A system for continuous synthesis of glycine

Abstract

The utility model discloses a kind of systems for continuous synthesis glycine, it is related to glycine preparation technical field, first stage reaction kettle, second stage reaction kettle, third stage reaction kettle and fourth stage reaction kettle cascade use, obtain glycine reaction liquid (including hexamine, glycine and ammonium chloride etc.) by four times of reaction, glycine reaction liquid is entered first low-temperature crystallization kettle or second low-temperature crystallization kettle by reaction liquid inlet pipe, glycine reaction liquid is cooled crystallization in first low-temperature crystallization kettle or second low-temperature crystallization kettle, after crystallization is finished, it is entered first centrifuge by first connecting pipe or second connecting pipe and carries out centrifugal treatment, and mother liquor and mixed crystal wet product are obtained by centrifugation, and mixed crystal wet product is discharged by mixed crystal outlet pipe;Mother liquor is flowed back first stage reaction kettle and / or third stage reaction kettle by hexamine solution inlet pipe and / or second discharge pipe and is reused.

Description

Technical Field

[0001] This invention belongs to the field of glycine preparation technology, specifically relating to a system for continuous synthesis of glycine. Background Technology

[0002] Glycine has a wide range of applications in the chemical, pesticide, pharmaceutical, food, and feed industries. Depending on the raw materials used, glycine production processes can be categorized into the chloroacetic acid ammonolysis method, the Strecker process, and the Hein process. Because chloroacetic acid is widely available, the chloroacetic acid ammonolysis method is commonly used in domestic glycine production. This process begins with chloroacetic acid reacting with ammonia under the catalysis of hexamethylenetetramine to produce a mixture of glycine and ammonium chloride. Then, taking advantage of the different solubilities of glycine and ammonium chloride in methanol-water solutions, methanol is used to crystallize the glycine. Finally, the wet glycine is separated by centrifugation and dried to obtain the finished glycine. The methanol mother liquor separated by centrifugation is distilled back to obtain methanol with a certain water content for reuse, allowing the ammonium chloride dissolved in the methanol to precipitate. This method achieves the separation of glycine and ammonium chloride, but the separation process of the product glycine and the byproduct ammonium chloride has high energy consumption, accounting for approximately 80% of the entire existing glycine production process. Furthermore, the separated glycine product still contains some ammonium chloride. The chloride ion content in the glycine product directly determines its quality grade.

[0003] In order to reduce the ammonium chloride content in glycine products and ultimately improve product quality, existing technologies typically involve repeated recrystallization of glycine products. This not only increases energy consumption but also results in some product being lost with the mother liquor during repeated recrystallization, leading to a significant reduction in product yield.

[0004] Chinese patent CN115124436A, published on September 30, 2022, discloses a continuous production process for glycine. Chloroacetic acid and hexamethylenetetramine are dissolved in water, and then ammonia gas is introduced to carry out an ammoniation reaction, yielding a mixed solution. The mixed solution is cooled and crystallized, then centrifuged to obtain a stock solution and crystals. The stock solution undergoes a first-stage electrodialysis treatment to obtain a first-stage dialysis solution and an organic liquid. The crystals are added to a saturated glycine solution for mixing and dissolution, and then centrifuged to obtain a glycine product and a saturated solution. The saturated solution undergoes a second-stage electrodialysis treatment to obtain a second-stage dialysis solution and a saturated organic liquid. The first-stage and second-stage dialysis solutions are evaporated to obtain ammonium chloride and water. This method involves a complex production system and has high production costs. Utility Model Content

