Green hydrogen coupled biomass hydrogasification furnace system and hydrogasification method

Abstract

The invention belongs to the technical field of biomass gasification production, and particularly relates to a green hydrogen coupled biomass hydrogasification furnace system and hydrogasification method.The system comprises a biomass gasification furnace, and a furnace cavity of the biomass gasification furnace is sequentially divided into a drying layer, a hydropyrolysis layer, a hydrogasification layer, a reduction gasification layer and an oxidation slag layer from top to bottom; a biomass feeding hole is formed in the top of the biomass gasification furnace, and a spiral stirring mechanism is arranged in the center of the biomass feeding hole. The spiral stirring mechanisms are arranged on the drying layer and the hydropyrolysis layer which are most prone to generating tar, materials are mechanically crushed and stirred, bed blockage caused by biomass raw material bonding and tar foam is effectively prevented, and stable operation of the gasifier is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of biomass gasification production technology, specifically relating to a biomass hydrogenation gasification furnace system coupled with green hydrogen and a hydrogenation gasification method. Background Technology

[0002] Biomass energy, as the only renewable carbon source, has attracted much attention for its efficient and clean utilization. However, traditional biomass gasification technology has obvious limitations: in conventional air / oxygen gasification processes, the methane content in the syngas is usually less than 10%, and it contains a large amount of nitrogen or carbon dioxide, resulting in low calorific value and high costs for subsequent purification and utilization; at the same time, the tar problem generated during the gasification process has long plagued the stable operation of the system.

[0003] Hydromethanation technology provides a new pathway for the efficient conversion of biomass. Compared with traditional gasification, hydromethanation, with the participation of hydrogen, allows the gasification reaction to proceed under relatively mild temperature conditions (700-900℃). This not only alters the tar formation pathway and effectively inhibits the production of heavy tar, but also promotes the formation and retention of light tar (such as BTX and other light aromatics), thereby increasing the economic value of the products. Simultaneously, hydrogen directly participates in the methane synthesis reaction (CO + 3H₂ → CH₄ + H₂O and C + 2H₂ → CH₄, etc.), significantly increasing the methane content in the crude syngas and substantially reducing the scale and energy consumption of subsequent methanation units.

[0004] However, existing hydrogenation methanation technologies still face challenges. First, the hydrogen source issue urgently needs to be addressed: using fossil fuels to produce hydrogen contradicts the low-carbon principles of biomass utilization, while the supply of byproduct hydrogen is unstable and its purity is limited. The emergence of green hydrogen (hydrogen produced through renewable energy electrolysis of water) provides an ideal hydrogen source for hydrogenation methanation. Green hydrogen not only has zero carbon emissions during its production process, but its high-purity oxygen byproduct can also be used as a gasifying agent, maximizing resource utilization. Compared to gray hydrogen (hydrogen produced from fossil fuels), green hydrogen ensures a low-carbon industrial chain; compared to byproduct hydrogen, green hydrogen has a stable supply and guaranteed purity.

[0005] Regarding reactors, existing technologies such as patents CN202510758538A and CN202411319704A often employ fluidized bed reactors (such as bubbling fluidized beds and risers) for biomass hydrogenation and gasification. While these technologies offer high gas-solid contact efficiency and good heat and mass transfer, they also have inherent drawbacks: First, fluidized beds typically require complex material circulation systems (such as cyclone separators and return mechanisms) and large amounts of inert bed material, resulting in complex system structures, high investment costs, and high operating energy consumption. Second, to achieve stable fluidization, biomass feedstocks are usually required to be processed into particles with uniform size and regular shape, increasing feedstock pretreatment costs and energy consumption.

[0006] In contrast, the fixed-bed (moving-bed) coal hydrogasification technology disclosed in patent CN116144404A exhibits unique advantages. This technology uses a simple moving-bed reactor, integrating multiple reaction zones such as oxidative slag, reduction gasification, hydrogasification methanation, and hydropyrolysis into a single vertical furnace chamber, achieving staged conversion of coal. Its advantages lie in the elimination of complex material circulation systems and inert bed materials, compact equipment structure, high operational reliability, and easier large-scale scaling. By introducing hydrogen and reactants at different temperature zones, the reaction path can be flexibly controlled to achieve the directional generation of products (methane, BTX light aromatics, and light oils). However, when directly applied to biomass feedstocks, it reveals serious incompatibilities, mainly because biomass contains a large amount of volatiles, which rapidly precipitate large amounts of tar in the hydropyrolysis layer, clogging the upper solid bed and gas channels. Summary of the Invention

[0007] This invention addresses the aforementioned problems by providing a biomass hydrogenation gasification furnace system and hydrogenation gasification method coupled with green hydrogen. The system aims to integrate the advantages of a moving bed reactor, such as its simple structure and ease of scale-up, while simultaneously solving the core problem of tar clogging the bed when applied to biomass feedstocks through a spiral stirring mechanism and a specific gasifier tilt angle design. This allows the biomass feedstock to flow smoothly under gravity, effectively preventing bridging. Furthermore, the system directly introduces green hydrogen as the core reaction medium and hydrogen source into the gasification process, utilizing its high purity and zero-carbon properties to ensure the low-carbon nature of the process from the source. It also systematically integrates the byproduct oxygen from green hydrogen as a gasifying agent, maximizing the utilization of renewable energy resources and constructing a complete low-carbon chain from green electricity to green hydrogen to green fuels / chemicals. This achieves efficient, stable, and continuous hydrogenation gasification of biomass feedstocks, producing high-methane-content syngas and high-value-added light aromatics (BTX and PCX).

