Supercritical water liquefaction-gasification multi-energy fusion treatment system and method for household garbage

Abstract

The invention relates to the technical field of waste resource utilization, and discloses a household garbage supercritical water liquefaction-gasification multi-energy fusion treatment system and method. The system comprises a household garbage primary treatment unit, a supercritical water liquefaction reactor unit, a supercritical water gasification reactor unit, a multi-stage oxidation reactor treatment unit, a liquid oxygen output pipeline, a steam reheat cycle power generation unit, a gas-liquid separator unit, a first turbine and a water tank. By means of the supercritical water liquefaction and gasification technology, efficient conversion of the household garbage is achieved, the household garbage is liquefied or gasified in the supercritical water environment, energy and substances in the household garbage are released, and the utilization efficiency of resources is improved. Through the multi-stage oxidation reactor treatment unit and the first turbine, generated heat energy is used for supplying heat, and gradient utilization and recycling of energy are achieved. Liquid oxygen used in the system reacts with mixed gas in the multi-stage oxidation reactor, so that emission of harmful substances can be reduced, and the environmental protection performance of the system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of waste resource utilization, and specifically to a system and method for treating domestic waste by supercritical water liquefaction-gasification multi-energy fusion. Background Art

[0002] Domestic waste refers to the various wastes generated in daily life, including but not limited to household waste, commercial waste, construction waste, cleaning waste, and garbage from public places. With rapid urbanization, industrialization, and population growth, the management of domestic waste has become a significant global challenge. Domestic waste primarily includes food waste, plastic waste, textile waste, and other materials. These materials have complex composition, high water and ash content, and low calorific value. Traditionally, domestic waste is disposed of in a variety of ways, including landfill, incineration, and composting.

[0003] While landfill technology is mature and simple to operate and manage, it occupies significant land resources, requires long processing times, and can easily cause soil and groundwater contamination. Fermentation also produces explosive gases, such as methane, which increases fire and explosion risks. Incineration is effective in reducing waste volume, but requires significant investment and a long capital investment cycle. It also requires a certain calorific value for the waste. Incineration can produce harmful gases, such as dioxins, which can accelerate global warming. Composting is a mature technology, but its efficiency is low, the processing cycle is long, and it can only process biodegradable waste. The compost product is not highly effective, and product quality cannot be guaranteed. Residual heavy metals in the compost can cause secondary pollution. Due to the profound impact of domestic waste on public health, environmental sustainability, and urban planning, waste disposal has received widespread attention in academic research and policy discussions in recent years, with increasing emphasis on its effective treatment. Summary of the Invention

[0004] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide a multi-energy fusion treatment system and method for supercritical water liquefaction-gasification of domestic waste, so as to solve the technical problem of how to improve the effective utilization of domestic waste resources in the prior art.

[0005] The present invention is achieved through the following technical solutions: In a first aspect, the present invention provides a multi-energy fusion treatment system for supercritical water liquefaction and gasification of domestic waste, comprising a domestic waste preliminary treatment unit, a supercritical water liquefaction reactor unit, a supercritical water gasification reactor unit, a multi-stage oxidation reactor treatment unit, a liquid oxygen output pipeline, a steam reheat cycle power generation unit, a gas-liquid separator unit, a first turbine, and a water tank; The output end of the water tank is provided with a first water flow pipeline, a second water flow pipeline and a third water flow pipeline; the first water flow pipeline is connected to the input end of the supercritical water gasification reactor unit; the second water flow pipeline is connected to the input end of the supercritical water gasification reactor unit through the supercritical water liquefaction reactor unit; the third water flow pipeline is connected to the input end of the supercritical water gasification reactor unit after passing through the domestic waste preliminary treatment unit and the supercritical water liquefaction reactor unit in sequence; The supercritical water gasification reactor unit is used to separate hydrogen from the mixed gas, wherein the output end of the mixed gas is connected to the input end of the multi-stage oxidation reactor processing unit; the output end of the multi-stage oxidation reactor processing unit is connected to the gas-liquid separator unit after passing through the first water flow pipeline, the second water flow pipeline and the third water flow pipeline in sequence, and is used to preheat the first water flow pipeline, the second water flow pipeline and the third water flow pipeline, and the output end of the gas-liquid separator unit is connected to the water tank; The output end of the liquid oxygen output pipeline is connected to the liquid oxygen input end of the multi-stage oxidation reactor processing unit; The working medium output end of the steam reheat cycle power generation unit is connected to the first turbine through the multi-stage oxidation reactor processing unit, and is used to supply heat to the outside or form a working medium heat circulation loop after passing through the first turbine.

[0006] Preferably, the first water flow pipeline is provided with a first water pump and a third heat exchanger in sequence along the water flow direction; the second water flow pipeline is provided with a second water pump and a second heat exchanger in sequence along the water flow direction; the third water flow pipeline is provided with a third water pump and a first heat exchanger in sequence along the water flow direction; The output end of the multi-stage oxidation reactor treatment unit is provided with a first cooler after passing through the third heat exchanger, the second heat exchanger and the first heat exchanger in sequence, and is connected to the gas-liquid separator unit through the first cooler, wherein the gas-liquid separator unit includes a gas-liquid separator, the input end of the gas-liquid separator is connected to the first cooler, the gas output port of the gas-liquid separator is connected to a CO2 gas cylinder, and the liquid output port is connected to the input end of the water tank.

[0007] Furthermore, the multi-stage oxidation reactor treatment unit includes a first oxidation reactor, a second oxidation reactor, and a third oxidation reactor; The mixed gas output end of the supercritical water gasification reactor unit is connected to the input end of the first oxidation reactor; the output end of the first oxidation reactor is connected to the input end of the second oxidation reactor, the output end of the second oxidation reactor is connected to the input end of the third oxidation reactor, and the output end of the third oxidation reactor is connected to the input end of the gas-liquid separator after passing through the third heat exchanger, the second heat exchanger, the first heat exchanger and the first cooler in sequence; The liquid oxygen output pipeline is sequentially provided with a liquid oxygen pump and an air preheater; wherein the liquid oxygen output pipeline is divided into three branches through the air preheater, one branch is connected to the liquid oxygen input end of the first oxidation reactor, one branch is connected to the liquid oxygen input end of the second oxidation reactor; and one branch is connected to the liquid oxygen input end of the third oxidation reactor.

