Tar catalytic cracking device based on joule heat reactor and product processing method

Abstract

The present application belongs to the technical field of biomass pyrolysis product processing, and provides a biomass tar catalytic cracking device and product processing method, wherein the cracking device is heated by Joule heat, and comprises a biomass pyrolysis system, a tar catalytic cracking system, a bio-oil condensation system and a hydrogen-rich combustible gas collection system. The tar catalytic cracking system comprises a Joule heat cracking reactor and a photovoltaic power generation device, and the Joule heat cracking reactor comprises a cylindrical electric heating sheet, a circular aperture plate and a cracking reaction bin. The inner and outer surfaces of the cylindrical electric heating sheet are coated with a catalyst, and the cylindrical electric heating sheet is used as a heat source to directly heat the catalyst and reactants, thereby completing the adsorption and pyrolysis of the tar in one step and achieving high processing efficiency. Meanwhile, the present application collects three products, i.e. biochar, bio-oil and hydrogen-rich combustible gas, through multi-stage processing, which is helpful to realize the high-value utilization of biomass.

Description

Technical Field

[0001] This invention belongs to the field of biomass pyrolysis product processing technology, specifically relating to a tar catalytic cracking device and product processing method. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Biomass pyrolysis refers to the process of heating biomass under anaerobic or oxygen-deficient conditions, causing the organic components to decompose at high temperatures, thereby releasing small-molecule volatiles from the solid. Pyrolysis gas is rich in combustible gases such as H2, CO, and CH4, and can be used to produce chemical products such as syngas and methanol. Upgraded pyrolysis gas can also be used as fuel for gas turbines, internal combustion engines, and fuel cells. However, in addition to combustible gas components, biomass pyrolysis gas also contains impurities such as tar, particulate matter, and acidic gases. Tar has the highest concentration in pyrolysis gas and is most likely to cause blockage and corrosion in equipment such as gas turbines and internal combustion engines. To improve the adaptability of pyrolysis gas in different equipment, it is necessary to further reduce the tar content and improve the quality of the pyrolysis gas.

[0004] To address the problem of pyrolysis tar removal, catalytic cracking technology can convert tar into hydrogen-rich combustible gas, enabling energy recovery and utilization. However, in practical applications, the ambient temperature for tar catalytic cracking is as high as 800℃ and above. Traditional heating methods use external heat sources for indirect heating, resulting in high reactor energy consumption, low energy conversion efficiency, and poor flexibility, which limits the development and application of tar catalytic cracking technology. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a tar catalytic cracking device and product processing method based on a Joule thermal reactor, aiming to solve the issues of high energy consumption, low efficiency, and poor flexibility in existing tar catalytic cracking devices. This invention incorporates cylindrical heating elements within the Joule thermal cracking reactor. The inner and outer surfaces of these heating elements are coated with a catalyst. The cylindrical heating elements act as a heat source, directly heating the catalyst and reactants, completing the adsorption and pyrolysis of tar in one step with high processing efficiency. Simultaneously, this invention collects three products—biochar, bio-oil, and hydrogen-rich combustible gas—through multi-stage processing, contributing to the high-value utilization of biomass.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a tar catalytic cracking device based on a Joule thermal reactor, comprising: a biomass pyrolysis system, a tar catalytic cracking system, a bio-oil condensation section, and a hydrogen-rich combustible gas collection system;

[0008] The tar catalytic cracking system includes a Joule thermal cracking reactor and a photovoltaic power generation device. The inlet of the Joule thermal cracking reactor is connected to the pyrolysis gas outlet of the biomass pyrolysis system, and the Joule thermal cracking reactor is also connected to the photovoltaic power generation device.

[0009] The bio-oil condensation section includes a primary condenser, a secondary condenser, and an oil storage tank. The inlet of the primary condenser is connected to the outlet of the Joule thermal cracking reactor, the outlet of the primary condenser is connected to the inlet of the secondary condenser, and the outlet of the secondary condenser is connected to a hydrogen-rich combustible gas collection section.

