Continuous production device for EDTA (ethylene diamine tetraacetic acid) condensation reaction
By using devices such as a reaction deammoniation tower and a shell-and-tube heat exchanger in the EDTA condensation reaction, the problems of product quality and yield caused by the failure to discharge ammonia in a timely manner were solved, achieving efficient and energy-saving continuous production and reducing production costs and equipment footprint.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 石家庄杰克化工有限公司
- Filing Date
- 2025-04-07
- Publication Date
- 2026-05-26
AI Technical Summary
In existing EDTA condensation reactions, the failure to promptly remove ammonia gas leads to a decline in product quality and yield. The equipment also has a large footprint, high production costs and energy consumption, and high labor intensity.
The continuous production unit employs a reaction deammoniation tower, a shell-and-tube heat exchanger, a feeding circulation pump, and a multi-stage pump. Ammonia gas is rapidly discharged through the shell-and-tube heat exchanger, and the raw materials are heated using the heat inside the reaction deammoniation tower. The mixer then rapidly mixes the raw materials, achieving continuous production.
It improves the timeliness of ammonia discharge, enhances product quality and yield, reduces production costs and energy consumption, and minimizes equipment footprint and labor intensity.
Smart Images
Figure CN224271205U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of chemical equipment technology, specifically relating to a continuous production device for EDTA condensation reaction. Background Technology
[0002] EDTA (ethylenediaminetetraacetic acid) is an important chelating agent with significant applications in photographic chemicals, water treatment agents, chemical refining (such as cystine), detergents, textile auxiliaries, leather chemicals, paper chemicals, pharmaceuticals, synthetic rubber, and micronutrient fertilizer production.
[0003] The main production processes for EDTA condensation reaction include the sodium cyanide method and the chloroacetic acid method. Currently, the sodium cyanide method is mostly used, in which ethylenediamine, formaldehyde, and sodium cyanide undergo a condensation reaction under alkaline conditions to produce EDTA-4Na and ammonia. If the byproduct ammonia is not discharged in time, it will cause side reactions, leading to a decline in product quality and a decrease in yield. Therefore, timely and efficient ammonia discharge is a key control factor for improving reaction quality.
[0004] The current problem with EDTA condensation reactions is:
[0005] (1) The measures adopted in industrial production are vacuum ammonia removal and direct steam introduction into the condensation reactor to enhance ammonia removal. Although this method improves the heat exchange efficiency of steam and has a certain ammonia removal effect, ammonia is continuously generated during the reaction process, and the residence time of the generated ammonia in the liquid phase is not effectively shortened, so the problem is not solved.
[0006] (2) Due to the limitations of the current equipment, the production capacity is not high. In order to solve the problem of timely discharge of ammonia during the reaction process, multiple equipment need to be configured, and more land area is needed to configure the equipment. This not only increases the production cost and energy consumption, but also significantly increases the labor intensity of employees. Utility Model Content
[0007] This utility model provides a continuous production device for EDTA condensation reaction, which aims to improve the ammonia removal effect and timeliness, improve the product quality after EDTA condensation reaction, and at the same time save land, reduce production costs, energy consumption and labor intensity.
[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A continuous production apparatus for EDTA condensation reaction is provided, comprising: a reaction deammoniation tower, a first heat exchanger, a second heat exchanger, and a mixer. A tube-and-shell heat exchanger is installed at the top of the reaction deammoniation tower, and an ammonia discharge pipe is installed at the top of the tube-and-shell heat exchanger. The first heat exchanger is connected to a first feed pipe, and the material heated by the first heat exchanger enters the mixer through a first connecting pipe. The second heat exchanger is connected to a second feed pipe, and the material heated by the second heat exchanger enters the mixer through the second connecting pipe, where it is mixed with the material heated by the first heat exchanger. The mixer is connected to the reaction deammoniation tower through a mixture feed pipe.
[0009] The bottom of the reaction deammoniation tower is provided with a collection pipe, and a feeding circulation pump is provided on the collection pipe; the high-temperature reaction liquid collected from the bottom of the reaction deammoniation tower by the feeding circulation pump is partially fed into the first heat exchanger through the first heat exchange pipe for heat exchange, partially fed into the second heat exchanger through the second heat exchange pipe for heat exchange, and partially fed into the mixer through the circulation connecting pipe for material mixing.
