Amplification preparation system for millimeter-scale mesoporous carbon spheres

Abstract

The invention relates to the technical field of inorganic mesoporous materials, in particular to an amplification preparation system of millimeter-scale mesoporous carbon spheres. The preparation method comprises the following steps: mixing a phenolic precursor aqueous solution, an aldehyde precursor aqueous solution and a silicon dioxide aqueous solution, and performing prepolymerization to obtain a prepolymer solution; dropwise adding the prepolymer solution into liquid paraffin oil, carrying out reversed-phase suspension polymerization reaction, and then carrying out aging treatment to obtain phenolic resin spheres; calcining the phenolic resin spheres in an inert atmosphere to obtain millimeter-scale carbon spheres; and carrying out etching treatment on the millimeter-level carbon spheres to obtain the millimeter-level mesoporous carbon spheres. The invention creatively provides a pre-polymerization-molding-aging combined system in the engineering mass production of the millimeter-scale mesoporous carbon spheres, determines an amplified preparation process, and defines the influence of process parameters on the product quality; the engineering synthesis steps of the millimeter-scale mesoporous carbon spheres are optimized, the synthesis uncertainty is reduced, the cost of raw materials is reduced, and the large-scale production is facilitated.

Description

Technical Field

[0001] This invention relates to the field of inorganic mesoporous materials technology, specifically to a scale-up preparation system for millimeter-scale mesoporous carbon spheres. Background Technology

[0002] Porous carbon catalysts possess high specific surface area, unique structure, tunable porosity, and excellent chemical stability, showing great potential in catalytic processes and environmental remediation. The preparation methods of porous carbon mainly involve calcining organic precursors. For example, Chinese patent CN120329500A describes a method using phenolic precursors and formaldehyde as carbon sources, benzene and its derivatives as pore expanders, and polymerizing them in the presence of emulsifiers and polymerization catalysts. The resulting carbon support is then calcined under an inert gas atmosphere, and its application in the positive electrode of rechargeable zinc-air batteries is explored. References Nat. Commu. 2024, 15, 983 describe the use of resorcinol and formaldehyde as carbon sources and tetrapropyl silicate as a pore-forming agent, exploring the effect of the time of pore-forming agent addition on the proportion of hollow spheres in mesoporous carbon, and revealing the mechanism of tetrapropyl silicate as a pore-forming agent. Reference J. Am. Chem. Soc. 2022, 144, 1634-1646 further develops the direct preparation of N-doped mesoporous carbon spheres using m-aminophenol and formaldehyde as carbon sources, and explores the effect of the amount of ammonia added as a catalyst on the formation of carbon spheres. Both of these references describe the preparation of powdered mesoporous carbon, and the preparation process involves the addition of catalysts and emulsifiers, making the process relatively complex.

[0003] In traditional fixed-bed reactors in chemical processes, the loading of this type of powdered mesoporous carbon catalyst requires pressing, crushing, and sieving to a specific diameter before being placed into the fixed bed. This method is time-consuming and labor-intensive, and the resulting powdered mesoporous carbon catalyst particles have weak strength, leading to increased pressure drop and potential hazards during production.

[0004] Correspondingly, millimeter-sized mesoporous carbon spheres combine the characteristics of high specific surface area, multiple carrier modification sites, and one-time molding, providing an excellent catalyst support option for application in fixed-bed reactors. Currently, the preparation method of millimeter-sized carbon spheres is mainly the template method. Chinese patent CN101817519A describes the use of furfural and resorcinol as carbon sources and block copolymers as pore-forming agents, which are stirred and polymerized in the presence of emulsifiers and polymerization catalysts, and then calcined under an inert atmosphere to obtain millimeter-sized carbon spheres. Chinese patent CN120483096A describes the use of polyacrylonitrile and carbon additive materials as carbon sources, which are formed by injection dropwise addition, carbonized under an inert atmosphere, calcined in a muffle furnace to create pores, and then obtained millimeter-sized carbon spheres. Chinese patent CN105126758A describes the use of resorcinol and formaldehyde as carbon sources, using self-made silica sol as a template agent, stirring and molding with paraffin oil, filtering and drying, alkali treatment to etch away the template agent, and then calcining to carbon under inert conditions. The literature Carbon. 2016, 96, 608-615 describes a method using resorcinol and formaldehyde as carbon sources, employing a self-made silica sol as a template agent, stirring with paraffin oil to form the carbon, filtering and drying it, then etching away the template agent with alkali treatment, and finally calcining it under inert conditions to produce carbon. This method increases the single-feed amount of resorcinol to 1.1 kg. However, these methods all have some shortcomings: for the first method, the presence of emulsifiers and polymerization catalysts exacerbates the uncertainty in the synthesis; the second method uses high-cost polyacrylonitrile, which is not conducive to scale-up production; the third method does not provide scale-up preparation conditions; and the fourth method only provides the scale-up feed amounts of each substance, without providing specific steps and operating equipment. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a scale-up preparation system for millimeter-sized mesoporous carbon spheres. This invention designs an integrated apparatus for the scale-up synthesis of millimeter-sized mesoporous carbon spheres, and conducts synthesis research within this apparatus. In terms of synthesis, aqueous solutions of phenolic and aldehyde precursors are used as carbon sources, and aqueous silica solution is used as a pore-forming agent. A uniform prepolymer is formed through prepolymerization, followed by reverse suspension polymerization to achieve droplet formation. Subsequently, calcination and carbonization are performed to construct the carbon framework, and finally, etching is used to remove silica particles, yielding millimeter-sized mesoporous carbon spheres. This invention overcomes the synthesis uncertainties caused by the introduction of emulsifiers and polymerization catalysts in traditional methods through a process design that is emulsifier-free and catalyst-free. Simultaneously, by using inexpensive pore-forming agent silica sol (i.e., aqueous silica solution) instead of the high-cost pore-forming agent polyacrylonitrile, the raw material cost is effectively reduced, overcoming the shortcomings of high cost and unfavorable scale-up in existing technologies. This provides a feasible path for the industrial application of millimeter-sized mesoporous carbon spheres in fixed-bed reactors, adsorption separation, and catalytic carriers.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The purpose of this invention is to provide a method for the large-scale preparation of millimeter-sized mesoporous carbon spheres, comprising the following steps: S1. Mix the aqueous solutions of phenolic precursors, aldehyde precursors, and silica to perform prepolymerization. During the prepolymerization process, the phenolic precursors in the aqueous solution of phenolic precursors and the aldehyde precursors in the aqueous solution of aldehyde precursors form a prepolymer, while the silica particles in the aqueous solution of silica encapsulate and embed in the prepolymer, thus obtaining a prepolymer solution.

