Device for converting biomass tar through plasma multi-mode coupling catalyst

Abstract

The invention discloses a device for converting biomass tar by coupling plasma multi-mode with a catalyst. A plasma reactor of the device comprises a coaxial DBD body discharge structure and a structural catalyst channel internal discharge structure; the alternating-current high-voltage electrode bar, the dielectric tube and the ground electrode form coaxial DBD body discharge in an inner cavity of the dielectric tube; catalyst particles in the inner cavity of the medium tube and the structural catalyst form voltage difference at the upper end and the lower end of the structural catalyst under the combined action of an alternating-current electric field and a direct-current electric field to form discharge in a structural catalyst channel; and meanwhile, gas which flows upwards from the structural catalyst and is activated by the plasma enables catalyst particles to be in a fluidized state, and interaction between the catalyst and the plasma is realized by combining coaxial DBD discharge. The whole reaction efficiency is improved by combining direct-current and alternating-current dual-power-supply driving and fluidized bed and packed bed two-mode coupling catalysts, rapid and efficient tar treatment can be achieved, and operability and economical efficiency of the tar treatment process are improved.

Description

Technical Field

[0001] The invention relates to the technical field of plasma treatment, and in particular to a device for converting biomass tar using a plasma multi-mode coupled catalyst. Background Art

[0002] Biomass is a green, widely distributed renewable energy source that has attracted widespread attention due to its potential energy development value. Among them, gasification technology is an important way to utilize biomass energy, and has become one of the research hotspots due to its high conversion efficiency and diverse application prospects. In the gasification process, the main product, synthesis gas, is an important raw material in the field of energy and chemical industry. However, tar is inevitably generated during the gasification process. This complex organic pollutant is mainly composed of a variety of condensable hydrocarbons, including single-ring to polycyclic aromatic compounds, oxygen-containing organic matter and polycyclic aromatic hydrocarbons. The presence of tar will not only cause pipeline blockage and equipment corrosion, affecting the stability of the gasification unit, but also reduce the quality of synthesis gas and the utilization efficiency of biomass, becoming an important technical obstacle to the large-scale promotion of gasification technology.

[0003] In view of the tar problem, the current treatment technologies are mainly divided into two categories: physical purification and chemical conversion. The physical purification method reduces the tar content in the gasification gas by separating the tar from the gasification gas and transferring it to the condensed phase. It mainly includes cyclone separation, wet purification and dry purification. However, the main defect of this type of method is that it only achieves the separation of tar and fails to further transform and utilize it, resulting in the inability to effectively utilize the energy contained in the tar. At the same time, it will produce secondary pollution and reduce the energy utilization efficiency of the entire gasification process. The chemical conversion method uses high temperature conditions or catalysts to cause chemical reactions in the gasification gas to degrade it into small molecular compounds, such as H2 and CO, further reducing its content while increasing the overall energy efficiency of the biomass gasification process. Specific methods include high-temperature pyrolysis conversion and catalytic cracking conversion. Although the chemical conversion method has solved the tar conversion problem to a certain extent, its application is limited by high technical requirements. For example, high-temperature pyrolysis usually requires a reaction temperature of more than 1200°C and a long reaction time. Although the catalytic cracking technology reduces the reaction temperature, the activity, stability, selectivity and recovery performance of the catalyst are still the main bottlenecks for its promotion and application.

[0004] Prior art, publication number CN114272858B discloses a plasma catalytic system and method for efficient conversion of biomass tar, which uses a conical plasma reactor to achieve the conversion of biomass tar based on the principle of dielectric barrier discharge. In the reactor, the catalyst is placed on a flow equalizing plate, which blocks part of the airflow. Therefore, in order to achieve a better fluidization effect, a larger gas flow rate is required, and a large flow rate will reduce the residence time of the object to be treated in the plasma area, affecting the overall reaction effect. Summary of the invention

[0005] 1. Technical problems to be solved: In view of the above technical problems, the present invention provides a device for converting biomass tar with a plasma multi-mode coupled catalyst. The device is driven by a DC and AC dual power supply, and combines a fluidized bed and a packed bed mode coupled catalyst to improve the overall reaction efficiency and ensure sufficient contact between the tar and the plasma. It can not only achieve rapid and efficient treatment of the tar, but also improve the operability and economy of the tar treatment process.

