Glycine crystallization regulation and control device

Abstract

The utility model provides a glycine crystallization regulation and control device, which relates to the technical field of glycine preparation and comprises a raw material tank filled with ammonification reaction liquid; the alcohol precipitation crystallization kettle is connected with the raw material tank; the first feeding pipe and the second feeding pipe are both connected with the alcohol precipitation crystallization kettle, and a pipeline flowmeter is arranged in the first feeding pipe; the radar liquid level meter is arranged on the alcohol precipitation crystallization kettle; the pH meter is used for monitoring the pH value of the material in the alcohol precipitation crystallization kettle; the pipeline flow meter, the radar liquid level meter and the pH meter are connected with the control system in a wired or wireless mode; wherein the first feeding pipe is used for adding methanol into the alcohol precipitation crystallization kettle, and the second feeding pipe is used for adding hydrochloric acid into the alcohol precipitation crystallization kettle. The glycine crystallization regulation and control device provided by the utility model can regulate and control the pH value to be close to a glycine isoelectric point in an alcohol precipitation process, and can track the adding amount of methanol in real time.

Description

Technical Field

[0001] This invention belongs to the field of glycine preparation technology, specifically relating to a glycine crystallization control device. Background Technology

[0002] Glycine, also known as aminoacetic acid, is the simplest structural amino acid among natural α-amino acids. It is used in the fields of glyphosate pesticide, feed additives, food additives, and nutritional products. Domestic enterprises generally use the traditional chloroacetic acid ammonolysis method, which uses hexamethylenetetramine as a catalyst. After the chloroacetic acid solution and ammonia gas react to the endpoint, under alcohol precipitation conditions, glycine and the byproduct ammonium chloride in a methanol-water solution are produced. The wet glycine product is then separated by centrifugation and dried by airflow to obtain the final product. The mother liquor from centrifugation is distilled to recover methanol, and the residue is evaporated, concentrated, cooled, crystallized, centrifuged, and packaged to obtain the finished ammonium chloride product.

[0003] The main defects of existing technologies are:

[0004] (1) The alcohol precipitation process uses distillation to recover methanol. Because the mother liquor decomposes hexamethylenetetramine and glycine to produce low-boiling-point components such as ammonia and formaldehyde, which dissolve in methanol, and methanol is slightly alkaline, the pH slowly rises during the alcohol precipitation process, deviating from the isoelectric point of glycine, resulting in poor yield and particle size.

[0005] (2) During the production process, the methanol dripping pipeline is relatively thick. During the liquid-on-pipe flow process, the impact of the ammonia liquid can easily generate a large number of fine seed crystals, reducing the particle size of the product. Furthermore, it is impossible to track the amount of methanol added and the reaction progress in real time.

[0006] Therefore, it is particularly important to develop a device that can effectively regulate the number of seed crystals and particle size during the glycine crystallization process, improve the glycine yield, and reduce secondary crystallization losses. Utility Model Content

[0007] This invention addresses the problems existing in the prior art by providing a glycine crystallization control device. By adding hydrochloric acid, the pH of the material is controlled to be close to 6.0, which can adjust the pH of the reaction solution to the isoelectric point of glycine. Furthermore, the device can track the amount of methanol added and the reaction progress in real time using a radar level gauge.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0009] A glycine crystallization control device includes a raw material tank containing an amination reaction solution; and

[0010] An alcohol precipitation crystallization vessel, wherein the alcohol precipitation crystallization vessel is connected to the raw material tank; and

[0011] A first feed pipe and a second feed pipe, both connected to the alcohol precipitation crystallization vessel, are provided with a flow meter inside the first feed pipe; and

[0012] A radar level gauge is installed on the alcohol precipitation crystallization vessel; and

[0013] A pH meter, used to monitor the pH value of the material inside the alcohol precipitation crystallization vessel; and

[0014] The control system, wherein the pipeline flow meter, the radar level gauge, the pH meter and the control system are connected via wired or wireless means;

[0015] The first feed pipe is used to add methanol to the alcohol precipitation crystallization vessel, and the second feed pipe is used to add hydrochloric acid to the alcohol precipitation crystallization vessel.

[0016] Furthermore, it also includes a first filter and a second filter, wherein the first end of the first filter is connected to the raw material tank and the second end is connected to the second filter, and the second end of the second filter is connected to the alcohol precipitation crystallization kettle.

[0017] Furthermore, both the first filter and the second filter are provided with a first jacket.

[0018] Furthermore, it also includes a first inlet pipe and a first outlet pipe. The first inlet pipe is disposed between the second filter and the alcohol precipitation crystallization vessel, and the first outlet pipe is disposed between the raw material tank and the first filter. The first feed pipe has a double-layer structure, and the second feed pipe has a ring structure.

