Cleaning system for preparing glycine based on all-water-phase method

Abstract

The utility model discloses a cleaning system for preparing glycine based on an all-water-phase method, and belongs to the technical field of glycine clean production. A cleaning system for preparing glycine based on an all-water-phase method comprises a chlorination reaction kettle, an ammonification reaction kettle, a crystallization kettle, a filter I, a pulping device, a filter II, a drying device, an electrodialysis membrane device, a bipolar membrane device and the like which are sequentially connected. The glycine in the filtered mother liquor generated in the glycine preparation process is effectively recovered and then is mechanically applied with the catalyst urotropine, so that the once-through yield of the glycine is improved, and the consumption of the catalyst urotropine is reduced; the ammonia water is effectively recovered and reutilized, so that the consumption of the raw material ammonia gas is reduced; in addition, the tail gas is subjected to targeted treatment, and the recycled raw materials are reused, so that the utilization rate of the raw materials is increased, and the method is environment-friendly.

Description

Technical Field

[0001] This utility model specifically relates to a clean system for preparing glycine based on the all-aqueous phase method, belonging to the field of clean production technology of glycine. Background Technology

[0002] Glyphosate, chemically known as N-(methyl phosphate)glycine with the chemical formula C3H8NO5P, is an environmentally friendly, broad-spectrum, non-selective herbicide that effectively eliminates 76 of the world's 78 most harmful weeds (primarily annual broadleaf weeds). Currently, the glycine method dominates glyphosate production in China. Glycine, also known as aminoacetic acid, is an important fine chemical product widely used in the pharmaceutical, food, chemical, and pesticide industries. In pharmaceuticals, it is mainly used in amino acid preparations, chlortetracycline buffers, and as an intermediate for imidazole ethyl ester. In the food industry, it is used as a food additive for flavoring, sterilization, preservation, antioxidation, and nutritional fortification. In the pesticide industry, it is mainly used as a raw material for the synthesis of glyphosate and glyphosate-enhancing agents.

[0003] Industrial glycine is mostly produced by the ammonolysis of chloroacetic acid. This process uses chloroacetic acid and liquid ammonia (or ammonia water) as raw materials, with hexamethylenetetramine as a catalyst. The ammonolysis reaction (75–85 °C, atmospheric pressure) yields a mixture containing glycine and ammonium chloride (a byproduct). This mixture is then separated to obtain the glycine product. Currently, the main separation methods are: 1. Alcohol precipitation: A large amount of methanol is added to the mixture of glycine and ammonium chloride. The glycine product is separated based on the difference in solubility of glycine and ammonium chloride in methanol, as shown in CN1340498A. Because the solubility of ammonium chloride in methanol is much lower than its solubility in water, separating glycine and ammonium chloride requires a large amount of methanol. The final product is solid glycine and a methanol solution containing a large amount of ammonium chloride and a small amount of glycine. Furthermore, a large amount of steam is needed to recover the methanol, resulting in high energy consumption. 2. Electrodialysis: Electrodialysis is used to separate glycine and ammonium chloride. While this reduces the amount of methanol used, it increases electricity consumption.

[0004] Although the prior art CN107868015A discloses "a method for preparing a mixed crystal of glycine and ammonium chloride", this production method is only applicable to the preparation of glycine from methanol, and not applicable to the preparation of glycine from an aqueous phase or an alcohol-water phase; and CN109574864A discloses "a new process for the synthesis of glycine", which solves the problems of increased production costs due to the use of an alcohol-water mixture as a solvent, the large energy consumption required for mother liquor distillation, and the low quality of the by-product ammonium chloride in the prior art, a suitable glycine preparation system is still lacking.

[0005] Therefore, there is a need for a low-cost, high-efficiency raw material (catalyst) utilization system that is energy-efficient, environmentally friendly, and clean, and that can be integrated with the glycine synthesis process. Summary of the Invention

[0006] To address the problems of existing technologies, a clean system for preparing glycine based on an all-aqueous phase method is proposed. This system involves a specific arrangement of components such as a chlorination reactor, ammoniation reactor, crystallization reactor, filter I, pulping device, filter II, drying device, electrodialysis membrane device, and bipolar membrane device. This allows for the effective recovery of glycine from the filtrate generated during the glycine preparation process, which is then reused with the catalyst hexamethylenetetramine to improve the single-pass yield of glycine and reduce the consumption of hexamethylenetetramine. Furthermore, ammonia water is effectively recovered and reused, reducing the consumption of raw material ammonia gas. In addition, tail gas is specifically treated, and the recovered raw materials are reused, improving the utilization rate of raw materials and being environmentally friendly.