[0006] 2. Technical solution: A device for converting biomass tar by plasma multi-mode coupled catalyst, characterized in that: it comprises a plasma reactor; the plasma reactor comprises a coaxial DBD body discharge structure and a structured catalyst channel discharge structure; wherein the coaxial DBD body discharge structure comprises an AC high-voltage electrode rod, a dielectric tube, and a ground electrode; the structured catalyst channel discharge structure comprises a structured catalyst, catalyst particles, a DC high-voltage electrode, and an AC high-voltage electrode; the specific connection of the above structures is as follows: The AC high-voltage electrode rod is coaxially arranged in the inner cavity of the dielectric tube; the upper end of the AC high-voltage electrode is connected to the high-voltage end of the AC power supply through a wire; a sealing ring structure is provided between the upper end of the AC high-voltage electrode rod and the dielectric tube to achieve fixed and sealed sleeve connection between the two; a coaxial plug is also provided between the middle position of the AC high-voltage electrode rod and the inner wall of the dielectric tube; the lower end of the high-voltage electrode is suspended to the upper end of the upper surface of the structured catalyst; the ground electrode is a cylindrical metal mesh structure, which is sleeved on the outer surface of the lower end of the dielectric tube; the structured catalyst is cylindrical, fixed in the inner cavity of the dielectric tube, and its interior is honeycomb-shaped, and the lower surface is fixedly connected to the DC high-voltage electrode; the upper surface of the structured catalyst is flush with the lower edge of the ground electrode; the DC high-voltage electrode is a disc with a diameter slightly smaller than that of the structured catalyst, and the upper surface of the disc is fixedly connected to the structured catalyst; the interior of the DC high-voltage electrode is mesh-shaped, and is connected to the DC high-voltage power supply through a wire; the catalyst particles are placed in the inner cavity of the dielectric tube; the upper end of the dielectric tube is provided with an air outlet, and the lower end is provided with an air intake pipe structure; The air intake pipe structure includes an air intake hard pipe and a soft pipe connected to each other. The upper end of the air intake hard pipe is fixedly connected to the lower surface of the DC high-voltage electrode, and can fix the DC high-voltage electrode and the structural catalyst at the same time. The lower end of the air intake hard pipe is connected to the gas source and the gas to be treated through the soft pipe. When the plasma reactor is powered on, the AC high-voltage electrode rod, the dielectric tube and the ground electrode form a coaxial DBD body discharge in the inner cavity of the dielectric tube; under the joint action of the AC and DC electric fields, the granular catalyst particles and the structured catalyst in the inner cavity of the dielectric tube form a voltage difference at the upper and lower ends of the structured catalyst to form a discharge in the structured catalyst channel; at the same time, the plasma-activated gas flowing upward from the structured catalyst will make the catalyst particles fluidized, and combined with the coaxial DBD body discharge, the interaction between the catalyst and the plasma is realized.

[0007] Furthermore, the medium tube is a quartz medium tube, and a wire outlet hole for passing a wire is also provided in the air inlet pipe structure at the lower end thereof.

[0008] Furthermore, the distance between the lower end of the AC high voltage electrode rod and the upper surface of the structured catalyst is 1-2 mm.

[0009] Furthermore, the sealing ring structure is a sealing ring made of polytetrafluoroethylene material, which specifically comprises a first, a second and a third sealing ring which are threadedly connected in sequence from top to bottom; wherein the center position of the first sealing ring is fixedly sleeved with an AC high-voltage electrode rod; the upper end of the third sealing ring is fixedly connected to the second sealing ring through a thread, and the lower end is fixedly sleeved to the outer wall of the upper end of the medium tube; the AC high-voltage electrode rod passes through the through holes of the center axes of the second and third sealing rings and extends into the inner cavity of the medium tube.

