Environment-friendly glycine synthesis system

Abstract

The utility model discloses an environment-friendly glycine synthesis system and belongs to the technical field of glycine synthesis. Through arrangement of a crystallization kettle, a filter I, a filter II and the like and reasonable arrangement of a synthesis kettle, the crystallization kettle, the filter I, the filter II, electrodialysis, an alcohol precipitation kettle, a centrifugal machine, a chloroacetic acid preparation kettle and the like, reaction mother liquor is recycled and utilized orderly, effectively and stably, the yield of glycine is increased, meanwhile, the consumption of methanol is reduced, pollution discharge is reduced, and the production cost is reduced. The energy consumption is reduced, the environment-friendly synthesis of the glycine is realized, and the method is better matched with the synthesis process of the glycine.

Description

Technical Field

[0001] The utility model relates to an environment-friendly synthesis system of glycine, in particular to a glycine synthesis system based on electrodialysis technology and suitable for industrialization, belonging to the technical field of glycine synthesis. Background Art

[0002] Glycine, also known as aminoacetic acid, is an important fine chemical product, which is widely used in industries such as medicine, food, chemical industry, and pesticides. In medicine, it is mainly used in amino acid preparations, chlortetracycline buffer agents, and imidazole ethyl ester intermediates. In the food industry, it is used as a food additive for flavoring, sterilization and preservation, antioxidant, and nutritional fortification. In the pesticide industry, it is mainly used as a raw material for synthesizing glyphosate and glyphosine.

[0003] Industrial glycine is mostly produced by the ammonolysis method of chloroacetic acid. Among them, chloroacetic acid and liquid ammonia or ammonia water are used as raw materials, and hexamine is used as a catalyst. After the reaction, a mixture including glycine and ammonium chloride is obtained. Then, separation is carried out to obtain glycine products. Currently, the main separation methods involved are: First, the alcohol precipitation method. A large amount of methanol is added to the mixture of glycine and ammonium chloride. Through the solubility difference of glycine and ammonium chloride in methanol, glycine products are separated. Since the solubility of ammonium chloride in methanol is much lower than that in water, a large amount of methanol is required to separate glycine and ammonium chloride. Finally, glycine solid and a methanol solution containing a large amount of ammonium chloride and a small amount of glycine are obtained. In addition, a large amount of steam is required to recover methanol, resulting in high energy consumption. Second, the electrodialysis method. Electrodialysis is used to separate glycine and ammonium chloride. Although this reduces the usage amount of methanol, it also increases the power consumption.

[0004] Moreover, from the chemical reaction equation of synthesizing glycine, even if calculated at a 100% conversion rate, when a certain amount of glycine is generated, an equimolar amount of ammonium chloride will be generated. Eventually, whether using methanol to dissolve ammonium chloride to separate glycine or using the electrodialysis method to separate ammonium chloride in glycine, a large amount of energy - steam or electric energy from the outside is required to achieve separation.

[0005] Although the prior art CN109574864A discloses "a new process for synthesizing glycine", and CN107868015A discloses "a preparation method of a glycine and ammonium chloride mixed crystal", etc., in the separation and purification of glycine, there is also the problem of consuming a large amount of energy (steam or electric energy). Summary of the Invention

[0006] In order to solve the technical problems existing in the existing glycine synthesis process, such as low glycine yield, high methanol consumption, and high energy consumption, an environmentally friendly synthesis system for glycine is proposed. In this technical solution, through the settings of a crystallization kettle, a filter I, a filter II, etc., and the reasonable layout of a synthesis kettle, a crystallization kettle, a filter I, a filter II, an electrodialysis device, an alcohol precipitation kettle, a centrifuge, and a chloroacetic acid preparation kettle, the reaction mother liquor is recycled and utilized in an orderly, effective, and stable manner, improving the glycine yield. At the same time, the methanol consumption is reduced, the sewage discharge is reduced, and the energy consumption is reduced, etc., realizing the environmentally friendly synthesis of glycine and better cooperating with the glycine synthesis process.

