A perfluoro-1,2-epoxy-pentane epoxidation reaction system based on wastewater recycling

Abstract

The utility model relates to a kind of perfluoro-1,2-epoxide pentane epoxidation reaction systems based on wastewater recycling, the system includes reactant mixing component, high-concentration sodium hypochlorite preparation system, epoxide reactor and separator. Wherein, with wastewater recycling mechanism as core: the sodium hypochlorite, sodium chloride wastewater containing second separator discharged is directly sent into sodium preparation kettle, and mixed with the solid sodium hypochlorite added by solid sodium hypochlorite closed feeding device, and is prepared into 15%~20% high-concentration sodium hypochlorite solution and recycled to reaction system;Chloride generated by reaction is directly packaged after centrifugal separation.The utility model can solve the problems of unstable sodium hypochlorite concentration, high wastewater treatment cost, large equipment investment and high energy consumption in the existing process system.

Description

[Technical Field]

[0001] This utility model relates to the field of chemical production equipment technology, specifically to a perfluoroepoxypentane epoxidation reaction system based on wastewater recycling. [Background Technology]

[0002] Perfluoroepoxypentane (perfluoro-2,3-epoxy-2-methyl-pentane) is an intermediate in the synthesis of perfluorohexanone, produced by the oxidation of perfluoro-2-methyl-2-pentene (D2). Current technology primarily employs a batch reactor process: D2 is mixed with acetonitrile solvent and a 10%-13% sodium hypochlorite solution, and reacted at 0-5°C for 5-10 hours. The reaction product is then separated in a separatory tank to obtain the epoxide (perfluoroepoxypentane), wastewater containing sodium hypochlorite / sodium chloride, and the solvent. The specific process is as follows:

[0003] (1) Control the temperature of the epoxidation reactor to 0-5℃ and open the tail gas vent pipe;

[0004] (2) After measuring the solvent and the purchased 13% sodium hypochlorite solution in the solvent metering tank and the sodium hypochlorite metering tank respectively, put them into the epoxy reactor and start stirring.

[0005] (3) After the raw material D2 is metered in the D2 metering tank, it is slowly added dropwise to the epoxidation reactor. After the reaction is carried out for 5 to 10 hours, a sample is taken for analysis to determine whether the reaction endpoint has been reached.

[0006] (4) After the reaction is qualified, the epoxy liquid is put into the first layering tank, the epoxy is separated from the bottom of the tank, and the aqueous phase and solvent coming out from the top enter the second layering tank. The aqueous phase containing sodium chloride and sodium hypochlorite is separated from the bottom of the tank, and the solvent at the top of the tank is returned to the solvent metering tank for reuse.

[0007] (5) The aqueous phase enters the wastewater evaporation concentration crystallization system. After dehydration by multi-effect evaporation or MVR system, the crystallized salt is packaged and the wastewater enters the sewage treatment.

[0008] Therefore, this process has significant drawbacks:

[0009] Production instability: Sodium hypochlorite is easily decomposed, and its concentration is unstable. Purchased sodium hypochlorite has a concentration of only 10%, while production requires a high concentration (above 13%). At the same time, there is a significant loss of available chlorine during storage (approximately 30% loss after 12 hours and approximately 50% loss after 36 hours), leading to fluctuations in reaction conversion rate and unstable product quality.

[0010] High equipment investment: To maintain the sodium hypochlorite concentration, a dedicated storage device is required, and multi-effect evaporation or MVR system processing is needed, which increases equipment investment by more than 40% and requires a large area.

[0011] Low raw material utilization: Sodium hypochlorite is in excess by more than 50%, and 5%-8% of unreacted sodium hypochlorite remains in the wastewater, resulting in serious waste of raw materials.

[0012] High energy consumption: The reaction requires -10℃ chilled water to maintain the low temperature (reaction temperature 0-5℃), resulting in high refrigeration energy consumption.

[0013] Epoxide yield limitations: The reaction rate is slow at low temperatures, and the sodium hypochlorite concentration is low, resulting in a long reaction time and low conversion rate.

[0014] Safety risks: The existing layered tanks have a long residence time, which may cause the residual sodium hypochlorite to decompose and exotherm, leading to overheating risks, as well as sodium chloride crystallization that may clog the pipeline.

