A preparation method and a preparation device of a low-crack large-size SDB polymer ball

Abstract

The application relates to a preparation method and a preparation device of a low-crack large-size SDB polymer ball, and relates to a preparation method and a preparation device of an SDB polymer ball. The application aims to solve the technical problems of the existing method for preparing a large-size SDB ball, such as serious cracking, high breakage rate and great production difficulty. The application drives the water phase and the organic phase to couple movement through a reaction device, and continuously dissipates stress concentration generated in a polymerization process through the interaction between the water phase and the organic phase, so that the cracking and breakage probability of the polymer ball is effectively reduced. The application adopts an impregnation liquid with gradually rising water proportion to assist the slow shrinkage of the polymer ball before the first drying of the polymer ball, and the step can slow down the shrinkage rate of the porous polymer ball in the drying process, and avoid the cracking caused by the too large difference between the internal and external drying rates of the porous polymer ball in the drying process.

Description

Technical Field

[0001] This invention relates to a method and apparatus for preparing SDB polymer spheres. Background Technology

[0002] With the expansion of the nuclear power industry and the increasing demands for environmental protection, the treatment of radioactive nuclear waste has attracted widespread attention. The treatment of the hydrogen isotope tritium is a crucial aspect of radioactive element processing. During the operation of the nuclear industry, a large amount of tritium-containing wastewater is generated annually, and its treatment is of great significance to the development of the nuclear industry. Liquid-phase catalytic exchange (LPCE) is a highly efficient and energy-saving method for separating hydrogen isotopes, with extremely high application prospects. Hydrophobic catalysts are a key component in realizing liquid-phase catalytic exchange. Currently, international research on hydrophobic catalysts mainly focuses on PTFE-based catalysts and SDB (styrene-divinylbenzene copolymer)-based catalysts. SDB-based catalysts possess excellent hydrophobic properties and superior Pt loading performance, thus attracting widespread attention. However, the porous SDB catalyst supports produced by existing processes are relatively small in size. Large-size supports are difficult to produce and have low yields, which is not conducive to practical industrial applications. Li Xiuchun et al. from Southwest University of Science and Technology (Preparation of large-size SDB hydrophobic catalyst support and its influence on the resistance of the exchange column bed [D]. Southwest University of Science and Technology, 2016) tested and analyzed the mass transfer resistance of prepared hydrophobic catalysts of 1.3 mm, 2.4 mm and 3.3 mm. They found that under the same packing method, the smaller the particle size of the catalyst, the greater the resistance of gas passing through the catalyst bed, which led to a gradual increase in liquid between the catalyst pores, resulting in flooding and seriously affecting the efficiency of continuous catalyst operation. Therefore, the research on the preparation process of large-size SDB-based hydrophobic catalysts is of great significance for their practical industrial application. Wei Jun (Controllable preparation of SDB-based hydrophobic catalysts [D]. University of Science and Technology of China, 2015) prepared small-size hydrophobic catalysts of 0.2-1 mm using a co-current capillary-based microfluidic device with UV curing. They also prepared larger-size catalysts of 1-3 mm using a dropwise method, but the latter suffered from severe damage. Liu Cailin et al. (Preparation method of hydrophobic catalyst support for styrene-divinylbenzene copolymer [P]. 201410449037.2, 2014) prepared 2-5 mm hydrophobic supports using suspension polymerization. However, the catalyst supports prepared by suspension polymerization were not uniform in size and still need further screening. Dong Guojun et al. (A method for preparing size-controllable spherical SDB hydrophobic supports and Pt / SDB hydrophobic catalysts [P]. 202110265160.9, 2021) achieved controllable preparation of 3-10 mm large-size SDB spherical supports using suspension polymerization, improving the raw material utilization rate. However, the problem of spherical cracking still exists, resulting in relatively insufficient yield and affecting the mechanical properties of the catalyst. The cracking problem mainly occurs during the polymerization process of polymer sphere production and the first drying process of polymer spheres. Achieving stable and controllable preparation of large-size SDB hydrophobic catalyst supports and solving the problem of large-size support cracking is of great significance for realizing and expanding the industrial application of superhydrophobic catalysts. Summary of the Invention

[0003] The present invention aims to solve the technical problems of severe cracking, high breakage rate and high production difficulty in the preparation of large-size SDB spheres by existing methods, and proposes a method and apparatus for preparing large-size SDB polymer spheres with low cracking.

