A system and method for preparing fullerenes by catalytic pyrolysis of biomass

Abstract

The present invention discloses a system and method for preparing fullerenes by catalytic pyrolysis of biomass, and relates to the technical field of fullerenes. The system for preparing fullerenes by catalytic pyrolysis of biomass disclosed in the present invention comprises a reaction unit, a temperature control unit, a vacuum unit, a feeding unit, a gas supply unit, and a collection unit. The reaction unit comprises a low-temperature heating zone, a high-temperature heating zone, and a cooling zone. By using the system to perform the three-stage heating and cooling treatment on the reaction raw materials, C 60 、C 70 and / or large fullerenes, and the yield is high, which is suitable for industrial application.

Description

Technical Field

[0001] The present invention relates to the technical field of fullerenes, and in particular to a system and method for preparing fullerenes by catalytic pyrolysis of biomass. Background Art

[0002] Fullerene is a molecule composed of carbon atoms that are connected by sp 2 Hybrid bonds connect to form a combination of pentagons and hexagons, and the shape of the molecule is similar to a sphere or ellipsoid. Typical fullerenes include C 60 、C 70 The unique structure of fullerenes gives them special chemical and physical properties, showing a wide range of application potentials in many fields, including materials science, electronics, medicine, environmental protection, and catalysis industry.

[0003] Currently, large-scale synthesis of fullerenes relies primarily on arc discharge, flame combustion, laser evaporation, plasma, and pyrolysis methods. The flame combustion method allows for continuous production and offers the advantage of high yields, but it also has limitations such as high energy consumption and high risk. The pyrolysis method, which typically assembles fullerenes by pyrolyzing polycyclic aromatic hydrocarbons or other small hydrocarbon molecules at around 2000°C, is a more suitable method for experimental research and large-scale production due to its controllable temperature. However, the pyrolysis method typically requires industrially important compounds such as benzene and polycyclic aromatic hydrocarbons as raw materials, which can easily lead to a waste of fossil energy.

[0004] Plant-based biomass, currently the fourth largest energy source on Earth after coal, oil, and natural gas, is extremely widespread and abundant. Since biomass pyrolysis can produce large quantities of phenols and furans, catalytic pyrolysis of biomass, when combined with a catalyst, can produce aromatic hydrocarbons, ideal raw materials for the production of fullerenes via pyrolysis.

[0005] CN 102060290 A discloses a method for producing fullerenes using biomass combustion. This method requires combustion in a high-concentration oxygen environment, resulting in violent combustion that is difficult to control and highly dangerous. Furthermore, existing methods for producing fullerenes using biomass often have low yields and complex processes. Summary of the Invention

[0006] The main purpose of the present invention is to provide a system and method for preparing fullerenes by catalytic pyrolysis of biomass, so as to solve the problems of complex process, low controllability and low fullerene yield in the prior art of preparing fullerenes from biomass.

[0007] To achieve the above objectives, according to a first aspect of the present invention, a system for preparing fullerenes by catalytic pyrolysis of biomass is provided, comprising:

[0008] The reaction unit includes a feed port and a discharge port. A low-temperature heating zone, a high-temperature heating zone, and a cooling zone are sequentially arranged adjacent to each other in the direction from the feed port to the discharge port. The reaction unit is used to perform a catalytic pyrolysis reaction of biomass.

[0009] The temperature control unit includes a low-temperature heating device arranged outside the low-temperature heating zone in the reaction unit, a high-temperature heating device arranged outside the high-temperature heating zone in the reaction unit, and a temperature control device arranged outside the cooling zone in the reaction unit. The temperature control unit is used to control the temperature of each zone of the reaction unit;

[0010] The vacuum unit includes a vacuum cavity provided outside the reaction unit and a vacuum pump group for controlling the vacuum degree of the vacuum cavity; the vacuum unit is used to provide a vacuum environment for the reaction unit;

[0011] A feeding unit, connected to the feed port of the reaction unit, for providing reaction raw materials;

[0012] A gas supply unit connected to the feed inlet of the reaction unit;

[0013] The collecting unit is connected to the discharge port of the reaction unit and is used to collect the reaction products.

[0014] Furthermore, the collection unit includes:

[0015] A collecting container connected to the discharge port in the reaction unit;

[0016] The smoke filter device is connected to the top or upper side of the collection container. The smoke filter device includes a filter screen and an exhaust gas collection container, and the filter screen is located between the collection container and the exhaust gas collection container.