[0010] Furthermore, the medium tube is a quartz medium tube with a length of 160mm~220mm, an outer diameter of 12mm~19mm, an inner diameter of 10mm~16mm, and a wall thickness of 1.0~1.5mm; the outer diameter of its air inlet is 5~8mm, and the wall thickness is 0.8~1.6mm.

[0011] Furthermore, the high voltage electrode is made of stainless steel or tungsten rod with a diameter of 2-4 mm.

[0012] Furthermore, the structured catalyst has a diameter of 10 mm to 16 mm, a height of 8 mm to 20 mm, and a honeycomb aperture of 0.08-0.25 mm.

[0013] Furthermore, it also includes a high-pressure gas cylinder, a pressure reducing valve, a flow meter, a high-precision liquid sampling pump, a heating furnace, a condensation device, and an air collecting bag; the high-pressure gas cylinder, the pressure reducing valve, the flow meter, the high-precision liquid sampling pump, and the heating furnace are connected in sequence, and the heating furnace is connected to the air inlet of the plasma reactor; the air outlet of the plasma reactor is connected to the condensation device, and the air collecting bag is connected to the condensation device.

[0014] 3. Beneficial effects: (1) The method provides a device for converting biomass tar by plasma multi-mode coupled catalyst. In a coaxial DBD plasma reactor, an AC electric field is formed between an AC high voltage electrode and a ground electrode, generating a coaxial DBD discharge, and an alternating potential difference is formed between the DC high voltage electrode and the AC high voltage electrode. Since catalyst particles are placed on the structured catalyst, and there is an air layer of 1 to 2 mm between the high voltage AC electrode and the upper surface of the structured catalyst, a stable discharge plasma can be formed in the pores of the honeycomb structured catalyst under the action of the alternating electric field, forming a plasma-filled catalytic system. The gas flowing out of the honeycomb structured catalyst is not only activated by the plasma, but also causes the catalyst particles placed on the upper surface of the honeycomb structured catalyst to be in a fluidized state. Therefore, the method increases the discharge area and prolongs the contact time between the reaction gas and the plasma, while also enhancing the contact time and interaction between the plasma and the catalyst, which is beneficial to the generation of a synergistic effect between the plasma and the catalyst.

[0015] (2) The method provides a device for converting biomass tar into a plasma multi-mode coupled catalyst. In the plasma reactor, a DC power supply is used to generate a stable electric field, while an AC power supply provides an alternating electric field. Under the superposition of these two electric fields, a stable plasma discharge is formed in the pores of the honeycomb structure catalyst and inside the coaxial DBD reactor, forming two plasma coupled catalyst systems, namely, a filling system and a fluidized system, which increases the overall discharge path and enhances the interaction between the catalyst and the plasma.

[0016] (3) The plasma reactor provided by the method can realize a plasma catalytic system in a segmented packed bed mode; in the reactor, the high-voltage electrode, the dielectric tube and the ground electrode form a coaxial DBD body discharge under the drive of an AC source, and the catalyst particles stacked on the upper end of the honeycomb structure catalyst have a large dielectric constant. By superimposing a DC high voltage on the mesh electrode, an alternating potential difference can be formed at the upper and lower ends of the honeycomb structure catalyst under the joint action of the AC high-voltage electrode and the DC high-voltage electrode, thereby forming a stable discharge plasma in the pores of the honeycomb structure catalyst. At this time, the honeycomb structure catalyst is directly placed in the discharge area of ​​the plasma, forming a typical segmented packed bed plasma catalytic system.

[0017] (4) The plasma reactor provided by the method can also realize a plasma catalytic system in a fluidized bed mode; by controlling the gas flow rate of the air inlet pipe, the catalyst particles placed on the honeycomb structure catalyst can be placed in a fluidized state, forming a typical fluidized bed plasma catalytic system with the coaxial DBD body discharge.

[0018] (5) The plasma reactor in this method combines the two modes of fluidized bed and packed bed to couple the catalyst to improve the overall reaction efficiency; the reactant atmosphere will be activated by the discharge plasma formed inside the honeycomb structure catalyst channel when passing through it, and then the gas will have a higher reaction activity when it comes into contact with the small catalyst particles, which promotes the interaction between the catalyst and the plasma, thereby enhancing their synergistic effect.

