阅读说明：本技术 一种2-甲基吡啶废液的回收提纯方法 (Recovery and purification method of 2-methylpyridine waste liquid ) 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2-甲基吡啶废液的回收提纯方法,包括以下步骤：a.取含磺酸盐及氯化钠、2-甲基吡啶的农化废料,以一定流量通入变压精馏塔中,在一定温度、压力下精馏废料；b.上述精馏的塔顶组分是与水共沸的有机组成,该组成以蒸汽形式,控制一定的流量、压力进入渗透汽化膜,进行脱水,脱除水分后的有机溶剂以一定流量通入变压精馏塔,循环脱除变压精馏塔中水分；c.2-甲基吡啶成品从变压精馏塔侧线位置,以一定流量采出。本发明通过变压精馏,渗透汽化膜耦合精馏脱水,共沸溶剂循环使用,产品侧线采出,塔釜物料耙式干燥机构干燥的方法,得到工业级2-甲基吡啶,有利于从含磺酸盐及氯化钠的农化废溶剂中提纯工业级2-甲基吡啶。(The invention discloses a method for recovering and purifying 2-methylpyridine waste liquid, which comprises the following steps: a. taking the agricultural chemical waste containing sulfonate, sodium chloride and 2-methylpyridine, introducing the agricultural chemical waste into a pressure swing distillation tower at a certain flow rate, and rectifying the waste at a certain temperature and pressure; b. the tower top component of the rectification is an organic component azeotropic with water, the component enters a pervaporation membrane in a steam form by controlling certain flow and pressure, dehydration is carried out, the organic solvent after moisture removal is introduced into a pressure swing rectification tower in a certain flow, and the moisture in the pressure swing rectification tower is removed in a circulating manner; and c, extracting the finished 2-methylpyridine at a certain flow rate from the side line position of the pressure swing rectifying tower. The method obtains the industrial-grade 2-methylpyridine by pressure swing rectification, pervaporation membrane coupling rectification dehydration, azeotropic solvent recycling, product side line extraction and tower kettle material rake drying mechanism drying, and is favorable for purifying the industrial-grade 2-methylpyridine from the agricultural chemical waste solvent containing sulfonate and sodium chloride.)

1. The method for recovering and purifying the 2-methylpyridine waste liquid is characterized by comprising the following steps:

a. the agricultural chemical waste containing sulfonate, sodium chloride and 2-methylpyridine is introduced into a pressure swing rectifying tower at a certain flow rate, and the waste is rectified at a certain temperature and pressure.

b. The tower top component of the rectification is an organic component azeotropic with water, the component enters a pervaporation membrane in a steam form by controlling certain flow and pressure, dehydration is carried out, the organic solvent after moisture removal is introduced into a pressure swing rectification tower in a certain flow, and the moisture in the pressure swing rectification tower is removed in a circulating manner.

c, extracting the finished 2-methylpyridine at a certain flow rate from the side line position of the pressure swing distillation tower; obtaining the industrial grade 2-methylpyridine with the purity more than or equal to 99.9 percent (wt).

d. And (3) putting the materials in the rectifying tower kettle into a rake type drying mechanism according to a certain flow rate, and drying to obtain the sulfonate and the sodium chloride.

2. The method for recovering and purifying the waste solvent of 2-methylpyridine according to claim 1, wherein the flow rate of the waste material entering the pressure swing distillation tower in the step a is 0.1-2m³/h；

In the step a, the pressure of pressure swing rectification is 0-0.5MPa, the temperature of the bottom of a rectification kettle is 85-133 ℃, the temperature of liquid in the kettle is 80-128 ℃, the temperature of the top of the kettle is 79-128 ℃, and the reflux ratio is controlled to be 30: 1-1: 1.