[0008] To achieve the above objectives, the present invention employs the following technical solution: A biomass hydrogenation gasification furnace system coupled with green hydrogen includes a biomass gasification furnace. The furnace chamber of the biomass gasification furnace is divided into a drying layer, a hydrogenation pyrolysis layer, a hydrogenation gasification layer, a reduction gasification layer, and an oxidized slag layer from top to bottom. A biomass feed inlet is provided at the top of the biomass gasification furnace, and a spiral stirring mechanism is provided at the center of the biomass feed inlet. A first air inlet, a second air inlet, and a third air inlet are arranged from bottom to top on the side wall of the biomass gasification furnace. A gasification gas outlet is provided above the side wall of the gasifier, and a slag gas inlet, a slag pool water inlet, and a slag pool water outlet are provided below the side wall of the biomass gasifier. A slag discharge port is provided at the bottom of the biomass gasifier. The first, second, and third gas inlets are respectively located in the hydropyrolysis layer, the hydrogasification layer, and the oxidized slag layer. The reduction gasification layer is located between the second and third gas inlets, and the drying layer is located between the first gas inlet and the gasification gas outlet. The gasification gas outlet is connected to the inlet of the water washing tower via a pipeline, and the outlet of the water washing tower is connected to the inlet of the gas-liquid separator via a pipeline; the liquid outlets of both the water washing tower and the gas-liquid separator are connected to the tar collector; the outlet of the gas-liquid separator is connected to the gas separation unit; the gas purification and separation unit includes a low-temperature methanol washing unit and a cryogenic separation unit connected in sequence. The CO2 gas separated by the low-temperature methanol washing unit and the H2 and CO gas separated by the cryogenic separation unit are all pressurized and transported to the second air inlet and slag gas inlet of the biomass gasification furnace through a circulating gas compressor.

[0009] Furthermore, it also includes a water electrolyzer, the hydrogen outlet of which is connected to the first and second air inlets of the biomass gasifier, and the oxygen outlet of which is connected to the third air inlet and the slag gas inlet of the biomass gasifier.

[0010] Furthermore, the arrangement range of the stirring blades of the spiral stirring mechanism corresponds to the drying layer and pyrolysis layer regions of the biomass gasification furnace.

[0011] Furthermore, the height-to-diameter ratio of the biomass gasifier is 10-30:1.

[0012] Furthermore, the vertical distance between the first air inlet and the top of the biomass gasifier is 1 / 6 to 1 / 4 of the height of the biomass gasifier; the vertical distance between the second air inlet and the top of the biomass gasifier is 1 / 3 to 1 / 2 of the height of the biomass gasifier; and the vertical distance between the third air inlet and the top of the biomass gasifier is 2 / 3 to 3 / 4 of the height of the biomass gasifier.

[0013] Furthermore, the middle part of the biomass gasifier furnace cavity consists of two conical sections. The upper conical section is connected to the biomass feed inlet at the top, and the lower conical section is connected to the slag discharge outlet at the bottom. The angle α between the generatrix of the upper conical section and the axis of the biomass gasifier is 1-20°, and the angle β between the generatrix of the lower conical section and the axis of the biomass gasifier is 1-20°. The inner wall of the lower conical section is provided with a conical refractory castable layer, and the angle γ between the generatrix of its upper inclined surface and the axis of the biomass gasifier is 30-60°.

[0014] Furthermore, the slag pool water inlet and outlet are located below the molten slag gas inlet, and are used to inject quench water into the bottom ash collection area to quench and solidify the molten ash falling from the oxidized slag layer; the slag pool water inlet and outlet are connected to the external black water treatment system to form a quench water circulation.

[0015] A method for hydrogenation gasification includes the following steps: S1: Biomass feedstock with a particle size of 5-50mm and a moisture content of less than 15wt% is added into the biomass gasifier through the biomass feed inlet and stirred and distributed by a spiral stirring mechanism; the first gasifying agent, the second gasifying agent, and the third gasifying agent are fed into the furnace through the first air inlet, the second air inlet, and the third air inlet, respectively; at the same time, quench water is injected into the furnace bottom through the slag pool water inlet; S2: The third gasifying agent introduced from the third air inlet reacts with the downward gasification residue in the oxidized slag layer to produce high-temperature molten ash and oxygen-rich combustion gas. The reaction temperature is 1200-1500℃. The molten ash is cooled and solidified by the quench water at the bottom of the furnace and then discharged through the slag discharge port. S3: The oxygen-rich combustion gas produced by S2 reacts with the downward-flowing semi-coke in the reducing gasification layer to produce reducing gases mainly composed of CO and H2. The reaction temperature is 1000-1200℃. S4: The second gasifying agent introduced from the second air inlet undergoes hydrogenation and methanation reactions with the reducing gas generated by S3 and the downward pyrolysis semi-coke in the hydrogenation gasification layer, generating methane-containing gas. The reaction temperature is 700-1000℃. S5: The first gasifying agent introduced from the first air inlet undergoes a hydrogenation and pyrolysis reaction with the downward biomass feedstock in the hydrogenation and pyrolysis layer, generating gaseous products containing methane and light oil, with a reaction temperature of 500-700℃. S6: The gaseous products generated by the gasifier are discharged from the gasification gas outlet and successively cooled and washed by the water washing tower. After gas-liquid separation by the gas-liquid separator, the purified gas enters the low-temperature methanol washing unit and the cryogenic separation unit for deep separation. S7: Methane product gas is obtained from the cryogenic separation unit; the CO2 gas removed by the low-temperature methanol washing unit and the H2 and CO mixture separated by the cryogenic separation unit are pressurized by the circulating gas compressor and split into two streams. The first stream of circulating gas is returned to the second inlet of the biomass gasifier as part of the gasifying agent, and the second stream of circulating gas is sent into the furnace as slag gas through the slag gas inlet to regulate the local temperature and atmosphere at the slag discharge port and alleviate the risk of slagging of biomass ash; the liquid products generated during the water washing and gas-liquid separation process are sent to the tar collector for oil-water separation to obtain light oil products.