[0004] The method for preparing a low-crack, large-size SDB polymer sphere according to the present invention is carried out according to the following steps:

[0005] 1. Prepare a low surface tension aqueous solution by mixing the surfactant with distilled water;

[0006] Styrene, divinylbenzene, toluene and n-heptane were mixed uniformly, then benzoyl peroxide was added, followed by p-dichlorobenzene to obtain an organic phase mixture with a density greater than that of the aqueous phase solution by 0.5% to 2%. The organic phase mixture was heated in a water bath at 75℃ to 80℃ for 45 min to 50 min.

[0007] The mass ratio of the surfactant to distilled water is 1:(500-550);

[0008] The molar ratio of styrene, divinylbenzene, toluene and n-heptane is 2:(1-3):(1-3):(2-5);

[0009] The mass of benzoyl peroxide is 7% to 8% of the mass of styrene;

[0010] 2. Add the aqueous phase solution and organic phase solution prepared in step 1 to the reaction tube. Set the reaction tube at an angle of 40° to 50° to the horizontal plane. The bottom of the reaction tube is flat and the outer edge of the bottom of the reaction tube is arc-shaped. Place the bottom of the reaction tube in a water bath at 75°C to 85°C. Then, the reaction tube rotates and carries out a constant temperature polymerization reaction for 3.5h to 4h. Solidified polymer balls are obtained at the bottom of the reaction tube.

[0011] The volume of the aqueous solution is 0.25πR. 3 ×(1~1.3), where R is the inner diameter of the reaction tube; the volume of the organic phase solution is 1 to 1.3 times the volume of the target polymer spheres;

[0012] The rotation speed is 50 rpm to 200 rpm;

[0013] 3. Remove the solidified polymer balls from the reaction tube, then transfer the solidified polymer balls to a Soxhlet extraction apparatus. Use acetone as a washing agent to extract for 12-24 hours to remove impurities. After the extraction is completed, transfer the polymer balls to anhydrous ethanol liquid phase. Then add distilled water every 30 minutes, so that the molar percentage of water in the water and anhydrous ethanol mixture increases to more than 94% at a rate of <6% / 30min. Let it stand for 30min, then transfer it to distilled water for immersion for 30min. Then take it out and let it air dry to obtain dried polymer balls.

[0014] In this step, after the extraction operation, the external liquid environment of the SDB polymer spheres is changed to make the SDB spheres shrink in a controlled manner, so as to prevent the polymer spheres from being damaged by excessive difference in the shrinkage rate between the inner and outer layers of the spheres. The specific implementation method is to immerse the extracted SDB spheres in an alcohol, acetone or methanol liquid environment, and then increase the water content in the liquid environment at a rate of not less than 17 times and an average speed of not more than 0.2% / min, so as to achieve the controlled shrinkage of the SDB polymer spheres.

[0015] 4. Place the dried polymer balls in an agate grinding jar, add 40-mesh quartz sand and agate grinding balls, adjust the speed of the ball mill to 100 rpm to 120 rpm, and ball mill for 180 min to 200 min. Then wash and dry the polymer balls to obtain SDB polymer balls.

[0016] The mass ratio of the polymer balls, quartz sand and agate grinding balls is (0.8-1):5:3.

