阅读说明：本技术 一种农化废溶剂回收提纯方法及装置 (Method and device for recovering and purifying agricultural chemical waste solvent ) 是由 范文林 黄啟虓 纪王洋 鲁加峰 于 2021-06-09 设计创作，主要内容包括：本发明公开了一种农化废溶剂回收提纯方法及装置,包括：废液箱、多个原料箱、变压精馏塔、分离塔、中转收集塔、水收集箱、成品箱以及耙式干燥机；本发明涉及溶剂再生和溶剂纯化技术领域,降低了农化行业、和新型农药、新型技术多肽生产中废溶剂对环境的污染程度,节约了生产成本。本发明提供的提纯方法还具有收率高、能耗低、品质好、能回用、生产过程简便、运行稳定、适用于工业化生产等优点。(The invention discloses a method and a device for recovering and purifying an agricultural chemical waste solvent, which comprises the following steps: the system comprises a waste liquid tank, a plurality of raw material tanks, a pressure swing rectifying tower, a separation tower, a transfer collecting tower, a water collecting tank, a finished product tank and a rake dryer; the invention relates to the technical field of solvent regeneration and solvent purification, reduces the pollution degree of waste solvents to the environment in the agricultural chemical industry, novel pesticides and novel technical polypeptide production, and saves the production cost. The purification method provided by the invention also has the advantages of high yield, low energy consumption, good quality, capability of recycling, simple and convenient production process, stable operation, suitability for industrial production and the like.)

1. An agricultural chemical waste solvent recovery and purification device comprises: the device comprises a waste liquid tank, a plurality of raw material tanks, a variable-pressure rectifying tower, a separating tower, a transfer collecting tower, a water collecting tank, a finished product tank and a rake dryer, and is characterized in that the waste liquid tank is connected to the variable-pressure rectifying tower, the raw material tanks and the transfer collecting tower are connected to the variable-pressure rectifying tower through a transfer drainage structure, the separating tower is connected to the variable-pressure rectifying tower, the water collecting tank is mounted at the bottom end of the separating tower, the finished product tanks and the rake dryer are connected to the variable-pressure rectifying tower, a raw material adding structure is mounted in the variable-pressure rectifying tower, and the raw material adding structure is connected to the transfer drainage structure;

the raw material adding structure comprises: the stirring device comprises a plurality of feeding shaft tubes, a plurality of feeding stirring chain wheels, a plurality of stirring sheets, a plurality of stirring chains, a plurality of stirring driving machines, a plurality of stirring transfer bearings and a plurality of shunt tubes;

the material loading axostylus axostyle respectively through the bearing cartridge in the vary voltage rectifying column, it is a plurality of material loading driving machine is even install in on the high pressure rectifying column, it is a plurality of material loading stirring sprocket installs respectively in a plurality of material loading axostylus axostyle and a plurality of stirring driving machine drive end, it is a plurality of stirring chain suit respectively in a plurality of on the stirring sprocket, it is a plurality of stirring transfer bearing piece installs respectively in a plurality of on the material loading axostylus axostyle, it is a plurality of the stirring piece install respectively in a plurality of on the material loading axostylus axostyle.

2. The recycling and purifying apparatus for agricultural and chemical waste solvent as claimed in claim 1, wherein the transfer drainage structure comprises: the device comprises a support bracket, a plurality of transfer boxes, a plurality of transfer air exhaust drivers, a plurality of transfer driving bevel gears, a plurality of transfer transmission bevel gears, a plurality of transfer lifting threaded pipes, a plurality of transfer lifting threaded rods, a plurality of transfer adsorption plates and a plurality of sealing valves;

the plurality of transfer boxes are arranged on the supporting bracket, the plurality of transfer air exhaust drivers are respectively arranged on the plurality of transfer boxes, the plurality of transfer driving bevel gears are respectively arranged on the driving ends of the plurality of transfer air exhaust drivers, the plurality of transfer lifting threaded pipes are respectively inserted on the plurality of transfer boxes through bearings, the plurality of transfer transmission bevel gears are respectively arranged on the plurality of transfer lifting threaded pipes, the plurality of transfer transmission bevel gears are respectively meshed with the plurality of transfer driving bevel gears, the plurality of transfer lifting threaded rods are respectively and movably inserted into the plurality of transfer lifting threaded pipes, the plurality of transfer adsorption plates are respectively arranged on the plurality of transfer lifting threaded rods, the plurality of sealing valves are respectively arranged on two sides of the plurality of transfer boxes, and the other ends of the sealing valves are respectively connected to the shunt pipes and the transfer collecting tower.

