INTEGRATED APPARATUS AND METHOD FOR COPRODUCTION OF CARBON AND HYDROGEN BY BIOMASS CASCADE PYROLYSIS-MICROWAVE GASIFICATION

Description

CROSS REFERENCE TO THE RELATED APPLICATIONS

This application is a continuation application of International Application No. PCT/CN2024/124175, filed on Oct. 11, 2024, which is based upon and claims priority to Chinese Patent Application No. 202311343870.4, filed on Oct. 17, 2023, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to the technical field of co-production of carbon and hydrogen by biomass pyrolysis gasification and in particular to an integrated apparatus and method for co-production of carbon and hydrogen by biomass cascade pyrolysis-microwave gasification.

BACKGROUND

The biomass resources include crop straws, animal husbandry excrements and forestry processing wastes and so on, which are recognized as the fourth largest energy source in the world. The appropriate utilization of the biomass can promote low-carbon agricultural development, relieve environmental problems, drive the industrial upgrade and increase the income of the farmers. The biomass gasification is a process in which the feedstock reacts with a given amount of oxygen, steam or CO₂ or the like to generate CO and H₂ (collectively called syngas) as well as a small amount of bio-oil and bio-char. But there are still many problems in the practical applications of the biomass gasification, which mainly include the following points: low hydrogen yield, poor gasification gas quality, low production, high tar yield, slow gasification rate and high energy consumption and the like. Microwave heating has the advantages of instantaneity, selectivity and penetrativity and the like and the microwave can be used in the gasification reactions to increase the hydrogen yield and processing efficiency.

In recent years, some research has been conducted on microwave-pyrolysis gasification technology at home and abroad. But, the microwave gasification has many defects. The US201611065781.8 discloses a biomass microwave-pyrolysis directed gasification method, in which a strong absorbing catalyst synthesized by multiple components are introduced for microwave pyrolysis and microwave gasification. However, this method has a single byproduct, and the product quality and added value remain to be improved. The patent 201811618224.3 discloses a biomass microwave gasification utilization method and system. In this method, various stages of gas products are comprehensively utilized to generate hydrogen by oxygen carrier reduction reaction. But it is also required to add additives into the microwave reactor, and it is a challenge to separate the reaction-generated solid products from the additives. Therefore, it can produce various stages of solid residues and have the disadvantages of complicated process, high energy consumption and high costs. The US202110029378.4 discloses a method and system for co-production of hydrogen and biochar through biomass pyrolysis gasification. In this method, in addition to high consumption of high-quality electric energy in the previous stage, it is also required to maintain the reaction temperatures of the reforming 500-800° C. and the combustion reactor 850-1000° C., which almost consumes all solid char products. Although the problem of single product is solved to some extent, the apparatus is complicated and huge and features many unit reactors, large volume and relatively low entire economics. The existing bottleneck problems of the biomass microwave-pyrolysis gasification technology can be summarized as the following points: (1) the biomass feedstock has low energy density and poor molecular polarity and are poor thermal absorbers and poor microwave absorbers. In order to reach the microwave reaction conditions, it needs to consume a huge amount of high-quality electric energy. If additives are added to improve the absorbing capability of the feedstock, solid products are difficult to separate out, leading to production of solid residues. (2) single process product and low added value; (3) huge apparatus, many devices, low efficiency, ease of pollution of the microwave feed port usually requiring to go through shutdown maintenance; due to these problems, under the conditions of complex process flow and high energy consumption, the entire technical economics of the biomass microwave-pyrolysis gasification technology is bad, leading to difficulty in large-scale application and promotion. Therefore, it is necessary to develop a low-cost, efficient and compact integrated apparatus technology for co-production of high-value added carbon and hydrogen products from biomass.

