Method for simultaneously recycling VOCs (Volatile Organic Compounds) and carbon dioxide by utilizing microwaves and application of method

Abstract

The present invention relates to the technical field of VOCs treatment, and discloses a method for simultaneously recycling VOCs and carbon dioxide by using microwaves, the method comprises: contacting a gas mixture containing carbon dioxide and VOCs with a carbon fiber aggregate, and under the condition of applying microwaves to the carbon fiber aggregate, carrying out a reaction on the VOCs and the carbon dioxide to convert the VOCs and the carbon dioxide into pyrolysis gas; the carbon fiber aggregate comprises a plurality of carbon fiber basic units which are arranged in a non-directional manner, and each carbon fiber basic unit is a carbon fiber bundle formed by a single carbon fiber and / or a plurality of carbon fibers; the two ends of each carbon fiber in the length direction are carbon fiber tail ends, and the number of the carbon fiber tail ends contained in each gram of the carbon fiber aggregate is more than 1 * 10 < 6 > / g according to the number of the carbon fiber tail ends. VOCs and carbon dioxide react and are efficiently cracked into methane, ethylene, hydrogen and carbon monoxide, and the VOCs and the carbon dioxide are efficiently recycled at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of VOCs treatment, and in particular to a method for simultaneously recycling VOCs and carbon dioxide by using microwaves and an application thereof. Background Art

[0002] VOCs (volatile organic compounds) refer to a class of organic compounds with a boiling point in the range of 50 to 260 ° C under standard atmospheric pressure conditions. They mainly come from refineries, chemical industries, fuel combustion, pharmaceutical plants, automobile industries, textile manufacturers, solvent processes, cleaning products, printing presses, insulation materials and office supplies. VOCs are toxic and carcinogenic, not only causing damage to the environment, but also reacting with other atmospheric pollutants (such as NOx, SOx, etc.) to form photochemical smog, thereby destroying the ozone layer. Long-term exposure to VOCs environment poses a threat to human health and causes irreversible damage. With the acceleration of industrialization, the annual emission of VOCs has increased dramatically. According to statistics, the emission of VOCs in 2019 was about 23.4Tg. If the current control level remains unchanged, due to the rapid development of the economy, it is expected that the total amount of anthropogenic VOCs emissions in my country in 2025 will increase by 23% compared with 2019. In order to reduce the harmful effects of VOCs on the environment and humans, my country has implemented strict regulations to limit the further emission of VOCs. These regulations include requirements for monitoring, controlling and treating VOCs emission sources. In addition, VOCs treatment technology is also an important way to eliminate pollution and has attracted widespread attention.

[0003] At present, the VOCs composition in the industrial production process is extremely complex. According to the survey, the main hydrocarbon VOCs components are: 2-methylpentane, hydrogen, n-hexane, 2,2,4-trimethylpentane, n-heptane, 2,3,4-trimethylpentane, methylcyclohexane, n-octane, n-nonane, n-decane, propane, isobutane, isobutylene, n-butane, cyclopentane, isopentane, n-pentane, ethane, n-undecane, n-dodecane, methylcyclopentane, 3-methylpentane, 3-methylhexane, 2-methylhexane, 2,4-dimethylpentane, 2,2-dimethylbutane, 2,3 -Dimethylbutane, cyclohexane, 2-methylheptane, 3-methylheptane, 2,3-dimethylpentane, propylene, trans-2-butene, 1-butene, cis-2-butene, 1-pentene, cis-2-pentene, ethylene, acetylene, benzene, ethylbenzene, o-xylene, m-xylene, p-xylene, methane, toluene, m-ethyltoluene, p-ethyltoluene, o-ethyltoluene, styrene, isopropylbenzene, n-propylbenzene, 1,3,5-trimethylbenzene, 1,2,4-trimethylbenzene, 1,2,3-trimethylbenzene, m-diethylbenzene, p-diethylbenzene, acetone, 1,3-butadiene, carbon monoxide, etc.

[0004] Although these VOCs contain many chemical raw materials, the overly complex combination of components makes it difficult for petrochemical companies to effectively utilize them through gas separation. Therefore, at this stage, petrochemical companies mainly use the combustion method to treat VOCs, that is, adding combustible gas to VOCs and then fully burning them, but this method has an important problem, that is, combustion will produce carbon dioxide. Carbon dioxide is a greenhouse gas that can absorb heat from the earth's surface and gradually warm up, causing global warming. Therefore, when petrochemical companies use the combustion method to treat VOCs, it will increase the company's carbon emissions and have an adverse impact on global climate change. In addition, petrochemical companies also emit carbon dioxide during the production process. These emissions mainly come from oil processing, petrochemical production, and energy consumption. Therefore, in order to reduce carbon dioxide emissions, we hope to design a technical method that can simultaneously treat VOCs and carbon dioxide.

[0005] Plasma is the fourth state of matter besides solid, liquid and gas. Its characteristic is that the plasma state is highly dependent on the electromagnetic field. The material composition of plasma is unbound ions and free electrons, and the overall state of plasma is electrically neutral. Microwaves refer to electromagnetic waves with a wavelength between infrared and ultra-high frequency (UHF) radio waves, with very strong penetrating power. Its wavelength is between 1m and 1mm, and the corresponding frequency is 300GHz-300MHz. Microwave plasma technology is a technology that generates plasma by microwave irradiation, which can achieve an energy conversion efficiency of more than 60% under non-equilibrium plasma conditions. Microwave plasma has a significant thermal effect. The porous composite materials prepared in our Chinese invention patent application CN111099917A and Chinese invention patent application CN112823441A can generate a high temperature of more than 1000℃ by microwave irradiation in a nitrogen atmosphere, but the porous composite materials prepared in this patent are rigid structural materials, which have the disadvantages of being brittle and easy to damage.

[0006] Research has found that VOCs can be cracked into methane, ethylene, hydrogen and amorphous carbon under the action of microwave plasma at a temperature of over 1000°C, and amorphous carbon can react with carbon dioxide at a temperature of 1000°C to produce carbon monoxide. Methane, carbon monoxide and hydrogen are important energy fuels. Ethylene can be used to produce polyethylene, and hydrogen and carbon monoxide can be used to produce alkanes through Fischer-Tropsch synthesis. Therefore, the technology of converting VOCs and carbon dioxide into methane, ethylene, carbon monoxide and hydrogen at the same time has extremely high economic value and application market. Summary of the invention

[0007] To solve the problems in the prior art, the present invention provides a method for simultaneously recycling VOCs and carbon dioxide using microwaves and its application. The present invention utilizes a carbon fiber aggregate that can generate high temperature and plasma in a microwave field containing carbon dioxide gas to efficiently crack VOCs into methane, ethylene, hydrogen and amorphous carbon, and amorphous carbon and carbon dioxide can be converted into carbon monoxide at high temperature, thereby achieving efficient recycling of VOCs and carbon dioxide at the same time.

