A method and device for preparing ultrafine porous activated carbon based on carbon nanotube circulation

Abstract

The present invention provides a preparation scheme of ultrafine porous activated carbon based on carbon nanotube circulation, including arranging an activated fluidized bed and a heated fluidized bed connected by a pipeline, filling an activated carbon precursor in the activated fluidized bed, and then filling the carbon nanotubes in the heated fluidized bed and passing them into the activated fluidized bed to heat the activated carbon precursor, reacting under the action of an activating medium, and obtaining an ultrafine porous activated carbon with a particle size of 1-10 microns. The present invention prepares ultrafine porous activated carbon based on carbon nanotube circulation, simplifies the structural design of the activated fluidized bed, and makes the reaction raw materials easy to process, avoiding the specific surface area and pore volume loss caused by the grinding and crushing of the activated carbon product. In addition, the heat transfer effect of carbon nanotubes is good, the stability is high, the reaction efficiency can be improved, and the product is continuous, large-scale and low-cost preparation is realized. The used carbon nanotubes can be used as an efficient adsorbent for organic waste, avoiding waste of resources.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of electrochemical energy storage electrode materials, and particularly to a preparation method and device for ultrafine porous activated carbon based on carbon nanotube recycling. Background Art

[0002] Devices based on clean electrochemical energy storage mechanisms, such as various secondary batteries, supercapacitors, lithium-ion capacitors or their hybrid devices, are important electrical energy storage systems and have developed rapidly in recent years. The positive electrode materials of supercapacitors and lithium-ion capacitors are porous activated carbon with a large specific surface area. Secondary batteries such as lithium-ion negative electrode materials (silicon-carbon negative electrodes) also use porous activated carbon with a large specific surface area as a fixed carrier for silicon particles, accounting for about 50% of the weight of the silicon-carbon negative electrode.

[0003] Due to the requirements of electrode sheet coating and to avoid serious electron polarization and ion polarization problems, the thickness of electrode sheets composed of these electrode materials is generally in the range of dozens of micrometers to 150 micrometers. This requires that the particle size of these carbon electrode materials is often 5-6 micrometers, which can not only ensure rapid ion transport but also have a relatively large packing density and corresponding electrode sheet compaction density.

[0004] Particles with a size of 5-6 micrometers belong to the range of ultrafine powders and have the characteristics of a large external specific surface area, serious aggregation, poor fluidity, and difficulty in direct processing. Therefore, in industry, large-particle activated carbon is often prepared by activation first and then ground into particles with a size of 5-6 micrometers. First, when large-particle activated carbon is activated, internal diffusion is serious, the reaction time is long, and the energy consumption is high. Second, 20-30% of the specific surface area and pore volume are lost during grinding, and at the same time, a large number of fine particles with a diameter of less than 5 micrometers are generated, resulting in product quality loss and high product cost. These problems currently exist in electrode carbon in several industries and have not been well solved. Summary of the Invention

[0005] In view of the above problems existing in the prior art, the present invention discloses a preparation method for ultrafine porous activated carbon based on carbon nanotube recycling, including:

[0006] Filling an activated carbon precursor into an activation fluidized bed and filling carbon nanotubes into a heating fluidized bed; after heating the carbon nanotubes to a temperature of 880-1000 °C in the heating fluidized bed, introducing them into the activation fluidized bed and heating the activated carbon precursor to a temperature of 800-950 °C;

[0007] Introducing nitrogen and an activation medium from the bottom of the fluidized bed to make the heated activated carbon precursor in a fluidized state under the action of the gas flow; after etching and pore formation of the heated activated carbon precursor by the activation medium for 1-10 h, discharging the obtained ultrafine porous activated carbon through a product outlet;

[0008] The carbon nanotubes circulate in the activation fluidized bed and the heating fluidized bed to keep the bed pressure drop and temperature in the activation fluidized bed 1 constant.

[0009] Optionally, the circulation time of the carbon nanotubes is 3 days. When the ultrafine porous activated carbon is discharged through the product outlet, the circulation of the carbon nanotubes is paused;

[0010] After the ultrafine porous activated carbon is discharged through the product outlet, a new batch of activated carbon precursors is added to the activation fluidized bed, and then the circulation of the carbon nanotubes is continued;

[0011] When the circulation time of the carbon nanotubes exceeds 3 days, they are exported and used as an efficient adsorbent for organic waste.

[0012] Optionally, the particle size of the activated carbon precursor is 1 - 10 microns; the bulk density of the activated carbon precursor is 0.3 - 0.8 g / mL;

[0013] The activated carbon precursor is a biomass or an artificial polymer; the biomass is one or more of coconut shell, apricot shell, plant starch, and lignin; the artificial polymer is one or more of phenolic resin, furan resin, and polyacrylonitrile pre-oxide.

[0014] Optionally, the carbon nanotubes are formed by curling 10 - 100 carbon layers; the bulk density of the carbon nanotubes is 0.05 - 0.1 g / mL; the outer diameter of the carbon nanotubes is 8 - 80 nm; the aspect ratio of the carbon nanotubes is greater than 200.

[0015] Optionally, in the activation fluidized bed, the volume ratio of the carbon nanotubes to the activated carbon precursor is 0.3 - 1.5.

[0016] Optionally, the heating method of the heating fluidized bed is heating by introducing high-temperature gas flow or electric heating.

[0017] Optionally, the activation medium is one or both of carbon dioxide and water vapor; the flow rate of the activation medium is 0.05 - 0.2 m / s.

[0018] Optionally, the particle size of the ultrafine porous activated carbon is 1 - 10 microns; the specific surface area of the ultrafine porous activated carbon is 1500 - 2500 m 2 / g; the pore volume of the ultrafine porous activated carbon is 0.5 - 2.5 mL / g.

[0019] To solve the above problems, the present invention also discloses a preparation device for ultrafine porous activated carbon based on carbon nanotube circulation. The device includes an activation fluidized bed for reacting an activated carbon precursor under the action of carbon nanotubes and an activation medium to obtain ultrafine porous activated carbon.

[0020] A heating fluidized bed connected to the activation fluidized bed for heating the carbon nanotubes in the heating fluidized bed.

[0021] The carbon nanotubes circulate between the activation fluidized bed and the heating fluidized bed through a pipeline.

