Method for co-producing hydrogen-rich synthesis gas and hard carbon material by biomass transient high-temperature gasification

Abstract

The invention discloses a method for co-producing hydrogen-rich synthesis gas and a hard carbon material through biomass transient high-temperature gasification, and belongs to the technical field of biomass resource utilization and electrochemical energy storage materials. The method comprises the following steps: mixing a biomass raw material, a conductive additive and water according to a specific mass ratio, and carrying out ball milling and high-pressure molding to obtain a low-resistivity conductive blank; in a vacuum environment, through primary Joule heating, the green body is transiently heated until gasification is completed, and hydrogen-rich synthesis gas and primary porous carbon are synchronously collected; and mixing and molding the primary porous carbon and a binder, and carrying out secondary Joule heating until carbonization and hole sealing to obtain the hard carbon material. Through precise regulation and control of the two-step Joule heating process, synergistic efficient conversion of the biomass to the hydrogen-rich synthesis gas and the hard carbon material is achieved, and the method has the advantages of being high in reaction rate, high in energy efficiency, free of chemical additives, high in product value and the like and is suitable for large-scale industrial application.

Description

Technical Field

[0001] This invention belongs to the field of biomass high-value utilization and electrochemical energy storage material preparation technology, specifically involving a method for simultaneously converting biomass into high-quality hydrogen-rich syngas and high-performance hard carbon materials based on a two-step Joule heating technology. Background Technology

[0002] Biomass, as an abundant renewable hydrocarbon resource, plays a vital role in alleviating the energy crisis and developing a circular economy through its efficient and clean conversion. Traditional biomass gasification technologies (such as fluidized bed and fixed bed) are mainly used to produce syngas, but they generally suffer from problems such as low reaction temperature (usually 800-1200℃), slow heating rate (≤10℃ / s), high wood tar production leading to pipeline blockage, and low purity of gaseous products. Furthermore, the added value of solid by-products (crude char) is low, making it difficult to fully utilize the resources.

[0003] Hard carbon materials have become a core candidate for sodium-ion battery anode materials due to their wide availability, low cost, and excellent sodium storage performance. An ideal hard carbon material needs abundant closed-pore structures, suitable interlayer spacing, and low specific surface area, but its performance is highly dependent on the microstructure control during the preparation process. Existing hard carbon preparation technologies mostly employ slow pyrolysis carbonization of agricultural and forestry waste, which suffers from drawbacks such as long reaction cycles (several hours to tens of hours), high energy consumption, and uncontrollable product structures. These technologies typically require complex subsequent chemical treatments such as activation and doping, which not only increase process costs but may also introduce environmental pollution, making it difficult to simultaneously achieve product performance consistency and high added value.

[0004] Joule heating technology, with its advantages of instantaneous ultra-high temperature and rapid heating rate, has been applied to the synthesis of carbon materials such as graphene. However, existing technologies are mostly focused on the preparation of single products, and there are no reports on its use to regulate the microstructure of hard carbon and simultaneously achieve the synergistic conversion of biomass into hydrogen-rich syngas and high-performance hard carbon materials.

[0005] Therefore, developing a rapid, efficient, green, and environmentally friendly biomass conversion technology that can co-produce clean energy and high-end carbon materials has become an urgent technical problem to be solved in this field. Summary of the Invention

[0006] In view of this, the present invention aims to overcome the shortcomings of existing biomass gasification technologies, such as low product quality, low value of solid by-products, and complex hard carbon preparation processes, high energy consumption, and difficulty in performance control. It provides a method for the co-production of hydrogen-rich syngas and hard carbon materials through transient high-temperature biomass gasification. Through the precise design of a two-step Joule heating process, continuous control of the "gasification pore-forming - carbonization pore-sealing" process is achieved, simultaneously obtaining high-quality hydrogen-rich syngas and high-performance hard carbon materials, thereby enhancing the comprehensive utilization value of biomass resources.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0008] The primary objective of this invention is to provide a method for the transient high-temperature gasification of biomass to co-produce hydrogen-rich syngas and hard carbon materials, comprising the following steps:

[0009] S1: By mass ratio Biomass raw materials, conductive additives, and water are mixed and then ball-milled into a slurry. The conductive blank is formed by pressing under pressure.