[0017] Furthermore, the mesh size of the filter is 200-400 meshes.

[0018] Furthermore, the reaction unit is one of a graphite tube, a silicon carbide tube, a corundum tube, and a boron nitride tube; and / or the temperature control device is a water-cooled heat exchanger.

[0019] Furthermore, the vacuum unit is also provided with a low-temperature heating zone temperature measuring window and a high-temperature heating zone temperature measuring window; the low-temperature heating zone temperature measuring window is provided corresponding to the low-temperature heating zone and is used to monitor the temperature of the low-temperature heating zone of the reaction unit, and the high-temperature heating zone temperature measuring window is provided corresponding to the high-temperature heating zone and is used to monitor the temperature of the high-temperature heating zone of the reaction unit; and / or, a flow controller is also provided between the gas supply unit and the feed port of the reaction unit, and the flow controller is used to control the gas flow.

[0020] According to a second aspect of the present invention, a method for preparing fullerenes by catalytic pyrolysis of biomass is provided. The method uses the system of the first aspect of the present invention to prepare fullerenes, comprising the following steps:

[0021] S1, introducing the biomass material and the catalyst into the reaction unit, performing a first heating in the low-temperature heating zone to obtain a first intermediate product;

[0022] S2, the first intermediate product enters the high-temperature heating zone for a second heating to obtain a second intermediate product;

[0023] S3, the second intermediate product enters a cooling zone for cooling to obtain a reaction product;

[0024] S4, filtering and purifying the flue gas in the reaction product to obtain fullerene;

[0025] In S1, the temperature of the first heating is 300-600°C; in S2, the temperature of the second heating is 1500-2500°C; in S3, the temperature of the cooling is 25-70°C; and the carrier gas is continuously introduced during the preparation of fullerene.

[0026] Furthermore, in S1, the biomass material and the catalyst are first granulated separately, or the mixture of the biomass material and the catalyst is granulated, and the average particle size of the obtained particles is 40-60 meshes.

[0027] Furthermore, in S2, the temperature of the second heating is 1700-2300°C.

[0028] Furthermore, in S3, the cooling temperature is 30-50°C.

[0029] Furthermore, when the length of the low-temperature heating zone in the reaction unit (1) is 3-7 cm, the length of the high-temperature heating zone is 8-12 cm, and the length of the cooling zone is 2-4 cm, the flow rate of the carrier gas is 30-70 sccm.

[0030] Furthermore, the mass ratio of the biomass material to the catalyst is 1:2-2:1.

[0031] Furthermore, the biomass material is at least one of cellulose, lignin, and straw; the catalyst is at least one of zeolite molecular sieve, zirconium oxide, calcium oxide, and aluminum oxide; and the carrier gas is an inert gas.

[0032] The system for preparing fullerenes by catalytic pyrolysis of biomass disclosed in the present invention has a simple structure. Its reaction unit only has three reaction zones: a low-temperature heating zone, a high-temperature heating zone, and a cooling zone. Using this system, fullerenes can be prepared through a three-stage reaction. The system is easy to control the reaction process and has a high yield of fullerenes prepared using this system. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A structural diagram of a system for preparing fullerenes by catalytic pyrolysis of biomass in one embodiment of the present invention;

[0034] Figure 2 A structural diagram of a system for preparing fullerenes by catalytic pyrolysis of biomass in another embodiment of the present invention;

[0035] Figure 3 1 is a high performance liquid chromatogram of the material after filtration and purification of the attachments in Example 1 and Comparative Example 3 of the present invention;

[0036] Figure 4 This is a MALDI-TOF mass spectrum of the attachment extract in Example 1 of the present invention;

[0037] The above drawings include the following figure marks: 1. reaction unit; 2. low-temperature heating device; 3. high-temperature heating device; 4. temperature control device; 5. vacuum chamber; 6. vacuum pump group; 7. feeding unit; 8. gas supply unit; 9. collection unit; 10. collection container; 11. filter; 12. exhaust gas collection container; 13. temperature measuring window of low-temperature heating zone; 14. temperature measuring window of high-temperature heating zone; 15. flow controller. DETAILED DESCRIPTION

