Oxidation preparation device and method of catalyst carrier for polyimide synthesis

Abstract

The invention relates to the technical field of reactors for chemical preparation, in particular to an oxidation preparation device and method of a catalyst carrier for polyimide synthesis, graphite or potassium permanganate and the like are fed from a feed inlet, the fed material falls down along a feed pipe, a feed channel and a vertical blanking channel in sequence, and is pushed along a transverse blanking channel, and the graphite or potassium permanganate and the like are fed into the reactor. Meanwhile, the main shaft is controlled to axially rotate to drive the stirring blades to mix and stir, and the annular table drives the material scattering roller to axially rotate, so that pushed materials in the transverse material falling channel sequentially fall into the strip-shaped groove, scatter the fed materials into the kettle when rotating away from the side connecting blade on one side along with the strip-shaped groove, and scatter the fed materials into the kettle when rotating to the bottom end of the side connecting blade on the other side along with the strip-shaped groove. And the scraping plate elastically extends downwards and abuts against the outer side of the material scattering roller, so that liquid in the kettle is prevented from entering the transverse blanking channel along the material scattering roller, more efficient mixing and uniform oxidation reaction are facilitated, and the difficulty of temperature and feeding rate control and deep oxidation control is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of reactors for chemical preparation, and particularly to an oxidation preparation device and method for a catalyst support for polyimide synthesis. Background Art

[0002] Polyimide monomer 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) is a white crystalline powder mainly used in the production of polyimides. Its preparation method usually adopts the condensation reaction of chlorophthalic anhydride, lye, additives and a catalyst. Among them, the catalyst mostly uses metal-loaded graphene that can be reused repeatedly. One of the key factors determining its reuse quality is the catalyst support material, such as the graphene support material. For the preparation of the graphene support material, such as the nitrogen-doped graphene, Pd-loaded nitrogen-doped graphene catalyst and its preparation method and application disclosed in Chinese Patent Document CN104998631A, it is generally prepared through processes such as oxidation reaction, drying, calcination, and screening. Among them, for the initial oxidation preparation process, the existing method generally adopts the Hummers method and its improved methods. Specifically, under the condition of a cold bath, graphite is slowly added to concentrated sulfuric acid or a mixed acid solution for low-temperature pre-oxidation, and then a strong oxidant such as potassium permanganate (KMnO4) is slowly added in batches to avoid violent heat release. Then, the temperature is raised and continuous stirring is carried out for sufficient deep oxidation reaction. Finally, deionized water, hydrogen peroxide, etc. are added to terminate the reaction, so as to obtain a graphene oxide dispersion. In actual preparation, especially when using a large-scale reaction kettle for oxidation preparation production, whether adding graphite raw materials or strong oxidants such as potassium permanganate, the temperature and feeding rate need to be strictly controlled. It is often necessary to design a powder conveying and dispersing system, and cooperate with multiple feeding ports or feeding nozzles to feed towards the liquid surface in the kettle, and deploy multi-point temperature monitoring in the kettle, and adjust the feeding rate in real time according to the temperature change to avoid local overheating, triggering side reactions (such as excessive oxidation of graphite, structural damage) or even the risk of splashing or explosion. It is also necessary to deploy a multi-point bypass sampling mechanism in the kettle to analyze the oxidation degree of graphite in real time to avoid uneven distribution of the oxidant caused by insufficient stirring efficiency, thereby affecting the quality of the oxidation consistency of the graphite layer. Therefore, further optimization and improvement are required. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide an oxidation preparation device and method for a catalyst support for polyimide synthesis, so as to solve the problems that when the existing catalyst support, especially when using a large-scale reaction kettle for oxidation preparation, it is difficult to control the temperature and feeding rate in the kettle and the deep oxidation control, and the process operation is inconvenient.

[0004] Based on the above purpose, the present invention provides an oxidation preparation device for a catalyst support for polyimide synthesis, including a reaction kettle, and a stirring mechanism is arranged in the reaction kettle: The stirring mechanism includes a main shaft. A stirring blade is horizontally connected to the side end of the main shaft. A shaft sleeve is fixedly arranged at the top end inside the reaction kettle, and the shaft sleeve is sleeved outside the main shaft. A feed pipe is externally connected to the side end of the shaft sleeve. A vertical blanking channel is opened inside the main shaft, and a horizontal blanking channel is opened at the bottom end inside the stirring blade. The feed falls sequentially along the feed pipe and the vertical blanking channel, and is pushed along the horizontal blanking channel. At the bottom end outside the stirring blade, a material spreading roller is arranged along its length direction. A plurality of strip-shaped grooves are spacedly arranged on the outer circumference of the material spreading roller. The length direction of the strip-shaped grooves is parallel to the length direction of the material spreading roller. Side connecting blades are fixedly connected to both sides at the bottom end of the stirring blade, and the bottom ends of the side connecting blades are attached to the material spreading roller. A scraping plate is arranged inside at least one side connecting blade. An annular platform is arranged along the circumference inside the reaction kettle. The annular platform is in driving connection with the end of the material spreading roller away from the main shaft. When the main shaft rotates axially, the material spreading roller is driven to rotate axially through the annular platform, so that the material pushed in the horizontal blanking channel falls into the strip-shaped grooves in sequence. When the strip-shaped grooves rotate away from one side connecting blade, the feed is scattered into the kettle. The scraping plate inside the other side connecting blade elastically extends downward and abuts against the outer side of the material spreading roller.

