Evaporation system for removing formaldehyde in glyphosate by inverse carnot cycle low temperature

Abstract

This invention relates to a reverse Carnot cycle low-temperature evaporation system for removing formaldehyde from glyphosate, comprising a single-reactor batch falling film evaporation system, a distillation system for removing glyphosate from steam, a reverse Carnot cycle-hot water flash evaporation system, and a closed vacuum system. It employs a reverse Carnot cycle heat source and a refrigeration unit. Hot water flash evaporation generates a negative pressure steam at 40-60°C, which serves as the heat source for the falling film heat exchanger. Simultaneously, chilled water at 10-30°C is provided as the cold source for the condenser. Low-temperature evaporation is used, with the evaporation temperature between 35-50°C. This prevents the glyphosate ammonium salt from decomposing and easily entering the distillate water. High-boiling-point steam containing glyphosate is condensed in the first-stage condenser. This condensate returns to the distillation column, while the distillate water and formaldehyde enter the second-stage condenser. The high-boiling-point glyphosate remains in the glyphosate ammonium salt solution. The resulting effluent has a glyphosate content of less than 0.3%. After passing through this system, the formaldehyde content of the glyphosate solution meets national standards, and the material is also concentrated.

Description

Technical Field

[0001] This invention belongs to the technical field of evaporation-distillation-concentration systems, and relates to an evaporation system for removing formaldehyde from glyphosate at low temperature using a reverse Carnot cycle. Background Technology

[0002] In the production process of glyphosate ammonium salt, the primary products usually obtained, such as glyphosate ammonium salt and sodium salt, do not meet the national standard GB / T 12686-2017 for glyphosate technical grade. The national standard requires that the glyphosate content be greater than 30% and the formaldehyde content be less than 0.6 g / kg.

[0003] This is particularly problematic during the production of glyphosate ammonium salt, as formaldehyde can react with ammonia to form hexamethylenetetramine, which is difficult to remove. Conventional removal processes use evaporation, which evaporates formaldehyde along with the glyphosate ammonium salt. The problem lies in the excessively high evaporation temperature; for example, using a conventional double-effect evaporator at 50-90℃, the glyphosate ammonium salt decomposes, resulting in glyphosate content in the distillate exceeding 1%, requiring additional equipment for glyphosate recovery. A conventional process route is as follows... Figure 1 As shown.

[0004] This invention employs a reverse Carnot cycle heat source-refrigeration unit, using hot water flash evaporation to obtain a 40-60℃ negative pressure steam source as the heat source for the falling film heat exchanger, while simultaneously providing 10-30℃ chilled water as the cold source for the condenser. A single-effect falling film batch processing operation is used to ensure that the concentration of glyphosate ammonium salt and formaldehyde levels meet the standards. This invention uses low-temperature evaporation, with an evaporation temperature between 35-50℃, preventing the glyphosate ammonium salt from decomposing and easily entering the distillate water. Simultaneously, this invention incorporates a small distillation column, using a pump circulation system. The distillate water and formaldehyde enter the second-stage condenser, while the higher-boiling-point glyphosate remains in the glyphosate ammonium salt solution. The resulting effluent has a glyphosate content of less than 0.3%, thus reducing the equipment investment required for subsequent membrane concentration and glyphosate recovery. Summary of the Invention

[0005] In view of this, in order to solve the problem that the evaporation temperature required for formaldehyde to be evaporated is too high in the above-mentioned process of producing glyphosate ammonium salt by evaporation, the glyphosate ammonium salt will decompose and the glyphosate content in the distilled water will be as high as 1% or more, and the equipment to be added for recovery of glyphosate is required, resulting in high equipment investment costs, the present invention provides an evaporation system for removing formaldehyde from glyphosate at low temperature by reverse Carnot cycle.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] An evaporation system for removing formaldehyde from glyphosate at low temperature using a reverse Carnot cycle includes a single-reactor batch falling film evaporation system, a distillation system for removing glyphosate from steam, a reverse Carnot cycle-hot water flash evaporation system, and a closed vacuum system.