[0019] Furthermore, it also includes a temperature field display instrument, which is installed on the alcohol precipitation crystallization vessel and is connected to the control system via wired or wireless means.

[0020] Furthermore, a second jacket is provided outside the alcohol precipitation crystallization vessel. Cooling liquid enters the second jacket from the lower right opening to cool the material inside the alcohol precipitation crystallization vessel and flows out from the upper left opening.

[0021] Furthermore, the alcohol precipitation crystallization vessel is equipped with a spiral inner coil, and the second jacket is connected to the spiral inner coil. The cooling liquid enters from the second jacket and exits from the spiral inner coil.

[0022] Furthermore, the cooling liquid is circulating water or 7°C brine. When a first cooling rate is required, the control system controls the input of 7°C brine. When a second cooling rate is required, the control system controls the input of circulating water. The first cooling rate is greater than the second cooling rate.

[0023] Furthermore, it also includes a motor and a stirring paddle. The motor is connected to the control system via a wired or wireless means, and the output shaft of the motor is rotatably connected to the stirring paddle, which is disposed inside the alcohol precipitation crystallization vessel.

[0024] Furthermore, it also includes a centrifuge connected to the outlet of the alcohol precipitation crystallization vessel.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) This utility model provides a double-layer methanol dripping pipeline and a ring hydrochloric acid addition pipeline to avoid impacting the ammonia liquid during the liquid-on-line flow process, which would lead to the generation of a large number of fine seed crystals and reduce the particle size of the product. It also combines a radar level gauge to track the amount of methanol added and the reaction progress in real time. The hydrochloric acid reacts with the ammonia dissolved in the weakly alkaline methanol to generate ammonium chloride, without introducing other impurity ions, and at the same time, it increases the yield of the by-product ammonium chloride to a certain extent.

[0027] (2) The two-stage filtration system provided by this utility model effectively removes raw and auxiliary materials, mechanical impurities, colored impurities, macromolecular polymers and cooling crystallization particles during the reaction process by adding a bag-type activated carbon filter and a precision filter. A first water inlet pipe is added after the precision filter for back flushing, which avoids the problems of insufficient filtration and difficulty in cleaning after clogging of traditional simple filters. After the first back flushing, the water is temporarily stored in the raw material tank and can be used directly as makeup water for the reaction, thereby achieving the purpose of improving efficiency, reducing waste discharge and environmentally friendly production.

[0028] (3) The dual refrigerant switching temperature control system provided by this utility model can achieve precise control of cooling capacity by using circulating water and 7℃ brine in the plant area. This avoids the limitations of relying on the temperature of circulating water and the long cooling time during the alcohol precipitation cooling crystallization process. It also avoids the problem of particle size being too small and glycine yield being reduced due to mismatched cooling rates. This can improve the cooling rate and increase the operational flexibility of centrifugal discharge temperature, as well as improve the yield of finished products. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the glycine crystallization control device provided in the embodiments of this utility model.

[0030] In the diagram, 1. Raw material tank; 2. Alcohol precipitation crystallization vessel; 3. First feed pipe; 4. Second feed pipe; 5. Radar level gauge; 6. pH meter; 7. First filter; 8. Second filter; 9. First jacket; 10. First water inlet pipe; 11. First water outlet pipe; 12. Temperature display instrument; 13. Second jacket; 14. Spiral inner coil; 15. Motor; 16. Agitator; 17. Centrifuge. Detailed Implementation

[0031] To address the issues of decreased glycine yield and particle size, this invention provides a glycine crystallization control device, comprising a raw material tank 1 containing an amination reaction solution; an alcohol precipitation crystallization vessel 2 connected to the raw material tank 1; and a first feed pipe 3 and a second feed pipe 4, both connected to the alcohol precipitation crystallization vessel 2. The first feed pipe 3 is used to add methanol to the alcohol precipitation crystallization vessel 2. A flow meter can be installed in the first feed pipe 3, connected to a control system, to control the methanol flow rate. The first feed pipe 3 can be a double-layered methanol drip line with spray nozzles, enabling uniform methanol spraying.

[0032] The second feed pipe 4 is used to add hydrochloric acid into the alcohol precipitation crystallization vessel 2. The second feed pipe 4 can be a hydrochloric acid ring distributor. By adding hydrochloric acid, the pH value during the alcohol precipitation process can be uniformly controlled. The system also includes a radar level gauge 5, which is installed on the alcohol precipitation crystallization vessel 2 to track the amount of methanol added and the reaction progress in real time; and a pH meter 6, which is used to monitor the pH value of the material in the alcohol precipitation crystallization vessel 2. The control system can be a DCS (Distributed Control System). The pipeline flow meter, the radar level gauge 5, and the pH meter 6 are connected to the control system via wired or wireless means.