SUMMARY

The object of the present disclosure aims to solve the defects of the prior arts by providing an integrated apparatus and method for co-production of carbon and hydrogen by biomass cascade pyrolysis-microwave gasification. This apparatus features compact structure, high efficiency, energy cascade utilization, high product quality and yield, and long-time continuous operation. Therefore, the problems of huge apparatus, high costs, single product and poor economics in the prior arts can be solved.

In order to solve the above technical problems, the present disclosure provides the following technical scheme.

An integrated apparatus for co-production of carbon and hydrogen by biomass cascade pyrolysis-microwave gasification, including an integrated reaction system, an internal and external radial energy supply system, and a product separation and collection system;

the integrated reaction system includes a drying chamber, a low-temperature pyrolysis chamber, a microwave gasification chamber, and an online reforming reaction chamber, wherein the drying chamber, the low-temperature pyrolysis chamber, and the microwave gasification chamber are sequentially communicated from top down, the online reforming reaction chamber is disposed outside the low-temperature pyrolysis chamber; the drying chamber is configured to load and dry a biomass feedstock; the low-temperature pyrolysis chamber is configured to perform preliminary pyrolysis carbonization on the biomass feedstock to improve an absorbing capability of the biomass feedstock; the microwave gasification chamber is connected with the online reforming reaction chamber via a gas phase outlet to produce a high-quality gas product and a porous carbon product with a high-absorbing material; and the online reforming reaction chamber is connected with the product separation and collection system via a reformed gas outlet to perform online catalytic reforming on the high-quality gas product generated by microwave gasification;

the internal and external radial energy supply system includes a combustion heat supply chamber, a gasification agent chamber, and a hoop direct-feed microwave generator, wherein the combustion heat supply chamber and the gasification agent chamber are disposed from top down along a central axis of an interior of the integrated reaction system, the hoop direct-feed microwave generator is disposed outside the microwave gasification chamber; the combustion heat supply chamber penetrates through interiors of the drying chamber and the low-temperature pyrolysis chamber, with above-disposed drying tail gas outlets located between the drying chamber and the low-temperature pyrolysis chamber to, with a combustion tail gas of a pyrolysis gas, supply heat for a pyrolysis reaction and material drying, and with below-disposed pyrolysis gas outlets connected with the low-temperature pyrolysis chamber; a blower is connected with the combustion heat supply chamber via a combustion air supply tube; the gasification agent chamber is disposed on an axis of the microwave gasification chamber for a gasification reaction of a material, an upper top of the gasification agent chamber is connected with the microwave gasification chamber via first gasification agent outlets, and a bottom of the gasification agent chamber is connected with a gasification agent inlet; the hoop direct-feed microwave generator is configured to provide a microwave for the microwave gasification chamber;

the product separation and collection system includes a first-level gas separation device, a second-level purification device, a gas storage cylinder, and a carbon material collection box; the first-level gas separation device is configured to receive and separate a reformed gas and provide a gasification agent for the gasification reaction, wherein a reformed gas inlet, a crude hydrogen outlet, and a second gasification agent outlet are disposed on the first-level gas separation device, the reformed gas inlet is connected with the reformed gas outlet, the crude hydrogen outlet is connected with the gas storage cylinder via the second-level purification device, and the second gasification agent outlet is connected with the gasification agent inlet; the carbon material collection box is connected with a solid outlet at a bottom of the microwave gasification chamber.

Furthermore, the drying chamber is an inverted-funnel shape with upper large and lower small, wherein a ratio of inner diameters of an upper end and a lower end of the drying chamber is 2:1 to 3:1 and an inclination angle α of an inner wall of the drying chamber is 30°-60°; an upper end of the combustion heat supply chamber is a conical frustum structure, the drying tail gas outlets are disposed on the conical frustum structure, a ratio of a bottom diameter of the conical frustum structure to an inner diameter of the low-temperature pyrolysis chamber is 1:2 to 2:3, a ratio of a top diameter of the conical frustum structure to the bottom diameter is 1:2 to 1:3, a ratio of the top diameter of the conical frustum structure to a height of the conical frustum structure is 1:1 to 1:1.5, and a ratio of the top diameter of the conical frustum structure to an inner diameter of the combustion heat supply chamber is 1:1; a ratio of a height of the microwave gasification chamber to a height of the low-temperature pyrolysis chamber is 2:3, and a ratio of a height of the online reforming reaction chamber to the height of the low-temperature pyrolysis chamber is 4:5 to 1:1.