[0016] Furthermore, in S1, the operating pressure of the biomass gasifier is 0-6 MPa; the first gasifying agent is hydrogen; the second gasifying agent is a mixture of hydrogen and the first circulating gas; and the third gasifying agent is oxygen and water vapor.

[0017] Furthermore, in S1, the ratio of oxygen to biomass feed in the third gasifying agent is 0.2-0.8 Nm³. 3 / kg; the ratio of hydrogen to biomass feed in the second gasifying agent is 0.2-1.2 Nm³. 3 / kg; the ratio of hydrogen to biomass feed in the first gasifying agent is 0-1.2 Nm 3 / kg.

[0018] Furthermore, the product composition can be controlled by adjusting the reaction temperature of the hydrogasification layer: when the reaction temperature is controlled above 900℃, methane is produced in abundance; when the reaction temperature is controlled between 700-900℃, light oil products such as BTX and PCX are produced in abundance.

[0019] Compared with the prior art, the present invention has the following advantages: 1. This invention innovatively couples a green hydrogen preparation system with a biomass gasification system, using green hydrogen as a hydrogen source and oxygen as a gasifying agent, thus ensuring low carbon emissions throughout the entire process from the source.

[0020] 2. This invention, by setting a spiral stirring mechanism in the drying layer and the hydropyrolysis layer, which are most prone to tar generation, mechanically crushes and stirs the materials, effectively preventing the adhesion of biomass raw materials and bed blockage caused by tar foam, thus ensuring the stable operation of the gasifier.

[0021] 3. This invention significantly improves the utilization rate of carbon atoms by recycling CO2, H2 and CO separated from syngas purification, and realizes the efficient recycling of carbon resources within the system.

[0022] 4. This invention allows for flexible control of product composition by precisely controlling the reaction temperature of the hydrogasification layer. High temperatures (>900℃) tend to produce abundant methane, while medium to low temperatures (700-900℃) are conducive to the production of high-value light oil products such as BTX and PCX, thus enhancing the economic adaptability of the process.

[0023] 5. This invention integrates multiple reaction zones into a single gasifier, eliminating the complex material circulation system and large amount of inert bed material required by fluidized beds. The system structure is greatly simplified, and equipment investment and operating energy consumption are significantly reduced. Attached Figure Description

[0024] Figure 1 This is a process flow diagram of the present invention; Figure 2 This is a schematic diagram of the biomass gasification furnace in this invention; In the diagram, 1-water electrolyzer; 2-biomass gasifier; 3-water washing tower; 4-gas-liquid separator; 5-low temperature methanol washing unit; 6-cryogenic separation unit; 7-circulating gas compressor; 8-tar collector; 201-spiral stirring mechanism; 202-biomass feed inlet; 203-first air inlet; 204-second air inlet; 205-third air inlet; 206-slag gas inlet; 207-slag pool water inlet; 208-slag discharge port; 209-slag pool water outlet; 210-conical refractory castable layer; 211-gasification gas outlet. Detailed Implementation

[0025] To further illustrate the technical solution of the present invention, the present invention will be further described below through embodiments. Example

[0026] like Figure 1 and Figure 2As shown, a biomass hydrogenation gasification furnace system coupled with green hydrogen includes a water electrolyzer 1 and a biomass gasifier 2. The biomass gasifier 2 adopts a moving bed design, and the height-to-diameter ratio of the biomass gasifier 2 is 10:1. The middle part of the furnace cavity of the biomass gasifier 2 has two conical sections. The upper conical section is connected to the top biomass feed inlet 202, and the lower conical section is connected to the bottom slag discharge outlet 208. The angle α between the generatrix of the upper conical section and the axis of the biomass gasifier 2 is 10°, and the angle β between the generatrix of the lower conical section and the axis of the biomass gasifier 2 is 15°. This structure facilitates the smooth downward flow of biomass feedstock by gravity and prevents bridging. The inner wall of the conical section is provided with a conical refractory castable layer 210, the angle γ between the generatrix of its upper inclined surface and the axis of the biomass gasifier 2 is 45°. The furnace cavity of the biomass gasifier 2 is divided into a drying layer, a hydropyrolysis layer, a hydrogasification layer, a reduction gasification layer, and an oxidized slag layer from top to bottom. A biomass feed inlet 202 is provided at the top of the biomass gasifier 2, and a spiral stirring mechanism 201 is provided at the center of the biomass feed inlet 202. The stirring blades of the spiral stirring mechanism 201 are arranged in the range corresponding to the drying layer and the pyrolysis layer area of ​​the biomass gasifier 2, and are used to crush the material, distribute the material evenly, and mechanically disturb the area during feeding. To prevent tar adhesion caused by the volatilization of biomass feedstock and effectively ensure unobstructed gas flow, a first air inlet 203, a second air inlet 204, and a third air inlet 205 are sequentially arranged from bottom to top on the side wall of the biomass gasifier 2. The vertical distance between the first air inlet 203 and the top of the biomass gasifier 2 is 1 / 5 of the height of the biomass gasifier 2; the vertical distance between the second air inlet 204 and the top of the biomass gasifier 2 is 2 / 5 of the height of the biomass gasifier 2; and the vertical distance between the third air inlet 205 and the top of the biomass gasifier 2 is [missing information - likely a percentage]. The biomass gasifier 2 has a gasification gas outlet 211 located above the side wall of the gasifier 2, which is 3 / 4 of the height of the gasifier. A slag gas inlet 206, a slag pool water inlet 207, and a slag pool water outlet 209 are located below the side wall of the gasifier 2. The slag pool water inlet 207 and the slag pool water outlet 209 are located below the slag gas inlet 206 and are used to inject quench water into the bottom ash collection area to quench and solidify the molten ash falling from the oxidized slag layer. The slag pool water inlet 207 and the slag pool water outlet 209 are connected to an external black water treatment system to form a quench water circulation system. A slag discharge port 208 is located at the bottom of the biomass gasifier 2.The first air inlet 203, the second air inlet 204, and the third air inlet 205 are respectively disposed in the hydropyrolysis layer, the hydrogasification layer, and the oxidized slag layer. The reduction gasification layer is located between the second air inlet 204 and the third air inlet 205. The drying layer is located between the first air inlet 203 and the gasification gas outlet 211. The hydrogen outlet of the water electrolysis cell 1 is connected to the first air inlet 203 and the second air inlet 204 of the biomass gasifier 2. The oxygen outlet of the water electrolysis cell 1 is connected to the third air inlet 205 and the slag gas inlet 206 of the biomass gasifier 2. The gasification gas outlet 211 is connected to the inlet of the water washing tower 3 via a pipeline, and the outlet of the water washing tower 3 is connected to the inlet of the gas-liquid separator 4 via a pipeline; the liquid outlets of both the water washing tower 3 and the gas-liquid separator 4 are connected to the tar collector 8; the outlet of the gas-liquid separator 4 is connected to the gas separation unit; the gas purification and separation unit includes a low-temperature methanol washing unit 5 and a cryogenic separation unit 6 connected in sequence. The CO2 gas separated by the low-temperature methanol washing unit 5 and the H2 and CO gas separated by the cryogenic separation unit 6 are pressurized and transported to the second air inlet 204 and the slag gas inlet 206 of the biomass gasification furnace 2 through the circulating gas compressor 7.

