Method and device for preparing hydrogen-rich methane gas from kitchen garbage through hydrothermal cascade

Abstract

The invention relates to the technical field of solid waste energy utilization, and discloses a method and device for preparing hydrogen-rich methane gas through kitchen garbage hydrothermal cascade. According to the method, through the steps of mechanical crushing, pH adjustment, low-temperature hydrothermal homogeneous classification, three-phase separation, graded high-temperature hydrothermal gasification, gas separation and purification, resource recycling and the like, the technical bottlenecks of large mass transfer resistance and low gasification efficiency during traditional hydrothermal gasification treatment of the wet-based biomass with the high solid content are solved. The corresponding device comprises a crushing unit, a pretreatment unit, a low-temperature hydrothermal unit, a separation unit, a high-temperature gasification unit, a gas purification unit, a heat recovery unit and a cyclic utilization unit, all the units cooperate to realize efficient conversion of kitchen garbage into hydrogen-rich methane gas, carbon dioxide is recovered to prepare dry ice, wastewater is recycled, and a catalyst is recycled and regenerated. And the energy conversion efficiency and the resource utilization rate are obviously improved.

Description

Technical Field

[0001] This invention relates to the field of energy utilization technology of solid waste, specifically to a method and apparatus for preparing hydrogen-rich methane gas from kitchen waste via hydrothermal cascade. Background Technology

[0002] Addressing climate change and promoting energy transition have become a global consensus, and reducing carbon emissions and developing clean energy are key pathways to achieving carbon neutrality. Food waste, a major form of urban solid waste, originates from home cooking, the catering industry, and agricultural wholesale markets. It includes vegetable leaves, leftover food, fruit peels, eggshells, etc., and is characterized by high moisture content, high organic matter content, easy decomposition and odor, and easy biodegradability. Since my country implemented its household waste sorting system, the amount of food waste has surged, and is projected to reach 120 million tons by 2025. Improper disposal not only occupies land resources but also pollutes the environment and generates large amounts of greenhouse gases. Therefore, converting food waste into high-value clean energy has become an urgent need.

[0003] Hydrothermal gasification is a promising biomass energy conversion technology that can convert organic matter in wet biomass into hydrogen-rich methane gas. However, traditional hydrothermal gasification technology is only suitable for kitchen waste with low solids content. When processing materials with high solids content, it faces technical bottlenecks such as high mass transfer resistance and low gasification efficiency. The fundamental reason is that during the hydrothermal gasification of high-solids wet biomass, small-molecule, easily gasifiable organic components preferentially compete for water molecules for rapid gasification, resulting in large-molecule, difficult-to-gasify organic components not receiving enough water molecules to attack them, thus inhibiting the overall gasification efficiency.

[0004] To address the aforementioned issues, this invention proposes a method and apparatus for the hydrothermal cascade preparation of hydrogen-rich methane gas. By using low-temperature hydrothermal processes to achieve homogeneous classification of organic components, followed by staged high-temperature hydrothermal gasification, the invention ensures that both types of components can be efficiently converted, providing technical support for the clean energy utilization of kitchen waste and wet sludge. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for preparing hydrogen-rich methane gas from kitchen waste via hydrothermal cascade.

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

[0007] S1. Raw material pretreatment: Wet biomass such as kitchen waste and wet sludge is fed into a mechanical crusher and crushed into a uniform slurry. The pH of the slurry is adjusted to 1~13 by adding 5.0M sodium hydroxide solution or 36% hydrochloric acid to meet the requirements of subsequent hydrothermal reaction.

[0008] S2. Low-Temperature Hydrothermal Homogeneous Classification: After pH adjustment, the slurry is preheated in the first preheater and then fed into a low-temperature hydrothermal reactor, where the temperature is raised to 120-240℃ and maintained for 180-480 minutes. This process enables the easily gasifiable small-molecule organic components and the difficult-to-gasify large-molecule organic components in the slurry to achieve homogeneous classification in terms of physical and chemical properties, laying the foundation for subsequent staged gasification.

[0009] S3, Three-phase separation: The low-temperature hydrothermal reaction products enter the three-phase separator to achieve gas-liquid-solid three-phase separation: the liquid product is discharged from the first outlet at the bottom; the solid product is discharged from the second outlet at the top; and the gaseous product is discharged from the third outlet on the upper left side.