[0010] S2: Place the conductive blank in a vacuum environment with an absolute pressure lower than 1000 Pa, so as to A direct current is applied at a specific current density to induce a single-stage Joule heating, causing the conductive blank to heat up to [temperature value missing] within 1.0-2 seconds. And maintain for 3-7 seconds to complete biomass gasification;

[0011] S3: Collect the hydrogen-rich synthesis gas and primary porous carbon produced in step S2, mix the primary porous carbon and binder at a mass ratio of 10:(1.5-3), ball mill and form to obtain a secondary green body;

[0012] S4: Place the secondary preform in a protective atmosphere or vacuum environment, so as to A direct current is applied at a certain current density to perform secondary Joule heating, which raises the temperature of the secondary blank to 1150-1250℃ within 1-3 seconds and holds it at that temperature for 10-30 seconds to obtain hard carbon material.

[0013] As a further improvement to the above technical solution, in step S1, the conductive additive is biochar or recycled carbon powder produced by the system itself; the resistivity of the conductive blank is .

[0014] As a further improvement to the above technical solution, in step S1, the biomass raw material is one or more of bamboo powder, sawdust, rice husk, or straw, and the original resistivity of the biomass raw material is higher than that of bamboo powder, sawdust, rice husk, or straw. .

[0015] As a further improvement to the above technical solution, in step S2, the absolute pressure of the vacuum environment is 50-200 Pa; the current of the first-stage Joule heating rises to the preset value within 0.5-1.0 seconds.

[0016] As a further improvement to the above technical solution, in step S3, the binder is wood tar or bio-oil; the slurry after mixing the primary porous carbon and the binder is ball-milled and then pressed into shape under a pressure of 150-300 MPa; the specific surface area of ​​the primary porous carbon is... After two-stage Joule heating, the specific surface area of ​​the hard carbon material decreased to [a value missing]. The interlayer spacing is .

[0017] As a further improvement to the above technical solution, in step S4, the protective atmosphere is nitrogen or argon; the heating rate of the secondary Joule heating is greater than... .

[0018] As a further improvement to the above technical solution, the yield of the hard carbon material is... At a current density of 0.1C, the reversible specific capacity in the first cycle is no less than .

[0019] As a further improvement to the above technical solution, the total yield of the hydrogen-rich syngas is not less than 1200 mL / g, of which the hydrogen yield is not less than 700 mL / g, and the syngas contains... The sum of the volume concentrations of CO and CO is not less than 95%.

[0020] As a further improvement to the above technical solution, in step S2, the current density of the first-stage Joule heating is... The vaporization temperature is 1200-1400℃; in step S4, the current density of the secondary Joule heating is... The carbonization temperature is .

[0021] A second objective of the present invention is to provide a system for implementing the above-described method, comprising a primary Joule heating reactor, a gas collection and purification system, a mixing and molding device, a secondary Joule heating reactor, and a solid collection device;

[0022] The primary Joule heating reactor is used to realize the gasification reaction in step S2, and its outlet is connected to the gas collection and purification system and the mixing and forming device, respectively.

[0023] The mixing and molding device is used to complete the mixing and molding in step S3, and its outlet is connected to a secondary Joule heating reactor.

[0024] The secondary Joule heating reactor is used to realize the carbonization reaction in step S4, and its outlet is connected to a solid collection device.

[0025] Both the primary Joule heating reactor and the secondary Joule heating reactor are equipped with a vacuum system and a programmable DC power supply.

[0026] Compared with the prior art, the present invention has significant advantages and beneficial effects, specifically reflected in the following aspects:

[0027] 1. This invention utilizes a two-step Joule heating process to simultaneously prepare hydrogen-rich syngas and high-performance hard carbon materials, solving the problems of single-product output and low resource utilization efficiency in traditional technologies. In the hydrogen-rich syngas... With a concentration of ≥95% and a hydrogen yield of ≥700mL / g, the first-cycle reversible specific capacity of hard carbon materials is ≥370mAh / g (bamboo-based products can reach 391mAh / g). Both types of products have extremely high industrial application value, achieving synergistic co-production of high-value products.