[0008] The carbon fiber aggregate used in the present invention is based on the following findings of the inventors of the present invention: carbon fiber is a material that has both high strength and flexibility. Ordinary carbon fiber, such as T300 carbon fiber monofilament, has a tensile strength of up to 3500MPa and a tensile modulus of up to 230GPa. From a physical property point of view, although it can solve the problem of high brittleness and easy damage, since carbon fiber can both absorb and reflect microwaves, and weaving carbon fiber can only prepare microwave reflective materials, such practical applications show that carbon fiber is more inclined to reflect microwaves. At present, there is no precedent for pure carbon fiber to generate plasma through microwave irradiation as a microwave heating material. Through research, the inventors of the present invention unexpectedly found that by controlling the number of carbon fiber ends contained in each gram of the carbon fiber aggregate, a carbon fiber aggregate can be obtained. Although the carbon fiber aggregate is pure carbon fiber, it can generate plasma and a high temperature of more than 1000°C under microwave irradiation.

[0009] Based on the above findings, the object of the present invention is to provide a method for simultaneously recovering VOCs and carbon dioxide using microwaves, comprising:

[0010] A mixed gas containing carbon dioxide and VOCs is brought into contact with a carbon fiber aggregate, and under the condition of applying microwaves to the carbon fiber aggregate, the VOCs react with the carbon dioxide to be converted into cracked gas;

[0011] The carbon fiber assembly comprises a plurality of randomly arranged carbon fiber basic units, wherein the carbon fiber basic unit is a single carbon fiber and / or a carbon fiber bundle formed by a plurality of carbon fibers;

[0012] The two ends of each carbon fiber in the length direction are the carbon fiber ends, and the number of carbon fiber ends contained in each gram of the carbon fiber aggregate is 1×10 6 Pieces / g or more.

[0013] Research has found that VOCs can be cracked into methane, ethylene, hydrogen and amorphous carbon under the action of microwave plasma at a temperature of over 1000°C, and amorphous carbon can react with carbon dioxide at a temperature of 1000°C to produce carbon monoxide. Methane, carbon monoxide and hydrogen are important energy fuels. Ethylene can be used to produce polyethylene, and hydrogen and carbon monoxide can be used to produce alkanes through Fischer-Tropsch synthesis. Therefore, the technology of converting VOCs and carbon dioxide into methane, ethylene, carbon monoxide and hydrogen at the same time has extremely high economic value and application market.

[0014] Through the above technical solution of the present invention, the carbon fiber aggregate is a material composed of a large number of carbon fiber ends gathered in a disordered manner, wherein plasma can be generated between the carbon fiber ends under microwave irradiation. When the mixed gas of VOCs and carbon dioxide flows through a wave-transmitting container having the carbon fiber aggregate, the carbon fiber aggregate is irradiated with microwaves, and the carbon fiber aggregate generates high temperature and plasma in a microwave field containing a carbon dioxide atmosphere. Under the combined action of high temperature and plasma, VOCs and carbon dioxide are converted into gases with carbon monoxide, methane, ethylene, and hydrogen as main components.

[0015] In a preferred embodiment of the present invention, the carbon fiber aggregate presents a two-dimensional or three-dimensional spatial structure.

[0016] In a preferred embodiment of the present invention, at least part of two or more adjacent carbon fiber basis units are in contact with each other; preferably, the contact includes at least one of abutting, overlapping and interlacing with each other.

[0017] In a preferred embodiment of the present invention, the number of carbon fiber ends contained in each gram of the carbon fiber aggregate is 1×10 6 ~6×10 8 / g, preferably 1×10 6 ~6×10 7 pcs / g, more preferably 1×10 6 ~2×10 7 Pieces / g.

[0018] In a preferred embodiment of the present invention, the carbon fiber bundle is a carbon fiber bundle filament fixed together; at least one fixed node is provided on the carbon fiber bundle filament; more preferably,

[0019] When there is only one fixed node on the carbon fiber bundle, the length of the carbon fiber bundle is 0.1 to 30 mm, preferably 1 to 20 mm, and more preferably 3 to 20 mm;

[0020] When more than two fixing nodes are provided on the carbon fiber bundle, the spacing between adjacent fixing nodes is 1 to 50 mm, preferably 2 to 30 mm, more preferably 5 to 20 mm; and part of the carbon fiber bundle between adjacent fixing nodes is in a disconnected state.

[0021] In a preferred embodiment of the present invention, the fixing includes bundling fixing and / or knotting fixing, and the fixing nodes include bundling nodes and / or knotting points. More preferably, the knotting fixing is that the carbon fiber bundles are fixed by knotting themselves; and / or the bundles of the bundling fixing are carbon fiber bundles.

[0022] The raw materials used for the carbon fiber aggregate described in the present invention can be purchased on the market. According to the present invention, the carbon fiber bundles can adopt various types of carbon fiber bundles in the prior art. In a preferred embodiment of the present invention, the carbon fiber bundles, the carbon fiber bundles for bundling, and the carbon fiber bundles for knotting are independently selected from at least one of the following types of carbon fiber bundles: T300, T700, T800, T1000, T1100, M40, M50, M60; preferably selected from at least one of the following types of carbon fiber bundles: T300, T700, T800; more preferably selected from at least one of the following types of carbon fiber bundles: T300, T700.

[0023] According to the present invention, there are multiple options for the number of carbon fibers contained in each bundle of carbon fiber bundles. In a preferred embodiment of the present invention, the number of carbon fibers contained in each bundle of carbon fiber bundles is 1K-48K, preferably 1K, 3K, 6K, 12K, 24K, 48K, more preferably 12K, 24K, and most preferably 12K.

[0024] According to the present invention, the carbon fiber assembly comprises a plurality of carbon fiber basic units arranged in an irregular manner, and the carbon fiber basic unit is a carbon fiber bundle formed by a single carbon fiber and / or a plurality of carbon fibers. In a preferred embodiment of the present invention, the carbon fiber basic unit is a carbon fiber bundle formed by a plurality of carbon fibers, or the carbon fiber basic unit comprises both a single carbon fiber and a carbon fiber bundle, or the carbon fiber basic unit is a single carbon fiber. More preferably, the carbon fiber basic unit is a carbon fiber bundle formed by a plurality of carbon fibers, or the carbon fiber basic unit comprises both a single carbon fiber and a carbon fiber bundle. In this more preferred embodiment, the carbon fiber assembly is easier to use and recycle.

