Wind-solar biomass gasification hydrogen production system and operation method thereof

Abstract

The invention discloses a wind-solar biomass gasification hydrogen production system and an operation method thereof, and the biomass gasification hydrogen production system comprises a biomass gasification furnace which comprises a furnace body, and a gasification agent inlet, a biomass inlet and a converted gas outlet which are arranged on the furnace body; the dust removal and purification device is communicated with the converted gas outlet; the multi-stage catalytic tower comprises a tower body, a converted gas inlet formed in the top end of the tower body, a hydrogen-rich gas outlet formed in the bottom end of the tower body, and more than two stages of catalytic bed layers arranged from the top end of the tower body to the bottom end of the tower body; the catalyst of the first-stage catalytic bed layer is a nickel-based catalyst, and the catalyst of the second-stage catalytic bed layer is a copper or iron-based catalyst. According to the invention, the purpose of preparing high-purity hydrogen through biomass gasification is realized, and the energy conversion efficiency and the hydrogen yield are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of tail gas utilization, and in particular to a wind-solar-biomass gasification hydrogen production system and an operation method thereof. Background Art

[0002] Finding and developing clean, renewable alternative energy sources has become a key direction for global energy development. Biomass, as a renewable energy source, comes from a wide range of sources, including agricultural waste, forestry waste, and municipal waste. It has a low carbon footprint and is renewable. Hydrogen, a green, low-carbon, and widely applicable secondary energy source, is not only efficient, clean, and renewable, but also complements intermittent renewable energy sources like wind and solar power, promoting the diversification and stability of the energy system.

[0003] Biomass gasification hydrogen production technology converts biomass into hydrogen in a high-temperature, oxygen-deficient environment. This not only helps fully utilize biomass resources and reduce dependence on traditional fossil fuels, but also significantly reduces greenhouse gas emissions. Furthermore, green electricity generated from wind and solar power can provide the necessary electrical energy for the biomass gasification hydrogen production process, further enhancing the environmental friendliness of the entire system.

[0004] However, biomass gasification hydrogen production technology currently faces several challenges, including low gasification efficiency, requirements for improved catalytic performance, low hydrogen yield, and inadequate utilization of waste heat generated during the gasification process. Biomass gasification hydrogen production systems involve multiple steps, such as feedstock pretreatment, gasification reaction, catalytic process, and hydrogen separation. Inadequate synergy and optimization between these steps hinders achieving optimal energy efficiency and hydrogen yield for the entire system. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects of low hydrogen yield and low energy conversion efficiency in the existing biomass gasification hydrogen production technology, thereby providing a wind-solar biomass gasification hydrogen production system and its operation method to solve the above problems.

[0006] A biomass gasification hydrogen production system, comprising: Biomass gasification furnace: includes a furnace body, a gasifying agent inlet, a biomass inlet, and a conversion gas outlet arranged on the furnace body; Dust removal and purification device: connected to the conversion gas outlet; Multi-stage catalytic tower: includes a tower body for exchanging heat with the gasifying agent, a reformed gas inlet at the top of the tower body, a hydrogen-rich gas outlet at the bottom of the tower body, and two or more catalytic beds arranged from the top to the bottom of the tower body; The catalyst in the first-stage catalytic bed is a nickel-based catalyst, and the catalyst in the second-stage catalytic bed is a copper- or iron-based catalyst.

[0007] The present invention also includes a catalytic synthesis tower communicated with the hydrogen-rich gas outlet.

[0008] The catalytic synthesis tower comprises a tower body for exchanging heat with a gasifying agent, a hydrogen-rich gas inlet arranged at the top of the tower body, a catalytic gas outlet arranged at the bottom of the tower body, and a catalytic bed layer arranged in the tower body.

[0009] The gasifying agent first exchanges heat with the gas in the catalytic synthesis tower, and then exchanges heat with the gas in the multi-stage catalytic tower. The gasifying agent after heat exchange enters the biomass gasifier through the gasifying agent inlet of the biomass gasifier.