[0007] To achieve the above technical objectives, the following technical solution is proposed:

[0008] The purpose of this technical solution is to provide: a clean system for preparing glycine based on the all-aqueous phase method, including a chlorination reactor, an ammoniation reactor, a crystallization reactor, a filter I, a pulping device, a filter II, a drying device, an electrodialysis membrane device, a bipolar membrane device, a chlorination tail gas treatment device, and an ammoniation tail gas treatment device;

[0009] Chlorination reactor: It is connected to acetic acid inlet pipe, chlorine inlet pipe and acetic anhydride inlet pipe; the tail gas outlet of the chlorination reactor is connected to the chlorination tail gas treatment device through tail gas outlet pipe I.

[0010] The chloroacetic acid outlet on the chlorination reactor is connected to the feed inlet on the ammoniation reactor via a chloroacetic acid delivery pipe.

[0011] Ammoniation reactor: It is connected to an ammonia inlet pipe, a catalyst inlet pipe and a water inlet pipe I. The tail gas outlet of the ammoniation reactor is connected to the ammoniation tail gas treatment device through a tail gas outlet pipe II.

[0012] The outlet of the ammoniation liquid on the ammoniation reactor is connected to the feed inlet on the crystallization reactor via an ammoniation liquid delivery pipe.

[0013] Crystallization kettle: It is connected to water inlet pipe II, and the mixed crystal outlet on the crystallization kettle is connected to the feed inlet of filter I;

[0014] Filter I: The wet material outlet of Filter I is connected to the feed inlet of the pulping device, and the mother liquor outlet of Filter I is connected to the electrodialysis membrane device through the mother liquor recovery pipe;

[0015] Pulping device: connected to water inlet pipe III, the mixing outlet of the pulping device is connected to the feed inlet of filter II;

[0016] Filter II: The crude glycine outlet of Filter II is connected to the feed inlet of the drying unit, and the drying unit is connected to the finished glycine tank; the mother liquor outlet of Filter II is connected to the electrodialysis membrane device through the mother liquor recovery pipe.

[0017] The desalination outlet of the electrodialysis membrane unit is connected to the chlorination reactor through the electrodialysis desalination reuse pipe, and the desalination outlet of the electrodialysis membrane unit is also connected to the water inlet pipe III through the electrodialysis desalination reuse pipe.

[0018] The concentrate outlet of the electrodialysis membrane unit is connected to a multi-effect concentrator via concentrate outlet pipe I. The solid outlet of the multi-effect concentrator is connected to ammonium chloride outlet pipe I, and the liquid outlet of the multi-effect concentrator is connected to a decomposition reactor. The decomposition reactor is connected to a calcium oxide inlet pipe and a water inlet pipe IV. The solid outlet of the decomposition reactor is connected to ammonium chloride outlet pipe II, and the gas outlet of the decomposition reactor is connected to a water absorption tower. The water absorption tower is connected to a water inlet pipe V, and the liquid outlet of the water absorption tower is connected to an ammonia storage tank via an ammonia recovery pipe, or the liquid outlet of the water absorption tower is connected to an ammoniation reactor via an ammonia recovery pipe.

[0019] The concentrated solution outlet of the electrodialysis membrane device is also connected to the bipolar membrane device through concentrated solution outlet pipe II. The dilute ammonia water outlet of the bipolar membrane device is connected to the water inlet pipe V through the dilute ammonia water reuse pipe. The dilute hydrochloric acid outlet of the bipolar membrane device is connected to the chlorination tail gas treatment device through the dilute hydrochloric acid reuse pipe.

[0020] Furthermore, a chlorination top vessel is provided between the acetic anhydride inlet pipe and the chlorination reactor, and the chlorination top vessel is connected to the chlorination reactor through an acetic anhydride overflow pipe; the tail gas outlet on the chlorination top vessel is connected to the tail gas outlet pipe I through tail gas branch pipe I.