[0010] In some embodiments, the Joule pyrolysis reactor includes: cylindrical heating elements, a circular perforated plate, and a pyrolysis reaction chamber. The pyrolysis reaction chamber contains the circular perforated plate, on which multiple cylindrical heating elements are uniformly arranged in a ring. The inner and outer surfaces of the cylindrical heating elements are coated with a catalyst. The cylindrical heating elements are connected in series and electrically connected to a photovoltaic power generation device. When current passes through the Joule pyrolysis reactor, the conductive material generates high temperatures on its surface due to resistance, and the catalyst coating on the conductive material surface allows for direct catalytic cracking of volatile components such as tar. The photovoltaic power generation device uses solar photovoltaic panels to supply power and is connected to the Joule pyrolysis reactor to provide the electrical energy required for the catalytic cracking of tar.

[0011] In some embodiments, the catalyst is selected from inorganic salt catalysts, supported metal catalysts, or molecular sieve catalysts;

[0012] Preferably, the salt in the inorganic salt catalyst is a sodium salt or a potassium salt;

[0013] Preferably, the metal of the supported metal catalyst is nickel or iron;

[0014] Preferably, the molecular sieve catalyst is of type ZSM-5, β-type, or Y-type.

[0015] In some embodiments, the pyrolysis reaction chamber is divided into a reaction zone and a storage zone. The space below the circular perforated plate is the reaction zone, and the space above the circular perforated plate is the storage zone. Connecting wires are installed on the circular perforated plate, connecting cylindrical heating elements in series. The two ends of the wires are connected to a photovoltaic power generation device. Vent holes are distributed at the connection between the circular perforated plate and the cylindrical heating elements to discharge the pyrolysis gas after pyrolysis from the heating elements. The pyrolysis reaction chamber includes a reaction zone and a storage zone. The pyrolysis gas containing volatile components such as tar undergoes catalytic pyrolysis in the reaction zone below the circular perforated plate, and the pyrolysis gas after complete reaction enters the upper storage zone through the vent holes on the circular perforated plate.

[0016] In some embodiments, the biomass pyrolysis unit includes a feeding device, a pyrolyzer, and a char storage tank, which are connected in sequence. The feeding device is connected to the inlet of the pyrolyzer to feed the crushed biomass into the pyrolyzer for pyrolysis. The outlet of the pyrolyzer is connected to the char storage tank and a pyrolysis gas pipeline. The solid product biochar after pyrolysis is stored in the char storage tank, and the pyrolysis gas containing volatiles such as tar is discharged from the pyrolyzer along the rising pipeline.

[0017] In some embodiments, circulating cooling water from the secondary condenser is introduced outside the condenser tubes of the primary condenser to condense the heavy components and a small amount of light components remaining after pyrolysis of the bio-oil; the outlet of the secondary condenser is connected to a hydrogen-rich combustible gas collection unit, and circulating cooling water is introduced outside the condenser tubes to condense most of the light components of the bio-oil; the oil storage tank is connected to the primary and secondary condensers for the collection and storage of bio-oil for later processing and utilization.

[0018] In some embodiments, the hydrogen-rich combustible gas collection unit includes a compressor and a gas storage tank. The inlet of the compressor is connected to the outlet of the secondary condenser, and the outlet of the compressor is connected to the inlet of the gas storage tank. The compressor is used to pressurize the hydrogen-rich combustible gas at the outlet of the bio-oil condenser; the inlet of the gas storage tank is connected to the compressor for collecting the hydrogen-rich combustible gas.

[0019] In some embodiments, the Joule pyrolysis reactor is equipped with inlet valve A, outlet valve B, and outlet valve C at its inlet and outlet, and an inlet valve D is installed inside the pyrolysis gas pipeline. The opening and closing of the valves are controlled by a controller. When the pyrolysis equipment is operating normally, inlet valve A is closed, D is open, outlet valve B is open, and C is closed. After the pyrolysis equipment has been running continuously for a certain period, carbon deposits may accumulate on the surface of the heating elements, affecting operation. In this case, the controller opens inlet valve A to allow air to enter, closes inlet valve D, closes outlet valve B, and opens outlet valve C. Because the heating elements heat up rapidly, the carbon deposits on their surface are oxidized the instant air is introduced. After the carbon deposits are removed, the equipment can continue to be used.