[0017] This invention discloses a process and equipment for producing large-size, low-crack SDB spheres by driving the coupled motion of an aqueous phase and an organic phase during polymerization. The core of this invention is to drive the coupled motion of the aqueous and organic phases through a reaction device. The interaction between the aqueous and organic phases continuously dissipates stress concentration generated during polymerization, thereby effectively reducing the probability of polymer sphere cracking and breakage. The organic phase refers to the polymer preparation solution composed of monomers, crosslinking agents, pore-forming agents, initiators, and density modifiers (e.g., styrene as monomer, divinylbenzene as crosslinking agent, toluene and n-heptane as pore-forming agents, benzoyl peroxide as initiator, and p-dichlorobenzene as density modifier); the aqueous phase refers to a low-surface-tension solution composed of water and surfactants. The density of the organic phase is slightly greater than that of the aqueous phase under the action of the density modifier (p-dichlorobenzene); after the organic phase is added to the aqueous phase, it agglomerates at the bottom of the aqueous phase to form stable liquid spheres. In the coupled motion, the organic phase rotates at a fixed point within the aqueous phase. As the reaction proceeds, the organic phase gradually transforms from a liquid to a solid state. During this process, the friction between the aqueous and organic phase interfaces and the stress changes within the organic phase result in more uniform and stable solid polymer spheres with a significant reduction in stress concentration. After extraction and washing, the solid polymer spheres are placed in an alcohol impregnation solution, and the water content in the impregnation environment is gradually increased to assist in the slow shrinkage of the polymer spheres. After natural drying, the spheres are ground to increase their surface roughness. After washing and drying, large-sized SDB sphere catalyst supports with low cracking are obtained. In this process, in addition to alcohol, various liquids such as acetone and methanol can be used as impregnation solutions.

[0018] The present invention discloses a device for preparing large-size SDB polymer spheres with low cracking. The device comprises multiple hollow shaft tubes arranged in a multi-row array. The hollow shaft tubes are inclined at 40°–50° to the horizontal plane. The transmission method is driven by a constant-speed motor, which outputs power to the drive shafts of each row via synchronous pulleys and single-sided synchronous belts. Power is then transmitted to each hollow shaft tube via double-sided synchronous belts and synchronous pulleys. The hollow shaft tubes serve as the loading positions for the reaction tubes. The upper part of the outer wall of the reaction tube is covered with elastic rubber material. The reaction tube is inserted into the hollow shaft tube and rotates with it. Adjacent hollow shaft tubes maintain a spacing of R×(2–3) and are connected by synchronous pulleys and synchronous belts to form a transmission array for power transmission. A water bath is provided below the hollow shaft tubes, and the bottom of the reaction tube is immersed in the water bath.

[0019] Corresponding to step two of the process method proposed in this invention, this invention discloses an array-type two-phase coupled rotary polymerization production device suitable for this process method. The device is driven by a constant-speed motor, with a transmission component consisting of a synchronous pulley and a hollow shaft tube, which, together with a synchronous belt, forms a transmission array. A flat-bottomed glass tube with a certain curvature at its bottom edge serves as the reaction tube. During operation, a certain amount of organic phase and aqueous phase are added to each reaction tube and loaded into each hollow shaft tube. The device drives each reaction tube to rotate at a uniform speed. The rotation axis of the hollow shaft tube of this process device maintains a certain designed tilt angle with the vertical direction, allowing the organic phase to rotate and roll in the reaction tube in a unique motion. The bottom of the reaction tube extends from the bottom of the device, and a water bath is used to heat the reaction tube. After polymerization at a certain temperature for several hours, crude polymer spheres are obtained.

[0020] Compared with the prior art, the present invention has the following features and beneficial effects:

[0021] 1. This invention employs a two-phase coupled rotational polymerization method for the polymerization and curing of SDB spheres. During the reaction, the organic phase rotates and rolls under the combined action of the inner wall of the reaction tube, gravity, and liquid phase motion. The rotational motion is controlled at a low intensity to avoid damaging the integrity of the organic phase droplets. At the same time, the stress concentration formed by the organic phase during the curing process can be fully dissipated, which can greatly reduce the cracking during the preparation of large-size polymer spheres.

[0022] 2. In this invention, the organic phase can automatically aggregate into spheres after being added to the aqueous phase under the rotation of the equipment without manual intervention, reducing the amount of manual operation; in addition, the coupled rotation makes it less likely for the reaction tube wall to form scale due to the adhesion of reactants, reducing the workload of cleaning the reaction tube.

