A continuous reaction system
By designing a continuous reaction system, using high and low concentration sulfate switching and small-particle seed semi-continuous feeding, the problems of continuous production and controllability of particle size distribution in the preparation of Prussian blue materials are solved, and high-efficiency continuous production and stable and controllable particle size distribution are achieved.
Patent Information
- Application Number
- CN202421348970.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-13
- Publication Date
- 2025-04-04
- Estimated Expiration
- 2034-06-13
AI Technical Summary
In the prior art, when preparing Prussian blue materials for sodium ion batteries, it is difficult to achieve continuous production and controllability of particle size distribution, resulting in low equipment yield and fluctuations in batch stability.
A continuous reaction system is designed, including a feeding system and a precipitation system. Through switching of high and low concentration sulfates and semi-continuous feeding of small particle seeds, the supersaturation of the slurry in the reactor is controlled to achieve a controllable particle size distribution.
The continuous production of Prussian blue materials has been achieved, with a yield rate of 100%, a stable and controllable particle size distribution, and good product consistency, which overcomes the problems of frequent discharge of equipment and batch stability fluctuations in traditional processes.
Smart Images
Figure CN222709643U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of chemical reaction devices, in particular to a continuous reaction system. Background Art
[0002] Prussian blue materials for sodium-ion batteries are mostly prepared by liquid phase intermittent process. The precipitation reaction time of a single batch is less than 24 hours. Literature reports generally show that it is less than 8 hours, and even a large number of preparation processes are 1 to 2 hours. If applied to mass production, it will increase the time for preparation steps such as frequent discharge, cleaning, adding bottom liquid and protective gas, resulting in low equipment utilization rate. And there will inevitably be fluctuations in batch stability between different batches. Unlike the continuous precipitation process of lithium battery ternary precursors, the reaction raw materials and reaction process of the Prussian blue system are neutral and no volatile complexing agents such as ammonia water are used. Therefore, it is impossible to adjust the particle size fluctuations during the precipitation process by adjusting the reaction pH value and the concentration of the complexing agent. Therefore, it is easy to cause the crystal particle size to continue to grow and cause the particle size distribution to be out of control, and it is impossible to achieve continuous and stable production with controllable particle size distribution. Improvements need to be made in this regard. Utility Model Content
[0003] The utility model aims to provide a continuous reaction system for preparing Prussian blue positive electrode materials, with an operating rate of 100% and a stable and controllable particle size distribution.
[0004] The utility model provides a continuous reaction system, comprising a feeding system and a precipitation system, wherein the feeding system comprises a plurality of raw material tanks filled with raw materials and a plurality of solution tanks filled with reaction solutions of different concentrations, and the precipitation system comprises a reaction kettle, an overflow tank and an aging tank, wherein both sides of the overflow tank are respectively connected to the reaction kettle and the aging tank;
[0005] The plurality of raw material tanks and solution tanks are in the form of high-level tanks, each of which is connected to the reactor via a pipeline, and each of which is provided with a solenoid valve and a pump between the reactor and the raw material tank and the solution tank.
[0006] Preferably, the raw material tank includes a first storage tank and a second storage tank, and the solution tank includes a third storage tank filled with a low-concentration solution and a fourth storage tank filled with a high-concentration solution.
[0007] Preferably, the pump provided between the second storage tank and the reactor is a peristaltic pump, and the pumps provided between the first storage tank, the third storage tank and the fourth storage tank and the reactor are metering pumps.
[0008] Preferably, a diaphragm pump is arranged between the overflow tank and the aging tank, and both ends of the diaphragm pump are respectively connected to the overflow tank and the aging tank by pipelines, and solenoid valves are respectively arranged between the diaphragm pump and the overflow tank and the aging tank.
[0009] Preferably, the second storage tank, the reactor, the overflow tank and the aging tank are all provided with stirring paddles, and the reactor is a multi-layer stirring structure.