3. the method for recovering and purifying the waste 2-methylpyridine solvent according to claim 1, wherein in the step b, pressure swing distillation is coupled with a membrane device, and the gas phase at the top of the distillation tower is directly fed into the membrane device for dehydration;

in the step b, the flow rate of the azeotropic component entering the pervaporation membrane is 0.1-2m³/h；

In the step b, the organic solvent dehydrated by the membrane device returns to the top of the pressure swing distillation tower for circulation reflux separation;

in the step b, an organic solvent azeotropic with water is added at the top of the pressure swing distillation tower, and the azeotropic agent comprises dichloromethane, n-hexane, n-heptane, cyclohexane, toluene, benzene, ethanol, isopropanol, methyl tert-butyl ether, acetonitrile and the like.

4. The method for recovering and purifying 2-methylpyridine waste solvent according to claim 1, wherein in the step c, the 2-methylpyridine finished product is extracted from the side line of the pressure swing distillation tower at a flow rate of 0.01-1m³/h。

5. The method for recovering and purifying the waste solvent of 2-methylpyridine according to claim 1, wherein in the step d, the material in the bottom of the pressure swing distillation tower is dried by a rake drying mechanism, and the flow rate of the material in the rake drying mechanism is 0.01-1m³/h。

6. The method for recycling and purifying 2-methylpyridine waste liquid according to claim 1, wherein the rake type drying mechanism in step d comprises a base (1), both sides of the upper end of the base (1) are provided with a support base (2), the upper end of the support base (2) is fixedly connected with a drying cylinder (3), one end of the drying cylinder (3) is provided with a discharge port, the other end of the drying cylinder is provided with a stirring motor (4), the output end of the stirring motor (4) is connected with a stirring shaft (5), one end of the stirring shaft (5) far away from the stirring motor (4) is rotatably connected with the inner side wall of the stirring cylinder (3), the stirring shaft (5) is equidistantly provided with a plurality of groups of mixing and stirring mechanisms (6), and the middle part of one end of each mixing and stirring mechanism (6) is rotatably connected with a mixing and drying mechanism (8).

7. The method for recycling and purifying 2-methylpyridine waste liquid according to claim 6, wherein the mixing and stirring structure (6) comprises a support rod (61), a spring (62) is installed in one end of the outer side of the support rod (61), the other end of the spring (62) is connected with a movable rod, a mounting seat (63) is fixedly installed at one end of the movable rod far away from the spring, a roller (64) is rotatably connected to the mounting seat (63), a plurality of limiting blocks (7) are correspondingly arranged on the inner side wall of the drying cylinder (3) and the mixing and stirring mechanism (6), the limiting blocks (7) are fan-shaped, and the limiting blocks (7) and the roller (64) are arranged in a staggered mode.

8. A method for recovering and purifying 2-methylpyridine waste liquid according to claim 7, wherein the mixing and drying mechanism (8) comprises a heating screen (81) and a mixing shaft (82), one end of the mixing shaft (82) is fixedly connected with the support rod (64), and the heating screen (81) is disposed on the mixing shaft (82).

9. The method for recovering and purifying the waste solvent of 2-methylpyridine according to claim 1, further comprising the steps of;

(1) controlling the pressure of the rectification system to be unchanged, and maintaining the whole purification process to be a continuous process;

(2) extracting the materials from the pressure swing rectifying tower according to a certain proportion;

(3) the pervaporation membrane dehydrates under reduced pressure.

Technical Field

The invention relates to the technical field of waste solvent purification, in particular to a method for recovering and purifying 2-methylpyridine waste liquid.

Background

With the development of organic synthesis technology and design skill of pesticide active molecules and the demand of agricultural production for new pesticides, a plurality of 2-methylpyridine-containing pesticides appeared after 60 years. The dao chemical company developed triclopyr, the Shi Yuan company developed fluazifop and the like, and the German Bayer company and the Japanese Special pesticide company developed imidacloprid and the like. Nowadays, 2-methylpyridine pesticides have developed a wide variety including fungicides, insecticides and acaricides, herbicides and plant growth regulators. A large amount of 2-methylpyridine waste solvent containing impurities such as organic matters, water, salts and the like is generated in the production of pesticides, and because the purification difficulty is high, most of the waste solvent is not used any more, the waste is great, and the environment is also polluted after the waste solvent is discharged; simultaneously in the prior art to the dry recovery technique of material of distillation column tower cauldron limited, utilize current drying process equipment can not fully contact the waste material, influence the dry use of material, the inside certain residue waste liquid of adhesion of drying device simultaneously influences the recovery weight of solution, is unfavorable for drying equipment cleanness.