[0015] High cost of treating waste: For every ton of epoxide produced, 4 to 6 tons of saline wastewater are generated. Waste salt is obtained through evaporation and crystallization, which consumes a large amount of steam. The cost of treating wastewater per ton of epoxide increases by 400-900 yuan, resulting in high production costs. [Summary of the Invention]

[0016] The technical problem to be solved by this utility model is to provide a perfluoroepoxypentane epoxidation reaction system based on wastewater recycling, which can solve the problems of unstable sodium hypochlorite concentration, high wastewater treatment cost, large equipment investment and high energy consumption caused by the unreasonable structure of the existing process system.

[0017] This utility model is implemented as follows:

[0018] A perfluoropentane epoxidation reaction system based on wastewater recycling, the reaction system structure comprising:

[0019] The reactant mixing assembly includes a high-concentration sodium hypochlorite preparation system, a new acetonitrile solvent feed pipe, an acetonitrile solvent intermediate tank, a D2 feed pipe, a sodium hypochlorite metering pump, a solvent metering pump, a D2 metering pump, and a mixer; the high-concentration sodium hypochlorite preparation system includes a solid sodium hypochlorite closed feeding device, a sodium hypochlorite preparation kettle, a sodium chloride centrifuge, a high-concentration sodium hypochlorite intermediate tank, and a sodium chloride packaging system;

[0020] The solid sodium hypochlorite closed feeding device is connected to the inlet of the sodium hypochlorite preparation kettle, the outlet of the sodium hypochlorite preparation kettle is connected to the sodium chloride centrifuge, and the light phase outlet of the sodium chloride centrifuge is connected to the high-concentration sodium hypochlorite intermediate tank.

[0021] The high-concentration sodium hypochlorite intermediate tank is connected to the sodium hypochlorite metering pump via a high-concentration sodium hypochlorite feed pipe. The new acetonitrile solvent is connected to the acetonitrile solvent intermediate tank via a new acetonitrile solvent feed pipe. The acetonitrile solvent intermediate tank is connected to the solvent metering pump via a pipe. D2 is connected to the D2 metering pump via a D2 feed pipe. The sodium hypochlorite metering pump, the solvent metering pump, and the D2 metering pump are each connected to the mixer via pipes.

[0022] An epoxy reactor, wherein the inlet of the epoxy reactor is connected to the outlet of the mixer;

[0023] The separator includes a first separator and a second separator, which are connected in series. The inlet of the first separator is connected to the reactant outlet of the epoxy reactor. The epoxide in the first separator is discharged from the epoxy discharge pipe through the heavy phase outlet. The solvent and aqueous phase material in the first separator are connected to the bottom of the second separator through the solvent / aqueous phase discharge pipe through the light phase outlet. The solvent in the second separator is discharged from the light phase outlet through the solvent circulation pipe and sent to the acetonitrile solvent intermediate tank.

[0024] Wastewater containing sodium hypochlorite and sodium chloride in the second separator is sent to the sodium hypochlorite preparation vessel through the aqueous phase discharge pipe and mixed with solid sodium hypochlorite fed by the solid sodium hypochlorite feeding device.

[0025] Furthermore, both the first separator and the second separator are closed centrifuges or stratification tanks.

[0026] Furthermore, the heavy phase outlet of the sodium chloride centrifuge is connected to the sodium chloride packaging system.

[0027] Furthermore, the solid sodium hypochlorite closed feeding device has the following structure: it includes a cylinder, a conical feeding hopper at the bottom of the cylinder, a stirring mechanism at the upper part of the inner cavity of the cylinder, a frame below the stirring mechanism, a screen installed inside the frame, a spring connecting the lower end of the frame to a fixed block, a vibration motor installed on the frame, an inclined guide plate below the screen, a speed adjustment mechanism below the guide plate, the speed adjustment mechanism including a roller, multiple tilting plates on the side of the roller, one end of the roller penetrating the side wall of the feeding hopper and connected to a feeding motor, a discharge pipe installed at the side opening of the feeding hopper, a guiding mechanism inside the discharge pipe, and a feeding pipe at the bottom opening of the discharge pipe.

[0028] Furthermore, the bottom of the cylinder is provided with multiple support columns; the top of the cylinder is detachably connected to a top cover, and a feed inlet is opened in the middle of the top cover, while an openable sealing plate is provided inside the feed inlet; an observation window is provided on the side of the cylinder.

[0029] Furthermore, the stirring mechanism includes a rotating shaft, with multiple stirring paddles disposed on the outer side of the rotating shaft, and the end of the rotating shaft extending through to the outside of the cylinder and being connected to the stirring motor for transmission.