[0010] Preferably, water seals are provided at the connection points between the stirring paddle and the reaction kettle, the overflow tank and the aging tank.
[0011] Preferably, the second storage tank, the reactor, the overflow tank and the aging tank are all provided with nitrogen pipes.
[0012] Preferably, an overflow port is provided in the reactor, the overflow port bends downward in the reactor, and the overflow port is connected to the overflow tank through an overflow pipe.
[0013] Preferably, the overflow pipe is arranged at an inclination, and the angle between the overflow pipe and the horizontal plane is set to A, and A≥30 degrees is satisfied.
[0014] From the above description of the utility model, it can be seen that the utility model has the following beneficial effects:
[0015] 1. By switching back and forth between high and low concentrations of sulfate, the local supersaturation of the slurry in the reactor is changed, and small-particle seeds are generated intermittently in a controllable manner. The particle size control of the semi-continuous feeding of small-particle seeds in the seed tank is used as a double insurance. The sealing and anti-oxidation effect is enhanced in the precipitation system, thereby achieving continuous and stable production with controllable particle size distribution.
[0016] 2. Nitrogen is introduced into the second storage tank to prevent oxidation of the Prussian blue seed crystals. At the same time, the stirring paddle in the second storage tank is continuously turned on at a low speed to prevent the slurry from settling.
[0017] 3. The overflow port in the reactor is a downward elbow to ensure that the liquid level is above the overflow port to prevent the overflow material from oxidizing; the overflow pipe is tilted at least 30° to the horizontal plane to prevent the overflow material from clogging the overflow port. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a schematic diagram of the overall structure of a continuous reaction system in an embodiment;
[0019] Figure 2 1 is a schematic structural diagram of a feeding system of an embodiment;
[0020] Figure 3 Schematic diagram of the structure of the precipitation system of the embodiment.
[0021] Figure numerals: 1. Feed system; 11. First storage tank; 12. Second storage tank; 13. Third storage tank; 14. Fourth storage tank; 2. Sedimentation system; 21. Reactor; 211. Overflow port; 22. Overflow tank; 23. Aging tank; 3. Solenoid valve; 4. Pump; 41. Metering pump; 42. Peristaltic pump; 5. Overflow pipe; 6. Diaphragm pump; 7. Stirring paddle; 8. Water seal; 9. Nitrogen pipe. DETAILED DESCRIPTION
[0022] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the following is a summary of the technical problems, technical solutions and beneficial effects to be solved by the present invention. Figure 1-3 It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0023] Taking the preparation of Prussian blue positive electrode material as an example,
[0024] Reference Figure 1 and Figure 2 A continuous reaction system includes a feeding system 1 and a precipitation system 2, wherein the feeding system 1 includes a plurality of raw material tanks containing raw materials and a plurality of solution tanks containing reaction solutions of different concentrations, wherein the raw material tanks include a first storage tank 11 and a second storage tank 12, and the solution tanks include a third storage tank 13 and a fourth storage tank 14. The first storage tank 11 contains a sodium ferrocyanide solution, and the second storage tank 12 contains pre-synthesized small particles of Prussian blue (D50≤2μm). The third storage tank 13 contains a low-concentration metal sulfate solution, the concentration of which is consistent with that of the sodium ferrocyanide solution, wherein the metal elements in the low-concentration metal sulfate solution include iron, manganese, nickel, zinc, copper, etc., and the proportions of different elements can be adjusted according to the product process requirements. The fourth storage tank 14 is filled with a high-concentration metal sulfate solution, the concentration of which is 4 times or more than that of the low-concentration metal sulfate solution, and can be up to 3 mol / L. Correspondingly, the feed rate of the fourth storage tank 14 is 1 / 4 or less of that of the third storage tank 13.