[0025] In a more preferred embodiment of the present invention, when the carbon fiber basic unit contains both a single carbon fiber and a carbon fiber bundle, the total mass of the carbon fiber aggregate is 100wt%, and the content of the carbon fiber bundle in the carbon fiber aggregate is 0.1-99.9wt%, preferably 1-99wt%; and / or, the length of each fiber of the single carbon fiber is 0.1-30mm, preferably 1-20mm, more preferably 3-20mm; and / or, the diameter of the single carbon fiber is 5-10μm, and / or, the density is 1.5-2.0g / cm 3 .

[0026] The method for preparing a carbon fiber aggregate of the present invention comprises:

[0027] The single carbon fibers and / or carbon fiber bundles are assembled in a non-directional arrangement to obtain the carbon fiber aggregate; wherein the method for preparing the carbon fiber bundles includes fixing the carbon fiber bundles together and providing at least one fixed node on the carbon fiber bundles, and when more than two fixed nodes are provided on the carbon fiber bundles, the carbon fiber bundles between adjacent fixed nodes are partially disconnected or completely disconnected.

[0028] The described collection refers to the aggregation of scattered carbon fiber basic units, which are physically mixed rather than chemically connected to each other; for example, the collection of carbon fiber basic units is achieved by adopting a stacking aggregation method or a winding aggregation method, and then preferably at least two or more partially adjacent carbon fiber basic units are in contact with each other, and more preferably, at least two or more partially adjacent carbon fiber basic units are in contact with each other in at least one manner including adjacency, overlap, and interlacing.

[0029] In a preferred embodiment of the present invention, the fixing includes bundling and / or knotting.

[0030] In a preferred embodiment of the present invention, the disconnection includes cutting and / or shearing.

[0031] In a more preferred embodiment of the present invention, when there is only one fixed node on the carbon fiber bundle, the length of the carbon fiber bundle is 0.1-30 mm, preferably 1-20 mm, and more preferably 3-20 mm.

[0032] In a more preferred embodiment of the present invention, when there are more than two fixed nodes on the carbon fiber bundle, the spacing between adjacent fixed nodes is 1-50 mm, preferably 2-30 mm, and more preferably 5-20 mm.

[0033] The fixing includes bundling fixing and / or knotting fixing, and the fixing nodes include bundling nodes and / or knotting points. Preferably, the knotting fixing is performed by knotting the carbon fiber bundle itself; and / or, the bundling fixing uses the carbon fiber bundle for bundling; more preferably, the knotting method is at least one of a single knot, a flat knot, a Bollinger knot, an Alpine bow knot, an Alpine bow knot, a double Alpine bow knot, a Blake knot, a clove knot, an 8-shaped single knot, and an 8-shaped connecting knot; for the knotting method, a single knot, a flat knot, an Alpine bow knot, an Alpine bow knot, a double Alpine bow knot, an 8-shaped single knot, and an 8-shaped connecting knot are preferred. More preferably, at least one of a single knot, a flat knot, an Alpine bow knot, and an 8-shaped single knot is preferred.

[0034] The equipment used in the preparation method of the present invention is all commonly used equipment.

[0035] The above-mentioned method for preparing the carbon fiber aggregate directly uses high-strength carbon fiber as raw material. Through simple processing, a flexible, high-temperature resistant material that can generate a high temperature of more than 1000°C in a microwave field can be prepared. The process flow is simple and easy to implement, and large-scale preparation is easy.

[0036] According to the present invention, preferably, in the mixed gas containing carbon dioxide and VOCs, based on the total volume of VOCs and carbon dioxide as 100%, the content of VOCs is 10% to 90%, preferably 20% to 80%, more preferably 30% to 70%.

[0037] The amount of the carbon fiber aggregate is greater than or equal to 1% of the total mass of the mixed gas of carbon dioxide and VOCs to be treated, preferably greater than or equal to 3%, and more preferably greater than or equal to 5%.

[0038] The pyrolysis gas contains methane, ethylene, hydrogen and carbon monoxide. Preferably, in terms of volume content, taking the total volume of the pyrolysis gas as 100%, the total content of methane, ethylene, hydrogen and carbon monoxide in the pyrolysis gas is greater than 50%, preferably greater than 80%, and more preferably greater than 90%.

[0039] According to the present invention, preferably, the power of the microwave is 1W to 100KW, preferably 200W to 50KW, most preferably 500W to 20KW; and / or,

[0040] The microwave time is 0.1 to 200 min, preferably 0.5 to 150 min, most preferably 1 to 100 min; and / or,

[0041] The temperature of the carbon fiber aggregate exceeds 1000°C, causing VOCs to decompose.

[0042] According to the present invention, it is preferred that VOCs can fully contact with the carbon fiber aggregate. Specifically preferably, the mixed gas containing carbon dioxide and VOCs is contacted with the carbon fiber aggregate in the following manner: carbon dioxide and VOCs are introduced into the reactor separately or simultaneously through the pores of the carbon fiber aggregate; more preferably, carbon dioxide and VOCs are introduced separately or simultaneously from the bottom of the carbon fiber aggregate, or the carbon fiber aggregate is placed in a U-shaped container, and carbon dioxide and VOCs are introduced separately or simultaneously from one end of the U-shaped container.

[0043] According to the present invention, the VOCs, i.e., volatile organic compounds, are organic compounds having a boiling point of less than 260°C under standard atmospheric pressure conditions; preferably, the VOCs include 2-methylpentane, hydrogen, n-hexane, 2,2,4-trimethylpentane, n-heptane, 2,3,4-trimethylpentane, methylcyclohexane, n-octane, n-nonane, n-decane, propane, isobutane, isobutene, n-butane, cyclopentane, isopentane, n-pentane, ethane, n-undecane, n-dodecane, methylcyclopentane, 3-methylpentane, 3-methylhexane, 2-methylhexane, 2,4-dimethylpentane, 2,2- One or more of dimethylbutane, 2,3-dimethylbutane, cyclohexane, 2-methylheptane, 3-methylheptane, 2,3-dimethylpentane, propylene, trans-2-butene, 1-butene, cis-2-butene, 1-pentene, cis-2-pentene, ethylene, acetylene, benzene, ethylbenzene, o-xylene, m-xylene, p-xylene, methane, toluene, m-ethyltoluene, p-ethyltoluene, o-ethyltoluene, styrene, isopropylbenzene, n-propylbenzene, 1,3,5-trimethylbenzene, 1,2,4-trimethylbenzene, 1,2,3-trimethylbenzene, m-diethylbenzene, p-diethylbenzene, acetone, 1,3-butadiene, and carbon monoxide.