[0007] S2. The prepolymer solution is added dropwise to the liquid paraffin oil. The prepolymer solution is dispersed in the liquid paraffin oil in the form of droplets and undergoes a reverse suspension polymerization reaction. During the reverse suspension polymerization reaction, the phenolic precursor and the aldehyde precursor continue to undergo a condensation reaction. The droplets change from a flowing liquid state to a solid phenolic resin. At this time, the silica particles are embedded in the phenolic resin. After aging treatment, phenolic resin balls are obtained.

[0008] S3. In an inert atmosphere, phenolic resin balls are calcined. During the calcination process, hydrogen and oxygen in the phenolic resin escape in the form of water molecules, leaving carbon skeleton and silicon dioxide particles, resulting in millimeter-sized carbon balls.

[0009] S4. The millimeter-sized carbon spheres are etched. During the etching process, the silica particles are etched and mesopores are formed, resulting in millimeter-sized mesoporous carbon spheres. The particle size of the millimeter-sized mesoporous carbon spheres is 0.5mm~2mm, the mesopore diameter is 5nm~30nm, and the specific surface area is 1000m². 2 / g~1200m 2 / g, pore volume 2cm 3 / g~3cm 3 / g.

[0010] Preferably, the mass ratio of phenolic precursor, aldehyde precursor and silica sol is 31:36:160~400, the mass fraction of silica in the silica aqueous solution is 30%, and the diameter of silica is 6nm~9nm.

[0011] Preferably, the mass-to-volume ratio of phenolic precursor to liquid paraffin oil is 165g:8L~20L.

[0012] Preferably, the phenolic precursor is selected from at least one of phenol, resorcinol, and aminophenol, and the aldehyde precursor in the aldehyde precursor solution is selected from at least one of formaldehyde, acetaldehyde, and furfural.

[0013] Preferably, the prepolymerization conditions are: stirring at 35°C to 50°C for 40 to 50 minutes.

[0014] Preferably, the specific operation of reverse suspension polymerization is as follows: the prepolymer solution is pumped into liquid paraffin oil at a feed rate of 300 mL / min to 750 mL / min through a nozzle of 0.8 mm to 1.0 mm, and stirred at a stirring rate of 310 rpm; wherein the number of nozzle holes is 18 to 36.

[0015] Preferably, the conditions for reverse suspension polymerization are: stirring at 70°C to 90°C at a stirring rate of 240 rpm to 310 rpm for 60 min to 80 min.

[0016] Preferably, the aging treatment conditions are: standing at 80°C~90°C for 24h~30h.

[0017] Preferably, the calcination conditions are as follows: heating to 800°C to 1100°C at a heating rate of 2°C / min to 10°C / min, and calcining for 3 to 5 hours.

[0018] Preferably, the inert atmosphere in the inert atmosphere is selected from N2, Ar, CO2 or Ne.

[0019] Preferably, alkali is used for etching, and the etching conditions are: stirring at 80°C~90°C for 3h~5h.

[0020] Preferably, the mass-to-volume ratio of millimeter-sized carbon balls to alkaline solution is 600g:8L~10L, and the mass percentage of alkaline solution is 15wt%~20wt%.

[0021] Preferably, a scale-up preparation system based on the above-described method for preparing millimeter-scale mesoporous carbon spheres includes: The prepolymer reactor has an inlet and an outlet, and the outlet of the prepolymer reactor is connected to the inlet of a peristaltic pump.

[0022] The solid-phase reactor has an inlet and an outlet. A nozzle is installed on the inlet. The outlet of the prepolymerization reactor is connected to the nozzle on the solid-phase reactor through a pipeline. A peristaltic pump is installed on the pipeline. A flange is connected to the outlet of the solid-phase reactor for discharging the solid phase from the reaction products. A vacuum pump is also connected to the bottom of the solid-phase reactor. A waste liquid tank is connected between the vacuum pump and the solid-phase reactor. The waste liquid in the waste liquid tank is filtered by the vacuum pump.