3. The recycling and purifying device for the agricultural and chemical waste solvent as claimed in claim 2, wherein a plurality of temperature sensors and pressure sensors are arranged in the pressure swing distillation tower.

4. The recycling and purifying device of agricultural and chemical waste solvent as claimed in claim 3, wherein an electric heating coil is disposed in the separation tower.

5. A method for recovering and purifying agricultural chemical waste solvent is characterized by comprising the following operation steps of S1, mixing solution; step S2, circulating reflux separation; step S3, collection; step S4, drying;

the step S1: introducing an agricultural chemical waste solvent containing sulfonate, sodium chloride and 3-methylpyridine into a pressure swing distillation tower at a certain flow rate, and rectifying and separating waste liquid at a certain temperature and under a certain pressure;

the step S2: the tower top component separated by rectification is an organic component azeotroped with water, the component enters a pervaporation membrane device in a steam form by controlling certain flow and pressure, dehydration is carried out, the organic solvent after moisture removal returns to the pressure swing rectification tower, and the moisture of an organic phase in the pressure swing rectification tower is removed in a circulating manner;

the step S3: extracting the finished product of the 3-methylpyridine at a certain flow rate from the side line position of the pressure swing rectifying tower; obtaining industrial grade 3-methylpyridine with the purity of more than or equal to 98.5 percent (wt);

the step S4: and (3) putting the materials in the rectifying tower kettle into a rake dryer at a certain flow rate, and drying to obtain the sulfonate and the sodium chloride.

6. The method and the device for recovering and purifying the agricultural and chemical waste solvent, according to claim 5, characterized in that in the step 1, the feed flow of the waste liquid of the pressure swing distillation tower is 0.1-2m3/h, the pressure of the pressure swing distillation is 0-0.5Mpa, the temperature of the bottom of the distillation kettle is 80-135 ℃, the temperature of the liquid in the kettle is 77-131 ℃, the temperature of the top of the kettle is 75-130 ℃, and the reflux ratio is controlled to be 30: 1-0.5: 1.

7. the method for recycling and purifying the agricultural chemical waste solvent according to claim 6, wherein in the step 2, pressure swing distillation and a membrane device are coupled for use, the gas phase at the top of the distillation tower is directly fed into the membrane device for dehydration, the flow rate of the gas phase component fed into the pervaporation membrane is 0.1-3 m3/h, and an organic solvent azeotropic with water is added at the top of the pressure swing distillation tower, wherein the azeotropic agent comprises dichloromethane, n-hexane, n-heptane, cyclohexane, toluene, benzene, ethanol, isopropanol, methyl tert-butyl ether, acetonitrile and the like.

8. The method for recycling and purifying the agricultural and chemical waste solvent as claimed in claim 7, wherein in the step 3, the finished product of 3-methylpyridine is extracted from the side line of the pressure swing distillation tower at a flow rate of 0.05-1.3m 3/h.

9. The method for recycling and purifying the agricultural chemical waste solvent as claimed in claim 8, wherein in the step 4, the material in the bottom of the pressure swing distillation tower is dried in a rake dryer, and the flow rate of the material in the rake dryer is 0.03-0.7m 3/h.

10. The method for recycling and purifying the agricultural and chemical waste solvent according to claim 9, further comprising the steps of controlling the pressure of the pressure swing distillation system to be constant, maintaining the whole purification process to be a continuous process, extracting materials from the pressure swing distillation tower in a certain proportion, and dehydrating by using a pervaporation membrane under the condition of reduced pressure.