[0021] The tail gas outlet on the chlorination reactor is also connected to the condenser. The condenser is connected to the chlorination reactor through the acetic anhydride reflux pipe. The tail gas outlet on the condenser is connected to the tail gas outlet pipe I through tail gas branch pipe II.

[0022] Furthermore, the chlorinated tail gas treatment device includes an acetic acid absorption tower, a hydrochloric acid falling film absorption tower, an empty tower and an alkaline scrubbing tower connected in sequence. The tail gas outlet pipe I is connected to the inlet of the acetic acid absorption tower, and the acetic acid outlet of the acetic acid absorption tower is connected to the acetic acid storage tank through an acetic acid recovery pipe.

[0023] The hydrochloric acid outlet of the hydrochloric acid falling film absorption tower is connected to the hydrochloric acid storage tank via a hydrochloric acid recovery pipe.

[0024] The outlet of the alkali washing tower is connected to the incinerator.

[0025] More preferably, there are at least two acetic acid absorption towers, which are connected in series. The acetic acid outlet of the acetic acid absorption tower at the first station is connected to the acetic acid storage tank through an acetic acid recovery pipe.

[0026] There are at least two hydrochloric acid falling film absorption towers, which are connected in series. The hydrochloric acid liquid outlet of the hydrochloric acid falling film absorption tower at the first station is connected to the hydrochloric acid storage tank through a hydrochloric acid recovery pipe, and the hydrochloric acid liquid outlet of the hydrochloric acid falling film absorption tower at the next station is connected to the adjacent hydrochloric acid falling film absorption tower at the previous station through a hydrochloric acid reflux pipe. The hydrochloric acid falling film absorption tower at the last station is connected to a washing liquid inlet pipe.

[0027] There are at least two empty towers, which are connected in series.

[0028] There are at least two alkaline washing towers, which are connected in series. The outlet of the last alkaline washing tower is connected to the incinerator.

[0029] Furthermore, both filter I and filter II are vacuum belt filters.

[0030] Furthermore, the multi-effect concentrator includes a first-effect concentrator, a second-effect concentrator, and a third-effect concentrator connected in sequence. The first-effect concentrator, the second-effect concentrator, and the third-effect concentrator are arranged in series, and the ammonium chloride outlet of the third-effect concentrator is connected to an ammonium chloride outlet pipe I.

[0031] Furthermore, the single-effect concentrator is connected to a steam inlet pipe, the triple-effect concentrator is connected to a condensate outlet pipe, the condensate outlet pipe is connected to a washing liquid inlet pipe, and the condensate outlet pipe is also connected to a water inlet pipe V.

[0032] Furthermore, there are at least two water absorption towers, which are connected in series. The liquid outlet of the water absorption tower at the first station is connected to the ammonia storage tank through an ammonia recovery pipe, or the liquid outlet of the water absorption tower is connected to the ammoniation reactor through an ammonia recovery pipe.

[0033] The water absorption tower at the final workstation is connected to water inlet pipe V.

[0034] The terms "above," "between," "first workstation," "next workstation," and "last workstation" used in this technical solution are defined based on the actual usage conditions and are common terms used in this technical field, as well as common terms used by those skilled in the art in actual use.

[0035] In the description of this technical solution, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "equipped with," and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this technical solution based on the specific circumstances.

[0036] The beneficial technical effects of adopting this technical solution are as follows:

[0037] This invention utilizes a specific arrangement of components such as a chlorination reactor, an ammoniation reactor, a crystallization reactor, filter I, a pulping device, filter II, a drying device, an electrodialysis membrane device, and a bipolar membrane device to effectively recover glycine from the filtrate mother liquor generated during the glycine preparation process. This recovery is then combined with the catalyst hexamethylenetetramine, increasing the single-pass yield of glycine and reducing the consumption of hexamethylenetetramine. Furthermore, it effectively recovers and reuses ammonia water, reducing the consumption of raw material ammonia. In addition, targeted treatment of the tail gas allows for the reuse of the recovered raw materials, not only improving the utilization rate of raw materials but also being environmentally friendly. Attached Figure Description