[0044] According to the present invention, preferably, the method for simultaneously recycling VOCs and carbon dioxide using microwaves comprises the following steps:

[0045] a. placing the carbon fiber aggregate in a sealable reaction container, wherein the material of the reaction container is a microwave transparent material;

[0046] b. introducing carbon dioxide into the reaction container to replace the air, and then introducing carbon dioxide and VOCs;

[0047] c. Start the microwave, place the reaction container under the microwave field to react, and collect the gas products generated by the reaction. Preferably: VOCs are introduced from the bottom of the carbon fiber assembly, or the carbon fiber heating material is placed in a U-shaped wave-transmitting container, and VOCs are introduced from one end of the U-shaped wave-transmitting container.

[0048] The microwave field in the method of the present invention can adopt various microwave equipment in the prior art, such as household microwave ovens, industrial microwave equipment (such as microwave thermal cracking reactors), etc.

[0049] The microwave field in the method of the present invention can adopt various microwave equipment in the prior art, such as household microwave ovens, industrial microwave equipment (such as microwave thermal cracking reactors), etc.

[0050] According to the present invention, the microwave transparent material means that microwaves can penetrate the wall of the reaction container made of the material and radiate to the sample.

[0051] The device for placing or carrying the carbon fiber aggregate in the method of the present invention can be selected from various containers or pipes in the prior art that can be penetrated by microwaves and withstand high temperatures above 1200°C, such as quartz crucibles, quartz reactors, quartz tubes, alumina crucibles, alumina reactors, alumina tubes, etc.

[0052] In the method of the present invention, VOCs are cracked and then gasified, and the gas obtained after the cracking is collected for subsequent treatment, such as being used as fuel or as a chemical industry raw material for subsequent reaction and production after gas separation.

[0053] The gas product collection is a common method in the prior art, preferably carried out under an inert atmosphere. For example, if a microwave oven is used as a microwave field, the gas collection method is as follows: in a nitrogen-protected glove box, a quartz crucible carrying waste plastics and porous composite materials is placed in a vacuum bag and sealed, and after the reaction under microwave, the crucible is unscrewed through the vacuum bag, and a syringe is used to pierce the vacuum bag for sampling; an industrial microwave oven with an air inlet and an air outlet (such as a microwave thermal cracking reactor, etc.) is used, and the gas collection method is as follows: nitrogen is purged during the reaction process, and a gas collection bag is used at the air outlet for sampling and collection.

[0054] The second aspect of the present invention is to provide an application of the method for simultaneously recovering VOCs and carbon dioxide using microwaves according to the first aspect in recovering VOCs.

[0055] The carbon fiber aggregate described in the method for simultaneously recovering VOCs and carbon dioxide using microwaves of the present invention is a material composed of a large number of carbon fiber ends gathered in a disordered manner, wherein plasma can be generated between the carbon fiber ends under microwave irradiation. The present invention obtains a carbon fiber aggregate by controlling the number of carbon fiber ends contained in each gram of the carbon fiber aggregate. Although the carbon fiber aggregate is pure carbon fiber, it can generate plasma and a high temperature of more than 1000°C under microwave irradiation. The problem of large brittleness and easy damage of porous composite materials in the prior art is overcome. In addition, the carbon fiber aggregate of the present invention has simple raw materials, is easy to prepare, and has extremely high promotion and application value.

[0056] The present invention adopts an unbreakable carbon fiber aggregate, which can generate plasma in a microwave field containing a carbon dioxide atmosphere, and efficiently crack VOCs into methane, ethylene, hydrogen and amorphous carbon. The amorphous carbon and carbon dioxide can be converted into carbon monoxide at high temperature, thereby realizing the simultaneous and efficient recycling of VOCs and carbon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a morphological photograph of the carbon fiber aggregate in Example 1 of the present invention, wherein the carbon fiber basic unit is a carbon fiber bundle prepared from carbon fiber bundle filaments. DETAILED DESCRIPTION

[0058] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the contents of the present invention still fall within the scope of protection of the present invention.

[0059] The experimental data in the examples were measured using the following instruments and measurement methods:

[0060] In the embodiment, the collected cracked gas components are subjected to chromatographic analysis in the following manner:

[0061] The gas products collected after cracking were analyzed according to ASTM D1945-14 method using a refinery gas analyzer (HPAgilent 7890A, equipped with 3 channels, including 1 FID and 2 TCDs (thermal conductivity detectors)). Hydrocarbons were analyzed on the FID channel. A TCD using a nitrogen carrier gas was used to determine the hydrogen content because there was a small difference in the conductivity of hydrogen and helium carrier gases. Another TCD using helium as a carrier gas was used to detect CO, CO2, N2 and O2. For quantitative analysis, the response factor was determined by using an RGA (refinery gas analysis) calibration gas standard.

[0062] The raw materials of the embodiments of the invention are all commercially available.

[0063] The number of carbon fiber ends contained in each gram of the carbon fiber aggregate is obtained by theoretical calculation, and the specific calculation method is:

[0064] (1) When the carbon fiber basic unit of the carbon fiber aggregate is a single carbon fiber, the number of carbon fiber ends contained in each gram of the carbon fiber aggregate corresponds to the following formula:

[0065]

[0066] N is the number of carbon fiber ends contained in each gram of the carbon fiber aggregate (unit: pieces / g), and ρ is the carbon fiber density (unit: g / cm 3 ), d is the carbon fiber diameter (unit: μm), and L is the carbon fiber filament length (unit: mm).

[0067] (2) When the carbon fiber basic unit of the carbon fiber aggregate is a carbon fiber bundle prepared from carbon fiber bundles having one or more knotting points, the number of carbon fiber ends contained in each gram of the carbon fiber aggregate is calculated as follows:

[0068] N=[(n-1)×2×t+2]×k / m

[0069] N is the number of carbon fiber ends contained in each gram of the carbon fiber aggregate (unit: pieces / g), n is the number of knotting points on the carbon fiber bundle; t is the proportion of long carbon fiber bundles cut between the knotting points, k is the number of carbon fiber roots in the carbon fiber bundle, and m is the total mass of the carbon fiber bundle (unit: g).

[0070] Take the calculation method described in Example 1 as an example. A 5000mm long T300 carbon fiber 12K bundle is tied with itself at a knotting interval of 10mm (single knot), and 499 knots can be tied. Cutting the carbon fiber at the middle position of the two ends of the knotting point by two-thirds can produce [(499-1)×2×2 / 3+2)]×12000=7992000 carbon fiber ends. The knotting point formed by the single knot is a ring without an end. The mass of the 5000mm long T300 carbon fiber 12K bundle is 3.96g. Therefore, the number of carbon fiber ends contained in each gram of the carbon fiber aggregate described in Example 1 is 7992000÷3.96g≈2×10 6 Pieces / g.