[0038] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0039] As described in the background of the present invention, the cost of using fossil energy to produce fullerenes is high. It has been discovered that fullerenes can be produced using biomass materials. Since biomass materials are renewable and abundant, they help reduce the production cost of fullerenes. However, the existing technology has the problems of complex processes for producing fullerenes from biomass, low yields, and low controllability of the reaction process. In order to solve the above problems, in a typical embodiment of the present invention, a system for producing fullerenes by catalytic pyrolysis of biomass is provided, and its structure is as follows: Figure 1 Shown, including:

[0040] The reaction unit 1 includes a feed port and a discharge port. A low-temperature heating zone, a high-temperature heating zone, and a cooling zone are sequentially arranged adjacent to each other in the direction from the feed port to the discharge port. The reaction unit 1 is used to perform a catalytic pyrolysis reaction of biomass.

[0041] The temperature control unit includes a low-temperature heating device 2 disposed outside the low-temperature heating zone of the reaction unit 1, a high-temperature heating device 3 disposed outside the high-temperature heating zone of the reaction unit 1, and a temperature control device 4 disposed outside the cooling zone of the reaction unit 1. The temperature control unit is used to control the temperature of each zone of the reaction unit 1;

[0042] A vacuum unit, comprising a vacuum chamber 5 disposed outside the reaction unit 1 and a vacuum pump assembly 6 for controlling the vacuum degree of the vacuum chamber 5 , the vacuum unit being used to provide a vacuum environment for the reaction unit 1;

[0043] A feeding unit 7 is connected to the feed port of the reaction unit 1 and is used to provide reaction raw materials;

[0044] The gas supply unit 8 is connected to the feed port of the reaction unit 1 and can be used to control the movement speed of the reaction raw materials in the reaction unit 1;

[0045] The collecting unit 9 is connected to the discharge port of the reaction unit 1 and is used to collect the reaction products.

[0046] By setting up a low-temperature heating zone, a high-temperature heating zone, and a cooling zone, a three-stage reaction can be achieved in the reaction unit 1. The biomass material is pyrolyzed into aromatic compounds in the low-temperature heating zone. In the high-temperature heating zone, the aromatic compounds are broken and polymerized. Finally, they are spliced ​​in the cooling zone to obtain fullerenes. The temperature control unit can achieve precise temperature control of the heating and cooling zones. The vacuum unit helps to maintain the stability of the preparation environment, avoid being affected by other gases, and help to improve the yield of fullerenes. In the above embodiment, the system structure for preparing fullerenes by catalytic pyrolysis of biomass is simple and easy to operate. The reaction process can be controlled by controlling the length of the low-temperature heating zone, the high-temperature heating zone, and the cooling zone, and the controllability is high. In addition, the reaction conditions can be precisely controlled by the temperature control unit and the vacuum unit, and the yield of fullerenes in the product is high, which is suitable for industrial production.

[0047] In a preferred embodiment of the present invention, the collecting unit 9 includes:

[0048] The collecting container 10 is connected to the discharge port of the reaction unit 1;

[0049] The smoke filtering device is connected to the top or upper side of the collection container 10 . The smoke filtering device includes a filter screen 11 and an exhaust gas collection container 12 , and the filter screen 11 is located between the collection container 10 and the exhaust gas collection container 12 .

[0050] The residue after the reaction will fall into the collection container 10, and the fullerene in the product will enter the flue gas filter device along with the light flue gas and be deposited on the filter 11 in the flue gas filter device.

[0051] In a preferred embodiment of the present invention, the mesh size of the filter 11 is 200-400 meshes. The above-mentioned limitation on the mesh size of the filter is to collect as much fullerene as possible and improve its yield without clogging the pipeline.

[0052] Typically, but not limiting, the reaction unit 1 is a high temperature resistant reaction tube, such as a graphite tube, a silicon carbide tube, a corundum tube, or a boron nitride tube. The above reaction tube is a commonly used heat resistant reaction tube that can withstand high reaction temperatures and is highly safe.

[0053] In a preferred embodiment of the present invention, the axial direction of the reaction unit 1 is parallel to the direction of gravity, and the axial direction of the reaction unit 1 is from the feed inlet to the discharge outlet. When the above design is met, the reaction raw materials can pass through the low-temperature heating zone, the high-temperature heating zone, and the cooling zone in sequence under the action of gravity without applying external force, thereby reducing the preparation cost.