[0010] The first heat exchanger is also provided with a first reaction liquid discharge pipe for discharging the cooled reaction liquid after heat exchange, and the second heat exchanger is also provided with a second reaction liquid discharge pipe for discharging the cooled reaction liquid after heat exchange.
[0011] In one feasible approach, both the first heat exchanger and the second heat exchanger are pipe heat exchangers.
[0012] In one feasible manner, the mixer is a multistage pump with multiple impellers connected in series.
[0013] In one possible implementation, the circulating connecting pipe is connected to the first connecting pipe.
[0014] In one possible implementation, the first reaction liquid discharge pipe and the second reaction liquid discharge pipe merge into a main reaction liquid discharge pipe.
[0015] In one possible implementation, an ethylenediamine feed pipe, a sodium cyanide feed pipe, and a liquid alkali feed pipe are arranged side by side on the first feed pipe.
[0016] In one feasible approach, a temperature sensor is provided at the lower end of the reaction deammoniation tower.
[0017] In one possible implementation, control valve assemblies are provided on the first feed pipe, the second feed pipe, the first heat exchange pipe, the second heat exchange pipe, and the circulation connecting pipe.
[0018] In one possible implementation, the control valve assembly includes a flow meter disposed on the first feed pipe and an electrically controlled regulating valve, the electrically controlled regulating valve being interlocked with the flow meter.
[0019] In one possible implementation, the first feed pipe is provided with a bypass pipe that bypasses the control valve assembly; the bypass pipe is provided with the bypass control valve.
[0020] The continuous production device for EDTA condensation reaction provided by this utility model has the following advantages compared with the prior art: (1) Improved ammonia removal efficiency and timeliness. Compared with the current problem of poor ammonia removal efficiency, the reaction deammoniation tower adopted in this application takes advantage of the large surface area of the packing in the distillation tower, which is conducive to the discharge of ammonia; the top is equipped with a tube heat exchanger with a circulating water inlet pipe and a circulating water outlet pipe, which can ensure the full discharge of by-product ammonia, improve the ammonia removal efficiency and timeliness, and at the same time, the reduction of ammonia content also greatly reduces the cost of subsequent wastewater treatment; the tube heat exchanger can also cool the ethylenediamine entrained in the ammonia, so that the ethylenediamine flows back to the reaction deammoniation tower under its own weight, preventing the loss of ethylenediamine entrained in the ammonia and causing the problem of low yield.
[0021] (2) Ethylenediamine, liquid alkali and sodium cyanide do not react with each other. Therefore, the three raw materials are first heated and mixed by a heat exchanger. Formaldehyde is heated by a second heat exchanger. The two heat exchangers have both heat exchange and mixing functions. The three mixtures after heat exchange are combined with formaldehyde in the mixing tank according to the reaction ratio. The circulating reaction liquid taken from the reaction deammoniation tower is used as a carrier. The mixture is quickly mixed evenly by the mixing tank and then enters the reaction deammoniation tower for reaction. The ammonia gas released during the reaction is effectively separated from the reactants in the tower, which reduces the degree of side reaction and improves the quality of the reaction liquid.
[0022] (3) By using the feeding circulation pump as the carrier for raw material mixing and flow, the flow rate of raw materials in the mixer is guaranteed, the residence time of raw materials in the equipment including the mixer is short, and most of the reaction is completed in the reaction deammoniation tower, which shortens the reaction time and improves the reaction efficiency.
[0023] (4) Compared with the existing batch production process, this application uses a mixer instead of a traditional reactor and uses two heat exchangers to heat the added materials, which simplifies the production equipment, reduces the floor space, and lowers the production cost; the reaction liquid taken from the reaction deammoniation tower is used to exchange heat with the raw materials in a countercurrent manner, which makes full use of and recovers heat and reduces energy consumption.