[0028] 2. Both core reactions are completed within seconds, with a heating rate exceeding 1000℃ / s. Energy is highly concentrated, heat loss is minimal, and the production of 1kg of hard carbon material consumes only about 18kWh of electricity, far lower than the energy consumption of traditional pyrolysis processes. The entire process requires no chemical activators, dopants, or other additives; product performance is optimized solely through physical proportions and temperature control. There are no pollutant emissions, aligning with green production principles.

[0029] 3. First-stage Joule heating and ultra-high temperature gasification enable efficient biomass conversion and pore-forming of porous carbon precursors. Second-stage Joule heating achieves pore sealing and structural rearrangement through rapid carbonization, forming a hard carbon microstructure suitable for sodium storage. By adjusting parameters such as current density, temperature, and holding time, the specific surface area, interlayer spacing, and closed-pore ratio of the hard carbon material, as well as the composition and yield of the syngas, can be precisely controlled to meet the needs of different application scenarios.

[0030] 4. This invention is applicable to a variety of biomass raw materials such as bamboo powder, sawdust, rice husks, and straw, which are widely available and inexpensive. The process flow only includes mixing, molding, two-step Joule heating, and product collection, without the need for complex pretreatment and post-treatment steps. It requires little equipment investment, is easy to operate, and is readily achievable for large-scale industrial continuous production. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the process flow of the method for co-producing hydrogen-rich syngas and hard carbon anode material by transient high-temperature pyrolysis of biomass based on Joule heating in an embodiment of the present invention.

[0032] Figure 2 This is a schematic diagram of the half-cell test results of the hard carbon anode material prepared from bamboo powder by the method described in this embodiment of the invention;

[0033] Figure 3 This is a schematic diagram of the system structure for the co-production of hydrogen-rich syngas and hard carbon anode material by transient high-temperature pyrolysis of biomass based on Joule heating in an embodiment of the present invention.

[0034] Explanation of reference numerals in the attached figures:

[0035] 10 - Primary Joule heating reactor; 20 - Gas collection and purification system; 30 - Mixing and molding device; 40 - Secondary Joule heating reactor; 50 - Solid collection device. Detailed Implementation

[0036] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Furthermore, unless otherwise specified, the above embodiments and features described herein can be combined with each other.

[0037] Existing biomass gasification technologies generally rely on traditional external heating methods, which suffer from slow heating rates (≤10℃ / s) and insufficient reaction temperatures (800-1200℃). This leads to incomplete biomass conversion, resulting not only in the production of large amounts of wood tar causing pipeline blockages, but also in the formation of syngas. The concentration is usually below 85%, and the product quality is difficult to meet the needs of industrial applications. At the same time, the solid by-products (crude carbon) generated in the gasification process are mostly low-value-added products with disordered pore structure and high impurity content, which cannot be used directly as high-end carbon materials, resulting in a waste of biomass resources.

[0038] Existing hard carbon preparation processes also face numerous bottlenecks: traditional pyrolysis processes require prolonged high-temperature treatment for several to tens of hours, consuming energy exceeding 80 kWh / kg; and the reliance on heat conduction for heating leads to uneven temperature field distribution, making it difficult to precisely control key parameters such as interlayer spacing and pore structure of hard carbon materials, often resulting in disordered pore size distribution and insufficient closed-pore ratio, causing the first-cycle reversible specific capacity to be generally below 300 mAh / g. Some processes require the introduction of chemical activators, dopants, and other additives to optimize performance, which not only increases production costs but may also cause environmental pollution. Furthermore, the heterogeneity of biomass raw material components further exacerbates the problem of poor batch stability of the product.

[0039] To address the aforementioned technical deficiencies, this invention proposes a two-step Joule heating synergistic control strategy. Through a continuous process of "transient high-temperature gasification pore-forming - precise carbonization pore sealing," it simultaneously achieves efficient co-production of hydrogen-rich syngas and high-performance hard carbon materials.

[0040] like Figure 1 As shown, an embodiment of the present invention provides a method for the transient high-temperature gasification of biomass to co-produce hydrogen-rich syngas and hard carbon materials, comprising the following steps:

[0041] S1: Preparation of conductive preform

[0042] Biomass raw materials, conductive additives, and water are mixed at a mass ratio of 10:(0.8-1.5):(2-4). The mixture is then placed in a ball mill and milled for 2-4 hours to form a uniform slurry. The slurry is then poured into a mold and pressed at 200-400 MPa for 10-20 seconds to produce a high-density conductive preform. The conductive additive is biochar or recycled carbon powder produced by the system. The resistivity of the conductive preform is reduced to a minimum. This meets the requirements for efficient conduction of Joule heating.