[0019] In summary, this method forms a variety of coupling modes between plasma and catalyst by adjusting the electrode structure design and its excitation method, combining honeycomb structure catalysts and traditional catalyst particles. While increasing the discharge path, it also strengthens the interaction between catalyst and plasma, which is beneficial to the generation of synergistic effect between plasma and catalyst, thereby improving the overall conversion effect and performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the overall device of a device for converting biomass tar using a plasma multi-mode coupled catalyst according to the present invention; Figure 2 is an overall external view of the plasma reactor of the present invention; Figure 3 is an exploded view of the plasma reactor of the present invention; Figure 4 is a schematic diagram of a medium tube of a plasma reactor in the present invention; Figure 5 is an overall schematic diagram of the sealing structure in the present invention; Figure 6 It is a rendering of the effect in a specific embodiment.

[0021] Figure numerals: plasma reactor 1; AC high-voltage electrode rod 2; dielectric tube 3; ground electrode 4; structured catalyst 5; catalyst particles 6; DC high-voltage electrode 7; sealing ring structure 8; coaxial plug 9; air outlet 11; air inlet pipe structure 12; wire outlet 13; first sealing ring 14; second sealing ring 15; third sealing ring 16; wire 17; high-pressure gas cylinder 18; pressure reducing valve 19; flow meter 20; high-precision liquid sampling pump 21; heating furnace 22; condensing device 23; gas collecting bag 24. DETAILED DESCRIPTION

[0022] The present invention will be described in detail below with reference to the accompanying drawings.

[0023] As attached Figure 1 To Attachment Figure 5As shown, a plasma multi-mode coupled catalyst conversion device for biomass tar, characterized in that: it includes a plasma reactor 1; the plasma reactor includes a coaxial DBD body discharge structure and a structured catalyst channel discharge structure; wherein the coaxial DBD body discharge structure includes an AC high-voltage electrode rod 2, a dielectric tube 3, and a ground electrode 4; the structured catalyst channel discharge structure includes a structured catalyst 5, catalyst particles 6, a DC high-voltage electrode and an AC high-voltage electrode 7; the specific connection of the above structures is: The AC high-voltage electrode rod is coaxially arranged in the inner cavity of the dielectric tube; the upper end of the AC high-voltage electrode is connected to the high-voltage end of the AC power supply through a wire; a sealing ring structure 8 is provided between the upper end of the AC high-voltage electrode rod and the dielectric tube to achieve fixed and sealed sleeve connection between the two; a coaxial plug 9 is also provided between the middle position of the AC high-voltage electrode rod and the inner wall of the dielectric tube; the lower end of the high-voltage electrode is suspended to the upper end of the upper surface of the structured catalyst; the ground electrode is a cylindrical metal mesh structure, which is sleeved on the outer surface of the lower end of the dielectric tube; the structured catalyst is cylindrical, fixed in the inner cavity of the dielectric tube, and its interior is honeycomb-shaped, and the lower surface is fixedly connected to the DC high-voltage electrode; the structured catalyst The upper surface is flush with the lower edge of the ground electrode; the DC high-voltage electrode is a disc with a diameter slightly smaller than that of the structured catalyst, and the upper surface of the disc is fixedly connected to the structured catalyst; the interior of the DC high-voltage electrode is meshed and is connected to the DC high-voltage power supply through a wire; the catalyst particles are placed in the inner cavity of the medium tube; the upper end of the medium tube is provided with an air outlet 11, and the lower end is provided with an air intake pipe structure 12; the air intake pipe structure includes a connected air intake hard pipe and a soft pipe, the upper end of the air intake hard pipe is fixedly connected to the lower surface of the DC high-voltage electrode, and can fix the DC high-voltage electrode and the structured catalyst at the same time; the lower end of the air intake hard pipe is connected to the gas source and the gas to be treated through a soft pipe; When the plasma reactor is powered on, the AC high-voltage electrode rod, the dielectric tube and the ground electrode form a coaxial DBD body discharge in the inner cavity of the dielectric tube; under the joint action of the AC and DC electric fields, the granular catalyst particles and the structured catalyst in the inner cavity of the dielectric tube form a voltage difference at the upper and lower ends of the structured catalyst to form a discharge in the structured catalyst channel; at the same time, the plasma-activated gas flowing upward from the structured catalyst will make the catalyst particles fluidized, and combined with the coaxial DBD body discharge, the interaction between the catalyst and the plasma is realized.