[0005] To solve the above-mentioned technical problems, this utility model provides a system for the continuous synthesis of glycine. Urotropin solution, chloroacetic acid, and ammonia are added to a first-stage reactor through a urotropin solution inlet pipe, a first chloroacetic acid inlet pipe, and a first ammonia inlet pipe, respectively, for the first reaction. After the first reaction, the mixture flows into a second-stage reactor through a first feed pipe, and chloroacetic acid and ammonia are added to the second-stage reactor through a second chloroacetic acid inlet pipe and a second ammonia inlet pipe for the second reaction. After the second reaction, the mixture flows into a third-stage reactor through a second feed pipe, and chloroacetic acid and ammonia are added to the third-stage reactor through a third chloroacetic acid inlet pipe and a third ammonia inlet pipe for the third reaction. After the third reaction, the product flows into the fourth-stage reactor through the third feed pipe, and ammonia is added through the fourth ammonia inlet pipe to carry out the fourth reaction, resulting in a glycine reaction solution. The glycine reaction solution enters the first or second low-temperature crystallization vessel through the reaction solution inlet pipe. The glycine reaction solution is cooled and crystallized in the first or second low-temperature crystallization vessel. After crystallization, it enters the first centrifuge through the first or second connecting pipe for centrifugation. Centrifugation yields mother liquor and mixed crystal wet product. The mixed crystal wet product is discharged through the mixed crystal outlet pipe. The mother liquor flows back to the first and / or third-stage reactors for reuse through the hexamethylenetetramine solution inlet pipe and / or the second feed pipe.

[0006] The objective of this utility model is achieved through the following technical solution: A system for continuous synthesis of glycine includes a first-stage reactor equipped with a hexamethylenetetramine solution inlet, a first chloroacetic acid inlet, a first ammonia inlet, and a first discharge pipe. The first discharge pipe is connected to a second-stage reactor, which is equipped with a second chloroacetic acid inlet, a second ammonia inlet, and a second discharge pipe. The second discharge pipe is connected to a third-stage reactor equipped with a third chloroacetic acid inlet, a third ammonia inlet, and a third discharge pipe. The third discharge pipe is connected to a fourth-stage reactor equipped with a fourth ammonia inlet and a fourth discharge pipe. The fourth discharge pipe is connected to a first low-temperature crystallization vessel and a second low-temperature crystallization vessel. The first low-temperature crystallization vessel is connected to a centrifuge via a first connecting pipe, and the second low-temperature crystallization vessel is connected to a centrifuge via a second connecting pipe. The centrifuge is equipped with a mother liquor outlet and a mixed crystal outlet. The mother liquor outlet is connected to the hexamethylenetetramine solution inlet and / or the second discharge pipe.

[0007] Preferably, the first ammonia inlet pipe, the second ammonia inlet pipe, the third ammonia inlet pipe and the fourth ammonia inlet pipe are all connected to the main ammonia inlet pipe.

[0008] Preferably, the first-stage reactor and the second-stage reactor are arranged on the same horizontal plane, and the third-stage reactor and the fourth-stage reactor are arranged on the same horizontal plane.

[0009] Preferably, the installation planes of the first-stage and second-stage reactors are higher than the installation planes of the third-stage and fourth-stage reactors.

[0010] Preferably, the first-stage reactor, the second-stage reactor, the third-stage reactor, and the fourth-stage reactor are respectively provided with a first tail gas outlet pipe, a second tail gas outlet pipe, a third tail gas outlet pipe, and a fourth tail gas outlet pipe.

[0011] Preferably, the mother liquor outlet pipe is connected to the mother liquor storage tank, the mother liquor storage tank is connected to the first mother liquor return pipe, the first mother liquor return pipe is equipped with a mother liquor return pump, a second mother liquor return pipe and a third mother liquor return pipe, and the second mother liquor return pipe is connected to the second discharge pipe.

[0012] Preferably, the third mother liquor reflux pipe is connected to the hexamethylenetetramine solution inlet pipe.

[0013] Preferably, the third mother liquor reflux pipe is connected to the hexamethylenetetramine dissolving vessel, the hexamethylenetetramine dissolving vessel is connected to the catalyst storage tank via the third connecting pipe, the catalyst storage tank is connected via the fourth connecting pipe, and the fourth connecting pipe is connected to the hexamethylenetetramine solution inlet pipe.