[0043] More specifically, in step S1, the biomass raw material is one or more of bamboo powder, sawdust, rice husks, or straw, and the original resistivity of the biomass raw material is higher than that of bamboo powder, sawdust, rice husks, or straw. .

[0044] S2: Primary Joule heating and vaporization

[0045] Place the conductive preform within the reaction chamber of the primary Joule-heated reactor, ensuring tight contact between both ends of the preform and the electrodes. Start the vacuum pump to reduce the absolute pressure in the reaction chamber to below 1000 Pa. Start the programmable DC power supply in constant current mode. A direct current is applied to the billet, causing it to rapidly heat up to [temperature value] within 1.0-2 seconds due to the Joule effect. The biomass is then maintained at this temperature for 3-7 seconds to complete the high-temperature gasification reaction. The generated hydrogen-rich syngas is collected through a gas collection and purification system, while the residual primary porous carbon in the reactor is also collected.

[0046] More specifically, in step S2, the absolute pressure of the vacuum environment is preferably 50-200 Pa; and the current for the first-stage Joule heating is preferably raised to a preset value within 0.5-1.0 seconds.

[0047] More specifically, in step S2, the preferred current density for the first-stage Joule heating is... The vaporization temperature is .

[0048] S3: Secondary billet preparation

[0049] Primary porous carbon and binder are mixed at a mass ratio of 10:(1.5-3) and placed in a ball mill jar for 1-2 hours to form a uniform slurry. The slurry is then poured into a mold and held under a set pressure for 10-15 seconds to produce a secondary green body.

[0050] More specifically, in step S3, the binder is wood tar or bio-oil; the slurry after mixing the primary porous carbon and the binder is ball-milled and then pressed into shape under a pressure of 150-300 MPa; the specific surface area of ​​the primary porous carbon is... After two-stage Joule heating, the specific surface area of ​​the hard carbon material decreased to [a value missing]. The interlayer spacing is 0.34-0.38 nm.

[0051] S4: Secondary Joule heating carbonization

[0052] The secondary preform is placed in the reaction chamber of the secondary Joule-heated reactor, and either a vacuum or a protective atmosphere can be introduced. The programmable DC power supply is then activated. A direct current is applied at a current density that raises the temperature of the secondary billet to [temperature value] within 1-3 seconds. The mixture is heated to a temperature of 10-30 seconds, and the open pores of the primary porous carbon are sealed by pyrolysis of carbon through a binder, thereby optimizing the microstructure of the hard carbon material. After the reaction is complete, the mixture is cooled to room temperature, and the hard carbon material is collected.

[0053] More specifically, in step S4, the protective atmosphere is nitrogen or argon; the heating rate of the secondary Joule heating is greater than 1000°C / s.

[0054] More specifically, in step S4, the preferred current density for the secondary Joule heating is... The carbonization temperature is 1180-1220℃.

[0055] More specifically, the yield of the hard carbon material is (Compared to the initial mixture of biomass and conductive additives), at a current density of 0.1C, the first-cycle reversible specific capacity is no less than .

[0056] More specifically, the total yield of the hydrogen-rich syngas is not less than 1200 mL / g biomass, of which the hydrogen yield is not less than 700 mL / g biomass, and the syngas contains... The sum of the volume concentrations of CO and CO is not less than 95%.

[0057] Please see Figure 3 As shown, this embodiment of the invention also provides a system for implementing the above-described method. The system includes a primary Joule heating reactor 10, a gas collection and purification system 20, a mixing and forming device 30, a secondary Joule heating reactor 40, and a solid collection device 50, wherein:

[0058] The primary Joule heating reactor 10 is used to realize the gasification reaction in step S2, and its outlet is connected to the gas collection and purification system 20 and the mixing and forming device 30 respectively.

[0059] The mixing and molding device 30 is used to complete the mixing and molding in step S3, and its outlet is connected to the secondary Joule heating reactor 40.