[0020] A second aspect of the present invention provides a method for treating catalytic cracking products of biomass pyrolysis tar, comprising:

[0021] After the biomass is crushed, it is pyrolyzed under anaerobic conditions to produce biochar and pyrolysis gas containing tar.

[0022] The pyrolysis gas containing tar is brought into contact with a catalyst in a Joule thermal reactor to carry out a catalytic cracking reaction, generating combustible gas rich in H2, small molecule organic matter and a small amount of carbon deposits. At the same time, a photovoltaic power generation device is used to provide energy for the Joule thermal reactor.

[0023] The H2-rich combustible gas is pressurized and then stored.

[0024] A third aspect of the present invention provides the application of the above-described apparatus in biomass utilization.

[0025] Beneficial effects of the present invention

[0026] (1) The catalytic cracking device of the present invention adopts a Joule thermal reactor. When current passes through, the cylindrical heating element is directly heated due to its own resistance. This heating method eliminates the convection and radiation heat transfer processes in the traditional heating method, and can reduce the system ambient temperature from 800°C and above in the traditional heating method to 50-400°C, while maintaining the catalyst surface temperature at 800-2000°C, which greatly improves the energy conversion efficiency and reduces energy consumption.

[0027] (2) In this invention, the surface of the cylindrical heating element can be loaded with a catalyst. Since the tar cracking reaction takes place on the surface of the catalyst, the heating element directly heats the catalyst and reactants as a heat source, completing the adsorption and pyrolysis of tar in one step, realizing the integration of the catalyst and the heat source, improving the speed of the catalytic reaction, and saving reaction time.

[0028] (3) The heating and cooling rates of the surface of the electric heating element in this invention are as high as 1000℃ / s, which is much greater than the temperature change rate (0~100℃ / min) of the traditional heating method. This greatly reduces the start-up and shutdown time of the pyrolysis device. On the one hand, it reduces the energy consumption for catalytic pyrolysis preparation, and on the other hand, it enables real-time control of the device start-up and shutdown, which helps to eliminate carbon deposits in a timely manner.

[0029] (4) The device of the present invention adopts a distributed arrangement, such as the electric heating element using photovoltaic panels for power supply, and the electrical energy converted from solar energy provides heat for catalytic cracking reaction, which can realize flexible and efficient use of energy.

[0030] (5) The device of the present invention, by setting up a biomass pyrolysis section, a tar catalytic cracking section, a bio-oil condensation section and a hydrogen-rich combustible gas collection section, collects three products, biochar, bio-oil and hydrogen-rich combustible gas through multi-stage processing, which helps to realize the high-value utilization of biomass.

[0031] (6) The device of the present invention has a simple structure, is easy to operate, is highly practical, and is easy to promote. Attached Figure Description

[0032] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. Exemplary embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0033] Figure 1 This is a schematic diagram of the structure of a pyrolysis tar catalytic cracking device and product processing system based on a Joule thermal reactor according to one or more embodiments of the present invention.

[0034] Figure 2This is a schematic diagram of the structure of a pyrolysis tar catalytic cracking device based on a Joule thermal reactor according to one or more embodiments of the present invention.

[0035] Figure 3 This is a top view of a circular perforated plate inside a catalytic cracking reactor according to one or more embodiments of the present invention.

[0036] Note: The distances or dimensions between parts have been exaggerated to show their positions; the diagram is for illustrative purposes only.