[0038] Figure 1 This is a structural block diagram of the present utility model;

[0039] In the diagram: 1. Chlorination reactor; 2. Ammoniation reactor; 3. Crystallization reactor; 4. Filter I; 5. Pulping device; 6. Filter II; 7. Drying device; 8. Electrodialysis membrane device; 9. Bipolar membrane device; 10. Chlorination tail gas treatment device; 11. Ammoniation tail gas treatment device; 12. Acetic acid inlet pipe; 13. Chlorine inlet pipe; 14. Acetic anhydride inlet pipe; 15. Tail gas outlet pipe I; 16. Chloroacetic acid conveying pipe; 17. Ammonia inlet pipe; 18. Catalyst inlet pipe; 19. Water inlet pipe I; 20. Tail gas outlet pipe II; 21. Ammoniation liquid conveying pipe; 22. Ammonia water recovery pipe; 23. Water inlet pipe II; 26. Mother liquor recovery pipe; 27. Water inlet pipe III; 30. Glycine finished product tank; 31. Electrodialysis dilute solution reuse pipe; 32. Concentrated solution outlet pipe. Ⅰ, 33, Multi-effect concentrator, 34, Ammonium chloride outlet pipe Ⅰ, 35, Decomposition reactor, 36, Calcium oxide inlet pipe, 37, Water inlet pipe Ⅳ, 38, Ammonium chloride outlet pipe Ⅱ, 39, Water absorption tower, 40, Water inlet pipe Ⅴ, 41, Ammonia storage tank, 42, Concentrated liquid outlet pipe Ⅱ, 43, Dilute ammonia water reuse pipe, 44, Dilute hydrochloric acid reuse pipe, 45, Chlorination top vessel, 46, Acetic anhydride overflow pipe, 47, Tail gas branch pipe Ⅰ, 48, Condenser, 49, Acetic anhydride reflux pipe, 50, Tail gas branch pipe Ⅱ, 51, Acetic acid absorption tower, 52, Hydrochloric acid falling film absorption tower, 53, Empty tower, 54, Alkali washing tower, 55, Acetic acid recovery pipe, 56, Hydrochloric acid recovery pipe, 57, Hydrochloric acid reflux pipe, 58, Washing liquid inlet pipe, 59, Steam inlet pipe, 60, Condensate outlet pipe. Detailed Implementation

[0040] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0041] The ammonolysis of chloroacetic acid is the primary method used in glycine synthesis. This method uses hexamethylenetetramine as a catalyst and liquid ammonia (or ammonia water) and chloroacetic acid as the main raw materials. The ammonolysis reaction yields a glycated liquid, which is then separated by alcohol precipitation to obtain glycine, with ammonium chloride as a byproduct. Currently, the ammonolysis process mainly includes ammonolysis, alcohol precipitation crystallization, solvent recovery, and drying. The ammonolysis reaction temperature is 75–85 °C, and the reaction pressure is atmospheric pressure.

[0042] The advantages of ammonolysis of chloroacetic acid include readily available raw materials, a simple process, convenient operation, and low equipment investment. However, due to the relatively small difference in solubility between glycine and ammonium chloride in methanol, the main product glycine and the byproduct ammonium chloride are difficult to separate, resulting in low catalyst utilization and inconvenient treatment of the byproduct ammonium chloride. These factors lead to high purification costs and low glycine yield. Therefore, a system for preparing glycine based on an all-aqueous phase method is proposed.

[0043] The following examples illustrate this.