[0027] A method for hydrogenation gasification includes the following steps: S1: The operating pressure of the biomass gasifier 2 is 4 MPa; biomass feedstock with a particle size of 10-30 mm and a moisture content of less than 10 wt% is continuously added into the biomass gasifier 2 through the biomass feed inlet 202, and is stirred and distributed by the spiral stirring mechanism 201; the first gasifying agent, the second gasifying agent, and the third gasifying agent are fed into the furnace through the first air inlet 203, the second air inlet 204, and the third air inlet 205, respectively. The first gasifying agent is hydrogen; the second gasifying agent is a mixture of hydrogen and the first circulating gas; the third gasifying agent is oxygen and water vapor, and the ratio of oxygen to biomass feedstock in the third gasifying agent is 0.6 Nm. 3 / kg; the ratio of hydrogen to biomass feed in the second gasifying agent is 0.6 Nm³. 3 / kg; the ratio of hydrogen to biomass feed in the first gasifying agent is 0.2 Nm³. 3 / kg; at the same time, quench water is injected into the furnace bottom through the slag pool water inlet 207; S2: The third gasifying agent introduced from the third air inlet 205 reacts with the downward gasification residue in the oxidized slag layer to produce high-temperature molten ash and oxygen-rich combustion gas. The reaction temperature is 1350℃, ensuring that the ash melts and flows to achieve liquid slag discharge. The molten ash is cooled and solidified by the furnace bottom quench water and then discharged through the slag discharge port 208. S3: The oxygen-rich combustion gas produced by S2 reacts with the downward-flowing semi-coke in the reducing gasification layer to produce reducing gas mainly composed of CO and H2. The reaction temperature is 1100℃. S4: The second gasifying agent introduced from the second air inlet 204 undergoes hydrogenation and methanation reactions with the reducing gas generated by S3 and the downward pyrolysis semi-coke in the hydrogenation gasification layer, generating methane-containing gas. The reaction temperature is 800℃.

[0028] S5: The first gasifying agent introduced from the first air inlet 203 undergoes a hydrogenation pyrolysis reaction with the downward biomass feedstock in the hydrogenation pyrolysis layer to generate gaseous products containing methane and light oil. The reaction temperature is 600℃. S6: The gaseous products generated by the gasifier are discharged from the gasification gas outlet 211, and are successively cooled and washed by the water washing tower 3. After gas-liquid separation by the gas-liquid separator 4, the purified gas enters the low-temperature methanol washing unit 5 and the cryogenic separation unit 6 for deep separation. S7: Methane product gas is obtained from cryogenic separation unit 6; the CO2 gas removed by cryogenic methanol washing unit 5 and the H2 and CO mixture separated by cryogenic separation unit 6 are pressurized by circulating gas compressor 7 and split into two streams. The first stream of circulating gas is returned to the second air inlet 204 of biomass gasifier 2 as part of the gasifying agent, and the second stream of circulating gas is sent into the furnace as slag gas through slag gas inlet 206 to regulate the local temperature and atmosphere at the slag discharge port and alleviate the risk of slagging of biomass ash. This achieves efficient recycling of carbon and hydrogen elements and improves the overall carbon conversion rate and economy; the liquid products generated during water washing and gas-liquid separation are sent to tar collector 8 for oil-water separation to obtain light oil products.

[0029] Based on the aforementioned system and process conditions, experimental research was conducted using sawdust as raw material. The experimental results showed that the crude gas exiting the gasifier contained 25-35% CH4, 40-50% H2, 15-20% CO, and 5-10% CO2. Simultaneously, the yield of light oil products (BTX, PCX) recovered in tar collector 8 reached 26-30% of the biomass feed, and the methane content was significantly increased compared to traditional biomass gasification technology. Example

[0030] In this embodiment, a biomass hydrogenation gasification furnace system coupled with green hydrogen is provided. The biomass gasification furnace 2 has a height-to-diameter ratio of 15:1. The angle α between the generatrix of the upper conical section and the axis of the biomass gasification furnace 2 is 5°, and the angle β between the generatrix of the lower conical section and the axis of the biomass gasification furnace 2 is 5°. The inner wall of the lower conical section is provided with a conical refractory castable layer 210, and the angle γ between the generatrix of its upper inclined surface and the axis of the biomass gasification furnace 2 is 55°. The vertical distance between the first air inlet 203 and the top of the biomass gasification furnace 2 is 1 / 6 of the height of the biomass gasification furnace 2; the vertical distance between the second air inlet 204 and the top of the biomass gasification furnace 2 is 1 / 3 of the height of the biomass gasification furnace 2; and the vertical distance between the third air inlet 205 and the top of the biomass gasification furnace 2 is 2 / 3 of the height of the biomass gasification furnace 2.