[0037] Among them, 1-hopper; 2-crusher; 3-feeder; 4-pyrolyzer; 5-carbon storage tank; 6-cylindrical electric heating element; 7-inlet valve A; 8-oil storage tank; 9-gas storage tank; 10-compressor; 11-secondary condenser; 12-primary condenser; 13-joule pyrolysis reactor; 14-outlet valve B; 15-photovoltaic panel; 16-outlet valve C; 17-inlet valve D; 18-controller; 19-catalyst; 20-outlet port; 21-circular orifice plate; 22-pyrolysis reaction chamber; 23-outer cylinder; 24-inner cylinder; 25-connecting wire. Detailed Implementation

[0038] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0039] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0040] like Figure 1 As shown, the present invention provides a biomass pyrolysis tar catalytic cracking device, comprising a biomass pyrolysis section, a tar catalytic cracking section, a bio-oil condensation section, and a hydrogen-rich combustible gas collection section, wherein...

[0041] The biomass pyrolysis unit includes a silo 1, a crusher 2, a feeder 3, a pyrolyzer 4, and a char storage tank 5. The silo 1, crusher 2, and feeder 3 are connected in sequence for feeding, conveying, and crushing biomass. The outlet of the feeder 3 is connected to the inlet of the pyrolyzer 4 to feed the crushed biomass into the pyrolyzer 4 for pyrolysis. The outlet of the pyrolyzer 4 is connected to the char storage tank 5 and the pyrolysis gas pipeline. The solid product biochar after pyrolysis enters the char storage tank 5 for storage, and the pyrolysis gas containing volatiles such as tar is discharged from the pyrolyzer 4 along the rising pipeline.

[0042] The tar catalytic cracking section includes a Joule thermal cracking reactor 13 and a photovoltaic panel 15. The inlet of the Joule thermal cracking reactor 13 is connected to the pyrolysis gas pipeline, and the outlet is connected to the bio-oil condensation section. When current passes through the reactor, the conductive material generates high temperature on its surface due to the existence of resistance, and the conductive material surface is coated with catalyst 19, which can be directly used for the catalytic cracking of volatiles such as tar. The photovoltaic panel 15 is connected to the Joule thermal cracking reactor 13 and is used to provide the electrical energy required for the catalytic cracking of tar.

[0043] The bio-oil condensation section includes a primary condenser 12, a secondary condenser 11, and an oil storage tank 8. The inlet of the primary condenser 12 is connected to the Joule thermal cracking reactor 13, and the outlet is connected to the secondary condenser 11. Circulating cooling water from the secondary condenser 11 is introduced outside the condenser tubes to condense the heavy components and a small amount of light components remaining after cracking of the bio-oil. The outlet of the secondary condenser 11 is connected to a hydrogen-rich combustible gas collection section, and circulating cooling water is introduced outside the condenser tubes to condense most of the light components of the bio-oil. The oil storage tank 8 is connected to the primary and secondary condensers 11 and 12 and is used for the collection and storage of bio-oil for later processing.

[0044] The hydrogen-rich combustible gas collection unit includes a compressor 10 and a gas storage tank 9. The compressor 10 is used to pressurize the hydrogen-rich combustible gas at the outlet of the bio-oil condenser. The inlet of the gas storage tank 9 is connected to the compressor 10 and is used to collect the hydrogen-rich combustible gas.

[0045] As a further preferred option, such as Figure 2 , Figure 3 As shown, the Joule pyrolysis reactor 13 includes cylindrical heating elements 6, a circular perforated plate 21, and a pyrolysis reaction chamber 22. The upper part of the cylindrical heating elements 6 is connected to the circular perforated plate 21, and they are evenly arranged in a ring on the plate. The inner cylinder 24 and outer cylinder 23 of the cylindrical heating elements 6 are connected in a U-shape at the bottom, and their surfaces are coated with catalyst for catalytically cracking the tar adsorbed on the surface of the heating elements. Connecting wires 25 are installed on the circular perforated plate 21, allowing the cylindrical heating elements 6 to be connected in series. The inner cylinder 24 of each preceding heating element is connected to the outer cylinder 23, and both ends of the connecting wires 25 are connected to the photovoltaic panel 15. Vent holes 20 are distributed at the connection between the circular perforated plate 21 and the cylindrical heating elements 6 to discharge the pyrolysis gas after cracking. Both the inner and outer cylinders of the cylindrical heating elements 6 are hollow cylinders, but at the bottom, they are smoothly connected, achieving series connection between the inner and outer cylinders. The pyrolysis reaction chamber 22 includes a reaction zone and a storage zone. The pyrolysis gas containing volatiles such as tar is catalytically pyrolyzed in the reaction zone below the circular perforated plate 21. After the reaction is complete, the pyrolysis gas enters the upper storage zone through the gas outlet 20 on the circular perforated plate 21.