[0008] Furthermore, a fourth heat exchanger is provided between the first oxidation reactor and the second oxidation reactor; a fifth heat exchanger is provided between the second oxidation reactor and the third oxidation reactor; and a second turbine is provided between the fourth heat exchanger and the fifth heat exchanger; A working fluid pump is provided at the working fluid output end of the steam reheat cycle power generation unit. The working fluid output end of the steam reheat cycle power generation unit passes through the fourth heat exchanger, the second turbine, the fifth heat exchanger and the first turbine in sequence and is used to supply heat to the outside world or form a working fluid heat circulation loop.

[0009] Furthermore, when the working fluid output end of the steam reheat cycle power generation unit is used to supply heat to the outside after passing through the fourth heat exchanger, the second turbine, the fifth heat exchanger and the first turbine in sequence, the output end of the fifth heat exchanger is connected to the input end of the first turbine, and the output end of the first turbine is provided with a heat generator, which is used to recover the steam after power generation through the heat generator to supply heat to the outside.

[0010] Furthermore, when the working fluid output end of the steam reheat cycle power generation unit passes through the fourth heat exchanger, the second turbine, the fifth heat exchanger and the first turbine in sequence to form a working fluid heat circulation loop, the output end of the fifth heat exchanger is connected to the input end of the first turbine, and the output end of the first turbine is connected to the working fluid input end of the steam reheat cycle power generation unit to form a heat circulation loop, wherein a second cooler is provided between the output end of the first turbine and the working fluid input end of the steam reheat cycle power generation unit.

[0011] Preferably, the supercritical water liquefaction reactor unit includes a supercritical water liquefaction reactor, a slag discharge unit is provided at the slag discharge output port of the supercritical water liquefaction reactor, the slag discharge unit includes a lock hopper, a third cooler is provided at the slag discharge output port of the supercritical water liquefaction reactor, and is connected to the slag discharge input end of the lock hopper through the third cooler; a water injection ball valve is provided on the water injection input port of the lock hopper, and a slag discharge needle valve is provided at the slag discharge output port of the lock hopper.

[0012] Preferably, the supercritical water gasification reactor unit comprises a supercritical water gasification reactor; The supercritical water gasification reactor is provided with an H2 separation membrane; The hydrogen output end of the supercritical water gasification reactor is connected to an H2 gas cylinder, and the mixed gas output end of the supercritical water gasification reactor is connected to the input end of the multi-stage oxidation reactor processing unit.

[0013] Preferably, the domestic waste preliminary processing unit includes a crusher and a mixer; The input end of the pulverizer is used to input domestic waste, and the output end of the pulverizer is connected to the material port of the mixer; the third water flow pipeline is connected to the liquid input end of the mixer, and a slurry pump is provided at the liquid output end of the mixer, and the slurry pump is connected to the input end of the supercritical water gasification reactor unit after passing through the supercritical water liquefaction reactor unit.

[0014] In a second aspect, the present invention further provides a method for treating domestic waste by supercritical water liquefaction-gasification multi-energy fusion, based on the above-mentioned domestic waste supercritical water liquefaction-gasification multi-energy fusion treatment system, comprising the following steps: Inputting domestic waste into a domestic waste preliminary treatment unit, and inputting water in a water tank into the domestic waste preliminary treatment unit through a third water flow pipeline, mixing the water with the domestic waste to form a waste slurry; inputting the waste slurry into a supercritical water liquefaction reactor unit to heat and liquefy it to obtain a liquefied product, and inputting the liquefied product into a supercritical water gasification reactor unit; The water in the water tank is pressurized and heated through the first water flow pipeline and then input into the supercritical water gasification reactor unit, the liquefied product is subjected to a gasification reaction to generate a hydrogen mixed gasification product, hydrogen is separated in the supercritical water gasification reactor unit, and the separated hydrogen is retained, and the remaining gasification product after separation enters the multi-stage oxidation reactor, and at the same time, the liquid oxygen output pipeline pressurizes and heats the liquid oxygen and inputs it into the multi-stage oxidation reactor treatment unit, the multi-stage oxidation reactor treatment unit sequentially oxidizes the remaining gasification product to obtain an oxidation product, and the oxidation product sequentially passes through the first water flow pipeline, the second water flow pipeline and the third water flow pipeline, wherein the water flowing into the supercritical water gasification reactor unit is preheated through the first water flow pipeline, the water flowing into the supercritical water liquefaction reactor unit is preheated through the second water flow pipeline, and the water flowing into the domestic waste preliminary treatment unit is preheated through the third water flow pipeline; The oxidation product flows into the gas-liquid separator unit through the third water flow pipeline to further release heat, and is separated into pure water by the gas-liquid separator unit and input into the water tank; The working fluid is input into the working fluid input end of the steam reheat cycle power generation unit, and the oxidation product is obtained by oxidation in the multi-stage oxidation reactor treatment unit, which is then heated and used to generate electricity. The waste heat after power generation is used to supply heat to the outside or is pumped to the working fluid input end of the steam reheat cycle power generation unit to form a working fluid heat circulation loop.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention provides a multi-energy fusion treatment system for supercritical water liquefaction and gasification of domestic waste. Through supercritical water liquefaction and gasification technology, efficient conversion of domestic waste is achieved. Domestic waste is liquefied or gasified in a supercritical water environment, releasing energy and substances therein. This energy can be converted into electrical energy or thermal energy, thereby improving resource utilization efficiency. Through the multi-stage oxidation reactor treatment unit and the first turbine, the system can further utilize the generated thermal energy for heating, thereby achieving cascade utilization and recovery of energy. The liquid oxygen used in the system acts as an oxidant, reacting with the mixed gas in the multi-stage oxidation reactor, which can reduce the emission of harmful substances and improve the environmental performance of the system.

[0016] Furthermore, the first, second, and third water pumps are respectively positioned on the three water pipelines, providing stable water pressure and flow as needed to ensure the normal operation of the supercritical water liquefaction reactor unit and the supercritical water gasification reactor unit. The third, second, and first heat exchangers are respectively positioned between the output of the multi-stage oxidation reactor treatment unit and the three water pipelines. These heat exchangers are capable of recovering the heat energy generated by the multi-stage oxidation reactor treatment unit and transferring it to the water entering the supercritical water reactor unit, achieving a preheating effect. This heat energy recovery mechanism not only improves the system's energy efficiency but also reduces energy consumption. The first cooler is positioned between the output of the multi-stage oxidation reactor treatment unit and the gas-liquid separator unit to further cool the water after it passes through the multi-stage oxidation reactor and heat exchanger. The gas-liquid separator separates the cooled water into gas and liquid, which serve as the system's circulating water, helping to reduce the system's reliance on external water resources and improve resource utilization efficiency.

