CN114105798A - Method and equipment for continuously preparing high-purity glycine by mother liquor circulation - Google Patents
Method and equipment for continuously preparing high-purity glycine by mother liquor circulation Download PDFInfo
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Abstract
The invention provides a method for continuously preparing high-purity glycine by mother liquor circulation, which comprises the following steps: in an ammoniation reaction system, ammonium chloroacetate reacts with liquid ammonia under the catalysis of urotropine to generate glycine crystals; then the reaction liquid is slowly cooled in multiple stages, and the crystallization is increased; dissolving ammonium chloride in the mother liquor, feeding a small part of the mother liquor into a recovery system to recover methanol, ammonium chloride and urotropine, feeding a large part of the mother liquor into a reaction crystallization system to precipitate ammonium chloride, and centrifuging the mother liquor to return to an ammoniation reaction system. The invention also provides equipment for continuously preparing the high-purity glycine by circulating the mother liquor. The glycine preparation method provided by the invention can realize continuous production of glycine, reduce production energy consumption, reduce equipment investment, improve production efficiency and reduce cost.
Description
Technical Field
The invention belongs to the technical field of chemical production and separation, and particularly relates to a method and equipment for continuously preparing high-purity glycine by circulating mother liquor.
Background
Glycine is an important raw material for producing products such as glyphosate, glycine ethyl ester hydrochloride and the like, and can also be used in the fields of food, feed and the like. The domestic main production method comprises the following steps: chloroacetic acid is used as a raw material and is subjected to ammonolysis reaction with liquid ammonia under the catalysis of urotropine to produce glycine and simultaneously co-produce ammonium chloride. The method is generally adopted in China for water phase reaction, and glycine is obtained by separating a large amount of methanol after the reaction is finished; the method not only needs to consume a large amount of energy to recover the methanol, but also causes the decomposition of the urotropine and generates a large amount of waste water containing organic matters in the process of recovering the ammonium chloride, thereby polluting the environment and increasing the production cost.
In recent years, a process for producing glycine using methanol as a solvent has been reported. In the ammonolysis reaction, glycine and ammonium chloride are simultaneously separated out in a mixed crystal mode, and the obtained mixed crystal is separated after the reaction is finished. In the prior art, a batch kettle type reaction is utilized, ammonia gas is introduced into a methanol solution of chloroacetic acid and urotropine to obtain mixed crystals and a mother solution, and centrifugal separation is carried out. However, the batch still requires a long time for cooling after the reaction is completed, and there are risks of back mixing, long residence time and runaway of heat release, which results in long reaction period and high production cost. In the process of mixed crystal separation, an alcohol-water mixed solvent is required to obtain glycine solid, and the mother liquor is required to be subjected to processes of methanol evaporation and most of water evaporation, temperature reduction and crystallization to obtain crude ammonium chloride solid, so that the energy consumption is high.
CN 111960958 (a method for preparing glycine by using an alcohol-water solvent solid chloroacetic acid) and CN 111196768 (a method for preparing glycine by using a homoionic effect) directly use an alcohol-water mixed solvent for reaction, thereby avoiding the generation of mixed crystals and simplifying the separation process; meanwhile, ammonium chloride in the mother liquor can be separated out by utilizing ammonium chloroacetate prepared from the raw materials. However, the purity of the prepared glycine is lower than 99%, and the content of chloride ions is higher.
Disclosure of Invention
In order to solve the defects of the prior art, the invention provides a method for continuously preparing high-purity glycine by mother liquor circulation, so that the glycine production efficiency is improved, and the production energy consumption is reduced.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a method for continuously preparing high-purity glycine by mother liquor circulation is characterized in that: the method comprises the following steps: step one, circulating mother liquor returned from an ammonium chloride reaction crystallization system is supplemented with water, methanol and a urotropine catalyst; in an alcohol-water mixed solvent, ammonium chloroacetate reacts with liquid ammonia at a certain temperature and within a certain pH range to generate glycine which is crystallized and separated out; the step is carried out in a chloroacetic acid ammoniation reaction system. Secondly, after the ammoniation reaction is finished, the reaction liquid is slowly cooled in multiple stages, and the crystallization is increased; centrifugally separating out a solid glycine crude product, and simultaneously dissolving the byproduct ammonium chloride in the mother liquor; the step is carried out in a multi-stage cooling crystallization system. Thirdly, the circulating mother liquor dissolved with the ammonium chloride in the second step enters a reaction crystallizer, then chloroacetic acid melt and liquid ammonia are added simultaneously, the temperature and the pH are controlled within a certain range, centrifugal separation is carried out to obtain crude ammonium chloride, and the mother liquor returns to an ammonification reaction system; this step is carried out in an ammonium chloride reaction crystallization system. The fourth step: secondly, taking a certain amount of the circulating mother liquor dissolved with the ammonium chloride, feeding the circulating mother liquor into a circulating mother liquor recovery system, respectively recovering methanol, ammonium chloride, urotropine and the like in the mother liquor by methods of rectification, crystallization, ammoniation and the like in sequence, and sending residual liquid to wastewater treatment; this step is carried out in a recycle mother liquor recovery system.