[0022] Optionally, a heat exchange tube or an electric heating rod is arranged in the heating fluidized bed to heat the carbon nanotubes in the heating fluidized bed. The heat exchange tube heats the carbon nanotubes in the heating fluidized bed through the high-temperature gas flow inside the tube.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] A preparation scheme for ultrafine porous activated carbon based on carbon nanotube circulation provided by an embodiment of the present application includes arranging an activation fluidized bed and a heating fluidized bed connected by a pipeline, filling the activated carbon precursor in the activation fluidized bed, and then filling the carbon nanotubes in the heating fluidized bed, heating them and introducing them into the activation fluidized bed to heat the activated carbon precursor, and reacting under the action of an activation medium to obtain ultrafine porous activated carbon with a particle size of 1-10 microns. During the reaction process, the carbon nanotubes circulate between the activation fluidized bed and the heating fluidized bed to keep the bed pressure drop and temperature in the activation fluidized bed constant. The present invention prepares ultrafine porous activated carbon based on carbon nanotube circulation, and the nanoscale carbon nanotubes contact with the micron-scale activated carbon precursor to assist the smooth fluidization and efficient activation of the activated carbon precursor, simplify the structural design of the activation fluidized bed, and make the activated carbon precursor easy to process.

[0025] Moreover, as a solid, carbon nanotubes have the advantages of large heat capacity, uniform mixing, and fast heat transfer. Compared with the pure gas heating in the traditional rotary furnace activation of small particle precursors technology, it not only ensures the heat supply of the reaction system, but also shortens the preparation time by 15%, reduces the gas cost by 50-60%, and improves the product consistency by 30%. In addition, since the diameter of carbon nanotubes is smaller than that of ultrafine porous activated carbon, they have good fluidity and high stability. During the whole preparation process, the structure of carbon nanotubes will not be damaged. The specific surface area of the carbon nanotubes after being unloaded at the end of the service time is increased by 10-20% compared with that before use, and the surface functional group density is increased by 30%-70%. They can be used as efficient adsorbents for organic waste, avoiding resource waste.

[0026] Compared with conventional preparation methods (such as first preparing large-particle activated carbon products and then grinding and pulverizing them; or using a Slep furnace to prepare porous activated carbon with a large specific surface area and a particle size in the millimeter range), the ultrafine porous activated carbon directly prepared in the present invention is in the micron range, so there is no need for subsequent grinding and pulverizing, effectively avoiding the risk of impurities introduced by grinding. Moreover, the yield is increased by 30%, the number of preparation devices is reduced by 20%, the equipment investment cost is reduced by 25 - 30%, and the time cost is saved by 50 - 80%. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of 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 some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0028] Figure 1 FIG. shows the flowchart of the preparation method of ultrafine porous activated carbon based on carbon nanotube circulation provided by the embodiment of the present invention;

[0029] Figure 2 FIG. shows the structural diagram of the preparation device of ultrafine porous activated carbon based on carbon nanotube circulation provided by the embodiment of the present invention.

[0030] DESCRIPTION OF THE REFERENCE NUMERALS

[0031] 1 - activation fluidized bed, 2 - heating fluidized bed, 3 - activation gas inlet, 4 - activation tail gas outlet, 5 - activated carbon precursor inlet, 6 - heat-carrying carbon nanotube inlet, 7 - circulating carbon nanotube outlet, 8 - circulating carbon nanotube inlet, 9 - heat-carrying carbon nanotube outlet, 10 - fluidizing gas inlet, 11 - fluidizing gas outlet, 12 - carbon nanotube inlet, 13 - heat exchange tube or heating rod, 14 - activated carbon product outlet, 15 - carbon nanotube product outlet. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all of them. The description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior art features falls within the protection scope of the present invention. And all other embodiments obtained by those of ordinary skill in the art without creative efforts also belong to the protection scope of the present invention.

[0033] In the prior art, when preparing ultrafine porous activated carbon with a particle size of 5-6 μm by using a fluidized bed, since particles with a size of 5-6 μm belong to ultrafine powder and are not easy to directly process and prepare, a method of first activating to prepare large-particle-size activated carbon and then grinding it to 5-6 μm is generally adopted. However, when large-particle-size particles are activated, internal diffusion is serious, the reaction time is long, and the energy consumption is high. Moreover, grinding will cause the product to lose 20-30% of the specific surface area and pore volume, and at the same time generate a large number of fine particles with a diameter of less than 5 μm, resulting in product quality loss and high costs. The embodiments of the present invention provide a preparation method and device for ultrafine porous activated carbon based on carbon nanotube circulation. The activated carbon precursor is filled in the activation fluidized bed 1, and then the carbon nanotubes are filled in the heating fluidized bed 2, heated and introduced into the activation fluidized bed 1 to heat the activated carbon precursor. The heated activated carbon precursor reacts under the action of the activation medium to obtain ultrafine porous activated carbon with a particle size of 1-10 μm. During the reaction process, the carbon nanotubes circulate in the activation fluidized bed 1 and the heating fluidized bed 2 to keep the bed pressure drop and temperature in the activation fluidized bed 1 constant. The specific implementation manner is as follows:

[0034] In a first aspect, the embodiments of the present invention provide a preparation method for ultrafine porous activated carbon based on carbon nanotube circulation, Figure 1 which shows the flow chart of the preparation method for ultrafine porous activated carbon based on carbon nanotube circulation provided by the embodiments of the present invention. As Figure 1 shown, it includes:

[0035] Filling the activated carbon precursor into the activation fluidized bed 1 and filling the carbon nanotubes into the heating fluidized bed 2; after heating the carbon nanotubes to a temperature of 880-1000 °C by the heating fluidized bed 2, introducing them into the activation fluidized bed 1 and heating the activated carbon precursor to a temperature of 800-950 °C;

[0036] In specific implementation, the activated fluidized bed 1 and the heating fluidized bed 2 are connected by pipelines to form a complete system. Activated carbon precursors with a particle size of 1 - 10 microns and a bulk density of 0.3 - 0.8 g / mL are filled into the activated fluidized bed 1 through the activated carbon precursor inlet 5. Carbon nanotubes with an outer diameter of 8 - 80 nm, an aspect ratio greater than 200, and a bulk density of 0.05 - 0.1 g / ml are filled into the heating fluidized bed 2 through the carbon nanotube inlet 12. The fluidizing gas (such as nitrogen) is introduced into the heating fluidized bed 2 through the fluidizing gas inlet 10 to make the carbon nanotubes in a fluidized state under the action of the gas flow. The carbon nanotubes are heated to a temperature of 880 - 1000 °C in the heating fluidized bed 2, and the heated carbon nanotubes are successively introduced into the activated fluidized bed 1 through the heat-carrying carbon nanotube outlet 9 and the heat-carrying carbon nanotube inlet 6 to indirectly heat the activated carbon precursors to a temperature of 800 - 950 °C. The activated carbon precursors are biomass or artificial polymers. The biomass is one or more of coconut shell, apricot shell, plant starch, and lignin. The artificial polymers are one or more of phenolic resin, furan resin, and polyacrylonitrile pre-oxide. The carbon nanotubes are formed by curling 10 - 100 carbon layers. The volume ratio of the carbon nanotubes to the activated carbon precursors is 0.3 - 1.5. The heating fluidized bed 2 heats the carbon nanotubes by introducing high-temperature gas flow or by electric heating.