[0044] Example 1

[0045] This embodiment provides a clean system for preparing glycine based on an all-aqueous phase method, such as... Figure 1As shown, the system includes a chlorination reactor 1, an ammoniation reactor 2, a crystallization reactor 3, a filter I 4, a pulping device 5, a filter II 6, a drying device 7, an electrodialysis membrane device 8, and a bipolar membrane device 9. The chloroacetic acid outlet of the chlorination reactor 1 is connected to the feed inlet of the ammoniation reactor 2 via a chloroacetic acid delivery pipe 16. The ammoniation reactor 2 is connected to a water inlet pipe I 19, and the ammoniation liquid outlet of the ammoniation reactor 2 is connected to the feed inlet of the crystallization reactor 3 via an ammoniation liquid delivery pipe 21. The crystallization reactor 3 is connected to a water inlet pipe II 23, and the mixed crystal outlet of the crystallization reactor 3 is connected to the feed inlet of the filter I 4. The wet material outlet of filter I4 is connected to the inlet of pulping device 5. The mother liquor outlet of filter I4 is connected to electrodialysis membrane device 8 via mother liquor recovery pipe 26. Pulping device 5 is connected to water inlet pipe III 27, and the mixed crystal outlet of pulping device 5 is connected to the inlet of filter II 6. The crude glycine outlet of filter II 6 is connected to the inlet of drying device 7, and drying device 7 is connected to glycine finished product tank 30. The mother liquor outlet of filter II 6 is connected to electrodialysis membrane device 8 via mother liquor recovery pipe 26. The dilute liquid outlet of electrodialysis membrane device 8 is connected to electrodialysis dilute liquid reuse pipe 31. Connected to the chlorination reactor 1, the dilute outlet of the electrodialysis membrane device 8 is also connected to the water inlet pipe III 27 via the electrodialysis dilute reuse pipe 31; the concentrate outlet of the electrodialysis membrane device 8 is connected to the multi-effect concentrator 33 via the concentrate outlet pipe I 32, the solid outlet of the multi-effect concentrator 33 is connected to the ammonium chloride outlet pipe I 34, and the liquid outlet of the multi-effect concentrator 33 is connected to the decomposition reactor 35; the decomposition reactor 35 is connected to the calcium oxide inlet pipe 36 and the water inlet pipe IV 37, the solid outlet of the decomposition reactor 35 is connected to the ammonium chloride outlet pipe II 38, and the gas outlet of the decomposition reactor 35 is connected to... There is a water absorption tower 39; the water absorption tower 39 is connected to a water inlet pipe V40, and the liquid outlet of the water absorption tower 39 is connected to the ammonia storage tank 41 through the ammonia recovery pipe 22, or the liquid outlet of the water absorption tower 39 is connected to the ammoniation reactor 2 through the ammonia recovery pipe 22; the concentrated liquid outlet of the electrodialysis membrane device 8 is also connected to the bipolar membrane device 9 through the concentrated liquid outlet pipe II42, the dilute ammonia outlet of the bipolar membrane device 9 is connected to the water inlet pipe V40 through the dilute ammonia reuse pipe 43, and the dilute hydrochloric acid outlet of the bipolar membrane device 9 is connected to the chlorination tail gas treatment device 10 through the dilute hydrochloric acid reuse pipe 44.

[0046] For both filter I4 and filter II6, vacuum belt filters are preferred.

[0047] In the production of glycine, this preparation system effectively recovers glycine from the filtrate produced during the glycine preparation process and reuses it with the catalyst hexamethylenetetramine to improve the single-pass yield of glycine and reduce the consumption of the catalyst hexamethylenetetramine; at the same time, it realizes the comprehensive utilization of ammonium chloride-containing wastewater, etc.

[0048] Among them, the crystallization kettle 3 is connected to a water inlet pipe II23, that is, the glycine crystallization process adopts the aqueous phase method, using a saturated glycine aqueous solution to replace organic separation and dissolution, thereby reducing safety risks;

[0049] Electrodialysis membrane device 8 is used to separate glycine and ammonium chloride from the crystallization mother liquor. The glycine-containing mother liquor is reused in the ammoniation process, and the ammonium chloride-containing concentrated water enters the bipolar membrane device 9. The ammonium chloride concentrated water produced by the electrodialysis membrane device 8 enters the bipolar membrane to separate dilute ammonia and dilute hydrochloric acid. The dilute ammonia is returned to the ammoniation process for water replenishment, and the dilute hydrochloric acid is returned to the chlorination process for water replenishment through hydrochloric acid falling membrane absorption.

[0050] Example 2

[0051] Based on Example 1, this example further defines the chlorination reactor 1 and the ammoniation reactor 2 to further illustrate the technical solution.