Disclosure of Invention

The invention aims to solve the defects in the prior art and provides a method for recovering and purifying 2-methylpyridine waste liquid.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for recovering and purifying 2-methylpyridine waste liquid comprises the following steps:

a. the agricultural chemical waste containing sulfonate, sodium chloride and 2-methylpyridine is introduced into a pressure swing rectifying tower at a certain flow rate, and the waste is rectified at a certain temperature and pressure.

b. The tower top component of the rectification is an organic component azeotropic with water, the component enters a pervaporation membrane in a steam form by controlling certain flow and pressure, dehydration is carried out, the organic solvent after moisture removal is introduced into a pressure swing rectification tower in a certain flow, and the moisture in the pressure swing rectification tower is removed in a circulating manner.

c, extracting the finished 2-methylpyridine at a certain flow rate from the side line position of the pressure swing distillation tower; obtaining the industrial grade 2-methylpyridine with the purity more than or equal to 99.9 percent (wt).

d. And (3) putting the materials in the rectifying tower kettle into a rake type drying mechanism according to a certain flow rate, and drying to obtain the sulfonate and the sodium chloride.

Preferably, in the step a, the flow rate of the waste material entering the pressure swing distillation tower is 0.1-2m³/h；

In the step a, the pressure of pressure-variable rectification is 0-0.5MPa, the temperature of the bottom of a rectification kettle is 85-133 ℃, the temperature of liquid in the kettle is 80-128 ℃, the temperature of the top of the kettle is 79-128 ℃, and the reflux ratio is controlled to be 30: 1-1: 1.

preferably, in the step b, the pressure swing rectification and the membrane device are coupled and used, and the gas phase at the top of the rectification tower is directly fed into the membrane device for dehydration;

in the step b, the flow rate of the azeotropic component entering the pervaporation membrane is 0.1-2m³/h；

In the step b, the organic solvent dehydrated by the membrane device returns to the top of the pressure swing distillation tower for circulation reflux separation;

in the step b, an organic solvent azeotropic with water is added at the top of the pressure swing distillation tower, and the azeotropic agent comprises dichloromethane, n-hexane, n-heptane, cyclohexane, toluene, benzene, ethanol, isopropanol, methyl tert-butyl ether, acetonitrile and the like.

Preferably, in the step c, the finished 2-methylpyridine product is extracted from the side line position of the pressure swing distillation tower, and the extracted flow is 0.01-1m³/h。

Preferably, in the step d, the materials in the tower bottom of the pressure swing distillation tower enter a rake drying mechanism for drying, and the flow rate entering the rake drying mechanism is 0.01-1m³/h。

Preferably, harrow formula drying mechanism includes base 1 in step d, and 1 upper end both sides of base all are provided with supporting seat 2, and 2 upper ends fixedly connected with drying cylinder 3 of supporting seat, one end is provided with the discharge gate on the drying cylinder 3, and agitator motor 4 is installed to the other end, and agitator motor 4 output is connected with (mixing) shaft 5, and agitator motor 4's one end is kept away from to (mixing) shaft 5 is connected with the rotation of 3 inside walls of agitator cylinder, and the equidistance is provided with multiunit mixing and stirring mechanism 6 on (mixing) shaft 5, and 6 one end middle parts of mixing and stirring structure rotate and be connected with mix dry mechanism 8.

Preferably, mix stirring structure 6, install spring 62 in a tip including bracing piece 61, bracing piece 61 outside, the spring 62 other end is connected with the movable rod, and the one end fixed mounting that the spring was kept away from to the movable rod has mount pad 63, rotates on the mount pad 63 to be connected with gyro wheel 64, corresponds with mixing stirring mechanism 6 on 3 inside walls of drying cylinder to be provided with a plurality of stopper 7, and stopper 7 is fan-shaped, and a plurality of stopper 7 and a plurality of gyro wheel 64 crisscross setting.