[0010] S4, Staged High-Temperature Hydrothermal Gasification:

[0011] The liquid product is preheated by the second preheater and pressurized by the first high-pressure pump before entering the first high-temperature hydrothermal gasification reactor. It is fully mixed with a porous nickel-based catalyst at a ratio of 1.2 g / g TOC and reacted at 450°C for 30 min, where the easily gasifiable organic components are efficiently converted into hydrogen-rich methane gas.

[0012] The solid product is fed into the stirrer, and the wastewater discharged from the first high-temperature hydrothermal gasification reactor and cooled by the heat exchanger is also fed into the stirrer to mix with the solid product to form a slurry with a solid content of 10% to 30%. The slurry is preheated by the third preheater and pressurized by the second high-pressure pump before entering the second high-temperature hydrothermal gasification reactor, where it is mixed with a porous nickel-based catalyst at a ratio of 1.2 g / g TOC and reacted at 450°C for 30 min. The difficult-to-gasify organic components are efficiently gasified with a sufficient supply of water molecules.

[0013] S5. Gas treatment and purification: The products of the two high-temperature hydrothermal gasification reactors are cooled to below 100°C by the first heat exchanger. The gas products are then depressurized by the first and second pressure reducing valves and fed into the gas membrane separation unit to separate hydrogen-rich methane and carbon dioxide. The hydrogen-rich methane is stored in a gas holder for temporary storage, and the carbon dioxide is sent to the dry ice manufacturing unit to prepare dry ice, thus realizing carbon resource recovery.

[0014] S6. Resource recycling and waste heat utilization:

[0015] The high-temperature heat recovered by the first heat exchanger provides a heat source for the second and third preheaters. The combustion heat from the second heat exchanger and the combustion chamber heats the first preheater and the drying chamber, thus achieving energy cascade utilization.

[0016] The solid-liquid mixture discharged from the second high-temperature hydrothermal gasification reactor is separated by a solid-liquid separator. The solid product is sent to the drying chamber for drying and then the porous nickel-based catalyst is recovered through the catalyst magnetic recovery unit. The remaining residue is sent to the combustion chamber for incineration. The liquid product is sent to the wastewater treatment plant for treatment and, after meeting the standards, is used as circulating water or system makeup water.

[0017] The gaseous products separated by the three-phase separator are directly sent to the combustion chamber for incineration to supplement the heat supply.

[0018] Device technical solution

[0019] The device of the present invention is a hardware implementation of the above method, with each unit working together in coordination. The specific structure is as follows:

[0020] 1. Crushing Unit: Mechanical crusher, used to crush lumpy wet biomass into a uniform slurry to ensure uniform mass transfer in subsequent reactions.

[0021] 2. Pretreatment unit: includes an acid-base addition device and a first preheater. The acid-base addition device is used to precisely adjust the pH of the slurry, and the first preheater is used to preheat the slurry to reduce the energy consumption of the low-temperature hydrothermal reactor.

[0022] 3. Low-temperature hydrothermal unit: The low-temperature hydrothermal reactor adopts a jacketed heating structure, which can precisely control the reaction temperature of 120-240℃ and the reaction time of 180-480min, so as to achieve homogeneous classification of organic components.

[0023] 4. Separation Unit:

[0024] Three-phase separator: It adopts a gravity-centrifugal composite separation structure with a separation efficiency of ≥95% and has three outlets corresponding to the discharge of gaseous, liquid and solid products respectively.

[0025] Solid-liquid separator: It adopts a filter-type separation structure to separate the solid-liquid mixture discharged from the second high-temperature hydrothermal gasification reactor, with a separation accuracy of ≥10μm.

[0026] 5. High-temperature gasification unit:

[0027] The first high-temperature hydrothermal gasification reactor and the second high-temperature hydrothermal gasification reactor are both high-pressure reactors with a design pressure ≥10MPa. They adopt electric heating or waste heat heating methods and can stably control the reaction temperature to 450℃.

[0028] Agitator: Used to mix solid products with wastewater to form a uniform slurry, ensuring the uniformity of subsequent gasification reactions.