[0017] Furthermore, the multi-stage oxidation reactor treatment unit helps to more thoroughly decompose organic matter in the gas and improve oxidation efficiency, thereby optimizing the overall reaction process. The liquid oxygen pump ensures a stable supply of liquid oxygen, providing the necessary oxidant for the multi-stage oxidation reactor. The setting of the air preheater not only preheats the liquid oxygen entering the oxidation reactor and improves the reaction efficiency, but also realizes precise control of the liquid oxygen flow rate of each oxidation reactor by supplying liquid oxygen in three branches. The heat generated by the multi-stage oxidation reactor is effectively utilized. Through the third heat exchanger, the second heat exchanger and the first heat exchanger, this heat is transferred to the water flow entering the supercritical water reactor unit, realizing the recovery and reuse of heat energy.

[0018] Furthermore, the fourth heat exchanger and the fifth heat exchanger are respectively arranged between the first oxidation reactor and the second oxidation reactor, and between the second oxidation reactor and the third oxidation reactor. These two heat exchangers can recover the heat energy generated by the oxidation reactor and transfer it to the working fluid in the steam reheat cycle power generation unit to achieve preheating of the working fluid. This heat energy recovery mechanism not only improves the energy utilization efficiency of the system, but also reduces the energy consumption required for heating the working fluid. The preheated working fluid is pressurized by the working fluid pump, and then heated by the fourth heat exchanger and the fifth heat exchanger in sequence, and finally enters the first turbine for expansion and work. In this process, the heat energy released by the working fluid is converted into mechanical energy, which can be used for power generation or heat supply. Alternatively, after completing the work, the working fluid can be returned to the system for recycling, realizing the continuous utilization of thermal energy.

[0019] Furthermore, the fourth and fifth heat exchangers preheat and heat the working fluid, fully utilizing the heat energy generated by the oxidation reactor and improving the system's thermal energy efficiency. Steam from the first turbine is recovered through the heat generator and reused for heating, achieving cascaded utilization and maximum recovery of thermal energy, reducing energy waste.

[0020] Furthermore, by forming a thermal cycle loop, the system can efficiently utilize the thermal energy in the working fluid. Although the working fluid's temperature drops after performing work in the first turbine, it still contains a certain amount of thermal energy. After being moderately cooled in the second cooler, the working fluid can re-enter the steam reheat cycle power generation unit for reheating and performing work, thus achieving the recycling of thermal energy. The design of the thermal cycle loop enables the system to operate continuously and stably, improving overall efficiency. The working fluid continuously releases and recovers thermal energy during the circulation process, significantly improving the system's thermal energy utilization efficiency.

[0021] Furthermore, the provision of the third cooler effectively reduces the temperature of the high-temperature solid residue discharged from the supercritical water liquefaction reactor, allowing it to safely enter the subsequent lock hopper for processing. The potential harm of high-temperature residue to equipment and personnel is avoided, ensuring the safety and reliability of the slag discharge process. The lock hopper realizes the stable storage and discharge of the residue. The water injection ball valve injects water into the lock hopper when needed to adjust the humidity and fluidity of the residue, which helps prevent the residue from clogging or over-drying in the lock hopper. The slag discharge needle valve provides precise control of the slag discharge process. By adjusting the opening of the slag discharge needle valve, the discharge speed and amount of the residue can be flexibly controlled to ensure that the slag discharge process is coordinated with the overall operation of the system and avoid interference with the system operation.

[0022] Furthermore, the H2 separation membrane installed inside the supercritical water gasification reactor can efficiently separate hydrogen from the complex reaction mixture during the reaction process, thereby improving the purity of the hydrogen and ensuring the continuous and stable output of hydrogen, providing a high-quality gas source for subsequent hydrogen collection and utilization. The separated hydrogen is directly connected to the H2 gas cylinder for storage through the hydrogen output terminal, thereby avoiding the loss and contamination of hydrogen during the transmission process and ensuring the effective utilization of hydrogen. The mixed gas generated by the supercritical water gasification reactor is connected to the multi-stage oxidation reactor processing unit through the mixed gas output terminal for further processing. This ensures that the harmful substances in the mixed gas can be effectively decomposed or converted, reducing the risk of environmental pollution. At the same time, the multi-stage oxidation reactor processing unit can also recycle and utilize the useful components in the mixed gas, thereby maximizing the utilization of resources.

[0023] Furthermore, the pulverizer can effectively crush domestic waste into fine particles, which not only increases the specific surface area of ​​the domestic waste but also facilitates uniform mixing during the subsequent stirring process. By receiving the pulverized domestic waste and liquid from the third water flow pipeline, the mixer can fully mix the waste particles and liquid to form a uniform slurry. This not only improves the efficiency and uniformity of the subsequent supercritical water liquefaction and gasification reactions, but also helps reduce energy consumption and blockage risks during the reaction process. The prepared slurry can be continuously and stably transported to the supercritical water liquefaction reactor unit via the slurry pump.