Technical Field

The invention relates to the technical field of solvent regeneration and solvent purification, in particular to a method and a device for recovering and purifying an agricultural chemical waste solvent.

Background

With the development of organic synthesis technology and design skill of pesticide active molecules and the demand of agricultural production for new pesticides, various pyridine-containing pesticides appeared after 60 years. The dao chemical company developed triclopyr and the Shi Yuan company developed fluazifop and the like. Imidacloprid and the like have been developed by Bayer company in Germany and by Special pesticide company in Japan. Nowadays, pyridine-based pesticides have developed into a wide variety including bactericides, insecticides and acaricides, herbicides and plant growth regulators. A large amount of 3-methylpyridine waste liquid containing impurities such as organic matters, water, salts and the like is generated in pesticide production, and the 3-methylpyridine waste liquid is high in purification difficulty, is mostly discarded and is not used any more, so that great waste is caused, and the environment is also greatly polluted after the 3-methylpyridine waste liquid is discharged. The invention aims to overcome the defects in the prior art, and the method comprises the steps of performing pressure swing rectification, azeotropic rectification and pervaporation membrane integrated coupling technology, recycling an azeotropic solvent, extracting a product from the side of rectification, and drying the residual liquid in a tower kettle in a rake dryer to remove water and other organic and inorganic impurities in a 3-methylpyridine waste solvent and efficiently recover 3-methylpyridine to achieve the purpose of recycling.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method and a device for recovering and purifying an agricultural chemical waste solvent, which solve part of the problems of the prior art.

In order to achieve the purpose, the invention is realized by the following technical scheme: an agricultural chemical waste solvent recovery and purification device comprises: the system comprises a waste liquid tank, a plurality of raw material tanks, a variable-pressure rectifying tower, a separating tower, a transfer collecting tower, a water collecting tank, a finished product tank and a rake dryer, wherein the waste liquid tank is connected to the variable-pressure rectifying tower;

the raw material adding structure comprises: the stirring device comprises a plurality of feeding shaft tubes, a plurality of feeding stirring chain wheels, a plurality of stirring sheets, a plurality of stirring chains, a plurality of stirring driving machines, a plurality of stirring transfer bearings and a plurality of shunt tubes;

the material loading axostylus axostyle respectively through the bearing cartridge in the vary voltage rectifying column, it is a plurality of material loading driving machine is even install in on the high pressure rectifying column, it is a plurality of material loading stirring sprocket installs respectively in a plurality of material loading axostylus axostyle and a plurality of stirring driving machine drive end, it is a plurality of stirring chain suit respectively in a plurality of on the stirring sprocket, it is a plurality of stirring transfer bearing piece installs respectively in a plurality of on the material loading axostylus axostyle, it is a plurality of the stirring piece install respectively in a plurality of on the material loading axostylus axostyle.

Preferably, the transit drainage structure comprises: the device comprises a support bracket, a plurality of transfer boxes, a plurality of transfer air exhaust drivers, a plurality of transfer driving bevel gears, a plurality of transfer transmission bevel gears, a plurality of transfer lifting threaded pipes, a plurality of transfer lifting threaded rods, a plurality of transfer adsorption plates and a plurality of sealing valves;

the plurality of transfer boxes are arranged on the supporting bracket, the plurality of transfer air exhaust drivers are respectively arranged on the plurality of transfer boxes, the plurality of transfer driving bevel gears are respectively arranged on the driving ends of the plurality of transfer air exhaust drivers, the plurality of transfer lifting threaded pipes are respectively inserted on the plurality of transfer boxes through bearings, the plurality of transfer transmission bevel gears are respectively arranged on the plurality of transfer lifting threaded pipes, the plurality of transfer transmission bevel gears are respectively meshed with the plurality of transfer driving bevel gears, the plurality of transfer lifting threaded rods are respectively and movably inserted into the plurality of transfer lifting threaded pipes, the plurality of transfer adsorption plates are respectively arranged on the plurality of transfer lifting threaded rods, the plurality of sealing valves are respectively arranged on two sides of the plurality of transfer boxes, and the other ends of the sealing valves are respectively connected to the shunt pipes and the transfer collecting tower.