[0037] Nitrogen and the activation medium are introduced from the bottom of the fluidized bed 1 to make the heated activated carbon precursors in a fluidized state under the action of the gas flow. After the activation medium etches and creates pores in the heated activated carbon precursors for 1 - 10 h, the obtained ultrafine porous activated carbon is discharged through the product outlet.

[0038] In specific implementation, nitrogen is introduced into the activated fluidized bed 1 through the activation gas inlet 3 to make the heated activated carbon precursors in a fluidized state under the action of the gas flow. The activation medium is introduced into the activated fluidized bed 1 through the activation gas inlet 3 to etch and create pores in the activated carbon precursors heated to a temperature of 800 - 950 °C for 1 - 10 h, and then the ultrafine porous activated carbon is obtained. The ultrafine porous activated carbon is discharged through the activated carbon product outlet 14 and cooled for standby. The activation tail gas is discharged from the activated fluidized bed 1 through the activation tail gas outlet 4. The activation medium is one or both of carbon dioxide and water vapor. The flow rate of the activation medium is 0.05 - 0.2 m / s. The particle size of the ultrafine porous activated carbon is 1 - 10 microns. The specific surface area of the ultrafine porous activated carbon is 1500 - 2500 m 2 / g. The pore volume of the ultrafine porous activated carbon is 0.5 - 2.5 mL / g.

[0039] The carbon nanotubes circulate in the activated fluidized bed 1 and the heating fluidized bed 2 to keep the bed pressure drop and temperature in the activated fluidized bed 1 constant.

[0040] In specific implementation, since carbon nanotubes have a smaller packing density compared to the activated carbon precursor, during the entire preparation process, the carbon nanotubes continuously move upward in the activation fluidized bed 1, return to the heating fluidized bed 2 through the circulating carbon nanotube outlet 7, pipeline and circulating carbon nanotube inlet 8, are heated, and then return to the activation fluidized bed 1 to heat the activated carbon precursor. The carbon nanotubes in the entire preparation process circulate in the activation fluidized bed 1 and the heating fluidized bed 2 to keep the bed pressure drop and temperature in the activation fluidized bed 1 constant; when the obtained ultrafine porous activated carbon is discharged through the activated carbon product outlet 14, the supply of heated carbon nanotubes to the activation fluidized bed 1 is stopped to suspend the circulating flow of the carbon nanotubes; after the ultrafine porous activated carbon is discharged through the activated carbon product outlet 14, a new batch of activated carbon precursors is added to the activation fluidized bed 1, and then heated carbon nanotubes are continuously supplied to the activation fluidized bed 1 to resume the circulating flow of the carbon nanotubes, and the above preparation process is repeated; the circulating flow time of the carbon nanotubes in the entire reaction system is controlled to be 3 days to obtain carbon nanotube products, which are discharged through the carbon nanotube product outlet 15, collected. The specific surface area of the collected carbon nanotube products is increased by 10 - 20% compared to the carbon nanotubes before use, and the surface functional group density is increased by 30 - 70%, and they can be used as high-efficiency adsorbents for organic waste; a new batch of carbon nanotubes is added to the heating fluidized bed 2 to continue the circulating flow for the next cycle of 3 days;

[0041] In a second aspect, the present invention provides a preparation device for ultrafine porous activated carbon based on the circulation of carbon nanotubes, Figure 2 which shows the structural diagram of the preparation device for ultrafine porous activated carbon based on the circulation of carbon nanotubes provided by the embodiment of the present invention, as Figure 2 shown. The device includes an activation fluidized bed 1, which is used to react the activated carbon precursor under the action of carbon nanotubes and an activation medium to obtain ultrafine porous activated carbon; a heating fluidized bed 2 connected to the activation fluidized bed 1, which is used to heat the carbon nanotubes in the heating fluidized bed 2; the carbon nanotubes circulate between the activation fluidized bed 1 and the heating fluidized bed 2 through a pipeline; a heat exchange tube or an electric heating rod 13 is arranged in the heating fluidized bed 2 to realize heating of the carbon nanotubes in the heating fluidized bed 2; the heat exchange tube 13 heats the carbon nanotubes in the heating fluidized bed 2 through the high-temperature gas flow inside the tube.

[0042] A preparation scheme of ultrafine porous activated carbon based on carbon nanotube circulation provided by this application. The activated carbon precursor is filled in the activation fluidized bed 1, and then the carbon nanotubes are filled in the heating fluidized bed 2. After heating, the carbon nanotubes are introduced into the activation fluidized bed 1 to heat the activated carbon precursor. The activated carbon precursor reacts under the action of the activation medium to obtain ultrafine porous activated carbon with a particle size of 1-10 microns. During the reaction process, the carbon nanotubes circulate in the activation fluidized bed 1 and the heating fluidized bed 2 to keep the bed pressure drop and temperature in the activation fluidized bed 1 constant. This invention prepares ultrafine porous activated carbon based on carbon nanotube circulation, simplifies the structural design of the activation fluidized bed, makes the reaction raw materials easy to process, avoids the risks of impurity doping, specific surface area and pore volume loss caused by grinding and crushing of the activated carbon product, and reduces the time cost and economic cost of the preparation process. In addition, the carbon nanotubes have good heat transfer effect and high stability, can improve the reaction efficiency, and realize the continuous, large-scale and low-cost preparation of products; as a solid heating medium, the carbon nanotubes can improve the product consistency compared with the gas heating medium; the used carbon nanotubes can be used as an efficient adsorbent for organic waste, avoiding waste of resources.

[0043] To enable those skilled in the art to understand the present invention more clearly, the following examples are now used to describe in detail a preparation method and device of ultrafine porous activated carbon based on carbon nanotube circulation described in the present invention.

[0044] Example 1

[0045] (1) Connect the activation fluidized bed 1 and the heating fluidized bed 2 with pipelines to form a complete system; fill the activated carbon precursor (biomass, coconut shell) with a particle size of 1-10 microns and a bulk density of 0.3-0.8 g / mL into the activation fluidized bed 1 through the activated carbon precursor inlet 5, and then fill the carbon nanotubes formed by curling 10-100 carbon layers with an outer diameter of 8-80 nm, an aspect ratio greater than 200, and a bulk density of 0.05-0.1 g / ml into the heating fluidized bed 2 through the carbon nanotube inlet 12; introduce the fluidizing gas (nitrogen) into the heating fluidized bed 2 through the fluidizing gas inlet 10 to make the carbon nanotubes in a fluidized state under the action of the air flow;