In a multi-stage cooling crystallization system, the reaction liquid is slowly cooled to 15-25 ℃ in multiple stages, and the crystallization is increased; meanwhile, the by-product ammonium chloride is dissolved in the mother liquor; a small part of mother liquor enters a recovery system, and methanol, ammonium chloride and urotropine are recovered by methods of rectification, crystallization, ammoniation and the like; most of mother liquor enters a reaction crystallization system, chloroacetic acid and liquid ammonia are added to slowly separate out ammonium chloride solids, and the mother liquor after centrifugal separation returns to an ammoniation reaction system.
Furthermore, in the multistage cooling crystallization system, the reaction liquid is cooled and crystallized by 2-4 stages, and the final temperature is reduced to 15-25 ℃.
Furthermore, in the reaction crystallization system, the reaction temperature is 10-20 ℃, and the reaction pH is controlled to be 6.3-7.5.
Further, the crystallizer in the reaction crystallization system is a kettle type reactor, and the mass ratio of chloroacetic acid melt to circulating mother liquor supplemented each time is as follows: 1: 5.5 to 10.5.
Further, the mother liquor is circulated to continuously prepare the high-purity glycine by the following preparation method:
(1) dissolving urotropine solid in a reaction kettle of a urotropine dosing tank by using water, pumping the dissolved urotropine solid into a raw material tank of the urotropine dosing tank by using a pump after the dissolution is finished, wherein the raw material tank is communicated with an ammoniation reactor through a pipeline, and a flow meter and a valve are arranged between the raw material tank and the ammoniation reactor, so that the amount of urotropine entering the ammoniation reactor can be controlled; feeding a circulating mother liquor returned from an ammonium chloride reaction crystallization system into an ammoniation reactor; simultaneously, replenishing a part of methanol from a methanol raw material tank; in an alcohol-water mixed solvent, ammonium chloroacetate reacts with liquid ammonia at a certain temperature and within a certain pH range to generate glycine which is crystallized and separated out;
(2) reducing the temperature of the ammoniation reaction liquid to a certain temperature through a multistage cooling crystallization reactor to obtain high-purity glycine; centrifugally separating solid glycine, and simultaneously dissolving by-product ammonium chloride in the mother liquor;
(3) most of mother liquor obtained by centrifugal separation enters a reaction crystallizer through a pipeline, chloroacetic acid melt and liquid ammonia are added from a chloroacetic acid raw material tank and a liquid ammonia tank through pumps, a flow meter and a valve are arranged between the raw material tank and the reaction crystallizer, and the amount of chloroacetic acid and the amount of liquid ammonia entering the reaction crystallizer can be controlled; in the reaction stage, the temperature and the pH are controlled within a certain range, and ammonium chloride solid is gradually separated out; after the feeding is finished, centrifugally separating the reaction system to obtain a crude product of ammonium chloride, and returning the mother liquor to the ammonification reaction system through a pipeline by a pump;
(4) and (2) a small part of the circulating mother liquor dissolved with ammonium chloride obtained by centrifugal separation in the step (1) enters a circulating mother liquor recovery system through a pipeline by a pump, methanol, ammonium chloride, urotropine and the like in the mother liquor are respectively recovered by methods of rectification, crystallization, ammoniation and the like, and residual liquid is sent to wastewater treatment.
Further, in the alcohol-water mixed solvent, the mass percent of the methanol is 70-90%.