[0008] The single-reactor batch falling film evaporation system includes an evaporation storage tank, a heater, a second-stage condenser, a falling film circulating magnetic pump, and an evaporation water vortex magnetic pump. The heater is installed on the top of the evaporation storage tank, and the upper part of the evaporation storage tank has a water inlet and a feed inlet. The second-stage condenser pipe is connected to the steam outlet at the bottom of the heater. The liquid outlet pipe at the bottom of the evaporation storage tank is connected to the liquid inlet at the top of the heater, and the falling film circulating magnetic pump is installed on the connecting pipe. The evaporation water vortex magnetic pump pipe is connected to the liquid outlet of the second-stage condenser.

[0009] The system for removing glyphosate from steam by distillation includes a distillation column installed on top of an evaporation storage tank, a first-stage condenser connected to the steam outlet at the top of the distillation column, and a distillation column vortex magnetic circulation pump connected between the feed inlet and the discharge outlet of the distillation column. The steam outlet at the top of the first-stage condenser is connected to the second-stage condenser. The distillation column is filled with Pall ring packing.

[0010] The reverse Carnot cycle-hot water flash steam generation system includes a reverse Carnot cycle heat source refrigerant unit and a hot water flash steam generator. The hot water flash steam generator is circulated and connected to the reverse Carnot cycle heat source refrigerant unit, and a hot water circulation pump is installed on the connecting pipeline. A hot water flash spray head is installed at the inlet end of the hot water flash steam generator, and the lower outlet end of the heater is connected to the hot water flash steam generator pipeline. The second-stage condenser is circulated and connected to the reverse Carnot cycle heat source refrigerant unit, and a chilled water circulation pump is installed on the connecting pipeline.

[0011] The closed vacuum system includes a water ring vacuum pump connected to the second-stage condenser, a vacuum water tank connected to the water ring vacuum pump, and a plate heat exchanger for cooling the water ring vacuum pump.

[0012] Furthermore, an inlet flow meter and an automatic inlet valve for the evaporation storage tank are installed on the pipeline where the water inlet is located, and a feed flow meter and an automatic feed valve for the evaporation storage tank are installed on the pipeline where the feed inlet is located. A non-condensable gas exhaust valve for the heater is installed on the pipeline connecting the second-stage condenser and the heater. The evaporation storage tank is equipped with a storage tank pressure sensor for easy observation of the pressure inside the storage tank and a storage tank magnetic float level gauge for easy observation of the liquid level inside the storage tank. A discharge valve for easy removal of the finished product and a liquid temperature sensor for easy monitoring of the liquid temperature are installed on the pipeline connecting the heater and the evaporation storage tank.

[0013] Furthermore, the vortex magnetic pump for distilled water is connected to a three-way valve for distilled water discharge with a distilled water flow meter, and the connecting pipeline is equipped with a one-way valve for condensate discharge and a condensate sampling port. The condensate containing formaldehyde is discharged according to the formaldehyde content, and the condensate sampling port facilitates sampling and testing of the discharged condensate containing formaldehyde.

[0014] Furthermore, the distillation column is equipped with a heater temperature sensor for easy monitoring of the feed liquid temperature and a heater pressure sensor for easy monitoring of the pressure inside the distillation column. The bottom water inlet pipe of the first-stage condenser is equipped with a cooling water inlet temperature sensor with an automatic regulating valve for the cooling water inlet, and the water outlet pipe is equipped with a cooling water outlet temperature sensor.

[0015] Furthermore, a hot water outlet temperature sensor is installed on the pipeline between the bottom outlet of the hot water flash steam generator and the reverse Carnot cycle heat source refrigerant unit to facilitate monitoring the outlet water temperature of the hot water flash steam generator, and a hot water return temperature sensor is installed on the pipeline between the reverse Carnot cycle heat source refrigerant unit and the upper inlet of the hot water flash steam generator to facilitate monitoring the inlet water temperature of the hot water flash steam generator.