[0024] Furthermore, the medium tube is a quartz medium tube, and a wire outlet hole 13 for passing a wire 17 is provided in the air inlet pipe structure at the lower end thereof.

[0025] Furthermore, the distance between the lower end of the AC high-voltage electrode rod and the upper surface of the structured catalyst is 1-2 mm.

[0026] Furthermore, the sealing ring structure is a sealing ring made of polytetrafluoroethylene material, which specifically comprises a first, a second and a third sealing ring which are threadedly connected in sequence from top to bottom; wherein the first sealing ring 14 is fixedly sleeved with an AC high-voltage electrode rod at the center position; the upper end of the third sealing ring 16 is fixedly connected to the second sealing ring 15 by a thread, and the lower end is fixedly sleeved to the outer wall of the upper end of the medium pipe; the AC high-voltage electrode rod passes through the through holes of the central axes of the second and third sealing rings and extends into the inner cavity of the medium pipe.

[0027] Furthermore, the medium tube is a quartz medium tube with a length of 160mm~220mm, an outer diameter of 12mm~19mm, an inner diameter of 10mm~16mm, and a wall thickness of 1.0~1.5mm; the outer diameter of its air inlet is 5~8mm, and the wall thickness is 0.8~1.6mm.

[0028] Furthermore, the high voltage electrode is made of stainless steel or tungsten rod with a diameter of 2-4 mm.

[0029] Furthermore, the structured catalyst has a diameter of 10 mm to 16 mm, a height of 8 mm to 20 mm, and a honeycomb aperture of 0.08-0.25 mm.

[0030] Furthermore, it also includes a high-pressure gas cylinder 18, a pressure reducing valve 19, a flow meter 20, a high-precision liquid sampling pump 21, a heating furnace 22, a condensing device 23, and an air collecting bag 24; the high-pressure gas cylinder, the pressure reducing valve, the flow meter, the high-precision liquid sampling pump, and the heating furnace are connected in sequence, and the heating furnace is connected to the air inlet of the plasma reactor; the air outlet of the plasma reactor is connected to the condensing device, and the air collecting bag is connected to the condensing device. Specific embodiment: As attached Figure 1 As shown in the figure, the whole process of using the device to process biomass tar is realized; during the process, the AC high-voltage electrode rod is connected to the high-voltage end of the AC power supply, the ground electrode is connected to the ground electrode, the DC high-voltage electrode is connected to the positive electrode of the DC power supply, and the ground electrode of the DC source is also grounded. The high-pressure gas cylinder contains N2. When the device is working, the gas cylinder is opened, and the gas blows the reaction gas into the plasma reactor along the gas pipe. The pressure reducing valve prevents the airflow from flowing back during operation, and the flow meter detects the airflow flow rate during the working state in real time. The high-precision liquid injection pump contains untreated liquid tar. When working, the heating furnace is turned on, and the tar storage bottle is opened after it reaches the set temperature, and the tar is pushed into the heating furnace. As the tar enters the heating furnace, the liquid tar will be gasified in a short time and blown into the high-voltage discharge chamber in the plasma reactor through the air inlet pipe along with the air flow. After a period of reaction, the outlet pipe valve is opened, and the treated gas enters the gas collection bag along with the air flow.