[0010] The catalytic gas outlet of the catalytic synthesis tower is connected to a waste heat recovery device and a purification and refining device.

[0011] The operating method of the biomass gasification hydrogen production system includes: Adding a gasifying agent and biomass into a biomass gasifier to carry out a gasification reaction to generate a crude synthesis gas; The crude synthesis gas is subjected to dust removal and filtration to obtain the conversion gas; The reformed gas is fed into a multi-stage catalytic tower and sequentially passes through the first-stage catalytic bed and the second-stage catalytic bed for catalytic conversion to obtain hydrogen-rich gas; The hydrogen-rich gas is purified to obtain hydrogen with a purity of ≥99%.

[0012] The gasification temperature of the gasification reaction is 600-900° C., and the reaction pressure is 1.1 MPa-1.6 MPa.

[0013] The catalytic temperature of the first-stage catalytic bed is 700°C-810°C, and the reaction pressure is 1.2MPa-1.3MPa; The catalytic temperature of the second-stage catalytic bed is 200-450°C, and the reaction pressure is 0.9MPa-1.1MPa.

[0014] The technical solution of the present invention has the following advantages: 1. This invention cleverly utilizes the waste heat from gasification to perform a step-by-step reforming hydrogen production reaction. Without consuming additional heat sources to maintain the reaction temperature, the hydrogen yield is significantly increased after passing through the first and second catalytic beds. This means that under the same parameters, the present invention can produce more hydrogen, significantly improving hydrogen yield, meeting the growing demand in the hydrogen energy market and providing strong support for the development of the hydrogen energy industry.

[0015] 2. During the biomass gasification process, this invention utilizes green electricity from wind and solar power for the gasifier's startup heating, auxiliary heating, and gas compression and transportation. This not only reduces the expected consumption of fossil fuels and greenhouse gas emissions, but also embodies the synergistic utilization of renewable energy and biomass energy, promoting the optimization of energy structure and sustainable development.

[0016] 3. By utilizing feed gas heat exchange technology, the present invention enables multi-stage catalytic towers and catalytic synthesis towers to fully utilize the heat generated during the reaction to preheat the incoming feed gas. For example, in the steam reforming reaction of carbon monoxide to produce hydrogen, the reaction is exothermic. The generated heat is transferred to the feed gas through a heat exchanger, raising its temperature. This reduces the energy consumption required for external heating, fully utilizes waste heat, and improves the system's energy efficiency.

[0017] 4. The present invention improves energy utilization and product purity by introducing a waste heat recovery device and a purification and refining device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 is a schematic structural diagram of the system of Examples 1-4 of the present invention; Figure 2 It is a structural diagram of the system of Example 5 of the present invention.

[0020] Description of reference numerals: 1-Biomass gasification furnace, 2-Dust removal and purification device, 3-Multi-stage catalytic tower, 4-First-stage catalytic bed, 5-Second-stage catalytic bed, 6-Heat exchanger in the first tower, 7-Heat exchanger in the second tower, 8-Purification and purification device, 9-First regulating valve, 10-Second regulating valve, 11-Third regulating valve, 12-Fourth regulating valve, 13-Waste heat recovery device, 14-Catalytic synthesis tower, 15-Fifth regulating valve. DETAILED DESCRIPTION