Preferably, a plurality of temperature sensors and pressure sensors are arranged in the pressure swing rectifying tower.

Preferably, an electric heating coil pipe is arranged in the separation tower.

A method for recovering and purifying agricultural chemical waste solvent comprises the following operation steps of S1, mixing solution; step S2, circulating reflux separation; step S3, collection; step S4, drying;

the step S1: introducing an agricultural chemical waste solvent containing sulfonate, sodium chloride and 3-methylpyridine into a pressure swing distillation tower at a certain flow rate, and rectifying and separating waste liquid at a certain temperature and under a certain pressure;

the step S2: the tower top component separated by rectification is an organic component azeotroped with water, the component enters a pervaporation membrane device in a steam form by controlling certain flow and pressure, dehydration is carried out, the organic solvent after moisture removal returns to the pressure swing rectification tower, and the moisture of an organic phase in the pressure swing rectification tower is removed in a circulating manner;

the step S3: extracting the finished product of the 3-methylpyridine at a certain flow rate from the side line position of the pressure swing rectifying tower; obtaining industrial grade 3-methylpyridine with the purity of more than or equal to 98.5 percent (wt);

the step S4: and (3) putting the materials in the rectifying tower kettle into a rake dryer at a certain flow rate, and drying to obtain the sulfonate and the sodium chloride.

In the step 1, the feed flow of the waste liquid of the pressure swing distillation tower is 0.1-2m3/h, the pressure of the pressure swing distillation is 0-0.5Mpa, the temperature of the bottom of the distillation kettle is 80-135 ℃, the temperature of the liquid in the kettle is 77-131 ℃, the temperature of the top of the kettle is 75-130 ℃, and the reflux ratio is controlled to be 30: 1-0.5: 1.

in the step 2, the pressure swing distillation and the membrane device are coupled for use, the gas phase at the top of the distillation tower is directly fed into the membrane device for dehydration, the flow rate of gas phase components fed into the pervaporation membrane is 0.1-3 m3/h, and an organic solvent azeotropic with water is added at the top of the pressure swing distillation tower, wherein the azeotropic agent comprises dichloromethane, normal hexane, normal heptane, cyclohexane, toluene, benzene, ethanol, isopropanol, methyl tert-butyl ether, acetonitrile and the like.

In the step 3, the finished product of the 3-methylpyridine is extracted from the side line position of the pressure swing rectification tower, and the extracted flow is 0.05-1.3m 3/h.

In the step 4, the materials in the tower bottom of the pressure swing distillation tower enter a rake dryer for drying, and the flow rate of the materials entering the rake dryer is 0.03-0.7m 3/h.

The method also comprises the steps of controlling the pressure of the pressure swing distillation system to be unchanged, maintaining the whole purification process to be a continuous process, extracting materials from the pressure swing distillation tower in a certain proportion, and dehydrating by using the pervaporation membrane under the condition of reduced pressure.

The invention provides a method and a device for recovering and purifying an agricultural chemical waste solvent. The method has the following beneficial effects: the method and the device for recovering and purifying the agricultural chemical waste solvent reduce the pollution degree of the waste solvent to the environment in the agricultural chemical industry, the production of novel pesticides and novel technical polypeptides, and save the production cost. The purification method provided by the invention also has the advantages of high yield, low energy consumption, good quality, capability of recycling, simple and convenient production process, stable operation, suitability for industrial production and the like.

Drawings

FIG. 1 is a schematic flow chart of a method and a device for recovering and purifying an agricultural chemical waste solvent according to the present invention.

FIG. 2 is a schematic sectional view of the agricultural chemical waste solvent recovery and purification method and apparatus according to the present invention.

FIG. 3 is a schematic top sectional view of the method and apparatus for recovering and purifying the waste agricultural solvent according to the present invention.

Fig. 4 is an enlarged view of the structure of the portion "a" in fig. 2.

Fig. 5 is an enlarged view of the structure of the portion "B" in fig. 2.