[0060] The secondary Joule heating reactor 40 is used to realize the carbonization reaction in step S4, and its outlet is connected to the solid collection device 50.

[0061] Both the primary Joule heating reactor 10 and the secondary Joule heating reactor 40 are equipped with a vacuum system and a programmable DC power supply.

[0062] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0063] In the embodiments, the gas yield was calculated by argon equilibrium method using internal standard argon gas combined with gas chromatography analysis of component volume concentration; the electrochemical performance of the hard carbon material was tested using a half-cell test with sodium sheet as positive electrode, and the test instrument was a LAND CT2001A tester; the microstructure of the material was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM); and the energy consumption was measured by a precision energy meter to measure the power consumption of the entire reaction process.

[0064] Example 1

[0065] Using bamboo powder as biomass raw material and self-produced recycled biochar as conductive additive, the specific steps are as follows:

[0066] S1: Weigh 100g of dried bamboo powder, 10g of biochar, and 30g of deionized water in a mass ratio of 10:1:3, and ball mill them in a mill jar for 3 hours to obtain a uniform slurry. Take 10g of the slurry and place it into a cylindrical mold with a diameter of 20mm. Press it under 300MPa pressure for 15 seconds to form a high-density conductive preform. The resistivity of this conductive preform was measured to be... .

[0067] S2: Place the conductive preform in the reaction chamber of the first-stage Joule heating reactor and connect the electrodes. Start the vacuum pump to evacuate the chamber to an absolute pressure of 100 Pa. Set the programmable DC power supply to constant current mode, according to... Current density (approximately [volume of billet]) The target current was set at 126A. Discharge was initiated, and the current reached 126A within 0.8 seconds and remained constant. The temperature of the green body reached 1350℃ after approximately 1.2 seconds. The total constant current discharge time was 5 seconds (including a 5-second holding time). After the reaction, the gaseous products were collected using a gas collection and purification system and analyzed by gas chromatography. Primary porous carbon within the reactor was also collected.

[0068] S3: Take the collected primary porous carbon and 20wt% wood tar (based on the mass of primary porous carbon), place them in a ball mill jar and ball mill for 1.5 hours to form a uniform mixed slurry. Take 5g of the mixed slurry and put it into a cylindrical mold with a diameter of 15mm, hold it under pressure of 200MPa for 10 seconds to make a secondary green body.

[0069] S4: Place the secondary preform in the reaction chamber of the secondary Joule heating reactor and evacuate to an absolute pressure of 100 Pa. Set the programmable DC power supply to constant current mode, according to... Current density (secondary billet volume approximately) The target current was set to 45A. Discharge was initiated, and the secondary preform heated to 1200°C in approximately 0.8 seconds and held at that temperature for 20 seconds. After the reaction was complete, it was cooled to room temperature, and the hard carbon material was collected.

[0070] Product Analysis:

[0071] Hydrogen-rich synthesis gas: The total volume of non-condensable gas in a single reaction is 9093 mL, and the yield is... Bamboo powder. The hydrogen volume was 5314 mL, and the yield was... Bamboo powder; CO volume was 3412 mL. The sum of the volume concentrations of CO and CO is 97%.

[0072] Hard carbon material: 1.4 g of hard carbon powder was obtained, with a yield of 14.0 wt% (relative to the initial mixed solid raw material of bamboo powder and biochar). As a sodium electrode anode, it exhibited a reversible specific capacity of 391 mAh / g in the first cycle at a current density of 0.1 C, and a capacity retention of 92% after 50 cycles.

[0073] Energy consumption calculation: The first-stage Joule heating and gasification consumes approximately 0.01428 kWh of electricity, and the second-stage Joule heating and carbonization consumes approximately 0.01002 kWh of electricity. When converted to the production of 1 kg of hard carbon material, the total electricity consumption for the entire process is approximately 17.4 kWh, and the co-production of hydrogen-rich syngas is approximately 9.09 cubic meters.