[0029] First high-pressure pump and second high-pressure pump: designed pressure ≥15MPa, used to send the preheated slurry / liquid into the high-temperature hydrothermal gasification reactor under high pressure.

[0030] Second and third preheaters: They use the heat recovered from the heat exchanger to preheat the materials, reducing system energy consumption.

[0031] 6. Gas processing unit:

[0032] First pressure reducing valve and second pressure reducing valve: used to reduce the pressure of high-temperature gasification products and adapt to the working pressure of the gas membrane separation unit.

[0033] Gas membrane separation unit: adopts polyimide composite membrane, with hydrogen-rich methane gas purity ≥90% and carbon dioxide separation efficiency ≥95%.

[0034] Dry ice manufacturing unit: The separated carbon dioxide is made into dry ice, realizing the recycling of carbon resources.

[0035] 7. Heat recovery unit:

[0036] First heat exchanger: shell and tube structure, recovers heat from high-temperature gasification products, with a heat recovery efficiency of ≥85%, and provides heat for the second and third preheaters.

[0037] The second heat exchanger recovers the combustion heat from the combustion chamber with a heat recovery efficiency of ≥80%, providing heat for the first preheater and the drying chamber.

[0038] 8. Resource recycling unit:

[0039] Drying chamber: Uses hot air drying at a temperature of 100~120℃ to dry solid products, facilitating catalyst recovery.

[0040] Catalyst magnetic recovery unit: Adopts high-intensity magnetic separation structure, catalyst recovery rate ≥90%, reducing operating costs.

[0041] Combustion chamber: Employs pulse combustion technology with an incineration temperature ≥850℃ to ensure harmless treatment of residues while recovering heat.

[0042] Wastewater treatment plant: adopts "anaerobic + aerobic" treatment process, the COD of the treated wastewater is ≤50mg / L, and it can be recycled.

[0043] The beneficial effects of this invention are as follows:

[0044] This invention solves the core problems of high mass transfer resistance and low gasification efficiency in traditional hydrothermal gasification for treating high-solids-content wet-based biomass by employing a cascade process of "low-temperature hydrothermal homogeneous classification + staged high-temperature hydrothermal gasification." The low-temperature hydrothermal stage achieves precise classification of easily gasifiable and difficult-to-gasify organic components, while staged gasification ensures sufficient reaction conditions for both types of components, significantly improving the yield and quality of hydrogen-rich methane gas. Example data shows that when treating kitchen waste, the molar yield of hydrogen-rich methane gas is increased by more than 10.92% compared to traditional technologies, with a maximum increase of 131.44% in CH4 content and more than 69.18% in calorific value; when treating wet sludge, the yield is increased by 66.99%, and the product quality is significantly optimized, providing an efficient technical path for the energy utilization of high-solids-content wet-based biomass.

[0045] This invention constructs a full-process resource recycling and waste heat cascade utilization system, achieving a highly efficient closed loop of energy and matter. The heat recovery unit recovers heat from high-temperature gasification products and incineration through heat exchangers for preheating in various stages, achieving a heat recovery efficiency of up to 85%, significantly reducing system energy consumption; the catalyst achieves a recovery rate of over 90% through a magnetic recovery unit, allowing for recycling and reducing operating costs; wastewater, after "anaerobic + aerobic" treatment, has a COD ≤ 50 mg / L and can be recycled for water replenishment, reducing water resource consumption; carbon dioxide is recovered to produce dry ice, realizing carbon resource utilization, avoiding greenhouse gas emissions, and achieving both environmental and economic benefits.

[0046] This invention is not only applicable to kitchen waste, but also efficiently treats various wet-based biomass such as wet sludge, adapting to the processing needs of materials with different solid contents of 10%~30%, thus solving the problem of the narrow applicability of traditional technologies. The various units of the device are rationally designed for collaboration. The low-temperature hydrothermal reactor can precisely control the temperature (120~240℃) and time (180~480min), while the high-temperature gasification reactor adopts a high-pressure reactor structure. Combined with a catalyst mixing structure, this ensures uniform and stable reaction. The separation unit has a separation efficiency of ≥95%. The overall device operates stably and reliably, making it easy to promote and apply industrially.