[0030] Furthermore, the material guiding mechanism includes a discharge shaft, on which multiple feeding plates are equally spaced, and one end of the discharge shaft is connected to a feeding motor.

[0031] Furthermore, a solenoid valve is installed on the feed pipe.

[0032] This utility model has the following advantages:

[0033] (1) Clean and environmentally friendly process: The process of this utility model uses wastewater to prepare sodium hypochlorite solution, reducing high-salt wastewater by 4 to 6 tons per ton of product, and does not generate wastewater. The process is clean and environmentally friendly.

[0034] (2) Energy consumption is greatly reduced: This utility model directly uses the saline wastewater after the reaction to prepare sodium hypochlorite solution, avoiding the use of a high-salt water concentration and crystallization system, saving 0.5 to 2.5 tons of steam per ton of product, and greatly reducing energy consumption;

[0035] (3) The utilization rate of sodium hypochlorite raw materials is increased by 50%: The wastewater from this process is reused to prepare sodium hypochlorite solution. More than 50% of the unreacted sodium hypochlorite in the wastewater is reused, and the utilization rate of sodium hypochlorite is greatly improved.

[0036] (4) Equipment investment saved by 30%: This utility model uses the wastewater after the reaction to prepare a 15% to 20% sodium hypochlorite solution. The sodium chloride generated by the reaction is directly precipitated by the common ion effect. The waste salt can be obtained by centrifugation, avoiding the use of a multi-effect evaporation crystallization system, which greatly simplifies the process and saves a lot of investment and operating costs.

[0037] (5) More stable reaction conditions and higher conversion rate: This utility model uses solid sodium hypochlorite and wastewater to prepare a high-concentration sodium hypochlorite solution. The concentration can be increased to 15% to 20% according to process requirements, and it can be used immediately after preparation. This not only increases the concentration of sodium hypochlorite solution, but also avoids the problem of effective chlorine loss during storage, thereby improving the stability and conversion rate of product quality.

[0038] (6) The closed feeding device for solid sodium hypochlorite has a reasonable structural design and can realize the stirring, mixing, vibration screening, rate control and automatic feeding of solid sodium hypochlorite material. It solves the problems of easy material agglomeration leading to material blockage, lack of screening mechanism introducing impurities, uncontrollable feeding rate and need for manual feeding in the existing device, and improves feeding efficiency and material feeding accuracy. [Attached Image Description]

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0040] Figure 1 This is a schematic diagram of a perfluoroepoxide epoxidation reaction system based on wastewater recycling according to this utility model.

[0041] Figure 2This is a schematic diagram of a closed feeding device for solid sodium hypochlorite in a perfluoroepoxy pentane epoxidation reaction system based on wastewater recycling, according to this utility model.

[0042] Figure 3 This is a schematic diagram of the internal structure of the closed feeding device for solid sodium hypochlorite of this utility model.

[0043] Figure 4 This is a schematic diagram of the rate adjustment mechanism of the closed feeding device for solid sodium hypochlorite of this utility model.

[0044] The numbers in the image are as follows:

[0045] 100-Reactant mixing assembly, 101-High-concentration sodium hypochlorite preparation system, 102-New acetonitrile solvent feed pipe, 103-Acetonitrile solvent intermediate tank, 104-D2 feed pipe, 105-Sodium hypochlorite metering pump, 106-Solvent metering pump, 107-D2 metering pump, 108-Mixer, 109-Solid sodium hypochlorite closed feeding device, 110-Sodium hypochlorite preparation kettle, 111-Sodium chloride centrifuge, 112-High-concentration sodium hypochlorite intermediate tank, 113-Sodium chloride packaging system, 114-High-concentration sodium hypochlorite feed pipe;

[0046] 200-Epoxy Reactor;

[0047] 300 - Separator, 301 - First separator, 302 - Second separator;

[0048] 401 - Epoxy discharge pipe, 402 - Solvent circulation pipe, 403 - Aqueous phase discharge pipe, 404 - Solvent / aqueous phase discharge pipe;

[0049] 1-Cylinder, 11-Feeding bin, 12-Support column, 13-Top cover, 14-Feed inlet, 15-Rotating shaft, 16-Agitator, 17-Agitator motor, 18-Observation window, 19-Frame, 2-Screen, 21-Spring, 22-Vibration motor, 23-Guide plate, 24-Roller, 25-Tilting plate, 26-Feeding motor, 27-Discharge pipe, 28-Discharge shaft, 29-Feeding plate, 3-Feeding motor, 31-Feeding pipe.