Furthermore, a first-level microwave suppression partition plate and a second-level microwave suppression partition plate are disposed sequentially from top down between the low-temperature pyrolysis chamber and the microwave gasification chamber; a first end of the first-level microwave suppression partition plate is connected to a bottom of an inner wall of the low-temperature pyrolysis chamber, and a second end of the first-level microwave suppression partition plate is tilted downward at an inclination angle β of 20° to 45°; a first end of the second-level microwave suppression partition plate is connected to an outer wall of the gasification agent chamber, and a second end of the second-level microwave suppression partition plate is tilted downward at an inclination angle γ of β+15° and has a vertical distance of 0 to 50 mm from an outer end of the first-level microwave suppression partition plate; a ratio of a spacing between an outer end of the second-level microwave suppression partition plate and an outer wall of the microwave gasification chamber to an inner diameter of the microwave gasification chamber is 3:4.

Furthermore, the pyrolysis gas outlets are symmetrically and circumferentially disposed in 4 to 6 layers each of which includes 2 to 4 pyrolysis gas outlets, along an inner wall of the combustion heat supply chamber; and the combustion air supply tube is provided with combustion spray nozzles, wherein the combustion spray nozzles have a diameter of 40 mm and are located between two layers of pyrolysis gas outlets.

Furthermore, the first gasification agent outlets are symmetrically and circumferentially disposed in 4 to 6 layers each of which includes 2 to 4 first gasification agent outlets, along an outer wall of the gasification agent chamber.

Furthermore, a peripheral symmetrical feed port is disposed on an outer wall of the microwave gasification chamber, the hoop direct-feed microwave generator is connected to the peripheral symmetrical feed port via an echo suppressor, a bottom air curtain outlet is disposed at a bottom of the peripheral symmetrical feed port, and the gasification agent chamber is connected with the bottom air curtain outlet.

A method for co-production of carbon and hydrogen by biomass cascade pyrolysis-microwave gasification by using the integrated apparatus for co-production of carbon and hydrogen by biomass cascade pyrolysis-microwave gasification according to claim 1, including the following steps:

• • at step S1, the biomass feedstock enters the drying chamber and is heated and dried by the drying tail gas outlets, and then enters the low-temperature pyrolysis chamber for the preliminary pyrolysis carbonization; the pyrolysis gas enters the combustion heat supply chamber via the pyrolysis gas outlets, and a remaining solid material enters the microwave gasification chamber;
  • at step S2, the remaining solid material goes through the gasification reaction with the gasification agent in the microwave gasification chamber; the high-quality gas product enters the online reforming reaction chamber via the gas phase outlet for the online catalytic reforming and then enters the first-level gas separation device; the porous carbon product enters the carbon material collection box through the solid outlet and is cooled down to below 60° C. in an air-isolated state.
  • at step S3, the pyrolysis gas in the step S1 is combusted in cooperation with an air in the combustion heat supply chamber to supply heat to the low-temperature pyrolysis chamber; the combustion tail gas is discharged into the drying chamber through the drying tail gas outlets for drying; the reformed gas in the step S2 is separated into crude hydrogen and the gasification agent through the first-level gas separation device; the gasification agent is returned to the microwave gasification chamber through the gasification agent chamber to fully contact with the material for the gasification reaction, and an air curtain is formed on a surface of a peripheral symmetrical feed port by a bottom air curtain outlet so as to protect the peripheral symmetrical feed port.