[0007] In order to achieve the above technical objectives, the following technical solutions are proposed:

[0008] An environmentally friendly synthesis system for glycine, comprising a synthesis kettle, a crystallization kettle, a filter I, a filter II, a chloroacetic acid preparation kettle, an electrodialysis device, an alcohol precipitation kettle, and a centrifuge, wherein,

[0009] Synthesis kettle: Connected with a chloroacetic acid solution inlet pipe, an ammonia inlet pipe, and a catalyst inlet pipe, used for synthesizing glycine; the glycine reaction liquid outlet on the synthesis kettle is connected to the feed inlet on the crystallization kettle;

[0010] Crystallization kettle: Used to cool the glycine reaction liquid to facilitate the subsequent separation of the glycine reaction liquid by filter I; the discharge outlet on the crystallization kettle is connected to the feed inlet on filter I

[0011] Filter I: Connected with a washing liquid inlet pipe, the glycine solid outlet on filter I is connected to a glycine drying device, and the reaction mother liquor outlet on filter I is connected to the chloroacetic acid preparation kettle through a reaction mother liquor outlet pipe; Filter I is also connected to the feed inlet of the electrodialysis device through a glycine-ammonium chloride mixed solution outlet pipe, and the ammonium chloride solution outlet on the electrodialysis device is connected with an ammonium chloride solution outlet pipe. The glycine saturated solution outlet on the electrodialysis device is connected to filter I through a glycine saturated solution outlet pipe; A continuous path for ammonium chloride separation and recovery is formed among filter I, the glycine-ammonium chloride mixed solution outlet pipe, the electrodialysis device, and the ammonium chloride outlet pipe; A continuous path for glycine washing and enrichment is formed among filter I, the glycine-ammonium chloride mixed solution outlet pipe, the electrodialysis device, and the glycine saturated solution outlet pipe.

[0012] Among them, Filter I is used to separate the crystallized glycine reaction solution into glycine solids (containing ammonium chloride) and reaction mother liquor (including glycine and ammonium chloride). At the same time, the formed glycine solids are washed, and the formed glycine-ammonium chloride mixed solution is introduced into the electrodialysis device. Through electrodialysis, an ammonium chloride solution (salt) is formed and then recovered; a glycine saturated solution (acid) is also formed. Then, this glycine saturated solution is returned to Filter I. On the one hand, the recovery and enrichment of glycine are realized, and on the other hand, the glycine solids are washed to elute the ammonium chloride attached to the glycine solids. Then, through the continuous path treatment of ammonium chloride separation and recovery, glycine is enriched on the glycine solids, thereby increasing the yield of glycine, and this cycle continues. After long-term cyclic use of this washing process, or when it is necessary to stop the electrodialysis device for maintenance, the washing water (i.e., the small amount of glycine-ammonium chloride mixed solution) can be discharged into the alcohol precipitation kettle, that is, the glycine-ammonium chloride mixed solution outlet on Filter I is connected to the feed inlet of the alcohol precipitation kettle;

[0013] Chloroacetic acid preparation kettle: It is connected with a molten chloroacetic acid feed pipe. The chloroacetic acid preparation kettle is connected to the synthesis kettle through a chloroacetic acid solution inlet pipe. Filter II is arranged on the chloroacetic acid solution inlet pipe. The ammonium chloride solid outlet on Filter II is connected with an ammonium chloride solid outlet pipe; the reaction mother liquor outlet pipe is connected to Filter II through Branch Pipe I;

[0014] Alcohol precipitation kettle: It is connected with a methanol inlet pipe. The reaction mother liquor outlet pipe is connected to the alcohol precipitation kettle through Branch Pipe II; it is used to recover glycine again; the discharge outlet on the alcohol precipitation kettle is connected to a centrifuge;

[0015] Centrifuge: It is used to separate and recover glycine. The alcohol precipitation mother liquor outlet on the centrifuge is connected to a methanol recovery system, and the glycine solid outlet on the centrifuge is connected to a glycine drying device.

[0016] Furthermore, stirring mechanisms are provided in both Filter I and Filter II.

[0017] Furthermore, the glycine saturated solution outlet pipe is connected to the washing liquid inlet pipe.

[0018] Furthermore, the washing liquid inlet pipe is also connected with a deionized water inlet pipe I to wash the glycine in Filter I, improve the purity of glycine, and facilitate the subsequent recovery of glycine, thereby increasing the yield of glycine.

[0019] Furthermore, the electrodialysis device is connected with a deionized water inlet pipe II to ensure effective separation of the glycine-ammonium chloride mixed solution.

[0020] In this technical solution, the relationships of "above", "between", and "inside" are defined according to the actual usage situation, which are conventional terms in this technical field and also the conventional terms for those skilled in the art during actual use.