[0024] The present invention also provides a multi-energy fusion method for treating municipal solid waste using supercritical water liquefaction and gasification. In a primary municipal solid waste treatment unit, municipal solid waste is mixed with water from a water tank to form a waste slurry, providing a uniform waste slurry for subsequent supercritical water liquefaction and gasification treatment. The waste slurry is heated and liquefied within the supercritical water liquefaction reactor unit, producing a liquefied product. The liquefied product then enters the supercritical water gasification reactor unit for a gasification reaction, generating H₂, CH₄, CO, and CO₂. This method not only achieves efficient conversion of municipal solid waste but also improves energy yield and quality. Within the supercritical water gasification reactor unit, hydrogen is separated from the gasified product using hydrogen separation technology, preserving high-value hydrogen resources. Simultaneously, the remaining gasified product enters a multi-stage oxidation reactor for oxidation treatment, improving energy utilization and reducing environmental pollution. The oxidation product is preheated by the first, second, and third water flow lines, respectively, to feed the supercritical water gasification reactor unit, the supercritical water liquefaction reactor unit, and the primary municipal solid waste treatment unit, thereby recycling thermal energy. The steam reheat cycle power generation unit generates steam through a multi-stage oxidation reactor processing unit and performs work to generate electricity, thus realizing diversified utilization of energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1This is a first structural schematic diagram of a multi-energy fusion treatment system for supercritical water liquefaction-gasification of domestic waste according to an embodiment of the present invention; Figure 2 This is a second structural schematic diagram of the multi-energy fusion treatment system for supercritical water liquefaction-gasification of domestic waste in an embodiment of the present invention; In the figure: 1. first water pump; 2. second water pump; 3. third water pump; 4. first heat exchanger; 5. second heat exchanger; 6. third heat exchanger; 7. pulverizer; 8. mixer; 9. slurry pump; 10. supercritical water liquefaction reactor; 11. supercritical water gasification reactor; 12. first oxidation reactor; 13. fourth heat exchanger; 14. liquid oxygen pump; 15. air preheater; 16. second oxidation reactor; 17. working fluid pump; 18. first turbine; 19. fifth heat exchanger; 20. second turbine; 21. second cooler; 22. heat generator; 23. third oxidation reactor; 24. first cooler; 25. gas-liquid separator; 26. third cooler; 27. lock hopper; 28. H2 gas cylinder; 29. ​​CO2 gas cylinder; 30. water tank; 31. H2 separation membrane. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0027] The present invention is described in further detail below with reference to the accompanying drawings: Supercritical water gasification technology is an efficient, clean, and resource-rich method for treating municipal solid waste, converting it into hydrogen-rich syngas. In its supercritical state (the critical point of water is T = 374°C, P = 22.1 MPa), water exhibits low dielectric constant, high diffusivity, high reactivity, and low viscosity. These properties give it superior physicochemical properties, enabling efficient thermochemical conversion of organic matter. When organic waste enters a supercritical water environment, water molecules rapidly interact with the organic matter in this supercritical state, forming a homogeneous reaction system that significantly accelerates the decomposition process. In this environment, the reduced activation energy of the reaction causes chemical bonds within complex organic macromolecules to break and recombine, ultimately producing hydrogen and other small gas molecules. This process not only enables the efficient conversion of organic waste into new energy, but also reduces harmful gas emissions, enabling the production of clean energy. Supercritical water gasification technology offers significant advantages over traditional waste treatment methods. First, supercritical water can directly vaporize organic waste with a high water content, eliminating the energy-intensive drying process required by other technologies, significantly improving energy efficiency. Secondly, the high reactivity and low energy consumption during the supercritical water gasification process make it an ideal choice for resource utilization, which helps promote the green treatment and energy recovery of domestic waste and meets the requirements of sustainable development. Therefore, supercritical water gasification can not only achieve efficient and clean conversion of waste, but also has significant energy recovery potential, and is a technology worthy of key development in the field of future waste treatment. The purpose of the present invention is to provide a multi-energy fusion treatment system and method for supercritical water liquefaction-gasification of domestic waste to solve the technical problem of how to improve the effective utilization of domestic waste resources in the prior art.

[0028] Example 1 See also Figure 1 and Figure 2In one embodiment of the present invention, a multi-energy fusion treatment system for supercritical water liquefaction-gasification of domestic waste is provided, comprising a domestic waste preliminary treatment unit, a supercritical water liquefaction reactor unit, a supercritical water gasification reactor unit, a multi-stage oxidation reactor treatment unit, a liquid oxygen output pipeline, a steam reheat cycle power generation unit, a gas-liquid separator unit, a first turbine 18 and a water tank 30; the output end of the water tank 30 is provided with a first water flow pipeline, a second water flow pipeline and a third water flow pipeline; the first water flow pipeline is connected to the input end of the supercritical water gasification reactor unit; the second water flow pipeline is connected to the input end of the supercritical water gasification reactor unit through the supercritical water liquefaction reactor unit; the third water flow pipeline is connected to the supercritical water gasification reactor after passing through the domestic waste preliminary treatment unit and the supercritical water liquefaction reactor unit in sequence. The input end of the reactor unit; the supercritical water gasification reactor unit is used to separate hydrogen from the mixed gas, wherein the output end of the mixed gas is connected to the input end of the multi-stage oxidation reactor treatment unit; the output end of the multi-stage oxidation reactor treatment unit is connected to the gas-liquid separator unit after passing through the first water flow pipeline, the second water flow pipeline and the third water flow pipeline in sequence, for preheating the first water flow pipeline, the second water flow pipeline and the third water flow pipeline, and the output end of the gas-liquid separator unit is connected to the water tank 30; the output end of the liquid oxygen output pipeline is connected to the liquid oxygen input end of the multi-stage oxidation reactor treatment unit; the working fluid output end of the steam reheat cycle power generation unit is connected to the first turbine 18 through the multi-stage oxidation reactor treatment unit, and is used to supply heat to the outside world or form a working fluid heat circulation loop through the first turbine 18.

[0029] Specifically, a first water pump 1 and a third heat exchanger 6 are sequentially provided on the first water flow pipeline along the water flow direction; a second water pump 2 and a second heat exchanger 5 are sequentially provided on the second water flow pipeline along the water flow direction; a third water pump 3 and a first heat exchanger 4 are sequentially provided on the third water flow pipeline along the water flow direction; the output end of the multi-stage oxidation reactor treatment unit is provided with a first cooler 24 after passing through the third heat exchanger 6, the second heat exchanger 5 and the first heat exchanger 4 in sequence, and is connected to the gas-liquid separator unit through the first cooler 24, wherein the gas-liquid separator unit includes a gas-liquid separator 25, the input end of the gas-liquid separator 25 is connected to the first cooler 24, the gas output port of the gas-liquid separator 25 is connected to a CO2 gas cylinder 29, and the liquid output port is connected to the input end of the water tank 30.

[0030] In this embodiment, the first water pump 1, the second water pump 2 and the third water pump 3 provide power for the water flow pipelines in which they are located, ensuring that water can flow in a predetermined direction and flow rate. The third heat exchanger 6, the second heat exchanger 5 and the first heat exchanger 4 are respectively located on different water flow pipelines to achieve the exchange and recycling of heat energy. Through the preheating and cooling process, the thermal efficiency of the system is improved and the energy consumption is reduced. The first cooler 24 is located at the output end of the multi-stage oxidation reactor processing unit and is used to cool the oxidation product for subsequent gas-liquid separation treatment. The gas-liquid separator 25 separates the cooled oxidation product into gas and liquid to obtain pure gas and liquid. The gas portion can be collected and stored in the CO2 cylinder 29, and the liquid portion is returned to the water tank 30 for recycling.