[0023] Both the prepolymer reactor and the solid reactor are equipped with stirring devices, and both are fixed on a support. The solid reactor is also connected to a condensation reflux device through a pipe for cooling the volatilized monomers.

[0024] The prepolymer solution is dispersed and dripped into the liquid paraffin oil in the solid reactor through the nozzle at a feed rate of 300 mL / min to 750 mL / min with an orifice diameter of 0.8 mm to 1.0 mm and 18 to 36 holes. The reverse suspension polymerization, aging treatment and etching treatment are completed under anchor or paddle stirring at 70℃ to 90℃ and 160 rpm to 310 rpm. Finally, millimeter-sized mesoporous carbon spheres with a diameter of 0.5 mm to 2 mm, regular spherical shape and smooth surface are obtained.

[0025] Preferably, the prepolymerization vessel is a high borosilicate glass vessel used to complete the prepolymerization of the precursor, and is equipped with a mechanical stirring device with a replaceable stirring paddle type.

[0026] Preferably, the solid reactor is a high borosilicate glass solid reactor, used to complete the molding, aging and etching processes of the prepolymer.

[0027] Preferably, both the prepolymerization reactor and the solid phase reactor are heated by a jacketed method. The jacket of the solid phase reactor is connected to the high and low temperature integrated machine, and the jacket of the prepolymerization reactor is connected to the oil bath.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a method for preparing millimeter-sized mesoporous carbon spheres. The method involves mixing an aqueous solution of a phenolic precursor, an aqueous solution of an aldehyde precursor, and an aqueous solution of silica for prepolymerization. During prepolymerization, the phenolic precursor in the aqueous phenolic precursor solution and the aldehyde precursor in the aqueous aldehyde precursor solution form a prepolymer, while silica particles in the aqueous silica solution coat and embed within the prepolymer, resulting in a prepolymer solution. The prepolymer solution is then dropwise added to liquid paraffin oil, where it is dispersed as droplets and subjected to a reverse suspension polymerization reaction. During the process, phenolic precursors and aldehyde precursors continue to undergo condensation reaction, and the droplets transform from a flowing liquid state to a solid phenolic resin. At this point, silica particles are embedded in the phenolic resin. After aging, phenolic resin spheres are obtained. In an inert atmosphere, the phenolic resin spheres are calcined. During the calcination process, hydrogen and oxygen elements in the phenolic resin escape in the form of water molecules, leaving a carbon skeleton and silica particles, resulting in millimeter-sized carbon spheres. The millimeter-sized carbon spheres are then etched. During the etching process, silica particles are etched away, forming mesopores, resulting in millimeter-sized mesoporous carbon spheres.

[0029] The present invention provides a method for the scale-up preparation of millimeter-sized mesoporous carbon spheres. In the pre-polymerization stage, only a carbon source (aqueous solutions of phenolic and aldehyde precursors) and a pore-forming agent (aqueous silica) are introduced, eliminating the need for emulsifiers and polymerization catalysts. Furthermore, the molding stage does not require the addition of expensive organic pore-forming agents, surfactants, or pH adjusters, thus obtaining millimeter-sized mesoporous carbon spheres with uniform shape, smooth surface, large specific surface area, and high porosity. The preparation method of this invention overcomes the synthesis uncertainties introduced by emulsifiers and polymerization catalysts; and by replacing the high-cost pore-forming agent polyacrylonitrile with the inexpensive pore-forming agent silica sol, it significantly reduces raw material costs and overcomes the problem of high polyacrylonitrile cost hindering scale-up production.

[0030] 2. This invention provides a model of a scaled-up preparation device for millimeter-scale mesoporous carbon spheres, filling a gap in the industry.

[0031] 3. The preparation method provided by this invention has simple steps, is easy to operate, and has low raw material costs, which is beneficial for cost control after large-scale production.

[0032] 4. The millimeter-sized mesoporous carbon spheres prepared by this invention are regularly spherical with smooth surfaces; their diameter is 0.5mm~2mm, the mesopore diameter is 5mm~30mm, and the specific surface area is 1000m². 2 / g~1200m 2 / g, pore volume 2cm 3 / g~3cm 3 / g. This structure endows millimeter-sized mesoporous carbon spheres with excellent adsorption capacity and diffusion efficiency, showing strong application prospects in the adsorption field; at the same time, its extremely high specific surface area and pore volume provide a sufficient interfacial platform for surface functionalization, active site anchoring, and gas-solid / gas-liquid-solid multiphase catalytic reactions. Attached Figure Description

[0033] Figure 1 Schematic diagram of a millimeter-scale mesoporous carbon sphere amplification device Figure 2 This is a photograph of the millimeter-sized mesoporous carbon spheres from Example 4.

[0034] Figure 3 The graph shows the nitrogen adsorption-desorption curves of the millimeter-sized mesoporous carbon spheres in Example 4.

[0035] Figure 4 This is a pore size distribution diagram of the millimeter-sized mesoporous carbon spheres in Example 4.

[0036] Explanation of reference numerals in the attached figures: 1. Prepolymer reactor, 11. Liquid inlet, 12. Liquid outlet, 3. Peristaltic pump, 31. Inlet, 32. Outlet, 4. Solid reactor, 41. Feed inlet, 42. Discharge outlet, 7. Vacuum pump, 8. Support. Detailed Implementation

[0037] The technical solution of the present invention will be clearly and completely described below with reference to the data in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0038] It should be noted that the technical terms used in this invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased on the market or prepared by existing methods.