[0046] (2) By introducing high-temperature gas into the heat exchange tubes 13 in the heated fluidized bed 2, the carbon nanotubes are heated to a temperature of 900 °C. The heated carbon nanotubes are successively introduced into the activation fluidized bed 1 through the heat-carrying carbon nanotube outlet 9, pipeline, and heat-carrying carbon nanotube inlet 6, indirectly heating the activated carbon precursor to a temperature of 850 - 880 °C; in the activation fluidized bed 1, the volume ratio of carbon nanotubes to the activated carbon precursor is maintained at 0.4 - 0.5; during the entire preparation process, the carbon nanotubes continuously move upward in the activation fluidized bed 1, return to the heated fluidized bed 2 through the circulating carbon nanotube outlet 7, pipeline, and circulating carbon nanotube inlet 8, continue to be heated, and then return to the activation fluidized bed 1 to heat the activated carbon precursor. The carbon nanotubes in the entire preparation process circulate in the activation fluidized bed 1 and the heated fluidized bed 2 to keep the bed pressure drop and temperature in the activation fluidized bed 1 constant;

[0047] (3) Nitrogen is introduced into the activation fluidized bed 1 through the activation gas inlet 3, making the heated activated carbon precursor in a fluidized state under the action of the gas flow; the activation medium (H 2 O, with a flow rate of 0.05 - 0.2 m / s) is introduced into the activation fluidized bed 1 through the activation gas inlet 3. After etching and pore formation for 1 - 10 h on the activated carbon precursor heated to a temperature of 850 - 880 °C, ultrafine porous activated carbon is obtained; then the carbon nanotubes in the activation fluidized bed 1 are discharged to the heated fluidized bed 2 through the circulating carbon nanotube outlet 7, pipeline, and circulating carbon nanotube inlet 8, and the supply of carbon nanotubes to the activation fluidized bed 1 is stopped; the ultrafine porous activated carbon is discharged through the activated carbon product outlet 14 and cooled for standby; the activation tail gas is discharged from the activation fluidized bed 1 through the activation tail gas outlet 4; the fluidizing gas is discharged from the fluidizing gas outlet 11 of the heated fluidized bed 2; a new batch of activated carbon precursors is added to the activation fluidized bed 1, and then the heated carbon nanotubes are continuously supplied from the heated fluidized bed 2 to the activation fluidized bed 1 to resume the circulation of the carbon nanotubes, repeating the above preparation process;

[0048] (4) The circulation time of the carbon nanotubes added to the heated fluidized bed 2 in the entire reaction system in the same batch is controlled to be 3 days to obtain carbon nanotube products, which are discharged through the carbon nanotube product outlet 15 and collected; a new batch of carbon nanotubes is added to the heated fluidized bed 2 to continue the 3-day cycle of circulation; compared with the carbon nanotubes before use, the specific surface area of the collected carbon nanotube products increases by 10 - 20%, and the surface functional group density increases by 30 - 70%, which can be used as an efficient adsorbent for organic waste; the particle size of the ultrafine porous activated carbon is 1 - 10 microns, the specific surface area is 1500 - 2500 m 2 / g, and the pore volume is 0.5 - 2.5 mL / g.

[0049] Example 2

[0050] (1) Connect the activated fluidized bed 1 and the heating fluidized bed 2 with pipes to form a complete system. Fill the activated fluidized bed 1 with an activated carbon precursor (artificial polymer, polyacrylonitrile pre-oxide) having a particle size of 1 - 10 microns and a bulk density of 0.4 - 0.56 g / mL through the activated carbon precursor inlet 5. Then fill the heating fluidized bed 2 with carbon nanotubes formed by curling 10 - 40 carbon layers, having an outer diameter of 8 - 30 nm, an aspect ratio greater than 200, and a bulk density of 0.09 - 0.1 g / ml through the carbon nanotube inlet 12. Introduce the fluidizing gas (nitrogen) into the heating fluidized bed 2 through the fluidizing gas inlet 10 to make the carbon nanotubes in a fluidized state under the action of the gas flow;

[0051] (2) By introducing a high-temperature gas flow into the heat exchange tube 13 in the heating fluidized bed 2, heat the carbon nanotubes to a temperature of 980 °C. The heated carbon nanotubes are successively introduced into the activated fluidized bed 1 through the heat-carrying carbon nanotube outlet 9, the pipe, and the heat-carrying carbon nanotube inlet 6 to indirectly heat the activated carbon precursor to a temperature of 910 - 930 °C. In the activated fluidized bed 1, the volume ratio of the carbon nanotubes to the activated carbon precursor is maintained at 0.3 - 0.4. During the entire preparation process, the carbon nanotubes continuously move upward in the activated fluidized bed 1, return to the heating fluidized bed 2 through the circulating carbon nanotube outlet 7, the pipe, and the circulating carbon nanotube inlet 8, continue to be heated, and then return to the activated fluidized bed 1 to heat the activated carbon precursor. The carbon nanotubes in the entire preparation process circulate between the activated fluidized bed 1 and the heating fluidized bed 2 to keep the bed pressure drop and temperature in the activated fluidized bed 1 constant;

[0052] (3) Introduce nitrogen into the activated fluidized bed 1 through the activation gas inlet 3 to make the heated activated carbon precursor in a fluidized state under the action of the gas flow. Introduce the activation medium (CO 2 , with a flow rate of 0.1 - 0.12 m / s) into the activated fluidized bed 1 through the activation gas inlet 3, etch and create pores in the activated carbon precursor heated to a temperature of 850 - 880 °C for 8 - 10 h to obtain ultrafine porous activated carbon. Then discharge the carbon nanotubes in the activated fluidized bed 1 to the heating fluidized bed 2 through the circulating carbon nanotube outlet 7, the pipe, and the circulating carbon nanotube inlet 8, and stop supplementing carbon nanotubes to the activated fluidized bed 1. Discharge the ultrafine porous activated carbon through the activated carbon product outlet 14 and cool it for standby. Discharge the activation tail gas from the activated fluidized bed 1 through the activation tail gas outlet 4. Discharge the fluidizing gas from the fluidizing gas outlet 11 of the heating fluidized bed 2. Add a new batch of activated carbon precursors to the activated fluidized bed 1, and then continue to supplement the heated carbon nanotubes from the heating fluidized bed 2 to the activated fluidized bed 1 to resume the circulation of the carbon nanotubes, and repeat the above preparation process;

[0053] (4) Control the circulation time of the same batch of carbon nanotubes added to the heated fluidized bed 2 in the entire reaction system to be 3 days to obtain carbon nanotube products, which are discharged through the carbon nanotube product outlet 15 and collected; add a new batch of carbon nanotubes to the heated fluidized bed 2 and continue the next 3-day circulation; the specific surface area of the collected carbon nanotube products has increased by 15% compared to the carbon nanotubes before use, and the surface functional group density has increased by 50%, which can be used as an efficient adsorbent for organic waste; the particle size of the ultrafine porous activated carbon is 1-10 microns, the specific surface area is 2200m 2 / g, and the pore volume is 2.5 mL / g.