Preferably, the mixing and drying mechanism 8 comprises a heating screen 81 and a mixing shaft 82, one end of the mixing shaft 82 is fixedly connected with the support rod 64, and the heating screen 81 is arranged on the mixing shaft 82.

Preferably, the method further comprises the step;

(1) controlling the pressure of the rectification system to be unchanged, and maintaining the whole purification process to be a continuous process;

(2) extracting the materials from the pressure swing rectifying tower according to a certain proportion;

(3) the pervaporation membrane dehydrates under reduced pressure.

Compared with the prior art, the invention has the beneficial effects that:

1. the industrial-grade 2-methylpyridine is obtained by a method of pressure swing rectification, pervaporation membrane coupling rectification dehydration, azeotropic solvent recycling, product side line extraction and tower kettle material rake drying mechanism drying, and is favorable for purifying the industrial-grade 2-methylpyridine from an agricultural chemical waste solvent containing sulfonate and sodium chloride;

2. the purification method of industrial grade 2-methylpyridine provided by the invention has the advantages that the waste solvent of the 2-methylpyridine with the purity of only 50-70% (wt) is purified to the industrial grade 2-methylpyridine with the purity of more than or equal to 99.9% (wt) through a series of procedures of pressure swing rectification, pervaporation membrane dehydration, azeotropic solvent recycling, product side line extraction and drying of a tower kettle material rake type drying mechanism with low energy consumption, so that the waste solvent of the 2-methylpyridine with the purity of more than or equal to 99.9% (wt) is recycled, the pollution degree of the waste solvent to the environment in the agricultural chemical industry, novel pesticide and novel technical polypeptide production is reduced, and the production cost is saved.

3. 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.

4. According to the invention, through the unique arrangement of the rake type drying mechanism, the waste materials can be fully stirred in the heating process, the contact area of the waste materials is increased, the rapid drying and use of the materials are facilitated, and the rollers can continuously knock the side wall of the drying cylinder by utilizing the matching of the movable rods, the rollers and the limiting blocks, so that the materials are vibrated and slide, the mixing of waste residues is facilitated, the full collection of the materials is facilitated, and the cleaning of a dryer is facilitated.

Drawings

FIG. 1 is a schematic flow diagram of a method for recovering and purifying 2-methylpyridine waste liquid according to the present invention;

FIG. 2 is a schematic structural diagram of a rake drying mechanism in the method for recovering and purifying 2-methylpyridine waste liquid according to the present invention;

FIG. 3 is an enlarged view of portion A of FIG. 2;

FIG. 4 is a schematic view of the internal structure of a rake drying mechanism in the method for recovering and purifying 2-methylpyridine waste liquid according to the present invention;

FIG. 5 is a schematic view of the connection of the mixing and drying mechanism of the rake drying mechanism in the method for recovering and purifying 2-methylpyridine waste liquid according to the present invention;

fig. 6 is a schematic connection diagram of a mixing and drying mechanism of a middle rake type drying mechanism in the method for recovering and purifying 2-methylpyridine waste liquid provided by the invention.

In the figure: the device comprises a base 1, a support 2, a drying cylinder 3, a stirring motor 4, a stirring shaft 5, a stirring shaft 6, a mixing and stirring mechanism, a support rod 61, a spring 62, a mounting seat 63, a roller 64, a limiting block 7, a mixing and drying mechanism 8, a heating screen plate 81 and a mixing shaft 82.

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.

Example 1

According to the figure 1, the method for recovering and purifying the waste solvent of the 2-methylpyridine is characterized by comprising the following steps:

taking waste solvent containing 55% 2-methylpyridine at a ratio of 0.5m³Pumping the mixture into a pressure swing distillation tower, and performing positive pressure distillation to obtain an isopropanol-water azeotropic component at the tower top, wherein the pressure swing distillation conditions are as follows: the pressure is 0.2MPa, the temperature of the bottom of the rectifying kettle is 102 ℃, the temperature of liquid in the kettle is 99 ℃, the temperature of the top of the kettle is 98 ℃, and the reflux ratio is 15: 1.