[0005] Preferably, a spiral coiled pipe is arranged inside the reaction kettle. Liquid receiving pipes are respectively connected to both ends of the spiral coiled pipe, and the liquid receiving pipes vertically penetrate out of the reaction kettle.

[0006] Preferably, baffles are fixedly connected to the inner side of the spiral coiled pipe. A plurality of baffles are spacedly arranged along the inner circumference of the spiral coiled pipe. The annular platform is fixedly connected to the inner side of the baffles.

[0007] Preferably, a plurality of stirring blades are spacedly arranged along the outer circumference of the main shaft, and are arranged in multiple layers at intervals along the up and down directions of the main shaft.

[0008] Preferably, end plates are arranged at the ends of the material spreading roller. The end plates are fixedly connected to the bottom ends of the side connecting blades. A roller shaft is fixedly connected to the end of the material spreading roller. One end of the roller shaft penetrates out of the end plate and is connected with a gear. A toothed structure engaged with the gear is arranged on the annular platform.

[0009] Preferably, one end of the roller shaft penetrates into the main shaft and is connected with a cam. A thin shaft is arranged in parallel inside the vertical blanking channel. The bottom end of the thin shaft penetrates out of the vertical blanking channel. A sealing bellows is connected between the bottom end of the thin shaft located inside the vertical blanking channel and the vertical blanking channel. When the material spreading roller rotates axially, the cam is driven to rotate synchronously, which is used to push the thin shaft to vibrate up and down.

[0010] Preferably, a crushing hammer is connected to the top end of the thin shaft located inside the vertical blanking channel.

[0011] Preferably, the scraping plate is symmetrically arranged inside the side connection leaves on both sides. A walking wheel is rotatably connected to the bottom end of the horizontal blanking channel. The bottom end of the walking wheel is attached to and moves along the outer end of the material spreading roller. A wire winding wheel is connected to one side of the walking wheel. A pulling rope is wound around the wire winding wheel. One end of the pulling rope passes into the side connection leaf and is connected to the scraping plate. When the material spreading roller rotates axially, it drives the walking wheel to rotate synchronously, so that the pulling rope on one side is tensioned. The tensioned pulling rope pulls the scraping plate, so that the scraping plate on the same side cannot elastically extend out.

[0012] The present invention also provides an oxidation preparation method for a catalyst carrier used in polyimide synthesis, comprising the following steps: During the oxidation preparation, concentrated sulfuric acid or a mixed acid solution is input into the reaction kettle through the feeding port, and then graphite material is input through the feeding port. The feed sequentially falls along the feed pipe, the feed channel, and the vertical blanking channel, and is pushed inside the horizontal blanking channel. At the same time, the main shaft is controlled to rotate axially, driving the stirring blades to mix and stir. During the rotation of the stirring blades, the material spreading roller is driven to rotate axially through the annular platform, so that the pusher inside the horizontal blanking channel sequentially falls into the strip-shaped grooves. When the strip-shaped grooves rotate away from the side connection leaf on one side, the feed is scattered into the kettle. When the strip-shaped grooves rotate into the bottom end of the side connection leaf on the other side, the scraping plate elastically extends downward and abuts against the outer side of the material spreading roller, preventing the acid solution in the kettle from entering the horizontal blanking channel along the material spreading roller; After low-temperature pre-oxidation, strong oxidants such as potassium permanganate are slowly added in batches through the feeding port, and the potassium permanganate powder is scattered into the kettle as the strip-shaped grooves rotate; After the material scattering is completed, the temperature inside the kettle is controlled to rise and continuous stirring is carried out for a sufficient deep oxidation reaction. Then, liquid materials such as deionized water and hydrogen peroxide are introduced through the feeding port to terminate the reaction, removing the excessive potassium permanganate to obtain a graphene oxide dispersion. The dispersion is exported from the drain port at the bottom end of the reaction kettle, and then a graphene carrier material is prepared through subsequent processes such as washing, drying, roasting, and screening.