Detailed Implementation Methods

[0050] The following will be combined with the appendix Figure 1-4 The technical solution of this utility model is clearly and completely described in detail with specific embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0051] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0052] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 utility model based on the specific circumstances.

[0053] This utility model relates to a perfluoropentoxide epoxidation reaction system based on wastewater recycling, the reaction system structure comprising:

[0054] The reactant mixing assembly 100 includes a high-concentration sodium hypochlorite preparation system 101, a new acetonitrile solvent feed pipe 102, an acetonitrile solvent intermediate tank 103, a D2 feed pipe 104, a sodium hypochlorite metering pump 105, a solvent metering pump 106, a D2 metering pump 107, and a mixer 108; the high-concentration sodium hypochlorite preparation system 101 includes a solid sodium hypochlorite closed feeding device 109, a sodium hypochlorite preparation kettle 110, a sodium chloride centrifuge 111, a high-concentration sodium hypochlorite intermediate tank 112, and a sodium chloride packaging system 113.

[0055] The solid sodium hypochlorite closed feeding device 109 is connected to the inlet of the sodium hypochlorite preparation vessel 110, the outlet of the sodium hypochlorite preparation vessel 110 is connected to the sodium chloride centrifuge 111, and the light phase outlet of the sodium chloride centrifuge 111 is connected to the high-concentration sodium hypochlorite intermediate tank 112.

[0056] The high-concentration sodium hypochlorite intermediate tank 112 is connected to the sodium hypochlorite metering pump 105 via the high-concentration sodium hypochlorite feed pipe 114. The new acetonitrile solvent is connected to the acetonitrile solvent intermediate tank 103 via the new acetonitrile solvent feed pipe 102. The acetonitrile solvent intermediate tank 103 is connected to the solvent metering pump 106 via a pipe. D2 is connected to the D2 metering pump 107 via the D2 feed pipe 104. The sodium hypochlorite metering pump 105, the solvent metering pump 106, and the D2 metering pump 107 are respectively connected to the mixer 108 via pipes.

[0057] An epoxy reactor 200, the inlet of which is connected to the outlet of the mixer 108;

[0058] Separator 300 includes a first separator 301 and a second separator 302, which are connected in series. The inlet of the first separator 301 is connected to the reactant outlet of the epoxy reactor 200. The epoxide in the first separator 301 is output from the epoxy discharge pipe 401 through the heavy phase outlet. The solvent and aqueous phase material in the first separator 301 are connected to the bottom of the second separator 302 through the solvent / aqueous phase discharge pipe 404 through the light phase outlet. The solvent in the second separator 302 is output from the light phase outlet through the solvent circulation pipe 402 and sent to the acetonitrile solvent intermediate tank 103.

[0059] Wastewater containing sodium hypochlorite and sodium chloride in the second separator 302 is sent to the sodium hypochlorite preparation vessel 110 through the aqueous phase discharge pipe 403, and mixed with solid sodium hypochlorite added by the solid sodium hypochlorite closed feeding device 109 to prepare a sodium hypochlorite solution with a concentration of 15% to 20%.

[0060] In a preferred embodiment, the first separator 301 and the second separator 302 are both continuous closed centrifuges or stratified tanks.

[0061] In a preferred embodiment, the heavy phase outlet of the sodium chloride centrifuge 111 is connected to the sodium chloride packaging system 113.