[0021] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0022] In the description of the present invention, it should be noted that the terms "side," "upper," "lower," "top," "bottom," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical connections; direct connections or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0024] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] Example 1 A biomass gasification hydrogen production system, such as Figure 1 As shown, it includes a biomass gasifier 1, a dust removal and purification device 2, a multi-stage catalytic tower 3, a waste heat recovery device 13, and a purification and refining device 8. The biomass gasifier 1 includes a furnace body, a gasifying agent inlet, a biomass inlet, and a reformed gas outlet provided on the furnace body. The dust removal and purification device 2 has an inlet and outlet, the inlet of which is connected to the reformed gas outlet of the biomass gasifier 1. The multi-stage catalytic tower 3 includes a tower body for exchanging heat with the gasifying agent, a reformed gas inlet provided at the top of the tower body, a hydrogen-rich gas outlet provided at the bottom of the tower body, and two or more catalytic beds provided from the top to the bottom of the tower body. The catalyst in the first-stage catalytic bed 4 is a nickel-based catalyst, and the catalyst in the second-stage catalytic bed 5 is a copper- or iron-based catalyst. The reformed gas inlet of the multi-stage catalytic tower 3 is connected to the outlet of the dust removal and purification device 2. The hydrogen-rich gas outlet of the multi-stage catalytic tower 3 is connected to the inlet of the waste heat recovery device 13, and the inlet of the purification and refining device 8 is connected to the outlet of the waste heat recovery device 13.

[0026] The multi-stage catalytic tower 3 is further provided with a first in-tower heat exchanger 6 at the location of the first-stage catalytic bed 4, and a second in-tower heat exchanger 7 at the location of the second-stage catalytic bed 5. The gasifying agent is first introduced into the first in-tower heat exchanger 6 and the second in-tower heat exchanger 7 through a first regulating valve 9 and a second regulating valve 10, respectively, to exchange heat with the reformed gas input into the multi-stage catalytic tower 3. The flow rate is controlled by the first regulating valve 9 to keep the reformed gas temperature within the range of 200-400°C at the location of the first-stage catalytic bed 4, and the flow rate is controlled by the second regulating valve 10 to keep the reformed gas temperature within the range of 200-400°C at the location of the second-stage catalytic bed 5. Thus, while the temperature of the raw gasifying agent is increased, the required catalytic temperature of the multi-stage catalytic tower 3 is maintained. Simultaneously, the flow rates of the third regulating valve 11 and the fourth regulating valve 12 are adjusted to control the amount and temperature of the gasifying agent introduced into the biomass gasifier 1.

[0027] In this embodiment, the operating method of the biomass gasification hydrogen production system is based on the above-mentioned process as follows: A fixed-bed gasifier with a diameter of 2 meters and a height of 5 meters was used as biomass gasifier 1. It was filled with pine sawdust biomass feedstock and the gasifying agent was a mixture of steam and air. The steam flow rate was 1000 m³ / h and the air flow rate was 500 m³ / h. The temperature in the gasifier was controlled at 800°C and the reaction pressure was 1.5 MPa. Under these conditions, the pine sawdust biomass feedstock was fully gasified, producing a crude syngas composed of 35% hydrogen, 30% carbon monoxide, 20% carbon dioxide, 10% methane, and 5% other gases. After exiting biomass gasifier 1 at a temperature of 850°C, the crude syngas entered dust removal and purification device 2, where the dust content was reduced to below 5 mg / m³. After separation, the gas temperature was lowered to 800°C before entering the first-stage catalytic bed 4 of a multi-stage catalytic tower 3. The multi-stage catalytic tower 3 was 10 meters high and 2.5 meters in diameter, divided into two sections. The first-stage catalytic bed 4 is loaded with a nickel-based catalyst with a catalyst loading of 5 m³ and a particle diameter of 38 mm. The heat exchanger 6 within the first tower has a heat exchange area of 50 m². The second-stage catalytic bed 5 is loaded with a copper-based catalyst with a catalyst loading of 3 m³ and a particle diameter of 3-8 mm. The heat exchanger 7 within the second tower has a heat exchange area of 40 m².