In the figure: 1. a waste liquid tank; 2. a raw material tank; 3. a pressure swing rectifying tower; 4. a separation column; 5. a transfer collection tower; 6. a feeding shaft tube; 7. a feeding stirring chain wheel; 8. a stirring sheet; 9. a stirring chain; 10. a stirring driver; 11. stirring the transfer bearing; 12. a shunt tube; 13. a support bracket; 14. a transfer box; 15. a transfer air pumping driver; 16. transferring and driving the bevel gear; 17. transferring and transmitting the helical gear; 18. transferring the lifting threaded pipe; 19. transferring the lifting threaded rod; 20. a transfer adsorption plate; 21. and sealing the valve.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

All the electrical components in the present application are connected with the power supply adapted to the electrical components through a wire, and an appropriate controller and an appropriate encoder should be selected according to actual conditions to meet control requirements, and specific connection and control sequences should be obtained.

As shown in fig. 1 to 5, an apparatus for recovering and purifying agricultural chemical waste solvent comprises: the device comprises a waste liquid box 1, a plurality of raw material boxes 2, a variable-pressure rectifying tower 3, a separation tower 4, a transfer collection tower 5, a water collection box, a finished product box and a rake dryer, wherein the waste liquid box 1 is connected to the variable-pressure rectifying tower 3, the raw material boxes 2 and the transfer collection tower 5 are connected to the variable-pressure rectifying tower 3 through a transfer drainage structure, the separation tower 4 is connected to the variable-pressure rectifying tower 3, the water collection box is mounted at the bottom end of the separation tower 4, the finished product boxes and the rake dryer are connected to the variable-pressure rectifying tower 3, a raw material adding structure is mounted in the variable-pressure rectifying tower 3, and the raw material adding structure is connected to the drainage structure; the raw material adding structure comprises: a plurality of feeding shaft pipes 6, a plurality of feeding stirring chain wheels 7, a plurality of stirring sheets 8, a plurality of stirring chains 9, a plurality of stirring driving machines 10, a plurality of stirring transfer bearings 11 and a plurality of shunt pipes 12; the feeding shaft pipes 6 are respectively inserted into the pressure swing rectifying tower 3 through bearings, the plurality of feeding driving machines are uniformly arranged on the high-pressure rectifying tower, the plurality of feeding stirring chain wheels 7 are respectively arranged at the driving ends of the plurality of feeding shaft pipes 6 and the plurality of stirring driving machines 10, the plurality of stirring chains 9 are respectively sleeved on the plurality of stirring chain wheels, the plurality of stirring transfer bearings 11 are respectively arranged on the plurality of feeding shaft pipes 6, and the plurality of stirring sheets 8 are respectively arranged on the plurality of feeding shaft pipes 6; the transfer drainage structure includes: a support bracket 13, a plurality of transfer boxes 14, a plurality of transfer air-extracting drivers 15, a plurality of transfer drive bevel gears 16, a plurality of transfer drive bevel gears 17, a plurality of transfer lifting threaded pipes 18, a plurality of transfer lifting threaded rods 19, a plurality of transfer adsorption plates 20 and a plurality of sealing valves 21; the plurality of the transit boxes 14 are mounted on the support bracket 13, the plurality of the transit air-extracting drivers 15 are respectively mounted on the plurality of the transit boxes 14, the plurality of the transit driving bevel gears 16 are respectively mounted on the driving ends of the plurality of the transit air-extracting drivers 15, the plurality of the transit lifting threaded pipes 18 are respectively inserted on the plurality of the transit boxes 14 through bearings, the plurality of the transit transmission bevel gears 17 are respectively mounted on the plurality of the transit lifting threaded pipes 18, the plurality of the transit transmission bevel gears 17 are respectively engaged with the plurality of the transit driving bevel gears 16, the plurality of the transit lifting threaded pipes 19 are respectively inserted in the plurality of the transit lifting threaded pipes 18 in a movable manner, the plurality of the transit adsorption plates 20 are respectively mounted on the plurality of the transit lifting threaded pipes 19, the plurality of the sealing valves 21 are respectively mounted on both sides of the plurality of the transit boxes 14, the other ends of the plurality of sealing valves 21 are respectively connected to the plurality of shunt tubes 12 and the transfer collecting tower 5; a plurality of temperature sensors and pressure sensors are arranged in the pressure swing rectifying tower 3; an electric heating coil pipe is arranged in the separation tower 4.