[0023] 3. In step three of this invention, before the polymer balls are dried for the first time, an impregnation solution with a gradually increasing water content is used to assist the polymer balls in slow shrinkage. This step can slow down the shrinkage rate of the porous polymer balls during the drying process and avoid cracking caused by an excessive difference in the drying rate between the inside and outside of the porous polymer balls during the drying process.

[0024] 4. The production equipment proposed in this invention uses an inclined rotating reaction tube to drive the aqueous phase and the organic phase to achieve a fixed-point rotational motion of the organic phase. The fixed point of rotational motion is the center of the organic phase liquid sphere. There are no stationary points on the entire surface of the organic phase sphere. This allows the equipment to meet the needs of the two-phase coupled rotational polymerization method with a relatively simple structure and low cost. The production effect is stable, the production capacity of large-size SDB spheres is improved, the operation is simple, and it is suitable for mass production.

[0025] The equipment and methods described above can be used to produce large-sized polymer spheres with uniform sphere size, fewer cracks, and the crack suppression effect is related to the rotational motion of the organic phase spheres. Attached Figure Description

[0026] Figure 1 A three-dimensional schematic diagram of the apparatus used in step two of Experiment 1;

[0027] Figure 2 A front view of the apparatus used in step two of Experiment 1;

[0028] Figure 3 This is a schematic diagram of reaction tube 3 in step two of the polymerization reaction in Experiment 1;

[0029] Figure 4 A top view of the transfer section of the device used in step two of Experiment 1 (only 3 rows are shown);

[0030] Figure 5 Physical images of SDB spheres of different sizes prepared for Experiment 11 and Experiments 17-19;

[0031] Figure 6 The static hydrophobic angle of the polymer spheres prepared for Experiment 11;

[0032] Figure 7 These are microscopic images of the surface of the polymer spheres prepared in Experiment 11;

[0033] Figure 8 This is a longitudinal section image of the surface cracks on the polymer spheres prepared in Experiment 11;

[0034] Figure 9 yes Figure 8 Image of a longitudinal section of the crack within the Chinese frame. Detailed Implementation

[0035] Specific Implementation Method 1: This implementation method is a method for preparing large-size SDB polymer spheres with low cracking, specifically carried out according to the following steps:

[0036] 1. Prepare a low surface tension aqueous solution by mixing the surfactant with distilled water;

[0037] Styrene, divinylbenzene, toluene and n-heptane were mixed uniformly, then benzoyl peroxide was added, followed by p-dichlorobenzene to obtain an organic phase mixture with a density greater than that of the aqueous phase solution by 0.5% to 2%. The organic phase mixture was heated in a water bath at 75℃ to 80℃ for 45 min to 50 min.

[0038] The mass ratio of the surfactant to distilled water is 1:(500-550);

[0039] The molar ratio of styrene, divinylbenzene, toluene and n-heptane is 2:(1-3):(1-3):(2-5);

[0040] The mass of benzoyl peroxide is 7% to 8% of the mass of styrene;

[0041] 2. Add the aqueous phase solution and organic phase solution prepared in step 1 to the reaction tube. Set the reaction tube at an angle of 40° to 50° to the horizontal plane. The bottom of the reaction tube is flat and the outer edge of the bottom of the reaction tube is arc-shaped. Place the bottom of the reaction tube in a water bath at 75°C to 85°C. Then, the reaction tube rotates and carries out a constant temperature polymerization reaction for 3.5h to 4h. Solidified polymer balls are obtained at the bottom of the reaction tube.