[0028] After the crude syngas enters the first-stage catalytic bed 4, a nickel-based catalyst reforms methane with steam. This endothermic reaction occurs at a pressure of 1.2 MPa, raising the hydrogen concentration to 42%. The resulting gas enters the first-stage heat exchanger 6, which regulates the temperature of the gas to 350-400°C. This temperature-regulated gas then enters the second-stage catalytic bed 5, where a copper-based catalyst further reforms carbon monoxide with steam to produce hydrogen. This exothermic reaction occurs at a pressure of 1.0 MPa, raising the hydrogen concentration to 55%. The second-stage heat exchanger 7 maintains the reaction temperature at 350-400°C. The resulting gas then enters the waste heat recovery unit 13 and the purification unit 8, ultimately producing hydrogen with a purity exceeding 99%.

[0029] During the operation of biomass gasification, the startup heating, auxiliary heating of the gasifier, as well as gas compression and transportation, all use green electricity provided by wind and solar power.

[0030] Example 2 The difference between this embodiment and embodiment 1 is that the parameter conditions of the operating method are different. The specific process is as follows: A fluidized bed gasifier with a diameter of 1.8 meters and a height of 4.5 meters was selected as the biomass gasifier 1. It was loaded with rice husk biomass feedstock, and the gasifying agent was a mixture of water vapor and oxygen, with a water vapor flow rate of 900 m³ / h and an oxygen flow rate of 350 m³ / h. The temperature in the gasifier was controlled at 700°C, and the reaction pressure was 1.1 MPa. Under these conditions, the rice husk biomass feedstock was fully gasified, producing a crude syngas composed of 33% hydrogen, 32% carbon monoxide, 20% carbon dioxide, 10% methane, and 5% other gases. After exiting the gasifier at a temperature of 740°C, the crude syngas entered the dust removal and purification unit 2, where the dust content was reduced to below 5 mg / m³. After separation, the gas temperature was lowered to 700°C before entering the first-stage catalytic bed 4 of the multi-stage catalytic tower 3. The multi-stage catalytic tower 3 was 9 meters high, 2.2 meters in diameter, and divided into two sections. The first-stage catalytic bed 4 is loaded with a nickel-based catalyst with a catalyst loading of 4.5 m³ and a particle diameter of 5 mm. The heat exchange area of the heat exchanger 6 in the first tower is 45 m². The second-stage catalytic bed 5 is loaded with a copper-based catalyst with a catalyst loading of 3 m³ and a particle diameter of 4 mm. The heat exchange area of the heat exchanger 7 in the second tower is 35 m².

[0031] The crude synthesis gas enters the first-stage catalytic bed 4. Over the nickel-based catalyst, methane and water vapor undergo a reforming reaction. This is an endothermic reaction at a pressure of 1.2 MPa. The concentration of the generated hydrogen increases to 36%. The post-reaction gas enters the first-stage heat exchanger 6, which adjusts the temperature of the post-reaction gas to 200-400°C. The temperature-regulated gas enters the second-stage catalytic bed 5. Over the copper-based catalyst, carbon monoxide and water vapor undergo a further reforming reaction to produce hydrogen. The reaction temperature is 200-400°C. This is an exothermic reaction at a pressure of 0.9 MPa, further increasing the hydrogen concentration to 48%. The post-reaction gas enters the waste heat recovery device 13 and the purification and refining device 8. The final hydrogen purity can reach over 99%.

[0032] During the biomass gasification operation, the startup heating, auxiliary heating of the gasifier, as well as gas compression and transportation all use green electricity provided by wind and solar power, realizing green energy drive for the entire system.