Further, the temperature of the ammoniation reaction is 45-75 ℃, and the pH value of the reaction is controlled to be 6.3-7.5.
Further, in the ammoniation reaction, the mass ratio of the urotropine to the circulating mother liquor is 0.9-1.1: 14 to 16.
And further, 1-3% of the circulating mother liquor enters a circulating mother liquor recovery system, and methanol, ammonium chloride solid and urotropine solid are obtained through rectification, cooling crystallization and ammoniation processes in sequence.
Compared with the prior art, the method for continuously preparing the high-purity glycine by circulating the mother liquor has the following advantages:
(1) in the ammoniation reaction, an alcohol-water mixed solvent is adopted, so that the separation of glycine and ammonium chloride is realized while the reaction is carried out, and the step of mixed crystal separation in the alcohol process is avoided;
(2) after the ammoniation reaction is finished, a multi-stage cooling crystallization mode is adopted, so that the yield of the glycine can be improved, and the purity of the product can also be improved;
(3) in the reaction crystallization, ammonium chloride crystals are separated out by utilizing the reaction of the raw materials, namely chloroacetic acid and liquid ammonia, so that the solvent evaporation process in the original process is avoided, and the energy consumption is reduced;
(4) the method realizes the efficient circulating continuous production of the glycine by using the mother liquor circulating and continuous reaction modes, improves the reaction efficiency, stabilizes the product quality, is simple to operate, and is beneficial to the operation of technical personnel.
The invention also provides equipment for continuously preparing high-purity glycine by circulating the mother liquor, which comprises the following steps: a chloroacetic acid ammoniation reaction system, a multi-stage cooling system, an ammonium chloride reaction crystallization system and a circulating mother liquor recovery system which are sequentially communicated; the chloroacetic acid ammonification reaction system comprises a raw material tank and an ammonification reactor, the ammonium chloride reaction crystallization system comprises a reaction crystallizer, a centrifuge, and the circulating mother liquor recovery system comprises a distillation tower, a crystallizer and an ammonification reactor.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic diagram of a process flow for continuously and circularly preparing high-purity glycine from mother liquor.
Detailed Description
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
The first embodiment is as follows:
preparation of circulating mother liquor: preparing a mixed solvent by using 6.05kg of methanol and 1.51kg of water, introducing 1.27kg of chloroacetic acid and 0.23kg of liquid ammonia, and controlling the reaction temperature to be between 15 and 20 ℃ and the pH to be between 6.5 and 7.0 in the whole process.
Ammoniation reaction: dissolving urotropine 0.05kg in water 0.03kg in a reaction kettle of a urotropine dosing tank, stirring for 20min, feeding into a urotropine raw material tank, and feeding into an ammoniation reactor through a pump; simultaneously, 0.12kg of methanol is supplemented from a methanol storage tank, and the methanol and 7.56kg of circulating mother liquor dissolved with 1.27kg of chloroacetic acid and 0.23kg of liquid ammonia react together in an ammoniation reactor. In an alcohol-water mixed solvent for ammoniation reaction, the mass percent of methanol is 80.0 percent; controlling the reaction temperature between 63 ℃ and 67 ℃ and the pH between 6.5 and 7.0. As the reaction proceeded, the amount of white solid in the reactor gradually increased, and the reaction was completed after 1 hour. After the reaction is finished, slowly cooling the reaction liquid to 15-20 degrees in three stages, and increasing crystallization; pumping the reaction product in the reactor into a centrifugal machine by a pump, wherein the centrifugal speed is 10000rpm, the centrifugal time is 3min, and finally obtaining 2.04kg of glycine, the solid content is 50 percent, and the yield of the glycine is 98.9 percent. The purity of the dried glycine is 99.2%, and the content of chloride ions is 0.30%.
Reaction and crystallization: pumping 7.56kg of mother liquor into a reaction crystallizer by a pump, slowly adding 1.27kg of chloroacetic acid and 0.23kg of liquid ammonia into the reaction crystallizer, and controlling the reaction temperature to be between 15 and 20 ℃ and the pH to be between 6.5 and 7.0 in the whole process. As the reaction proceeded, the amount of white solid in the reactor gradually increased, and the reaction was completed after 1 hour. Pumping the reaction product in the reactor into a centrifugal machine by a pump, wherein the centrifugal speed is 10000rpm, the centrifugal time is 3min, and finally obtaining 1.44kg of crude ammonium chloride with solid content of 50%.