[0062] In a preferred embodiment, the solid sodium hypochlorite closed feeding device 109 has the following structure: it includes a cylinder 1, a conical feeding hopper 11 at the bottom of the cylinder 1, a stirring mechanism at the upper part of the inner cavity of the cylinder 1, a frame 19 below the stirring mechanism, a screen 2 installed inside the frame 19, a spring 21 connecting the lower end of the frame 19 to a fixed block, and a vibration motor 22 installed on the frame 19. An inclined guide plate 23 is provided below the screen 2, and a speed adjustment mechanism is provided below the guide plate 23. The speed adjustment mechanism includes a roller 24, multiple flipping plates 25 on the side of the roller 24, one end of the roller 24 passing through the side wall of the feeding hopper 11 and connected to a feeding motor 26, a discharge pipe 27 installed at the side opening of the feeding hopper 11, a guiding mechanism inside the discharge pipe 27, and a feeding pipe 31 at the bottom opening of the discharge pipe 27. By coordinating the cylinder 1, feeding hopper 11, stirring mechanism, frame 19, screen 2, spring 21, vibrating motor 22, guide plate 23, speed adjustment mechanism (roller 24, tilting plate 25, feeding motor 26), discharge pipe 27, guiding mechanism and feeding pipe 31, the system achieves stirring and mixing, vibration screening, speed control and automatic feeding of solid sodium hypochlorite material. It solves the problems of easy material agglomeration leading to feeding blockage, lack of screening mechanism introducing impurities, uncontrollable feeding rate and need for manual feeding in the existing device, and improves feeding efficiency and material feeding accuracy.

[0063] In a preferred embodiment, the bottom of the cylinder 1 is provided with multiple support columns 12. The multiple support columns 12 are evenly distributed at the bottom of the cylinder 1, which can provide stable support for the entire device, balance the forces generated by the device during stirring, vibration and other operations, prevent the device from tilting or shaking violently, and ensure that each mechanism operates in a stable environment.

[0064] The top of the cylinder 1 is detachably connected to a top cover 13, and a feed inlet 14 is provided in the middle of the top cover 13. An openable sealing plate is installed inside the feed inlet 14. An observation window 18 is provided on the side of the cylinder 1. The top cover 13 is detachable, allowing operators to easily open the cylinder 1 to inspect, clean, or replace internal components such as the stirring mechanism and screen 2. The feed inlet 14 is the channel for adding materials. The sealing plate closes after material addition to prevent moisture from the outside air from entering the cylinder and causing the material to absorb moisture and clump, and also to prevent material dust from overflowing and polluting the environment. It also prevents external impurities from falling into the cylinder and contaminating the material. The observation window 18 is made of a transparent and wear-resistant material (such as tempered glass). Operators can use the observation window 18 to view the remaining amount of material in the cylinder, the working status of the stirring mechanism, and the screening status of the screen 2 in real time. This allows for timely monitoring of the internal operation of the device, facilitating timely replenishment when materials are insufficient, or rapid detection and handling of problems such as abnormal stirring or screen blockage.

[0065] In a preferred embodiment, the stirring mechanism includes a rotating shaft 15 with multiple stirring paddles 16 mounted on its outer side. The end of the rotating shaft 15 extends through to the outside of the cylinder 1 and is connected to a stirring motor 17. The stirring motor 17 provides the power source for the stirring action, driving the rotating shaft 15 to rotate synchronously. The multiple stirring paddles 16 on the outer side of the rotating shaft 15 rotate with it, enabling comprehensive stirring of the solid sodium hypochlorite material in the upper part of the cylinder 1's inner cavity. This breaks up large clumps formed due to moisture absorption, keeping the material loose and uniform, thus providing qualified material for subsequent screening steps.

[0066] In a preferred embodiment, the material guiding mechanism includes a discharge shaft 28, on which a plurality of feeding plates 29 are arranged at equal intervals, and one end of the discharge shaft 28 is connected to a feeding motor 3.

[0067] In a preferred embodiment, the feeding pipe 31 is equipped with a solenoid valve. The solenoid valve is connected to an external control system, and the operator can control the opening or closing of the solenoid valve through the control system according to the actual feeding needs, thereby controlling the on / off state of the feeding pipe 31, achieving precise control over the timing of feeding start and stop, and avoiding waste caused by the accidental discharge of materials when feeding is not required.

[0068] In another embodiment of this utility model, the operation steps of a perfluoropentane epoxidation reaction system based on wastewater recycling according to this utility model are as follows:

[0069] (1) Preparation of high-concentration sodium hypochlorite solution: The solid sodium hypochlorite closed feeding device 109 puts the required amount of solid sodium hypochlorite into the sodium hypochlorite preparation kettle 110 according to the process requirements, and mixes it with the wastewater containing sodium hypochlorite and sodium chloride sent into the second separator 302 through the aqueous phase discharge pipe 403 to prepare a 15% to 20% sodium hypochlorite solution.

[0070] The prepared sodium hypochlorite solution is fed into a sodium chloride centrifuge 111 to separate the precipitated sodium chloride. The mother liquor after centrifugation is stored in a high-concentration sodium hypochlorite intermediate tank 112.