[0033] Example 3 The difference between this embodiment and embodiment 1 is that the parameter conditions of the operating method are different. The specific process is as follows: A circulating fluidized bed gasifier with a diameter of 2.2 meters and a height of 5.5 meters was used as the biomass gasifier 1. It was loaded with wheat straw biomass feedstock and the gasifying agent was a mixture of steam and air. The steam flow rate was 1200 m³ / h and the air flow rate was 400 m³ / h. The temperature in the gasifier was controlled at 820°C and the reaction pressure was 1.6 MPa. Under these conditions, the wheat straw biomass feedstock was fully gasified, producing a crude syngas composed of 32% hydrogen, 33% carbon monoxide, 23% carbon dioxide, 10% methane, and 12% other gases. After exiting the gasifier at a temperature of 870°C, the crude syngas entered the dust removal and purification unit 2, where the dust content was reduced to below 5 mg / m³. After separation, the gas temperature was lowered to 780°C before entering the first-stage catalytic bed 4 of the multi-stage catalytic tower 3. The multi-stage catalytic tower 3 was 11 meters high and 2.8 meters in diameter, divided into two sections. The first-stage catalytic bed 4 is loaded with a nickel-based catalyst with a catalyst loading of 6 m³ and a particle diameter of 7 mm. The heat exchanger 6 within the first tower has a heat exchange area of 60 m². The second-stage catalytic bed 5 is loaded with an iron-based catalyst with a catalyst loading of 4 m³ and a particle diameter of 6 mm. The heat exchanger 7 within the second tower has a heat exchange area of 50 m².

[0034] The crude synthesis gas enters the first-stage catalytic bed 4. Under the action of the nickel-based catalyst, methane and water vapor undergo a reforming reaction. This reaction is endothermic and the reaction pressure is 1.3 MPa. The concentration of the generated hydrogen increases to 40%. The post-reaction gas enters the first-stage heat exchanger 6, which adjusts the temperature of the post-reaction gas to 350-400°C. The temperature-regulated gas enters the second-stage catalytic bed 5. Under the action of the iron-based catalyst, carbon monoxide and water vapor further undergo a reforming reaction to produce hydrogen. The reaction temperature is 350-400°C. This reaction is exothermic and the reaction pressure is 1.1 MPa. The hydrogen concentration further increases to 49%. The post-reaction gas enters the waste heat recovery device 13 and the purification and refining device 8. The final hydrogen purity can reach over 99%.

[0035] During the biomass gasification operation, the startup heating, auxiliary heating, and gas compression and transportation of the gasifier all use green electricity provided by wind and solar power, realizing green energy drive for the entire system.

[0036] Example 4 The difference between this embodiment and embodiment 1 is that the parameter conditions of the operating method are different. The specific process is as follows: A fixed-bed gasifier with a diameter of 2.5 meters and a height of 6 meters was used as biomass gasifier 1. Cotton stalk biomass feedstock was loaded into the gasifier, and the gasifying agent was a mixture of steam and air. The steam flow rate was 1100 m³ / h, and the air flow rate was 450 m³ / h. The temperature in the gasifier was controlled at 820°C, and the reaction pressure was 1.4 MPa. Under these conditions, the cotton stalk biomass feedstock was fully gasified, producing a crude syngas composed of 34% hydrogen, 31% carbon monoxide, 22% carbon dioxide, 11% methane, and 12% other gases. After exiting the gasifier at a temperature of 860°C, the crude syngas entered dust removal and purification device 2, where the dust content was reduced to below 5 mg / m³. The separated gas temperature was then lowered to 810°C. It then entered the first-stage catalytic bed 4 of a multi-stage catalytic tower 3, which was 10.5 meters high and 2.7 meters in diameter, and divided into two sections. The first-stage catalytic bed 4 is loaded with a nickel-based catalyst with a catalyst loading of 5.5 m³ and a particle diameter of 4-7 mm. The heat exchanger 6 within the first tower has a heat exchange area of 55 m². The second-stage catalytic bed 5 is loaded with a copper-based catalyst with a catalyst loading of 3.5 m³ and a particle diameter of 3-6 mm. The heat exchanger 7 within the second tower has a heat exchange area of 45 m².