[0039] In existing technologies, the preparation of millimeter-sized mesoporous carbon spheres generally relies on emulsifiers, polymerization catalysts, or high-cost precursors (such as polyacrylonitrile), resulting in complex synthesis processes, high costs, and poor batch stability, which is not conducive to large-scale application.

[0040] To address the problems of the existing technologies, this invention overcomes the synthesis uncertainties and post-processing complexities caused by the introduction of additives in traditional methods through a reverse suspension polymerization process without emulsifiers or polymerization catalysts. By replacing the high-cost raw material of polyacrylonitrile pore-forming agent with inexpensive silica sol (i.e., the silica aqueous solution in this invention), the bottleneck of high raw material costs and difficulty in industrial scale-up is solved, providing a technical foundation for the large-scale application of millimeter-sized mesoporous carbon spheres in catalysis, adsorption, and fixed-bed reactors.

[0041] To enable those skilled in the art to more clearly understand the technical solution of the present invention, the following will provide a detailed description in conjunction with specific embodiments: In the small-scale test, the effect of the prepolymer addition method on the molding of millimeter-sized mesoporous carbon spheres was investigated: Example 1 A method for preparing millimeter-sized mesoporous carbon spheres includes the following steps: S1, Prepolymerization of precursors: 45 mL of deionized water and 5 g of resorcinol were added to a 100 mL round-bottom flask. A magnetic stir bar was added, and the mixture was stirred at 250 rpm at 40°C until the resorcinol was completely dissolved, yielding a resorcinol aqueous solution. Subsequently, 5.45 g of formaldehyde aqueous solution and 36 g of silica sol were weighed and added to the resorcinol aqueous solution. Prepolymerization was carried out at 40°C, and the reaction was stirred for 40 min to obtain a prepolymer solution. The formaldehyde in the formaldehyde aqueous solution had a formaldehyde mass fraction of 37 wt%.

[0042] S2. Prepolymer molding and aging: 160 mL of paraffin oil was added to a 500 mL three-necked flask and stirred at 80°C using a stainless steel paddle at a stirring rate of 310 rpm. The prepolymer solution of S1 was dripped into the liquid paraffin by gravity through a 10 mL syringe with a 1 mm needle and subjected to reverse suspension polymerization at a stirring rate of 310 rpm for 1 h to obtain phenolic resin balls. The phenolic resin balls were then aged at 80°C for 24 h, the paraffin oil was filtered off, and the balls were washed twice with petroleum ether and once with 95% ethanol. Finally, the balls were dried at 80°C for 24 h to obtain phenolic resin balls.

[0043] S3, calcination of phenolic resin balls: Phenolic resin balls were placed in a quartz boat and heated to 800°C at a rate of 10°C / min under N2 conditions. The mixture was calcined for 3 hours and then allowed to cool naturally to obtain millimeter-sized carbon balls.

[0044] S4, Alkali treatment of millimeter-sized carbon spheres: 30g of NaOH and 170g of deionized water were added to a 500mL three-necked flask. Mechanical stirring was started, and the mixture was stirred at 80°C and a stirring rate of 240rpm to dissolve the NaOH solution, resulting in a 15wt% NaOH solution. Subsequently, 15g of millimeter-sized carbon spheres were added to the 500mL three-necked flask, and the reaction was continued at 80°C for 3 hours with stirring. After the reaction was completed, the mixture was filtered and washed until neutral, and then dried to obtain millimeter-sized mesoporous carbon spheres.

[0045] Example 2 A method for preparing millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 1, except that the 10mL syringe with a 1mm needle is replaced with a 20mL syringe with a 1.6mm needle.

[0046] Comparative Example 1 A method for preparing millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 1, except that the 10mL syringe with a 1mm needle is replaced with a 1mL syringe with a 0.6mm needle.

[0047] Comparative Example 2 A method for preparing millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 1, except that the 10mL syringe with a 1mm needle is replaced by directly pouring the precursor solution into the paraffin oil.

[0048] Example 3 A method for preparing millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 1, except that the 10mL syringe with a 1mm needle is replaced with a dropper used manually to add the spheres drop by drop into the paraffin oil.

[0049] The diameter distribution of millimeter-sized mesoporous carbon spheres prepared in Examples 1-3 and Comparative Examples 1-2 is shown in Table 1 below: Table 1 shows the effects of different prepolymer addition methods on the molding of millimeter-sized mesoporous carbon spheres in the small-scale test. For the scale-up preparation method of millimeter-sized mesoporous carbon spheres: The scale-up preparation system for millimeter-scale mesoporous carbon spheres provided by this invention comprises a core structure including a prepolymerization vessel 1, a peristaltic pump 3, a solid-state vessel 4, a vacuum pump 7, and a support 8, as shown below. Figure 1 As shown.