[0054] Typically but not limitatively, the low-temperature heating device 2 and the high-temperature heating device 3 are each independently an electric heater or an induction heater, and the temperature control device 4 is a water-cooled heat exchanger.

[0055] In a preferred embodiment of the present invention, a low-temperature heating zone temperature measuring window 13 and a high-temperature heating zone temperature measuring window 14 are further provided on the vacuum unit; the low-temperature heating zone temperature measuring window 13 is provided corresponding to the low-temperature heating zone and is used to monitor the temperature of the low-temperature heating zone of the reaction unit 1, and the high-temperature heating zone temperature measuring window 14 is provided corresponding to the high-temperature heating zone and is used to monitor the temperature of the high-temperature heating zone of the reaction unit 1.

[0056] By providing the low-temperature heating zone temperature measuring window 13 and the high-temperature heating zone temperature measuring window 14, the reaction temperature can be precisely controlled to improve the yield of fullerene in the product.

[0057] Typically but not limiting, a flow controller 15 is provided between the gas supply unit 8 and the feed port of the reaction unit 1, and its structure is as follows: Figure 2 As shown, the flow controller 15 is used to control the gas flow.

[0058] In another typical embodiment of the present invention, a method for preparing fullerenes by catalytic pyrolysis of biomass is provided. The method uses the system of the above typical embodiment of the present invention to prepare fullerenes, and specifically comprises the following steps:

[0059] S1, introducing biomass material and catalyst into reaction unit 1, performing a first heating in a low-temperature heating zone to obtain a first intermediate product;

[0060] S2, the first intermediate product enters the high-temperature heating zone for a second heating to obtain a second intermediate product;

[0061] S3, the second intermediate product enters a cooling zone for cooling to obtain a reaction product;

[0062] S4, filtering and purifying the flue gas in the reaction product to obtain fullerene;

[0063] In S1, the temperature of the first heating is 300-600°C; in S2, the temperature of the second heating is 1500-2500°C; in S3, the temperature of the cooling is 25-70°C; and the carrier gas is continuously introduced during the preparation of fullerene.

[0064] The system in the above embodiment is used to prepare fullerenes. By setting the first heating temperature (i.e., the temperature of the low-temperature heating zone) to 300-600°C, the biomass material can be fully pyrolyzed into aromatic compounds under the action of the catalyst. Before the second heating, the content of aromatic compounds is high, which helps to increase the yield of fullerenes. By setting the second heating temperature (i.e., the temperature of the high-temperature heating zone) to 1500-2500°C, the volatile aromatic compounds produced by the first heating can be partially broken to obtain a suitable number of small molecules with a carbon number of 2. Since fullerenes are composed of five-membered rings and / or six-membered rings, the small molecules with a carbon number of 2 play the role of connecting the unbroken aromatic compounds with a carbon number of 6. Under the action of high temperature, splicing and dehydrogenation reactions occur to obtain open curled polycyclic aromatic hydrocarbon fragments. Finally, the temperature of the cooling zone is controlled to 25-70°C, which can increase the probability of collision and reaction between the small molecules with a carbon number of 2 and the aromatic compounds, so that the final splicing can occur to close the fullerene carbon cage and obtain the final product fullerene.

[0065] In a preferred embodiment of the present invention, the biomass material and catalyst are pelletized separately or the mixture of the biomass material and catalyst is pelletized before addition, with the resulting pellets having an average particle size of 40-60 mesh. The purpose of pre-pelletization and the aforementioned particle size restrictions is to facilitate quantitative delivery of the reaction raw materials, ensuring a moderate delivery rate within reaction unit 1 and sufficient heating.

[0066] In a preferred embodiment of the present invention, in S2, the second heating temperature is 1700-2300°C; in S3, the cooling temperature is 30-50°C. Cooling within the above range can achieve a moderate splicing rate, less by-products, and a higher fullerene yield.

[0067] In a preferred embodiment of the present invention, when the length of the low-temperature heating zone in the reaction unit 1 is 3-7 cm, the length of the high-temperature heating zone is 8-12 cm, and the length of the cooling zone is 2-4 cm, the flow rate of the carrier gas is 30-70 sccm.

