A biomass tar fractionating plasma catalytic system and method of use thereof

Abstract

The application discloses a biomass tar grading plasma catalysis system and a use method thereof, and belongs to the technical field of biomass tar treatment. The biomass tar grading plasma catalysis system comprises a high-voltage power supply, a heating furnace, a reactor and a temperature control system. The heating furnace is divided into an upper heating furnace and a lower heating furnace. The reactor is divided into a plasma catalysis zone and a thermal catalysis zone from top to bottom. The upper heating furnace is coated outside the plasma catalysis zone. The lower heating furnace is coated outside the thermal catalysis zone. The temperature control system is connected with the upper heating furnace and the lower heating furnace respectively. The high-voltage power supply is connected with the plasma catalysis zone. The upper and lower heating furnaces can solve the temperature setting contradiction in a single-stage plasma catalysis system caused by the fact that the plasma discharge intensity decreases with the increase of temperature and the catalytic activity of the catalyst increases with the increase of temperature. The honeycomb coal-shaped multiple corundum tube reactors in parallel connection are adopted in the plasma discharge section, so that the treatment capacity is improved and the treatment efficiency is improved under the premise of ensuring the appropriate discharge gap between the high-voltage electrode and the low-voltage electrode.

Description

TECHNICAL FIELD

[0001] The present application relates to a biomass tar catalytic system and method, in particular to a biomass tar hierarchical plasma catalytic system and a method thereof. BACKGROUND

[0002] Biomass is a carbon-neutral fuel, and its efficient and clean use will help China achieve the "double carbon" goal smoothly. The synthesis gas produced by biomass gasification can be directly used as raw material for the synthesis of liquid fuel, or can be used to prepare high-value-added chemicals, which has great application potential. However, the gasification by-product tar has always been a bottleneck restricting its industrial application. Tar can be generally considered as a general term for organic compounds with a molecular weight greater than benzene, which can adhere to the gasification reactor pipe or other gas equipment after condensation, causing energy waste and safety threats. Therefore, developing an efficient and economical tar removal method has become the focus of researchers. Tar removal methods mainly include physical removal, thermal conversion, catalytic conversion, plasma conversion, etc.

[0003] The better technology in the prior art is catalytic conversion and low-temperature plasma conversion. The advantage of catalytic conversion is high selectivity of conversion products, but the activity of general transition metal catalysts is weak, and the ability to break chemical bonds in tar molecules is insufficient. Low-temperature plasma technology has high activity due to its high-energy particles, but the product selectivity is weak. Low-temperature plasma coupled catalytic technology will complement the advantages of the two technologies, and has great application potential. However, the low-temperature plasma coupled catalytic system also has certain deficiencies: 1) The distance between the high-voltage electrode and the low-voltage electrode cannot be too large, which leads to difficulties in equipment scaling, and therefore the gas processing capacity is low; 2) The discharge intensity of low-temperature plasma decreases with the increase of temperature, and the activity of the catalyst increases with the increase of temperature, which leads to a contradiction in temperature selection for a single-stage low-temperature plasma coupled catalytic system. SUMMARY

[0004] The purpose of the present application is to provide a hierarchical plasma catalytic system that avoids the contradiction between plasma and temperature during biomass tar catalysis.

[0005] Technical solution: The biomass tar hierarchical plasma catalytic system provided by the present application comprises a high-voltage power supply, a heating furnace, a reactor, and a temperature control system; wherein the heating furnace is divided into an upper heating furnace and a lower heating furnace, the reactor is divided into a plasma catalytic zone and a thermal catalytic zone from top to bottom, the upper heating furnace is wrapped outside the plasma catalytic zone, the lower heating furnace is wrapped outside the thermal catalytic zone, and the temperature control system is connected with the upper heating furnace and the lower heating furnace respectively, and the high-voltage power supply is connected with the plasma catalytic zone.

[0006] Further, the reactor is provided with an upper cover and a lower cover at the upper and lower ends respectively, the upper cover is provided with a wiring port, and the lower cover is provided with an air outlet; the reactor is provided with an air inlet on the upper end side; the reactor is provided with a boss for separating the reactor into a plasma catalytic zone and a thermal catalytic zone, a corundum tube unit is installed above the boss, a high-voltage electrode unit is arranged inside the corundum tube unit, and the thermal catalytic zone is provided with a baffle for placing a catalyst.

