Solar comprehensive high-efficiency hydrogen production and energy supply system and operation method thereof

Abstract

This invention provides a solar-powered integrated high-efficiency hydrogen production and energy supply system and its operation method, relating to the field of energy utilization technology. The system includes a solar thermal collector unit, a thermochemical hydrogen production unit, a supercritical carbon dioxide power cycle unit, and a heat recovery and supply unit. The solar thermal collector unit captures and converts solar energy into heat energy, driving the thermochemical hydrogen production unit to continuously produce hydrogen and oxygen. The waste heat from the high-temperature hydrogen and oxygen produced during hydrogen production, as well as the waste heat from solar energy, is used to heat the working fluid of the supercritical carbon dioxide power cycle, driving the turbine to generate electricity. The system also utilizes a three-stage heat recovery process to recover the waste heat from the carbon dioxide working fluid after power generation, as well as the cooling heat from the high-temperature hydrogen and oxygen, for the production of domestic hot water and heating for end users. This invention achieves efficient and synergistic conversion and comprehensive utilization of solar energy into multiple energy forms, including hydrogen, oxygen, electricity, and heat. It features high system integration, high energy utilization, and significant economic and environmental benefits.

Description

Technical Field

[0001] This invention relates to the field of energy utilization technology, specifically to a solar-powered integrated high-efficiency hydrogen production and power supply system and its operation method. Background Technology

[0002] With the acceleration of the global energy transition, the development and utilization of clean and renewable solar energy has become a consensus. Solar-powered hydrogen production is one of the effective ways to achieve large-scale storage and transportation of solar energy. Currently, the mainstream solar-powered hydrogen production technologies include photovoltaic water electrolysis and photothermal chemical cycle hydrogen production.

[0003] Photovoltaic electrolysis for hydrogen production is a mature technology, but its overall energy efficiency and economic benefits need improvement due to limitations in photovoltaic power generation efficiency, electrolyzer costs, and dependence on the power grid. Photothermal-chemical cycle hydrogen production, particularly metal oxide cycles, sulfur-iodine cycles, and vanadium-chlorine cycles, can directly utilize solar thermal energy to drive water splitting reactions, theoretically possessing higher energy conversion efficiency potential. Among these, the vanadium-chlorine cycle has attracted attention due to its advantages such as moderate reaction temperature, recyclable materials, and zero carbon emissions.

[0004] In existing technologies, purely solar-powered hydrogen production systems often only produce hydrogen gas, failing to fully utilize the high-grade heat generated during the reaction process (such as the heat energy carried by high-temperature hydrogen and oxygen) and the system's waste heat, resulting in low overall solar energy utilization efficiency. In addition, when a separate power generation system (such as a traditional steam Rankine cycle) is coupled with a hydrogen production system, the energy integration is low and the system is complex.

[0005] Therefore, there is an urgent need for a comprehensive energy supply system that can achieve efficient utilization of solar energy in stages, simultaneously produce hydrogen, oxygen, electricity and heat, and has a high degree of system integration and tight energy coupling. Summary of the Invention

[0006] To address the aforementioned problems, this invention proposes a solar-powered integrated high-efficiency hydrogen production and power supply system and its operation method. This invention can simultaneously meet the industrial production demands for H2 and O2, as well as the end-user's requirements for electricity and hot water, thus improving the utilization efficiency of solar energy resources. Furthermore, the electricity generated by this solar-powered high-efficiency hydrogen production system can also supply some electrical devices within the system, maintaining stable system operation and reducing the operating costs of system equipment.

[0007] To achieve the above-mentioned technical features, the objective of this invention is as follows: The first aspect provides a solar-powered integrated high-efficiency hydrogen production and energy supply system, including: Solar thermal collectors are used to capture and convert solar energy into thermal energy. A thermochemical hydrogen production unit, thermally connected to the solar collector unit, is used to drive at least one thermochemical reaction to produce hydrogen and oxygen using the thermal energy. The supercritical carbon dioxide power cycle unit is thermally connected to the thermochemical hydrogen production unit. It is used to recover the waste heat of the high-temperature products generated by the thermochemical hydrogen production unit and the residual heat energy of the solar thermal collector unit, and to generate electricity by doing work through the expansion of supercritical carbon dioxide. In addition, a heat recovery and supply unit is connected to the supercritical carbon dioxide power cycle unit and the thermochemical hydrogen production unit to recover the waste heat of the working fluid and products in the system and supply heat energy to the user end.