[0014] Preferably, each of the following pipes is equipped with a feed valve: hexamethylenetetramine solution inlet pipe, first chloroacetic acid inlet pipe, first ammonia inlet pipe, first discharge pipe, second chloroacetic acid inlet pipe, second ammonia inlet pipe, second discharge pipe, third chloroacetic acid inlet pipe, third ammonia inlet pipe, third discharge pipe, fourth ammonia inlet pipe, fourth discharge pipe, first connecting pipe, second connecting pipe, mother liquor outlet pipe, mixed crystal outlet pipe, first tail gas outlet pipe, second tail gas outlet pipe, third tail gas outlet pipe, fourth tail gas outlet pipe, first mother liquor reflux pipe, second mother liquor reflux pipe, third mother liquor reflux pipe, and fourth connecting pipe.

[0015] Preferably, flow meters are installed on the hexamethylenetetramine solution inlet pipe, the first chloroacetic acid inlet pipe, the first ammonia inlet pipe, the second chloroacetic acid inlet pipe, the second ammonia inlet pipe, the third chloroacetic acid inlet pipe, the third ammonia inlet pipe, and the fourth ammonia inlet pipe.

[0016] The beneficial effects of this technical solution are as follows: I. This utility model provides a system for the continuous synthesis of glycine. Urotropin solution, chloroacetic acid, and ammonia are added to a first-stage reactor through a urotropin solution inlet pipe, a first chloroacetic acid inlet pipe, and a first ammonia inlet pipe, respectively, for a first reaction. After the first reaction, the mixture flows into a second-stage reactor through a first feed pipe, and chloroacetic acid and ammonia are added to the second-stage reactor through a second chloroacetic acid inlet pipe and a second ammonia inlet pipe for a second reaction. After the second reaction, the mixture flows into a third-stage reactor through a second feed pipe, and chloroacetic acid and ammonia are added to the third-stage reactor through a third chloroacetic acid inlet pipe and a third ammonia inlet pipe for a third reaction. After the third ... so on. The feed stream flows into the fourth-stage reactor through the third feed pipe, and ammonia gas is added through the fourth ammonia inlet pipe to carry out the fourth reaction, obtaining a glycine reaction solution (including hexamethylenetetramine, glycine, and ammonium chloride, etc.). The glycine reaction solution enters the first or second low-temperature crystallization vessel through the reaction solution inlet pipe. The glycine reaction solution is cooled and crystallized in the first or second low-temperature crystallization vessel. After crystallization, it enters the first centrifuge through the first or second connecting pipe for centrifugation. Centrifugation yields mother liquor and mixed crystal wet product. The mixed crystal wet product is discharged through the mixed crystal outlet pipe. The mother liquor flows back to the first and / or third-stage reactors for reuse through the hexamethylenetetramine solution inlet pipe and / or the second feed pipe.

[0017] II. This utility model provides a continuous synthesis system for glycine. The first and second stage reactors are arranged on the same horizontal plane, as are the third and fourth stage reactors. The installation horizontal planes of the first and second stage reactors are higher than those of the third and fourth stage reactors. After the first stage reaction, the material is directly discharged into the second stage reactor through the first discharge pipe. The second discharge pipe is an overflow pipe. When the material in the second stage reactor reaches the overflow port connected to the second discharge pipe, it is discharged into the third stage reactor through the second discharge pipe. After the third stage reaction, the material is directly discharged into the fourth stage reactor through the third discharge pipe. When the material in the fourth stage reactor reaches the overflow port connected to the fourth discharge pipe, it is discharged into either the first or second low-temperature crystallization reactor through the fourth discharge pipe. This ensures a more complete reaction.

[0018] III. The present invention provides a system for continuous synthesis of glycine, wherein the first-stage reactor, the second-stage reactor, the third-stage reactor, and the fourth-stage reactor are discharged through the first tail gas outlet pipe, the second tail gas outlet pipe, the third tail gas outlet pipe, and the fourth tail gas outlet pipe.