[0031] A method for hydrogenation gasification includes the following steps: S1: The operating pressure of the biomass gasifier 2 is 4.5 MPa; biomass feedstock with a particle size of 10-30 mm and a moisture content of less than 10 wt% is continuously added into the biomass gasifier 2 through the biomass feed inlet 202, and is stirred and distributed by the spiral stirring mechanism 201; the first gasifying agent, the second gasifying agent, and the third gasifying agent are fed into the furnace through the first air inlet 203, the second air inlet 204, and the third air inlet 205, respectively. The first gasifying agent is hydrogen; the second gasifying agent is a mixture of hydrogen and the first circulating gas; the third gasifying agent is oxygen and water vapor, and the ratio of oxygen to biomass feedstock in the third gasifying agent is 0.5 Nm. 3 / kg; the ratio of hydrogen to biomass feed in the second gasifying agent is 0.8 Nm³. 3 / kg; the ratio of hydrogen to biomass feed in the first gasifying agent is 0.3 Nm³. 3 / kg; at the same time, quench water is injected into the furnace bottom through the slag pool water inlet 207; S2: The third gasifying agent introduced from the third air inlet 205 reacts with the downward gasification residue in the oxidized slag layer to produce high-temperature molten ash and oxygen-rich combustion gas. The reaction temperature is 1300℃, ensuring that the ash melts and flows to achieve liquid slag discharge. The molten ash is cooled and solidified by the furnace bottom quench water and then discharged through the slag discharge port 208. S3: The oxygen-rich combustion gas produced by S2 reacts with the downward-flowing semi-coke in the reducing gasification layer to produce reducing gas mainly composed of CO and H2. The reaction temperature is 1050℃. S4: The second gasifying agent introduced from the second air inlet 204 undergoes hydrogenation and methanation reactions with the reducing gas generated by S3 and the downward pyrolysis semi-coke in the hydrogenation gasification layer, generating methane-containing gas. The reaction temperature is 750℃.

[0032] S5: The first gasifying agent introduced from the first air inlet 203 undergoes a hydrogenation pyrolysis reaction with the downward biomass feedstock in the hydrogenation pyrolysis layer to generate gaseous products containing methane and light oil. The reaction temperature is 550℃. S6: The gaseous products generated by the gasifier are discharged from the gasification gas outlet 211, and are successively cooled and washed by the water washing tower 3. After gas-liquid separation by the gas-liquid separator 4, the purified gas enters the low-temperature methanol washing unit 5 and the cryogenic separation unit 6 for deep separation. S7: Methane product gas is obtained from cryogenic separation unit 6; the CO2 gas removed by cryogenic methanol washing unit 5 and the H2 and CO mixture separated by cryogenic separation unit 6 are pressurized by circulating gas compressor 7 and split into two streams. The first stream of circulating gas is returned to the second air inlet 204 of biomass gasifier 2 as part of the gasifying agent, and the second stream of circulating gas is sent into the furnace as slag gas through slag gas inlet 206 to regulate the local temperature and atmosphere at the slag discharge port and alleviate the risk of slagging of biomass ash. This achieves efficient recycling of carbon and hydrogen elements and improves the overall carbon conversion rate and economy; the liquid products generated during water washing and gas-liquid separation are sent to tar collector 8 for oil-water separation to obtain light oil products.

[0033] Based on the aforementioned system and process conditions, experimental research was conducted using sawdust as raw material. Experimental results showed that the crude gas at the gasifier outlet contained 25-32% CH4, 38-48% H2, 12-18% CO, and 4-8% CO2. Simultaneously, the yield of light oils (BTX, PCX) recovered in tar collector 8 reached 26-35% of the biomass feed. Compared to Example 1, the tar yield was improved after adjusting the height-to-diameter ratio, angle, and inlet position. The system operated stably without bed blockage or slagging, demonstrating the good adaptability of the system to sawdust raw materials under different structural parameters. Example

[0034] In this embodiment, a biomass hydrogenation gasification furnace system coupled with green hydrogen is provided. The biomass gasification furnace 2 has a height-to-diameter ratio of 20:1. The angle α between the generatrix of the upper conical section and the axis of the biomass gasification furnace 2 is 15°, and the angle β between the generatrix of the lower conical section and the axis of the biomass gasification furnace 2 is 15°. The inner wall of the lower conical section is provided with a conical refractory castable layer 210, and the angle γ between the generatrix of its upper inclined surface and the axis of the biomass gasification furnace 2 is 35°. The vertical distance between the first air inlet 203 and the top of the biomass gasification furnace 2 is 1 / 4 of the height of the biomass gasification furnace 2; the vertical distance between the second air inlet 204 and the top of the biomass gasification furnace 2 is 1 / 2 of the height of the biomass gasification furnace 2; and the vertical distance between the third air inlet 205 and the top of the biomass gasification furnace 2 is 3 / 4 of the height of the biomass gasification furnace 2.