[0032] like Figures 2 to 4As shown in the figure, when the plasma reactor is working, the reaction gas enters from the inlet pipe, and the tar is cracked and converted under the joint action of plasma and catalyst to generate synthesis gas or small molecule hydrocarbon gas, which is then discharged from the outlet and can be further collected or used in other industrial processes. The design of the device achieves a good coupling between plasma and catalyst, which is conducive to the generation of synergistic effects. Combining the fluidized bed and packed bed modes, the biomass tar is processed in an efficient and stable manner, reducing its pollution and converting it into valuable chemicals.

[0033] As attached Figure 2 As shown in the figure, this reactor is used for the treatment of biomass tar. It is driven by DC and AC dual power supplies, and combines the fluidized bed and packed bed modes to couple catalysts to improve the overall reaction efficiency. The reactor is connected to an AC power supply between the AC high-voltage electrode and the ground electrode, and a dielectric barrier discharge is generated through an alternating electric field; under the superposition of the DC high-voltage electrode and the AC electric field, an alternating electric field is formed at the upper and lower ends of the honeycomb structure catalyst, generating a discharge plasma, increasing the discharge area, and prolonging the contact time between the reaction gas and the plasma. The DC power supply is used to generate a stable electric field, while the AC power supply provides an alternating electric field, increasing the discharge length in the reactor, strengthening the interaction between the catalyst and the plasma, and thus improving the reaction activity and efficiency of the plasma. The device combines the fluidized bed and packed bed modes: the honeycomb structure catalyst will generate plasma in the pores under the drive of the excitation power supply, and then a packed bed plasma system can be formed, so that the plasma and the catalyst surface contact each other, producing a synergistic effect. The catalyst particles in the reactor can form a fluidized state under the action of the airflow, and the coaxial reactor can generate a stable body discharge under the drive of the AC source, ensuring good contact between the catalyst and the plasma, stimulating more active sites on the catalyst surface, and this process provides better heat and mass transfer efficiency of the reactants, which is conducive to promoting the conversion of tar components. 17 in the figure represents a powered wire.

[0034] In order to verify the practicality of the device, the reactor of the device was compared with the conical reactor of the prior art based on methane dry reforming. During the comparison process, the flow meter was used to control the gas flow in real time to ensure that the total flow rate of CH4 and CO2 was 300 ml / min, and the volume ratio of CH4 and CO2 was 1:1. The reaction effects were analyzed and compared. The overall effect is as follows: Figure 6 As shown in the figure, Type a is a conical coaxial DBD reactor in the prior art, and Type b is a reactor structure disclosed in this scheme. It can be clearly seen from the figure that under the same working conditions, the reactor structure proposed in this scheme achieves a better reaction effect.

[0035] Although the present invention has been disclosed as above in terms of preferred embodiments, they are not intended to limit the present invention. Anyone skilled in the art can make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection defined by the claims of this application.

