oxygen, and carbon dioxide.

[0040] The following specific embodiments further illustrate the effectiveness of the MVR evaporation system for concentrating sorbitol solution according to this invention.

[0041] Example 1

[0042] In this embodiment, the solids content of the sorbitol solution to be concentrated is 35%, and it is stored in the stock solution tank 1. After the vacuum pump 20 is turned on, the vacuum degree is controlled at -0.06~-0.07 MPa. The first-effect vapor separated in the first-effect separation chamber 11 has a temperature of 70~80℃. After being compressed and heated to 90~100℃ by the centrifugal compressor 13, the first-effect vapor is sent back to the first-effect heating chamber 3 for the evaporation and concentration of the sorbitol solution. The second-effect vapor separated in the second-effect heating chamber 4 has a temperature of 70~80℃. After being heated to 100~110℃ by the screw compressor 17, the second-effect vapor is sent back to the second-effect heating chamber 4 for the evaporation and concentration of the sorbitol solution. Finally, the solids content of the sorbitol concentrate obtained is 84%.

[0043] In this embodiment, the electricity consumption is 87.71 kWh / ton, the steam consumption is 0.176 tons / ton, the electricity price is 0.8 yuan / kWh, and the steam price is 165 yuan / ton, resulting in a total cost of 99.21 yuan / ton per unit of electricity consumption.

[0044] Example 2

[0045] The steps and conditions in this embodiment are the same as in Example 1, and will not be repeated here. Finally, the sorbitol concentrate was found to have a solids content of 85%.

[0046] In this embodiment, the electricity consumption is 88.41 kWh / ton, the steam consumption is 0.165 tons / ton, the electricity price is calculated at 0.8 yuan / kWh, and the steam price is calculated at 165 yuan / ton, resulting in a total cost of 97.95 yuan / ton per unit of electricity consumption.

[0047] Example 3

[0048] The steps and conditions in this embodiment are the same as in Example 1, and will not be repeated here. Finally, the sorbitol concentrate was found to have a solids content of 86%.

[0049] In this embodiment, the electricity consumption is 89.10 kWh / ton, the steam consumption is 0.154 tons / ton, the electricity price is 0.8 yuan / kWh, and the steam price is 165 yuan / ton, resulting in a total cost of 96.69 yuan / ton per unit of electricity consumption.

[0050] Comparative Example

[0051] The sorbitol solution to be concentrated in this comparative example had a solids content of 35% and was stored in the pre-evaporation tank. The sorbitol solution sequentially passed through a feed pump → plate heat exchanger → preheater → first-effect heating chamber → first-effect discharge pump → second-effect heating chamber → second-effect discharge pump → third-effect heating chamber → third-effect discharge pump → post-evaporation tank, yielding a high-concentration sorbitol concentrate. The heat source for the first-effect heating chamber was steam, and secondary steam was used by the heat sources for the first, second, and third effects. Finally, the sorbitol concentrate obtained had a solids content of 86%.

[0052] In this comparative example, the steam consumption per ton is 0.6623 tons, and the steam cost is calculated at 165 yuan per ton, resulting in a total cost of 109.23 yuan per ton.

[0053] Based on the cost data from Examples 1-3 and the comparative examples above, the cost of using the MVR evaporation system of this invention for evaporating and concentrating sorbitol solution is significantly lower than that of existing multi-effect heating evaporation and concentration methods. Furthermore, the higher the solids content of the concentrated sorbitol solution, the lower the cost. This invention reduces the cost of sorbitol solution concentration and evaporation, improves economic efficiency, and achieves the expected results.