[0068] By matching the carrier gas flow rate with the lengths of the low-temperature heating zone, high-temperature heating zone, and cooling zone in the reaction unit 1, the reaction time is controlled. Under the above conditions, the yield of fullerenes can be further improved.

[0069] In a preferred embodiment of the present invention, the mass ratio of the biomass material to the catalyst is 1:2-2:1.

[0070] The mass ratio of biomass material to catalyst has a certain influence on the pyrolysis rate of biomass material. Under the above conditions, biomass material can be fully pyrolyzed to form aromatic hydrocarbon compounds, which helps to increase the yield of fullerenes. In addition, the catalyst can also be fully utilized and the cost is not high.

[0071] Typically, but not limiting, the biomass material is at least one of cellulose, lignin, and straw; the catalyst is at least one of zeolite molecular sieve, zirconium oxide, calcium oxide, and aluminum oxide; and the carrier gas is an inert gas, such as at least one of helium, argon, and nitrogen.

[0072] Typically, but not limiting, purification is performed by high performance liquid chromatography, which is a commonly used purification method and an important separation and analysis method in the fields of chemistry, medicine, and industry.

[0073] The present application is further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0074] The materials and equipment used in the following examples and comparative examples are as follows: Figure 2 As shown:

[0075] Biomass material: Kraft lignin;

[0076] Catalyst: H-ZSM-5 molecular sieve;

[0077] Filter: 300 mesh;

[0078] Reactor: A three-temperature-zone vertical pyrolyzer, which can independently control the temperature of the low-temperature heating zone, high-temperature heating zone, and cooling zone. The reaction tube is a graphite tube, the low-temperature heater and the high-temperature heater are low-voltage, high-current DC power supplies (5V, 600A), and the cooling zone is temperature-controlled by a water-cooled heat exchanger. The reaction tube has an outer diameter of 6mm, an inner diameter of 4mm, and a total length of 18cm. The length of the low-temperature heating zone is 5cm, the length of the high-temperature heating zone is 10cm, and the length of the cooling zone is 3cm.

[0079] Example 1

[0080] An embodiment of the method for preparing fullerenes by catalytic pyrolysis of biomass according to the present invention comprises the following steps:

[0081] S1, mixing the biomass material and the catalyst in a mass ratio of 1:1, pelletizing to obtain particles with an average particle size of 60 mesh, adding the particles to a reaction tube, and heating them in a low-temperature heating zone to obtain a first intermediate product;

[0082] S2, the first intermediate product enters the high-temperature heating zone for a second heating to obtain a second intermediate product;

[0083] S3, the second intermediate product enters a cooling zone for cooling to obtain a reaction product;

[0084] S4, fullerenes in the reaction product are attached to the filter along with the flue gas, the attached materials on the filter are removed, filtered, purified to obtain a purified liquid, and the solvent in the purified liquid is removed to obtain fullerenes;

[0085] During the above reaction process, nitrogen gas was continuously introduced at a flow rate of 50 sccm; the temperature of the low-temperature heating zone was 400°C, the temperature of the high-temperature heating zone was 2200°C, and the temperature of the cooling zone was 40°C;

[0086] The above filtration method is vacuum filtration, and the filter membrane is a polytetrafluoroethylene filter membrane with a pore size of 0.22 μm.

[0087] Purification was performed using high-performance liquid chromatography (HPLC). The filtrate was passed through a 5PBB column for separation. The purified solution containing fullerenes was collected and the solvent was removed by rotary evaporation to obtain the fullerenes. Chromatographic conditions were: toluene as the mobile phase at a flow rate of 0.8 mL / min, and a UV detector at a wavelength of 365 nm.

[0088] Examples 2-7

[0089] The embodiments of the method for preparing fullerenes by catalytic pyrolysis of biomass of the present invention, Examples 2-7 differ from Example 1 only in that the temperature of at least one of the low-temperature heating zone, the high-temperature heating zone, and the cooling zone is different, as shown in Table 1.

[0090] Comparative Example 1-2

[0091] Comparative Example 1-2 is a method for preparing fullerenes by catalytic pyrolysis of biomass. The only difference from Example 1 is that the temperature of at least one of the high-temperature heating zone and the cooling zone is different, as shown in Table 1.