[0074] Example 2

[0075] Using pine sawdust as biomass raw material, and with other conditions the same as in Example 1, biochar was used as a conductive additive. However, the mass of the slurry used per application was increased to 20g, and a 30mm diameter mold was used for molding. The specific steps are as follows:

[0076] S1: Weigh 200g of dried pine sawdust, 24g of biochar, and 50g of deionized water in a mass ratio of 10:1.2:2.5, and ball mill them in a mill jar for 3.5 hours to obtain a homogeneous slurry. Take 20g of the slurry and place it into a cylindrical mold with a diameter of 30mm. Press it under 350MPa pressure for 12 seconds to form a high-density conductive preform. The resistivity of this conductive preform was measured to be... .

[0077] S2: Place the conductive preform in the reaction chamber of the first-stage Joule heating reactor and connect the electrodes. Start the vacuum pump to evacuate the chamber to an absolute pressure of 150 Pa. Set the programmable DC power supply to constant current mode, according to... Current density (approximately [volume of billet]) The target current was set at 235.6 A. Discharge was initiated, and the current reached 235.6 A within 0.9 seconds and remained constant. The temperature of the billet reached 1300°C after approximately 1.4 seconds. The total constant current discharge time was 6 seconds (including a 5-second holding time). After the reaction was completed, the hydrogen-rich synthesis gas and primary porous carbon were collected.

[0078] S3: Take the collected primary porous carbon and 25wt% bio-oil (based on the mass of primary porous carbon), place them in a ball mill jar and ball mill for 1.2 hours to form a uniform mixed slurry. Take 10g of the mixed slurry and put it into a cylindrical mold with a diameter of 20mm, hold it under pressure of 250MPa for 12 seconds to make a secondary green body.

[0079] S4: Place the secondary preform in the reaction chamber of the secondary Joule heating reactor, and introduce argon gas as a protective atmosphere (purity ≥ 99.99%). Set the programmable DC power supply to constant current mode, according to... Current density (secondary billet volume approximately) The target current was set to 96A. Discharge was initiated, and the secondary preform heated to 1190°C in approximately 1.0 second and held at that temperature for 25 seconds. After the reaction was complete, it was cooled to room temperature, and the hard carbon material was collected.

[0080] Product Analysis:

[0081] Hydrogen-rich syngas: Total yield Wood chips, hydrogen yield Wood chips, The sum of the volume concentrations of CO and CO is 96.5%.

[0082] Hard carbon material: yield approximately 13.8 wt%, reversible specific capacity of 378 mAh / g in the first cycle at a current density of 0.1C, and capacity retention of 90% after 50 cycles.

[0083] Energy consumption calculation: The total power consumption for the entire process is approximately 18.1 kWh / kg of hard carbon material.

[0084] Figure 2 The figure shows the electrochemical cycling performance of the hard carbon materials prepared by Examples 1 and 2 above. The "0.1C, 0.2C...6C" on the curves represent different current densities (i.e., charge and discharge rates). The larger the value, the faster the charge and discharge speed. Figure 2 This demonstrates how the specific capacity of the hard carbon material prepared in this invention changes with the number of cycles at different charge and discharge rates: even at higher current densities (such as 6C), the material can still maintain a high specific capacity, and the capacity decays slowly after multiple cycles, indicating that it has both excellent rate performance and cycle stability.

[0085] Comparative Example 1

[0086] The specific steps for preparing hard carbon materials using a traditional slow pyrolysis process are as follows:

[0087] Take 100g of bamboo powder, the same as in Example 1, and purge it in a tube furnace with nitrogen as a protective atmosphere. Heat the furnace to 1200°C at a rate of 5°C / min and hold for 2 hours for pyrolysis and carbonization. After cooling to room temperature, collect the carbon material and perform electrochemical performance tests.

[0088] Results: The first-cycle reversible specific capacity of the obtained carbon material was 265 mAh / g, the total gas yield was only 280 mL / g, the hydrogen yield was 85 mL / g, and the total power consumption was about 85 kWh / kg of carbon material. The energy consumption was much higher than that of the method of this invention, and the product performance and resource utilization efficiency were significantly lower than those of this invention.

[0089] Comparative Example 2

[0090] Hard carbon materials are prepared using a single Joule heating process without co-producing hydrogen-rich syngas. The specific steps are as follows:

[0091] Take the same bamboo powder (100g), biochar (10g), and deionized water (30g) as in Example 1, and prepare a conductive preform according to step S1 of Example 1. Place the conductive preform in a Joule-heated reactor, to... The carbon material was heated to 1200℃ using a high current density and held for 30 minutes. After cooling, the carbon material was collected.