[0031] In which, the multi-stage oxidation reactor processing unit includes a first oxidation reactor 12, a second oxidation reactor 16 and a third oxidation reactor 23; the mixed gas output end of the supercritical water gasification reactor unit is connected to the input end of the first oxidation reactor 12; the output end of the first oxidation reactor 12 is connected to the input end of the second oxidation reactor 16, the output end of the second oxidation reactor 16 is connected to the input end of the third oxidation reactor 23, and the output end of the third oxidation reactor 23 is connected to the input end of the gas-liquid separator 25 after passing through the third heat exchanger 6, the second heat exchanger 5, the first heat exchanger 4 and the first cooler 24 in sequence; a liquid oxygen pump 14 and an air preheater 15 are provided on the liquid oxygen output pipeline in sequence; wherein the liquid oxygen output pipeline is divided into three branches through the air preheater 15, one branch is connected to the liquid oxygen input end of the first oxidation reactor 12, one branch is connected to the liquid oxygen input end of the second oxidation reactor 16; and one branch is connected to the liquid oxygen input end of the third oxidation reactor 23.

[0032] In this embodiment, the first oxidation reactor 12, the second oxidation reactor 16, and the third oxidation reactor 23 are used to oxidize the vaporized product with liquid oxygen, gradually removing impurities and producing the target product. The liquid oxygen output pipeline includes a liquid oxygen pump 14 and an air preheater 15, which are used to provide the liquid oxygen required for the oxidation reaction and improve its utilization rate through preheating.

[0033] Among them, a fourth heat exchanger 13 is provided between the first oxidation reactor 12 and the second oxidation reactor 16; a fifth heat exchanger 19 is provided between the second oxidation reactor 16 and the third oxidation reactor 23; a second turbine 20 is provided between the fourth heat exchanger 13 and the fifth heat exchanger 19; a working fluid pump 17 is provided at the working fluid output end of the steam reheat cycle power generation unit, and the working fluid output end of the steam reheat cycle power generation unit is used to supply heat to the outside world or form a working fluid heat circulation loop after passing through the fourth heat exchanger 13, the second turbine 20, the fifth heat exchanger 19 and the first turbine 18 in sequence.

[0034] In this embodiment, the fourth heat exchanger 13 is located between the first oxidation reactor 12 and the second oxidation reactor 16, and is used to recover the heat energy generated by the first oxidation reactor 12 and transfer it to the working fluid in the steam reheat cycle power generation unit. The fifth heat exchanger 19 is located between the second oxidation reactor 16 and the third oxidation reactor 23, and is also used to recover heat energy and transfer it to the working fluid. The second turbine 20 is located between the fourth heat exchanger 13 and the fifth heat exchanger 19, and utilizes the expansion work of the working fluid under high temperature and high pressure to drive the generator to generate electricity. The first turbine 18 further utilizes the thermal energy of the working fluid to expand and perform work, thereby increasing the energy output of the system.

[0035] When the working fluid output end of the steam reheat cycle power generation unit is used to supply heat to the outside after passing through the fourth heat exchanger 13, the second turbine 20, the fifth heat exchanger 19 and the first turbine 18 in sequence, the output end of the fifth heat exchanger 19 is connected to the input end of the first turbine 18. The output end of the first turbine 18 is provided with a heat generator 22 for recovering steam after power generation through the heat generator 22 to supply heat to the outside. Figure 1 shown.

[0036] When the working medium output end of the steam reheat cycle power generation unit passes through the fourth heat exchanger 13, the second turbine 20, the fifth heat exchanger 19 and the first turbine 18 in sequence to form a working medium heat circulation loop, the output end of the fifth heat exchanger 19 is connected to the input end of the first turbine 18, and the output end of the first turbine 18 is connected to the working medium input end of the steam reheat cycle power generation unit to form a heat circulation loop, wherein a second cooler 21 is provided between the output end of the first turbine 18 and the working medium input end of the steam reheat cycle power generation unit. Figure 2 shown.

[0037] Specifically, the supercritical water liquefaction reactor unit includes a supercritical water liquefaction reactor 10, a slag discharge unit is provided at the slag discharge output port of the supercritical water liquefaction reactor 10, and the slag discharge unit includes a lock hopper 27, a third cooler 26 is provided at the slag discharge output port of the supercritical water liquefaction reactor 10, and is connected to the slag discharge input end of the lock hopper 27 through the third cooler 26; a water injection ball valve is provided on the water injection input port of the lock hopper 27, and a slag discharge needle valve is provided at the slag discharge output port of the lock hopper 27.

[0038] In this embodiment, the supercritical water liquefaction reactor 10 converts domestic waste or other organic matter into liquid products under a supercritical state. The supercritical state refers to the state of a substance when it is above its critical temperature and critical pressure. At this time, the properties of the substance are between the gaseous state and the liquid state, which is conducive to the progress of chemical reactions. The third cooler 26 is located at the slag discharge outlet of the supercritical water liquefaction reactor 10 and is used to cool the solid residue discharged from the supercritical water liquefaction reactor 10. The cooled residue is easier to handle and store, while avoiding damage to subsequent equipment caused by high-temperature residue; the lock hopper 27 is used to receive and temporarily store the solid residue after cooling by the third cooler 26. The lock hopper 27 prevents the residue from leaking during the discharge process, ensuring the safety and stability of the system.

[0039] Specifically, the supercritical water gasification reactor unit includes a supercritical water gasification reactor 11; an H2 separation membrane 31 is provided in the supercritical water gasification reactor 11; the hydrogen output end of the supercritical water gasification reactor 11 is connected to the H2 gas cylinder 28, and the mixed gas output end of the supercritical water gasification reactor 11 is connected to the input end of the multi-stage oxidation reactor treatment unit.

[0040] In this embodiment, the supercritical water gasification reactor 11 converts organic matter into a hydrogen-rich mixed gas under a supercritical state. Supercritical water has a strong dissolving power and can dissolve various organic matter. It is rapidly vaporized under high temperature and high pressure conditions to produce gaseous products. The supercritical water gasification reactor 11 is provided with an H2 separation membrane 31 for separating hydrogen from the mixed gas. The H2 separation membrane 31 has selective permeability, allowing hydrogen molecules to pass through while preventing other gas molecules from passing through, thereby achieving hydrogen purification. The H2 gas cylinder 28 is connected to the hydrogen output end of the supercritical water gasification reactor 11 and is used to store the hydrogen separated from the mixed gas.