[0013] Advantages of the present invention: Sulfuric acid or a mixed acid solution is introduced into the reaction kettle through the feeding port, and then graphite material is introduced through the feed port. The feed sequentially falls along the feed pipe, the feed channel, and the vertical falling channel, and is pushed along the horizontal falling channel. At the same time, the main shaft is controlled to rotate axially to drive the mixing and stirring of the stirring blades. During the rotation of the stirring blades, the annular table drives the axial rotation of the material spreading roller, so that the material pushed in the horizontal falling channel sequentially falls into the strip-shaped grooves. When the strip-shaped grooves rotate away from the side connecting blades on one side, the feed is scattered into the kettle. When the strip-shaped grooves rotate into the bottom end of the side connecting blades on the other side, the scraper elastically extends downward and abuts against the outer side of the material spreading roller to prevent the acid solution in the kettle from entering the horizontal falling channel along the material spreading roller. After low-temperature pre-oxidation, strong oxidants such as potassium permanganate are slowly added in batches through the feed port. The potassium permanganate powder is then scattered into the kettle as the strip-shaped grooves rotate. After the material spreading is completed, the temperature in the kettle is controlled to rise and continuous stirring is carried out for sufficient deep oxidation reaction. Then, liquid materials such as deionized water and hydrogen peroxide are introduced through the feed port to terminate the reaction, and a graphene oxide dispersion liquid is obtained. The dispersion liquid is discharged from the drain port at the bottom of the reaction kettle and then processed through subsequent processes such as washing, drying, roasting, and screening to obtain a graphene carrier material. Among them, powders such as graphite or potassium permanganate are scattered into the liquid surface in the kettle as the stirring blades rotate, which is beneficial for more efficient mixing and uniform oxidation reaction, and reduces the difficulty of temperature and feeding rate control as well as deep oxidation control. Description of the Drawings

[0014] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only those of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0015] Figure 1 It is a schematic diagram of the overall internal structure of the reaction kettle of the present invention; Figure 2 For the present invention Figure 1 The enlarged schematic diagram at A in; Figure 3 For the present invention Figure 1 The enlarged schematic diagram at B in; Figure 4 It is a top view structural schematic diagram of the spiral coil pipe and the baffle of the present invention; Figure 5 It is a side view structural schematic diagram of the stirring blade of the present invention; Figure 6 It is a side view structural schematic diagram of the horizontal falling channel and the material spreading roller of the present invention; Figure 7 It is a side view structural schematic diagram when the material spreading roller rotates counterclockwise of the present invention; Figure 8Schematic diagram of the structure when the stirring blade of the present invention is designed in an inclined blade paddle structure; Figure 9 Schematic diagram of the structure of the walking wheel and the pulling rope of the present invention; Figure 10 Schematic diagram of the overall internal structure of the reaction kettle with a cam and a thin shaft in the present invention; Figure 11 For the present invention Figure 10 Enlarged schematic diagram at position C.

[0016] Marked in the figure as: 1. Reaction kettle; 100. Feeding port; 101. Drainage port; 2. Jacket; 3. Main shaft; 31. Vertical blanking channel; 4. Stirring blade; 41. Horizontal blanking channel; 5. Sleeve; 51. Feed channel; 6. Feed pipe; 61. Feed inlet; 7. Spreading roller; 71. Strip-shaped groove; 72. Roller shaft; 8. Side connecting blade; 9. Scraper; 10. Annular platform; 11. Spiral coil; 12. Liquid receiving pipe; 13. Baffle; 14. Connecting plate; 15. End plate; 16. Gear; 17. Cam; 18. Thin shaft; 19. Sealing bellows; 20. Walking wheel; 21. Pulling rope. Detailed implementation manners

[0017] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with specific embodiments.

[0018] It should be noted that unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meanings understood by those with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not represent any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. The terms such as "connected" or "linked" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left" and "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0019] Such as Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7As shown in the figure, an oxidation preparation device for a catalyst carrier used in polyimide synthesis includes a reaction kettle 1. A stirring mechanism is provided inside the reaction kettle 1. The stirring mechanism includes a main shaft 3. A stirring blade 4 is horizontally connected to the side end of the main shaft 3. A shaft sleeve 5 is fixedly provided at the top end inside the reaction kettle 1. The shaft sleeve 5 is sleeved outside the main shaft 3. A feed pipe 6 is externally connected to the side end of the shaft sleeve 5. A vertical blanking channel 31 is opened inside the main shaft 3. A horizontal blanking channel 41 is opened at the bottom end inside the stirring blade 4. The feed sequentially falls along the feed pipe 6 and the vertical blanking channel 31, and is pushed inside the horizontal blanking channel 41. A material spreading roller 7 is provided along the length direction at the bottom end outside the stirring blade 4. A plurality of strip-shaped grooves 71 are arranged at intervals on the outer circumference of the material spreading roller 7. The length direction of the strip-shaped grooves 71 is parallel to the length direction of the material spreading roller 7. Side connecting blades 8 are fixedly connected to both sides of the bottom end of the stirring blade 4. The bottom end of the side connecting blade 8 is attached to the material spreading roller 7. A scraping plate 9 is provided inside at least one of the side connecting blades 8. An annular platform 10 is arranged along the circumferential direction inside the reaction kettle 1. The annular platform 10 is drivingly connected to one end of the material spreading roller 7 away from the main shaft 3. When the main shaft 3 rotates axially, the material spreading roller 7 is driven to rotate axially through the annular platform 10, so that the material pushed inside the horizontal blanking channel 41 sequentially falls into the strip-shaped grooves 71. When the strip-shaped grooves 71 rotate away from one side connecting blade 8, the feed is scattered into the kettle. The scraping plate 9 inside the other side connecting blade 8 elastically extends downward and abuts against the outer side of the material spreading roller 7.