[0021] Adopting this technical solution, the beneficial technical effects are as follows:

[0022] 1) Through the specific arrangement of the synthesis kettle, crystallization kettle, filter I, filter II, chloroacetic acid preparation kettle and each pipeline, etc., the present utility model realizes the effective separation of glycine in the glycine reaction solution and improves its purity; at the same time, the reaction mother liquor is recycled in an orderly, effective and stable manner, improving the glycine yield. Meanwhile, the consumption of methanol is reduced, sewage discharge is reduced, and the environmental protection synthesis of glycine is realized; and, by reducing the working intensity of electrodialysis, the power consumption is further reduced, etc., and it is well coordinated with the glycine synthesis process;

[0023] 2) By recycling the reaction mother liquor, that is, no new deionized water is introduced in the preparation of the chloroacetic acid solution, the amount of mother liquor in the alcohol precipitation kettle is reduced, and thus the loss of glycine is also reduced. At the same time, it also requires less methanol than the existing synthesis system. Compared with the traditional glycine alcohol precipitation method, the glycine yield in this synthesis system is higher, up to 94 - 95%, and the consumption of methanol and steam is reduced by more than 1 / 2. Description of the Drawings

[0024] Figure 1 is the structural block diagram of the present utility model;

[0025] Figure 2 is the flow chart related to the present utility model;

[0026] In the figure, 1. synthesis kettle, 2. crystallization kettle, 3. filter I, 4. filter II, 5. electrodialysis device, 6. alcohol precipitation kettle, 7. centrifuge, 8. chloroacetic acid preparation kettle, 9. chloroacetic acid solution inlet pipe, 10. ammonia gas inlet pipe, 11. catalyst inlet pipe, 12. washing liquid inlet pipe, 13. glycine - ammonium chloride mixed solution outlet pipe, 14. ammonium chloride solution outlet pipe, 15. saturated glycine solution outlet pipe, 16. reaction mother liquor outlet pipe, 17. molten chloroacetic acid inlet pipe, 18. branch pipe I, 19. ammonium chloride solid outlet pipe, 20. methanol inlet pipe, 21. branch pipe II, 22. deionized water inlet pipe I, 23. deionized water inlet pipe II, 24. methanol recovery system, 25. glycine drying device. Detailed Embodiments

[0027] The technical solutions in the embodiments of the present utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

[0028] Embodiment 1

[0029] This embodiment provides an environmentally friendly synthesis system for glycine, as follows: Figure 1 As shown, it includes a synthesis kettle 1, a crystallization kettle 2, and a filter I 3 connected in sequence. The filter I 3 is connected to a washing liquid inlet pipe 12, and the glycine solid outlet on the filter I 3 is connected to a glycine drying device 25;

[0030] The glycine-ammonium chloride mixed solution outlet on the filter I 3 is connected to the feed inlet on the electrodialysis device 5 through a glycine-ammonium chloride mixed solution outlet pipe 13. The ammonium chloride solution outlet on the electrodialysis device 5 is connected to an ammonium chloride solution outlet pipe 14. The glycine saturated solution outlet on the electrodialysis device 5 is connected to the filter I 3 through a glycine saturated solution outlet pipe 15. A continuous path for ammonium chloride separation and recovery is formed among the filter I 3, the glycine-ammonium chloride mixed solution outlet pipe 13, the electrodialysis device 5, and the ammonium chloride outlet pipe; a continuous path for glycine washing and enrichment is formed among the filter I 3, the glycine-ammonium chloride mixed solution outlet pipe 13, the electrodialysis device 5, and the glycine saturated solution outlet pipe 15;

[0031] The reaction mother liquor outlet on the filter I 3 is connected to a chloroacetic acid preparation kettle 8 through a reaction mother liquor outlet pipe 16. The chloroacetic acid preparation kettle 8 is connected to a molten chloroacetic acid inlet pipe 17. The chloroacetic acid preparation kettle 8 is connected to the synthesis kettle 1 through a chloroacetic acid solution inlet pipe 9. A filter II 4 is provided on the chloroacetic acid solution inlet pipe 9. The reaction mother liquor outlet pipe 16 is connected to the filter II 4 through a branch pipe I 18. The ammonium chloride solid outlet on the filter II 4 is connected to an ammonium chloride solid outlet pipe 19. A continuous path for ammonium chloride separation and recovery is formed among the reaction mother liquor outlet pipe 16, the chloroacetic acid preparation kettle 8, the filter II 4, and the ammonium chloride solid outlet pipe; a continuous path for chloroacetic acid solution preparation and use is formed among the reaction mother liquor outlet pipe 16, the chloroacetic acid preparation kettle 8, the filter II 4, and the chloroacetic acid solution inlet pipe 9.