[0035] A method for hydrogenation gasification includes the following steps: S1: The operating pressure of the biomass gasifier 2 is 2.5 MPa; biomass feedstock with a particle size of 10-40 mm and a moisture content of less than 10 wt% is continuously added into the biomass gasifier 2 through the biomass feed inlet 202, and is stirred and distributed by the spiral stirring mechanism 201; the first gasifying agent, the second gasifying agent, and the third gasifying agent are fed into the furnace through the first air inlet 203, the second air inlet 204, and the third air inlet 205, respectively. The first gasifying agent is hydrogen; the second gasifying agent is a mixture of hydrogen and the first circulating gas; the third gasifying agent is oxygen and water vapor, and the ratio of oxygen to biomass feedstock in the third gasifying agent is 0.3 Nm. 3 / kg; the ratio of hydrogen to biomass feed in the second gasifying agent is 0.4 Nm³. 3 / kg; the ratio of hydrogen to biomass feed in the first gasifying agent is 1.0 Nm³. 3 / kg; at the same time, quench water is injected into the furnace bottom through the slag pool water inlet 207; S2: The third gasifying agent introduced from the third air inlet 205 reacts with the downward gasification residue in the oxidized slag layer to produce high-temperature molten ash and oxygen-rich combustion gas. The reaction temperature is 1250℃, ensuring that the ash melts and flows to achieve liquid slag discharge. The molten ash is cooled and solidified by the furnace bottom quench water and then discharged through the slag discharge port 208. S3: The oxygen-rich combustion gas produced by S2 reacts with the downward-flowing semi-coke in the reducing gasification layer to produce reducing gas mainly composed of CO and H2. The reaction temperature is 1000℃. S4: The second gasifying agent introduced from the second air inlet 204 undergoes hydrogenation and methanation reactions with the reducing gas generated by S3 and the downward pyrolysis semi-coke in the hydrogenation gasification layer, generating methane-containing gas. The reaction temperature is 850℃.

[0036] S5: The first gasifying agent introduced from the first air inlet 203 undergoes a hydrogenation pyrolysis reaction with the downward biomass feedstock in the hydrogenation pyrolysis layer to generate gaseous products containing methane and light oil. The reaction temperature is 650℃. S6: The gaseous products generated by the gasifier are discharged from the gasification gas outlet 211, and are successively cooled and washed by the water washing tower 3. After gas-liquid separation by the gas-liquid separator 4, the purified gas enters the low-temperature methanol washing unit 5 and the cryogenic separation unit 6 for deep separation. S7: Methane product gas is obtained from cryogenic separation unit 6; the CO2 gas removed by cryogenic methanol washing unit 5 and the H2 and CO mixture separated by cryogenic separation unit 6 are pressurized by circulating gas compressor 7 and split into two streams. The first stream of circulating gas is returned to the second air inlet 204 of biomass gasifier 2 as part of the gasifying agent, and the second stream of circulating gas is sent into the furnace as slag gas through slag gas inlet 206 to regulate the local temperature and atmosphere at the slag discharge port and alleviate the risk of slagging of biomass ash. This achieves efficient recycling of carbon and hydrogen elements and improves the overall carbon conversion rate and economy; the liquid products generated during water washing and gas-liquid separation are sent to tar collector 8 for oil-water separation to obtain light oil products.

[0037] Based on the aforementioned system and process conditions, an experimental study was conducted using straw as raw material. The experimental results showed that the crude gas exiting the gasifier contained 25-30% CH4, 35-45% H2, 20-25% CO, and 8-12% CO2. Simultaneously, the yield of light oil products (BTX, PCX) recovered in tar collector 8 reached 20-30% of the biomass feed. Example

[0038] In this embodiment, a biomass hydrogenation gasification furnace system coupled with green hydrogen is provided. The biomass gasification furnace 2 has a height-to-diameter ratio of 25:1. The angle α between the generatrix of the upper conical section and the axis of the biomass gasification furnace 2 is 20°, and the angle β between the generatrix of the lower conical section and the axis of the biomass gasification furnace 2 is 20°. The inner wall of the lower conical section is provided with a conical refractory castable layer 210, and the angle γ between the generatrix of its upper inclined surface and the axis of the biomass gasification furnace 2 is 30°. The vertical distance between the first air inlet 203 and the top of the biomass gasification furnace 2 is 1 / 4 of the height of the biomass gasification furnace 2; the vertical distance between the second air inlet 204 and the top of the biomass gasification furnace 2 is 1 / 3 of the height of the biomass gasification furnace 2; and the vertical distance between the third air inlet 205 and the top of the biomass gasification furnace 2 is 2 / 3 of the height of the biomass gasification furnace 2.

[0039] A method for hydrogenation gasification includes the following steps: S1: The operating pressure of the biomass gasifier 2 is 1.5 MPa; biomass feedstock with a particle size of 10-40 mm and a moisture content of less than 15 wt% is continuously added into the biomass gasifier 2 through the biomass feed inlet 202, and is stirred and distributed by the spiral stirring mechanism 201; the first gasifying agent, the second gasifying agent, and the third gasifying agent are fed into the furnace through the first air inlet 203, the second air inlet 204, and the third air inlet 205, respectively. The first gasifying agent is hydrogen; the second gasifying agent is a mixture of hydrogen and the first circulating gas; the third gasifying agent is oxygen and water vapor, and the ratio of oxygen to biomass feedstock in the third gasifying agent is 0.4 Nm. 3 / kg; the ratio of hydrogen to biomass feed in the second gasifying agent is 0.2 Nm³. 3 / kg; the ratio of hydrogen to biomass feed in the first gasifying agent is 0.8 Nm³. 3 / kg; at the same time, quench water is injected into the furnace bottom through the slag pool water inlet 207; S2: The third gasifying agent introduced from the third air inlet 205 reacts with the downward gasification residue in the oxidized slag layer to produce high-temperature molten ash and oxygen-rich combustion gas. The reaction temperature is 1280℃, ensuring that the ash melts and flows to achieve liquid slag discharge. The molten ash is cooled and solidified by the furnace bottom quench water and then discharged through the slag discharge port 208. S3: The oxygen-rich combustion gas produced by S2 reacts with the downward-flowing semi-coke in the reducing gasification layer to produce reducing gas mainly composed of CO and H2. The reaction temperature is 1050℃. S4: The second gasifying agent introduced from the second air inlet 204 undergoes hydrogenation and methanation reactions with the reducing gas generated by S3 and the downward pyrolysis semi-coke in the hydrogenation gasification layer, generating methane-containing gas. The reaction temperature is 820℃.