Furthermore, in the step S1, a pyrolysis reaction temperature of the low-temperature pyrolysis chamber is 200° C. to 360° C., wherein the pyrolysis reaction temperature is adjusted based on the material and heat supply conditions; in the step S2, a gasification reaction temperature of the microwave gasification chamber is 600° C. to 1200° C.; in the step S3, a combustion temperature in the combustion heat supply chamber is 900° C. to 1300° C., and an excess air coefficient is 1.2 to 1.5.

Furthermore, in the step S2, the gasification agent is separated carbon dioxide or a gas mixture of the separated carbon dioxide and a small amount of other gases, the gasification agent is introduced in a form of gaseous state, and a mass ratio of the gasification agent to the remaining solid material is 1:2 to 4:1.

Furthermore, the step S2, a natural catalyst and a synthetic supported catalyst for catalyzing tar to pyrolyse are placed in the online reforming reaction chamber, the synthetic supported catalyst includes a nickel-based synthetic supported catalyst with γ-Al₂O₃ as a carrier and nano nickel oxide as an active component, wherein the nickel-based synthetic supported catalyst is prepared by impregnation, drying, and calcination in air atmosphere at a temperature of 400° C., with nickel nitrate and the γ-Al₂O₃ as raw materials and urea as a precipitant.

The co-production of carbon and hydrogen by biomass cascade pyrolysis-microwave gasification is a complex process which involves multiple physic and chemical changes. Firstly, in the cascade pyrolysis stage, the biomass decomposes under a gradually increasing temperature. At a low temperature, the water in the biomass is evaporated and then macromolecular organic matters start breaking, producing some primary products, such as volatile components and cokes. Next, in the microwave gasification stage, the special microwave heating manner enables the interior of the biomass to be heated quickly. The microwave can promote high-speed vibration and friction of the molecules and speed up the chemical reactions. The organic matters in the biomass are further decomposed to generate more gas products, including hydrogen, carbon monoxide and the like. In the co-production of carbon and hydrogen, a series of complex reactions occur. The carbon element in the biomass is converted into carbon-containing compound or solid carbonaceous material under specific conditions. Furthermore, the hydrogen element is released in the form of gas and also can participate in other chemical reactions to form hydrocarbon compounds. This process is affected by multiple factors, for example, biomass species and composition, biomass pyrolysis and gasification temperatures, microwave power and frequency, and reaction time and the like. Different conditions can lead to different product distributions and compositions.

Compared with the prior arts, the present disclosure has the following beneficial effects.

(1) In the present disclosure, the biomass feedstock first goes through fast low-temperature pyrolysis in the low-temperature pyrolysis chamber. With the fast heating rate realized by the large temperature difference between the low reaction temperature and the heat source, the oxygen-containing functional groups in the biomass can be effectively removed so as to improve the gasification gas quality.

(2) In the present disclosure, the biomass completes preliminary fast pyrolysis carbonization in the low-temperature pyrolysis chamber, with its dielectric property significantly improved; and it has better absorbing capability in the microwave cascade gasification system.

(3) In the present disclosure, the low-temperature pyrolysis chamber is heated by the low-quality heat source f pyrolysis gas combustion heat to complete high-energy-consumption biomass drying and preliminary pyrolysis, reducing the input of the high-quality electric energy in the microwave gasification process.

(4) In the present disclosure, the microwave cascade gasification system uses the advantages of the uniform and fast heating and entire heat generation of microwave in cooperation with low-temperature pyrolysis to improve the feedstock absorbing property while using the symmetric feed design to significantly shorten the gasification time. Further, the microwave energy has high density and more easily reaches a reaction energy barrier to promote gas generation and hydrogen production. Moreover, the feed port is effectively protected by air curtain design to improve the operational reliability of the equipment, avoiding frequent shutdown cleaning maintenance.