[0092] Table 1

[0093] project Low temperature heating zone (℃) High temperature heating zone (℃) Cooling zone (℃) Example 2 300 1700 30 Example 3 600 2300 50 Example 4 400 1500 40 Example 5 400 2500 40 Example 6 400 2200 70 Example 7 400 2200 25 Comparative Example 1 400 1300 40 Comparative Example 2 400 2200 100

[0094] Examples 8-11

[0095] In the examples of the present invention for preparing fullerenes by catalytic pyrolysis of biomass, Examples 8-9 differ from Example 1 only in the nitrogen flow rate; the nitrogen flow rate in Example 8 is 30 sccm, the nitrogen flow rate in Example 9 is 70 sccm, the nitrogen flow rate in Example 10 is 10 sccm, and the nitrogen flow rate in Example 11 is 90 sccm.

[0096] Examples 12-15

[0097] In the examples of the present invention for preparing fullerenes by catalytic pyrolysis of biomass, Examples 12-15 differ from Example 1 only in that the mass ratios of the biomass material and the catalyst are different; in Example 12, the mass ratio of the biomass material and the catalyst is 1:2, in Example 13, the mass ratio of the biomass material and the catalyst is 2:1, in Example 14, the mass ratio of the biomass material and the catalyst is 1:5, and in Example 15, the mass ratio of the biomass material and the catalyst is 5:1.

[0098] Comparative Example 3

[0099] A method for preparing fullerenes by catalytic pyrolysis of biomass is different from Example 1 only in that no catalyst is used in S1.

[0100] The fullerene yields of the examples and comparative examples were tested using the following method. The test results are shown in Table 2.

[0101] Test method: After 1 hour of reaction, the feeding and heating were stopped by the method described in the embodiment and comparative example, and the attached matter was collected, filtered and purified. The purified liquid was subjected to high performance liquid chromatography, using a 5PBB column, toluene as the mobile phase, a flow rate of 0.8 mL / min, and a UV detector with a wavelength of 365 nm. The internal standard method was used to detect C 60 (retention time 11.2 min) and C 70 (retention time is 21.3min) and quantification is performed to obtain C 60 with C 70 The total concentration of C collected in this round of reaction can be calculated. 60 with C 70 The total molar amount of the biomass raw materials is used to measure the yield, and the carbon atom utilization rate in the biomass raw materials is used to measure the yield, that is, the ratio of the carbon atoms per unit mole in the biomass to the carbon atoms in the fullerenes.

[0102] Table 2

[0103]

[0104]

[0105] As shown in Table 2, the method disclosed in the present invention can produce fullerenes with a high yield, which is above 0.015%. The method is simple in process and highly controllable.

[0106] Furthermore, by comparing the test results of Examples 1-7, it was found that the fullerene yield was higher when the second heating temperature was 1700-2300°C and the cooling temperature was 30-50°C. By comparing the test results of Examples 8-11, it was found that the yield was higher than 0.03% when the carrier gas flow rate was 30-70 sccm. By comparing the test results of Examples 12-15, it was found that the yield was higher than 0.035% when the mass ratio of biomass material to catalyst was 1:2-2:1, indicating that the fullerene yield is suitable for industrial application.

[0107] Figure 3 The HPLC chromatograms of the materials after filtration and purification of the attachments in Example 1 and Comparative Example 3 show that the substance with a peak before 10 minutes is a polycyclic aromatic hydrocarbon by-product, and the substance with a peak around 11 minutes is C 60 Fullerene, the substance that emerges at around 21 minutes is C 70 Fullerene: From the above test results, it can be seen that fullerene can be prepared by the method described in this embodiment. However, if no catalyst is added, the yield of fullerene is extremely low. Figure 4 The MALDI-TOF mass spectrum of the extract of the attachment in S4 after extraction with toluene is shown in the figure. 60 Fullerenes and C 70 In addition to fullerenes, there are also large fullerenes with a molecular weight of 900-2000.