[0047] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the structure of the device of the present invention;

[0049] Reference numerals: 1. Mechanical pulverizer; 2. First preheater; 3. Low-temperature hydrothermal reactor; 4. Three-phase separator; 5. Second preheater; 6. First high-pressure pump; 7. First high-temperature hydrothermal gasification reactor; 8. Pressure reducing valve; 9. First heat exchanger; 10. Stirrer; 11. Second preheater; 12. Second high-pressure pump; 13. Second high-temperature hydrothermal gasification reactor; 14. Pressure reducing valve; 15. Solid-liquid separator; 16. Wastewater treatment station; 17. Drying chamber; 18. Catalyst magnetic recovery unit; 19. Combustion chamber; 20. Second heat exchanger; 21. Gas membrane separation unit; 22. Dry ice manufacturing unit. Detailed Implementation

[0050] The following combination Figure 1 The technical effects of the present invention are verified through specific embodiments. Process parameters not specified in the embodiments are all performed in accordance with the above technical solution.

[0051] Example 1: Traditional high-temperature hydrothermal gasification (kitchen waste)

[0052] The pH of wet kitchen waste with a solids content of 20% was adjusted to 5.0, and a porous nickel-based catalyst was added at 1.2 g / g TOC. The reaction was carried out at 450℃ for 30 min. Results: The molar yield of hydrogen-rich methane gas was 23.27 mol / kg dry basis, the H2 content was 29.08%, the CH4 content was 17.46%, the calorific value was 251.08 kJ / mol, and 1 kg of dry basis kitchen waste produced 5842.80 kJ of clean energy.

[0053] Example 2: Low-temperature hydrothermal treatment + single high-temperature gasification (kitchen waste)

[0054] Wet kitchen waste with a solids content of 20% was adjusted to pH 5.0 and subjected to a low-temperature hydrothermal reaction at 240℃ for 240 min. The product was then mixed with a catalyst and gasified at 450℃ for 30 min. Results: The molar yield of hydrogen-rich methane was 22.74 mol / kg dry basis, with an H2 content of 26.91%, a CH4 content of 25.86%, and a calorific value of 308.82 kJ / mol. 1 kg dry basis produced 7021.70 kJ of clean energy, which is 20.18% higher than that of Example 1.

[0055] Example 3: Hydrothermal Cascade Gasification (Kitchen Waste, Slurry Solids Content 20%)

[0056] Wet kitchen waste with a solids content of 20% was adjusted to pH 5.0, subjected to hydrothermal treatment at 240℃ for 240 min, and after three-phase separation, the liquid product was vaporized separately, while the solid product was mixed with wastewater and then vaporized. The solids content was 20%. Results: The molar yield of hydrogen-rich methane gas was 25.81 mol / kg dry basis, which was 10.92% higher than that of Example 1 and 13.53% higher than that of Example 2; the CH4 content was 44.40%, which was 131.44% higher than that of Example 1 and 56.23% higher than that of Example 2; the calorific value was 427.74 kJ / mol, which was 69.18% higher than that of Example 1 and 37.55% higher than that of Example 2; and 10965.55 kJ of clean energy was produced per kg dry basis, which was 87.68% higher than that of Example 1 and 56.17% higher than that of Example 2.

[0057] Example 4: Hydrothermal Cascade Gasification (Kitchen Waste, Slurry Solids Content 10%)

[0058] The process was the same as in Example 3, except that the solid content of the slurry after mixing the solid product with the wastewater was 10%. Results: The molar yield of hydrogen-rich methane was 30.03 mol / kg dry basis, which was 16.31% higher than that in Example 3; the H2 content was 34.05%, which was 52.71% higher than that in Example 3; the calorific value was 397.13 kJ / mol; and 1 kg dry basis produced 11924.07 kJ of clean energy, which was 8.74% higher than that in Example 3, showing high selectivity for hydrogen.

[0059] Example 5: Hydrothermal Cascade Gasification (Kitchen Waste, Slurry Solids Content 30%)

[0060] The process was the same as in Example 3, except that the solid content of the slurry after mixing the solid product with the wastewater was 30%. Results: The molar yield of hydrogen-rich methane was 24.36 mol / kg dry basis, the CH4 content was 43.57%, which was 29.88% higher than that in Example 4, and the calorific value was 441.13 kJ / mol, which was 11.08% higher than that in Example 4, showing high selectivity for methane.