Claims

1. A device for converting biomass tar using plasma multi-mode coupled catalyst, characterized in that: It comprises a plasma reactor; the plasma reactor comprises a coaxial DBD body discharge structure and a structural catalyst channel discharge structure; The coaxial DBD body discharge structure includes an AC high-voltage electrode rod, a dielectric tube, and a ground electrode; the discharge structure in the structured catalyst channel includes a structured catalyst, catalyst particles, a DC high-voltage electrode and an AC high-voltage electrode; the specific connection of the above structure is: the AC high-voltage electrode rod is coaxially arranged in the inner cavity of the dielectric tube; the upper end of the AC high-voltage electrode is connected to the high-voltage end of the AC power supply through a wire; a sealing ring structure is provided between the upper end of the AC high-voltage electrode rod and the dielectric tube to achieve a fixed and sealed socket connection between the two; a coaxial plug is also provided between the middle position of the AC high-voltage electrode rod and the inner wall of the dielectric tube; the lower end of the high-voltage electrode is suspended to the upper end of the upper surface of the structured catalyst; the ground electrode is a cylindrical metal mesh structure, which is sleeved on the outer surface of the lower end of the dielectric tube; the structured catalyst is It is cylindrical and fixed in the inner cavity of the medium tube. Its interior is honeycomb-shaped, and its lower surface is fixedly connected to the DC high-voltage electrode; the upper surface of the structured catalyst is flush with the lower edge of the ground electrode; the DC high-voltage electrode is a disc with a diameter slightly smaller than that of the structured catalyst, and the upper surface of the disc is fixedly connected to the structured catalyst; the interior of the DC high-voltage electrode is mesh-shaped, and is connected to the DC high-voltage power supply through a wire; the catalyst particles are placed in the inner cavity of the medium tube; the upper end of the medium tube is provided with an air outlet, and the lower end is provided with an air intake pipe structure; the air intake pipe structure includes a connected air intake hard pipe and a soft pipe, the upper end of the air intake hard pipe is fixedly connected to the lower surface of the DC high-voltage electrode, and can fix the DC high-voltage electrode and the structured catalyst at the same time; the lower end of the air intake hard pipe is connected to the gas source and the gas to be treated through a soft pipe; When the plasma reactor is powered on, the AC high-voltage electrode rod, the dielectric tube and the ground electrode form a coaxial DBD body discharge in the inner cavity of the dielectric tube; under the joint action of the AC and DC electric fields, the granular catalyst particles and the structured catalyst in the inner cavity of the dielectric tube form a voltage difference at the upper and lower ends of the structured catalyst to form a discharge in the structured catalyst channel; at the same time, the plasma-activated gas flowing upward from the structured catalyst will make the catalyst particles fluidized, and combined with the coaxial DBD body discharge, the interaction between the catalyst and the plasma is realized.

2. The device for converting biomass tar using plasma multi-mode coupled catalyst according to claim 1, characterized in that: The medium tube is a quartz medium tube, and a wire outlet hole for passing a wire is also provided in the air inlet pipeline structure at the lower end thereof.

3. The device for converting biomass tar using plasma multi-mode coupled catalyst according to claim 1, characterized in that: The distance between the lower end of the AC high voltage electrode rod and the upper surface of the structured catalyst is 1 to 2 mm.

4. The device for converting biomass tar using plasma multi-mode coupled catalyst according to claim 1, characterized in that: The sealing ring structure is a sealing ring made of polytetrafluoroethylene material, which specifically comprises the first, second and third sealing rings which are threadedly connected in sequence from top to bottom; wherein the center position of the first sealing ring is fixedly sleeved with an AC high-voltage electrode rod; the upper end of the third sealing ring is fixedly connected to the second sealing ring through a thread, and the lower end is fixedly sleeved to the outer wall of the upper end of the medium pipe; the AC high-voltage electrode rod passes through the through holes of the center axes of the second and third sealing rings and extends into the inner cavity of the medium pipe.

5. The device for converting biomass tar using plasma multi-mode coupled catalyst according to claim 1, characterized in that: The medium tube is a quartz medium tube with a length of 160mm to 220mm, an outer diameter of 12mm to 19mm, an inner diameter of 10mm to 16mm, and a wall thickness of 1.0 to 1.5mm; the outer diameter of the air inlet is 5 to 8mm, and the wall thickness is 0.8 to 1.6mm.

6. The device for converting biomass tar using plasma multi-mode coupled catalyst according to claim 5, characterized in that: The high voltage electrode is made of stainless steel or tungsten rod, and has a diameter of 2-4 mm.

7. The device for converting biomass tar using plasma multi-mode coupled catalyst according to claim 6, characterized in that: The structured catalyst has a diameter of 10 mm to 16 mm, a height of 8 mm to 20 mm, and a honeycomb aperture of 0.08 to 0.25 mm.

8. The device for converting biomass tar using plasma multi-mode coupled catalyst according to claim 1, characterized in that: It also includes a high-pressure gas cylinder, a pressure reducing valve, a flow meter, a high-precision liquid sampling pump, a heating furnace, a condensation device, and an air collecting bag; the high-pressure gas cylinder, the pressure reducing valve, the flow meter, the high-precision liquid sampling pump, and the heating furnace are connected in sequence, and the heating furnace is connected to the air inlet of the plasma reactor; the air outlet of the plasma reactor is connected to the condensation device, and the air collecting bag is connected to the condensation device.

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