[0016] Furthermore, the hot water flash steam generator is equipped with an automatic valve for controlling the amount of steam and a magnetic level gauge for easy observation of the liquid level in the hot water flash steam generator; a chilled water return temperature sensor is installed on the pipeline connecting the second-stage condenser and the chilled water circulation pump to facilitate monitoring of the chilled water temperature, and a chilled water inlet temperature sensor is installed on the pipeline connecting the reverse Carnot cycle heat source refrigerant unit and the second-stage condenser.

[0017] Furthermore, a one-way valve for the inlet of the water ring vacuum pump is installed on the connecting pipeline between the second-stage condenser and the water ring vacuum pump. The vacuum water tank is equipped with a magnetic float level gauge for easy monitoring of its liquid level and a water replenishment valve for easy water replenishment. An automatic drain valve for the vacuum water tank is installed on the connecting pipeline between the vacuum water tank and the vortex magnetic pump for distilled water. The second-stage condenser is equipped with a chilled water magnetic float level gauge for easy monitoring of its liquid level, a second-stage condenser pressure sensor for easy monitoring of its internal pressure, and an atmospheric connection valve for easy adjustment of the internal air pressure.

[0018] Furthermore, the evaporation temperature and absolute pressure of the feed liquid in the system are 35-50℃ and 6-12Kpa, respectively. The glyphosate product after evaporation meets national standards, with a glyphosate content >30% and a formaldehyde content <0.6g / kg. Simultaneously, the glyphosate content in the distilled water is less than 0.3%.

[0019] The beneficial effects of this invention are as follows:

[0020] 1. The evaporation system for removing formaldehyde from glyphosate at low temperature using a reverse Carnot cycle disclosed in this invention employs a reverse Carnot cycle heat source and a refrigeration unit. A negative pressure steam of 40-60°C is obtained through hot water flash evaporation as the heat source for a falling film heat exchanger. At the same time, chilled water of 10-30°C is provided as the cold source for the condenser, thereby achieving low-temperature evaporation. The evaporation temperature is between 35-50°C. At this temperature, glyphosate ammonium salt does not decompose and is not easily introduced into the evaporated water.

[0021] 2. The reverse Carnot cycle low-temperature evaporation system for removing formaldehyde from glyphosate disclosed in this invention adopts a single-effect falling film single-reactor batch processing operation mode to ensure that the concentration of glyphosate ammonium salt and the formaldehyde index meet the standards, with glyphosate content >30% and formaldehyde content <0.6g / kg.

[0022] 3. The reverse Carnot cycle low-temperature evaporation system for removing formaldehyde from glyphosate disclosed in this invention is equipped with a small distillation column. High-boiling-point vapors containing glyphosate are condensed in the first-stage condenser. This condensate returns to the distillation column, while formaldehyde-water vapor enters the second-stage condenser. Therefore, the high-boiling-point glyphosate remains in the glyphosate ammonium salt solution. The effluent obtained from the second-stage condenser has a glyphosate content of less than 0.3%.

[0023] 4. The reverse Carnot cycle low-temperature evaporation system for removing formaldehyde from glyphosate disclosed in this invention not only ensures that the formaldehyde content of the initial glyphosate solution meets national standards after passing through this system, but also concentrates the material. Using a reverse Carnot cycle unit, the power consumption for evaporating one ton of water is 150-180 kWh.

[0024] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0025] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0026] Figure 1 This is a flow chart of a conventional double-effect evaporation-membrane concentration and recovery process;

[0027] Figure 2 This is a schematic diagram of the evaporation system for low-temperature removal of formaldehyde from glyphosate using a reverse Carnot cycle according to the present invention.