(5) By collaboration of multiple functions, the present disclosure provides a compact, integrated, continuous and efficient reaction apparatus to realize multiple functions in one reactor, greatly reducing the equipment volume and land occupation area, lowering the equipment costs, increasing the process economics and facilitating technical promotion in large scope.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGURE is a structural schematic diagram illustrating an integrated apparatus for co-production of carbon and hydrogen by biomass cascade pyrolysis-microwave gasification according to an embodiment of the present disclosure.

The numerals of the drawings are described below:

• • 1. drying chamber, 2. low-temperature pyrolysis chamber, 2-1. pyrolysis gas outlet, 2-2. first-level microwave suppression partition plate, 2-3. second-level microwave suppression partition plate, 3. microwave gasification chamber, 3-1. gas phase outlet, 3-2. solid outlet, 4. online reforming reaction chamber, 5. combustion heat supply chamber, 5-1. combustion spray nozzle, 5-2. combustion air supply tube, 5-3. drying tail gas outlet, 5-4. blower, 5-5. conical frustum structure, 6. gasification agent chamber, 6-1. bottom gasification agent inlet, 6-2. gasification agent outlet, 6-3. bottom air curtain outlet, 7. hoop direct-feed microwave generator, 7-1. echo suppressor, 7-2. peripheral symmetrical feed port, 8. first-level gas separation device, 8-1. reformed gas inlet, 8-2. crude hydrogen outlet, 8-3. gasification agent outlet, 9. second-level purification device, 9-1. crude hydrogen inlet, 9-2. high-purity hydrogen outlet, 10. gas storage cylinder, 11. carbon material collection box.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In order to deepen the understanding for the present disclosure, the present disclosure will be further detailed below in combination with drawings. This embodiment is used only to interpret the present disclosure rather than limit the scope of protection of the present disclosure.

The FIGURE shows an embodiment of an integrated apparatus for co-production of carbon and hydrogen by biomass cascade pyrolysis-microwave gasification, which includes an integrated reaction system, an internal and external radial energy supply system, and a product separation and collection system, which operate collaboratively.

The integrated reaction system includes a drying chamber 1, a low-temperature pyrolysis chamber 2, a microwave gasification chamber 3 sequentially communicated from top down as well as an online reforming reaction chamber 4 disposed outside the low-temperature pyrolysis chamber 2. The drying chamber 1 is configured to dry biomass feedstock, the low-temperature pyrolysis chamber 2 is configured to perform preliminary pyrolysis carbonization on the biomass feedstock to improve its absorbing capability and send the material into the microwave gasification chamber 3, the microwave gasification chamber 3 is configured to produce high-quality gas product and porous carbon product with the material with high absorbing property, and the online reforming reaction chamber 4 is configured to perform online catalytic reforming on the gas product generated by the microwave gasification.

The internal and external radial energy supply system includes a combustion heat supply chamber 5 and a gasification agent chamber 6 disposed from top down along a central axis of the interior of the integrated reaction system, as well as a hoop direct-feed microwave generator 7 disposed outside the microwave gasification chamber 3. The combustion heat supply chamber 5 is configured to burn the pyrolysis gas generated by the pyrolysis to supply heat for pyrolysis reaction and material drying. The gasification agent chamber 6 is configured to provide a gasification agent and protect a microwave feed port, and the hoop direct-feed microwave generator 7 is used to provide microwave for the microwave gasification reaction.

The product separation and collection system includes a first-level gas separation device 8, a second-level purification device 9, a gas storage cylinder 10, and a carbon material collection box 11. The first-level gas separation device 8 is configured to receive and separate a reformed gas product and provide a gasification agent for the gasification reaction. The second-level purification device 9 is configured to purify hydrogen. The gas storage cylinder 10 is configured to store high-purity hydrogen, and the carbon material collection box 11 is configured to store a porous carbon material.