[0024] (5) By using a feeding circulation pump, two heat exchangers and a mixer to circulate the feed to the reaction deammoniation tower, continuous production can be achieved, thereby reducing the labor intensity of employees. Attached Figure Description
[0025] Figure 1 A schematic diagram of the structure of a continuous production apparatus for EDTA condensation reaction provided in an embodiment of this utility model;
[0026] Explanation of reference numerals in the attached figures:
[0027] 1. Reaction deammoniation tower; 2. Feeding circulation pump; 3. Second heat exchanger; 4. First heat exchanger; 5. Mixer; 6. Shell and tube heat exchanger; 7. Ammonia discharge pipe; 8. Mixture feed pipe; 9. Circulation connecting pipe; 10. Second connecting pipe; 11. First connecting pipe; 12. Second heat exchange tube; 13. First heat exchange tube; 14. Ethylenediamine feed pipe; 15. Sodium cyanide feed pipe; 16. Liquid alkali feed pipe; 17. Second feed pipe; 18. Total discharge pipe of reaction liquid; 19. First reaction liquid discharge pipe; 20. Second reaction liquid discharge pipe; 21. Outlet pipe; 22. Temperature sensor; 23. Bypass pipe; 24. Flow meter; 25. Bypass control valve; 26. Electric regulating valve; 27. First feed pipe. Detailed Implementation
[0028] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.
[0029] Please see Figure 1 The continuous production apparatus for EDTA condensation reaction provided by this utility model will now be described. The continuous production apparatus for EDTA condensation reaction includes a reaction deammoniation tower 1, a first heat exchanger 4, a second heat exchanger 3, and a mixer 5. A tube-and-shell heat exchanger 6 is installed at the top of the reaction deammoniation tower 1, and an ammonia discharge pipe 7 is installed at the top of the tube-and-shell heat exchanger 6. The first heat exchanger 4 is connected to a first feed pipe 27, and the material heated by the first heat exchanger 4 enters the mixer 5 through a first connecting pipe 11. The second heat exchanger 3 is connected to a second feed pipe 17, and the material heated by the second heat exchanger 3 enters the mixer 5 through a second connecting pipe 10, where it is mixed with the material heated by the first heat exchanger 4. The mixer 5 is connected to the reaction deammoniation tower 1 through a mixture feed pipe 8.
[0030] A collection pipe 21 is installed at the bottom of the reaction deammoniation tower 1, and a feeding circulation pump 2 is installed on the collection pipe 21. The high-temperature reaction liquid collected from the bottom of the reaction deammoniation tower 1 by the feeding circulation pump 2 is partially fed into the first heat exchanger 4 through the first heat exchange pipe 13 for heat exchange, partially fed into the second heat exchanger 3 through the second heat exchange pipe 12 for heat exchange, and partially fed into the mixer 5 through the circulation connecting pipe 9 for material mixing. The first heat exchanger 4 is also provided with a first reaction liquid discharge pipe 19 for discharging the cooled reaction liquid after heat exchange, and the second heat exchanger 3 is also provided with a second reaction liquid discharge pipe 20 for discharging the cooled reaction liquid after heat exchange.
[0031] Based on the implementation of the above technical solution, this device solves the problems of low ammonia removal efficiency, equipment redundancy, and high energy consumption in traditional EDTA condensation reactions by optimizing the reaction and mass transfer process and integrating the production process. It shows significant advantages in industrial applications, specifically in the following aspects:
[0032] The continuous production device for EDTA condensation reaction provided by this utility model has the following advantages compared with the prior art: (1) Improved ammonia removal effect and timeliness. Compared with the current problem of poor ammonia removal effect, this application sets up a tube heat exchanger 6 with a circulating water inlet pipe and a circulating water outlet pipe at the top of the reaction deammoniation tower 1. The tube heat exchanger 6 can quickly exchange the heat generated by the reaction, which can ensure that the by-product ammonia gas is fully discharged directly from the ammonia gas outlet pipe at the top, thus improving the ammonia removal effect and timeliness. At the same time, the reduction of ammonia content also greatly reduces the cost of subsequent wastewater treatment. The ethylenediamine condensed by the tube heat exchanger 6 can be completely returned to the reaction deammoniation tower 1 under its own weight, avoiding the loss of raw materials.