[0019] IV. The present invention provides a system for continuous synthesis of glycine, wherein the setting of the hexamethylenetetramine dissolving vessel allows hexamethylenetetramine to be added through the feed inlet above the hexamethylenetetramine dissolving vessel when the concentration of the hexamethylenetetramine solution is insufficient. Attached Figure Description

[0020] Figure 1This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the structure of Embodiment 3 of this utility model; The reactor consists of: 1. First-stage reactor; 2. Hexamethylenetetramine solution inlet pipe; 3. First chloroacetic acid inlet pipe; 4. First ammonia inlet pipe; 5. First feed pipe; 6. Second-stage reactor; 7. Second chloroacetic acid inlet pipe; 8. Second ammonia inlet pipe; 9. Second feed pipe; 10. Third-stage reactor; 11. Third chloroacetic acid inlet pipe; 12. Third ammonia inlet pipe; 13. Third feed pipe; 14. Fourth-stage reactor; 15. Fourth ammonia inlet pipe; 16. Fourth feed pipe; 17. First low-temperature crystallization reactor; 18. Second low-temperature crystallization reactor; 19. First connecting pipe. 20. Centrifuge; 21. Second connecting pipe; 22. Mother liquor outlet pipe; 23. Mixed crystal outlet pipe; 24. Ammonia gas inlet main pipe; 25. First tail gas outlet pipe; 26. Second tail gas outlet pipe; 27. Third tail gas outlet pipe; 28. Fourth tail gas outlet pipe; 29. ​​Mother liquor storage tank; 30. First mother liquor reflux pipe; 31. Mother liquor reflux pump; 32. Second mother liquor reflux pipe; 33. Third mother liquor reflux pipe; 34. Hexamethylenetetramine dissolving vessel; 35. Third connecting pipe; 36. Catalyst storage tank; 37. Fourth connecting pipe; 38. Feed valve; 39. Flow meter. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0022] Example 1 like Figure 1 As shown, a system for the continuous synthesis of glycine includes a first-stage reactor 1. The first-stage reactor 1 is equipped with a hexamethylenetetramine solution inlet pipe 2, a first chloroacetic acid inlet pipe 3, a first ammonia inlet pipe 4, and a first discharge pipe 5. The first discharge pipe 5 is connected to a second-stage reactor 6. The second-stage reactor 6 is equipped with a second chloroacetic acid inlet pipe 7, a second ammonia inlet pipe 8, and a second discharge pipe 9. The second discharge pipe 9 is connected to a third-stage reactor 10. The third-stage reactor 10 is equipped with a third chloroacetic acid inlet pipe 11, a third ammonia inlet pipe 12, and a third discharge pipe 13. The third feed pipe 13 is connected to the fourth stage reactor 14. The fourth stage reactor 14 is equipped with a fourth ammonia inlet pipe 15 and a fourth feed pipe 16. The fourth feed pipe 16 is connected to the first low-temperature crystallization reactor 17 and the second low-temperature crystallization reactor 18. The first low-temperature crystallization reactor 17 is connected to the centrifuge 20 through a first connecting pipe 19. The second low-temperature crystallization reactor 18 is connected to the centrifuge 20 through a second connecting pipe 21. The centrifuge 20 is equipped with a mother liquor outlet pipe 22 and a mixed crystal outlet pipe 23. The mother liquor outlet pipe 22 is connected to the hexamethylenetetramine solution inlet pipe 2 and / or the second feed pipe 9.

[0023] Example 2 A system for continuous synthesis of glycine includes a first-stage reactor 1, which is equipped with a hexamethylenetetramine solution inlet 2, a first chloroacetic acid inlet 3, a first ammonia inlet 4, and a first feed pipe 5. The first feed pipe 5 is connected to a second-stage reactor 6, which is equipped with a second chloroacetic acid inlet 7, a second ammonia inlet 8, and a second feed pipe 9. The second feed pipe 9 is connected to a third-stage reactor 10, which is equipped with a third chloroacetic acid inlet 11, a third ammonia inlet 12, and a third feed pipe 13. The feed pipe 13 is connected to the fourth-stage reactor 14. The fourth-stage reactor 14 is equipped with a fourth ammonia inlet pipe 15 and a fourth feed pipe 16. The fourth feed pipe 16 is connected to the first low-temperature crystallization reactor 17 and the second low-temperature crystallization reactor 18. The first low-temperature crystallization reactor 17 is connected to the centrifuge 20 through a first connecting pipe 19. The second low-temperature crystallization reactor 18 is connected to the centrifuge 20 through a second connecting pipe 21. The centrifuge 20 is equipped with a mother liquor outlet pipe 22 and a mixed crystal outlet pipe 23. The mother liquor outlet pipe 22 is connected to the hexamethylenetetramine solution inlet pipe 2 and / or the second feed pipe 9.