[0007] Further, the corundum tube unit comprises a plurality of corundum tubes, a low-voltage electrode and a support plate, the corundum tubes are fixedly installed on the support plate, the support plate is placed on the boss, and the low-voltage electrode is wrapped around the corundum tubes; the connecting plate is provided with a wiring post for converging high-voltage electrode wires, and the wiring post is connected with a high-voltage power supply through the wiring port.

[0008] Further, the high-voltage electrode unit comprises a plurality of high-voltage electrodes and catalyst gaskets, the high-voltage electrodes are fixedly installed with connecting plates at the upper ends, the high-voltage electrodes are installed one-to-one corresponding to the corundum tubes, and the high-voltage electrodes are connected with a high-voltage power supply; the catalyst gaskets are fixedly installed at the lower ends of the high-voltage electrodes.

[0009] Further, the shell is a quartz tube.

[0010] Further, the corundum tubes are distributed on the support plate in a honeycomb coal shape.

[0011] Further, the corundum tubes are provided with sealing plates at the upper ports.

[0012] Further, the low-voltage electrode is a metal mesh.

[0013] Further, the reactor is provided with a wire outlet on the upper side, and the low-voltage electrode is grounded through the wire outlet.

[0014] A use method of the above biomass tar grading plasma catalytic system, comprising the following steps:

[0015] (1) Start the heating furnace, and set the temperature of the upper and lower heating furnaces according to the characteristics of the gas to be treated;

[0016] (2) Turn on the high-voltage power supply, set the current parameters, and form a stable and reliable discharge plasma;

[0017] (3) Introduce biomass gasification synthesis gas into the air inlet, adjust the air inlet amount, and make the gas flow uniform and stable through the discharge area and the catalyst area;

[0018] (4) Collect the treated biomass gasification synthesis gas from the air outlet;

[0019] (5) After the gas treatment is completed, stop the introduction of biomass gasification synthesis gas, turn off the heating furnace and the high-voltage power supply, and stop collecting the gas, and the system operation is completed.

[0020] Advantages: Compared with the prior art, the present application has the following remarkable advantages:

[0021] (1) The present application sets up upper and lower heating furnaces to solve the temperature setting contradiction in a single-stage plasma catalytic system caused by the decrease of plasma discharge intensity with the increase of temperature and the increase of catalyst catalytic activity with the increase of temperature.

[0022] (2) The present application adopts the parallel mode of the honeycomb coal-like multiple corundum tube reactors in the plasma discharge section to improve the processing capacity and efficiency under the premise of ensuring the appropriate discharge gap between the high-voltage electrode and the low-voltage electrode, and solves the problem of low processing capacity caused by the too large discharge gap between the high-voltage electrode and the low-voltage electrode of a single reactor.

[0023] (3) The present application has uniform and stable plasma discharge, simple reaction device, convenient installation, high processing efficiency, and obvious synergistic effect of low-temperature plasma and catalyst in the process of tar removal.

[0024] (4) The catalyst used in the present application is not limited, such as Ni / Al2O3, Fe / Al2O3, Ni-Fe / Al2O3, Ni / HAP (hydroxyapatite), Fe / HAP, Ni-Fe / HAP, etc. can be used.

[0025] (5) The present application can effectively remove by-product tar and improve the quality of biomass gasification synthesis gas when combined with biomass gasification technology. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic diagram of the overall structure of the system of the present application;

[0027] Figure 2 is a schematic diagram of the reactor of the present application;

[0028] Figure 3 is an exploded view of the reactor of the present application;

[0029] Figure 4 is a top view and A-A sectional view of the reactor of the present application;

[0030] Figure 5 is a front view and top view of the corundum tube unit of the present application;

[0031] Figure 6 is a front view and bottom view of the high-voltage electrode unit of the present application. DETAILED DESCRIPTION

[0032] The technical solutions of the present application will be further described below in conjunction with the drawings.