[0028] Figure 3 For the present invention Figure 2A schematic diagram of the installation structure of the evaporation storage tank, heater, and distillation column;

[0029] Figure 4 For the present invention Figure 2 Schematic diagram of the installation structure of the first-stage condenser and the second-stage condenser;

[0030] Figure 5 For the present invention Figure 2 Schematic diagram of the installation structure of a closed-loop vacuum system.

[0031] Figure reference numerals: 1. Falling film circulating magnetic pump; 2. Discharge valve; 3. Evaporation storage tank; 4. Feed temperature sensor; 5. Inlet water flow meter; 6. Heater non-condensable gas exhaust valve; 7. Feed flow meter; 8. Heater; 9. Distillation column; 10. Heater temperature sensor; 11. Heater pressure sensor; 12. Storage tank pressure sensor; 13. Storage tank magnetic level gauge; 14. Distillation column vortex magnetic circulation pump; 15. First-stage condenser; 16. Cold water tower inlet water temperature sensor; 17. Cold water tower outlet water temperature sensor; 18. Steam generator magnetic level gauge; 19. Hot water flash steam generator; 20. Hot water outlet water temperature sensor; 21. Hot water return water temperature sensor; 22. Reverse Carnot cycle heat source-refrigerant system; 23. Chilled water return water temperature sensor; 24. Chilled water inlet water... 25. Water temperature sensor; 26. Condensate drain check valve; 27. Condensate sampling port; 28. Evaporated water vortex magnetic pump; 29. ​​Evaporated water flow meter; 30. Evaporated water drain three-way valve; 31. Vacuum water tank magnetic level gauge; 32. Vacuum water tank; 33. Water ring vacuum pump; 34. Water ring vacuum pump inlet check valve; 35. Chilled water magnetic level gauge; 36. Atmospheric connection valve; 37. Second-stage condenser pressure sensor; 38. Second-stage condenser; 39. Plate heat exchanger; 40. Vacuum water tank water supply valve; 41. Vacuum water tank automatic drain valve; 42. Steam generator automatic valve; 43. Cooling tower inlet automatic regulating valve; 44. Evaporation storage tank inlet automatic valve; 45. Evaporation storage tank feed automatic valve; 46. Hot water flash spray head; 47. Chilled water circulation pump; 48. Hot water circulation pump. Detailed Implementation

[0032] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0033] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable that some well-known structures and their descriptions may be omitted in the drawings.

[0034] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0035] like Figures 2-5 The evaporation system shown is a reverse Carnot cycle low-temperature removal system for formaldehyde from glyphosate, comprising a single-reactor batch falling film evaporation system, a distillation system for removing glyphosate from steam, a reverse Carnot cycle-hot water flash evaporation system, and a closed vacuum system.

[0036] The single-reactor batch falling film evaporation system includes a large-capacity evaporation storage tank 3, a heater 8, a second-stage condenser 37, a falling film circulation magnetic pump 1, and an evaporation water vortex magnetic pump 27. The heater 8 is installed on top of the evaporation storage tank 3, which has a water inlet and a feed inlet at its upper part. The second-stage condenser 37 is connected to the steam outlet at the bottom of the heater 8 via piping. The outlet at the bottom of the evaporation storage tank 3 is connected to the inlet at the top of the heater 8, and the falling film circulation magnetic pump 1 is installed on the connecting pipe. The evaporation water vortex magnetic pump 27 is connected to the outlet of the second-stage condenser 37 via piping. The heater 8 features a vertical falling film circulation system where the feed liquid flows through the tubes and the heat source steam flows through the shell, fully utilizing the tube wall for high evaporation capacity. The second-stage condenser 37 features steam flowing through the shell and cooling water flowing through the tubes.