A method for recovering and purifying agricultural chemical waste solvent comprises the following operation steps of S1, mixing solution; step S2, circulating reflux separation; step S3, collection; step S4, drying; the step S1: introducing an agricultural chemical waste solvent containing sulfonate, sodium chloride and 3-methylpyridine into a pressure swing distillation tower 3 at a certain flow rate, and rectifying and separating the waste liquid at a certain temperature and under a certain pressure; the step S2: the tower top component separated by rectification is an organic component azeotroped with water, the component enters a pervaporation membrane device in a steam form by controlling certain flow and pressure, dehydration is carried out, the organic solvent after moisture removal returns to the pressure swing rectification tower 3, and the moisture of an organic phase in the pressure swing rectification tower 3 is removed in a circulating manner; the step S3: 3-methylpyridine finished products are extracted from the side line position of 3 parts of the pressure swing rectifying tower at a certain flow rate; obtaining industrial grade 3-methylpyridine with the purity of more than or equal to 98.5 percent (wt); the step S4: putting the materials in the rectifying tower kettle into a rake dryer at a certain flow rate, and drying to obtain sulfonate and sodium chloride; in the step 1, the feed flow of the waste liquid of the pressure swing distillation tower 3 is 0.1-2m3/h, the pressure of the pressure swing distillation is 0-0.5Mpa, the temperature of the bottom of the distillation kettle is 80-135 ℃, the temperature of the liquid in the kettle is 77-131 ℃, the temperature of the top of the kettle is 75-130 ℃, and the reflux ratio is controlled to be 30: 1-0.5: 1; in the step 2, the pressure swing distillation and the membrane device are coupled for use, the gas phase at the top of the distillation tower is directly fed into the membrane device for dehydration, the flow rate of gas phase components fed into the pervaporation membrane is 0.1-3 m3/h, and an organic solvent azeotropic with water is added at the top of the pressure swing distillation tower 3, wherein the azeotropic agent comprises dichloromethane, normal hexane, normal heptane, cyclohexane, toluene, benzene, ethanol, isopropanol, methyl tert-butyl ether, acetonitrile and the like; in the step 3, the finished product of the 3-methylpyridine is extracted from the side line position of the pressure swing rectifying tower 3, and the extracted flow is 0.05-1.3m 3/h; in the step 4, the materials at the tower bottom of the pressure swing rectifying tower 3 enter a rake dryer for drying, and the flow rate of the materials entering the rake dryer is 0.03-0.7m 3/h; the method also comprises the steps of controlling the pressure of the pressure swing distillation system to be unchanged, maintaining the whole purification process to be a continuous process, extracting materials from the pressure swing distillation tower 3 in a certain proportion, and dehydrating by using a pervaporation membrane under the condition of reduced pressure.