[0033] For example, Figures 1 to 6As shown, the application provides a biomass tar staged plasma catalytic system, a high-voltage power supply 1, a heating furnace 2, a reactor 3 and a temperature control system 4. The heating furnace 2 is divided into an upper heating furnace 201 and a lower heating furnace 202, and the temperature control system 4 is connected with the upper heating furnace 201 and the lower heating furnace 202 respectively. The reactor 3 is divided into a plasma catalytic zone 301 and a thermal catalytic zone 302 from top to bottom, and the plasma catalytic zone 301 is heated by the upper heating furnace 201, and the thermal catalytic zone 302 is heated by the lower heating furnace 202.

[0034] The reactor 3 is provided with a corundum tube unit 5 and a baffle 6. The reactor 3 is a quartz tube, and the upper end and the lower end of the reactor 3 are respectively provided with an upper cover 7 and a lower cover 8. The upper cover 7 is provided with a wiring port 9 in the middle. The lower cover 8 is provided with an air outlet 10 in the middle. The upper end of the reactor 3 is provided with an air inlet 11 on the side surface. A boss 12 located in the middle of the reactor 3 divides the reactor 3 into the plasma catalytic zone 301 and the thermal catalytic zone 302. The boss 12 is provided with the corundum tube unit 5, and the corundum tube unit 5 is provided with a high-voltage electrode unit 13. The corundum tube unit 5 and the high-voltage electrode unit 13 form the upper plasma catalytic zone 301. The corundum tube unit 5 is provided with a sealing plate 14 above. The other side surface of the upper end of the reactor 3 is provided with a wire outlet 15. The thermal catalytic zone is provided with the baffle 6 for placing catalysts in the middle.

[0035] The corundum tube unit 5 includes a plurality of corundum tubes 16, a low-voltage electrode 17 and a support plate 18. The corundum tubes 16 are fixedly installed on the support plate 18 and are distributed in a honeycomb coal shape. The support plate 18 is clamped above the boss 12. The low-voltage electrode 17 is a metal wire mesh wrapped outside the corundum tube 16 and is grounded through the wire outlet 15.

[0036] The high-voltage electrode unit 13 includes a high-voltage electrode 19, a terminal post 20 and a catalyst gasket 21. The high-voltage electrode 19 is fixedly installed on a connecting plate 22 at the end. A plurality of high-voltage electrodes 19 are fixed on the connecting plate 22 in a honeycomb coal shape, and the arrangement positions of the plurality of high-voltage electrodes 19 correspond to the plurality of corundum tubes 16 one by one. The wires of the plurality of high-voltage electrodes 19 converge on the terminal post 20. The terminal post 20 is fixed above the connecting plate 22 and is connected with the high-voltage power supply 1 through the wiring port 9. The catalyst gasket 21 is used for placing catalysts and is located at the lower end of the high-voltage electrode 19.

[0037] A biomass tar staged plasma catalytic reforming method based on the above device includes the following steps.

[0038] Step 1: Turn on the staged heating furnace 2 and set the temperature of the staged heating furnace. According to the characteristics of the treated gas, the temperatures of the upper heating furnace 201 and the lower heating furnace 202 are set on the temperature control system 4 respectively.

[0039] Step two: open the high voltage power supply 1, according to the actual conditions, set the appropriate parameters, ensure the formation of stable, reliable discharge plasma;

[0040] Step three: the biomass gasification synthesis gas is input into the gas inlet 11 of the reactor 3, the gas input is adjusted to make the gas flow uniformly and stably through the plasma catalytic zone 301 and the thermal catalytic zone 302;

[0041] Step four: the treated biomass gasification synthesis gas is discharged from the gas outlet 10 of the reactor 3 and collected for subsequent use;

[0042] Step five: after the gas treatment is completed, the input of the biomass gasification synthesis gas is stopped, the heating furnace 2 and the high voltage power supply 1 are closed, the gas collection is stopped, and the system operation is ended.

[0043] Through the above system and method, the efficient and stable conversion of biomass gasification tar is realized, the contradiction between plasma and temperature is avoided, and the quality of the biomass gasification synthesis gas is improved.