[0033] The glycine crystallization control device provided by this utility model can control the pH value to be close to the isoelectric point of glycine during the alcohol precipitation process by adding a second feed pipe 4 to add hydrochloric acid. It can also control the methanol dropping rate in real time through a methanol dropping pipeline with a pipeline flow meter, and can track the amount of methanol added and the reaction progress by setting a radar level gauge 5. Thus, it can effectively adjust the particle size during the glycine crystallization process and improve the glycine yield.

[0034] In the glycine production process, impurities can be introduced during the storage and transportation of raw materials and auxiliary materials, affecting the crystal form and particle size of glycine. To remove these impurities, a first filter 7 and a second filter 8 are included. The first end of the first filter 7 is connected to the raw material tank 1, and the second end is connected to the second filter 8. The second end of the second filter 8 is connected to the alcohol precipitation crystallization kettle 2. The first filter 7 can be a bag-type activated carbon filter, and the second filter 8 can be a precision filter. Through two-stage filtration, mechanical impurities, colored impurities, large polymer molecules, and small particles from cooling crystals can be removed from the raw materials and auxiliary materials, as well as from the reaction process.

[0035] In order to keep the ammonia reaction solution warm, both the first filter 7 and the second filter 8 are provided with a first jacket 9, which allows steam to be introduced into the first jacket 9 to keep the ammonia reaction solution warm and prevent crystals from precipitating in the first filter 7 and the second filter 8 and clogging the filters.

[0036] When the first filter 7 and / or the second filter 8 become clogged, a first inlet pipe 10 and a first outlet pipe 11 are also included to unclog them. The first inlet pipe 10 is located between the second filter 8 and the alcohol precipitation crystallization vessel 2. Water is introduced into the first inlet pipe 10 to backflow the first filter 7 and the second filter 8, thereby unclogging them. The first outlet pipe 11 is located between the raw material tank 1 and the first filter 7. The washing solution can be discharged into the raw material tank 1 through the first outlet pipe 11. The raw material tank 1 then replenishes water to the alcohol precipitation crystallization vessel 2, thereby achieving recycling and reducing waste discharge.

[0037] To facilitate monitoring of the reaction temperature, a temperature display instrument 12 is also included. The temperature display instrument 12 is installed on the alcohol precipitation crystallization vessel 2, and the temperature display instrument 12 is connected to the control system via wired or wireless means.

[0038] In one specific embodiment, to cool the material inside the alcohol precipitation reactor, a second jacket 13 is installed outside the alcohol precipitation crystallization reactor 2. Cooling liquid enters the second jacket 13 from the lower right inlet to cool the material inside the alcohol precipitation crystallization reactor 2 and flows out from the upper left inlet. The cooling liquid can be circulating water or 7°C brine. When a first cooling rate is required, the control system controls the input of 7°C brine into the second jacket 13; when a second cooling rate is required, the control system controls the input of circulating water. When the first cooling rate is greater than the second cooling rate (i.e., a faster cooling is required), 7°C brine is input into the second jacket 13; when the cooling rate requirement is not high, circulating water is sufficient. A dual refrigerant switching temperature control system is adopted, utilizing the plant's circulating water and 7°C brine to achieve precise temperature regulation.

[0039] In another specific embodiment, in addition to the second jacket 13, the alcohol precipitation crystallization vessel 2 is also equipped with a spiral inner coil 14. The second jacket 13 is connected to the spiral inner coil 14. The cooling liquid enters from the second jacket 13 and exits from the spiral inner coil 14. Similarly, the cooling liquid can also be circulating water or 7°C brine, and different cooling liquids can be selected according to the actual situation. Further adding the spiral inner coil 14 can improve the cooling rate.

[0040] To accelerate the reaction rate and make the reaction more uniform, a motor 15 and a stirring paddle 16 are also included. The motor 15 is connected to the control system via a wired or wireless means. The output shaft of the motor 15 is rotatably connected to the stirring paddle 16, which is disposed inside the alcohol precipitation crystallization vessel 2.

[0041] Furthermore, it also includes a centrifuge 17, which is connected to the outlet of the alcohol precipitation crystallization vessel 2. When the reaction endpoint is reached in the alcohol precipitation reaction vessel, the material is fed into the centrifuge 17, and glycine wet product is obtained by centrifugation and then dried to obtain the final product.