[0032] The involved working process includes:

[0033] In the preparation process of glycine, as follows: Figure 2 As shown, using chloroacetic acid and ammonia as raw materials and hexamine as a catalyst, after obtaining the glycine reaction solution, it is cooled, crystallized, and filtered to obtain a glycine-ammonium chloride solid mixture and a reaction mother liquor; deionized water / glycine saturated aqueous solution is added to the glycine-ammonium chloride solid mixture to pulp and wash the mixture; filtered to obtain the washing liquid of the glycine-ammonium chloride mixed solution; then, it enters the electrodialysis device, and under the action of an electric field and membrane interception, ammonium chloride and glycine saturated solution in the washing liquid are separated; the glycine saturated solution is reused as the washing liquid, that is, the glycine-ammonium chloride mixed solution is pulp-washed;

[0034] The reaction mother liquor obtained by crystallization and filtration of the glycine reaction solution is reused to prepare the chloroacetic acid solution. Based on the characteristics that chloroacetic acid is highly soluble in water and absorbs heat during dissolution, the raw material molten chloroacetic acid is added to the reaction mother liquor, which reduces the solubility of ammonium chloride in this system. Without increasing energy consumption, ammonium chloride precipitates and is separated. The prepared chloroacetic acid solution undergoes a reaction. Finally, the ratio of glycine to ammonium chloride in the reaction product is higher than that in the synthesis process of a single batch (i.e., without recycling the reaction mother liquor). For example, since there is no recycling of the reaction mother liquor in the single-batch batch reaction, calculated at a yield of 98%, when 1 mol of chloroacetic acid participates in the reaction, approximately 0.98 mol of glycine and 1 mol of ammonium chloride are generated. That is, before the reaction solution is cooled and crystallized in a single batch without recycling the reaction mother liquor, the molar ratio of glycine to ammonium chloride is 0.98:1. When the reaction mother liquor is recycled, approximately 20% of the ammonium chloride and glycine in the single-batch reaction solution will enter the next batch of chloroacetic acid solution. The chloroacetic acid solution consists of 1 mol of chloroacetic acid, 0.2 mol of ammonium chloride, and 0.196 mol of glycine. However, in the preparation of the chloroacetic acid solution in the present invention, part of the ammonium chloride is precipitated and removed. Therefore, there is less ammonium chloride in the chloroacetic acid solution entering the synthesis kettle, that is, the chloroacetic acid solution becomes composed of 1 mol of chloroacetic acid, 0.15 mol of ammonium chloride, and 0.196 mol of glycine. The newly added 1 mol of chloroacetic acid reacts to form 0.98 mol of glycine and 1 mol of ammonium chloride. When combined with the glycine and ammonium chloride introduced through the chloroacetic acid solution, the resulting reaction mother liquor contains 0.98 + 0.196 = 1.176 mol of glycine and 1 + 0.15 = 1.15 mol of ammonium chloride, that is, the molar ratio of glycine to ammonium chloride is 1.023:1, which is significantly higher than 0.98:1 in the single-batch reaction. At the same time, in the glycine-ammonium chloride solid obtained by crystallization, the proportion of glycine is higher, thus reducing the difficulty of subsequent separation.

[0035] The present invention provides an environmentally friendly synthesis system for glycine, which is preferably coordinated with the environmentally friendly synthesis process of glycine, specifically manifested as follows:

[0036] I. By cooling and crystallizing the glycine reaction solution, a glycine-ammonium chloride solid mixture and a reaction mother liquor are obtained, and then separated into a reaction mother liquor and glycine solid in a filter I with a pulping and washing function. The glycine solid does not directly undergo the next pulping and washing in this filter I, avoiding the cumbersome steps of unloading the glycine solid and then reintroducing it into the filter I for pulping and washing when using a conventional centrifuge subsequently, simplifying the steps and reducing the energy consumption during repeated feeding and discharging.