Recycling of circulating mother liquor: pumping 0.15kg of mother liquor into a circulating mother liquor recovery system by a pump, distilling to respectively obtain 0.10kg of methanol and 0.02kg of water, introducing liquid ammonia to precipitate 58.00g of a urotropine crude product with the solid content of 50%, and delivering the rest to a waste liquor system.
Example two:
preparation of circulating mother liquor: preparing a mixed solvent by using 12.10kg of methanol and 3.02kg of water, introducing 2.54kg of chloroacetic acid and 0.47kg of liquid ammonia, and controlling the reaction temperature to be between 10 and 15 ℃ and the pH to be between 6.5 and 7.0 in the whole process.
Ammoniation reaction: dissolving urotropine 0.10kg in water 0.06kg in a reaction kettle of a urotropine dosing tank, stirring for 15min, feeding into a urotropine raw material tank, and feeding into an ammoniation reactor through a pump; simultaneously, 0.24kg of methanol is supplemented from a methanol storage tank, and the methanol and 15.12kg of circulating mother liquor dissolved with 2.54kg of chloroacetic acid and 0.47kg of liquid ammonia react together in an ammoniation reactor. In an alcohol-water mixed solvent for ammoniation reaction, the mass percent of methanol is 80.0 percent; the reaction temperature is controlled to be 65-70 ℃, and the pH is controlled to be 6.8-7.1. As the reaction proceeded, the white solid in the reactor gradually increased and the reaction was complete after 40 min. After the reaction is finished, slowly cooling the reaction liquid to 20-25 degrees in three stages, and increasing crystallization; pumping the reaction product in the reactor into a centrifugal machine by a pump, wherein the centrifugal speed is 10000rpm, the centrifugal time is 2min, and finally obtaining 3.69kg of glycine, the solid content is 55 percent, and the yield of the glycine is 99.4 percent. The purity of the dried glycine is 99.3 percent, and the content of chloride ions is 0.27 percent.
Reaction and crystallization: pumping 15.12kg of mother liquor into a reaction crystallizer by a pump, slowly adding 2.54kg of chloroacetic acid and 0.47kg of liquid ammonia into the reaction crystallizer, and controlling the reaction temperature to be between 10 and 15 ℃ and the pH to be between 6.5 and 7.0 in the whole process. As the reaction proceeded, the amount of white solid in the reactor gradually increased, and the reaction was completed after 1 hour. Pumping the reaction product in the reactor into a centrifugal machine at 10000rpm for 3min to obtain 2.88kg of crude ammonium chloride product with solid content of 50%.
Recycling of circulating mother liquor: pumping 0.30kg of mother liquor into a circulating mother liquor recovery system by a pump, distilling to respectively obtain 0.20kg of methanol and 0.04kg of water, introducing liquid ammonia to precipitate 108.00g of a urotropine crude product with the solid content of 60%, and delivering the rest to a waste liquor system.
Example three:
circulating mother liquor: and mother liquor obtained by centrifugal separation in the reaction crystallization section in the second embodiment is used as circulating mother liquor to be continuously used for ammoniation reaction.
Ammoniation reaction: dissolving urotropine 0.10kg in water 0.06kg in a reaction kettle of a urotropine dosing tank, stirring for 15min, feeding into a urotropine raw material tank, and feeding into an ammoniation reactor through a pump; simultaneously, 0.24kg of methanol is supplemented from a methanol storage tank, and the methanol and 15.12kg of circulating mother liquor dissolved with 2.54kg of chloroacetic acid and 0.47kg of liquid ammonia react together in an ammoniation reactor. In an alcohol-water mixed solvent for ammoniation reaction, the mass percent of methanol is 80.0 percent; the reaction temperature is controlled to be 65-70 ℃, and the pH is controlled to be 6.8-7.1. As the reaction proceeded, the white solid in the reactor gradually increased and the reaction was complete after 40 min. After the reaction is finished, slowly cooling the reaction liquid to 20-25 degrees in three stages, and increasing crystallization; pumping the reaction product in the reactor into a centrifugal machine by a pump, wherein the centrifugal speed is 10000rpm, the centrifugal time is 2min, and finally obtaining 3.40kg of glycine, the solid content is 60 percent, and the yield of the glycine is 98.9 percent. The purity of the dried glycine is 99.1%, and the content of chloride ions is 0.32%.