[0042] The volume of the aqueous solution is 0.25πR. 3 ×(1~1.3), where R is the inner diameter of the reaction tube; the volume of the organic phase solution is 1 to 1.3 times the volume of the target polymer spheres;

[0043] The rotation speed is 50 rpm to 200 rpm;

[0044] 3. Remove the solidified polymer balls from the reaction tube and transfer them to a Soxhlet extraction apparatus. Use acetone as a washing agent to extract for 12-13 hours to remove impurities. After extraction, transfer the polymer balls to anhydrous ethanol liquid phase. Then add distilled water every 30 minutes to increase the molar percentage of water in the water and anhydrous ethanol mixture to over 94% at a rate of <6% / 30min. Let it stand for 30 minutes, then transfer it to distilled water for 30 minutes. Remove it and let it air dry to obtain dried polymer balls. 4. Place the dried polymer balls in an agate grinding jar, add 40-mesh quartz sand and agate grinding balls, adjust the ball mill speed to 100-120 rpm, and ball mill for 180-200 minutes. Then wash and dry the polymer balls to obtain SDB polymer balls.

[0045] The mass ratio of the polymer balls, quartz sand and agate grinding balls is (0.8-1):5:3.

[0046] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the surfactant mentioned in step one is one or a mixture of perfluorooctanoic acid, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium hexadecylbenzenesulfonate. Everything else is the same as in Specific Implementation Method One.

[0047] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the reaction tube is positioned at a 45° angle to the horizontal plane in step two. Everything else is the same as in Specific Implementation Method One or Two.

[0048] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that: in step two, the inner diameter of the reaction tube is r × (2.5–4), where r is the radius of the target polymer sphere; the bottom of the reaction tube is flat, and the corners between the bottom and sides of the reaction tube are rounded, with the inner wall rounded to a size of r × (1.3–1.5), where r is the radius of the target polymer sphere. Everything else is the same as in Specific Implementation Methods One to Three.

[0049] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method Four in that the inner diameter of the reaction tube in step two is 24mm, the outer diameter is 26mm, and the inner diameter of the hollow shaft tube is 27mm. Everything else is the same as in Specific Implementation Method Four.

[0050] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method Five in that the mass ratio of the polymer balls, quartz sand, and agate grinding balls mentioned in step four is 1:5:3. Everything else is the same as in Specific Implementation Method Five.

[0051] Specific Implementation Method Seven: This implementation method is the same as the preparation device for low-cracking large-size SDB polymer spheres in Specific Implementation Method One. It includes multiple hollow shaft tubes arranged in a multi-row array structure. The hollow shaft tubes are inclined at 40° to 50° with the horizontal plane. The transmission method is driven by a constant speed motor, which outputs power to the drive shaft of each row through a synchronous pulley and a single-sided synchronous belt. Then, it is transmitted to each hollow shaft tube through a double-sided synchronous belt and a synchronous pulley. The hollow shaft tube is the loading position of the reaction tube. The upper part of the outer wall of the reaction tube is covered with an elastic rubber material. The reaction tube is inserted into the hollow shaft tube and rotates with the hollow shaft tube. A distance of R×(2~3) is maintained between two adjacent hollow shaft tubes, where R is the inner diameter of the reaction tube. They are connected by a synchronous pulley and a synchronous belt to form a transmission array to realize power transmission. A water bath is set below the hollow shaft tube, and the bottom of the reaction tube is immersed in the water bath.

[0052] The invention was verified using the following experiments:

[0053] Experiment 1: This experiment demonstrates a method for preparing large-sized SDB polymer spheres with low cracking, specifically carried out according to the following steps:

[0054] 1. Prepare a low surface tension aqueous solution by mixing a surfactant with distilled water; wherein the surfactant is perfluorooctanoic acid; and the mass ratio of the surfactant to distilled water is 1:500.