[0071] (2) Mixing and reaction of reactants: Set the flow rates of sodium hypochlorite metering pump 105, solvent metering pump 106 and D2 metering pump 107 according to the proportion, and pump the high-concentration sodium hypochlorite solution, acetonitrile solvent and perfluoro-2-methyl-2-pentene (D2) into the mixer 108 for mixing and cooling, and control the temperature of the mixture to 10-20℃.

[0072] The mixed epoxy raw material liquid is fed into the epoxy reactor 200 through a conveying pipe to carry out the epoxidation reaction and generate perfluoroepoxypentane.

[0073] (3) Product separation and recovery: The epoxy liquid from the outlet of the epoxy reactor 200 enters the first separator 301 through the pipeline. After the epoxy is separated into layers, it flows from the heavy phase outlet of the first separator 301 into the next process through the epoxy discharge pipe 401. The aqueous phase and solvent from the light phase outlet flow into the second separator 302 through the solvent / aqueous phase discharge pipe 404. After the layer separation, the aqueous phase containing sodium chloride and sodium hypochlorite flows out from the heavy phase outlet of the second separator 302 and flows into the sodium hypochlorite preparation kettle 110 through the aqueous phase discharge pipe 403. The acetonitrile solvent flows from the light phase outlet into the acetonitrile solvent intermediate tank 103 through the solvent circulation pipe 402 for recycling. The lost solvent is replenished by the new acetonitrile solvent inlet pipe 102.

[0074] The feeding process of the solid sodium hypochlorite closed feeding device 109 in step (1) is as follows:

[0075] Feeding stage: First, open the sealing plate inside the feed inlet 14 on the top cover 13, and feed the solid sodium hypochlorite material into the cylinder 1 through the feed inlet 14. The material falls into the upper area of ​​the inner cavity of the cylinder 1 under the action of gravity. After the material is added to the preset amount, close the sealing plate inside the feed inlet 14 to prevent external moisture and impurities from entering the cylinder, and at the same time avoid material dust from overflowing.

[0076] Material mixing stage: Start the stirring motor 17. The stirring motor 17 drives the rotating shaft 15 to rotate through the transmission structure. Multiple stirring paddles 16 on the outside of the rotating shaft 15 rotate synchronously with the rotating shaft 15. During the rotation, the stirring paddles 16 come into full contact with the solid sodium hypochlorite material in the cylinder, breaking up the clumps formed by moisture absorption in the material, so that the material as a whole remains loose and uniform, laying the foundation for subsequent screening steps.

[0077] Material screening stage: The loose material after stirring falls naturally onto the screen 2 inside the frame 19 below the stirring mechanism under the action of gravity; the vibration motor 22 is started, and the vibration force generated by the vibration motor 22 is transmitted to the frame 19. The frame 19 reciprocates under the elastic support of the bottom spring 21, which in turn drives the screen 2 to vibrate synchronously; the screen 2 intercepts the lumps and impurities in the material that have not been completely broken up on the surface of the screen 2 through vibration (which can be cleaned later by opening the top cover 13), and qualified materials that meet the particle size requirements fall through the mesh of the screen 2, thus completing the material screening and purification.

[0078] Material guiding stage: Qualified materials after being screened by screen 2 fall onto the inclined guide plate 23 below screen 2; with the help of the inclined angle of guide plate 23, the material slides smoothly along the surface of guide plate 23 under the action of gravity, slides out from the lower end of guide plate 23, and is accurately guided to the speed adjustment mechanism below guide plate 23, avoiding the material from falling directly onto the speed adjustment mechanism and causing accumulation.

[0079] Feeding rate adjustment stage: Start the feeding motor 26. The feeding motor 26 drives the roller shaft 24 to rotate at the corresponding speed according to the preset feeding rate requirement. Multiple flip plates 25 on the side of the roller shaft 24 rotate synchronously with the roller shaft 24. The material sliding down from the guide plate 23 enters the gap formed between the roller shaft 24 and the flip plates 25. The flip plates 25 gradually convey the material downward during the rotation process. By adjusting the speed of the feeding motor 26 (the faster the speed, the more material is conveyed per unit time, and vice versa), the feeding rate of the material can be precisely controlled. The adjusted material falls into the feeding hopper 11 and gathers at the opening of the discharge pipe 27 on the side of the feeding hopper 11.