[0037] The crude synthesis gas enters the first-stage catalytic bed 4. Over the nickel-based catalyst, methane and water vapor undergo a reforming reaction. This reaction is endothermic and operates at a pressure of 1.25 MPa. The resulting hydrogen concentration increases to 44%. The heat exchanger 6 in the first tower adjusts the temperature of the post-reaction gas to 300-400°C. The temperature-regulated gas enters the second-stage catalytic bed 5. Over the copper-based catalyst, carbon monoxide and water vapor undergo a further exothermic reforming reaction to produce hydrogen at a temperature of 300-400°C and a pressure of 1.05 MPa. The hydrogen concentration further increases to 54%. The heat exchanger 7 in the second tower maintains the reaction temperature at 300-400°C. The post-reaction gas enters the waste heat recovery unit 13 and the purification and refining unit 8. The resulting hydrogen purity can reach over 99%.

[0038] During the biomass gasification operation, the startup heating, auxiliary heating of the gasifier, as well as gas compression and transportation all use green electricity provided by wind and solar power, realizing green energy drive for the entire system.

[0039] Example 5 A biomass gasification hydrogen production system, such as Figure 2 As shown, it includes a biomass gasification furnace 1, a dust removal and purification device 2, a multi-stage catalytic tower 3, a catalytic synthesis tower 14, a waste heat recovery device 13, and a purification and refining device 8. Among them, the biomass gasification furnace 1 includes a furnace body, a gasification agent inlet, a biomass inlet, and a conversion gas outlet arranged on the furnace body. The dust removal and purification device 2 has an inlet and an outlet, and the inlet is connected to the conversion gas outlet of the biomass gasification furnace 1. The multi-stage catalytic tower 3 includes a tower body for exchanging heat with the gasification agent, a conversion gas inlet arranged at the top of the tower body, a hydrogen-rich gas outlet arranged at the bottom of the tower body, and more than two levels of catalytic beds arranged from the top to the bottom of the tower body; among them, the catalyst of the first-stage catalytic bed 4 is a nickel-based catalyst, and the catalyst of the second-stage catalytic bed 5 is a copper or iron-based catalyst; the conversion gas inlet of the multi-stage catalytic tower 3 is connected to the outlet of the dust removal and purification device 2. The catalytic synthesis tower 14 includes a tower body, a hydrogen-rich gas inlet arranged at the top of the tower body, a catalytic gas outlet arranged at the bottom of the tower body, and a catalytic bed arranged in the tower body; the catalyst in the catalytic bed in the catalytic synthesis tower 14 is a copper-based catalyst; the hydrogen-rich gas inlet of the catalytic synthesis tower 14 is connected to the hydrogen-rich gas outlet of the multi-stage catalytic tower 3, the catalytic gas outlet of the catalytic synthesis tower 14 is connected to the inlet of the waste heat recovery device 13, and the inlet of the purification and refining device 8 is connected to the outlet of the waste heat recovery device 13.

[0040] A third in-tower heat exchanger is provided at the position of the catalytic bed of the catalytic synthesis tower 14, a first in-tower heat exchanger 6 is provided at the position of the first-stage catalytic bed 4 of the multi-stage catalytic tower 3, and a second in-tower heat exchanger 7 is provided at the position of the second-stage catalytic bed 5. The gasifying agent is first regulated by the fifth regulating valve 15 before entering the third heat exchanger of the catalytic synthesis tower 14, where it exchanges heat with the hydrogen-rich gas from the multi-stage catalytic tower 3. After heat exchange, the gasifying agent is mixed with a gasifying agent from another source and then passed through the first regulating valve 9 and the second regulating valve 10, respectively, into the first heat exchanger 6 and the second heat exchanger 7, where it exchanges heat with the reformed gas entering the multi-stage catalytic tower 3. The flow rate is controlled by the first regulating valve 9 to keep the reformed gas temperature within the range of 200-400°C at the first-stage catalytic bed 4, and by the second regulating valve 10 to keep the reformed gas temperature within the range of 200-400°C at the second-stage catalytic bed 5. This ensures that the required catalytic temperature of the multi-stage catalytic tower 3 is maintained while increasing the temperature of the raw gasifying agent. Simultaneously, the flow rates of the third regulating valve 11 and the fourth regulating valve 12 are adjusted to control the amount and temperature of the gasifying agent entering the biomass gasifier 1.