[0020] Based on the existing conventional oxidation preparation process of catalyst carriers for polyimide synthesis such as graphene carrier materials and the structural principle of oxidation reactors, the present invention includes a reaction kettle 1. A stirring mechanism is provided inside the reaction kettle 1. A jacket 2 is provided on the outer circumference of the side end of the reaction kettle 1. A heat transfer medium (such as ethylene glycol - aqueous solution or heat transfer oil, etc.) is circulated inside the jacket 2 for heat exchange with the inside of the reaction kettle 1. The stirring mechanism includes a main shaft 3 vertically extending into the reaction kettle 1. A stirring blade 4 is horizontally connected to the side end of the main shaft 3. Specifically, the stirring mechanism further includes a power device such as a driving motor fixed to the top end of the reaction kettle 1 for driving the main shaft 3 to rotate axially. The reaction kettle 1 is usually designed in a cylindrical shape. A feeding port 100 is also provided at the top end of the reaction kettle 1. The main shaft 3 extends into the reaction kettle 1 along the central axis direction of the reaction kettle 1. A shaft sleeve 5 is fixedly provided at the top end inside the reaction kettle 1. The shaft sleeve 5 is sleeved outside the main shaft 3 but does not affect the rotation of the main shaft 3. A feed pipe 6 is fixedly externally connected to the side end of the shaft sleeve 5. As Figure 1As shown, the feed pipes 6 can be symmetrically arranged on both sides of the bushing 5. The feed pipes 6 are divided into an inclined section close to the bushing 5 and a vertical pipe section connected to the top of the inclined section. The vertical pipe section penetrates upward through the reaction kettle 1 and is provided with a feed port 61. A feed channel 51 is arranged in the bushing 5. The feed channel 51 is equivalent to the extended design of the feed pipe 6 in the bushing 5 and is used to communicate with the feed pipe 6. A vertical blanking channel 31 is opened in the main shaft 3 along its length direction. The top end of the vertical blanking channel 31 is connected to the bottom end of the feed channel 51. A horizontal blanking channel 41 is opened at the inner bottom end of the stirring blade 4 along its length direction. The bottom end of the vertical blanking channel 31 is connected to the horizontal blanking channel 41; Among them, a material spreading roller 7 is arranged at the outer bottom end of the stirring blade 4 along its length direction. A plurality of strip-shaped grooves 71 are arranged at intervals on the outer circumference of the material spreading roller 7. The length direction of the strip-shaped grooves 71 is parallel to the length direction of the material spreading roller 7. Side connecting blades 8 are fixedly connected to both sides of the bottom end of the stirring blade 4. The side connecting blades 8 can be integrally formed with the stirring blade 4, such as Figure 6 As shown, the bottom end of the side connecting blade 8 is attached to the material spreading roller 7. The bottom end of the horizontal blanking channel 41 is open and faces the material spreading roller 7. A scraping plate 9 is arranged in at least one side connecting blade 8. An annular platform 10 is arranged along the circumferential direction in the reaction kettle 1. The annular platform 10 is drivingly connected to one end of the material spreading roller 7 away from the main shaft 3. Therefore, during use, that is, when preparing graphene carrier oxidation, concentrated sulfuric acid or mixed acid solution can be put into the reaction kettle 1 through the feeding port 100, and then graphite material is put in through the feed port 61. Among them, the graphite material can be directly put in powder form or can be introduced into the feed port 61 in the form of a mixture of graphite powder and air flow through a pneumatic conveying system. The feed sequentially falls along the feed pipe 6, the feed channel 51, and the vertical blanking channel 31, and is pushed in the horizontal blanking channel 41. At this time, the cold bath temperature condition is controlled in the reaction kettle 1, and at the same time, the axial rotation of the main shaft 3 is controlled to drive the stirring blade 4 to mix and stir. When the stirring blade 4 rotates synchronously with the main shaft 3, the axial rotation of the material spreading roller 7 is driven through the annular platform 10, so that the material pushed in the horizontal blanking channel 41 sequentially falls into the strip-shaped grooves 71, such as Figure 6 、 Figure 7As shown, the material spreading roller 7 rotates counterclockwise. When the strip-shaped groove 71 rotates away from the side connection leaf 8 on one side, the feed is spread into the kettle. When the strip-shaped groove 71 rotates into the bottom end of the side connection leaf 8 on the other side, the scraper 9 elastically extends downward and abuts against the outer side of the material spreading roller 7 to prevent the acid liquid in the kettle from entering the horizontal feed channel 41 along the material spreading roller 7. After low-temperature pre-oxidation, when strong oxidants such as potassium permanganate (KMnO4) are added in batches slowly, the potassium permanganate powder can also be put into the feed port 61, or the mixed gas is introduced into the feed port 61 by means of pneumatic conveying and then spread into the kettle as the strip-shaped groove 71 rotates. Since the pressure of the liquid mass in the kettle is blocked by the scraper 9, a very high feed air flow is not required. After the material spreading is completed, the temperature in the kettle is controlled to rise and continuous stirring is carried out for a sufficient deep oxidation reaction. At this time, the feeding stops, and the liquid mass in the kettle will not flow back into the horizontal feed channel 41. Finally, liquid materials such as deionized water and hydrogen peroxide can be introduced into the feed port 61 to terminate the reaction and remove the excessive potassium permanganate. And the liquid materials are spread out by the material spreading roller 7, which is beneficial to flushing the residual powder in the channel, so as to obtain graphene oxide dispersion liquid. The dispersion liquid is then led out from the drain port 101 at the bottom end of the reaction kettle 1 and then prepared into graphene carrier materials through subsequent processes such as washing, drying, roasting, and screening. Among them, powders such as graphite or potassium permanganate are scattered into the liquid surface in the kettle as the stirring blade 4 rotates. Compared with the traditional feeding from the feeding port or feeding nozzle at the top of the kettle towards the liquid surface in the kettle, firstly, the material spreading rotates and scatters synchronously with the stirring blade 4 and scatters along the length direction of the bottom end of the stirring blade 4, further improving the dispersion uniformity of the material spreading. On the other hand, the material spreading is located below the liquid surface and close to the movement of the stirring blade 4, which is beneficial to the further rapid diffusion of the material spreading below the liquid surface in the kettle, thus avoiding local overheating, side reactions (such as excessive oxidation of graphite and structural damage) or even the risks of splashing or explosion that are likely to occur when the feeding stays in the local space on the liquid surface, facilitating more efficient mixing and uniform oxidation reaction, and the mixed air flow introduced into the feed port 61 also helps to disperse the microbubbles of the feed, thus further facilitating efficient mixing and oxidation, thereby reducing the difficulty of temperature and feeding rate control and deep oxidation control.