[0046] As a further preferred option, such as Figure 1The Joule pyrolysis reactor 13 is equipped with an inlet valve A7, an outlet valve B14, and an outlet valve C16 at its inlet and outlet. An inlet valve D17 is installed inside the pyrolysis gas pipeline. The opening and closing of these valves are controlled by a controller 18. During normal operation of the pyrolysis equipment, the controller 18 closes inlet valve A7, opens D17, opens outlet valve B14, and closes C16. After continuous operation for a certain period, carbon deposits accumulate on the surface of the heating elements, affecting operation. In this case, the controller 18 opens inlet valve A7 to allow air to pass through, closes inlet valve D17, closes outlet valve B14, and opens C16. Because the heating elements heat up rapidly, the carbon deposits on their surface are oxidized instantly upon the introduction of air. After the carbon deposits are removed, the equipment can continue to be used.

[0047] In some embodiments, the method for treating biomass pyrolysis tar catalytic cracking products of the present invention includes the following steps:

[0048] After the biomass in the silo 1 is crushed in the crusher 2, it enters the pyrolyzer 4 through the feeder 3 and is pyrolyzed under oxygen-deficient conditions to produce biochar and pyrolysis gas. Driven by the screw, the pyrolysis products move to the end of the pyrolyzer 4. The biochar enters the storage tank 5 for storage, and the pyrolysis gas is discharged from the upper pipe.

[0049] The pyrolysis gas containing volatiles such as tar enters the reaction zone of the pyrolysis reaction chamber 22. During the gas rise, the volatiles such as tar are adsorbed onto the cylindrical electric heating element 6 and come into contact with the catalyst 19 on its surface at high temperature, resulting in a catalytic pyrolysis reaction that generates combustible gas rich in H2, small molecule organic matter, and a small amount of carbon deposits. At the same time, the photovoltaic panel 15 converts solar energy into electrical energy to provide energy for the cylindrical electric heating element 6.

[0050] The pyrolysis gas after cracking is discharged through the vent 20 on the circular perforated plate 21 and enters the storage area of ​​the cracking reaction chamber 22.

[0051] The gas in the storage area enters the primary condenser 12 and the secondary condenser 11 in sequence, where the heavy and light components of the bio-oil are condensed and then stored in the oil storage tank 8.

[0052] The remaining hydrogen-rich combustible gas after condensation is pressurized by compressor 10 and then stored in gas storage tank 9.

[0053] Furthermore, the working temperature of the inner cylindrical electric heating element 6 of the Joule thermal cracking reactor 13 exceeds 1000℃, and the surface of the electric heating element can be coated with catalyst 19 to achieve the integration of catalyst and heat source, thereby improving the catalytic efficiency of tar. Since the electric heating element directly generates Joule heat through electricity, the heating rate of the electric heating element surface can reach 1000℃ / s, which is much greater than that of traditional fixed bed reactors (about 0 to 100℃ / min), greatly reducing the preparation time of cracking reaction and increasing the controllability of reaction start and stop.