[0033] (2) Ethylenediamine A, sodium cyanide B and liquid alkali C do not react with each other. Therefore, the three raw materials are heated and mixed by a heat exchanger. Formaldehyde D is heated by a second heat exchanger 3. The two heat exchangers have both heat exchange and mixing functions. The three mixtures after heat exchange are combined with formaldehyde in the mixing tank 5 according to the reaction ratio. The reaction liquid taken from the reaction deammoniation tower 1 is used as a carrier. The mixture is quickly mixed evenly by the mixing tank 5 and then enters the reaction deammoniation tower 1 for reaction. The ammonia gas F released during the reaction is effectively separated from the reactants in the tower, which reduces the degree of side reaction and improves the quality of the reaction liquid.
[0034] Explained, the reaction of the mixture entering the reaction deammoniation tower 1 releases a large amount of heat, thereby forming a high-temperature reaction liquid. The high-temperature reaction liquid taken from the bottom of the reaction deammoniation tower 1 is generally between 98°C and 100°C, while the raw materials entering from each feed pipe are generally at room temperature. Therefore, this application directly utilizes the heat generated in the reaction deammoniation tower 1 to raise the temperature of the raw materials, which not only realizes the recovery and utilization of heat and achieves energy saving and consumption reduction, but also improves the reaction effect of the raw materials in the reaction deammoniation tower 1.
[0035] (3) The reaction liquid collected by the feeding circulation pump 2 is divided into three paths. Two paths are connected to the heat exchanger to heat up the raw materials in the heat exchanger. One path serves as a carrier for mixing and flowing the raw materials, ensuring the flow rate of the raw materials in the mixer. This results in a short residence time of the raw materials in the equipment, including the mixer 5. Most of the reaction is completed in the reaction deammoniation tower 1, which shortens the reaction time and improves the reaction efficiency.
[0036] (4) Compared with the existing batch production process, this application uses a mixer 5 instead of a traditional reactor and two heat exchangers to heat the added materials, which simplifies the production equipment, reduces the floor space, and lowers the production cost; the reaction liquid taken from the reaction deammoniation tower 1 is used to exchange heat with the raw materials in a countercurrent manner, which makes full use of and recovers heat and reduces energy consumption.
[0037] (5) By using the feeding circulation pump 2, two heat exchangers and mixer 5 to circulate the feed to the reaction deammoniation tower 1, continuous production can be achieved, thereby reducing the labor intensity of employees.
[0038] (6) After the various raw materials are fully mixed by the mixer 5, they are fed into the reaction deammoniation tower 1, which not only ensures the reaction time of the stripping section, but also utilizes the separation and distillation function of the rectification section, which is conducive to improving the reaction quality.
[0039] In some embodiments, see Figure 1 As shown, both the first heat exchanger 4 and the second heat exchanger 3 are pipe heat exchangers. Using pipe heat exchangers allows the extracted reaction liquid to exchange heat counter-currently with the raw materials, which increases the temperature of the raw materials while decreasing the temperature of the extracted reaction liquid, thus fully utilizing heat, improving energy efficiency, and reducing energy consumption.
[0040] In some embodiments, see Figure 1 As shown, the mixer 5 is a multistage pump with multiple impellers connected in series. The high-speed rotating impellers ensure thorough mixing of materials at both the macroscopic and microscopic levels, allowing them to pass quickly through the mixer 5, thus improving reaction efficiency and quality, and shortening reaction time. Furthermore, this integrated mixer 5 has a small footprint, saving space.
[0041] In some embodiments, see Figure 1 As shown, the circulation connecting pipe 9 is connected to the first connecting pipe 11, and the reaction liquid is first mixed with the three mixtures before entering the mixer 5.
[0042] In some embodiments, see Figure 1 As shown, the first reaction liquid discharge pipe 19 and the second reaction liquid discharge pipe 20 converge into the main reaction liquid discharge pipe 18, which reflects the saving of materials and the integrated layout, reducing production costs.
[0043] In some embodiments, see Figure 1 As shown, the first feed pipe 27 is equipped with an ethylenediamine feed pipe 14, a sodium cyanide feed pipe 15, and a liquid alkali feed pipe 16 arranged in parallel, which reflects the saving of materials and the integrated layout, reducing production costs.