[0054] Example 3

[0055] (1) Connect the activation fluidized bed 1 and the heated fluidized bed 2 with pipelines to form a complete system; fill the activation fluidized bed 1 with an activated carbon precursor (biomass, apricot shell) with a particle size of 6-10 microns and a bulk density of 0.3-0.4 g / mL through the activated carbon precursor inlet 5, and then fill the heated fluidized bed 2 with carbon nanotubes composed of 40-100 carbon layers curled, with an outer diameter of 40-80 nm, an aspect ratio greater than 200, and a bulk density of 0.08-0.1 g / ml through the carbon nanotube inlet 12; introduce the fluidizing gas (nitrogen) into the heated fluidized bed 2 through the fluidizing gas inlet 10 to make the carbon nanotubes in a fluidized state under the action of the gas flow;

[0056] (2) Heat the carbon nanotubes to a temperature of 1000 °C through the heating rod 13 in the heated fluidized bed 2. The heated carbon nanotubes are successively introduced into the activation fluidized bed 1 through the heat-carrying carbon nanotube outlet 9, pipeline, and heat-carrying carbon nanotube inlet 6, indirectly heating the activated carbon precursor to a temperature of 920-950 °C; in the activation fluidized bed 1, the volume ratio of the carbon nanotubes to the activated carbon precursor is maintained at 1.25; during the entire preparation process, the carbon nanotubes continuously move upward in the activation fluidized bed 1, return to the heated fluidized bed 2 through the circulating carbon nanotube outlet 7, pipeline, and circulating carbon nanotube inlet 8, continue to be heated, and then return to the activation fluidized bed 1 to heat the activated carbon precursor. The carbon nanotubes in the entire preparation process circulate in the activation fluidized bed 1 and the heated fluidized bed 2 to keep the bed pressure drop and temperature in the activation fluidized bed 1 constant;

[0057] (3) Introduce nitrogen into the activation fluidized bed 1 through the activation gas inlet 3 to make the heated activated carbon precursor in a fluidized state under the action of the gas flow; introduce the activation medium (H 2O, at a flow rate of 0.05 - 0.1 m / s) is introduced into the activation fluidized bed 1 through the activation gas inlet 3. After etching and pore formation for 2 - 6 h on the activated carbon precursor heated to a temperature of 920 - 950 °C, ultrafine porous activated carbon is obtained; then the carbon nanotubes in the activation fluidized bed 1 are discharged to the heating fluidized bed 2 through the circulating carbon nanotube outlet 7, pipeline and the circulating carbon nanotube inlet 8, and the supply of carbon nanotubes to the activation fluidized bed 1 is stopped; the ultrafine porous activated carbon is discharged through the activated carbon product outlet 14 and cooled for standby; the activation tail gas is discharged from the activation fluidized bed 1 through the activation tail gas outlet 4; the fluidization gas is discharged from the fluidization gas outlet 11 of the heating fluidized bed 2; then a new batch of activated carbon precursors is added to the activation fluidized bed 1, and then the heated carbon nanotubes are continuously supplied from the heating fluidized bed 2 to the activation fluidized bed 1 to resume the circulating flow of the carbon nanotubes, and the above preparation process is repeated;

[0058] (4) Control the circulating flow time of the carbon nanotubes added to the heating fluidized bed 2 in the whole reaction system for 3 days to obtain carbon nanotube products, which are discharged through the carbon nanotube product outlet 15 and collected; a new batch of carbon nanotubes is added to the heating fluidized bed 2 to continue the circulating flow for the next cycle of 3 days; the collected carbon nanotube products have a 20% increase in specific surface area and a 70% increase in surface functional group density compared with the carbon nanotubes before use, and can be used as efficient adsorbents for organic waste; the particle size of the ultrafine porous activated carbon is 1 - 10 microns, and the specific surface area is 1500 m 2 / g, and the pore volume is 0.5 mL / g.

[0059] Example 4

[0060] (1) Connect the activation fluidized bed 1 and the heating fluidized bed 2 with pipelines to form a complete system; fill the activation fluidized bed 1 with activated carbon precursors (artificial polymer, phenolic resin) with a particle size of 5 - 8 microns and a bulk density of 0.6 - 0.8 g / mL through the activated carbon precursor inlet 5, and then fill the heating fluidized bed 2 with carbon nanotubes formed by curling 10 - 50 carbon layers, with an outer diameter of 8 - 40 nm, an aspect ratio greater than 200, and a bulk density of 0.05 - 0.06 g / ml through the carbon nanotube inlet 12; introduce the fluidization gas (nitrogen) into the heating fluidized bed 2 through the fluidization gas inlet 10 to make the carbon nanotubes in a fluidized state under the action of the gas flow;

[0061] (2) By introducing a high-temperature gas stream into the heat exchange tubes 13 in the heated fluidized bed 2, the carbon nanotubes are heated to a temperature of 950 °C. The heated carbon nanotubes are successively introduced into the activation fluidized bed 1 through the heat-carrying carbon nanotube outlet 9, pipeline, and heat-carrying carbon nanotube inlet 6, indirectly heating the activated carbon precursor to a temperature of 850 - 920 °C; in the activation fluidized bed 1, the volume ratio of carbon nanotubes to the activated carbon precursor is maintained at 1.2; during the entire preparation process, the carbon nanotubes continuously move upward in the activation fluidized bed 1, return to the heated fluidized bed 2 through the circulating carbon nanotube outlet 7, pipeline, and circulating carbon nanotube inlet 8, continue to be heated, and then return to the activation fluidized bed 1 to heat the activated carbon precursor. The carbon nanotubes in the entire preparation process circulate in the activation fluidized bed 1 and the heated fluidized bed 2 to keep the bed pressure drop and temperature in the activation fluidized bed 1 constant;

[0062] (3) Nitrogen is introduced into the activation fluidized bed 1 through the activation gas inlet 3, making the heated activated carbon precursor in a fluidized state under the action of the gas stream; the activation medium (CO 2 with a volume fraction of 50%, H 2 O with a volume fraction of 50%, and a flow rate of 0.15 - 0.2 m / s) is introduced into the activation fluidized bed 1 through the activation gas inlet 3. After etching and pore formation for 1 - 3 h on the activated carbon precursor heated to a temperature of 850 - 920 °C, ultrafine porous activated carbon is obtained; then the carbon nanotubes in the activation fluidized bed 1 are discharged to the heated fluidized bed 2 through the circulating carbon nanotube outlet 7, pipeline, and circulating carbon nanotube inlet 8, and the supply of carbon nanotubes to the activation fluidized bed 1 is stopped; the ultrafine porous activated carbon is discharged through the activated carbon product outlet 14 and cooled for standby; the activation tail gas is discharged from the activation fluidized bed 1 through the activation tail gas outlet 4; the fluidizing gas is discharged from the fluidizing gas outlet 11 of the heated fluidized bed 2; a new batch of activated carbon precursors is added to the activation fluidized bed 1, and then the heated carbon nanotubes are continuously supplied from the heated fluidized bed 2 to the activation fluidized bed 1 to resume the circulation of the carbon nanotubes, repeating the above preparation process;

[0063] (4) The circulation time of the carbon nanotubes added to the heated fluidized bed 2 in the entire reaction system in the same batch is controlled to be 3 days to obtain carbon nanotube products, which are discharged through the carbon nanotube product outlet 15 and collected; a new batch of carbon nanotubes is added to the heated fluidized bed 2 to continue the 3-day cycle of circulation; the collected carbon nanotube products have a 10% increase in specific surface area and a 30% increase in surface functional group density compared to the carbon nanotubes before use, and can be used as efficient adsorbents for organic waste; the ultrafine porous activated carbon has a particle size of 1 - 10 microns, a specific surface area of 2500 m 2 / g, and a pore volume of 1.5 mL / g.