[0080] Material discharge and conveying stage: After the material in the discharge hopper 11 enters the discharge pipe 27 through the opening, the feeding motor 3 is started. The feeding motor 3 drives the discharge shaft 28 to rotate, and the multiple feeding plates 29 on the discharge shaft 28 rotate synchronously with the discharge shaft 28. During the rotation, the feeding plates 29 push the material in the discharge pipe 27 to move along the pipe body direction, and smoothly and evenly convey the material to the bottom opening of the discharge pipe 27, so as to avoid the material from staying and accumulating in the discharge pipe 27 and causing blockage.

[0081] Final feeding stage: According to the feeding requirements of the target system, the external control system sends an opening signal to the solenoid valve on the feed pipe 31. The solenoid valve opens, and the material at the bottom opening of the discharge pipe 27 enters the feed pipe 31 and is transported to the target location (such as a water treatment reaction tank, disinfection equipment, etc.) through the feed pipe 31, completing the automatic feeding. When the feeding amount reaches the preset value or no further feeding is needed, the control system sends a closing signal, the solenoid valve closes, the feed pipe 31 stops discharging, and the feeding process ends. The operator can check the remaining amount of material in the cylinder through the observation window 18 on the side of the cylinder 1. If the material is insufficient, the above steps can be repeated for the next round of feeding.

[0082] In summary, this utility model has the following advantages:

[0083] (1) Clean and environmentally friendly process: The process of this utility model uses wastewater to prepare sodium hypochlorite solution, reducing high-salt wastewater by 4 to 6 tons per ton of product, and does not generate wastewater. The process is clean and environmentally friendly.

[0084] (2) Energy consumption is greatly reduced: This utility model directly uses the saline wastewater after the reaction to prepare sodium hypochlorite solution, avoiding the use of a high-salt water concentration and crystallization system, saving 0.5 to 2.5 tons of steam per ton of product, and greatly reducing energy consumption;

[0085] (3) The utilization rate of sodium hypochlorite raw materials is increased by 50%: The wastewater from this process is reused to prepare sodium hypochlorite solution. More than 50% of the unreacted sodium hypochlorite in the wastewater is reused, and the utilization rate of sodium hypochlorite is greatly improved.

[0086] (4) Equipment investment saved by 30%: This utility model uses the wastewater after the reaction to prepare a 15% to 20% sodium hypochlorite solution. The sodium chloride generated by the reaction is directly precipitated by the common ion effect. The waste salt can be obtained by centrifugation, avoiding the use of a multi-effect evaporation crystallization system, which greatly simplifies the process and saves a lot of investment and operating costs.

[0087] (5) More stable reaction conditions and higher conversion rate: This utility model uses solid sodium hypochlorite and wastewater to prepare a high-concentration sodium hypochlorite solution. The concentration can be increased to 15% to 20% according to process requirements, and it can be used immediately after preparation. This not only increases the concentration of sodium hypochlorite solution, but also avoids the problem of effective chlorine loss during storage, thereby improving the stability and conversion rate of product quality.

[0088] (6) The closed feeding device for solid sodium hypochlorite has a reasonable structural design and can realize the stirring, mixing, vibration screening, rate control and automatic feeding of solid sodium hypochlorite material. It solves the problems of easy material agglomeration leading to material blockage, lack of screening mechanism introducing impurities, uncontrollable feeding rate and need for manual feeding in the existing device, and improves feeding efficiency and material feeding accuracy.