[0041] Specifically, the domestic waste preliminary treatment unit includes a pulverizer 7 and a mixer 8; the input end of the pulverizer 7 is used to input domestic waste, and the output end of the pulverizer 7 is connected to the material port of the mixer 8; the third water flow pipeline is connected to the liquid input end of the mixer 8, and a slurry pump 9 is provided at the liquid output end of the mixer 8, and the liquid is connected to the input end of the supercritical water gasification reactor unit after passing through the supercritical water liquefaction reactor unit through the slurry pump 9.

[0042] In this embodiment, pulverizer 7 is used to pulverize the input domestic waste, converting it into smaller particles or powdered material to facilitate subsequent mixing and reaction processing. Agitator 8 mixes and stirs the pulverized domestic waste with liquid from the third water flow pipeline to form a uniform slurry. Agitator 8 typically has efficient stirring capacity and sealing performance to ensure the uniformity and stability of the slurry. A slurry pump 9 is used to pump the slurry formed in agitator 8 to the supercritical water liquefaction reactor unit.

[0043] In this embodiment, a supercritical water liquefaction reactor 10 is added before the supercritical water gasification reactor 11. The organic matter in the domestic waste enters the supercritical water through liquefaction at a lower temperature, forming a homogeneous reaction system. The supercritical water liquefaction reactor 10 is provided with a slag discharge unit, which can discharge slag at a lower temperature. An H2 separation membrane 31 is provided in the supercritical water gasification reactor 11 to separate hydrogen online. The system is designed with three oxidation reactors to oxidize the gasification products after hydrogen separation multiple times to provide heat for the system's raw material preheating and supercritical steam reheat cycle power generation. On the basis of hydrogen production and power generation, a heat generator 22 is coupled to recover waste heat for heating and reduce system energy loss. The system not only realizes the resource treatment of domestic waste and improves system efficiency, but also achieves the goal of multi-generation of hydrogen production, power generation and heat supply.

[0044] In summary, the present embodiment provides a multi-energy fusion treatment system for supercritical water liquefaction-gasification of domestic waste. Through supercritical water liquefaction and gasification technology, the efficient conversion of domestic waste is achieved. Domestic waste is liquefied or gasified in a supercritical water environment, releasing the energy and substances therein. These energies can be converted into electrical energy or thermal energy, thereby improving the efficiency of resource utilization. Through the multi-stage oxidation reactor treatment unit and the first turbine 18, the system can further utilize the generated heat energy for heating, thereby realizing the cascade utilization and recovery of energy. The liquid oxygen used in the system is used as an oxidant to react with the mixed gas in the multi-stage oxidation reactor, which can reduce the emission of harmful substances and improve the environmental performance of the system. The present invention uses supercritical water gasification technology to efficiently convert domestic waste into hydrogen, thereby realizing the resource utilization of waste. At the same time, it also effectively reduces the cost of domestic waste treatment and promotes green development. The present invention also obtains additional electrical energy and thermal energy on the basis of hydrogen production, which not only reduces energy loss but also brings added value.

[0045] Example 2 This embodiment also provides a method for treating domestic waste by supercritical water liquefaction-gasification multi-energy fusion, based on the above-mentioned domestic waste supercritical water liquefaction-gasification multi-energy fusion treatment system, including the following process: The domestic garbage is input into the pulverizer 7 for crushing, and then the crushed domestic garbage is input into the mixer 8, and the third water pump 3 is turned on so that the third water flow pipeline pumps the water in the water tank 30 preheated by the first heat exchanger 4 into the mixer 8 to mix with the domestic garbage to form a garbage slurry.

[0046] The second water pump 2 is turned on to pump the water in the water tank 30 through the second water flow pipeline and the garbage slurry pump 9 into the supercritical water liquefaction reactor 10 for heating and liquefaction; wherein the supercritical water liquefaction reactor 10 is provided with a slag discharge unit. When discharging slag, the water injection ball valve is opened, water is injected into the lock hopper 27, and then the ball valve is closed. The slag discharge needle valve is then quickly opened. The slag particles at the bottom of the supercritical water liquefaction reactor 10 are transported to the third cooler 26 for cooling due to the pressure difference, and the mixture enters the lock hopper 27. When the pressure of the entire system reaches equilibrium, the slag discharge needle valve will be closed. The ball valve is then opened, and the liquid-solid mixture in the lock hopper 27 is discharged.

[0047] The first water pump 1 is turned on to pressurize the water in the water tank 30 through the first water flow pipeline and heat it through the third heat exchanger 6, and then enters the supercritical water gasification reactor 11. At the same time, the liquefied product of the supercritical water liquefaction reactor 10 enters the supercritical water gasification reactor 11 for gasification to generate H2, CH4, CO and CO2. The supercritical water gasification reactor 11 is provided with an H2 separation membrane 31. H2 can pass through the H2 separation membrane 31 and collect on the permeate side, while other mixed gases cannot pass through the H2 separation membrane 31 and are retained on the retentate side, thereby achieving H2 separation. The pure hydrogen after separation is collected through the pressure reducing valve and enters the H2 gas cylinder 28. Among them, the heating device on the outside of the gasification reactor is turned on for the system startup process at the initial stage of system operation, and is turned off after the system runs smoothly.

[0048] Liquid oxygen is pressurized in the liquid oxygen output pipeline by a liquid oxygen pump 14, preheated by an air preheater 15, and then divided into three branches, entering the first oxidation reactor 12, the second oxidation reactor 16, and the third oxidation reactor 23, respectively. The remaining vaporized product after H2 separation flows into the first oxidation reactor 12 for oxidation, and the oxidation product flows into the fourth heat exchanger 13. The oxidation product flowing through the fourth heat exchanger 13 flows into the second oxidation reactor 16 for secondary oxidation, and the secondary oxidation product flows into the fifth heat exchanger 19. The oxidation product flowing through the fifth heat exchanger 19 flows into the third oxidation reactor 23 for tertiary oxidation, and the tertiary oxidation product flows into the third heat exchanger 6 to preheat the water flowing into the supercritical water gasification reactor 11. It then flows into the second heat exchanger 5 to preheat the water flowing into the supercritical water liquefaction reactor 10, and finally flows into the first heat exchanger 4 to preheat the water flowing into the mixer 8.