[0064] Example 5

[0065] (1) Connect the activated fluidized bed 1 and the heating fluidized bed 2 with pipes to form a complete system; fill the activated carbon precursor (biomass, plant starch) with a particle size of 4 - 8 microns and a bulk density of 0.3 - 0.5 g / mL into the activated fluidized bed 1 through the activated carbon precursor inlet 5, and then fill the carbon nanotubes composed of 10 - 20 carbon layers curled, with an outer diameter of 8 - 16 nm, an aspect ratio greater than 200, and a bulk density of 0.06 - 0.07 g / ml into the heating fluidized bed 2 through the carbon nanotube inlet 12; introduce the fluidizing gas (nitrogen) into the heating fluidized bed 2 through the fluidizing gas inlet 10 to make the carbon nanotubes in a fluidized state under the action of the gas flow;

[0066] (2) Heat the carbon nanotubes to a temperature of 930 °C through the electric heating rod 13 in the heating fluidized bed 2. The heated carbon nanotubes are successively introduced into the activated fluidized bed 1 through the heat-carrying carbon nanotube outlet 9, pipes, and the heat-carrying carbon nanotube inlet 6 to indirectly heat the activated carbon precursor to a temperature of 870 - 900 °C; in the activated fluidized bed 1, the volume ratio of the carbon nanotubes to the activated carbon precursor is maintained at 0.7; during the whole preparation process, the carbon nanotubes continuously move upward in the activated fluidized bed 1, return to the heating fluidized bed 2 through the circulating carbon nanotube outlet 7, pipes, and the circulating carbon nanotube inlet 8, continue to be heated, and then return to the activated fluidized bed 1 to heat the activated carbon precursor. The carbon nanotubes in the whole preparation process circulate in the activated fluidized bed 1 and the heating fluidized bed 2 to keep the bed pressure drop and temperature in the activated fluidized bed 1 constant;

[0067] (3) Introduce nitrogen into the activated fluidized bed 1 through the activation gas inlet 3 to make the heated activated carbon precursor in a fluidized state under the action of the gas flow; introduce the activation medium (CO 2 with a volume fraction of 40%, H 2 O with a volume fraction of 60%, and a flow rate of 0.12 - 0.15 m / s) into the activated fluidized bed 1 through the activation gas inlet 3, etch and create pores in the activated carbon precursor heated to a temperature of 870 - 900 °C for 6 - 7 h to obtain ultrafine porous activated carbon; then discharge the carbon nanotubes in the activated fluidized bed 1 to the heating fluidized bed 2 through the circulating carbon nanotube outlet 7, pipes, and the circulating carbon nanotube inlet 8, and stop supplementing carbon nanotubes to the activated fluidized bed 1; discharge the ultrafine porous activated carbon through the activated carbon product outlet 14 and cool it for standby; discharge the activation tail gas from the activation tail gas outlet 4 from the activated fluidized bed 1; discharge the fluidizing gas from the fluidizing gas outlet 11 of the heating fluidized bed 2; add a new batch of activated carbon precursors to the activated fluidized bed 1, and then continue to supplement the heated carbon nanotubes from the heating fluidized bed 2 to the activated fluidized bed 1 to resume the circulation of the carbon nanotubes, and repeat the above preparation process;

[0068] (4) Control the circulation time of the same batch of carbon nanotubes added to the heated fluidized bed 2 in the entire reaction system to be 3 days to obtain carbon nanotube products, which are discharged through the carbon nanotube product outlet 15 and collected; add a new batch of carbon nanotubes to the heated fluidized bed 2 and continue the 3-day circulation; the collected carbon nanotube products have a 15% increase in specific surface area and a 40% increase in surface functional group density compared to the carbon nanotubes before use, and can be used as efficient adsorbents for organic waste; the ultrafine porous activated carbon has a particle size of 1 - 10 microns, a specific surface area of 2200 m 2 / g, and a pore volume of 1.3 mL / g.

[0069] Example 6

[0070] (1) Connect the activation fluidized bed 1 and the heated fluidized bed 2 with pipelines to form a complete system; fill the activation fluidized bed 1 with an activated carbon precursor (biomass, lignin) with a particle size of 4 - 8 microns and a bulk density of 0.4 - 0.6 g / mL through the activated carbon precursor inlet 5, and then fill the heated fluidized bed 2 with carbon nanotubes formed by curling 20 - 50 carbon layers, with an outer diameter of 15 - 40 nm, an aspect ratio greater than 200, and a bulk density of 0.065 - 0.08 g / ml through the carbon nanotube inlet 12; introduce the fluidizing gas (nitrogen) into the heated fluidized bed 2 through the fluidizing gas inlet 10 to make the carbon nanotubes in a fluidized state under the action of the gas flow;

[0071] (2) Pass a high-temperature gas flow through the heat exchange tube 13 in the heated fluidized bed 2 to heat the carbon nanotubes to a temperature of 880 °C. The heated carbon nanotubes are sequentially passed through the heat-carrying carbon nanotube outlet 9, pipeline, and heat-carrying carbon nanotube inlet 6 into the activation fluidized bed 1 to indirectly heat the activated carbon precursor to a temperature of 850 °C; in the activation fluidized bed 1, the volume ratio of carbon nanotubes to the activated carbon precursor is maintained at 0.4 - 0.5; during the entire preparation process, the carbon nanotubes continuously move upward in the activation fluidized bed 1, return to the heated fluidized bed 2 through the circulating carbon nanotube outlet 7, pipeline, and circulating carbon nanotube inlet 8, continue to be heated, and then return to the activation fluidized bed 1 to heat the activated carbon precursor. The carbon nanotubes in the entire preparation process circulate in the activation fluidized bed 1 and the heated fluidized bed 2 to keep the bed pressure drop and temperature in the activation fluidized bed 1 constant;