[0089] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A perfluoropentane epoxidation reaction system based on wastewater recycling, characterized in that: The reaction system structure includes: The reactant mixing assembly (100) includes a high-concentration sodium hypochlorite preparation system (101), a new acetonitrile solvent feed pipe (102), an acetonitrile solvent intermediate tank (103), a D2 feed pipe (104), a sodium hypochlorite metering pump (105), a solvent metering pump (106), a D2 metering pump (107), and a mixer (108); the high-concentration sodium hypochlorite preparation system (101) includes a solid sodium hypochlorite closed feeding device (109), a sodium hypochlorite preparation kettle (110), a sodium chloride centrifuge (111), and a high-concentration sodium hypochlorite intermediate tank (112); The solid sodium hypochlorite closed feeding device (109) is connected to the inlet of the sodium hypochlorite preparation vessel (110), the outlet of the sodium hypochlorite preparation vessel (110) is connected to the sodium chloride centrifuge (111), and the light phase outlet of the sodium chloride centrifuge (111) is connected to the high-concentration sodium hypochlorite intermediate tank (112). The high-concentration sodium hypochlorite intermediate tank (112) is connected to the sodium hypochlorite metering pump (105) through the high-concentration sodium hypochlorite feed pipe (114). The new acetonitrile solvent is connected to the acetonitrile solvent intermediate tank (103) through the new acetonitrile solvent feed pipe (102). The acetonitrile solvent intermediate tank (103) is connected to the solvent metering pump (106) through a pipe. D2 is connected to the D2 metering pump (107) through the D2 feed pipe (104). The sodium hypochlorite metering pump (105), the solvent metering pump (106), and the D2 metering pump (107) are respectively connected to the mixer (108) through pipes. An epoxy reactor (200) is provided, the inlet of which is connected to the outlet of the mixer (108); The separator (300) includes a first separator (301) and a second separator (302), which are connected in series. The inlet of the first separator (301) is connected to the reactant outlet of the epoxy reactor (200). The epoxide in the first separator (301) is output from the epoxy discharge pipe (401) through the heavy phase outlet, and the solvent and aqueous phase materials in the first separator (301) are output from the light phase outlet. The outlet is connected to the bottom of the second separator (302) through the solvent / aqueous phase outlet pipe (404); the solvent in the second separator (302) is output from the light phase outlet through the solvent circulation pipe (402) and sent to the acetonitrile solvent intermediate tank (103); the wastewater containing sodium hypochlorite and sodium chloride in the second separator (302) is sent to the sodium hypochlorite preparation kettle (110) through the aqueous phase outlet pipe (403) and mixed with the solid sodium hypochlorite fed by the solid sodium hypochlorite closed feeding device (109).

2. The perfluoroepoxide epoxidation reaction system based on wastewater recycling according to claim 1, characterized in that: Both the first separator (301) and the second separator (302) are continuous closed centrifuges or stratified tanks.

3. The perfluoroepoxypentane epoxidation reaction system based on wastewater recycling according to claim 1, characterized in that: The heavy phase outlet of the sodium chloride centrifuge (111) is connected to the sodium chloride packaging system (113).

4. The perfluoroepoxide epoxidation reaction system based on wastewater recycling according to claim 1, characterized in that: The solid sodium hypochlorite closed feeding device (109) has the following structure: it includes a cylinder (1), a conical feeding hopper (11) at the bottom of the cylinder (1), a stirring mechanism at the upper part of the inner cavity of the cylinder (1), a frame (19) below the stirring mechanism, a screen (2) installed inside the frame (19), the lower end of the frame (19) is connected to a fixed block by a spring (21), and a vibration motor (22) is installed on the frame (19). An inclined plate is provided below the screen (2). An inclined guide plate (23) is provided below the guide plate (23). The speed adjustment mechanism includes a roller (24). Multiple flip plates (25) are provided on the side of the roller (24). One end of the roller (24) passes through the side wall of the feeding bin (11) and is connected to a feeding motor (26). A discharge pipe (27) is installed at the side opening of the feeding bin (11). A guide mechanism is provided inside the discharge pipe (27). A feeding pipe (31) is provided at the bottom opening of the discharge pipe (27).

5. The perfluoroepoxide epoxidation reaction system based on wastewater recycling according to claim 4, characterized in that: The bottom of the cylinder (1) is provided with multiple support columns (12); the top of the cylinder (1) is detachably connected with a top cover (13), and a feed inlet (14) is opened in the middle of the top cover (13), and an openable sealing plate is provided inside the feed inlet (14); an observation window (18) is provided on the side of the cylinder (1).

6. The perfluoroepoxide epoxidation reaction system based on wastewater recycling according to claim 4, characterized in that: The stirring mechanism includes a rotating shaft (15), and multiple stirring paddles (16) are provided on the outside of the rotating shaft (15). The end of the rotating shaft (15) extends through the outside of the cylinder (1) and is connected to the stirring motor (17) for transmission.

7. The perfluoroepoxide epoxidation reaction system based on wastewater recycling according to claim 4, characterized in that: The material guiding mechanism includes a discharge shaft (28), on which multiple feeding plates (29) are arranged at equal intervals, and one end of the discharge shaft (28) is connected to a feeding motor (3).

8. The perfluoropentane epoxidation reaction system based on wastewater recycling according to claim 4, characterized in that: A solenoid valve is installed on the feed pipe (31).

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