[0049] The oxidation products flowing through the first heat exchanger 4 release further heat in the first cooler 24, and are separated into pure water by the gas-liquid separator 25. The pure water then flows through the pressure reducing valve into the water tank 30 and is then fed into the system for circulation. The remaining pure CO2 flows through the pressure reducing valve into the CO2 cylinder 29.

[0050] When the working medium H2O absorbs the heat of the oxidation products from the fourth heat exchanger 13, it generates steam at a certain pressure and temperature. The working medium steam enters the second turbine 20, performs work and generates electricity. It then flows through the fifth heat exchanger 19 again to absorb the heat of the secondary oxidation products, and enters the first turbine 18 to provide heat to the outside world. The heat generator 22 recovers the steam after the work and electricity generation and provides heat to the outside world. Figure 1 shown.

[0051] After the supercritical steam reheat cycle working medium H2O is pressurized by the working medium pump 17 at the working medium output end of the steam reheat cycle power generation unit, it absorbs heat from the oxidation products from the fourth heat exchanger 13, generating steam at a certain pressure and temperature. The working medium steam enters the second turbine 20, performs work to generate electricity. After passing through the fifth heat exchanger 19 to increase the temperature again, it enters the first turbine 18 to work and generate electricity. The working medium is cooled to room temperature in the second cooler 21 and returns to the working medium input end of the steam reheat cycle power generation unit through the working medium pump 17, forming a working medium heat circulation loop. Figure 2 shown.

[0052] This embodiment adopts the method of liquefaction followed by gasification, which effectively prevents the generation of coke from high-concentration biomass during the supercritical water gasification process, thereby avoiding the problem of reactor blockage. Based on the supercritical water gasification of domestic waste to produce hydrogen, a three-stage oxidation process is adopted. The heat of the oxidation products in the first two oxidizers is used to perform supercritical steam reheat cycle power generation to obtain electrical energy. The heat of the oxidation products in the last oxidizer is used to preheat the raw materials. The waste heat after the supercritical steam reheat cycle power generation is recovered by the heat generator 22, and the waste heat is recovered for heating to reduce energy waste. This embodiment is suitable for situations where there is still a lot of waste heat left after the reheat cycle power generation.

[0053] In this embodiment, the ion-based reaction in the supercritical water liquefaction reactor 10 is dominant. The organic matter in the domestic waste is first dissolved in supercritical water through liquefaction at a relatively low temperature to form a homogeneous reaction system. This avoids coking and clogging of the reactor due to excessive concentration during direct gasification of domestic waste, thereby meeting the treatment needs of high-concentration domestic waste. The use of steam reheat cycle power generation can increase the power generation of the system and effectively improve power generation efficiency. This system can also continue to couple waste heat recovery for heat supply based on supercritical water gasification hydrogen production coupled with steam reheat cycle power generation, effectively reducing the energy loss of the system and being applicable to a variety of different situations. The pure water separated from the gas and liquid can be re-input into the system for circulation, reducing the energy input of the system.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A domestic waste supercritical water liquefaction-gasification multi-energy fusion treatment system, characterized in that: It comprises a domestic waste preliminary treatment unit, a supercritical water liquefaction reactor unit, a supercritical water gasification reactor unit, a multi-stage oxidation reactor treatment unit, a liquid oxygen output pipeline, a steam reheat cycle power generation unit, a gas-liquid separator unit, a first turbine (18) and a water tank (30); The output end of the water tank (30) is provided with a first water flow pipeline, a second water flow pipeline and a third water flow pipeline; the first water flow pipeline is connected to the input end of the supercritical water gasification reactor unit; the second water flow pipeline is connected to the input end of the supercritical water gasification reactor unit via the supercritical water liquefaction reactor unit; the third water flow pipeline is connected to the input end of the supercritical water gasification reactor unit after passing through the domestic waste preliminary treatment unit and the supercritical water liquefaction reactor unit in sequence; The supercritical water gasification reactor unit is used to separate hydrogen from the mixed gas, wherein the mixed gas output end is connected to the input end of the multi-stage oxidation reactor processing unit; the output end of the multi-stage oxidation reactor processing unit is connected to the gas-liquid separator unit after passing through the first water flow pipeline, the second water flow pipeline and the third water flow pipeline in sequence, and is used to preheat the first water flow pipeline, the second water flow pipeline and the third water flow pipeline, and the output end of the gas-liquid separator unit is connected to the water tank (30); The output end of the liquid oxygen output pipeline is connected to the liquid oxygen input end of the multi-stage oxidation reactor processing unit; The working medium output end of the steam reheat cycle power generation unit is connected to the first turbine (18) via the multi-stage oxidation reactor processing unit, and is used to supply heat to the outside or form a working medium heat circulation loop after passing through the first turbine (18).

2. A domestic waste supercritical water liquefaction-gasification multi-energy fusion treatment system according to claim 1, characterized in that: The first water flow pipeline is provided with a first water pump (1) and a third heat exchanger (6) in sequence along the water flow direction; the second water flow pipeline is provided with a second water pump (2) and a second heat exchanger (5) in sequence along the water flow direction; the third water flow pipeline is provided with a third water pump (3) and a first heat exchanger (4) in sequence along the water flow direction; The output end of the multi-stage oxidation reactor treatment unit is provided with a first cooler (24) after passing through the third heat exchanger (6), the second heat exchanger (5) and the first heat exchanger (4) in sequence, and is connected to the gas-liquid separator unit through the first cooler (24), wherein the gas-liquid separator unit comprises a gas-liquid separator (25), the input end of the gas-liquid separator (25) is connected to the first cooler (24), the gas output port of the gas-liquid separator (25) is connected to a CO2 gas cylinder (29), and the liquid output port is connected to the input end of a water tank (30).

3. A domestic waste supercritical water liquefaction-gasification multi-energy fusion treatment system according to claim 2, characterized in that: The multi-stage oxidation reactor treatment unit comprises a first oxidation reactor (12), a second oxidation reactor (16) and a third oxidation reactor (23); The mixed gas output end of the supercritical water gasification reactor unit is connected to the input end of the first oxidation reactor (12); the output end of the first oxidation reactor (12) is connected to the input end of the second oxidation reactor (16); the output end of the second oxidation reactor (16) is connected to the input end of the third oxidation reactor (23); the output end of the third oxidation reactor (23) is connected to the input end of the gas-liquid separator (25) after passing through the third heat exchanger (6), the second heat exchanger (5), the first heat exchanger (4) and the first cooler (24) in sequence; The liquid oxygen output pipeline is provided with a liquid oxygen pump (14) and an air preheater (15) in sequence; wherein the liquid oxygen output pipeline is divided into three branches through the air preheater (15), one branch is connected to the liquid oxygen input end of the first oxidation reactor (12), one branch is connected to the liquid oxygen input end of the second oxidation reactor (16); and one branch is connected to the liquid oxygen input end of the third oxidation reactor (23).