[0050] The prepolymer reactor 1 and the solid phase reactor 4 are fixed to the same operating platform by a support 8. The two are connected in sequence through a piping system to form a continuous production unit. The positional relationship and functional relationship of each component are as follows: The prepolymer reactor 1 is a high borosilicate glass reactor, fixed to the left side of the support 8. It has an inlet 11 at the top for adding raw materials such as phenolic precursors, aldehyde precursors, and silica aqueous solution, and an outlet 12 at the bottom side wall for discharging the prepolymer solution. The prepolymer reactor 1 adopts a jacketed heating structure to precisely control the prepolymerization temperature of 35°C to 50°C. It is equipped with a mechanical stirring device with replaceable stirring paddles to ensure that the materials are fully mixed and complete the prepolymerization reaction of the precursors.

[0051] The inlet 31 of the peristaltic pump 3 is tightly connected to the outlet 12 of the prepolymer reactor through a corrosion-resistant pipe, and the outlet 32 ​​of the peristaltic pump 3 is connected to the nozzle at the top of the solid reactor 4 through a pipe. Its function is to quantitatively deliver the prepolymer solution completed in the prepolymer reactor 1 to the solid reactor 4 at a stable flow rate of 300 mL / min to 750 mL / min, so as to realize the precise transfer and flow control of the prepolymer solution.

[0052] The solid reactor 4 is a high borosilicate glass reactor, fixed to the right side of the support 8. A feed inlet 41 is located at the center of its top, containing liquid paraffin oil as the dispersion medium. A nozzle is sealed at the feed inlet 41 of the solid reactor 4. The nozzle has an orifice diameter of 0.8mm~1.0mm and 18~36 holes. The outlet 32 ​​of the peristaltic pump 3 is connected to the nozzle, allowing the prepolymer solution to be dispersed into uniform droplets and enter the paraffin oil. The solid reactor 4 also employs a jacketed heating structure externally and is equipped with an anchor or paddle-type stirring device internally. This device can stir at a temperature of 70°C~90°C at a speed of 160rpm~310rpm to complete the three key processes of reverse suspension polymerization, aging treatment, and etching treatment. A discharge outlet 42 is located on the bottom side wall of the solid reactor 4, and a vacuum pump 7 is connected to the center of the bottom.

[0053] The flange is installed at the discharge port 42 of the solid reactor 4 to seal the discharge pipe. It can be opened after the reaction is completed to discharge the solid product (phenolic resin balls or carbon balls) and realize convenient material transfer.

[0054] Vacuum pump 7 is installed at the bottom of solid phase reactor 4 and is directly connected to the inside of solid phase reactor 4. It is used to quickly achieve solid-liquid separation after aging and etching treatment, effectively filter out liquid media such as paraffin oil, washing solvent and alkali solution, and shorten the production cycle.

[0055] The support frame 8 is a steel structure load-bearing frame that vertically fixes the prepolymer reactor 1 and the solid phase reactor 4 at a suitable operating height by means of clamps or bolts, ensuring that the entire system remains stable during stirring and pumping, and providing space for pipeline layout.

[0056] (1) Investigate the effect of phenolic precursors on the formation of millimeter-sized mesoporous carbon spheres: Example 4 A method for large-scale preparation of millimeter-sized mesoporous carbon spheres includes the following steps: S1. Add 1.5L of deionized water and 165g of resorcinol to a 5L glass reactor. Stir at 35°C and 350rpm until the resorcinol is completely dissolved to obtain a resorcinol aqueous solution. Then weigh 180g of formaldehyde aqueous solution and 1.2kg of silica sol, add them to the resorcinol aqueous solution, and carry out prepolymerization at 35°C. After stirring for 40min, a prepolymer solution is obtained. The formaldehyde in the formaldehyde aqueous solution has a formaldehyde mass fraction of 37wt%.

[0057] S2. Shaping and Aging: 8 L of paraffin oil was added to a glass reactor and stirred at 80°C using an anchor-type agitator at a stirring rate of 310 rpm to obtain liquid paraffin oil. The prepolymer solution of S1 was pumped into the liquid paraffin oil through a peristaltic pump at a feed rate of 400 mL / min and a 1 mm nozzle. The mixture was then subjected to reverse suspension polymerization at a stirring rate of 310 rpm for 1 h to obtain phenolic resin balls, wherein the nozzle had 18 orifices. The phenolic resin balls were then aged at 80°C for 24 h. The paraffin oil was filtered off, and the mixture was washed twice with petroleum ether and once with 95% ethanol. Finally, the mixture was dried at 80°C for 24 h to obtain phenolic resin balls.

[0058] S3. Place the phenolic resin balls in a quartz boat and calcine them to 800°C at a heating rate of 10°C / min under N2 conditions for 3 hours. Then allow them to cool naturally to obtain millimeter-sized carbon balls.

[0059] S4, Alkali Treatment: 1.2 kg of NaOH and 6.8 kg of deionized water were added to a 20 L glass reactor and stirred at 80°C with a stirring rate of 240 rpm to obtain a 15 wt% NaOH solution. Then, 600 g of millimeter-sized carbon spheres were added to the 20 L glass reactor and the reaction was continued at 80°C for 3 h with stirring. After the reaction was completed, the mixture was filtered and washed until neutral, and then dried to obtain millimeter-sized mesoporous carbon spheres.

[0060] Example 5 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the phenolic precursor is replaced by an equimolar amount of phenol instead of resorcinol.

[0061] Example 6 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the phenolic precursor is replaced by an equimolar amount of aminophenol instead of resorcinol.