[0052] Chlorination reactor 1: It is connected to acetic acid inlet pipe 12, chlorine inlet pipe 13 and acetic anhydride inlet pipe 14. The tail gas outlet of chlorination reactor 1 is connected to chlorination tail gas treatment device 10 through tail gas outlet pipe I 15. A chlorination top vessel 45 is provided between acetic anhydride inlet pipe 14 and chlorination reactor 1. The chlorination top vessel 45 is connected to chlorination reactor 1 through acetic anhydride overflow pipe 46. The tail gas outlet of chlorination top vessel 45 is connected to tail gas outlet pipe I 15 through tail gas branch pipe I 47. The tail gas outlet of chlorination top vessel 45 is also connected to condenser 48. Condenser 48 is connected to chlorination reactor 1 through acetic anhydride reflux pipe 49. The tail gas outlet of condenser 48 is connected to tail gas outlet pipe I 15 through tail gas branch pipe II 50.

[0053] The ammoniation reactor 2 is also connected to an ammonia inlet pipe 17 and a catalyst inlet pipe 18. The tail gas outlet of the ammoniation reactor 2 is connected to an ammoniation tail gas treatment device 11 through a tail gas outlet pipe II 20.

[0054] Example 3

[0055] Based on Embodiments 1-2, this embodiment further defines the chlorination tail gas treatment device 10 to further illustrate the technical solution.

[0056] The chlorination tail gas treatment device 10 includes an acetic acid absorption tower 51, a hydrochloric acid falling film absorption tower 52, an empty tower 53, and an alkaline scrubbing tower 54 connected in sequence. The tail gas outlet pipe I15 is connected to the inlet of the acetic acid absorption tower 51, and the acetic acid outlet of the acetic acid absorption tower 51 is connected to the acetic acid storage tank through the acetic acid recovery pipe 55. The hydrochloric acid outlet of the hydrochloric acid falling film absorption tower 52 is connected to the hydrochloric acid storage tank through the hydrochloric acid recovery pipe 56. The outlet of the alkaline scrubbing tower 54 is connected to the incinerator.

[0057] There are at least two acetic acid absorption towers 51, which are connected in series. The acetic acid outlet of the acetic acid absorption tower 51 located at the first station is connected to the acetic acid storage tank through the acetic acid recovery pipe 55.

[0058] Among them, there are at least two hydrochloric acid falling film absorption towers 52, which are arranged in series. The hydrochloric acid liquid outlet of the hydrochloric acid falling film absorption tower 52 located at the first station is connected to the hydrochloric acid storage tank through the hydrochloric acid recovery pipe 56, and the hydrochloric acid liquid outlet of the hydrochloric acid falling film absorption tower 52 located at the next station is connected to the adjacent hydrochloric acid falling film absorption tower 52 located at the previous station through the hydrochloric acid return pipe 57. The hydrochloric acid falling film absorption tower 52 located at the last station is connected to the washing liquid inlet pipe 58.

[0059] Among them, there are at least two empty towers 53, and the empty towers 53 are arranged in series;

[0060] There are at least two alkaline washing towers 54, which are connected in series, and the outlet of the last alkaline washing tower 54 is connected to the incinerator.

[0061] Example 4

[0062] Based on embodiments 1-3, this embodiment further defines the multi-effect concentrator 33 to further illustrate the technical solution.

[0063] The multi-effect concentrator 33 includes a first-effect concentrator, a second-effect concentrator, and a third-effect concentrator connected in sequence. The first-effect concentrator, the second-effect concentrator, and the third-effect concentrator are arranged in series. An ammonium chloride outlet pipe I34 is connected to the ammonium chloride outlet of the third-effect concentrator.

[0064] The first-effect concentrator is connected to a steam inlet pipe 59, the third-effect concentrator is connected to a condensate outlet pipe 60, the condensate outlet pipe 60 is connected to a washing liquid inlet pipe 58, and the condensate outlet pipe 60 is also connected to a water inlet pipe V40.

[0065] Example 5

[0066] Based on embodiments 1-4, this embodiment further defines the water absorption tower 39 to further illustrate the technical solution.

[0067] There are at least two water absorption towers 39, which are connected in series. The liquid outlet of the first water absorption tower 39 is connected to the ammonia storage tank 41 through the ammonia recovery pipe 22, or the liquid outlet of the water absorption tower 39 is connected to the ammoniation reactor 2 through the ammonia recovery pipe 22. The last water absorption tower 39 is connected to the water inlet pipe V40.