[0071] (3) For a carbon fiber aggregate prepared from carbon fiber bundles having one or more fixed nodes and / or bundled nodes, the number of carbon fiber ends contained in each gram of the carbon fiber aggregate is calculated as follows:

[0072] N=[(n-1)×2×t×k+2k+c1×n1×k1)] / m

[0073] N is the number of carbon fiber ends contained in each gram of the carbon fiber aggregate (unit: pieces / g), n is the total number of fixed nodes formed by knotting and bundling on the carbon fiber bundle; t is the proportion of the long carbon fiber bundle cut at the fixed node, and k is the number of carbon fibers in the long carbon fiber bundle;

[0074] c1 is the number of ends of each bundle of each fixed node when the fixed node is a bundling node; n1 is the number of bundling nodes; k1 is the number of carbon fiber strands contained in the bundle of the bundling node.

[0075] m is the total mass of the carbon fiber bundle (unit: g).

[0076] (4) When the carbon fiber basic unit of the carbon fiber aggregate includes both a single carbon fiber and a carbon fiber bundle, the number of carbon fiber ends contained in each gram of the carbon fiber aggregate is calculated as follows:

[0077]

[0078] N is the number of carbon fiber ends contained in each gram of the carbon fiber aggregate (unit: pieces / g), n is the total number of fixed nodes formed by knotting and bundling on the carbon fiber bundles in the part of the carbon fiber aggregate constructed with carbon fiber bundles as the basic unit; t is the proportion of the long carbon fiber bundles cut at the fixed node in the part of the carbon fiber aggregate constructed with carbon fiber bundles as the basic unit, k is the number of carbon fibers in the long carbon fiber bundles in the part of the carbon fiber aggregate constructed with carbon fiber bundles as the basic unit; c1 is the number of ends of each bundle of each fixed node in the part of the carbon fiber aggregate constructed with carbon fiber bundles as the basic unit when the fixed node is a bundling node; n1 is the number of bundling nodes in the part of the carbon fiber aggregate constructed with carbon fiber bundles as the basic unit; k1 is the number of carbon fibers containing carbon fiber bundles in the bundle of the bundling node in the part of the carbon fiber aggregate constructed with carbon fiber bundles as the basic unit; ρ is the carbon fiber density in the part of the carbon fiber aggregate constructed with a single carbon fiber as the basic unit (unit: g / cm 3 ), d is the diameter of the carbon fiber in the part constructed with a single carbon fiber as the basic unit in the carbon fiber aggregate (unit: μm), L is the length of the carbon fiber filament in the part constructed with a single carbon fiber as the basic unit in the carbon fiber aggregate (unit: mm); m1 is the total mass of the part constructed with carbon fiber bundles as the basic unit in the carbon fiber aggregate (unit: g), and m2 is the total mass of the part constructed with a single carbon fiber as the basic unit in the carbon fiber aggregate (unit: g).

[0079] Take the calculation method described in Example 5 as an example. A 2500mm long T300 carbon fiber 12K bundle is knotted by itself with a knotting spacing of 10mm (single knot), and 249 knots can be tied. Cutting two-thirds of the carbon fiber bundle at a distance of 5mm between the knotting points can produce [(249-1)×2×2 / 3+2)]×12000=3992000 carbon fiber ends. The knotting point formed by the single knot is a ring without an end. The mass of the 2500mm long T300 carbon fiber 12K bundle is 1.98g; the length is 5mm, the diameter is 7μm, and the density is 1.8g / cm 3 , the mass of a single T700 carbon fiber is 3 g, so the number of carbon fiber ends contained in each gram of the carbon fiber aggregate described in Example 5 is.

[0080]

[0081] Temperature detection method: After the microwave irradiation is completed, a metal thermocouple is immediately inserted into the reaction container and brought into contact with the carbon fiber aggregate to measure the temperature.

[0082] Preparation of carbon fiber aggregate:

[0083] Example 1

[0084] Take a 5000mm long T300 carbon fiber 12K bundle (3.96g, Weihai Guangwei Composite Materials Group Co., Ltd.), use a single knotting method, according to the knotting spacing of 10mm, to tie 499 knots. Cut two-thirds of the carbon fiber bundle at 5mm between the knotting points to make a carbon fiber aggregate. The material is rolled up and placed in a quartz jar. The number of carbon fiber ends contained in each gram of carbon fiber aggregate is about 2×10 6 At this time, the material can generate plasma and an equilibrium temperature of 1200°C under pure carbon dioxide atmosphere by 900W microwave irradiation.

[0085] Comparative Example 1

[0086] Take a 5000mm long T300 carbon fiber 12K bundle (3.96g, Weihai Guangwei Composite Materials Group Co., Ltd.), use a single knotting method, according to the knotting spacing of 250mm, to tie 19 knots. Cut two-thirds of the carbon fiber bundle at 125mm between the knotting points to make a carbon fiber aggregate, roll it up and put it in a quartz jar. The number of carbon fiber ends contained in each gram of carbon fiber aggregate is about 7.9×10 4 At this time, the material was irradiated with 900W microwaves in a pure carbon dioxide atmosphere, and the material equilibrium temperature could only reach 300°C.

[0087] Example 2

[0088] Take 4g of a single T300 carbon fiber (short carbon fiber, density 1.76g / cm) with a length of 3mm and a diameter of 7μm. 3 , Weihai Guangwei Composite Materials Group Co., Ltd.), randomly stacked in a quartz jar, and the number of carbon fiber ends contained in each gram of carbon fiber aggregate is about 9.8×10 6 At this time, the material can generate plasma and an equilibrium temperature of 1400°C under pure carbon dioxide atmosphere by 1200W microwave irradiation.

[0089] Comparative Example 2

[0090] Take 4g of a single T300 carbon fiber (short carbon fiber, density 1.76g / cm) with a length of 60mm and a diameter of 7μm. 3 , Weihai Guangwei Composite Materials Group Co., Ltd.), randomly stacked in a quartz jar, and the number of carbon fiber ends per gram of carbon fiber aggregate is about 4.9×10 5 At this time, the material was irradiated with 1200W microwaves in a pure carbon dioxide atmosphere, and the material temperature could only reach an equilibrium temperature of 600°C.

[0091] Example 3

[0092] Take a 5600mm long T700 carbon fiber 12K bundle (4.48g, diameter 7μm, Weihai Guangwei Composite Materials Group Co., Ltd.), use a single knotting method, according to the knotting spacing of 14mm, to tie 399 knots. Cut two-thirds of the carbon fiber bundle at 7mm from the middle of the knotting point to make a carbon fiber aggregate. The material is rolled up and placed in a quartz jar. The number of carbon fiber ends contained in each gram of carbon fiber aggregate is about 1.4×10 6 At this time, the material can generate plasma and an equilibrium temperature of 1100°C by 700W microwave irradiation in a mixed gas atmosphere of carbon dioxide and water vapor with a volume ratio of 90:10.