[0072] (3) Pass nitrogen into the activation fluidized bed 1 through the activation gas inlet 3 to make the heated activated carbon precursor in a fluidized state under the action of the gas flow; the activation medium (CO 2 with a volume fraction of 20%, H 2With a volume fraction of 80% and a flow rate of 0.11 - 0.13 m / s, it is introduced into the activation fluidized bed 1 through the activation gas inlet 3. After etching and pore formation for 1 - 3 hours on the activated carbon precursor heated to 850 °C, ultrafine porous activated carbon is obtained. Then, the carbon nanotubes in the activation fluidized bed 1 are discharged to the heating fluidized bed 2 through the circulating carbon nanotube outlet 7, pipeline, and circulating carbon nanotube inlet 8, and the supply of carbon nanotubes to the activation fluidized bed 1 is stopped. The ultrafine porous activated carbon is discharged through the activated carbon product outlet 14 and cooled for standby. The activation tail gas is discharged from the activation fluidized bed 1 through the activation tail gas outlet 4. The fluidizing gas is discharged from the fluidizing gas outlet 11 of the heating fluidized bed 2. Then, a new batch of activated carbon precursors is added to the activation fluidized bed 1, and then the heated carbon nanotubes are continuously supplied from the heating fluidized bed 2 to the activation fluidized bed 1 to resume the circulating flow of the carbon nanotubes, and the above preparation process is repeated.

[0073] (4) Control the circulating flow time of the carbon nanotubes added to the heating fluidized bed 2 in the entire reaction system to be 3 days to obtain carbon nanotube products, which are discharged through the carbon nanotube product outlet 15 and collected. A new batch of carbon nanotubes is added to the heating fluidized bed 2 to continue the circulating flow for the next 3 - day cycle. The specific surface area of the collected carbon nanotube products has increased by 14% compared to the carbon nanotubes before use, and the surface functional group density has increased by 45%. They can be used as high - efficiency adsorbents for organic waste. The particle size of the ultrafine porous activated carbon is 1 - 10 microns, the specific surface area is 2100 m 2 / g, and the pore volume is 0.9 mL / g.

[0074] Example 7

[0075] (1) Connect the activation fluidized bed 1 and the heating fluidized bed 2 with pipelines to form a complete system. Fill the activation fluidized bed 1 with activated carbon precursors (artificial polymer, furan resin) with a particle size of 5 - 7 microns and a bulk density of 0.6 - 0.7 g / mL through the activated carbon precursor inlet 5. Then, fill the heating fluidized bed 2 with carbon nanotubes formed by curling 20 - 40 carbon layers, with an outer diameter of 15 - 30 nm, an aspect ratio greater than 200, and a bulk density of 0.09 - 0.1 g / ml through the carbon nanotube inlet 12. Introduce the fluidizing gas (nitrogen) into the heating fluidized bed 2 through the fluidizing gas inlet 10 to make the carbon nanotubes in a fluidized state under the action of the gas flow.

[0076] (2) By introducing high-temperature gas into the heat exchange tubes 13 in the heating fluidized bed 2, the carbon nanotubes are heated to a temperature of 940 °C. The heated carbon nanotubes are successively introduced into the activation fluidized bed 1 through the heat-carrying carbon nanotube outlet 9, pipeline and heat-carrying carbon nanotube inlet 6, indirectly heating the activated carbon precursor to a temperature of 920 °C; in the activation fluidized bed 1, the volume ratio of carbon nanotubes to the activated carbon precursor is maintained at 0.8; during the whole preparation process, the carbon nanotubes continuously move upward in the activation fluidized bed 1, return to the heating fluidized bed 2 through the circulating carbon nanotube outlet 7, pipeline and circulating carbon nanotube inlet 8, continue to be heated, and then return to the activation fluidized bed 1 to heat the activated carbon precursor. The carbon nanotubes in the whole preparation process circulate in the activation fluidized bed 1 and the heating fluidized bed 2 to keep the bed pressure drop and temperature in the activation fluidized bed 1 constant;

[0077] (3) Nitrogen is introduced into the activation fluidized bed 1 through the activation gas inlet 3, so that the heated activated carbon precursor is in a fluidized state under the action of the gas flow; the activation medium (CO 2 , with a flow rate of 0.10 - 0.14 m / s) is introduced into the activation fluidized bed 1 through the activation gas inlet 3. After etching and pore formation for 7 - 8 h on the activated carbon precursor heated to a temperature of 920 °C, ultrafine porous activated carbon is obtained; then the carbon nanotubes in the activation fluidized bed 1 are discharged to the heating fluidized bed 2 through the circulating carbon nanotube outlet 7, pipeline and circulating carbon nanotube inlet 8, and the supply of carbon nanotubes to the activation fluidized bed 1 is stopped; the ultrafine porous activated carbon is discharged through the activated carbon product outlet 14 and cooled for standby; the activation tail gas is discharged from the activation fluidized bed 1 through the activation tail gas outlet 4; the fluidization gas is discharged from the fluidization gas outlet 11 of the heating fluidized bed 2; a new batch of activated carbon precursors is added to the activation fluidized bed 1, and then the heated carbon nanotubes are continuously supplied from the heating fluidized bed 2 to the activation fluidized bed 1 to resume the circulation of the carbon nanotubes, and the above preparation process is repeated;

[0078] (4) The circulation time of the carbon nanotubes added to the heating fluidized bed 2 in the whole reaction system in one batch is controlled to be 3 days to obtain carbon nanotube products, which are discharged through the carbon nanotube product outlet 15 and collected; a new batch of carbon nanotubes is added to the heating fluidized bed 2 to continue the 3-day cycle of circulation; compared with the carbon nanotubes before use, the specific surface area of the collected carbon nanotube products increases by 20%, and the surface functional group density increases by 65%, which can be used as an efficient adsorbent for organic waste; the particle size of the ultrafine porous activated carbon is 1 - 10 microns, the specific surface area is 2400 m 2 / g, and the pore volume is 1.6 mL / g.

