阅读说明：本技术 3-甲基吡啶废液的处理方法 (Treatment method of 3-methylpyridine waste liquid ) 是由 陈建伟 邵峰 梁倩 张群辉 于 2021-06-24 设计创作，主要内容包括：本发明涉及3-甲基吡啶废液的处理方法,依次经过以下步骤处理：进入蒸发器蒸发分离,蒸发器的操作条件为：压力10-101kPa,温度70-170℃,蒸发器蒸出的蒸汽进入第一精馏塔精馏,第一精馏塔的操作条件为压力10-101kPa,塔顶温度10-50℃,塔釜温度50-150℃,第一精馏塔的塔釜物料进入第二精馏塔精馏,第二精馏塔的操作条件为压力20-101kPa,塔顶温度40-85℃,塔釜温度90-150℃。本发明的处理方法能够从制药工业的含有3-甲基吡啶的废液中分离提纯得到高纯度的3-甲基吡啶产品,处理过程中不会产生腐蚀性高沸物对于后续设备造成腐蚀和堵塞,具有处理效果好,产品纯度高的优点。(The invention relates to a treatment method of 3-methylpyridine waste liquid, which comprises the following steps in sequence: entering an evaporator for evaporation and separation, wherein the operating conditions of the evaporator are as follows: the pressure is 10-101kPa, the temperature is 70-170 ℃, the steam evaporated by the evaporator enters a first rectifying tower for rectification, the operating conditions of the first rectifying tower are 10-101kPa, the top temperature is 10-50 ℃, the bottom temperature is 50-150 ℃, the bottom material of the first rectifying tower enters a second rectifying tower for rectification, the operating conditions of the second rectifying tower are 20-101kPa, the top temperature is 40-85 ℃, and the bottom temperature is 90-150 ℃. The treatment method can separate and purify the 3-methylpyridine product with high purity from the waste liquid containing the 3-methylpyridine in the pharmaceutical industry, does not generate corrosive high-boiling residues to corrode and block subsequent equipment in the treatment process, and has the advantages of good treatment effect and high product purity.)

1. A treatment method of 3-methylpyridine waste liquid is characterized by sequentially carrying out the following steps:

entering an evaporator for evaporation and separation, wherein the operating conditions of the evaporator are as follows: the pressure is 10-101kPa, the temperature is 70-170 ℃,

the steam evaporated by the evaporator enters a first rectifying tower for rectification, the operating conditions of the first rectifying tower are that the pressure is 10-101kPa, the temperature at the top of the tower is 10-50 ℃, the temperature at the bottom of the tower is 50-150 ℃,

the tower bottom material of the first rectifying tower enters a second rectifying tower for rectification, and the operating conditions of the second rectifying tower are that the pressure is 20-101kPa, the tower top temperature is 40-85 ℃, and the tower bottom temperature is 90-150 ℃.

2. The method of treating 3-methylpyridine waste liquid according to claim 1, wherein the vapor distilled from the evaporator enters a demister for defoaming and then enters the first distillation column.

3. The method of treating 3-methylpyridine waste liquid according to claim 2, wherein the demister is provided with one or more of a baffle, a mesh and a filler.

4. The method for treating 3-methylpyridine waste liquid according to claim 1, wherein the evaporator is one or more of a jacketed evaporator, an external evaporator and a membrane evaporator.

5. The method according to claim 4, wherein the membrane evaporator is a wiped film evaporator.

6. The method according to claim 1, wherein the high boiling substance comprises one or both of a high viscosity organic substance and a corrosive salt.

7. The method of treating 3-methylpyridine waste liquid according to claim 1, wherein the operating conditions of the evaporator are as follows: normal pressure, 160 ℃.

8. The method for treating 3-methylpyridine waste liquid according to claim 1, wherein the operating conditions of the first rectification column are as follows: normal pressure, tower top temperature 38 deg.c and tower kettle temperature 121 deg.c.

9. The method for treating 3-methylpyridine waste liquid according to claim 1, wherein the second distillation column is operated under the following conditions: normal pressure, tower top temperature 82 deg.c and tower kettle temperature 145 deg.c.

Technical Field

The invention relates to a method for treating 3-methylpyridine waste liquid.

Background

3-methylpyridine waste liquid generated in the pharmaceutical industry contains 3-methylpyridine in a large amount and impurities such as high boiling substances, acetonitrile, methylene chloride and water, and 3-methylpyridine is an important intermediate, and it is necessary to recover 3-methylpyridine in the waste liquid.

Disclosure of Invention

The invention mainly aims to treat and recover a 3-methylpyridine product from a 3-methylpyridine waste liquid.

In order to achieve the aim, the invention provides a method for treating 3-methylpyridine waste liquid, which sequentially comprises the following steps:

entering an evaporator for evaporation and separation, wherein the operating conditions of the evaporator are as follows: the pressure is 10-101kPa, the temperature is 70-170 ℃,

the steam evaporated by the evaporator enters a first rectifying tower for rectification, the operating conditions of the first rectifying tower are that the pressure is 10-101kPa, the temperature at the top of the tower is 10-50 ℃, the temperature at the bottom of the tower is 50-150 ℃,

the tower bottom material of the first rectifying tower enters a second rectifying tower for rectification, and the operating conditions of the second rectifying tower are that the pressure is 20-101kPa, the tower top temperature is 40-85 ℃, and the tower bottom temperature is 90-150 ℃.

In some embodiments, the steam distilled by the evaporator enters the demister for defoaming and then enters the first rectifying tower.

In some embodiments, the demister is provided with one or more of baffles, screens, and packing.