[0025] Reference Figure 2 and Figure 3The precipitation system 2 includes a reactor 21, an overflow tank 22 and an aging tank 23. The first storage tank 11, the second storage tank 12, the third storage tank 13 and the fourth storage tank 14 are all connected to the reactor 21 by pipelines, and electromagnetic valves 3 and pumps 4 are provided at the places where the first storage tank 11, the second storage tank 12, the third storage tank 13 and the fourth storage tank 14 are connected to the reactor 21 by pipelines, wherein the pumps 4 provided between the first storage tank 11, the third storage tank 13 and the fourth storage tank 14 and the reactor 21 are metering pumps 41, and the pumps 4 provided between the second storage tank 12 and the reactor 21 are peristaltic pumps 42. The first storage tank 11, the second storage tank 12, the third storage tank 13 and the fourth storage tank 14 are all set in the form of high-level tanks, and the electromagnetic valve 3 is used to adjust the valve opening, and the metering pump 41 or the peristaltic pump 42 is used to accurately control the feeding speed. In addition, a stirring paddle 7 is provided in the second storage tank 12, and the small particles of Prussian blue are stirred by the stirring paddle 7 to prevent the slurry from settling.
[0026] The overflow tank 22 is arranged between the reactor 21 and the aging tank 23, and the two sides of the overflow tank 22 are connected to the reactor 21 and the aging tank 23 respectively. An overflow port 211 is arranged in the reactor 21, and the overflow port 211 is bent downward in the reactor 21 to ensure that the liquid level is above the overflow port 211 to prevent the overflow material from being oxidized. The overflow port 211 is connected to the overflow tank 22 through an overflow pipe 5, and the overflow pipe 5 is kept inclined, and the angle between the overflow pipe 5 and the horizontal plane is set to A, and A≥30 degrees is satisfied, so as to prevent the overflow material from blocking the overflow port 211, and the overflowed slurry is a qualified product.
[0027] The overflow tank 22 and the aging tank 23 are connected by a pipeline, a diaphragm pump 6 is provided at the pipeline connection between the overflow tank 22 and the aging tank 23, and a solenoid valve 3 is provided at the pipeline connection between the diaphragm pump 6 and the overflow tank 22 and the aging tank 23, and the slurry is pumped 4 from the overflow tank 22 into the aging tank 23 for aging through the diaphragm pump 6 to improve the crystallinity of the Prussian blue material and make the final modification to the material morphology. In order to make the sodium ferrocyanide solution, small-particle Prussian blue, low-concentration metal sulfate solution and high-concentration metal sulfate solution fully mixed, a stirring paddle 7 is provided in the reactor 21, the overflow tank 22 and the aging tank 23, wherein the reactor 21 has a multi-layer stirring structure, and the stirring speed of the stirring paddle 7 is set to 0~1500rpm. At the same time, a water seal 8 is provided at the connection between each stirring paddle and the reactor 21, the overflow tank 22 and the aging tank 23 to prevent the phenomenon of backflow.
[0028] Reference Figure 1 , Figure 2 and Figure 3, a nitrogen pipe 9 is provided in the second storage tank 12, the reactor 21, the overflow tank 22 and the aging tank 23, and nitrogen is introduced into the bottom of the second storage tank 12 through the nitrogen pipe 9 to prevent the oxidation of small particles of Prussian blue; nitrogen is introduced into the reactor 21, the overflow tank 22 and the aging tank 23 through the nitrogen pipe 9 to prevent the oxidation of the material from causing the particle size growth rate to be out of control and the sodium content of the finished product to change. In the continuous precipitation process, the high and low concentrations of sulfate are switched back and forth to change the local supersaturation of the slurry in the reactor 21, and the small particle seeds are generated intermittently in a controllable manner, supplemented by the particle size control of the semi-continuous feeding of the small particle seeds in the seed tank, which overcomes the disadvantage that the Prussian blue system cannot control the particle size distribution by adjusting the complexing agent concentration and pH value, and strengthens the sealing and anti-oxidation effect in the precipitation system. The continuous reaction system for the preparation of Prussian blue cathode materials can achieve continuous operation of Prussian blue preparation. Continuous feeding and discharging during the production process can achieve an utilization rate of 100%. At the same time, the particle size distribution is stable and controllable, and the product consistency is good, realizing the high-efficiency continuous production of the Prussian blue system.