[0093] Comparative Example 3

[0094] Take a 5000mm long T700 carbon fiber 12K bundle (4.0g, Weihai Guangwei Composite Materials Group Co., Ltd.), use a single knotting method, according to the knotting spacing of 250mm, and tie 19 knots. Cut two-thirds of the carbon fiber bundle at 125mm between the knotting points to make a carbon fiber aggregate, roll it up and put it in a quartz jar. The number of carbon fiber ends contained in each gram of carbon fiber aggregate is about 7.8×10 4 At this time, the material was irradiated with 700W microwaves in a mixed gas atmosphere of carbon dioxide and water vapor with a volume ratio of 90:10, and the material equilibrium temperature could only reach 100°C.

[0095] Example 4

[0096] Take 6g of T700 single carbon fiber (short carbon fiber, density 1.8g / cm) with a length of 5mm and a diameter of 7μm 3 , Weihai Guangwei Composite Materials Group Co., Ltd.), randomly stacked in a quartz jar, and the number of carbon fiber ends per gram of carbon fiber aggregate is about 5.8×10 6At this time, the material can generate plasma and an equilibrium temperature of 1050°C by 1200W microwave irradiation in a mixed gas atmosphere of carbon dioxide and water vapor with a volume ratio of 30:70.

[0097] Comparative Example 4

[0098] Take 6g of T700 single carbon fiber (short carbon fiber, density 1.8g / cm) with a length of 35mm and a diameter of 7μm 3 , Weihai Guangwei Composite Materials Group Co., Ltd.), randomly stacked in a quartz jar, and the number of carbon fiber ends per gram of carbon fiber aggregate is about 8.3×10 5 At this time, the material was irradiated with 1200W microwave in a mixed gas atmosphere with a volume ratio of carbon dioxide and water vapor of 30:70, and the material equilibrium temperature could only reach 900℃.

[0099] Example 5

[0100] Take a 2500mm long T300 carbon fiber 12K bundle (1.98g, Weihai Guangwei Composite Materials Group Co., Ltd.), use a single knotting method, according to the knotting spacing of 10mm, to tie 249 knots. Cut two-thirds of the carbon fiber bundle at 5mm between the knotting points; take 3g of a single T700 carbon fiber (short carbon fiber, density 1.8g / cm 3 , Weihai Guangwei Composite Materials Group Co., Ltd.), mixed with knotted carbon fiber bundles to form carbon fiber aggregates, which were randomly stacked in a quartz tank. The number of carbon fiber ends per gram of carbon fiber aggregate per unit mass was about 4.3×10 6 At this time, the material can generate plasma and an equilibrium temperature of 1280°C under pure carbon dioxide atmosphere by 900W microwave irradiation.

[0101] The carbon fiber aggregates prepared in Examples 1-5 have a number of carbon fiber ends greater than 1×10 6 / g, sufficient plasma can be generated under microwave irradiation in pure carbon dioxide and mixed gas (carbon dioxide and water vapor) atmosphere, so that the material equilibrium temperature is greater than 1000°C. The carbon fiber aggregates prepared in Comparative Examples 1-4 have a carbon fiber end number per gram of carbon fiber aggregate less than 1×10 6 / g, and sufficient plasma cannot be generated under microwave irradiation in the atmosphere of pure carbon dioxide and mixed gas (carbon dioxide and water vapor), so that the material equilibrium temperature is less than 900℃.

[0102] Using microwaves to simultaneously recycle VOCs and carbon dioxide:

[0103] VOCs gas was collected from a number of refineries and carbon dioxide was introduced to prepare five samples with a volume ratio of VOCs to carbon dioxide of 30:70, 40:60, 50:50, 60:40, and 70:30.

[0104] Example 6

[0105] The surface of the carbon fiber aggregate obtained by 4g Example 1 is placed in a quartz tank, and there are vents below and above the quartz tube, respectively, so that the mixed gas of VOCs and carbon dioxide enters from the lower port and flows out from the upper port after contacting the carbon fiber microwave material (i.e., carbon fiber aggregate). First, the quartz tank is purged under a pure carbon dioxide atmosphere to exclude the air inside, and then sample 1 is introduced at a flow rate of 40ml / min, and a total of 80g of mixed gas is introduced, and an industrial microwave oven is used to perform microwave irradiation with a microwave power of 700W, and a gas collection bag is used to collect the gas phase products produced after microwave cracking, and the gas phase composition of sample 1 and sample 1 cracking product is analyzed by gas chromatography, as shown in Table 1.

[0106] The volume fraction of carbon dioxide in the cracking product gas of Sample 1 was reduced from 50% to 0%. At the same time, the other 19 VOCs were converted into four substances: methane (19.53 Vol%), ethylene (33.32 Vol%), hydrogen (31.07 Vol%) and carbon monoxide (16.08 Vol%), which greatly reduced the difficulty of recycling VOCs.

[0107] The carbon fiber aggregates obtained in Examples 2-5 were subjected to the same experiment as above, and similar experimental phenomena and results were obtained.

[0108] Table 1. Gas phase composition of sample 1 and microwave plasma cracking products of sample 1

[0109]

[0110]

[0111] Example 7

[0112] 12g of the carbon fiber aggregate obtained in Example 1 was placed in a U-shaped tube with a tube length of 40cm, so that the mixed gas of VOCs and carbon dioxide flowed in from one end of the U-shaped quartz tube, contacted with the carbon fiber microwave material, and then flowed out from the other end. The U-shaped quartz tube with the carbon fiber aggregate added was placed in an industrial microwave oven, and the quartz tank was first purged under a pure carbon dioxide atmosphere to remove the air inside, and then sample 2 was introduced at a flow rate of 20ml / min, and a total of 200g of mixed gas was introduced, and an industrial microwave oven was used to perform microwave irradiation at a microwave power of 350W, and a gas collection bag was used to collect the gas phase products produced after microwave cracking, and the gas phase composition of sample 2 and the cracking product of sample 2 was analyzed by gas chromatography, as shown in Table 2.

[0113] The volume fraction of carbon dioxide in the cracking product gas of sample 2 was reduced from 30% to 0%, while the other 17 VOCs were converted into four substances: methane (11.25Vol%), ethylene (36.61Vol%), hydrogen (32.44Vol%) and carbon monoxide (19.7Vol%).

[0114] Table 2. Gas phase composition of sample 2 and microwave plasma cracking products of sample 2

[0115]

[0116] Example 8

[0117] The other conditions were the same as those in Example 6, except that Sample 1 was replaced by Sample 3, which was introduced at a flow rate of 80 ml / min, a total of 40 g of mixed gas was introduced, and microwave irradiation was performed at a power of 1500 W in an industrial microwave oven. A gas collecting bag was used to collect the gas phase products produced after microwave cracking, and the gas phase compositions of Sample 3 and the cracking products of Sample 3 were analyzed by gas chromatography, as shown in Table 3.