[0037] An inlet flow meter 5 and an automatic inlet valve 43 are installed on the pipeline where the inlet of the evaporation storage tank 3 is located. A feed flow meter 7 and an automatic feed valve 44 are installed on the pipeline where the feed inlet is located. A heater non-condensable gas exhaust valve 6 is installed on the pipeline connecting the second-stage condenser 37 and the heater 8. The evaporation storage tank 3 is equipped with a storage tank pressure sensor 12 for easy observation of the pressure inside the evaporation storage tank 3 and a storage tank magnetic float level gauge 13 for easy observation of the liquid level inside the evaporation storage tank 3. A discharge valve 2 for easy removal of finished product and a liquid temperature sensor 4 for easy monitoring of the liquid temperature are installed on the pipeline connecting the heater 8 and the evaporation storage tank 3.

[0038] The vortex magnetic pump 27 for evaporating water is connected to a three-way valve 29 for evaporating water discharge with an evaporating water flow meter 28, and a one-way valve 25 for condensate water discharge and a condensate water sampling port 26 are installed on the connecting pipeline. The condensate water containing formaldehyde is discharged according to the formaldehyde content, and the condensate water sampling port 26 facilitates the sampling and testing of the discharged condensate water containing formaldehyde.

[0039] The glyphosate-containing raw material enters the evaporation storage tank 3 through the automatic feed valve 44. Under the action of the falling film circulating magnetic pump 1, it enters the tube side of the heater 8, flowing down the inner wall of the tube from top to bottom, evaporating and concentrating as it flows. The material taken out from the discharge valve 2 is sampled and analyzed until the formaldehyde content in the tank is qualified. After the liquid is qualified, all the liquid in the evaporation storage tank 3 is discharged into the finished product tank through the discharge valve 2. The evaporated water-formaldehyde vapor is condensed into liquid in the second-stage condenser 37 and discharged through the distillate water vortex magnetic pump 27. The distillate water is discharged through the three-way valve 29, which can be divided into high-formaldehyde distillate water and low-formaldehyde distillate water according to the time sequence. The condensate water evaporated initially has a higher formaldehyde content.

[0040] The system for removing glyphosate from steam by distillation includes a distillation column 9 installed at the top of the evaporation storage tank 3, a first-stage condenser 15 connected to the steam outlet at the top of the distillation column 9, and a distillation column vortex magnetic circulation pump 14 connected between the feed inlet and outlet of the distillation column 9. The steam outlet at the top of the first-stage condenser 15 is connected to a second-stage condenser 37. The distillation column 9 is filled with 3-5 meter high Pall ring packing. A heater temperature sensor 10 for monitoring the feed temperature and a heater pressure sensor 11 for monitoring the internal pressure of the distillation column 9 are installed on the distillation column 9. A cooling tower inlet water temperature sensor 16 with an automatic cooling tower inlet regulating valve 42 is installed on the bottom water inlet pipe of the first-stage condenser 15, and a cooling tower outlet water temperature sensor 17 is installed on the outlet pipe.

[0041] The first-stage condenser 15 is a four-tube first-stage condenser 15, characterized in that it removes excess heat from the system to avoid overheating, while simultaneously condensing high-boiling-point glyphosate vapor.

[0042] The distillation column 9 is equipped with a distillation column vortex magnetic circulation pump 14, which keeps the Pall ring packing in the distillation column in a moist state. When the glyphosate-water-formaldehyde vapor passes through, the heavy component high-boiling-point glyphosate in the gas phase is transferred to the liquid phase, thereby achieving separation and achieving the purpose of leaving glyphosate in the finished product and reducing the glyphosate content in the distillate water.

[0043] In distillation column 9, the vapor containing glyphosate-water-formaldehyde enters the first-stage condenser 15. Under the action of cooling water, it loses heat, and the high-boiling-point glyphosate condenses into liquid in the first-stage condenser 15 and returns to distillation column 9. The flow rate of the cooling water can be adjusted by the automatic regulating valve 42 at the inlet of the cooling water tower, and the inlet and outlet water temperatures can be monitored by the inlet water temperature sensor 16 and the outlet water temperature sensor 17. A baffle is installed at the bottom of the distillation column. Part of the condensed glyphosate-containing condensate returns to the evaporation storage tank 3, and part returns to the upper part of distillation column 9 through the distillation column vortex magnetic circulation pump 14, spraying it into the distillation column, thereby ensuring that all Pall rings in the distillation column are kept wet.