Claims

1. A clean system for the preparation of glycine based on an all-aqueous phase process, characterized by, The chlorination reactor (1), the ammoniation reactor (2), the crystallization kettle (3), the filter I (4), the beating device (5), the filter II (6), the drying device (7), the electrodialysis membrane device (8) and the bipolar membrane device (9) are connected. The chlorination reactor (1) is connected with the acetic acid inlet pipe (12), the chlorine inlet pipe (13) and the acetic anhydride inlet pipe (14); the ammoniation reactor (2) is further connected with the ammonia inlet pipe (17) and the catalyst inlet pipe (18). The crystallization kettle (3) is connected with the water inlet pipe II (23); the mixed crystal outlet of the crystallization kettle (3) is connected with the feed inlet of the filter I (4). The filter I (4) is connected with the wet material outlet connected with the feed inlet of the beating device (5); the filter mother liquor outlet of the filter I (4) is connected with the electrodialysis membrane device (8) through the mother liquor recovery pipe (26). The beating device (5) is connected with the water inlet pipe III (27); the mixed crystal outlet of the beating device (5) is connected with the feed inlet of the filter II (6). The filter II (6) is connected with the glycine crude product outlet connected with the feed inlet of the drying device (7); the drying device (7) is connected with the glycine product tank (30); the filter mother liquor outlet of the filter II (6) is connected with the electrodialysis membrane device (8) through the mother liquor recovery pipe (26). The dilute liquid outlet of the electrodialysis membrane device (8) is connected with the chlorination reactor (1) through the electrodialysis dilute liquid recycling pipe (31); the dilute liquid outlet of the electrodialysis membrane device (8) is further connected with the water inlet pipe III (27) through the electrodialysis dilute liquid recycling pipe (31). The concentrated liquid outlet of the electrodialysis membrane device (8) is connected with the multi-effect concentrator (33) through the concentrated liquid outlet pipe I (32); the solid outlet of the multi-effect concentrator (33) is connected with the ammonium chloride outlet pipe I (34); the liquid outlet of the multi-effect concentrator (33) is connected with the decomposition reactor (35); the decomposition reactor (35) is connected with the calcium oxide inlet pipe (36) and the water inlet pipe IV (37); the solid outlet of the decomposition reactor (35) is connected with the ammonium chloride outlet pipe II (38); the gas outlet of the decomposition reactor (35) is connected with the water absorption tower (39); the water absorption tower (39) is connected with the water inlet pipe V (40); the liquid outlet of the water absorption tower (39) is connected with the ammonia water storage tank (41) through the ammonia water recovery pipe (22), or the liquid outlet of the water absorption tower (39) is connected with the ammoniation reactor (2) through the ammonia water recovery pipe (22). The concentrated liquid outlet of the electrodialysis membrane device (8) is further connected with the bipolar membrane device (9) through the concentrated liquid outlet pipe II (42); the dilute ammonia water outlet of the bipolar membrane device (9) is connected with the water inlet pipe V (40) through the dilute ammonia water recycling pipe (43); the dilute hydrochloric acid outlet of the bipolar membrane device (9) is connected with the chlorination tail gas treatment device (10) through the dilute hydrochloric acid recycling pipe (44).

2. The clean system for preparing glycine based on the all-aqueous phase method according to claim 1, characterized by, The chlorination reactor (1) is connected with the acetic acid inlet pipe (12), the chlorine inlet pipe (13) and the acetic anhydride inlet pipe (14); the ammoniation reactor (2) is further connected with the ammonia inlet pipe (17) and the catalyst inlet pipe (18).

3. The clean system for preparing glycine based on the all-aqueous phase method according to claim 2, characterized by, The chlorination reactor (1) is connected with a chlorination tail gas treatment device (10) through a tail gas outlet pipe I (15) connected with the tail gas outlet of the chlorination reactor (1), and the ammoniation reactor (2) is connected with an ammoniation tail gas treatment device (11) through a tail gas outlet pipe II (20) connected with the tail gas outlet of the ammoniation reactor (2).