[0037] II. The glycine-ammonium chloride solid mixture (crystal) is connected to an electrodialysis device in Filter I with a pulping and washing function. The washing liquid enters Filter I, and the discharged washing water is a saturated aqueous solution of glycine-ammonium chloride. This saturated aqueous solution of glycine-ammonium chloride enters the electrodialysis device to separate out an ammonium chloride solution and a saturated aqueous solution of glycine. The saturated aqueous solution of glycine is recycled back to Filter I to continue washing the glycine-ammonium chloride solid mixture. Finally, glycine solid with the ammonium chloride content meeting the index requirements remains in Filter I and is discharged for drying. Without loss of glycine in the glycine-ammonium chloride solid mixture, qualified glycine products are obtained, with a higher yield compared to the traditional alcohol precipitation method;

[0038] III. The reaction mother liquor discharged from Filter I contains approximately 40% of the total amount of ammonium chloride generated by a single batch reaction. Half of the total amount of the reaction mother liquor is used for recycling, and among them, approximately 20% of the total amount of ammonium chloride generated by a single batch reaction is recycled with the reaction mother liquor. The recycled reaction mother liquor is used to prepare chloroacetic acid solution. Because chloroacetic acid has extremely strong hydrophilicity, after chloroacetic acid is dissolved in the reaction mother liquor in which ammonium chloride is in a saturated state, some ammonium chloride will precipitate. After detection, approximately 1 / 4 of the ammonium chloride in the recycled reaction mother liquor precipitates when preparing the chloroacetic acid solution, that is, the precipitated ammonium chloride accounts for approximately 5% of the total amount of ammonium chloride generated by a single batch reaction. And this 5% of the total amount of ammonium chloride generated by a single batch does not need to be dissolved by methanol and does not need to be separated by an electrodialysis device. Therefore, the separation energy consumption of ammonium chloride required in this synthesis process is 5% less than that in the traditional method;

[0039] IV. In the synthesis of glycine, part of the ammonium chloride generated by the ammoniation reaction is separated by an electrodialysis device, part is separated when preparing the chloroacetic acid solution, and the remaining part needs to be separated by adding methanol. Therefore, the amount of methanol required is greatly reduced compared to the method of separating glycine and ammonium chloride by the alcohol precipitation method for all glycine reaction solutions.

[0040] V. Since the reaction mother liquor is used to prepare the chloroacetic acid solution and no new deionized water is added to the chloroacetic acid, the total amount of wastewater discharged from this system will also be reduced.

[0041] Example 2

[0042] On the basis of Example 1, in order to further improve the glycine yield in this example, and when the washing water is recycled for a long time or when it is necessary to stop and repair the electrodialysis device 5, the washing water can be discharged into the alcohol precipitation kettle 6, specifically including:

[0043] An environmentally friendly synthesis system for glycine further includes an alcohol precipitation kettle 6 and a centrifuge 7. The glycine-ammonium chloride mixed solution outlet pipe 13 is connected to the upper feed inlet of the alcohol precipitation kettle 6, and the alcohol precipitation kettle 6 is connected with a methanol inlet pipe 20. The upper discharge outlet of the alcohol precipitation kettle 6 is connected to the centrifuge 7. The alcohol precipitation mother liquor outlet on the centrifuge 7 is connected with a methanol recovery system 24, and the glycine solid outlet on the centrifuge 7 is connected to a glycine drying device 25. A continuous path for glycine recovery is formed among the glycine-ammonium chloride mixed solution outlet pipe 13, the alcohol precipitation kettle 6 and the centrifuge 7.

[0044] Example 3

[0045] On the basis of Examples 1-2, in order to further improve the glycine yield in this example, further limitations are made:

[0046] The reaction mother liquor outlet pipe 16 is connected to the alcohol precipitation kettle 6 through a branch pipe II 21. A continuous path for glycine recovery is formed among the reaction mother liquor outlet pipe 16, the branch pipe II 21, the alcohol precipitation kettle 6 and the centrifuge 7.

[0047] Example 4

[0048] On the basis of Examples 1-3, in order to further improve the separation, washing efficiency and quality of the filter I 3, and improve the separation efficiency and quality of the filter II 4 in this example, further limitations are made:

[0049] Stirring mechanisms are provided inside both the filter I 3 and the filter II 4. Among them, the filter I 3 and the filter II 4 can adopt the tank type two-in-one filter of Hebei Dechuang Chemical Equipment Co., Ltd.

[0050] Example 5

[0051] On the basis of Examples 1-4, in order to further ensure the orderly and effective layout of each pipeline in this synthesis system in this example, further limitations are made:

[0052] The glycine saturated solution outlet pipe 15 is connected to the washing liquid inlet pipe 12, and the washing liquid inlet pipe 12 is also connected with a deionized water inlet pipe I 22. That is, during the first cycle between the filter I 3 and the electrodialysis device 5, deionized water is used as the washing liquid to wash the glycine reaction solution after cooling crystallization (after filtration); after separating ammonium chloride in the washing liquid under the action of an electric field and membrane interception, the remaining glycine saturated solution is reused for washing the glycine-ammonium chloride mixed solution.