[0024] The first ammonia inlet pipe 4, the second ammonia inlet pipe 8, the third ammonia inlet pipe 12 and the fourth ammonia inlet pipe 15 are all connected to the ammonia inlet main pipe 24.

[0025] The first-stage reactor 1 and the second-stage reactor 6 are arranged on the same horizontal plane, and the third-stage reactor 10 and the fourth-stage reactor 14 are arranged on the same horizontal plane.

[0026] The installation planes of the first-stage reactor 1 and the second-stage reactor 6 are higher than the installation planes of the third-stage reactor 10 and the fourth-stage reactor 14.

[0027] The first stage reactor 1, the second stage reactor 6, the third stage reactor 10 and the fourth stage reactor 14 are respectively equipped with a first tail gas outlet pipe 25, a second tail gas outlet pipe 26, a third tail gas outlet pipe 27 and a fourth tail gas outlet pipe 28.

[0028] The mother liquor outlet pipe 22 is connected to the mother liquor storage tank 29, the mother liquor storage tank 29 is connected to the first mother liquor return pipe 30, the first mother liquor return pipe 30 is equipped with a mother liquor return pump 31, a second mother liquor return pipe 32 and a third mother liquor return pipe 33, and the second mother liquor return pipe 32 is connected to the second discharge pipe 9.

[0029] The third mother liquor reflux pipe 33 is connected to the hexamethylenetetramine solution inlet pipe 2.

[0030] Example 3 like Figure 2As shown, a system for the continuous synthesis of glycine includes a first-stage reactor 1. The first-stage reactor 1 is equipped with a hexamethylenetetramine solution inlet pipe 2, a first chloroacetic acid inlet pipe 3, a first ammonia inlet pipe 4, and a first discharge pipe 5. The first discharge pipe 5 is connected to a second-stage reactor 6. The second-stage reactor 6 is equipped with a second chloroacetic acid inlet pipe 7, a second ammonia inlet pipe 8, and a second discharge pipe 9. The second discharge pipe 9 is connected to a third-stage reactor 10. The third-stage reactor 10 is equipped with a third chloroacetic acid inlet pipe 11, a third ammonia inlet pipe 12, and a third discharge pipe 13. The third feed pipe 13 is connected to the fourth stage reactor 14. The fourth stage reactor 14 is equipped with a fourth ammonia inlet pipe 15 and a fourth feed pipe 16. The fourth feed pipe 16 is connected to the first low-temperature crystallization reactor 17 and the second low-temperature crystallization reactor 18. The first low-temperature crystallization reactor 17 is connected to the centrifuge 20 through a first connecting pipe 19. The second low-temperature crystallization reactor 18 is connected to the centrifuge 20 through a second connecting pipe 21. The centrifuge 20 is equipped with a mother liquor outlet pipe 22 and a mixed crystal outlet pipe 23. The mother liquor outlet pipe 22 is connected to the hexamethylenetetramine solution inlet pipe 2 and / or the second feed pipe 9.

[0031] The first ammonia inlet pipe 4, the second ammonia inlet pipe 8, the third ammonia inlet pipe 12 and the fourth ammonia inlet pipe 15 are all connected to the ammonia inlet main pipe 24.

[0032] The first-stage reactor 1 and the second-stage reactor 6 are arranged on the same horizontal plane, and the third-stage reactor 10 and the fourth-stage reactor 14 are arranged on the same horizontal plane.