Specifically, the inverted-funnel-shaped drying chamber with the upper large and the lower small is directly communicated with the low-temperature pyrolysis chamber 2, where a ratio of inner diameters of the upper end and the lower end of the drying chamber 1 is 2:1 and an inclination angle α of an inner wall of the drying chamber is 45°. A lower part of the low-temperature pyrolysis chamber 2 is connected with the microwave gasification chamber 3 via a first-level microwave suppression partition plate 2-2 and a second-level microwave suppression partition plate 2-3. One end of the first-level microwave suppression partition plate 2-2 is connected to the bottom of the inner wall of the low-temperature pyrolysis chamber 2 and the other end is tilted down at an inclination angle β of 30°. A ratio of a spacing between the lower end of the first-level microwave suppression partition plate 2-2 and a central axis to the inner diameter of the microwave gasification chamber 2 is 1:3. One end of the second-level microwave suppression partition plate 2-3 is connected to an outer wall of the gasification agent chamber 6 and the other end is tilted down at an inclination angle γ of 45°, having a vertical distance 50 mm from an outer end of the first-level microwave suppression partition plate 2-2. A ratio of a spacing between an outer end of the second-level microwave suppression partition plate 2-3 and an outer wall of the microwave gasification chamber 3 to the inner diameter of the microwave gasification chamber 3 is 3:4. A ratio of a height of the microwave gasification chamber 3 to a height of the low-temperature pyrolysis chamber 2 is 2:3. The microwave gasification chamber 3 is connected with the online reforming reaction chamber 4 via a gas phase outlet 3-1 on the upper part of the microwave gasification chamber 3, and connected with the carbon material collection box 11 via a solid outlet 3-2 on the bottom of the microwave gasification chamber 3. The online reforming reaction chamber 4 is connected with the product separation and collection system via a reformed gas outlet 4-1, and a ratio of a height of the reforming reaction chamber 4 to a height of the low-temperature pyrolysis chamber 2 is 4:5.

The combustion heat supply chamber 5 penetrates the interiors of the drying chamber 1 and the low-temperature pyrolysis chamber 2, with its bottom surface of an upper conical frustum structure located between the drying chamber 1 and the low-temperature pyrolysis chamber 2. A ratio of a bottom diameter of the conical frustum structure to an inner diameter of the low-temperature pyrolysis chamber 2 is 2:3. A ratio of a top diameter of the conical frustum structure to the bottom diameter is 1:3, a ratio of the top diameter of the conical frustum structure to a height of the conical frustum structure is 1:1, and a ratio of the top diameter of the conical frustum structure to an inner diameter of a lower combustion chamber body of the combustion heat supply chamber 5 is 1:1. The body of the combustion heat supply chamber 5 is connected with the low-temperature pyrolysis chamber 2 via four circumferentially-symmetrical pyrolysis gas outlets 2-1 of each of four layers. Combustion spray nozzles 5-1 having a diameter of 40 mm and disposed corresponding to the pyrolysis gas outlets 2-1 are disposed on a combustion air supply tube 5-2. A plurality of drying tail gas outlets 5-3 disposed along a bus line at a side of the upper conical frustum structure are connected with the drying chamber 1, and a blower 5-4 is connected with the combustion heat supply chamber 5 via the combustion air supply tube 5-2.

The gasification agent chamber 6 is located on an axis of the microwave gasification chamber 3 and connected with a gasification agent via a bottom gasification agent inlet 6-1 and also connected with the microwave gasification chamber 3 via 6 circumferentially-symmetrical gasification agent outlets 6-2 of each layer, where a bottom air curtain outlet 6-3 is opposed to a peripheral symmetrical feed port 7-2. The hoop direct-feed microwave generator 7 is disposed through an echo suppressor 7-1 on the peripheral symmetrical feed port 7-2 disposed on the microwave gasification chamber 3.