4. The clean system for preparing glycine based on the all-aqueous phase method according to claim 3, characterized by, The chlorination top kettle (45) is connected with the chlorination reactor (1) through an acetic anhydride overflow pipe (46), and the tail gas outlet of the chlorination top kettle (45) is connected with the tail gas outlet pipe I (15) through a tail gas branch pipe I (47). The tail gas outlet of the chlorination top kettle (45) is also connected with a condenser (48), the condenser (48) is connected with the chlorination reactor (1) through an acetic anhydride reflux pipe (49), and the tail gas outlet of the condenser (48) is connected with the tail gas outlet pipe I (15) through a tail gas branch pipe II (50).

5. The clean system for preparing glycine based on the all-aqueous phase method according to claim 4, characterized by, The chlorination tail gas treatment device (10) comprises acetic acid absorption towers (51), a hydrochloric acid falling film absorption tower (52), an empty tower (53) and an alkali washing tower (54) connected in sequence, the tail gas outlet pipe I (15) is connected with the inlet of the acetic acid absorption tower (51), the acetic acid outlet of the acetic acid absorption tower (51) is connected with an acetic acid storage tank through an acetic acid recovery pipe (55); the hydrochloric acid outlet of the hydrochloric acid falling film absorption tower (52) is connected with a hydrochloric acid storage tank through a hydrochloric acid recovery pipe (56); the outlet of the alkali washing tower (54) is connected with a incinerator.

6. The clean system for preparing glycine based on the all-aqueous phase method according to claim 5, characterized by, The acetic acid absorption towers (51) are at least two, and are arranged in series between the acetic acid absorption towers (51), the acetic acid outlet of the acetic acid absorption tower (51) arranged at the first station is connected with an acetic acid storage tank through an acetic acid recovery pipe (55); the hydrochloric acid falling film absorption towers (52) are at least two, and are arranged in series between the hydrochloric acid falling film absorption towers (52), the hydrochloric acid outlet of the hydrochloric acid falling film absorption tower (52) arranged at the first station is connected with a hydrochloric acid storage tank through a hydrochloric acid recovery pipe (56), the hydrochloric acid outlet of the hydrochloric acid falling film absorption tower (52) arranged at the last station is connected with the hydrochloric acid falling film absorption tower (52) arranged at the adjacent previous station through a hydrochloric acid reflux pipe (57), and the hydrochloric acid falling film absorption tower (52) arranged at the last station is connected with a washing liquid inlet pipe (58); the empty towers (53) are at least two, and are arranged in series between the empty towers (53); the alkali washing towers (54) are at least two, and are arranged in series between the alkali washing towers (54), and the outlet of the alkali washing tower (54) arranged at the last station is connected with a incinerator.

7. The clean system for preparing glycine based on the all-aqueous phase method according to claim 1, characterized by, The filter I (4) and the filter II (6) are vacuum belt filters.

8. The clean system for preparing glycine based on the all-aqueous phase method according to claim 1, characterized by, The multi-effect concentrator (33) comprises a one-effect concentrator, a two-effect concentrator and a three-effect concentrator connected in sequence, the one-effect concentrator, the two-effect concentrator and the three-effect concentrator are arranged in series, and the ammonium chloride outlet of the three-effect concentrator is connected with an ammonium chloride outlet pipe I (34).

9. The clean system for preparing glycine based on the all-aqueous phase method according to claim 8, characterized by, The one-effect concentrator is connected with a steam inlet pipe (59), the three-effect concentrator is connected with a condensed water outlet pipe (60), the condensed water outlet pipe (60) is connected with the washing liquid inlet pipe (58), and the condensed water outlet pipe (60) is also connected with the water inlet pipe V (40).

10. The clean system for preparing glycine based on the all-aqueous phase method according to claim 9, characterized by, The water absorption tower (39) is at least two, and the water absorption towers (39) are arranged in series, the liquid outlet of the water absorption tower (39) of the first station is connected with the ammonia water storage tank (41) through the ammonia water recovery pipe (22), or the liquid outlet of the water absorption tower (39) is connected with the ammoniation reaction kettle (2) through the ammonia water recovery pipe (22); the water absorption tower (39) of the last station is connected with the water inlet pipe V (40).

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