[0044] In some embodiments, see Figure 1 As shown, a temperature sensor 22 is installed at the lower end of the reaction deammoniation tower 1, which can collect the reaction temperature inside the tower in real time, which is beneficial for controlling production quality.
[0045] In some embodiments, see Figure 1 As shown, control valve assemblies are installed on the first feed pipe 27, the second feed pipe 17, the first heat exchange pipe 13, the second heat exchange pipe 12, and the circulation connecting pipe 9. By cooperating with the control system of the entire unit, automated operation can be achieved, reducing the labor intensity of employees. Since the ethylenediamine feed pipe 14, the sodium cyanide feed pipe 15, and the liquid alkali feed pipe 16 are connected in parallel to the first feed pipe 27, control valve assemblies are specifically installed on each of these three pipes.
[0046] In some embodiments, see Figure 1 As shown, the control valve assembly includes a flow meter 24 and an electric regulating valve 26 installed on the first feed pipe 27; the flow meter 24 and the electric regulating valve 26 are interlocked. Specifically, the flow meter 24 and the electric regulating valve 26 are interlocked through the device's control system. The control system collects the flow signal of the raw material in the pipe monitored in real time by the flow meter 24 and adjusts the opening of the electric regulating valve 26 to meet the requirements of each raw material ratio and ensure product quality. Such control valve assemblies are installed on the ethylenediamine feed pipe 14, the sodium cyanide feed pipe 15, the liquid alkali feed pipe 16, the first heat exchange pipe 13, the second heat exchange pipe 12, and the circulating connecting pipe 9. Through the cooperation of the control valve assembly, temperature sensor, and flow meter, automated operation can be achieved, reducing the labor intensity of employees. The control valve assembly also includes ball valves installed at both ends of the electric regulating valve 26. When the electric regulating valve malfunctions, the manually controlled ball valves can be used to cut off or regulate the flow in the pipeline, avoiding the risks associated with electric regulating valve and circuit failures.
[0047] In some embodiments, see Figure 1 As shown, a bypass pipe 23 of the bypass control valve group is installed on the first feed pipe 27; a bypass control valve 25 is installed on the bypass pipe 23. The bypass pipe 23 is used to maintain material flow when the control valve group fails. When the control valve group fails, continuous production can still be achieved through the bypass pipe 23, avoiding production stoppages during failures and maximizing the guarantee of continuous production operation. The bypass control valve 25 can be a ball valve or a gate valve, etc.
[0048] The EDTA condensation reaction process using this apparatus is as follows:
[0049] Ethylenediamine A, sodium cyanide B, and liquid alkali C are mixed in proportion in the first heat exchanger 4 by the electric regulating valves and flow meters 24 on their respective feed pipes, and exchange heat with the tetrasodium reaction solution collected from the reaction deammoniation tower 1 to raise the temperature; formaldehyde D enters the second heat exchanger 3 through the second feed pipe 17, and exchanges heat with the externally collected tetrasodium reaction solution in the second heat exchanger 3 to raise the temperature. The mixture of ethylenediamine A, sodium cyanide B, and liquid alkali C, after heat exchange, is combined with formaldehyde D in the reaction ratio before mixer 5. Using the circulating tetrasodium reaction solution as a carrier, it is quickly mixed evenly through mixer 5 and then enters the reaction deammoniation tower 1 for reaction. The top of the tower is equipped with a shell and tube heat exchanger 6, which is cooled by circulating water pipes through inlet and outlet pipes. This can cool the ethylenediamine entrained in the ammonia gas. The cooled ethylenediamine can be completely returned to the reaction deammoniation tower to prevent the loss of ethylenediamine. The by-product ammonia gas F can be discharged directly from the ammonia gas discharge pipe 7 in a timely and sufficient manner. The tetrasodium reaction solution E, after heat exchange and cooling, is discharged from the total reaction solution discharge pipe 18.