[0118] The volume fraction of carbon dioxide in the cracking product gas of sample 3 was reduced from 70% to 0%, while the other 22 VOCs were converted into four substances: methane (20.78Vol%), ethylene (20.52Vol%), hydrogen (23Vol%) and carbon monoxide (35.7Vol%).

[0119] Table 1. Gas phase composition of sample 3 and microwave plasma cracking products of sample 3

[0120]

[0121] Example 9

[0122] The other conditions were the same as those in Example 7, except that Sample 2 was replaced by Sample 4, and the mixed gas was introduced at a flow rate of 60 ml / min, with a total of 150 g of mixed gas introduced. The industrial microwave oven was used for microwave irradiation at a power of 900 W, and a gas collecting bag was used to collect the gas phase products produced after microwave cracking. The gas phase compositions of Sample 4 and the cracking products of Sample 4 were analyzed by gas chromatography, as shown in Table 4.

[0123] The volume fraction of carbon dioxide in the cracking product gas of sample 4 was reduced from 40% to 0%, while the other 19 VOCs were converted into four substances: methane (18.69Vol%), ethylene (30.45Vol%), hydrogen (30.79Vol%) and carbon monoxide (20.07Vol%).

[0124] Table 4. Gas phase composition of sample 4 and microwave plasma cracking products of sample 4

[0125]

[0126]

[0127] Example 10

[0128] The other conditions were the same as those in Example 7, except that Sample 2 was replaced by Sample 5, and the mixed gas was introduced at a flow rate of 120 ml / min, with a total of 240 g of mixed gas introduced. The industrial microwave oven was used for microwave irradiation at a power of 1500 W, and a gas collecting bag was used to collect the gas phase products produced after microwave cracking. The gas phase compositions of Sample 5 and the cracking products of Sample 5 were analyzed by gas chromatography, as shown in Table 5.

[0129] The volume fraction of carbon dioxide in the cracking product gas of sample 5 was reduced from 60% to 0%, while the other 18 VOCs were converted into four substances: methane (19.29 Vol%), ethylene (21.78 Vol%), hydrogen (28.05 Vol%) and carbon monoxide (30.88 Vol%).

[0130] Table 5. Gas phase composition of sample 5 and microwave plasma cracking products of sample 5

[0131]

[0132]

[0133] The experimental results in Tables 1-5 show that through the plasma treatment generated by the carbon fiber aggregate, the carbon dioxide in the samples is fully consumed, and the complex VOCs components are converted into methane, ethylene, hydrogen, and carbon monoxide, which greatly reduces the difficulty of recycling VOCs.

[0134] Comparative Example 5

[0135] The 4 g of carbon fiber aggregate obtained in Example 1 used in Example 6 was replaced by 4 g of silicon carbide powder. The other conditions were the same as in Example 6. A gas collecting bag was used to collect the gas phase products produced after microwave cracking, and the gas phase composition of sample 1 and the cracking product of sample 1 was analyzed by gas chromatography, as shown in Table 6.

[0136] Since silicon carbide cannot generate microwave plasma and its heating temperature cannot exceed 1000°C, the volume fraction of carbon dioxide is only reduced by 10%, and the VOCs components increase from 19 to 25, making the VOCs components more complex and difficult to use. It can be seen that carbon fiber aggregates are the key to achieving efficient recycling of VOCs and carbon dioxide at the same time.

[0137] Table 6. Gas phase composition of sample 1 and silicon carbide microwave pyrolysis products of sample 1

[0138]

[0139]

[0140] Comparative Example 6

[0141] 50 vol% of carbon dioxide in sample 1 in Example 6 was replaced by 50 vol% of nitrogen, and the other conditions were the same as in Example 6. During the cracking process, there was no microwave plasma generated by carbon dioxide to consume the amorphous carbon formed by VOCs at high temperature, resulting in the amorphous carbon gradually covering and bonding the ends of the carbon fibers together, causing the number of carbon fiber ends that can generate plasma to decrease rapidly, and eventually leading to the failure of the carbon fiber aggregate. It can be seen that the addition of carbon dioxide is crucial to stabilizing the microwave cracking system.

[0142] Comparative Example 7

[0143] 4 g of the carbon fiber aggregate obtained in Example 1 used in Example 6 was replaced by 4 g of the carbon fiber aggregate obtained in Comparative Example 1. Other conditions were the same as in Example 6. A gas collecting bag was used to collect the gas phase products produced after microwave pyrolysis, and the gas phase composition of Sample 1 and the pyrolysis product of Sample 1 was analyzed by gas chromatography, as shown in Table 7.

[0144] Since the temperature of the carbon fiber aggregate obtained in Comparative Example 1 can only reach 300°C under carbon dioxide microwave irradiation, carbon dioxide and VOCs cannot react at this temperature, so the products before and after pyrolysis in Table 7 do not change. It can be seen that the number of carbon fiber ends contained in each gram of carbon fiber aggregate must reach 1×10 6 / g or more to deal with VOCs and carbon dioxide.

[0145] Table 7. Gas phase composition of microwave pyrolysis products of carbon fiber aggregates of Sample 1 and Comparative Example 1

[0146]

[0147] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

[0148] All publications, patent applications, patents and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings conventionally understood by those skilled in the art. In the event of a conflict, the definition in this specification shall prevail.

[0149] When this specification uses the prefix "well-known to those skilled in the art", "prior art" or similar terms to introduce materials, substances, methods, steps, devices or components, etc., the objects introduced by the prefix cover those commonly used in the art when this application is filed, but also include those that are not commonly used at present but will become recognized in the art as being suitable for similar purposes.

[0150] The endpoints and any values ​​of the scope disclosed in the present application document are not limited to the precise scope or value, and these scopes or values ​​should be understood to include values ​​close to these scopes or values. For numerical ranges, between the endpoint values ​​of each scope, between the endpoint values ​​of each scope and a separate point value, and between separate point values, one or more new numerical ranges can be combined with each other, and these numerical ranges should be considered as specifically disclosed in this article. Hereinafter, in principle, each technical solution can be combined with each other to obtain a new technical solution, which should also be considered as specifically disclosed in this article.

[0151] In the context of the present specification, any matters or items not mentioned are directly applicable to those known in the art without any changes except those explicitly stated.

[0152] Moreover, any embodiment described in this document may be freely combined with one or more other embodiments described in this document, and the technical solutions or technical ideas formed thereby are deemed to be part of the original disclosure or original record of the present invention, and should not be regarded as new content that has not been disclosed or anticipated in this document, unless a person skilled in the art considers that the combination is obviously unreasonable.