[0053] Among them, the electrodialysis device 5 is connected with a deionized water inlet pipe II 23.

Claims

1. An environmentally friendly synthesis system for glycine, characterized in that: It comprises a synthesis kettle (1), a crystallization kettle (2) and a filter I (3) which are connected in sequence, and the filter I (3) is connected to a washing liquid inlet pipe (12); The glycine-ammonium chloride mixed solution outlet on the filter I (3) is connected to the upper feed port of the electrodialysis device (5) via the glycine-ammonium chloride mixed solution outlet pipe (13); the ammonium chloride solution outlet on the electrodialysis device (5) is connected to the ammonium chloride solution outlet pipe (14); the glycine saturated solution outlet on the electrodialysis device (5) is connected to the filter I (3) via the glycine saturated solution outlet pipe (15); a continuous passage for separating and recovering ammonium chloride is formed between the filter I (3), the glycine-ammonium chloride mixed solution outlet pipe (13), the electrodialysis device (5) and the ammonium chloride outlet pipe; A continuous passage for washing and enriching glycine is formed between the filter I (3), the glycine-ammonium chloride mixed solution outlet pipe (13), the electrodialysis device (5) and the glycine saturated solution outlet pipe (15); The reaction mother liquor outlet on the filter I (3) is connected to the chloroacetic acid preparation kettle (8) through the reaction mother liquor outlet pipe (16), and the chloroacetic acid preparation kettle (8) is connected to the molten chloroacetic acid inlet pipe (17); the chloroacetic acid preparation kettle (8) is connected to the synthesis kettle (1) through the chloroacetic acid solution inlet pipe (9), and the chloroacetic acid solution inlet pipe (9) is provided with a filter II (4), and the reaction mother liquor outlet pipe (16) is connected to the filter II (4) through the branch pipe I (18); the ammonium chloride solid outlet on the filter II (4) is connected to the ammonium chloride solid outlet pipe (19); a continuous passage for separating and recovering ammonium chloride is formed between the reaction mother liquor outlet pipe (16), the chloroacetic acid preparation kettle (8), the filter II (4) and the ammonium chloride solid outlet pipe (19); and a continuous passage for preparing and using the chloroacetic acid solution is formed between the reaction mother liquor outlet pipe (16), the chloroacetic acid preparation kettle (8), the filter II (4) and the chloroacetic acid solution inlet pipe (9).

2. The environmentally friendly synthesis system of glycine according to claim 1, characterized in that: The glycine solid outlet on the filter I (3) is connected to a glycine drying device (25).

3. The environmentally friendly synthesis system of glycine according to claim 1 or 2, characterized in that: The system further comprises an alcohol analysis kettle (6) and a centrifuge (7); the glycine-ammonium chloride mixed solution outlet pipe (13) is connected to the upper feed port of the alcohol analysis kettle (6); the alcohol analysis kettle (6) is connected to a methanol inlet pipe (20); the upper discharge port of the alcohol analysis kettle (6) is connected to the centrifuge (7); the alcohol analysis mother liquor outlet on the centrifuge (7) is connected to a methanol recovery system (24); the glycine solid outlet on the centrifuge (7) is connected to a glycine drying device (25); and a continuous passage for glycine recovery is formed between the glycine-ammonium chloride mixed solution outlet pipe (13), the alcohol analysis kettle (6) and the centrifuge (7).

4. The environmentally friendly synthesis system of glycine according to claim 3, characterized in that: The reaction mother liquor outlet pipe (16) is connected to the alcohol separation kettle (6) via a branch pipe II (21), and a continuous passage for recovering glycine is formed between the reaction mother liquor outlet pipe (16), the branch pipe II (21), the alcohol separation kettle (6) and the centrifuge (7).

5. The environmentally friendly synthesis system of glycine according to claim 1, characterized in that: The filter I (3) and the filter II (4) are both provided with a stirring mechanism.

6. The environmentally friendly synthesis system of glycine according to claim 1, characterized in that: The glycine saturated solution outlet pipe (15) is connected to the washing liquid inlet pipe (12).

7. The environmentally friendly synthesis system of glycine according to claim 6, characterized in that: The washing liquid inlet pipe (12) is also connected to a deionized water inlet pipe I (22).

8. The environmentally friendly synthesis system of glycine according to claim 1, characterized in that: The electrodialysis device (5) is connected to a deionized water inlet pipe II (23).

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