[0033] The installation planes of the first-stage reactor 1 and the second-stage reactor 6 are higher than the installation planes of the third-stage reactor 10 and the fourth-stage reactor 14.

[0034] The first stage reactor 1, the second stage reactor 6, the third stage reactor 10 and the fourth stage reactor 14 are respectively equipped with a first tail gas outlet pipe 25, a second tail gas outlet pipe 26, a third tail gas outlet pipe 27 and a fourth tail gas outlet pipe 28.

[0035] The mother liquor outlet pipe 22 is connected to the mother liquor storage tank 29, the mother liquor storage tank 29 is connected to the first mother liquor return pipe 30, the first mother liquor return pipe 30 is equipped with a mother liquor return pump 31, a second mother liquor return pipe 32 and a third mother liquor return pipe 33, and the second mother liquor return pipe 32 is connected to the second discharge pipe 9.

[0036] The third mother liquor reflux pipe 33 is connected to the hexamethylenetetramine dissolving vessel 34, the hexamethylenetetramine dissolving vessel 34 is connected to the catalyst storage tank 36 through the third connecting pipe 35, the catalyst storage tank 36 is connected through the fourth connecting pipe 37, and the fourth connecting pipe 37 is connected to the hexamethylenetetramine solution inlet pipe 2.

[0037] Among them, the hexamethylenetetramine solution inlet pipe 2, the first chloroacetic acid inlet pipe 3, the first ammonia inlet pipe 4, the first discharge pipe 5, the second chloroacetic acid inlet pipe 7, the second ammonia inlet pipe 8, the second discharge pipe 9, the third chloroacetic acid inlet pipe 11, the third ammonia inlet pipe 12, the third discharge pipe 13, the fourth ammonia inlet pipe 15, the fourth discharge pipe 16, the first connecting pipe 19, the second connecting pipe 21, the mother liquor outlet pipe 22, the mixed crystal outlet pipe 23, the first tail gas outlet pipe 25, the second tail gas outlet pipe 26, the third tail gas outlet pipe 27, the fourth tail gas outlet pipe 28, the first mother liquor reflux pipe 30, the second mother liquor reflux pipe 32, the third mother liquor reflux pipe 33, and the fourth connecting pipe 37 are all equipped with feed valves 38.

[0038] Flow meters 39 are installed on the hexamethylenetetramine solution inlet pipe 2, the first chloroacetic acid inlet pipe 3, the first ammonia inlet pipe 4, the second chloroacetic acid inlet pipe 7, the second ammonia inlet pipe 8, the third chloroacetic acid inlet pipe 11, the third ammonia inlet pipe 12, and the fourth ammonia inlet pipe 15.

[0039] Among them, the first-stage reactor 1, the second-stage reactor 6, the third-stage reactor 10, the fourth-stage reactor 14, the first low-temperature crystallization reactor 17, the second low-temperature crystallization reactor 18, the centrifuge 20, the mother liquor storage tank 29, the mother liquor reflux pump 31, the hexamethylenetetramine dissolving vessel 34, the catalyst storage tank 36, the feed valve 38, and the flow meter 39 are all existing technologies and will not be described in detail here.