[0021] Among them, optionally, the oxidation preparation device of the catalyst carrier of the present invention can be designed with a single reaction kettle 1, i.e., a single-kettle design. The inner wall of the kettle is lined with materials that are resistant to high temperature, acid corrosion, and oxidation corrosion. It can also be designed with multiple reaction kettles 1 in series, i.e., a multi-kettle series design. According to adding graphite material into concentrated sulfuric acid or mixed acid liquid, carrying out low-temperature mixing and stirring and pre-oxidation; then adding strong oxidants such as potassium permanganate in batches slowly; then raising the temperature and continuously stirring for a sufficient deep oxidation reaction and other multiple stages, multiple reaction kettles 1 are correspondingly designed, and the circulating medium in the jacket 2 is adaptively selected, such as ethylene glycol - aqueous solution (low-temperature section) or heat-conducting oil (high-temperature section). The liquid infusion between multiple kettles can be completed by connecting in series through the drain port 101 and the feeding port 100, so as to reduce the single-kettle load.

[0022] Among them, the scraper 9 can adopt the existing conventional design such as an elastic telescopic cylinder, but only replace the cylindrical structure in the elastic telescopic cylinder with a plate-like structure. For example, Figure 6 , Figure 7 As shown, the scraper 9 can include a hollow fixed plate fixed inside the side connecting blade 8. An active plate is elastically inserted inside the hollow fixed plate so that the active plate elastically extends downward. A scraping strip is connected to the bottom end of the active plate along its length direction. The scraping strip is designed to be of the same length as the strip-shaped groove 71 and is used to abut against the strip-shaped groove 71 to scrape the liquid mass in the kettle. The scraping strip can be made of existing materials such as polytetrafluoroethylene (PTFE) or fluororubber (FKM) that are resistant to strong acids and high temperatures. Relying on the elastic extension of the active plate, even if the scraping strip is worn, it will not affect the use of the scraping strip in a short time. More preferably, the side connecting blade 8 and the material spreading roller 7 can be designed to be detachably connected to the stirring blade 4. When maintaining after long-term use, the kettle top cover can be opened and the new side connecting blade 8 and the material spreading roller 7 can be disassembled and replaced. When performing short-term maintenance, the cleaning liquid can be directly introduced through the feed port 61, and the cleaning liquid is spread out through the material spreading roller 7 to achieve convenient flushing and cleaning of the residual impurities in the channel. In addition, the inclination angle of the scraper 9 can be optimized for the material spreading roller 7 and the strip-shaped groove 71 to ensure efficient scraping and liquid blocking.

[0023] In an embodiment of the present invention, optionally, a spiral coiled pipe 11 can also be provided inside the reaction kettle 1. As Figure 1 , Figure 4 shown, the spiral coiled pipe 11 is spirally wound around the position close to the inner wall of the reaction kettle 1. Both ends of the spiral coiled pipe 11 (i.e., the head end at the top and the tail end at the bottom) are respectively connected with a liquid receiving pipe 12. The liquid receiving pipe 12 vertically penetrates out of the reaction kettle 1 along the inner side of the spiral coiled pipe 11 and is used to circulate a cooling medium into the spiral coiled pipe 11 to enhance the local heat dissipation capacity and prevent thermal runaway caused by heat release during the oxidation reaction, etc.