The isopropyl alcohol-water azeotropic component obtained by the above rectification was adjusted to 1.5m³Introducing vapor in a form of/h into a pervaporation membrane, and circularly introducing the dehydrated isopropanol into a pressure swing rectifying tower.

0.20m from the side line of the pressure swing rectifying tower³Extracting 2-methylpyridine; obtaining the industrial grade 2-methylpyridine with the purity more than or equal to 99.9 percent (wt).

The material in the bottom of the rectifying tower is 0.13m³And putting the mixture into a rake type drying mechanism for drying to obtain the sulfonate and the sodium chloride.

Example 2

Based on embodiment 1, the method for recovering and purifying the waste 2-methylpyridine solvent is characterized by comprising the following steps:

taking waste solvent containing 60% 2-methylpyridine at a ratio of 0.6m³Pumping the mixture into a pressure swing distillation tower, and performing positive pressure distillation to obtain an isopropanol-water azeotropic component at the tower top, wherein the pressure swing distillation conditions are as follows: the pressure is 0.5MPa, the temperature of the bottom of the rectifying kettle is 121 ℃, the temperature of liquid in the kettle is 118 ℃, the temperature of the top of the kettle is 117 ℃, and the reflux ratio is 20: 1.

The isopropyl alcohol-water azeotropic component obtained by the above rectification is added in an amount of 1m³Introducing vapor in a form of/h into a pervaporation membrane, and circularly introducing the dehydrated isopropanol into a pressure swing rectifying tower.

0.29m from the side line of the pressure swing rectifying tower³Extracting 2-methylpyridine; obtaining the industrial grade 2-methylpyridine with the purity more than or equal to 99.9 percent (wt).

The material in the bottom of the rectifying tower is 0.19m³Putting into a rake type drying mechanism for drying to obtainTo sulfonates and sodium chloride.

The technical indexes of the industrial grade 2-methylpyridine after purification in the examples 1-2 are shown in the table one:

watch 1

By adopting the scheme, the purity can be greatly improved;

further, referring to fig. 2-6, in the drying process, the material in the distillation tower kettle is placed into a rake type drying mechanism according to a certain flow rate, a stirring shaft 5 and a mixing and stirring mechanism 6 are driven to rotate by a stirring motor 4, a support rod 61 in the mixing and stirring mechanism 6 drives a mixing and drying mechanism 8 to rotate, the material is heated and dried by a heating screen plate 81 in the mixing and drying mechanism, and meanwhile, the material is fully stirred and mixed by matching the heating screen plate 81 and a mixing shaft 82, so that the drying of the material is facilitated, and the recovery of a solvent is facilitated; simultaneously, through the matching of the support rod 61, the spring 62, the movable rod mounting seat 63 and the roller 64, the roller 64 makes reciprocating motion on the limiting block 7, hits the wall of the drying cylinder, shakes off the residual material, is convenient for fully collecting the material, and is beneficial to cleaning of the dryer.

The industrial-grade 2-methylpyridine is obtained by a method of pressure swing rectification, pervaporation membrane coupling rectification dehydration, azeotropic solvent recycling, product side line extraction and tower kettle material rake drying mechanism drying, and is favorable for purifying the industrial-grade 2-methylpyridine from an agricultural chemical waste solvent containing sulfonate and sodium chloride;

the purification method of industrial grade 2-methylpyridine provided by the invention has the advantages that the waste solvent of the 2-methylpyridine with the purity of only 50-70% (wt) is purified to the industrial grade 2-methylpyridine with the purity of more than or equal to 99.9% (wt) through a series of procedures of pressure swing rectification, pervaporation membrane dehydration, azeotropic solvent recycling, product side line extraction and drying of a tower kettle material rake type drying mechanism with low energy consumption, so that the waste solvent of the 2-methylpyridine with the purity of more than or equal to 99.9% (wt) is recycled, the pollution degree of the waste solvent to the environment in the agricultural chemical industry, novel pesticide and novel technical polypeptide production is reduced, and the production cost is saved.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.