From the above, it follows: the agricultural chemical waste solvent in the raw material box 2 is guided into the pressure swing rectifying tower 3, the agricultural chemical waste solvent is pressurized and vaporized through the pressure swing rectifying tower 3, the agricultural chemical waste solvent is vaporized and guided into liquid on a plurality of flow distribution plates through siphons on the plurality of flow distribution plates in the pressure swing rectifying tower 3, a plurality of transfer air exhaust drivers 15 are operated to respectively drive transfer driving helical gears 16 on the transfer driving helical gears to rotate, the transfer driving helical gears 16 respectively drive transfer driving helical gears 17 engaged with the transfer driving helical gears to rotate, the transfer lifting threaded pipes 18 are respectively driven to rotate through the transfer driving helical gears 17, the transfer lifting threaded rods 19 in the transfer lifting threaded pipes 18 are respectively driven to lift through the transfer lifting threaded pipes 18, so that the transfer lifting threaded rods 19 respectively lift along the transfer lifting threaded pipes 18, and a plurality of sealing valves 21 connected to the raw material boxes 2 and the transfer boxes 14 are simultaneously opened, the transfer adsorption plates 20 on the transfer adsorption plates are respectively driven by the transfer lifting threaded rods 19, the liquid in the raw material boxes 2 is respectively drained into the transfer boxes 14 by the transfer adsorption plates 20, the seal valves 21 on the raw material boxes 2 and the transfer boxes 14 are closed, the seal valves 21 on the transfer boxes 14 and the variable-pressure rectifying tower 3 are opened, the transfer air-extracting drivers 15 are reversely operated, the transfer driving bevel gears 16 on the transfer air-extracting drivers 15 are reversely driven to rotate by the transfer air-extracting drivers 15, so that the transfer adsorption plates 20 are descended along the transfer boxes 14, the liquid pumped into the transfer boxes 14 is pumped to the shunt tubes 12 in the variable-pressure rectifying tower 3, the feeding stirring chain wheels 7 on the driving ends of the stirring drivers 10 are respectively driven to rotate by the stirring drivers 10, and the stirring chains 9 on the stirring chain wheels 7 are respectively driven to rotate by the feeding stirring chain wheels 7, a plurality of stirring chains 9 respectively drive a plurality of feeding stirring chain wheels 7 on the stirring chains to rotate, a plurality of feeding stirring chain wheels 7 respectively drive a plurality of feeding shaft pipes 6 on the stirring chains to rotate, a plurality of shunt pipes 12 are used for draining dichloromethane, normal hexane, normal heptane, cyclohexane, toluene, benzene, ethanol, isopropanol, methyl tert-butyl ether, acetonitrile and other raw materials onto the feeding shaft pipes 6, the raw materials are respectively drained into a pressure swing distillation tower 3 through holes on the feeding shaft pipes 6, the steam and mixed liquid are stirred and mixed through the feeding shaft pipes 6 which rotate, thereby accelerating distillation reaction, the distilled agricultural chemical waste solvent is drained into a separation tower 4, the moisture in the steam is filtered out through the separation tower 4, the filtered liquid is drained into a transfer collection tower 5, the steam is drained into the pressure swing distillation tower 3 again through a transfer drainage structure connected to the transfer collection tower 5, thereby achieving the effect of circular distillation, wherein the feed flow of the waste liquid of the pressure swing distillation tower 3 is 0.1-2m3/h, the pressure of the pressure swing distillation is 0-0.5Mpa, the temperature of the bottom of the distillation kettle is 80-135 ℃, the temperature of the liquid in the kettle is 77-131 ℃, the temperature of the top of the kettle is 75-130 ℃, and the reflux ratio is controlled to be 30: 1-0.5: 1; coupling pressure swing distillation and a membrane device for use, directly feeding gas phase at the top of a distillation tower into the membrane device for dehydration, wherein the flow rate of gas phase components fed into an pervaporation membrane is 0.1-3 m3/h, and adding an organic solvent azeotropic with water at the top of the pressure swing distillation tower 3, wherein the azeotropic agent comprises dichloromethane, n-hexane, n-heptane, cyclohexane, toluene, benzene, ethanol, isopropanol, methyl tert-butyl ether, acetonitrile and the like; 3-methylpyridine finished products are extracted from the side line position of the pressure swing rectifying tower 3, and the extracted flow is 0.05-1.3m 3/h; feeding the materials in the 3-tower kettle of the pressure swing rectifying tower into a rake dryer for drying, wherein the flow rate of the materials fed into the rake dryer is 0.03-0.7m 3/h; the method also comprises the steps of controlling the pressure of the pressure swing distillation system to be unchanged, maintaining the whole purification process to be a continuous process, extracting materials from the pressure swing distillation tower 3 in a certain proportion, and dehydrating by using a pervaporation membrane under the condition of reduced pressure.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation. The use of the phrase "comprising one of the elements does not exclude the presence of other like elements in the process, method, article, or apparatus that comprises the element.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.