[0024] In an embodiment of the present invention, optionally, a baffle 13 is fixedly connected to the inner side of the spiral coiled pipe 11. As Figure 1 , Figure 4 shown, the baffle 13 is vertically arranged and is provided with a plurality of them at intervals along the inner circumference of the spiral coiled pipe 11 and is used to improve the stirring effect. Among them, part of the baffle 13 is fixedly connected to the inner side of the liquid receiving pipe 12, part of the outer side of the baffle 13 is fixedly connected with a connecting plate 14, and is fixedly connected to the inner wall of the reaction kettle 1 through the connecting plate 14. The annular platform 10 can be fixedly connected to the inner side of the baffle 13.

[0025] In an embodiment of the present invention, optionally, a plurality of stirring blades 4 can be arranged at intervals along the outer circumference of the main shaft 3 and are arranged in multiple layers at intervals along the main shaft 3. That is, the stirring blade 4 can adopt the existing conventional structural designs such as paddle type and turbine type. As Figure 1 shown, the stirring blade 4 is a double-layer straight blade paddle type design, that is, the width direction of the stirring blade 4 is parallel to the axial direction of the main shaft 3. As Figure 8As shown, the stirring blade 4 is designed as an inclined blade paddle, which does not affect the material spreading of the material spreading roller 7. Therefore, a plurality of horizontal material falling channels 41 and vertical material falling channels 31 are correspondingly provided. An opening is provided at the side end of the main shaft 3 at the top of each vertical material falling channel 31. When each opening rotates axially along with the main shaft 3, it faces the feeding channel 51 for feeding in turn.

[0026] In an embodiment of the present invention, optionally, as Figure 1 , Figure 3 , Figure 4 , Figure 5 shown, an end plate 15 is provided at the end of the material spreading roller 7. The end plate 15 is fixedly connected to the bottom end of the side connecting blade 8. Preferably, the end plate 15 can be integrally formed with the side connecting blade 8. On the one hand, it realizes the rotational connection of the material spreading roller 7 to the outer bottom end of the stirring blade 4. On the other hand, it avoids the leakage of the material spreading from the strip-shaped groove 71 along both ends of the groove. A roller shaft 72 is fixedly connected to the end of the material spreading roller 7. One end of the roller shaft 72 penetrates through the end plate 15 and is connected with a gear 16. A tooth-like structure meshing with the gear 16 is provided on the annular platform 10, that is, a design similar to an annular rack. Thus, when the main shaft 3 rotates axially, the gear 16 meshes and travels along the annular platform 10, driving the axial rotation of the gear 16 and driving the axial rotation of the roller shaft 72 and the material spreading roller 7.

[0027] Among them, the annular platform 10 can be designed as a single-layer structure, that is, a tooth-like structure meshing with the gear 16 is provided on the top surface of the annular platform 10. The annular platform 10 can also be designed as an upper and lower double-layer structure, as Figure 1 , Figure 3 shown. For example, the upper annular platform 10 is designed as a flat plate for limiting the movement of the gear 16, and a tooth-like structure meshing with the gear 16 is provided on the top surface of the lower annular platform 10. More preferably, the upper and lower annular platforms 10 can also elastically clamp the gear 16, which is beneficial to the more stable meshing rotation of the gear 16.

[0028] As another optional embodiment of the present invention, as Figure 10 , Figure 11 shown, one end of the roller shaft 72 penetrates into the main shaft 3 and is connected with a cam 17. A thin shaft 18 is arranged in parallel in the vertical material falling channel 31. The bottom end of the thin shaft 18 penetrates out of the vertical material falling channel 31. A sealing bellows 19 is connected between the bottom end of the thin shaft 18 located in the vertical material falling channel 31 and the vertical material falling channel 31. Thus, when the material spreading roller 7 rotates axially, it drives the cam 17 to rotate synchronously, which is used to push the thin shaft 18 to vibrate up and down, and then drives the sealing bellows 19 to reciprocally expand and contract up and down. The sealing bellows 19 plays a role of sealing on the one hand and reciprocally expanding and contracting up and down to prevent blockage of the pipeline at the turning point on the other hand.

[0029] Specifically, a roller can also be connected to the bottom end of the thin shaft 18, and the roller abuts against the cam 17.

[0030] Preferably, a breaker hammer can also be connected to the top end of the thin shaft 18 located in the vertical blanking channel 31. Along with the up-and-down vibration of the thin shaft 18, it also serves to prevent blockage of the material at the top turning point in the vertical blanking channel 31.