[0029] The specific implementation principle of the embodiment of the present application is: in order to control the particle size distribution and prevent the particles from continuing to grow during the precipitation process, the main method is to switch the high and low concentration raw materials through the sulfate storage tank. At this time, the local metal ions in the reactor 21 are in excess of the ferrocyanide ions, thereby changing the local supersaturation of the precipitation system in the reactor 21, and then controlling the generation of small particle nuclei, slowing down the growth rate of large particles, and new precipitates tend to grow preferentially on the surface of small particles, so that nucleation and growth reach a dynamic balance, and the particle size distribution presents a bimodal distribution of large and small particles. The particle size distribution parameters such as D10, D50, and D90 fluctuate back and forth within the specification requirements, thereby satisfying the stability of the particle size value of continuous production. At the same time, if large particles in the reactor 21 continue to grow uncontrollably, the small particle seeds in the second storage tank 12 can be directly pumped into the reactor 21. By controlling the pumping speed, the average particle size in the reactor 21 can be forced to be reduced in a short time. This serves as a "double insurance" for controlling the particle size distribution of the precipitation system, ensuring that the materials overflowing from the reactor 21 are qualified materials that meet the product index requirements, thereby achieving uninterrupted and stable operation of the entire precipitation system.
[0030] The utility model is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the utility model is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the utility model, or the concept and technical solution of the utility model are directly applied to other occasions without improvement, they are all protected by the utility model.
Claims
1. A continuous reaction system, characterized in that: It includes a feeding system and a precipitation system, wherein the feeding system includes a plurality of raw material tanks filled with raw materials and a plurality of solution tanks filled with reaction solutions of different concentrations, and the precipitation system includes a reactor, an overflow tank and an aging tank, wherein both sides of the overflow tank are respectively connected to the reactor and the aging tank; The plurality of raw material tanks and solution tanks are in the form of high-level tanks, each of which is connected to the reactor via a pipeline, and each of which is provided with a solenoid valve and a pump between the reactor and the raw material tank and the solution tank.
2. A continuous reaction system according to claim 1, characterized in that: The raw material tank includes a first storage tank and a second storage tank, and the solution tank includes a third storage tank filled with a low-concentration solution and a fourth storage tank filled with a high-concentration solution.
3. A continuous reaction system according to claim 2, characterized in that: The pump arranged between the second storage tank and the reactor is a peristaltic pump, and the pumps arranged between the first storage tank, the third storage tank and the fourth storage tank and the reactor are metering pumps.
4. A continuous reaction system according to claim 2, characterized in that: A diaphragm pump is arranged between the overflow tank and the aging tank, and two ends of the diaphragm pump are respectively connected with the overflow tank and the aging tank by pipelines, and electromagnetic valves are respectively arranged between the diaphragm pump and the overflow tank and the aging tank.
5. A continuous reaction system according to claim 2, characterized in that: The second storage tank, the reactor, the overflow tank and the aging tank are all provided with stirring paddles, and the reactor is a multi-layer stirring structure.
6. A continuous reaction system according to claim 5, characterized in that: The connection places of the stirring paddle with the reaction kettle, the overflow tank and the aging tank are respectively provided with water seals.
7. A continuous reaction system according to claim 2, characterized in that: The second storage tank, the reactor, the overflow tank and the aging tank are all provided with nitrogen pipes.
8. A continuous reaction system according to claim 2, characterized in that: An overflow port is arranged in the reactor, the overflow port bends downward in the reactor, and the overflow port is connected to the overflow tank through an overflow pipe.
9. A continuous reaction system according to claim 8, characterized in that: The overflow pipe is tilted, and the angle between the overflow pipe and the horizontal plane is set to A, and A≥30 degrees.