Claims

1. A biomass tar fractionating plasma catalytic system, comprising a high-voltage power supply (1), a heating furnace (2), a reactor (3), and a temperature control system (4); characterized in that, The heating furnace (2) is divided into upper heating furnace (201) and lower heating furnace (202), the reactor (3) is divided into ion catalytic zone (301) and thermal catalytic zone (302) from top to bottom, the upper heating furnace (201) is wrapped outside the ion catalytic zone (301), the lower heating furnace (202) is wrapped outside the thermal catalytic zone (302), and the temperature control system is connected with the upper heating furnace (201) and the lower heating furnace (202) respectively, and the high-voltage power supply (1) is connected with the ion catalytic zone (301); The reactor (3) is provided with a boss (12) for dividing the reactor (3) into the ion catalytic zone (301) and the thermal catalytic zone (302), the corundum pipe unit (5) is installed above the boss (12), and the high-voltage electrode unit (13) is arranged in the corundum pipe unit (5); The thermal catalytic zone (302) is provided with a baffle (6) for placing catalyst.

2. The biomass tar fractionating plasma catalytic system according to claim 1, wherein, The upper and lower ends of the reactor (3) are respectively provided with an upper cover (7) and a lower cover (8), the upper cover (7) is provided with a wiring port (9), and the lower cover (8) is provided with an air outlet (10); The upper end side of the reactor (3) is provided with an air inlet (11).

3. The biomass tar fractionating plasma catalytic system according to claim 2, wherein, The corundum pipe unit (5) comprises a plurality of corundum pipes (16), a low-voltage electrode (17) and a support plate (18), the corundum pipes (16) are fixedly installed on the support plate (18), the support plate (18) is placed on the boss (12), and the low-voltage electrode (17) is wrapped on the corundum pipe (16); The upper side of the reactor (3) is provided with a wire outlet (15), and the low-voltage electrode (17) is grounded through the wire outlet (15); The corundum pipes (16) are distributed on the support plate (18) in a honeycomb coal shape, and the high-voltage electrode unit (13) comprises a plurality of high-voltage electrodes (19) corresponding to the corundum pipes (16) one by one.

4. The biomass tar fractionating plasma catalytic system according to claim 3, wherein, The high-voltage electrode unit (13) comprises a plurality of high-voltage electrodes (19) and catalyst gaskets (21), the upper end of the high-voltage electrode (19) is fixedly installed with a connecting plate (22), the installation position of the high-voltage electrode (19) corresponds to the corundum pipe (16) one by one, and the high-voltage electrode (19) is connected with the high-voltage power supply (1); The catalyst gasket (21) is fixedly installed at the lower end of the high-voltage electrode (19).

5. The biomass tar fractionating plasma catalytic system according to claim 1, wherein, The reactor (3) is a quartz tube.

6. The biomass tar fractionating plasma catalytic system according to claim 4, wherein, The connecting plate (22) is provided with a wiring column (20) for converging the wires of the high-voltage electrodes (19), and the wiring column (20) is connected with the high-voltage power supply (1) through the wiring port (9).

7. The biomass tar fractionating plasma catalytic system according to claim 3, wherein, The low-voltage electrode (17) is a metal mesh.

8. The biomass tar fractionating plasma catalytic system according to claim 3, wherein, The upper end of the corundum pipe (16) is provided with a sealing plate (14).

9. A method of using the biomass tar fractionating plasma catalytic system according to any one of claims 1-8, characterized in that, The method comprises the following steps: (1) turn on the heating furnace, set the temperature of the upper and lower heating furnaces according to the characteristics of the treated gas; (2) turn on the high-voltage power supply, set the current parameters, and form a stable and reliable discharge plasma; (3) introduce biomass gasification synthesis gas into the air inlet, adjust the air inlet amount, so that the gas flow is uniform and stable through the discharge area and the catalyst area; (4) collect the treated biomass gasification synthesis gas from the air outlet; (5) After the gas treatment is completed, the biomass gasification synthesis gas is stopped, the heating furnace, the high-voltage power supply is closed, and the collection gas is stopped, and the system operation is ended.

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