[0062] The diameter distribution of the millimeter-sized mesoporous carbon spheres prepared in Examples 4 to 6 is shown in Table 2 below: Table 2 shows the effects of different phenolic precursors on the molding of millimeter-sized mesoporous carbon spheres. (2) The effect of aldehyde precursors on the molding of millimeter-sized mesoporous carbon spheres: Example 7 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the aldehyde precursor is replaced by an equimolar amount of furfural instead of formaldehyde.

[0063] Example 8 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the aldehyde precursor is replaced by an equimolar amount of acetaldehyde instead of formaldehyde.

[0064] The diameter distribution of the millimeter-sized mesoporous carbon spheres prepared in Examples 4 and 7-8 is shown in Table 3 below: Table 3 shows the effects of different aldehyde precursors on the molding of millimeter-sized mesoporous carbon spheres. (3) The effect of silica sol quality on the molding of millimeter-sized mesoporous carbon spheres: Example 9 A method for amplifying millimeter-scale mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the mass of silica sol is replaced from 1.2 kg to 0.8 kg.

[0065] Example 10 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the mass of silica sol is replaced by 2.0 kg instead of 1.2 kg.

[0066] The diameter distribution of the millimeter-sized mesoporous carbon spheres prepared in Examples 4 and 9-10 is shown in Table 4 below: Table 4 shows the effect of different silica sol addition masses on the molding of millimeter-sized mesoporous carbon spheres. (4) Effect of prepolymerization temperature on the molding of millimeter-sized mesoporous carbon spheres: Comparative Example 3 A method for the scaled-up preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the prepolymerization temperature is replaced by 10°C instead of 35°C.

[0067] Example 11 A method for the scaled-up preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the prepolymerization temperature is replaced by 50°C instead of 35°C.

[0068] Comparative Example 4 A method for the scaled-up preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the prepolymerization temperature is replaced by 80°C instead of 35°C.

[0069] The diameter distribution of millimeter-sized mesoporous carbon spheres prepared in Examples 4, 11, and Comparative Examples 3 to 4 is shown in Table 5 below: Table 5 shows the effect of different prepolymerization temperatures on the molding of millimeter-sized mesoporous carbon spheres. (5) Effect of prepolymerization temperature on the molding of millimeter-sized mesoporous carbon spheres: Comparative Example 5 A method for the scaled-up preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the prepolymerization time is replaced by 10 min instead of 40 min.

[0070] Example 12 A method for the scaled-up preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the prepolymerization time is changed from 40 min to 50 min.

[0071] Comparative Example 6 A method for the scaled-up preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the prepolymerization time is replaced by 80 min instead of 40 min.

[0072] The diameter distribution of millimeter-sized mesoporous carbon spheres prepared in Examples 4, 12, and Comparative Examples 5 to 6 is shown in Table 6 below: Table 6 shows the effect of prepolymerization temperature on the molding of millimeter-sized mesoporous carbon spheres. (6) Effects of molding temperature and time on the molding of millimeter-sized mesoporous carbon spheres: Example 13 A method for the scaled-up preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the reverse suspension polymerization time is replaced by 240 min instead of 60 min.

[0073] Example 14 A method for the scaled-up preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the reverse suspension polymerization time is replaced by 360 min instead of 60 min.

[0074] Comparative Example 7 A method for the scaled-up preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the temperature of the reverse suspension polymerization is replaced by 40°C instead of 80°C.

[0075] Comparative Example 8 A method for the scaled-up preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the temperature of the reverse suspension polymerization is replaced by 120°C instead of 80°C.

[0076] Example 15 A method for the scaled-up preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the temperature of the reverse suspension polymerization is replaced by 90°C instead of 80°C.

[0077] The diameter distribution of millimeter-sized mesoporous carbon spheres prepared in Examples 4, 13-15, and Comparative Examples 7-8 is shown in Table 7 below: Table 7 shows the effects of different reverse suspension polymerization temperatures and times on the molding of millimeter-sized mesoporous carbon spheres. (7) The effect of mechanical stirring rate and stirring paddle type on the molding of millimeter-sized mesoporous carbon balls during the molding process: Example 16 A method for the scaled-up preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the stirring rate of the reverse suspension polymerization is replaced by 160 rpm instead of 310 rpm.

[0078] Example 17 A method for the scaled-up preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the stirring rate of the reverse suspension polymerization is replaced by 250 rpm instead of 310 rpm.

[0079] Comparative Example 9 A method for the scaled-up preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the stirring rate of the reverse suspension polymerization is replaced by 350 rpm instead of 310 rpm.

[0080] Example 18 A method for the scaled-up preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the type of stirring paddle for reverse suspension polymerization is changed from anchor type to paddle type.

[0081] Example 19 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the type of agitator for reverse suspension polymerization is changed from anchor type to propeller type.

[0082] The diameter distribution of millimeter-sized mesoporous carbon spheres prepared in Examples 4, 16-19, and Comparative Example 9 is shown in Table 8 below: Table 8 shows the effect of different mechanical stirring rates on the formation of millimeter-sized mesoporous carbon spheres during the polymerization process. (8) Effects of aging temperature and time on the molding of millimeter-sized mesoporous carbon spheres: Example 20 A method for amplifying millimeter-scale mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the aging time is changed from 24 min to 72 min.

[0083] Comparative Example 10 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the aging time is replaced by 10 hours instead of 24 hours.