[0061] Example 6: Traditional high-temperature hydrothermal gasification (wet sludge)

[0062] Wet sludge with a solids content of 20% was adjusted to pH 6.0, and a catalyst was added at 1.2 g / g TOC. The mixture was then gasified at 450℃ for 30 min. Results: The molar yield of hydrogen-rich methane was 9.89 mol / kg dry basis, with H2 content of 44.04%, CH4 content of 11.70%, and a calorific value of 234.77 kJ / mol. 2321.83 kJ of clean energy was produced per kg dry basis.

[0063] Example 7: Hydrothermal Cascade Gasification (Wet Sludge)

[0064] Wet sludge with a solids content of 20% was adjusted to pH 6.0, subjected to low-temperature hydrothermal treatment at 240℃ for 240 min, and then subjected to three-phase separation followed by staged gasification. Results: The molar yield of hydrogen-rich methane was 16.52 mol / kg dry basis, which was 66.99% higher than that of Example 6; the CH4 content was 16.11%, which was 37.67% higher than that of Example 6; and the calorific value was 284.54 kJ / mol, which was 21.60% higher than that of Example 6, significantly improving the quality of sludge gasification products.

[0065] The above embodiments demonstrate that, compared with traditional hydrothermal gasification technology, the hydrothermal cascade method and apparatus of the present invention can significantly improve the yield, calorific value, and target component H2 or CH4 content of hydrogen-rich methane gas, while realizing energy cascade utilization, catalyst recovery, wastewater recycling, and carbon resource recovery. It is suitable for the clean energy treatment of various wet-based biomass such as kitchen waste and wet sludge, and has significant technical advantages and application prospects.

[0066] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0067] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing hydrogen-rich methane gas from kitchen waste via hydrothermal cascade, characterized in that, Includes the following steps: S1. Raw material pretreatment: Wet biomass such as kitchen waste or wet sludge is mechanically crushed into slurry, and 5.0M sodium hydroxide solution or 36% hydrochloric acid is added to adjust the pH of the slurry to 1-13; S2. Low-temperature hydrothermal homogeneous classification: After pH adjustment, the slurry is preheated and then fed into a low-temperature hydrothermal reactor. It is reacted at 120-240℃ for 180-480 min to achieve homogeneous classification of easily gasifiable small-molecule organic components and difficult-to-gasify large-molecule organic components. S3, Three-phase separation: The low-temperature hydrothermal reaction products are passed into a three-phase separator to separate liquid products, solid products and gaseous products; S4. Staged high-temperature hydrothermal gasification: The liquid product is preheated and transported under high pressure before entering the first high-temperature hydrothermal gasification reactor, where it is mixed with a porous nickel-based catalyst at a ratio of 1.2 g / g TOC and reacted at 450°C for 30 min to carry out high-temperature hydrothermal gasification. The solid product enters the stirrer and mixes with the cooled wastewater discharged from the first high-temperature hydrothermal gasification reactor to form a slurry. After preheating and high-pressure conveying, it enters the second high-temperature hydrothermal gasification reactor and is mixed with a porous nickel-based catalyst at a ratio of 1.2 g / g TOC. The mixture is then reacted at 450°C for 30 min to carry out high-temperature hydrothermal gasification. S5. Gas processing: The products of the two high-temperature hydrothermal gasification reactors are cooled to below 100°C and then introduced into the gas membrane separation unit after depressurization to separate hydrogen-rich methane gas and carbon dioxide. The hydrogen-rich methane gas is stored in the gas holder and the carbon dioxide is sent to the dry ice manufacturing unit to prepare dry ice. S6, Resource Cycling: The heat generated during the high-temperature hydrothermal gasification process is recovered by a heat exchanger to provide heat for each preheater and drying chamber. After separation, the solid-liquid mixture discharged from the second high-temperature hydrothermal gasification reactor is dried and the catalyst is recovered. The remaining residue is sent to the combustion chamber for incineration, and the heat from incineration is recovered and utilized. The wastewater generated during separation is treated and then used as recycled water or system makeup water. The gaseous products separated by the three-phase separator are directly sent to the combustion chamber for incineration to supplement the heat supply.