In some embodiments, the evaporator is one or more of a jacketed evaporator, an external evaporator and a membrane evaporator.

In some embodiments, the membrane evaporator is a wiped film evaporator.

In some embodiments, the high boiling substance comprises one or both of a high viscosity organic substance and a corrosive salt.

The treatment method can separate and purify the 3-methylpyridine product with high purity from the waste liquid containing the 3-methylpyridine in the pharmaceutical industry, does not generate corrosive high-boiling residues to corrode and block subsequent equipment in the treatment process, and has the advantages of good treatment effect and high product purity.

Drawings

FIG. 1 is a schematic flow diagram of the purification of 3-methylpyridine.

Detailed Description

The invention relates to a method for treating 3-methylpyridine waste liquid, which comprises the following steps in sequence:

entering an evaporator for evaporation and separation, wherein the operating conditions of the evaporator are as follows: the pressure is 10-101kPa, the temperature is 70-170 ℃, the high-viscosity substances, the corrosive sodium sulfonate, the sodium chloride and other salts existing in the waste liquid can be removed in an evaporator to form evaporation residue,

and (3) steam evaporated by the evaporator enters a first rectifying tower for rectification, the operating conditions of the first rectifying tower are that the pressure is 10-101kPa, the temperature of the top of the tower is 10-50 ℃, the temperature of a tower kettle is 50-150 ℃, and the first rectifying tower can preliminarily remove dichloromethane in waste liquid and acetonitrile and water under the operating conditions.

The tower bottom material of the first rectifying tower enters a second rectifying tower for rectification, and the operating conditions of the second rectifying tower are that the pressure is 20-101kPa, the tower top temperature is 40-85 ℃, and the tower bottom temperature is 90-150 ℃. Under the operating condition, the second rectifying tower can further remove the mixed water in the waste liquid, thereby obtaining the 3-methylpyridine product.

The invention is further described with reference to the following figures and examples. The contents in the present example are weight percentages unless otherwise specified.

The 3-methylpyridine wastewater treated in this example contains 61.4% of 3-methylpyridine, 8.8% of acetonitrile, 0.8% of water, 26.3% of dichloromethane, and 2.7% of high boiling substances, wherein the high boiling substances include corrosive salts and high-viscosity organic substances, and the corrosive salts include salts such as sodium sulfonate and sodium chloride.

The 3-methylpyridine waste liquid is sent into an evaporator for evaporation, the flow rate of the 3-methylpyridine waste liquid is 2000kg/h, the operation temperature of the evaporator is normal pressure, 160 ℃, the top of the evaporator is provided with the evaporated waste liquid steam containing 61.0% of 3-methylpyridine, 9.8% of acetonitrile, 0.9% of water and 28.3% of dichloromethane, the flow rate is 1847kg/h, the evaporation residue of the evaporator contains 66.5% of 3-methylpyridine, 1.8% of acetonitrile, 0.13% of water, 2.0% of dichloromethane and 29.57% of high boiling substances, the flow rate is 153kg/h, and the evaporation residue can be discharged as dangerous waste for treatment. The evaporator can be selected from jacketed, external and membrane evaporators, preferably membrane, especially wiped-film evaporators. The evaporator is preferably made of titanium or zirconium.

The waste liquid steam is firstly removed by a demister so as to prevent high-boiling substances from being entrained into the waste liquid steam. The demister can be provided with a baffle, death or filler to increase the defoaming effect, and the demister can be a pipeline demister. The packing used is preferably structured packing M252, M152.

Waste liquid steam enters a first rectifying tower for preliminary rectifying separation after being defoamed by a demister, and the operating conditions of the first rectifying tower are as follows: the normal pressure, the top temperature of 38 ℃ and the bottom temperature of 121 ℃ are achieved, the top discharge contains 0.26 percent of acetonitrile, 2.74 percent of water and 97.0 percent of dichloromethane, the flow rate is 536kg/h, and the bottom discharge contains 86.7 percent of 3-methylpyridine, 13.1 percent of acetonitrile and 0.2 percent of water, and the flow rate is 1311 kg/h.

The tower bottom discharge of the first rectifying tower enters a second rectifying tower for refining 3-methylpyridine, the tower top discharge is 98.5% of acetonitrile and 1.49% of water, the flow rate is 177kg/h, the tower bottom discharge is 3-methylpyridine with the content of more than 99.8% and acetonitrile with the content of less than 0.2%, and the flow rate is 1134 kg/h. The tower bottom discharge of the second rectifying tower can be directly used as a product of 3-methylpyridine.

In the above-mentioned rectification process of the first rectification tower and the second rectification tower, the top discharge of the first rectification tower and the second rectification tower can be used as the reflux of the demister and used for defoaming by being in reverse contact with the waste liquid steam, fig. 1 shows the situation that the top discharge of the first rectification tower partially flows back to the demister, in some embodiments, the top discharge of the second rectification tower can also be used as the reflux of the demister, or part of the top discharge of the first rectification tower and the second rectification tower can be used as the reflux of the demister at the same time.

The steam generated by the evaporator is condensed in the condenser after passing through a demister line equipped with a baffle, a wire mesh, or a packing. Part of the condensate is taken as a pipeline demister to flow back, part of the condensate is taken as a product, acetonitrile and picoline can be separated and recovered through a known process, and the recovery equipment is made of conventional 304 stainless steel. The in-line defoaming device is preferably structured packing M252 and M152, and the material is preferably 316L.

The embodiments of the present invention are merely illustrative, and not restrictive, of the scope of the claims, and other substantially equivalent alternatives may occur to those skilled in the art and are within the scope of the present invention.