[0055] Styrene, divinylbenzene, toluene, and n-heptane were uniformly mixed, then benzoyl peroxide was added, followed by p-dichlorobenzene to obtain an organic phase mixture with a density greater than that of the aqueous solution. The organic phase mixture was heated in a water bath at 75°C for 45 minutes; the density of the aqueous phase was approximately 1 g / cm³. 3 The organic phase was adjusted to 1.01 g / cm³. 3;

[0056] The molar ratio of styrene, divinylbenzene, toluene, and n-heptane is 1:1:1:2;

[0057] The mass of benzoyl peroxide is 7.5% of the mass of styrene;

[0058] 2. Add 10 mL of the aqueous phase solution and 1 mL of the organic phase solution prepared in step 1 to the reaction tube. Set the reaction tube at a 45° angle to the horizontal plane. The bottom of the reaction tube is flat and there is a 5 mm chamfer between the bottom and the side of the reaction tube. Place the bottom of the reaction tube in an 80°C water bath. Then, the reaction tube rotates and carries out a constant temperature polymerization reaction for 3.5 h. Solidified polymer balls are obtained at the bottom of the reaction tube.

[0059] The reaction tube has an inner diameter of 24mm and an outer diameter of 26mm, with 5mm rounded corners on the sides and bottom; the hollow shaft tube has an inner diameter of 27mm.

[0060] The rotation speed is 50 rpm;

[0061] like Figures 1-4 As shown, it is the device used in step two, which is composed of a constant speed motor 1, multiple hollow shaft tubes 2, reaction tube 3, single-sided synchronous belt 4, transmission shaft 5, double-sided synchronous belt 6, water bath 7, bracket 8, idler wheel 9, first synchronous pulley 10 and second synchronous pulley 11.

[0062] The constant speed motor 1 is fixed on the bracket 8, and the rotating shaft 1-1 of the constant speed motor 1 is at a 45° angle to the horizontal plane; the multiple hollow shaft tubes 2 are arranged in a square array and fixed directly above the water bath 7, with a 60mm gap between two adjacent hollow shaft tubes 2, both ends of the hollow shaft tubes 2 are open, and the hollow shaft tubes 2 are at a 45° angle to the horizontal plane; the upper part of the outer wall of the reaction tube 3 is covered with elastic rubber material, and each reaction tube 3 is inserted into a hollow shaft tube 2. The elastic rubber material generates friction, which makes the reaction tube 3 and the hollow shaft tube 2 tightly fixed together;

[0063] like Figure 1As shown, the constant speed motor 1 is located at the top right. Each position in the rightmost column has one drive shaft 5. The rightmost column does not have hollow shaft tubes 2. The upper end of the top right drive shaft 5 is connected to the rotating shaft 1-1. Two second synchronous pulleys 11 are fixed to the top right drive shaft 5, and the two second synchronous pulleys 11 are coaxially arranged. A hollow shaft tube 2 is fixed to each position except the rightmost column, and a first synchronous pulley 10 is fixed to the outer wall of each hollow shaft tube 2. Two second synchronous pulleys are fixed to the bottom right drive shaft 5. 11. Two second synchronous pulleys 11 are arranged coaxially. Three second synchronous pulleys 11 are fixed on the drive shaft 5 of the rightmost column, excluding the top and bottom. Two of the second synchronous pulleys 11 are connected to the adjacent drive shafts 5 of the previous and next rows respectively by a single-sided synchronous belt 4. The other second synchronous pulley 11 is connected to the first synchronous pulley 10 fixed on the other drive shafts 5 in the same row by a double-sided synchronous belt 6. The double-sided synchronous belt 6 alternately winds around each first synchronous pulley 10. Two idler pulleys 9 are also provided in each row.

[0064] The transmission method is driven by a constant speed motor 1, which outputs power to the drive shafts 5 of each row through the second synchronous pulley 11 and the single-sided synchronous belt 4. The power is then transmitted to each hollow shaft tube 2 through the double-sided synchronous belt 6 and the first synchronous pulley 10. The hollow shaft tube 2 is the loading position of the reaction tube 3. The upper part of the outer wall of the reaction tube 3 is covered with elastic rubber material. The reaction tube 3 is inserted into the hollow shaft tube 2 and rotates with the hollow shaft tube. A 60mm gap is maintained between two adjacent hollow shaft tubes 2, and they are connected by synchronous pulleys and synchronous belts to form a transmission array to realize power transmission. A water bath 7 is set below the hollow shaft tube 2, and the bottom of the reaction tube 3 is immersed in the water bath.