[0040] The beneficial effects of this technical solution are as follows: I. This utility model provides a system for the continuous synthesis of glycine. Urotropin solution, chloroacetic acid, and ammonia are added to a first-stage reactor 1 via urotropin solution inlet 2, first chloroacetic acid inlet 3, and first ammonia inlet 4, respectively, for a first reaction. After the first reaction, the mixture flows into a second-stage reactor 6 via a first feed pipe 5, and chloroacetic acid and ammonia are added to the second-stage reactor 6 via a second chloroacetic acid inlet 7 and a second ammonia inlet 8 for a second reaction. After the second reaction, the mixture flows into a third-stage reactor 10 via a second feed pipe 9, and chloroacetic acid and ammonia are added to the third-stage reactor 10 via a third chloroacetic acid inlet 11 and a third ammonia inlet 12 for a third reaction. After the third reaction, the mixture flows into a fourth-stage reactor 14 via a third feed pipe 13, and ammonia is added to the fourth ammonia inlet 15. The gas undergoes a fourth reaction to obtain a glycine reaction solution (including hexamethylenetetramine, glycine, and ammonium chloride, etc.). The glycine reaction solution enters the first low-temperature crystallization vessel 17 or the second low-temperature crystallization vessel 18 through the reaction solution inlet pipe. The glycine reaction solution is cooled and crystallized in the first low-temperature crystallization vessel 17 or the second low-temperature crystallization vessel 18. After crystallization, it enters the first centrifuge 20 through the first connecting pipe 19 or the second connecting pipe 21 for centrifugation. Centrifugation yields a mother liquor (including hexamethylenetetramine, glycine, and ammonium chloride, etc.) and a mixed crystal wet product (including glycine and ammonium chloride, etc.). The mixed crystal wet product is discharged through the mixed crystal outlet pipe 23 (the mixed crystal wet product can be further separated and dried to obtain the glycine product). The mother liquor flows back to the first-stage reactor 1 and / or the third-stage reactor 10 for reuse through the hexamethylenetetramine solution inlet pipe 2 and / or the second discharge pipe 9.

[0041] II. This utility model provides a continuous synthesis system for glycine. The first-stage reactor 1 and the second-stage reactor 6 are arranged on the same horizontal plane, as are the third-stage reactor 10 and the fourth-stage reactor 14. The installation horizontal planes of the first-stage reactor 1 and the second-stage reactor 6 are higher than those of the third-stage reactor 10 and the fourth-stage reactor 14. After the first-stage reaction, the material is directly discharged into the second-stage reactor 6 through the first discharge pipe 5. The second discharge pipe 9 is an overflow pipe. When the material in the second-stage reactor 6 reaches the overflow port connected to the second discharge pipe 9, it is discharged into the third-stage reactor 10 through the second discharge pipe 9. After the third-stage reaction, the material is directly discharged into the fourth-stage reactor 14 through the third discharge pipe 13. When the material in the fourth-stage reactor 14 reaches the overflow port connected to the fourth discharge pipe 16, it is discharged into the first low-temperature crystallization vessel 17 or the second low-temperature crystallization vessel 18 through the fourth discharge pipe 16. This ensures a more complete reaction.

[0042] III. The present invention provides a system for continuous synthesis of glycine, wherein the first-stage reactor 1, the second-stage reactor 6, the third-stage reactor 10 and the fourth-stage reactor 14 are discharged through the first tail gas outlet pipe 25, the second tail gas outlet pipe 26, the third tail gas outlet pipe 27 and the fourth tail gas outlet pipe 28.

[0043] IV. The present invention provides a system for continuous synthesis of glycine, wherein the urotropine dissolving vessel 34 is configured so that urotropine can be added through the feed inlet above the urotropine dissolving vessel 34 when the concentration of the urotropine solution is insufficient.

[0044] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A system for the continuous synthesis of glycine, characterized in that: The reactor includes a first-stage reactor (1), which is equipped with a hexamethylenetetramine solution inlet pipe (2), a first chloroacetic acid inlet pipe (3), a first ammonia inlet pipe (4), and a first discharge pipe (5). The first discharge pipe (5) is connected to a second-stage reactor (6). The second-stage reactor (6) is equipped with a second chloroacetic acid inlet pipe (7), a second ammonia inlet pipe (8), and a second discharge pipe (9). The second discharge pipe (9) is connected to a third-stage reactor (10). The third-stage reactor (10) is equipped with a third chloroacetic acid inlet pipe (11), a third ammonia inlet pipe (12), and a third discharge pipe (13). The third discharge pipe (13) is connected to the first stage reactor (6). The fourth stage reactor (14) is connected to the fourth stage reactor (14), which is equipped with a fourth ammonia inlet pipe (15) and a fourth discharge pipe (16). The fourth discharge pipe (16) is connected to the first low-temperature crystallization reactor (17) and the second low-temperature crystallization reactor (18). The first low-temperature crystallization reactor (17) is connected to the centrifuge (20) through the first connecting pipe (19). The second low-temperature crystallization reactor (18) is connected to the centrifuge (20) through the second connecting pipe (21). The centrifuge (20) is equipped with a mother liquor outlet pipe (22) and a mixed crystal outlet pipe (23). The mother liquor outlet pipe (22) is connected to the hexamethylenetetramine solution inlet pipe (2) and / or the second discharge pipe (9).