[0092] Results: The first-cycle reversible specific capacity of the obtained carbon material was 310 mAh / g. The gaseous products were directly emitted without collection, resulting in serious resource waste. Furthermore, the long heat preservation time led to energy consumption as high as 42 kWh / kg of carbon material, making it far less economical than the present invention.

[0093] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the scope of protection of this invention.

Claims

1. A method for the transient high-temperature gasification of biomass to co-produce hydrogen-rich syngas and hard carbon materials, characterized in that, Includes the following steps: S1: By mass ratio Biomass raw materials, conductive additives, and water are mixed and then ball-milled into a slurry. The conductive blank is formed by pressing under pressure. S2: Place the conductive blank in a vacuum environment with an absolute pressure lower than 1000 Pa, so as to A direct current is applied at a certain current density to perform first-stage Joule heating, which raises the temperature of the conductive blank to 1100-1500℃ within 1.0-2 seconds and maintains it for 3-7 seconds, thus completing the biomass gasification. S3: Collect the hydrogen-rich synthesis gas and primary porous carbon produced in step S2, mix the primary porous carbon and binder at a mass ratio of 10:(1.5-3), ball mill and form to obtain a secondary green body; S4: Place the secondary preform in a protective atmosphere or vacuum environment, so as to A direct current is applied at a certain current density to perform secondary Joule heating, which raises the temperature of the secondary blank to 1150-1250℃ within 1-3 seconds and holds it at that temperature for 10-30 seconds to obtain hard carbon material.

2. The method according to claim 1, characterized in that, In step S1, the conductive additive is biochar or recycled carbon powder produced by the system; the resistivity of the conductive blank is .

3. The method according to claim 1, characterized in that, In step S1, the biomass raw material is one or more of bamboo powder, sawdust, rice husk, or straw, and the original resistivity of the biomass raw material is higher than that of bamboo powder, sawdust, rice husk, or straw. .

4. The method according to claim 1, characterized in that, In step S2, the absolute pressure of the vacuum environment is 50-200 Pa; the current for the first-stage Joule heating rises to a preset value within 0.5-1.0 seconds.

5. The method according to claim 1, characterized in that, In step S3, the binder is wood tar or bio-oil; the slurry after mixing the primary porous carbon and the binder is ball-milled and then pressed into shape under a pressure of 150-300 MPa; the specific surface area of ​​the primary porous carbon is... ; After two-stage Joule heating, the specific surface area of ​​the hard carbon material decreased to The interlayer spacing is 0.34-0.38 nm.

6. The method according to claim 1, characterized in that, In step S4, the protective atmosphere is nitrogen or argon; the heating rate of the secondary Joule heating is greater than... .

7. The method according to any one of claims 1-6, characterized in that, The yield of the hard carbon material is 13-15 wt%, and the first-cycle reversible specific capacity is not less than 370 mAh / g at a current density of 0.1C.

8. The method according to any one of claims 1-6, characterized in that, The total yield of the hydrogen-rich syngas is not less than 1200 mL / g, of which the hydrogen yield is not less than 700 mL / g, and the syngas contains... The sum of the volume concentrations of CO and CO is not less than 95%.

9. The method according to claim 1, characterized in that, In step S2, the current density of the first-stage Joule heating is The vaporization temperature is ; In step S4, the current density of the secondary Joule heating is The carbonization temperature is 1180-1220℃.

10. A system for implementing the method according to any one of claims 1-9, characterized in that, It includes a primary Joule heating reactor, a gas collection and purification system, a mixing and molding device, a secondary Joule heating reactor, and a solid collection device; The primary Joule heating reactor is used to realize the gasification reaction in step S2, and its outlet is connected to the gas collection and purification system and the mixing and forming device, respectively. The mixing and molding device is used to complete the mixing and molding in step S3, and its outlet is connected to a secondary Joule heating reactor. The secondary Joule heating reactor is used to realize the carbonization reaction in step S4, and its outlet is connected to a solid collection device. Both the primary Joule heating reactor and the secondary Joule heating reactor are equipped with a vacuum system and a programmable DC power supply.

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