[0044] The reverse Carnot cycle-hot water flash steam generation system includes a reverse Carnot cycle heat source refrigerant unit and a hot water flash steam generator 19. A hot water circulation pump 47 is installed between the bottom outlet of the hot water flash steam generator 19 and the reverse Carnot cycle heat source refrigerant unit, and a hot water outlet temperature sensor 20 is installed on this pipeline to facilitate monitoring the outlet water temperature of the hot water flash steam generator 19. A hot water return temperature sensor 21 is installed on the pipeline between the reverse Carnot cycle heat source refrigerant unit and the upper inlet of the hot water flash steam generator 19 to facilitate monitoring the inlet water temperature of the hot water flash steam generator 19. A hot water flash spray head 45 is installed at the inlet end of the hot water flash steam generator 19 to facilitate uniform flash steaming. The lower outlet end of the heater 8 is connected to the pipeline of the hot water flash steam generator 19.

[0045] The hot water flash steam generator 19 is equipped with an automatic valve 41 for controlling the amount of steam and a magnetic level gauge 18 for easy observation of the liquid level in the hot water flash steam generator 19.

[0046] The hot water flash steam generator 19 continuously provides stable steam to the heater 8, thereby enabling the falling film evaporator to evaporate stably. Formaldehyde in the feed liquid is converted into steam and leaves the feed liquid, thus removing formaldehyde.

[0047] The bottom outlet of the second-stage condenser 37 is connected to a chilled water circulation pump 46, and a chilled water return temperature sensor 23 is installed on this pipeline for easy monitoring of the chilled water temperature. The chilled water circulation pump 46 is connected to a reverse Carnot cycle heat source refrigerant unit to supply chilled water to the reverse Carnot cycle heat source refrigerant unit. The reverse Carnot cycle heat source refrigerant unit is connected to the second-stage condenser 37, and a chilled water inlet temperature sensor 24 is installed on the pipeline.

[0048] The reverse Carnot cycle heat source refrigerant unit is connected to the second-stage condenser 37 of the single-reactor batch falling film evaporation system via a chilled water circulation pump 46. The chilled water gains heat after passing through the second-stage condenser 37, while the evaporated water-formaldehyde vapor generated by the single-reactor batch falling film evaporation system is condensed into liquid. The reverse Carnot cycle heat source refrigerant unit is also connected to a hot water flash steam generator 19 via a hot water circulation pump 47. The hot water passes through a hot water flash spray head 45 to generate negative pressure steam with a temperature of 40-60℃ and an absolute pressure of 8-20 kPa. This negative pressure steam enters the heater 8 of the single-reactor batch falling film evaporation system, where it transfers heat to the feed liquid and condenses back into water, returning to the hot water flash steam generator 19.

[0049] Hot water circulating pump 47, reverse Carnot cycle heat source refrigerant unit, and chilled water circulating pump 46 form a reverse Carnot cycle heat source-refrigerant system 22. The reverse Carnot cycle heat source-refrigerant system 22 is characterized by its ability to efficiently utilize thermal energy, achieve heat transfer between relatively low-temperature heat sources, and rationally recover and utilize thermal energy, reducing energy waste and saving energy consumption for the system, achieving an efficiency of 150-180 kWh to evaporate one ton of water.