[0031] As another alternative embodiment of the present invention, as Figure 9 shown, the scraper 9 can also be symmetrically arranged in the side connecting leaves 8 on both sides. The bottom end of the horizontal blanking channel 41 is rotatably connected with a traveling wheel 20. Among them, the length of the strip-shaped groove 71 is less than the length of the material spreading roller 7. The bottom end of the traveling wheel 20 is attached to the outer end of the material spreading roller 7 and travels, that is, the traveling wheel 20 travels at the outer end of the strip-shaped groove 71. One side of the traveling wheel 20 is connected with a wire winding wheel, and a pulling rope 21 is wound around the wire winding wheel. One end of the pulling rope 21 penetrates into the side connecting leaf 8 and is connected with the scraper 9. Thus, as Figure 9 shown, the scraper 9 can be arranged in the side connecting leaves 8 on both sides. When the material spreading roller 7 rotates axially, it drives the traveling wheel 20 to rotate synchronously, so that the pulling rope 21 on one side is tensioned. The tensioned pulling rope 21 pulls the scraper 9, so that the scraper 9 on the same side cannot elastically extend. If the material spreading roller 7 rotates in the reverse direction, it drives the traveling wheel 20 to rotate in the reverse direction, then the pulling rope 21 on the other single side is tensioned, so that the scraper 9 on the same side still cannot elastically extend. That is, the function of single-side material spreading and the single-side scraper 9 popping out and scraping the liquid mass is also realized.

[0032] The present invention also provides an oxidation preparation method for a catalyst carrier used in polyimide synthesis, including the following steps: During oxidation preparation, concentrated sulfuric acid or a mixed acid solution is put into the reaction kettle 1 through the feeding port 100, and then graphite material is put in through the feeding port 61. The feeding sequentially falls along the feeding pipe 6, the feeding channel 51, and the vertical blanking channel 31, and is pushed in the horizontal blanking channel 41. At the same time, the main shaft 3 is controlled to rotate axially, driving the stirring blades 4 to mix and stir. During the rotation of the stirring blades 4, the material spreading roller 7 is driven to rotate axially through the annular platform 10, so that the material pushed in the horizontal blanking channel 41 sequentially falls into the strip-shaped groove 71. When the strip-shaped groove 71 turns away from the side connecting leaf 8 on one side, the feeding is scattered into the kettle. When the strip-shaped groove 71 turns into the bottom end of the side connecting leaf 8 on the other side, the scraper 9 elastically extends downward and abuts against the outer side of the material spreading roller 7, preventing the acid liquid in the kettle from entering the horizontal blanking channel 41 along the material spreading roller 7; After low-temperature pre-oxidation, strong oxidants such as potassium permanganate are slowly added in batches through the feeding port 61, and the potassium permanganate powder is scattered into the kettle as the strip-shaped groove 71 rotates; After the material spreading is completed, the temperature inside the kettle is controlled to rise and continuous stirring is carried out to conduct a sufficient deep oxidation reaction. Then, liquid materials such as deionized water and hydrogen peroxide are introduced through the feed port 61 to terminate the reaction, remove the excessive potassium permanganate, and obtain a graphene oxide dispersion. The dispersion is discharged from the drain port 101 at the bottom of the reaction kettle 1, and then a graphene support material is prepared through subsequent processes such as washing, drying, calcination, and screening.

[0033] Those of ordinary skill in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present invention is limited to these examples; under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above, and they are not provided in detail for the sake of brevity.

Claims

1. An oxidation preparation device for a catalyst carrier used in polyimide synthesis, including a reaction kettle (1), wherein a stirring mechanism is provided in the reaction kettle (1), and it is characterized in that: The stirring mechanism includes a main shaft (3), a stirring blade (4) is horizontally connected to the side end of the main shaft (3), a shaft sleeve (5) is fixedly provided at the top end inside the reaction kettle (1), the shaft sleeve (5) is sleeved outside the main shaft (3), a feed pipe (6) is externally connected to the side end of the shaft sleeve (5), a vertical feeding channel (31) is opened inside the main shaft (3), a horizontal feeding channel (41) is opened at the bottom end inside the stirring blade (4), and the feed falls along the feed pipe (6) and the vertical feeding channel (31) in sequence, and is pushed along the horizontal feeding channel (41). A material spreading roller (7) is provided along the length direction at the outer bottom end of the stirring blade (4), a plurality of strip-shaped grooves (71) are arranged at intervals on the outer circumference of the material spreading roller (7), the length direction of the strip-shaped grooves (71) is parallel to the length direction of the material spreading roller (7), side connecting blades (8) are fixedly connected to both sides of the bottom end of the stirring blade (4), the bottom ends of the side connecting blades (8) are attached to the material spreading roller (7), and a scraping plate (9) is provided inside at least one side of the side connecting blades (8). An annular platform (10) is arranged along the circumference inside the reaction kettle (1), the annular platform (10) is in driving connection with the end of the material spreading roller (7) away from the main shaft (3), when the main shaft (3) rotates axially, the material spreading roller (7) is driven to rotate axially through the annular platform (10), so that the material pushed in the horizontal feeding channel (41) falls into the strip-shaped grooves (71) in sequence, and when the strip-shaped grooves (71) rotate away from one side of the side connecting blade (8), the feed is scattered into the kettle, and the scraping plate (9) inside the other side connecting blade (8) elastically extends downward and abuts against the outside of the material spreading roller (7).