[0054] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An MVR evaporation system for concentrating sorbitol solution, comprising a stock tank for storing sorbitol solution and a post-evaporation tank for storing sorbitol concentrate, characterized in that, The discharge port of the raw liquid tank is connected to the raw material inlet of the first-effect heating chamber through the raw material pipeline. A preheater is connected to the raw material pipeline. The discharge port of the first-effect heating chamber is connected to the raw material inlet of the second-effect heating chamber through the intermediate pipeline. The discharge port of the second-effect heating chamber is connected to the feed port of the evaporation tank through the discharge pipeline. The steam outlet of the first-effect heating chamber is connected to the first-effect separation chamber. The steam outlet of the first-effect separation chamber is connected to the inlet of the centrifugal compressor through the first-effect exhaust pipe. The outlet of the centrifugal compressor is connected to the heat source inlet of the first-effect heating chamber through the first-effect intake pipe. The steam outlet of the second-effect heating chamber is connected to the second-effect separation chamber. The steam outlet of the second-effect separation chamber is connected to the inlet of the screw compressor through the second-effect exhaust pipe. The outlet of the screw compressor is connected to the heat source inlet of the second-effect heating chamber through the second-effect intake pipe. The discharge port of the first-effect separation chamber is connected to the return port of the first-effect heating chamber. The discharge port of the second-effect separation chamber is connected to the return port of the second-effect heating chamber. The non-condensable gas outlet of the first-effect heating chamber is connected to the inlet of the vacuum pump through a non-condensable gas pipeline. The non-condensable gas outlet of the second-effect heating chamber is also connected to the inlet of the vacuum pump through a non-condensable gas pipeline. The heat source end of the surface cooler is connected to the non-condensable gas pipeline. The condensate outlet of the first-effect heating chamber is connected to the inlet of the condensate tank through the first-effect condensate pipe; the condensate outlet of the second-effect heating chamber is connected to the inlet of the condensate tank through the second-effect condensate pipe; the condensate outlet of the preheater is connected to the inlet of the condensate tank through the preheater condensate pipe; and the condensate outlet of the surface cooler is connected to the inlet of the condensate tank through the surface cooler condensate pipe.

2. The MVR evaporation system for concentrating sorbitol solution as described in claim 1, characterized in that, Three heating pipes are installed in the first-effect heating chamber. The outlet of the first heating pipe is connected to the inlet of the second heating pipe through an external first-stage discharge pipe. The outlet of the second heating pipe is connected to the inlet of the third heating pipe through an external second-stage discharge pipe. The third discharge outlet is connected to the middle pipe.

3. The MVR evaporation system for concentrating sorbitol solution as described in claim 2, characterized in that, A discharge pump is installed on one section of the discharge pipe, a second discharge pump is installed on the second section of the discharge pipe, and a third discharge pump is installed on the middle pipe.

4. The MVR evaporation system for concentrating sorbitol solution as described in claim 3, characterized in that, A first-effect discharge regulating valve is installed on the intermediate pipeline between the first-effect heating chamber and the three-stage discharge pump, and a first signal interlock control line is installed between the first-effect discharge regulating valve and the first-effect heating chamber.

5. The MVR evaporation system for concentrating sorbitol solution as described in claim 1, characterized in that, The raw material pipeline between the raw liquid tank and the preheater is also connected in sequence to the cold source end of the inlet and outlet heat exchanger and the heat source end of the condensate heat exchanger. The discharge pipeline is connected to the heat source end of the inlet and outlet heat exchanger, and the outlet of the condensate tank is connected to the cold source end of the condensate heat exchanger through the condensate outlet pipeline.

6. The MVR evaporation system for concentrating sorbitol solution as described in claim 5, characterized in that, A feed pump is installed on the raw material pipeline, and a discharge pump is installed on the discharge pipeline. The feed pump and discharge pump are respectively located at the front end of the feed and discharge heat exchangers. A feed valve is also installed on the raw material pipeline between the feed pump and the feed and discharge heat exchangers. A feed regulating valve is installed on the raw material pipeline between the condensate heat exchanger and the preheater. A discharge pneumatic valve is installed on the discharge pipeline between the feed and discharge heat exchangers and the evaporation tank.

7. The MVR evaporation system for concentrating sorbitol solution as described in claim 5, characterized in that, A water pump is installed on the first-effect condensate pipe, two water pumps are installed on the second-effect condensate pipe, a water outlet pump is installed on the condensate outlet pipe, a cold water regulating valve is installed on the condensate outlet pipe between the condensate tank and the water outlet pump, and a second signal interlock control line is installed between the condensate tank and the cold water regulating valve.

8. The MVR evaporation system for concentrating sorbitol solution as described in claim 5, characterized in that, A reflux pipe is provided between the discharge pipe and the raw liquid tank. One end of the reflux pipe is connected to the reflux port of the raw liquid tank, and the other end of the reflux pipe is connected to the discharge pipe between the inlet and outlet heat exchanger and the evaporation tank. A reflux pneumatic valve is provided on the reflux pipe.

9. The MVR evaporation system for concentrating sorbitol solution as described in claim 1, characterized in that, A first steam port is provided on the preheater, and the first steam port is connected to a first steam pipe. A first steam regulating valve is provided on the first steam pipe. A second steam port is provided on the centrifugal compressor, and a second steam pipe is provided between the second steam port and the first steam pipe to connect them.

10. The MVR evaporation system for concentrating sorbitol solution as described in claim 1, characterized in that, A supplementary steam pipe is installed between the first-effect exhaust pipe and the heat source inlet of the second-effect heating chamber, and a supplementary steam valve is installed on the supplementary steam pipe.

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