[0054] Furthermore, after the device has been running for a certain period of time, carbon deposits easily accumulate on the conductive materials and catalyst surfaces, reducing the catalytic efficiency of tar cracking. This device is equipped with a controller 18 to control the opening and closing of each valve, allowing air to be introduced after a certain operating time to remove the carbon deposits. Because the Joule thermal reactor has a heating rate as high as 1000℃ / s, the carbon deposits on the conductive materials and catalyst surfaces can be removed instantly. Therefore, the device easily enables the recycling of conductive materials and catalysts, reducing the impact of carbon deposits on tar cracking efficiency.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A tar catalytic cracking device based on a Joule thermal cracking reactor, characterized in that, include: Biomass pyrolysis system, tar catalytic cracking system, bio-oil condensation section and hydrogen-rich combustible gas collection system; The tar catalytic cracking system includes a Joule thermal cracking reactor and a photovoltaic power generation device. The inlet of the Joule thermal cracking reactor is connected to the pyrolysis gas outlet of the biomass pyrolysis system, and the Joule thermal cracking reactor is also connected to the photovoltaic power generation device. The Joule pyrolysis reactor includes: cylindrical heating elements, a circular perforated plate, and a pyrolysis reaction chamber. The pyrolysis reaction chamber is equipped with a circular perforated plate, on which multiple cylindrical heating elements are evenly arranged in a ring. The inner and outer surfaces of the cylindrical heating elements are coated with a catalyst. The cylindrical heating elements are electrically connected in series and electrically connected to a photovoltaic power generation device. The inner and outer cylinders of the cylindrical heating elements are connected in a U-shape at the bottom. The pyrolysis reaction chamber is divided into a reaction zone and a storage zone. The space below the circular perforated plate is the reaction zone, and the space above the circular perforated plate is the storage zone. The bio-oil condensation section includes a primary condenser, a secondary condenser, and an oil storage tank. The inlet of the primary condenser is connected to the outlet of the Joule thermal cracking reactor, the outlet of the primary condenser is connected to the inlet of the secondary condenser, and the outlet of the secondary condenser is connected to a hydrogen-rich combustible gas collection system.

2. The tar catalytic cracking device based on a Joule thermal cracking reactor as described in claim 1, characterized in that, The catalyst is selected from inorganic salt catalysts, supported metal catalysts, or molecular sieve catalysts; The inorganic salt catalyst is a sodium salt or a potassium salt; The metal of the supported metal catalyst is nickel or iron; The molecular sieve catalyst is of type ZSM-5, β-type, or Y-type.

3. The tar catalytic cracking device based on a Joule thermal cracking reactor as described in claim 1, characterized in that, The biomass pyrolysis system includes a feeding device, a pyrolyzer, and a char storage tank, which are connected in sequence.

4. The tar catalytic cracking device based on a Joule thermal cracking reactor as described in claim 1, characterized in that, The circulating cooling water from the secondary condenser is introduced into the condenser tubes of the primary condenser.

5. The tar catalytic cracking device based on a Joule thermal cracking reactor as described in claim 1, characterized in that, The hydrogen-rich combustible gas collection system includes a compressor and a gas storage tank. The inlet of the compressor is connected to the outlet of the secondary condenser, and the outlet of the compressor is connected to the inlet of the gas storage tank.

6. The tar catalytic cracking device based on a Joule thermal cracking reactor as described in claim 1, characterized in that, The Joule pyrolysis reactor is equipped with an inlet valve A, an outlet valve B, and an outlet valve C at its inlet and outlet, and an inlet valve D is installed inside the pyrolysis gas pipeline.

7. A method for treating catalytic cracking products of biomass pyrolysis tar, characterized in that, The tar catalytic cracking device based on a Joule thermal cracking reactor as described in any one of claims 1-6 comprises: After the biomass is crushed, it is pyrolyzed under anaerobic conditions to produce biochar and pyrolysis gas containing tar. The pyrolysis gas containing tar is brought into contact with a catalyst in a Joule pyrolysis reactor to carry out a catalytic pyrolysis reaction, generating combustible gas rich in H2, small molecule organic matter and a small amount of carbon deposits. At the same time, a photovoltaic power generation device is used to provide energy for the Joule pyrolysis reactor. The H2-rich combustible gas is pressurized and then stored.

8. The application of the device according to any one of claims 1-6 in biomass utilization.

Images