[0050] Under the same raw material ratio, the following statistics are based on the current production process and data from this device: the impurity of EDTA tetrasodium liquid aminotriacetic acid produced by this device is reduced from 3% to 1%, the main liquid phase content is over 96%, and the product productivity is increased by 1%; the ammonia content of the by-product is reduced from the current 1000ppm to 100ppm.
[0051] Explained, ppm is an abbreviation for parts per million, which indicates the proportion of a certain component in a total quantity. In chemistry, ppm is often used to express the concentration of a solute in a solution; for example, 1 ppm means that there is 1 part of solute in one million parts of solution.
[0052] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.
[0053] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. An apparatus for continuous production of EDTA condensation reaction, characterized by, include: The reaction deammonia removal tower (1), a first heat exchanger (4), a second heat exchanger (3), and a mixer (5) are provided. A tube heat exchanger (6) is provided at the top of the reaction deammonia removal tower (1), and an ammonia discharge pipe (7) is provided at the top of the tube heat exchanger (6). The first heat exchanger (4) is connected to a first feed pipe (27), and the material that has been heated by the first heat exchanger (4) enters the mixer (5) through a first connecting pipe (11). The second heat exchanger (3) is connected to a second feed pipe (17), and the material that has been heated by the second heat exchanger (3) enters the mixer (5) through a second connecting pipe (10) and is mixed with the material that has been heated by the first heat exchanger (4) in the mixer (5). The mixer (5) is connected to the reaction deammonia removal tower (1) through a mixture feed pipe (8). The bottom of the reaction deammoniation tower (1) is provided with a collection pipe (21), and a feeding circulation pump (2) is provided on the collection pipe (21); the high-temperature reaction liquid collected from the bottom of the reaction deammoniation tower (1) by the feeding circulation pump (2) is partially fed into the first heat exchanger (4) through the first heat exchange pipe (13) for heat exchange, partially fed into the second heat exchanger (3) through the second heat exchange pipe (12) for heat exchange, and partially fed into the mixer (5) through the circulation connecting pipe (9) for material mixing; The first heat exchanger (4) is also provided with a first reaction liquid discharge pipe (19) for discharging the cooled reaction liquid after heat exchange, and the second heat exchanger (3) is also provided with a second reaction liquid discharge pipe (20) for discharging the cooled reaction liquid after heat exchange.
2. The continuous production apparatus for EDTA condensation reaction according to claim 1, wherein Both the first heat exchanger (4) and the second heat exchanger (3) are pipe heat exchangers.
3. The continuous production apparatus for EDTA condensation reaction according to claim 1, wherein The mixer (5) is a multistage pump with multiple impellers connected in series.
4. The continuous production apparatus for EDTA condensation reaction according to claim 1, wherein The circulating connecting pipe (9) is connected to the first connecting pipe (11).
5. The continuous production apparatus for EDTA condensation reaction according to claim 1, wherein The first reaction liquid discharge pipe (19) and the second reaction liquid discharge pipe (20) converge into the main reaction liquid discharge pipe (18).
6. The continuous production apparatus for the EDTA condensation reaction as described in claim 1, characterized in that, The first feed pipe (27) is provided with an ethylenediamine feed pipe (14), a sodium cyanide feed pipe (15) and a liquid alkali feed pipe (16) arranged in parallel.
7. The continuous production apparatus for the EDTA condensation reaction as described in claim 1, characterized in that, A temperature sensor (22) is installed at the lower end of the reaction deammoniation tower (1).
8. The continuous production apparatus for the EDTA condensation reaction as described in claim 1, characterized in that, Control valve groups are provided on the first feed pipe (27), the second feed pipe (17), the first heat exchange pipe (13), the second heat exchange pipe (12), and the circulation connecting pipe (9).
9. The continuous production apparatus for the EDTA condensation reaction as described in claim 8, characterized in that, The control valve assembly includes a flow meter (24) and an electric regulating valve (26) disposed on the first feed pipe (27), and the electric regulating valve (26) is interlocked with the flow meter (24).
10. The continuous production apparatus for the EDTA condensation reaction as described in claim 9, characterized in that, The first feed pipe (27) is provided with a bypass pipe (23) that bypasses the control valve group; the bypass pipe (23) is provided with a bypass control valve (25).