4. A domestic waste supercritical water liquefaction-gasification multi-energy fusion treatment system according to claim 3, characterized in that: A fourth heat exchanger (13) is provided between the first oxidation reactor (12) and the second oxidation reactor (16); a fifth heat exchanger (19) is provided between the second oxidation reactor (16) and the third oxidation reactor (23); and a second turbine (20) is provided between the fourth heat exchanger (13) and the fifth heat exchanger (19); A working fluid pump (17) is provided at the working fluid output end of the steam reheat cycle power generation unit. The working fluid output end of the steam reheat cycle power generation unit is sequentially passed through a fourth heat exchanger (13), a second turbine (20), a fifth heat exchanger (19) and a first turbine (18) for supplying heat to the outside or forming a working fluid heat circulation loop.

5. A domestic waste supercritical water liquefaction-gasification multi-energy fusion treatment system according to claim 4, characterized in that: When the working fluid output end of the steam reheat cycle power generation unit is used to supply heat to the outside after passing through the fourth heat exchanger (13), the second turbine (20), the fifth heat exchanger (19) and the first turbine (18) in sequence, the output end of the fifth heat exchanger (19) is connected to the input end of the first turbine (18), and the output end of the first turbine (18) is provided with a heat generator (22) for recovering steam after power generation through the heat generator (22) to supply heat to the outside.

6. A domestic waste supercritical water liquefaction-gasification multi-energy fusion treatment system according to claim 4, characterized in that: When the working fluid output end of the steam reheat cycle power generation unit is used to form a working fluid heat cycle loop after passing through the fourth heat exchanger (13), the second turbine (20), the fifth heat exchanger (19) and the first turbine (18) in sequence, the output end of the fifth heat exchanger (19) is connected to the input end of the first turbine (18), and the output end of the first turbine (18) is connected to the working fluid input end of the steam reheat cycle power generation unit to form a heat cycle loop, wherein a second cooler (21) is provided between the output end of the first turbine (18) and the working fluid input end of the steam reheat cycle power generation unit.

7. The system for treating domestic waste by supercritical water liquefaction-gasification multi-energy fusion according to claim 1, characterized in that: The supercritical water liquefaction reactor unit comprises a supercritical water liquefaction reactor (10); a slag discharge unit is provided at a slag discharge outlet of the supercritical water liquefaction reactor (10); the slag discharge unit comprises a lock hopper (27); a third cooler (26) is provided at the slag discharge outlet of the supercritical water liquefaction reactor (10), and the third cooler (26) is connected to a slag discharge input end of the lock hopper (27); a water injection ball valve is provided on a water injection input port of the lock hopper (27); and a slag discharge needle valve is provided at a slag discharge output port of the lock hopper (27).

8. The system for treating domestic waste by supercritical water liquefaction-gasification multi-energy fusion according to claim 1, characterized in that: The supercritical water gasification reactor unit comprises a supercritical water gasification reactor (11); The supercritical water gasification reactor (11) is provided with a H2 separation membrane (31); The hydrogen output end of the supercritical water gasification reactor (11) is connected to an H2 gas cylinder (28), and the mixed gas output end of the supercritical water gasification reactor (11) is connected to the input end of the multi-stage oxidation reactor processing unit.

9. The system for treating domestic waste by supercritical water liquefaction-gasification multi-energy fusion according to claim 1, characterized in that: The domestic waste preliminary processing unit comprises a pulverizer (7) and a mixer (8); The input end of the pulverizer (7) is used to input domestic waste, and the output end of the pulverizer (7) is connected to the material port of the mixer (8); the third water flow pipeline is connected to the liquid input end of the mixer (8), and a slurry pump (9) is provided at the liquid output end of the mixer (8), and is connected to the input end of the supercritical water gasification reactor unit after passing through the supercritical water liquefaction reactor unit through the slurry pump (9).

10. A method for treating domestic waste by supercritical water liquefaction-gasification multi-energy fusion, characterized in that: A multi-energy fusion treatment system for supercritical water liquefaction-gasification of domestic waste according to any one of claims 1 to 9 comprises the following steps: Inputting domestic waste into a domestic waste preliminary treatment unit, and inputting water in a water tank (30) into the domestic waste preliminary treatment unit through a third water flow pipeline, and mixing the water with the domestic waste to form a waste slurry; inputting the waste slurry into a supercritical water liquefaction reactor unit to heat and liquefy it to obtain a liquefied product, and inputting the liquefied product into a supercritical water gasification reactor unit; The water in the water tank (30) is pressurized and heated through a first water flow pipeline and then fed into a supercritical water gasification reactor unit, a liquefied product is subjected to a gasification reaction to generate a hydrogen mixed gasification product, hydrogen is separated in the supercritical water gasification reactor unit, and the separated hydrogen is retained, and the remaining gasification product after separation enters a multi-stage oxidation reactor, and at the same time, the liquid oxygen output pipeline pressurizes and heats the liquid oxygen and then feeds it into a multi-stage oxidation reactor processing unit, and the multi-stage oxidation reactor processing unit sequentially oxidizes the remaining gasification product to obtain an oxidation product, and the oxidation product sequentially passes through a first water flow pipeline, a second water flow pipeline, and a third water flow pipeline, wherein the first water flow pipeline is used to preheat the water flowing into the supercritical water gasification reactor unit, the second water flow pipeline is used to preheat the water flowing into the supercritical water liquefaction reactor unit, and the third water flow pipeline is used to preheat the water flowing into the primary treatment unit for domestic waste; The oxidation product flows into the gas-liquid separator unit through the third water flow pipeline to further release heat, and is separated into pure water by the gas-liquid separator unit and input into the water tank (30); The working fluid is input into the working fluid input end of the steam reheat cycle power generation unit, oxidized by the multi-stage oxidation reactor treatment unit to obtain oxidation products, which are then heated and work is performed to generate electrical energy. The waste heat after power generation is used to supply heat to the outside or is pumped to the working fluid input end of the steam reheat cycle power generation unit to form a working fluid heat circulation loop.

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