[0108] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A system for preparing fullerenes by catalytic pyrolysis of biomass, characterized in that: include: A reaction unit (1) comprises a feed inlet and a discharge outlet, wherein a low-temperature heating zone, a high-temperature heating zone, and a cooling zone are sequentially arranged adjacent to each other in the direction from the feed inlet to the discharge outlet; the reaction unit (1) is used for performing a biomass catalytic pyrolysis reaction; A temperature control unit, comprising a low-temperature heating device (2) arranged outside the low-temperature heating zone in the reaction unit (1), a high-temperature heating device (3) arranged outside the high-temperature heating zone in the reaction unit (1); and a temperature control device (4) arranged outside the cooling zone in the reaction unit (1); the temperature control unit is used to control the temperature of each zone of the reaction unit (1); A vacuum unit, comprising a vacuum cavity (5) arranged outside the reaction unit (1) and a vacuum pump group (6) for controlling the vacuum degree of the vacuum cavity (5), wherein the vacuum unit is used to provide a vacuum environment for the reaction unit (1); A feeding unit (7), connected to the feed port of the reaction unit (1), for providing reaction raw materials; A gas supply unit (8) connected to the feed port of the reaction unit (1); A collecting unit (9) is connected to the discharge port of the reaction unit (1) and is used to collect the reaction products.

2. The system for preparing fullerenes by catalytic pyrolysis of biomass according to claim 1, characterized in that: The collecting unit (9) comprises: A collecting container (10) connected to the discharge port of the reaction unit (1); A smoke filter device is connected to the top or upper side of the collection container (10), and the smoke filter device includes a filter (11) and an exhaust gas collection container (12), and the filter (11) is located between the collection container (10) and the exhaust gas collection container (12).

3. The system for preparing fullerenes by catalytic pyrolysis of biomass according to claim 2, characterized in that: The mesh size of the filter screen (11) is 200-400 meshes.

4. The system for preparing fullerenes by catalytic pyrolysis of biomass according to claim 1, characterized in that: The reaction unit (1) is one of a graphite tube, a silicon carbide tube, a corundum tube, and a boron nitride tube.

5. The system for preparing fullerenes by catalytic pyrolysis of biomass according to claim 1, characterized in that: The vacuum unit is further provided with a low-temperature heating zone temperature measuring window (13) and a high-temperature heating zone temperature measuring window (14); the low-temperature heating zone temperature measuring window (13) is provided corresponding to the low-temperature heating zone and is used to monitor the temperature of the low-temperature heating zone, and the high-temperature heating zone temperature measuring window (14) is provided corresponding to the high-temperature heating zone and is used to monitor the temperature of the high-temperature heating zone; and / or, a flow controller (15) is further provided between the gas supply unit (8) and the feed port of the reaction unit (1), and the flow controller (15) is used to control the gas flow.

6. A method for preparing fullerenes by catalytic pyrolysis of biomass, characterized in that: Prepared using the system according to any one of claims 1 to 5, comprising the following steps: S1, introducing the biomass material and the catalyst into the reaction unit (1), performing a first heating in a low-temperature heating zone to obtain a first intermediate product; S2, the first intermediate product enters a high-temperature heating zone for a second heating to obtain a second intermediate product; S3, the second intermediate product enters a cooling zone for cooling to obtain a reaction product; S4, filtering and purifying the flue gas in the reaction product to obtain the fullerene; In S1, the temperature of the first heating is 300-600° C.; in S2, the temperature of the second heating is 1500-2500° C.; in S3, the temperature of the cooling is 25-70° C.; and carrier gas is continuously introduced during the preparation of fullerene.

7. The method for preparing fullerenes by catalytic pyrolysis of biomass according to claim 6, characterized in that: In S1, the biomass material and the catalyst are first granulated separately, or the mixture of the biomass material and the catalyst is granulated, and the average particle size of the obtained particles is 40-60 mesh; and / or, in S2, the temperature of the second heating is 1700-2300°C; and / or, in S3, the temperature of the cooling is 30-50°C.

8. The method for preparing fullerenes by catalytic pyrolysis of biomass according to claim 7, characterized in that: When the length of the low-temperature heating zone in the reaction unit (1) is 3-7 cm, the length of the high-temperature heating zone is 8-12 cm, and the length of the cooling zone is 2-4 cm, the flow rate of the carrier gas is 30-70 sccm.

9. The method for preparing fullerenes by catalytic pyrolysis of biomass according to claim 6, characterized in that: The mass ratio of the biomass material to the catalyst is 1:2-2:

1.

10. The method for preparing fullerenes by catalytic pyrolysis of biomass according to claim 9, characterized in that: The biomass material is at least one of cellulose, lignin, and straw; the catalyst is at least one of zeolite molecular sieve, zirconium oxide, calcium oxide, and aluminum oxide; and the carrier gas is an inert gas.

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