The first-level gas separation device 8 is connected via a reformed gas inlet 8-1 to the reformed gas outlet 4-1 on the online reforming reaction chamber 4, connected with the second-level purification device 9 via a crude hydrogen outlet 8-2, and connected with the gasification agent chamber 6 via a gasification agent outlet 8-3. The second-level purification device 9 is connected with the crude hydrogen outlet 8-2 of the first-level gas separation device 8 via a crude hydrogen inlet 9-1, and connected with the gas storage cylinder 10 via a high-purity hydrogen outlet 9-2.

There is provided a method for co-production of carbon and hydrogen by biomass cascade pyrolysis-microwave gasification by using the above integrated apparatus for co-production of carbon and hydrogen by biomass cascade pyrolysis-microwave gasification, which includes the following steps.

At step S1, the biomass enters the reactor through the drying chamber 1 and is heated and dried by the drying tail gas outlets 5-3, and then enters the low-temperature pyrolysis chamber 2 for low-temperature preliminary pyrolysis and carbonization at the temperature T1 of 350° C.; the pyrolysis gas product enters the combustion heat supply chamber 5 via the pyrolysis gas outlets 2-1, and the remaining solid material enters the microwave gasification chamber 3 through a gap between the first-level microwave suppression partition plate 2-2 and the second-level microwave suppression partition plate 2-3.

At step S2, the material goes through gasification reaction with a gasification agent of separated carbon dioxide or of a gas mixture of separated carbon dioxide and a small amount of other gases in the microwave gasification chamber 3, where the gasification agent is introduced in the form of gaseous state, the mass ratio of the gasification agent to the solid product is 2:1, and the gasification reaction temperature T2 is 900° C.; the gas product enters the online reforming reaction chamber 4 via the upper gas phase outlet 3-1 for online catalytic reforming and then enters the first-level gas separation device 8; the solid porous carbon material product enters the carbon material collection box 11 through the solid outlet 3-2 and is cooled down to below 60° C. in air-isolated state.

At step S3, the pyrolysis gas in the step S1 is combusted in cooperation with the air at the combustion temperature T3 of 1000° C. in the combustion heat supply chamber 5, where an excess air coefficient range is 1.2, the combustion pressure is normal pressure; the generated heat is used to supply heat to the low-temperature pyrolysis chamber 2. The tail gas is discharged into the drying chamber 1 through the drying tail gas outlets 5-3 to dry the biomass feedstock. The reformed gas in the step S2 is separated into crude hydrogen and gasification agent through the first-level gas separation device 8. The gasification agent is returned to the gasification agent chamber 6 and discharged out in two directions to fully contact with the material for microwave gasification reaction, and an air curtain is formed on the surface of the peripheral symmetrical feed port 7-2 by the bottom air curtain outlet 6-3 so as to protect the feed port.

In the step S2, the catalyst in the reforming reaction chamber 4 is prepared in the following steps:

• • (1) selecting nickel nitrate as precursor and weighing urea forming a molar ratio of 1:4 with nickel nitrate, and adding 100 ml of deionized water for dissolution and then stirring uniformly;
  • (2) adding γ-Al₂O₃ powder forming a molar ratio of 3:1 with nickel nitrate and stirring and shaking under the constant temperature of 60° C. at the frequency of 4000 rpm for 10 hours and then taking out for drying;
  • (3) calcining for 2 hours at the temperature of 400° C. in the air atmosphere.

Compared with the conventional thermal energy gasification co-production technology, the hydrogen preparation efficiency of the apparatus in the present disclosure can be increased by about 50 to 80%, the hydrogen production rate can be increased by one or two times, and there is little CO₂ gas in the products, requiring no secondary decarbonization. Further, the carbon nanotube prepared is greatly improved in quality.

The above specific embodiments are used only for describing the technical idea and structural characteristics of the present disclosure to allow the persons familiar with the technology to practice it. The above contents are not intended to limit the scope of protection of the present disclosure. Any equivalent changes or modifications made based on the spirit and essence of the present disclosure shall fall within the scope of protection of the present disclosure.