[0050] The closed-loop vacuum system includes a water ring vacuum pump 32 connected to the second-stage condenser 37, a vacuum water tank 31 connected to the water ring vacuum pump 32, and a plate heat exchanger 38. A one-way valve 33 is installed on the connecting pipe between the second-stage condenser 37 and the water ring vacuum pump 32. The vacuum water tank 31 is equipped with a magnetic float level gauge 30 for easy monitoring of its liquid level and a water replenishment valve 39 for easy water replenishment. An automatic drain valve 40 is installed on the connecting pipe between the vacuum water tank 31 and the evaporation water vortex magnetic pump 27. The second-stage condenser 37 is equipped with a chilled water magnetic float level gauge 34 for easy monitoring of its liquid level, a second-stage condenser pressure sensor 36 for easy monitoring of its internal pressure, and an atmospheric connection valve 35 for easy adjustment of the internal air pressure. The water ring vacuum pump 32 is characterized by creating a vacuum in the system, resulting in low-temperature evaporation, preventing the decomposition of glyphosate ammonium salt. The evaporation temperature and absolute pressure of the feed liquid in the system are 35-50℃ and 6-12Kpa, respectively.

[0051] In the second-stage condenser 37, some of the water vapor—formaldehyde vapor—is extracted by the water ring vacuum pump 32 and enters the vacuum water tank 31, causing the water level to rise. Excess water is discharged through the vacuum water tank's automatic drain valve 40. The working water of the water ring vacuum pump 32 is cooled by the plate heat exchanger 38, thereby ensuring the system's vacuum level.

[0052] The glyphosate product after evaporation treatment meets national standards, with a glyphosate content >30% and a formaldehyde content <0.6g / kg. Simultaneously, the glyphosate content in the distillate water is less than 0.3%.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An evaporation system for low-temperature removal of formaldehyde from glyphosate using a reverse Carnot cycle, characterized in that, This includes a single-reactor batch falling film evaporation system, a distillation system for removing glyphosate from steam, a reverse Carnot cycle-hot water flash evaporation system, and a closed vacuum system; The single-reactor batch falling film evaporation system includes an evaporation storage tank (3), a heater (8), a second-stage condenser (37), a falling film circulating magnetic pump (1), and an evaporation water vortex magnetic pump (27). The heater (8) is installed on the top of the evaporation storage tank (3). The evaporation storage tank (3) has a water inlet and a feed inlet at the top. The second-stage condenser (37) is connected to the bottom steam outlet of the heater (8). The bottom outlet of the evaporation storage tank (3) is connected to the top inlet of the heater (8), and the falling film circulating magnetic pump (1) is installed on the connecting pipe. The evaporation water vortex magnetic pump (27) is connected to the outlet of the second-stage condenser (37). The system for removing glyphosate from steam by distillation includes a distillation column (9) installed on top of the evaporation storage tank (3), a first-stage condenser (15) connected to the upper steam outlet of the distillation column (9), and a distillation column vortex magnetic circulation pump (14) connected between the feed inlet and the discharge outlet of the distillation column (9). The upper steam outlet of the first-stage condenser (15) is connected to the second-stage condenser (37). The distillation column (9) is filled with Pall ring packing. The reverse Carnot cycle-hot water flash generation system includes a reverse Carnot cycle heat source refrigerant unit and a hot water flash steam generator (19). The hot water flash steam generator (19) is circulated and connected to the reverse Carnot cycle heat source refrigerant unit, and a hot water circulation pump (47) is installed on the connecting pipeline. A hot water flash spray head (45) is installed at the water inlet end of the hot water flash steam generator (19). The water outlet end of the heater (8) is connected to the hot water flash steam generator (19) through a pipeline. The second-stage condenser (37) is circulated and connected to the reverse Carnot cycle heat source refrigerant unit, and a chilled water circulation pump (46) is installed on the connecting pipeline. The closed vacuum system includes a water ring vacuum pump (32) connected to a second-stage condenser (37), a vacuum water tank (31) connected to the water ring vacuum pump (32), and a plate heat exchanger (38) for cooling the water ring vacuum pump (32).