2. The oxidation preparation device of a catalyst carrier for polyimide synthesis according to claim 1, characterized in that, A spiral coil pipe (11) is provided inside the reaction kettle (1), both ends of the spiral coil pipe (11) are respectively connected with a liquid receiving pipe (12), and the liquid receiving pipe (12) vertically penetrates out of the reaction kettle (1).

3. The oxidation preparation device for a catalyst carrier used in polyimide synthesis according to claim 2, characterized in that, A baffle plate (13) is fixedly connected to the inner side of the spiral coil pipe (11), a plurality of baffle plates (13) are arranged at intervals along the inner circumference of the spiral coil pipe (11), and the annular platform (10) is fixedly connected to the inner side of the baffle plate (13).

4. The oxidation preparation device of a catalyst carrier for polyimide synthesis according to claim 1, characterized in that, A plurality of stirring blades (4) are arranged at intervals along the outer circumference of the main shaft (3), and are arranged in multiple layers at intervals along the up and down direction of the main shaft (3).

5. An oxidation preparation device for a catalyst carrier for polyimide synthesis according to claim 1, characterized in that, End plates (15) are provided at the ends of the material spreading roller (7), the end plates (15) are fixedly connected to the bottom ends of the side connecting blades (8), a roller shaft (72) is fixedly connected to the end of the material spreading roller (7), one end of the roller shaft (72) penetrates out of the end plate (15) and is connected with a gear (16), and a toothed structure meshing with the gear (16) is provided on the annular platform (10).

6. The oxidation preparation device for the catalyst carrier used in polyimide synthesis according to claim 5, characterized in that, One end of the roller shaft (72) penetrates into the main shaft (3) and is connected with a cam (17). A thin shaft (18) is arranged in parallel in the vertical blanking channel (31). The bottom end of the thin shaft (18) penetrates out of the vertical blanking channel (31). A sealing bellows (19) is connected between the bottom end of the thin shaft (18) located in the vertical blanking channel (31) and the vertical blanking channel (31). When the material spreading roller (7) rotates axially, it drives the cam (17) to rotate synchronously, so as to push the thin shaft (18) to vibrate up and down.

7. The oxidation preparation device of a catalyst carrier for polyimide synthesis according to claim 6, characterized in that, A crushing hammer is connected to the top end of the thin shaft (18) located in the vertical blanking channel (31).

8. An oxidation preparation device for a catalyst carrier for polyimide synthesis according to claim 1, characterized in that, The scraping plates (9) are symmetrically arranged in the side connecting leaves (8) on both sides. A traveling wheel (20) is rotatably connected to the bottom end of the horizontal blanking channel (41). The bottom end of the traveling wheel (20) is attached to the outer end of the material spreading roller (7) to travel. One side of the traveling wheel (20) is connected with a wire winding wheel, and a pulling rope (21) is wound on the wire winding wheel. One end of the pulling rope (21) penetrates into the side connecting leaf (8) and is connected with the scraping plate (9). When the material spreading roller (7) rotates axially, it drives the traveling wheel (20) to rotate synchronously, so that the pulling rope (21) on one side is tensioned. The tensioned pulling rope (21) pulls the scraping plate (9), so that the scraping plate (9) on the same side cannot elastically extend.

9. An oxidation preparation method of a catalyst carrier for polyimide synthesis, which is prepared by using the oxidation preparation device of the catalyst carrier for polyimide synthesis described in any one of claims 1-8, characterized in that, It includes the following steps: During oxidation preparation, concentrated sulfuric acid or a mixed acid solution is put into the reaction kettle (1) through the feeding port (100), and then graphite material is put in through the feeding port (61). The feed falls successively along the feed pipe (6), the feed channel (51), and the vertical blanking channel (31), and is pushed in the horizontal blanking channel (41). At the same time, the main shaft (3) is controlled to rotate axially to drive the stirring blades (4) to mix and stir. During the rotation of the stirring blades (4), the material spreading roller (7) is driven to rotate axially through the annular platform (10), so that the material pushed in the horizontal blanking channel (41) falls into the strip-shaped grooves (71) in sequence. When the strip-shaped grooves (71) rotate away from the side connecting leaf (8) on one side, the feed is scattered into the kettle. When the strip-shaped grooves (71) rotate into the bottom end of the side connecting leaf (8) on the other side, the scraping plate (9) elastically extends downward and abuts against the outer side of the material spreading roller (7), so as to prevent the acid liquid in the kettle from entering the horizontal blanking channel (41) along the material spreading roller (7). After pre-oxidation, potassium permanganate powder is added slowly in batches through the feeding port (61), and the potassium permanganate powder is scattered into the kettle along with the rotation of the strip-shaped grooves (71). After the material spreading is completed, the temperature in the kettle is controlled to rise and continuous stirring is carried out for the oxidation reaction to obtain a graphene oxide dispersion liquid. The dispersion liquid is led out from the drain port (101) at the bottom end of the reaction kettle (1), and then is made into a graphene carrier material through subsequent washing, drying, roasting, and screening processes.

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