[0079] Example 8

[0080] (1) Connect the activated fluidized bed 1 and the heating fluidized bed 2 with pipes to form a complete system; fill the activated carbon precursor (50 wt% coconut shell and 50 wt% phenolic resin) with a particle size of 6 - 7 microns and a bulk density of 0.45 - 0.65 g / mL into the activated fluidized bed 1 through the activated carbon precursor inlet 5, and then fill the carbon nanotubes with an outer diameter of 35 - 48 nm, a length-to-diameter ratio greater than 200, and a bulk density of 0.056 - 0.078 g / ml, which are formed by curling 40 - 50 carbon layers, into the heating fluidized bed 2 through the carbon nanotube inlet 12; introduce the fluidizing gas (nitrogen) into the heating fluidized bed 2 through the fluidizing gas inlet 10 to make the carbon nanotubes in a fluidized state under the action of the gas flow;

[0081] (2) By introducing a high-temperature gas flow into the heat exchange tube 13 in the heating fluidized bed 2, heat the carbon nanotubes to a temperature of 965 °C. The heated carbon nanotubes are successively introduced into the activated fluidized bed 1 through the heat-carrying carbon nanotube outlet 9, the pipe, and the heat-carrying carbon nanotube inlet 6 to indirectly heat the activated carbon precursor to a temperature of 870 - 890 °C; in the activated fluidized bed 1, the volume ratio of the carbon nanotubes to the activated carbon precursor is maintained at 1.3 - 1.5; during the whole preparation process, the carbon nanotubes continuously move upward in the activated fluidized bed 1, return to the heating fluidized bed 2 through the circulating carbon nanotube outlet 7, the pipe, and the circulating carbon nanotube inlet 8, continue to be heated, and then return to the activated fluidized bed 1 to heat the activated carbon precursor. The carbon nanotubes in the whole preparation process circulate in the activated fluidized bed 1 and the heating fluidized bed 2 to keep the bed pressure drop and temperature in the activated fluidized bed 1 constant;

[0082] (3) Introduce nitrogen into the activated fluidized bed 1 through the activation gas inlet 3 to make the heated activated carbon precursor in a fluidized state under the action of the gas flow; introduce the activation medium (H 2 O, flow rate of 0.15 - 0.2 m / s) into the activated fluidized bed 1 through the activation gas inlet 3, etch and pore-form the activated carbon precursor heated to a temperature of 870 - 890 °C for 2 - 4 h to obtain ultrafine porous activated carbon; then discharge the carbon nanotubes in the activated fluidized bed 1 to the heating fluidized bed 2 through the circulating carbon nanotube outlet 7, the pipe, and the circulating carbon nanotube inlet 8, and stop supplementing the carbon nanotubes to the activated fluidized bed 1; discharge the ultrafine porous activated carbon through the activated carbon product outlet 14 and cool it for standby; discharge the activation tail gas from the activated fluidized bed 1 through the activation tail gas outlet 4; discharge the fluidizing gas from the fluidizing gas outlet 11 of the heating fluidized bed 2; add a new batch of activated carbon precursors to the activated fluidized bed 1, and then continue to supplement the heated carbon nanotubes from the heating fluidized bed 2 to the activated fluidized bed 1 to resume the circulation of the carbon nanotubes, and repeat the above preparation process;

[0083] (4) Control the circulating flow time of the same batch of carbon nanotubes added to the heating fluidized bed 2 in the entire reaction system to be 3 days to obtain carbon nanotube products, which are discharged through the carbon nanotube product outlet 15 and collected; add a new batch of carbon nanotubes to the heating fluidized bed 2 and continue the circulating flow for the next 3-day cycle; the specific surface area of the collected carbon nanotube products has increased by 18% compared to the carbon nanotubes before use, and the surface functional group density has increased by 60%, and they can be used as efficient adsorbents for organic waste; the particle size of the ultra-fine porous activated carbon is 1-10 microns, the specific surface area is 1800 m 2 / g, and the pore volume is 1.45 mL / g.

[0084] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.

[0085] For method embodiments, for simplicity of description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and components involved are not necessarily essential to the present invention.

[0086] The above has introduced in detail a preparation method and device of ultra-fine porous activated carbon based on carbon nanotube circulation provided by the present invention. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A method for preparing ultrafine porous activated carbon based on carbon nanotube circulation, characterized in that: include: The activated carbon precursor is filled in an activated fluidized bed, and the carbon nanotubes are filled in a heated fluidized bed; The carbon nanotubes are heated to a temperature of 880-1000° C. by heating the fluidized bed, and then introduced into the activated fluidized bed to heat the activated carbon precursor to a temperature of 800-950° C.; Nitrogen and an activation medium are introduced from the bottom of the fluidized bed to make the heated activated carbon precursor in a fluidized state under the action of the airflow; after the activation medium etches and forms pores in the heated activated carbon precursor for 1-10 hours, the obtained ultrafine porous activated carbon is discharged through the product outlet; The carbon nanotubes circulate in the activated fluidized bed and the heated fluidized bed so that the bed pressure drop and temperature in the activated fluidized bed are kept constant; Wherein, the particle size of the activated carbon precursor is 1-10 microns; the bulk density of the activated carbon precursor is 0.3-0.8 g / mL; The activation medium is one or both of carbon dioxide and water vapor; The particle size of the ultrafine porous activated carbon is 1-10 microns; the specific surface area of ​​the ultrafine porous activated carbon is 1500-2500m 2 / g; the pore volume of the ultrafine porous activated carbon is 0.5-2.5mL / g.

2. The method according to claim 1, characterized in that: The circulation time of the carbon nanotubes is 3 days, and when the ultrafine porous activated carbon is discharged through the product outlet, the circulation of the carbon nanotubes is suspended; After the ultrafine porous activated carbon is discharged through the product outlet, a new batch of activated carbon precursor is added to the activated fluidized bed, and then the circulation flow of the carbon nanotubes is continued; When the circulation flow time of the carbon nanotubes exceeds 3 days, they are extracted and used as a highly efficient adsorbent for organic waste.

3. The method according to claim 1, characterized in that: The activated carbon precursor is biomass or artificial polymer; the biomass is one or more of coconut shell, apricot shell, plant starch, and lignin; the artificial polymer is one or more of phenolic resin, furan resin, and polyacrylonitrile pre-oxidation.

4. The method according to claim 1, characterized in that: The carbon nanotube is formed by curling 10-100 carbon layers; the stacking density of the carbon nanotube is 0.05-0.1 g / mL; the outer diameter of the carbon nanotube is 8-80 nm; and the aspect ratio of the carbon nanotube is greater than 200.

5. The method according to claim 1, characterized in that In the activated fluidized bed, the volume ratio of the carbon nanotubes to the activated carbon precursor is 0.3-1.

5.

6. The method according to claim 1, characterized in that The heating method of the heated fluidized bed is heating by introducing high-temperature airflow or electric heating.

7. The method according to claim 1, characterized in that The flow rate of the activation medium is 0.05-0.2 m / s.

8. A preparation device for ultrafine porous activated carbon based on carbon nanotube circulation, the preparation device is applicable to any of the methods described in claims 1-7, characterized in that: The device comprises an activated fluidized bed, and the activated fluidized bed is used to react the activated carbon precursor under the action of carbon nanotubes and an activation medium to obtain ultrafine porous activated carbon; A heating fluidized bed connected to the activation fluidized bed, used to heat the carbon nanotubes in the heating fluidized bed; The carbon nanotubes circulate between the activated fluidized bed and the heated fluidized bed through a pipeline.

9. The device according to claim 8, characterized in that The heated fluidized bed is provided with heat exchange tubes or electric heating rods to heat the carbon nanotubes in the heated fluidized bed; the heat exchange tubes heat the carbon nanotubes in the heated fluidized bed through the high-temperature airflow in the tubes.

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