[0084] Example 21 A method for amplifying millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the aging temperature is replaced by 40°C instead of 80°C and the aging time is replaced by 72h instead of 24h.

[0085] Comparative Example 11 A method for amplifying millimeter-scale mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the aging temperature is replaced by 40°C instead of 80°C.

[0086] Comparative Example 12 A method for amplifying millimeter-scale mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the aging temperature is replaced by 120°C instead of 80°C.

[0087] Example 22 A method for amplifying millimeter-scale mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the aging temperature is replaced by 90°C instead of 80°C.

[0088] The diameter distribution of millimeter-sized mesoporous carbon spheres prepared in Examples 4, 20-22, and Comparative Examples 10-12 is shown in Table 9 below: Table 9 shows the effects of different aging temperatures and times on the molding of millimeter-sized mesoporous carbon spheres. (9) The effect of paraffin oil addition during molding on the molding of millimeter-sized mesoporous carbon spheres: Comparative Example 13 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the volume of paraffin oil is replaced from 8L to 4L.

[0089] Example 23 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the volume of paraffin oil is replaced from 8L to 10L.

[0090] Example 24 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the volume of paraffin oil is replaced from 8L to 20L.

[0091] The diameter distribution of millimeter-sized mesoporous carbon spheres prepared in Examples 4, 23-24, and Comparative Example 13 is shown in Table 10 below: Table 10 shows the effect of different paraffin oil addition amounts on the molding of millimeter-sized mesoporous carbon spheres. (10) The effects of nozzle diameter, number of holes and feed rate on the formation of millimeter-sized mesoporous carbon spheres during stirred polymerization: Example 25 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the nozzle diameter in the stirring polymerization process is replaced with 0.8 mm instead of 1 mm, and the feed rate is replaced with 300 mL / min instead of 400 mL / min.

[0092] Comparative Example 14 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the nozzle diameter in the stirring polymerization process is replaced with 0.4 mm instead of 1 mm, and the feed rate is replaced with 250 mL / min instead of 400 mL / min.

[0093] Example 26 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the nozzle diameter in the stirring polymerization process is replaced with 1.5 mm instead of 1 mm, and the feed rate is replaced with 550 mL / min instead of 400 mL / min.

[0094] Example 27 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the number of nozzle holes in the stirring polymerization process is replaced with 36 instead of 18.

[0095] Example 28 A method for the scaled-up preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the feed rate during the stirring polymerization process is replaced by 750 mL / min instead of 400 mL / min.

[0096] The diameter distribution of millimeter-sized mesoporous carbon spheres prepared in Examples 4, 25-28, and Comparative Example 14 is shown in Table 11 below: Table 11 shows the results of the influence of nozzle diameter and feed rate on the molding of millimeter-sized mesoporous carbon spheres during the molding process. (11) The effect of calcination process on the formation of millimeter-sized mesoporous carbon spheres: Example 29 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the heating rate during calcination is replaced by 2°C / min instead of 10°C / min.

[0097] Example 30 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the calcination temperature in the calcination process is replaced by 1100°C instead of 800°C.

[0098] Example 31 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the calcination time in the calcination process is replaced by 5 hours instead of 3 hours.

[0099] Example 32 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the calcination atmosphere during the calcination process is replaced with Ar instead of N2.

[0100] Example 33 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the calcination atmosphere during the calcination process is replaced with CO2 instead of N2.

[0101] Example 34 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the calcination atmosphere during the calcination process is replaced with Ne instead of N2.

[0102] The diameter distribution of millimeter-sized mesoporous carbon spheres prepared in Examples 4, 29-34 is shown in Table 12 below: Table 12 shows the results of the effect of the calcination process on the formation of millimeter-sized mesoporous carbon spheres. (12) The effect of alkali treatment on the formation of millimeter-sized mesoporous carbon spheres: Comparative Example 15 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the mass fraction of NaOH solution in the S4 alkali treatment process is replaced from 15wt% to 5wt%.

[0103] Example 35 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the mass fraction of NaOH solution in the S4 alkali treatment process is replaced by 20 wt% instead of 15 wt%.

[0104] Comparative Example 16 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the volume of NaOH solution is replaced with 5L during the S4 alkali treatment process instead of 8L.

[0105] Example 36 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the volume of NaOH solution is changed from 8L to 10L during the S4 alkali treatment process.

[0106] Comparative Example 17 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the reaction temperature is changed from 80°C to 60°C during the S4 alkali treatment process.

[0107] Example 37 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the reaction temperature is changed from 80°C to 90°C during the S4 alkali treatment process.

[0108] Comparative Example 18 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the stirring time during the S4 alkali treatment is changed from 3h to 1.5h.

[0109] Example 38 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that the stirring time during the S4 alkali treatment is changed from 3 hours to 5 hours.

[0110] Example 39 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that NaOH is replaced with KOH in the S4 alkali treatment process.

[0111] Example 40 A method for the large-scale preparation of millimeter-sized mesoporous carbon spheres is the same as the preparation steps in Example 4, except that NaOH is replaced with a mixture of KOH and NaOH in the S4 alkali treatment process; wherein the mass ratio of KOH to NaOH is 1:1.

[0112] The diameter distribution of millimeter-sized mesoporous carbon spheres prepared in Examples 4, 35-40, and Comparative Examples 15-18 is shown in Table 13 below. Among them, those with a mass loss of less than 80% do not meet the requirements of the preparation process.