[0065] 3. Remove the solidified polymer balls from the reaction tube and transfer them to a Soxhlet extraction apparatus. Use acetone as a washing agent to extract for 12 hours to remove impurities. After extraction, transfer the polymer balls to anhydrous ethanol liquid phase. Then add distilled water every 30 minutes to increase the molar percentage of water in the water and anhydrous ethanol mixture to 95% at a rate of 5% / 30 minutes. Let it stand for 30 minutes, then transfer it to distilled water for 30 minutes. Finally, remove it and let it air dry to obtain dried polymer balls.

[0066] 4. Place the dried polymer balls in an agate grinding jar, add 40-mesh quartz sand and agate grinding balls (outer diameter 10mm), adjust the speed of the ball mill to 100rpm, and ball mill for 180min. Then wash and dry the polymer balls to obtain SDB polymer balls.

[0067] The mass ratio of the polymer balls, quartz sand, and agate grinding balls is 1:5:3.

[0068] Experiments 2-16 were also conducted. The differences in process parameters for each experiment are shown in Table 1. Parameters not marked are the same as those in Experiment 1.

[0069] Table 1. Size, yield, BET specific surface area, and compressive strength of the SDB polymer spheres prepared in Experiments 1-16

[0070]

[0071] According to the data in Table 1, the polymerization time in step two should be controlled between 4h and 4.5h, and the rotation speed in step two should be controlled between 100rpm and 150rpm to achieve better production results.

[0072] Using this method, SDB polymer spheres of the desired size can be produced directionally by controlling the amount of organic phase solution added to the reaction tube. Experiments 17-19 were conducted, differing from Experiment 11 in that the amount of organic phase added in step 2 was 0.75 mL, 1.25 mL, and 1.5 mL, respectively; all other operations were identical to Experiment 11. Figure 5 These are physical images of SDB spheres of different sizes prepared in Experiments 11 and 17-19. From top to bottom, they correspond to Experiments 17, 11, 18, and 19, respectively. It can be seen that the more organic phases added, the larger the final size of the SDB spheres. Moreover, the size and morphology of the SDB spheres in each batch are uniform and stable, with very few cracking problems and relatively large particles.

[0073] Figure 6 The static hydrophobic angle of the polymer spheres prepared in Experiment 11 indicates that the SDB polymer spheres prepared by this method have excellent hydrophobic properties.

[0074] Figure 7 These are microscopic images of the surface of the polymer spheres prepared in Experiment 11. Figure 8 This is a longitudinal section image of the surface cracks on the polymer sphere prepared in Experiment 11. Figure 9 yes Figure 8 The three images of the crack cross section within the Chinese frame demonstrate that the large-sized SDB spheres prepared by the method proposed in this invention have a uniform surface morphology and no through-cracks. The sphere surface has some fine lines, but the depth is about 55 μm, which is less than 1% of the sphere diameter, indicating that no cracks that seriously affect the mechanical properties of the spheres have occurred.

[0075] This invention enables the stable production of large-scale SDB spheres with low cracking, solving the problems of high production difficulty and high breakage rate of large-size SDB catalyst supports. The SDB spheres produced by this invention have excellent size and morphology, and their hydrophobicity and loading performance can well meet the requirements of hydrophobic catalyst supports, making them suitable for large-scale industrial processing environments. They can effectively avoid the problems of high mass transfer resistance and severe flooding caused by excessively small catalyst size.

Claims

1. A process for the preparation of low crack large size SDB polymer balls, characterized by The preparation method of low-crack, large-size SDB polymer spheres is carried out according to the following steps:

1. Prepare a low surface tension aqueous solution by mixing the surfactant with distilled water; Styrene, divinylbenzene, toluene and n-heptane were mixed uniformly, then benzoyl peroxide was added, followed by p-dichlorobenzene to obtain an organic phase mixture with a density greater than that of the aqueous phase solution by 0.5% to 2%. The organic phase mixture was heated in a water bath at 75℃ to 80℃ for 45 min to 50 min. The mass ratio of the surfactant to distilled water is 1:(500~550); The molar ratio of styrene, divinylbenzene, toluene and n-heptane is 2:(1~3):(1~3):(2~5); The mass of benzoyl peroxide is 7% to 8% of the mass of styrene.