Reaction and crystallization: pumping 15.12kg of mother liquor into a reaction crystallizer by a pump, slowly adding 2.54kg of chloroacetic acid and 0.47kg of liquid ammonia into the reaction crystallizer, and controlling the reaction temperature to be between 10 and 15 ℃ and the pH to be between 6.5 and 7.0 in the whole process. As the reaction proceeded, the amount of white solid in the reactor gradually increased, and the reaction was completed after 1 hour. Pumping the reaction product in the reactor into a centrifugal machine at 10000rpm for 3min to obtain 2.62kg of crude ammonium chloride product with solid content of 55%.
Recycling of circulating mother liquor: pumping 0.30kg of mother liquor into a circulating mother liquor recovery system by a pump, distilling to respectively obtain 0.20kg of methanol and 0.04kg of water, introducing liquid ammonia to precipitate 105.00g of a urotropine crude product with the solid content of 60%, and delivering the rest to a waste liquor system.
Example four:
circulating mother liquor: and taking the mother liquor obtained by centrifugal separation in the reaction crystallization section in the third embodiment as circulating mother liquor to be continuously used for ammoniation reaction.
Ammoniation reaction: dissolving urotropine 0.10kg in water 0.06kg in a reaction kettle of a urotropine dosing tank, stirring for 15min, feeding into a urotropine raw material tank, and feeding into an ammoniation reactor through a pump; simultaneously, 0.24kg of methanol is supplemented from a methanol storage tank, and the methanol and 15.12kg of circulating mother liquor dissolved with 2.54kg of chloroacetic acid and 0.47kg of liquid ammonia react together in an ammoniation reactor. In an alcohol-water mixed solvent for ammoniation reaction, the mass percent of methanol is 80.0 percent; the reaction temperature is controlled to be 65-70 ℃, and the pH is controlled to be 6.8-7.1. As the reaction proceeded, the white solid in the reactor gradually increased and the reaction was complete after 40 min. After the reaction is finished, slowly cooling the reaction liquid to 20-25 degrees in three stages, and increasing crystallization; pumping the reaction product in the reactor into a centrifugal machine by a pump, wherein the centrifugal speed is 10000rpm, the centrifugal time is 2min, and finally obtaining 3.90kg of glycine, the solid content is 52 percent, and the yield of the glycine is 99.5 percent. The purity of the dried glycine is 99.0 percent, and the content of chloride ions is 0.20 percent.
Reaction and crystallization: pumping 15.12kg of mother liquor into a reaction crystallizer by a pump, slowly adding 2.54kg of chloroacetic acid and 0.47kg of liquid ammonia into the reaction crystallizer, and controlling the reaction temperature to be between 10 and 15 ℃ and the pH to be between 6.5 and 7.0 in the whole process. As the reaction proceeded, the amount of white solid in the reactor gradually increased, and the reaction was completed after 1 hour. Pumping the reaction product in the reactor into a centrifugal machine at 10000rpm for 3min to obtain 2.88kg of crude ammonium chloride product with solid content of 50%.
Recycling of circulating mother liquor: pumping 0.30kg of mother liquor into a circulating mother liquor recovery system by a pump, distilling to respectively obtain 0.20kg of methanol and 0.04kg of water, introducing liquid ammonia to precipitate 113.00g of crude urotropine with the solid content of 55%, and delivering the rest to a waste liquor system.
Through the first to fourth examples, it can be seen that the separation of glycine and ammonium chloride is realized by adopting a mixed solvent and reaction crystallization mode; the method adopts the mother liquor circulation and continuous reaction mode, realizes the high-efficiency circulation continuous production of the glycine, improves the reaction efficiency, improves the product quality, is simple to operate, and is beneficial to the operation of technical personnel.
Another object of the present invention is to provide an apparatus for continuously preparing high-purity glycine by mother liquor circulation.