[0113] Table 13 shows the results of the effect of alkaline treatment on the formation of millimeter-sized mesoporous carbon spheres. The millimeter-sized mesoporous carbon spheres prepared in Example 4 were characterized and their structure was evaluated. The results are as follows: from Figure 2 It is found that the millimeter-sized mesoporous carbon spheres prepared by this invention are spherical with smooth surfaces and uniform distribution.

[0114] like Figure 3 As shown, the nitrogen adsorption-desorption curve of the millimeter-sized mesoporous carbon spheres in Example 4 exhibited a hysteresis loop at a relative pressure (P / P0) of 0.5–1.0, indicating that they possess a classic mesoporous structure. Furthermore, the test results show that their specific surface area is 1118.2556 m². 2 / g, pore volume is 2.757cm³ 3 / g.

[0115] from Figure 4 It was found that the millimeter-sized mesoporous carbon spheres of Example 4 were mainly mesoporous with an average pore size of 11.47 nm.

[0116] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

Claims

1. A method for preparing millimeter-sized mesoporous carbon spheres, characterized in that, Includes the following steps: Aqueous solutions of phenolic precursors, aldehydes, and silica were mixed and prepolymerized. During the prepolymerization process, the phenolic precursors in the aqueous solution and the aldehydes in the aqueous solution formed a prepolymer, while silica particles in the aqueous solution coated and embedded in the prepolymer, thus obtaining a prepolymer solution. The prepolymer solution is added dropwise to liquid paraffin oil, and the prepolymer solution is dispersed in the liquid paraffin oil in the form of droplets to carry out a reverse suspension polymerization reaction. During the reverse suspension polymerization reaction, the phenolic precursor and the aldehyde precursor continue to undergo a condensation reaction, and the droplets change from a flowing liquid state to a solid phenolic resin. At this time, the silica particles are embedded in the phenolic resin. After aging treatment, phenolic resin balls are obtained. In an inert atmosphere, phenolic resin balls are calcined. During the calcination process, hydrogen and oxygen in the phenolic resin escape in the form of water molecules, leaving a carbon skeleton and silica particles, resulting in millimeter-sized carbon balls. Millimeter-sized carbon spheres are etched. During the etching process, silicon dioxide particles are etched and mesopores are formed, resulting in millimeter-sized mesoporous carbon spheres. The millimeter-sized mesoporous carbon spheres have a particle size of 0.5 mm to 2 mm, a mesopore size of 5 nm to 30 nm, and a specific surface area of ​​1000 m². 2 / g~1200m 2 / g, pore volume 2cm 3 / g~3cm 3 / g.

2. The method for preparing millimeter-sized mesoporous carbon spheres according to claim 1, characterized in that, The mass ratio of phenolic precursors, aldehyde precursors and silica aqueous solution is 31:36:160~400, and the mass fraction of silica in the silica aqueous solution is 30%.

3. The method for preparing millimeter-scale mesoporous carbon spheres according to claim 1, characterized in that, The mass-to-volume ratio of phenolic precursor to liquid paraffin oil is 165g:8L~20L.

4. The method for preparing millimeter-sized mesoporous carbon spheres according to claim 1, characterized in that, The prepolymerization conditions are: stirring at 35°C to 50°C for 40 to 50 minutes.

5. The method for preparing millimeter-scale mesoporous carbon spheres according to claim 1, characterized in that, The conditions for reverse suspension polymerization are: stirring at 40°C to 90°C for 60 min to 360 min at a stirring rate of 160 rpm to 310 rpm.

6. The method for preparing millimeter-scale mesoporous carbon spheres according to claim 1, characterized in that, The aging conditions are: standing at 80°C~90°C for 24h~72h.

7. The method for preparing millimeter-scale mesoporous carbon spheres according to claim 1, characterized in that, The calcination conditions are: calcination at 800°C~1100°C for 3h~5h.

8. The method for preparing millimeter-scale mesoporous carbon spheres according to claim 1, characterized in that, The millimeter-sized carbon spheres were etched using an alkaline solution. The mass-to-volume ratio of the millimeter-sized carbon spheres to the alkaline solution was 600g:8L~10L, and the mass percentage of the alkaline solution was 15wt%~20wt%.

9. The method for preparing millimeter-scale mesoporous carbon spheres according to claim 8, characterized in that, Alkali etching is performed under the following conditions: the alkaline solution is mixed with millimeter-sized carbon balls and stirred at 80°C to 90°C for 3 to 5 hours.

10. A scale-up preparation system based on the preparation method of millimeter-scale mesoporous carbon spheres according to any one of claims 1 to 9, characterized in that, include: The prepolymer reactor (1) has an inlet (11) and an outlet (12). The solid reactor (4) has an inlet (41) and an outlet (42). The inlet (41) is equipped with a nozzle. The outlet (12) of the prepolymer reactor (1) is connected to the nozzle on the solid reactor (4) through a pipeline. The peristaltic pump (3) is installed on the pipeline. The outlet (42) of the solid reactor (4) is connected with a flange for discharging the solid phase in the reaction product. Both the prepolymer reactor (1) and the solid phase reactor (4) are equipped with stirring devices, and both the prepolymer reactor (1) and the solid phase reactor (4) are fixed on the support (8).

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