2. Add the aqueous phase solution and organic phase solution prepared in step 1 to the reaction tube. Set the reaction tube at an angle of 40° to 50° to the horizontal plane. The bottom of the reaction tube is flat and the outer edge of the bottom of the reaction tube is arc-shaped. Place the bottom of the reaction tube in a water bath at 75°C to 85°C. Then, the reaction tube rotates and carries out a constant temperature polymerization reaction for 3.5h to 4h. Solidified polymer balls are obtained at the bottom of the reaction tube. The volume of the aqueous phase solution is 0.25πR³×(1~1.3), where R is the inner diameter of the reaction tube; the volume of the organic phase solution is 1 to 1.3 times the volume of the target polymer spheres. The rotation speed is 50 rpm to 200 rpm; 3. Remove the solidified polymer balls from the reaction tube, then transfer the solidified polymer balls to a Soxhlet extraction apparatus. Use acetone as a washing agent to extract for 12-24 hours to remove impurities. After the extraction is completed, transfer the polymer balls to anhydrous ethanol liquid phase. Then add distilled water every 30 minutes, so that the molar percentage of water in the water and anhydrous ethanol mixture increases to more than 94% at a rate of <6% / 30min. Let it stand for 30min, then transfer it to distilled water for immersion for 30min. Then take it out and let it air dry to obtain dried polymer balls.

4. Place the dried polymer balls in an agate grinding jar, add 40-mesh quartz sand and agate grinding balls, adjust the speed of the ball mill to 100 rpm to 120 rpm, and ball mill for 180 min to 200 min. Then wash and dry the polymer balls to obtain SDB polymer balls. The mass ratio of the polymer balls, quartz sand and agate grinding balls is (0.8~1):5:

3.

2. A process for the preparation of a low check large size SDB polymer ball as claimed in claim 1, wherein The surfactant mentioned in step one is one or a mixture of several of perfluorooctanoic acid, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium hexadecylbenzenesulfonate.

3. A process for the preparation of a low check large size SDB polymer ball as claimed in claim 1, wherein In step two, the reaction tube is positioned at a 45° angle to the horizontal plane.

4. The process for the preparation of a low check large size SDB polymer ball as claimed in claim 1, wherein In step two, the inner diameter of the reaction tube is r×(2.5~4), where r is the radius of the target polymer sphere; the bottom of the reaction tube is flat and the bottom and sides of the reaction tube are rounded, and the size of the inner wall fillet is r×(1.3~1.5), where r is the radius of the target polymer sphere.

5. The process for the preparation of a low check large size SDB polymer ball as claimed in claim 1, wherein The mass ratio of the polymer balls, quartz sand, and agate grinding balls mentioned in step four is 1:5:

3.

6. The method for preparing a low-crack, large-size SDB polymer sphere according to claim 1, characterized in that... The device used in step two includes multiple hollow shaft tubes arranged in a multi-row array structure. The hollow shaft tubes are inclined at 40°~50° to the horizontal plane. The transmission method is driven by a constant speed motor, which outputs power to the drive shaft of each row through synchronous pulleys and single-sided synchronous belts. Then, it is transmitted to each hollow shaft tube through double-sided synchronous belts and synchronous pulleys. The hollow shaft tubes are the loading positions of the reaction tubes. The upper part of the outer wall of the reaction tube is covered with elastic rubber material. The reaction tube is inserted into the hollow shaft tube and rotates with the hollow shaft tube. A distance of R×(2~3) is maintained between two adjacent hollow shaft tubes, where R is the inner diameter of the reaction tube. They are connected by synchronous pulleys and synchronous belts to form a transmission array to realize power transmission. A water bath is set below the hollow shaft tubes, and the bottom of the reaction tube is immersed in the water bath.

Images