[0042] The method of using the glycine crystallization control device provided by this utility model is as follows: Open the bottom valve of the raw material tank 1. Under the action of gravity, the ammoniation reaction liquid flows into the bag-type activated carbon filter and the precision filter for impurity filtration. At the same time, steam enters the first jacket 9 to keep the ammoniation reaction liquid warm, preventing crystals from precipitating in the first filter 7 and / or the second filter 8 and clogging the filters. If the first filter 7 and / or the second filter 8 is clogged, the primary water reverse top filter can be opened, and the washing water solution can be directly discharged into the raw material tank 1 as pre-treatment water for the ammoniation reaction. After filtration, the ammoniation reaction solution is transferred to the alcohol precipitation reactor. Once the temperature of the ammoniation reaction solution drops to the specified range, the valve of the first feed pipe 3 is opened to start stepwise alcohol dripping. The cooling rate of the alcohol precipitation reactor is controlled by the DCS interlock display of the reactor temperature and the flow rate of circulating water (or 7℃ brine). The crystallization rate of glycine crystals is controlled by the alcohol dripping rate and the stirring speed. At the same time, the pH value of the reaction solution is monitored by the DCS interlock. The pH of the material is controlled to be close to 6.0 by controlling the addition of hydrochloric acid. After the alcohol dripping is completed, the temperature is lowered. Once the material temperature drops to room temperature, it can be discharged into centrifuge 17 for centrifugation.

[0043] Finally, it should be noted that the above content is only used to illustrate the technical solution of this utility model, and is not intended to limit the scope of protection of this utility model. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of this utility model do not depart from the essence and scope of the technical solution of this utility model.

Claims

1. A glycine crystallization control device, characterized in that: Includes a raw material tank containing an ammonia reaction solution; and An alcohol precipitation crystallization vessel, which is connected to the raw material tank; and A first feed pipe and a second feed pipe, both connected to the alcohol precipitation crystallization vessel, are provided. A flow meter is installed inside the first feed pipe. A radar level gauge is installed on the alcohol precipitation crystallization vessel; and A pH meter, used to monitor the pH value of the material inside the alcohol precipitation crystallization vessel; and The control system, wherein the pipeline flow meter, the radar level gauge, the pH meter and the control system are connected via wired or wireless means; The first feed pipe is used to add methanol to the alcohol precipitation crystallization vessel, and the second feed pipe is used to add hydrochloric acid to the alcohol precipitation crystallization vessel.

2. The glycine crystallization control device according to claim 1, characterized in that: It also includes a first filter and a second filter. The first end of the first filter is connected to the raw material tank, and the second end is connected to the second filter. The second end of the second filter is connected to the alcohol precipitation crystallization vessel.

3. The glycine crystallization control device according to claim 2, characterized in that: Both the first filter and the second filter are provided with a first jacket.

4. The glycine crystallization control device according to claim 2, characterized in that: It also includes a first inlet pipe and a first outlet pipe. The first inlet pipe is located between the second filter and the alcohol precipitation crystallization vessel, and the first outlet pipe is located between the raw material tank and the first filter. The first feed pipe has a double-layer structure, and the second feed pipe has a ring structure.

5. The glycine crystallization control device according to claim 1, characterized in that: It also includes a temperature field display instrument, which is installed on the alcohol precipitation crystallization vessel and is connected to the control system via wired or wireless means.

6. The glycine crystallization control device according to claim 5, characterized in that: The alcohol precipitation crystallization vessel is equipped with a second jacket. Cooling liquid enters the second jacket from the lower right opening to cool the material inside the alcohol precipitation crystallization vessel, and flows out from the upper left opening.

7. The glycine crystallization control device according to claim 6, characterized in that: The alcohol precipitation crystallization vessel is equipped with a spiral inner coil, and the second jacket is connected to the spiral inner coil. The cooling liquid enters from the second jacket and exits from the spiral inner coil.

8. A glycine crystallization control device according to claim 6 or 7, characterized in that: The cooling liquid is either circulating water or 7°C brine. When a first cooling rate is required, the control system controls the input of 7°C brine. When a second cooling rate is required, the control system controls the input of circulating water. The first cooling rate is greater than the second cooling rate.

9. The glycine crystallization control device according to claim 1, characterized in that: It also includes a motor and a stirring paddle. The motor is connected to the control system via a wired or wireless means. The output shaft of the motor is rotatably connected to the stirring paddle, which is placed inside the alcohol precipitation crystallization vessel.

10. The glycine crystallization control device according to claim 1, characterized in that: It also includes a centrifuge, which is connected to the outlet of the alcohol precipitation crystallization vessel.

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