[0041] Biomass feedstock is fed into a biomass gasifier 1, where a gasifying agent (a mixture of water vapor and oxygen / air) is introduced. A gasification reaction occurs within the gasifier, producing crude syngas. The crude syngas passes through a dust removal and purification device 2 to remove dust particles, resulting in relatively clean syngas. The clean syngas enters the first section of a multi-stage catalytic tower 3, where methane and water vapor reform over a nickel-based catalyst in the first-stage catalytic bed 4 to produce hydrogen and carbon monoxide. A heat exchanger within the first tower regulates the gas temperature. The regulated gas then enters the second section of the multi-stage catalytic tower 3, where carbon monoxide and water vapor further reform over a copper- or iron-based catalyst in the second-stage catalytic bed 5 to produce hydrogen-rich gas. A heat exchanger within the second tower regulates the reaction temperature. After exiting the multi-stage catalytic tower 3, the hydrogen-rich gas enters a purification and refining device 8, where it undergoes purification processes such as decarbonization to produce a high-purity hydrogen product. The first, second, third, and fourth regulating valves 9, 10, 11, and 12 are used to regulate the inlet and outlet flow rates of the gasifying agent (a mixture of water vapor and oxygen / air). For gases that remain unreacted after passing through the multi-stage catalytic tower 3, an n-stage catalytic synthesis tower, such as the catalytic synthesis tower 14 in this embodiment, can be added to further increase hydrogen yield.

[0042] In this embodiment, the operating method of the biomass gasification hydrogen production system is based on the above-mentioned process as follows: A fixed-bed gasifier with a diameter of 2 meters and a height of 5 meters was used as biomass gasifier 1. It was filled with pine sawdust biomass feedstock and the gasifying agent was a mixture of steam and air. The steam flow rate was 1000 m³ / h and the air flow rate was 500 m³ / h. The temperature in the gasifier was controlled at 800°C and the reaction pressure was 1.5 MPa. Under these conditions, the pine sawdust biomass feedstock was fully gasified, producing a crude syngas composed of 35% hydrogen, 30% carbon monoxide, 20% carbon dioxide, 10% methane, and 5% other gases. After exiting biomass gasifier 1 at a temperature of 850°C, the crude syngas entered dust removal and purification device 2, where the dust content was reduced to below 5 mg / m³. After separation, the gas temperature was lowered to 800°C before entering the first-stage catalytic bed 4 of a multi-stage catalytic tower 3. The multi-stage catalytic tower 3 was 10 meters high and 2.5 meters in diameter, divided into two sections. The first-stage catalytic bed 4 is loaded with a nickel-based catalyst with a catalyst loading of 5 m³ and a particle diameter of 38 mm. The heat exchanger 6 within the first tower has a heat exchange area of 50 m². The second-stage catalytic bed 5 is loaded with a copper-based catalyst with a catalyst loading of 3 m³ and a particle diameter of 3-8 mm. The heat exchanger 7 within the second tower has a heat exchange area of 40 m².

[0043] After the crude syngas enters the first-stage catalytic bed 4, a nickel-based catalyst reforms methane with steam. This endothermic reaction occurs at a pressure of 1.2 MPa, raising the hydrogen concentration to 42%. The resulting gas enters the first-stage heat exchanger 6, which adjusts the temperature of the gas to 350-400°C. This temperature-regulated gas enters the second-stage catalytic bed 5, where a copper-based catalyst further reforms carbon monoxide with steam to produce hydrogen. This exothermic reaction occurs at a pressure of 1.0 MPa, further increasing the hydrogen concentration to 55%. The second-stage heat exchanger 7 maintains the reaction temperature at 350-400°C.