The above-mentioned apparatus includes: a chloroacetic acid ammoniation reaction system, a multi-stage cooling system, an ammonium chloride reaction crystallization system and a circulating mother liquor recovery system which are sequentially communicated; the chloroacetic acid ammonification reaction system comprises a raw material tank and an ammonification reactor, the ammonium chloride reaction crystallization system comprises a reaction crystallizer, a centrifuge, and the circulating mother liquor recovery system comprises a distillation tower, a crystallizer and an ammonification reactor.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. A method for continuously preparing high-purity glycine by mother liquor circulation is characterized in that: the method comprises the following steps:
1) circulating mother liquor returned from an ammonium chloride reaction crystallization system is supplemented with water, methanol and a urotropine catalyst; in an alcohol-water mixed solvent, ammonium chloroacetate reacts with liquid ammonia at a certain temperature and within a certain pH range to generate glycine which is crystallized and separated out;
2) after the ammoniation reaction is finished, the reaction liquid is slowly cooled in multiple stages, and the crystallization is increased; centrifugally separating out a solid glycine crude product, and simultaneously dissolving the byproduct ammonium chloride in the mother liquor;
3) step 2) enabling most of the circulating mother liquor dissolved with ammonium chloride to enter a reaction crystallizer, then simultaneously adding chloroacetic acid melt and liquid ammonia, controlling the temperature and the pH value within a certain range, carrying out centrifugal separation to obtain crude ammonium chloride, and returning the mother liquor to the reaction system in the step 1);
4) and 2) sequentially carrying out rectification, crystallization, ammoniation and other methods on a small part of circulating mother liquor dissolved with ammonium chloride to respectively recover methanol, ammonium chloride, urotropine and the like in the mother liquor, and sending residual liquid to wastewater treatment.
2. The method for continuously preparing high-purity glycine according to claim 1, wherein the mother liquor is recycled, and the method comprises the following steps: in the alcohol-water mixed solvent in the step 1), the mass percent of the methanol is 70-90%; the reaction temperature is 45-75 ℃; the reaction pH is controlled to be 6.3-7.5.
3. The method for continuously preparing high-purity glycine according to claim 1, wherein the mother liquor is recycled, and the method comprises the following steps: in the reaction system in the step 1), the mass ratio of the urotropine to the circulating mother liquor is 0.9-1.1: 14 to 16.
4. The method for continuously preparing high-purity glycine according to claim 1, wherein the mother liquor is recycled, and the method comprises the following steps: and 2) cooling the reaction liquid in the step 2) by adopting a 2-4-stage cooling crystallization reactor, and finally cooling to 15-25 ℃.
5. The method for continuously preparing high-purity glycine according to claim 1, wherein the mother liquor is recycled, and the method comprises the following steps: the reaction temperature in the step 3) is 10-20 ℃; the reaction pH is controlled to be 6.3-7.5.
6. The method for continuously preparing high-purity glycine according to claim 1, wherein the mother liquor is recycled, and the method comprises the following steps: the reaction crystallizer in the step 3) is a kettle type reactor.
7. The method for continuously preparing high-purity glycine according to claim 1, wherein the mother liquor is recycled, and the method comprises the following steps: the mass ratio of the chloroacetic acid melt to the circulating mother liquor replenished every time in the step 3) is as follows: 1: 5.5 to 10.5.
8. The method for continuously preparing high-purity glycine according to claim 1, wherein the mother liquor is recycled, and the method comprises the following steps: and 4) 1-3% of the circulating mother liquor enters a circulating mother liquor recovery system.
9. The method for continuously preparing high-purity glycine according to claim 1, wherein the mother liquor is recycled, and the method comprises the following steps: and 4) rectifying, cooling, crystallizing and ammoniating the circulating mother liquor to obtain methanol, ammonium chloride solid and urotropine solid in sequence.
10. The equipment for continuously preparing the high-purity glycine by using the method as claimed in claim 1 is characterized by comprising a chloroacetic acid ammoniation reaction system, a multi-stage cooling system, an ammonium chloride reaction crystallization system and a circulating mother liquor recovery system which are sequentially communicated; the chloroacetic acid ammonification reaction system comprises a raw material tank and an ammonification reactor which are sequentially communicated, the ammonium chloride reaction crystallization system comprises a reaction crystallizer and a centrifuge which are sequentially communicated, and the circulating mother liquor recovery system comprises a distillation tower, a crystallizer and an ammonification reactor which are sequentially communicated.
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| CN116178188A (en) * | 2022-12-28 | 2023-05-30 | 开封市隆兴化工有限公司 | One-step synthesis and step-by-step refining method for producing glycine in mixed solvent |
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