2. The system for continuous synthesis of glycine according to claim 1, characterized in that: The first ammonia inlet pipe (4), the second ammonia inlet pipe (8), the third ammonia inlet pipe (12) and the fourth ammonia inlet pipe (15) are all connected to the ammonia inlet main pipe (24).

3. The system for continuous synthesis of glycine according to claim 2, characterized in that: The first-stage reactor (1) and the second-stage reactor (6) are set on the same horizontal plane, and the third-stage reactor (10) and the fourth-stage reactor are set on the same horizontal plane.

4. The system for continuous synthesis of glycine according to claim 3, characterized in that: The installation planes of the first-stage reactor (1) and the second-stage reactor (6) are higher than the installation planes of the third-stage reactor (10) and the fourth-stage reactor (14).

5. The system for continuous synthesis of glycine according to claim 4, characterized in that: The first stage reactor (1), the second stage reactor (6), the third stage reactor (10) and the fourth stage reactor (14) are respectively provided with a first tail gas outlet pipe (25), a second tail gas outlet pipe (26), a third tail gas outlet pipe (27) and a fourth tail gas outlet pipe (28).

6. The system for continuous synthesis of glycine according to claim 5, characterized in that: The mother liquor outlet pipe (22) is connected to the mother liquor storage tank (29), the mother liquor storage tank (29) is connected to the first mother liquor return pipe (30), the first mother liquor return pipe (30) is equipped with a mother liquor return pump (31), a second mother liquor return pipe (32) and a third mother liquor return pipe (33), and the second mother liquor return pipe (32) is connected to the second discharge pipe (9).

7. The system for continuous synthesis of glycine according to claim 6, characterized in that: The third mother liquor reflux pipe (33) is connected to the hexamethylenetetramine solution inlet pipe (2).

8. The system for continuous synthesis of glycine according to claim 6, characterized in that: The third mother liquor reflux pipe (33) is connected to the hexamethylenetetramine dissolving vessel (34), the hexamethylenetetramine dissolving vessel (34) is connected to the catalyst storage tank (36) through the third connecting pipe (35), the catalyst storage tank (36) is connected through the fourth connecting pipe (37), and the fourth connecting pipe (37) is connected to the hexamethylenetetramine solution inlet pipe (2).

9. The system for continuous synthesis of glycine according to claim 8, characterized in that: The following pipes are equipped with feed valves (38): hexamethylenetetramine solution inlet pipe (2), first chloroacetic acid inlet pipe (3), first ammonia inlet pipe (4), first discharge pipe (5), second chloroacetic acid inlet pipe (7), second ammonia inlet pipe (8), second discharge pipe (9), third chloroacetic acid inlet pipe (11), third ammonia inlet pipe (12), third discharge pipe (13), fourth ammonia inlet pipe (15), fourth discharge pipe (16), first connecting pipe (19), second connecting pipe (21), mother liquor outlet pipe (22), mixed crystal outlet pipe (23), first tail gas outlet pipe (25), second tail gas outlet pipe (26), third tail gas outlet pipe (27), fourth tail gas outlet pipe (28), first mother liquor return pipe (30), second mother liquor return pipe (32), third mother liquor return pipe (33), and fourth connecting pipe (37).

10. A system for continuous synthesis of glycine according to claim 9, characterized in that: Flow meters (39) are installed on the hexamethylenetetramine solution inlet pipe (2), the first chloroacetic acid inlet pipe (3), the first ammonia inlet pipe (4), the second chloroacetic acid inlet pipe (7), the second ammonia inlet pipe (8), the third chloroacetic acid inlet pipe (11), the third ammonia inlet pipe (12), and the fourth ammonia inlet pipe (15).

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