2. The evaporation system as described in claim 1, characterized in that, The inlet of the evaporation storage tank (3) is equipped with an inlet flow meter (5) and an automatic inlet valve (43) for the evaporation storage tank. The inlet of the feed is equipped with a feed flow meter (7) and an automatic feed valve (44) for the evaporation storage tank. The pipe connecting the second-stage condenser (37) and the heater (8) is equipped with a heater non-condensable gas exhaust valve (6). The evaporation storage tank (3) is equipped with a storage tank pressure sensor (12) for easy observation of the pressure inside the evaporation storage tank (3) and a storage tank magnetic float level gauge (13) for easy observation of the liquid level inside the evaporation storage tank (3). The pipe connecting the heater (8) and the evaporation storage tank (3) is equipped with a discharge valve (2) for easy removal of finished products and a liquid temperature sensor (4) for easy monitoring of the liquid temperature.

3. The evaporation system as described in claim 2, characterized in that, The vortex magnetic pump (27) for distilled water is connected to a three-way valve (29) for distilled water discharge with a distilled water flow meter (28), and a one-way valve (25) for condensate discharge and a condensate sampling port (26) are provided on the connecting pipeline. The condensate containing formaldehyde is discharged according to the formaldehyde content, and the condensate sampling port (26) facilitates the sampling and testing of the discharged condensate containing formaldehyde.

4. The evaporation system as described in claim 1, characterized in that, The distillation column (9) is equipped with a heater temperature sensor (10) for easy monitoring of the feed liquid temperature and a heater pressure sensor (11) for easy monitoring of the pressure inside the distillation column (9). The bottom water inlet pipe of the first-stage condenser (15) is equipped with a cold water tower inlet water temperature sensor (16) with an automatic regulating valve (42) for cold water tower inlet water, and the outlet water pipe is equipped with a cold water tower outlet water temperature sensor (17).

5. The evaporation system as described in claim 1, characterized in that, A hot water outlet temperature sensor (20) is installed on the pipeline between the bottom outlet of the hot water flash steam generator (19) and the reverse Carnot cycle heat source refrigerant unit to facilitate monitoring the outlet water temperature of the hot water flash steam generator (19). A hot water return temperature sensor (21) is installed on the pipeline between the reverse Carnot cycle heat source refrigerant unit and the upper inlet of the hot water flash steam generator (19) to facilitate monitoring the inlet water temperature of the hot water flash steam generator (19).

6. The evaporation system as described in claim 5, characterized in that, The hot water flash steam generator (19) is equipped with an automatic valve (41) for controlling the amount of steam and a magnetic float level gauge (18) for easy observation of the liquid level in the hot water flash steam generator (19); a chilled water return temperature sensor (23) for easy monitoring of chilled water temperature is installed on the pipeline connecting the second-stage condenser (37) and the chilled water circulation pump (46); a chilled water inlet temperature sensor (24) is installed on the pipeline connecting the reverse Carnot cycle heat source refrigerant unit and the second-stage condenser (37).

7. The evaporation system as described in claim 1, characterized in that, A water ring vacuum pump inlet check valve (33) is installed on the connecting pipe between the second-stage condenser (37) and the water ring vacuum pump (32). A vacuum water tank magnetic float level gauge (30) for easy monitoring of its liquid level and a vacuum water tank water replenishment valve (39) for easy water replenishment are installed on the vacuum water tank (31). An automatic vacuum water tank drain valve (40) is installed on the connecting pipe between the vacuum water tank (31) and the evaporation water vortex magnetic pump (27). A chilled water magnetic float level gauge (34) for easy monitoring of its liquid level, a second-stage condenser pressure sensor (36) for easy monitoring of its internal pressure, and an atmospheric connection valve (35) for easy adjustment of the internal air pressure are installed on the second-stage condenser (37).

8. The evaporation system as described in claim 1, characterized in that, The evaporation system has an evaporation temperature and absolute pressure of 35-50℃ and 6-12Kpa, respectively. The glyphosate product after evaporation meets national standards, with a glyphosate content >30% and a formaldehyde content <0.6g / kg; at the same time, the glyphosate content in the distilled water is less than 0.3%.

Images