2. The method according to claim 1, characterized in that, The solids content of the slurry in step S4 is 10% to 30%.

3. The method according to claim 1, characterized in that, The porous nickel-based catalyst is recycled and reused after being recovered by a magnetic recovery unit.

4. An apparatus for implementing the method according to any one of claims 1 to 3, characterized in that, include: S1, Crushing Unit: is a mechanical crusher (1), used to crush wet biomass into slurry; S2, Pretreatment unit: includes an acid-base addition device for adjusting the pH of the slurry, and a first preheater (2), the first preheater (2) being used to preheat the pH-adjusted slurry; S3, Low-temperature hydrothermal unit: is a low-temperature hydrothermal reactor (3), connected to the outlet of the first preheater (2), used to realize the homogeneous classification of organic components; S4, Separation Unit: Includes a three-phase separator (4) and a solid-liquid separator (15). The three-phase separator (4) has three outlets, which correspond to the discharge channels of liquid products, solid products and gas products respectively. The solid-liquid separator (15) is used to separate the solid-liquid mixture discharged from the second high-temperature hydrothermal gasification reactor (13). S5, High-temperature gasification unit: including a first high-temperature hydrothermal gasification reactor (7), a second high-temperature hydrothermal gasification reactor (13), a stirrer (10), a first high-pressure pump (6), a second high-pressure pump (12), a second preheater (5), and a third preheater (11). The second preheater (5) is connected to the liquid product outlet of the three-phase separator (4) and is connected to the first high-temperature hydrothermal gasification reactor (7) via the high-pressure pump (6). The stirrer (10) is connected to the solid product outlet of the three-phase separator (4) and the wastewater outlet of the first heat exchanger (9) respectively, and is connected to the second high-temperature hydrothermal gasification reactor (13) via the third preheater (11) and the high-pressure pump (12). S6. Gas processing unit: including first pressure reducing valve (8), second pressure reducing valve (14), gas membrane separation unit (21), gas holder, dry ice manufacturing unit (22). The first pressure reducing valve (8) and the second pressure reducing valve (14) are respectively connected to the outlets of the first high temperature hydrothermal gasification reactor (7) and the second high temperature hydrothermal gasification reactor (13). The gas membrane separation unit (21) is connected to the outlet of the pressure reducing valve. The gas holder is connected to the hydrogen-rich methane gas outlet of the gas membrane separation unit (21). The dry ice manufacturing unit (22) is connected to the carbon dioxide outlet of the gas membrane separation unit (21). S7, Heat recovery unit: including a first heat exchanger (9) and a second heat exchanger (20). The first heat exchanger (9) is connected to the outlets of two high-temperature hydrothermal gasification reactors to cool the products and recover heat to supply heat to the second preheater (5) and the third preheater (11). The heat exchanger (20) is connected to the combustion chamber (19) to recover combustion heat to supply heat to the first preheater (2) and the drying chamber (17). S8, Resource Recycling Unit: Includes a catalyst magnetic recovery unit (18), a drying chamber (17), a combustion chamber (19), and a wastewater treatment station (16). The drying chamber (17) is connected to the solid product outlet of the solid-liquid separator (15). The catalyst magnetic recovery unit (18) is located between the drying chamber (17) and the combustion chamber (19). The wastewater treatment station (16) is connected to the wastewater outlet of the solid-liquid separator (15) for recycling water after treatment. The combustion chamber (19) is connected to the gas product outlet of the three-phase separator (4) and the outlet of the catalyst magnetic recovery unit (18) for incinerating gas and residue.

5. The apparatus according to claim 4, characterized in that, Both the first high-temperature hydrothermal gasification reactor (7) and the second high-temperature hydrothermal gasification reactor (13) are equipped with catalyst mixing structures to ensure that the slurry is in full contact with the porous nickel-based catalyst.

6. The apparatus according to claim 4, characterized in that, The heat exchanger (9) is a shell-and-tube heat exchanger. The first preheater (2), the second preheater (5), and the third preheater (11) are all shell-and-tube preheaters, and heat transfer is achieved through heat transfer oil or steam.

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