[0044] The hydrogen-rich gas discharged from the second internal heat exchanger 7 of the multi-stage catalytic tower 3 is fed into the catalytic synthesis tower 14. This tower 14 utilizes a fixed-bed gasifier with a diameter of 2.5 meters and a height of 5 meters. The catalytic bed in this tower is loaded with a copper catalyst with a catalyst loading of 3 m³ and a particle diameter of 3-8 mm. A third internal heat exchanger with a heat exchange area of 40 m², located at the catalyst bed level, is installed in this tower. Once the hydrogen-rich gas enters the catalytic synthesis tower 14, it undergoes a further hydrogen reforming reaction with steam over the copper-based catalyst. The reaction temperature is 350-400°C, and the reaction pressure is 1.0 MPa. The hydrogen concentration is further increased to 60%. The post-reaction gas enters the waste heat recovery unit 13 and the purification unit 8, ultimately producing hydrogen with a purity exceeding 99%.

[0045] During the operation of biomass gasification, the startup heating, auxiliary heating of the gasifier, as well as gas compression and transportation, all use green electricity provided by wind and solar power.

[0046] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A biomass gasification hydrogen production system, characterized in that: include: Biomass gasification furnace: includes a furnace body, a gasifying agent inlet, a biomass inlet, and a conversion gas outlet arranged on the furnace body; Dust removal and purification device: connected to the conversion gas outlet; Multi-stage catalytic tower: includes a tower body, a reformed gas inlet at the top of the tower body, a hydrogen-rich gas outlet at the bottom of the tower body, and two or more catalytic beds arranged from the top to the bottom of the tower body; The catalyst in the first-stage catalytic bed is a nickel-based catalyst, and the catalyst in the second-stage catalytic bed is a copper- or iron-based catalyst.

2. The hydrogen production system according to claim 1, characterized in that: The invention also includes a catalytic synthesis tower communicated with the hydrogen-rich gas outlet.

3. The hydrogen production system according to claim 2, characterized in that: The catalytic synthesis tower comprises a tower body, a hydrogen-rich gas inlet arranged at the top of the tower body, a catalytic gas outlet arranged at the bottom of the tower body, and a catalytic bed layer arranged in the tower body.

4. The hydrogen production system according to claim 3, characterized in that: The gasifying agent first exchanges heat with the gas in the catalytic synthesis tower, and then exchanges heat with the gas in the multi-stage catalytic tower. The gasifying agent after heat exchange enters the biomass gasifier through the gasifying agent inlet of the biomass gasifier.

5. The hydrogen production system according to any one of claims 2 to 4, characterized in that: The catalytic gas outlet of the catalytic synthesis tower is connected to a waste heat recovery device and a purification and refining device.

6. The method for operating the hydrogen production system according to any one of claims 1 to 5, characterized in that: include: Adding a gasifying agent and biomass into a biomass gasifier to carry out a gasification reaction to generate a crude synthesis gas; The crude synthesis gas is subjected to dust removal and filtration to obtain the conversion gas; The reformed gas is fed into a multi-stage catalytic tower and sequentially passes through the first-stage catalytic bed and the second-stage catalytic bed for catalytic conversion to obtain hydrogen-rich gas; The hydrogen-rich gas is purified to obtain hydrogen with a purity of ≥99%.

7. The operating method according to claim 6, characterized in that: The gasification temperature of the gasification reaction is 600-900° C., and the reaction pressure is 1.1 MPa-1.6 MPa.

8. The operating method according to claim 6 or 7, characterized in that: The catalytic temperature of the first-stage catalytic bed is 700° C.-810° C., and the reaction pressure is 1.2 MPa-1.3 MPa.

9. The operating method according to claim 6 or 7, characterized in that: The catalytic temperature of the second-stage catalytic bed is 200-450° C., and the reaction pressure is 0.9 MPa-1.1 MPa.

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