Claims

1. A method for simultaneously recovering VOCs and carbon dioxide using microwaves, comprising: A mixed gas containing carbon dioxide and VOCs is brought into contact with a carbon fiber aggregate, and under the condition of applying microwaves to the carbon fiber aggregate, the VOCs react with the carbon dioxide to be converted into cracked gas; The carbon fiber assembly comprises a plurality of randomly arranged carbon fiber basic units, wherein the carbon fiber basic unit is a single carbon fiber and / or a carbon fiber bundle formed by a plurality of carbon fibers; The two ends of each carbon fiber in the length direction are the carbon fiber ends, and the number of carbon fiber ends contained in each gram of the carbon fiber aggregate is 1×10 6 Pieces / g or more.

2. The method according to claim 1, characterized in that: The carbon fiber basic unit is a carbon fiber bundle formed by multiple carbon fibers, or the carbon fiber basic unit contains both a single carbon fiber and a carbon fiber bundle, or the carbon fiber basic unit is a single carbon fiber; preferably, When the carbon fiber basic unit comprises both a single carbon fiber and a carbon fiber bundle, the content of the carbon fiber bundle in the carbon fiber aggregate is 0.1-99.9wt%, preferably 1-99wt%, based on the total mass of the carbon fiber aggregate being 100wt%; and / or The length of each single carbon fiber is 0.1-30 mm, preferably 1-20 mm, and more preferably 3-20 mm.

3. The method according to claim 1, characterized in that: The carbon fiber aggregate presents a two-dimensional or three-dimensional spatial structure; and / or, At least some of two or more adjacent carbon fiber base units are in contact with each other; and / or, Calculated by the number of carbon fiber ends, the number of carbon fiber ends contained in each gram of the carbon fiber aggregate is 1×10 6 ~6×10 8 / g, preferably 1×10 6 ~6×10 7 pcs / g, more preferably 1×10 6 ~2×10 7 Pieces / g.

4. The method according to claim 1, characterized in that: The carbon fiber bundle is a carbon fiber bundle filament fixed together; at least one fixed node is provided on the carbon fiber bundle filament; preferably, When there is only one fixed node on the carbon fiber bundle, the length of the carbon fiber bundle is 0.1 to 30 mm, preferably 1 to 20 mm, and more preferably 3 to 20 mm; When the carbon fiber bundle is provided with more than two fixed nodes, the spacing between adjacent fixed nodes is 1 to 50 mm, preferably 2 to 30 mm, more preferably 5 to 20 mm; and part of the carbon fiber bundle between adjacent fixed nodes is disconnected; and / or, The fixing includes bundling fixing and / or knotting fixing, and the fixing nodes include bundling nodes and / or knotting points. More preferably, the knotting fixing is that the carbon fiber bundles are fixed by knotting themselves; and / or the bundles of the bundling fixing are carbon fiber bundles.

5. The method according to claim 4, characterized in that: The carbon fiber bundles, the carbon fiber bundles for bundling, and the carbon fiber bundles for knotting are independently selected from at least one of the following types of carbon fiber bundles: T300, T700, T800, T1000, T1100, M40, M50, and M60; preferably selected from at least one of the following types of carbon fiber bundles: T300, T700, and T800; more preferably selected from at least one of the following types of carbon fiber bundles: T300 and T700.

6. The method according to claim 5, characterized in that: The number of carbon fibers contained in each bundle of carbon fiber filaments is 1K-48K, preferably 1K, 3K, 6K, 12K, 24K, 48K, and more preferably 12K, 24K.

7. The method according to claim 1, characterized in that: In the mixed gas containing carbon dioxide and VOCs, the content of VOCs is 10% to 90%, preferably 20% to 80%, more preferably 30% to 70%, based on the total volume of VOCs and carbon dioxide being 100%; and / or, The amount of the carbon fiber aggregate is greater than or equal to 1% of the total mass of the carbon dioxide and VOCs mixed gas to be treated, preferably greater than or equal to 3%, more preferably greater than or equal to 5%; and / or, The cracked gas contains methane, ethylene, hydrogen and carbon monoxide.

8. The method according to claim 1, characterized in that: The power of the microwave is 1W to 100KW, preferably 200W to 50KW, most preferably 500W to 20KW; and / or, The microwave time is 0.1 to 200 min, preferably 0.5 to 150 min, most preferably 1 to 100 min; and / or, The temperature of the carbon fiber aggregate exceeds 1000°C, causing VOCs to decompose.

9. The method according to claim 1, characterized in that: The contacting method of the mixed gas containing carbon dioxide and VOCs with the carbon fiber aggregate includes: introducing carbon dioxide and VOCs into the reactor through the pores of the carbon fiber aggregate separately or simultaneously; preferably, Carbon dioxide and VOCs are introduced separately or simultaneously from the bottom of the carbon fiber aggregate, or the carbon fiber aggregate is placed in a U-shaped container, and carbon dioxide and VOCs are introduced separately or simultaneously from one end of the U-shaped container.

10. The method according to claim 1, characterized in that: The VOCs are organic compounds with a boiling point of less than 260°C under standard atmospheric pressure conditions; preferably, the VOCs include 2-methylpentane, hydrogen, n-hexane, 2,2,4-trimethylpentane, n-heptane, 2,3,4-trimethylpentane, methylcyclohexane, n-octane, n-nonane, n-decane, propane, isobutane, isobutylene, n-butane, cyclopentane, isopentane, n-pentane, ethane, n-undecane, n-dodecane, methylcyclopentane, 3-methylpentane, 3-methylhexane, 2-methylhexane, 2,4-dimethylpentane, 2,2-dimethylbutane, 2,3 - one or more of dimethylbutane, cyclohexane, 2-methylheptane, 3-methylheptane, 2,3-dimethylpentane, propylene, trans-2-butene, 1-butene, cis-2-butene, 1-pentene, cis-2-pentene, ethylene, acetylene, benzene, ethylbenzene, o-xylene, m-xylene, p-xylene, methane, toluene, m-ethyltoluene, p-ethyltoluene, o-ethyltoluene, styrene, isopropylbenzene, n-propylbenzene, 1,3,5-trimethylbenzene, 1,2,4-trimethylbenzene, 1,2,3-trimethylbenzene, m-diethylbenzene, p-diethylbenzene, acetone, 1,3-butadiene, and carbon monoxide.

11. The method according to any one of claims 1 to 10, characterized in that The following steps are involved: a. placing the carbon fiber aggregate in a sealable reaction container, wherein the material of the reaction container is a microwave transparent material; b. introducing carbon dioxide into the reaction container to replace the air, and then introducing carbon dioxide and VOCs; c. Start the microwave, place the reaction container under the microwave field to react, and collect the gas products generated by the reaction.

12. Use of the method for simultaneously recovering VOCs and carbon dioxide using microwaves according to any one of claims 1 to 11 in recovering VOCs.

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