[0040] S5: The first gasifying agent introduced from the first air inlet 203 undergoes a hydrogenation pyrolysis reaction with the downward biomass feedstock in the hydrogenation pyrolysis layer to generate gaseous products containing methane and light oil. The reaction temperature is 630℃. S6: The gaseous products generated by the gasifier are discharged from the gasification gas outlet 211, and are successively cooled and washed by the water washing tower 3. After gas-liquid separation by the gas-liquid separator 4, the purified gas enters the low-temperature methanol washing unit 5 and the cryogenic separation unit 6 for deep separation. S7: Methane product gas is obtained from cryogenic separation unit 6; the CO2 gas removed by cryogenic methanol washing unit 5 and the H2 and CO mixture separated by cryogenic separation unit 6 are pressurized by circulating gas compressor 7 and split into two streams. The first stream of circulating gas is returned to the second air inlet 204 of biomass gasifier 2 as part of the gasifying agent, and the second stream of circulating gas is sent into the furnace as slag gas through slag gas inlet 206 to regulate the local temperature and atmosphere at the slag discharge port and alleviate the risk of slagging of biomass ash. This achieves efficient recycling of carbon and hydrogen elements and improves the overall carbon conversion rate and economy; the liquid products generated during water washing and gas-liquid separation are sent to tar collector 8 for oil-water separation to obtain light oil products.

[0041] Based on the aforementioned system and process conditions, an experimental study was conducted using straw as raw material. The experimental results showed that the crude gas exiting the gasifier contained 25-28% CH4, 32-40% H2, 19-26% CO, and 7-12% CO2. Simultaneously, the yield of light oil products (BTX, PCX) recovered in tar collector 8 reached 18-26% of the biomass feed.

[0042] Based on the experimental results of the above embodiments, the system of the present invention exhibits the following significant technical advantages: In the above embodiments, the methane content remained above 25%, significantly higher than that of traditional gasification technologies. Light oil, as a valuable byproduct, further improved the process economy. Furthermore, the introduction of green hydrogen enabled the entire process to achieve near-zero carbon emissions.

[0043] During the entire 72-hour continuous operation, no shutdowns occurred due to tar blockage or severe slagging, proving the effectiveness of the spiral stirring mechanism and optimized furnace structure in solving the challenges of biomass moving bed gasification. Through tail gas recirculation, the system's carbon conversion rate exceeded 98%, and the cold gas efficiency reached over 75%, demonstrating excellent energy conversion efficiency and low-carbon characteristics.

[0044] The above embodiments fully demonstrate the significant progress and industrial application potential of the system and method provided by the present invention in achieving efficient, stable, and low-carbon conversion of biomass.

[0045] The foregoing has shown and described the main features and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0046] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A biomass hydrogenation gasification furnace system coupled with green hydrogen, characterized in that: The system includes a biomass gasifier (2), the furnace chamber of which is divided into a drying layer, a hydropyrolysis layer, a hydrogasification layer, a reduction gasification layer and an oxidized slag layer from top to bottom; a biomass feed inlet (202) is provided at the top of the biomass gasifier (2), and a spiral stirring mechanism (201) is provided at the center of the biomass feed inlet (202); a first air inlet (203), a second air inlet (204) and a third air inlet (205) are provided from bottom to top on the side wall of the biomass gasifier (2); and a gasification gas outlet (21) is provided above the side wall of the biomass gasifier (2). 1) A slag gas inlet (206), a slag pool water inlet (207), and a slag pool water outlet (209) are provided below the side wall of the biomass gasifier (2), and a slag discharge port (208) is provided at the bottom of the biomass gasifier (2); the first air inlet (203), the second air inlet (204), and the third air inlet (205) are respectively provided in the hydropyrolysis layer, the hydrogasification layer, and the oxidized slag layer, the reduction gasification layer is located between the second air inlet (204) and the third air inlet (205), and the drying layer is located between the first air inlet (203) and the gasification gas outlet (211); The gas outlet (211) of the gasification gas is connected to the inlet of the water washing tower (3) through a pipeline, and the outlet of the water washing tower (3) is connected to the inlet of the gas-liquid separator (4) through a pipeline; the liquid outlets of the water washing tower (3) and the gas-liquid separator (4) are both connected to the tar collector (8); the outlet of the gas-liquid separator (4) is connected to the gas separation unit; the gas purification and separation unit includes a low-temperature methanol washing unit (5) and a cryogenic separation unit (6) connected in sequence. The CO2 gas separated by the low-temperature methanol washing unit (5) and the H2 and CO gas separated by the cryogenic separation unit (6) are pressurized and transported to the second air inlet (204) and slag gas inlet (206) of the biomass gasifier (2) through the circulating gas compressor (7).

2. The biomass hydrogenation gasification furnace system coupled with green hydrogen according to claim 1, characterized in that: It also includes a water electrolyzer (1), the hydrogen outlet of which is connected to the first air inlet (203) and the second air inlet (204) of the biomass gasifier (2), and the oxygen outlet of which is connected to the third air inlet (205) and the slag gas inlet (206) of the biomass gasifier (2).

3. The biomass hydrogenation gasification furnace system coupled with green hydrogen according to claim 2, characterized in that: The range of the stirring blades of the spiral stirring mechanism (201) corresponds to the drying layer and pyrolysis layer regions of the biomass gasifier (2).

4. The biomass hydrogenation gasification furnace system coupled with green hydrogen according to claim 3, characterized in that: The height-to-diameter ratio of the biomass gasifier (2) is 10-30:

1.

5. A biomass hydrogenation gasification furnace system coupled with green hydrogen according to claim 4, characterized in that: The vertical distance between the first air inlet (203) and the top of the biomass gasifier (2) is 1 / 6 to 1 / 4 of the height of the biomass gasifier (2); the vertical distance between the second air inlet (204) and the top of the biomass gasifier (2) is 1 / 3 to 1 / 2 of the height of the biomass gasifier (2); and the vertical distance between the third air inlet (205) and the top of the biomass gasifier (2) is 2 / 3 to 3 / 4 of the height of the biomass gasifier (2).

6. The biomass hydrogenation gasification furnace system coupled with green hydrogen according to claim 5, characterized in that: The middle part of the furnace cavity of the biomass gasifier (2) consists of two conical sections. The upper conical section is connected to the biomass feed port (202) at the top, and the lower conical section is connected to the slag discharge port (208) at the bottom. The angle α between the generatrix of the upper conical section and the axis of the biomass gasifier (2) is 1-20°, and the angle β between the generatrix of the lower conical section and the axis of the biomass gasifier (2) is 1-20°. The inner wall of the lower conical section is provided with a conical refractory castable layer (210), and the angle γ between the generatrix of its upper inclined surface and the axis of the biomass gasifier (2) is 30-60°.

7. A biomass hydrogenation gasification furnace system coupled with green hydrogen according to claim 6, characterized in that: The slag pool water inlet (207) and slag pool water outlet (209) are located below the molten slag gas inlet (206) and are used to inject quench water into the bottom ash collection area to quench and solidify the molten ash falling from the oxidized slag layer. The slag pool water inlet (207) and slag pool water outlet (209) are connected to the external black water treatment system to form a quench water circulation.

8. A method for hydrogenation gasification, using the biomass hydrogenation gasification furnace system coupled with green hydrogen as described in claim 7, characterized in that: Includes the following steps: S1: Biomass raw materials with a particle size of 5-50mm and a moisture content of less than 15wt% are added into the biomass gasifier (2) through the biomass feed inlet (202) and stirred and distributed by the spiral stirring mechanism (201); the first gasifying agent, the second gasifying agent and the third gasifying agent are fed into the furnace through the first air inlet (203), the second air inlet (204) and the third air inlet (205) respectively; at the same time, quench water is injected into the bottom of the furnace through the slag pool water inlet (207); S2: The third gasifying agent introduced from the third air inlet (205) reacts with the downward gasification residue in the oxidized slag layer to produce high-temperature molten ash and oxygen-rich combustion gas. The reaction temperature is 1200-1500℃. The molten ash is cooled and solidified by the furnace bottom quench water and then discharged through the slag discharge port (208). S3: The oxygen-rich combustion gas produced by S2 reacts with the downward-flowing semi-coke in the reducing gasification layer to produce reducing gases mainly composed of CO and H2. The reaction temperature is 1000-1200℃. S4: The second gasifying agent introduced from the second air inlet (204) undergoes hydrogenation and methanation reactions with the reducing gas generated by S3 and the downward pyrolysis semi-coke in the hydrogenation gasification layer, generating methane-containing gas. The reaction temperature is 700-1000℃. S5: The first gasifying agent introduced from the first air inlet (203) undergoes a hydrogenation pyrolysis reaction with the downward biomass feedstock in the hydrogenation pyrolysis layer to generate gaseous products containing methane and light oil. The reaction temperature is 500-700℃. S6: The gaseous products generated by the gasifier are discharged from the gasification gas outlet (211), and are successively cooled and washed by the water washing tower (3). After gas-liquid separation by the gas-liquid separator (4), the purified gas is sent to the low-temperature methanol washing unit (5) and the cryogenic separation unit (6) for deep separation. S7: Obtain methane product gas from cryogenic separation unit (6); the CO2 gas removed by cryogenic methanol washing unit (5) and the H2 and CO mixture separated by cryogenic separation unit (6) are pressurized by circulating gas compressor (7) and split into two streams. The first stream of circulating gas is returned to the second air inlet (204) of biomass gasifier (2) as part of the gasifying agent. The second stream of circulating gas is sent into the furnace as slag gas through slag gas inlet (206) to adjust the local temperature and atmosphere of the slag discharge port and alleviate the risk of slagging of biomass ash. The liquid products generated during water washing and gas-liquid separation are sent to tar collector (8) for oil-water separation to obtain light oil products.

9. The hydrogasification method according to claim 8, characterized in that: In S1, the operating pressure of the biomass gasifier (2) is 0-6 MPa; the first gasifying agent is hydrogen; the second gasifying agent is a mixture of hydrogen and the first circulating gas; and the third gasifying agent is oxygen and water vapor.

10. A hydrogasification method according to claim 8, characterized in that: In step S1, the ratio of oxygen to biomass feed in the third gasifying agent is 0.2-0.8 Nm. 3 / kg; the ratio of hydrogen to biomass feed in the second gasifying agent is 0.2-1.2 Nm³. 3 / kg; the ratio of hydrogen to biomass feed in the first gasifying agent is 0-1.2 Nm 3 / kg.

11. A hydrogasification method according to claim 8, characterized in that: The product composition can be controlled by adjusting the reaction temperature of the hydrogasification layer: when the reaction temperature is controlled above 900℃, methane is produced in abundance; when the reaction temperature is controlled between 700-900℃, light oil products such as BTX and PCX are produced in abundance.

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