[0008] Preferably, the thermochemical hydrogen production unit is a vanadium-chlorine cycle hydrogen production system, comprising a high-temperature reactor, a medium-temperature reactor, and a low-temperature reactor connected in sequence. The high-temperature reactor is used to thermally decompose vanadium trichloride at a first temperature to generate chlorine gas and vanadium dichloride. The low-temperature reactor is used to react the chlorine gas with water at a second temperature to produce hydrogen chloride and oxygen. The intermediate-temperature reactor is used to react the vanadium dichloride with the hydrogen chloride at a third temperature to generate hydrogen gas and regenerated vanadium trichloride, the regenerated vanadium trichloride being returned to the high-temperature reactor; Wherein, the first temperature is higher than the third temperature, and the third temperature is higher than the second temperature.

[0009] Preferably, the first temperature is 798±20K, the second temperature is 373±10K, and the third temperature is 573±20K.

[0010] Preferably, the supercritical carbon dioxide power cycle unit includes a compressor, a regenerator, at least one first-stage heater, a turbine, and a condenser connected in sequence by pipelines; The carbon dioxide working fluid from the compressor outlet flows sequentially through the cold side of the regenerator and the first stage heater, and is heated to a supercritical state before entering the turbine to expand and do work. After performing work, the carbon dioxide working fluid flows sequentially through the hot side of the regenerator and the condenser to cool down before returning to the compressor.

[0011] Preferably, the at least one first-stage heater includes a first heat exchanger and a second heat exchanger; The first heat exchanger is configured to exchange heat between the carbon dioxide working fluid and the high-temperature oxygen produced by the thermochemical hydrogen production unit. The second heat exchanger is configured to exchange heat between the carbon dioxide working fluid and the high-temperature hydrogen produced by the thermochemical hydrogen production unit.

[0012] Preferably, the heat recovery and supply unit includes: The first-stage heat recovery module, including the regenerator and condenser, is used to recover the waste heat of the carbon dioxide working fluid after it has done work in the supercritical carbon dioxide power cycle unit, and to preheat the working fluid and / or prepare domestic hot water. The second-stage heat recovery module is connected to the oxygen output terminal of the thermochemical hydrogen production unit and is used to recover the waste heat of the oxygen and provide heating for the user end. The third-stage heat recovery module is connected to the hydrogen output terminal of the thermochemical hydrogen production unit and is used to recover the waste heat of the hydrogen and provide heating for the user.

[0013] Preferably, it also includes a gas collection device, and an oxygen collection device and a hydrogen collection device are respectively connected downstream of the second-stage heat recovery module and the third-stage heat recovery module.

[0014] Another aspect of the present invention provides an operation method for the aforementioned integrated high-efficiency hydrogen production and energy supply system based on solar energy, comprising the following steps: S1: Utilize solar thermal collectors to capture solar energy and convert it into thermal energy; S2: The thermal energy is transferred to the thermochemical hydrogen production unit to drive a multi-stage thermochemical reaction to continuously produce hydrogen and oxygen. S3: The high-temperature hydrogen and high-temperature oxygen produced by the thermochemical hydrogen production unit, as well as the residual heat energy of the solar thermal collector unit, are used to heat the carbon dioxide working fluid in the supercritical carbon dioxide power cycle unit. S4: The carbon dioxide working fluid, heated to a supercritical state, expands and does work, driving the generator to generate electricity; S5: Perform cascaded waste heat recovery on the carbon dioxide working fluid after work is done, as well as the high-temperature hydrogen and high-temperature oxygen generated in step S2. The recovered heat energy is used for internal system preheating and / or to supply domestic hot water and heating to users.

[0015] Preferably, step S2 specifically includes: S21: In a high-temperature reactor, the thermal energy is used to thermally decompose vanadium trichloride into chlorine gas and vanadium dichloride. S22: In a low-temperature reactor, the chlorine gas reacts with water to produce hydrogen chloride and oxygen; S23: In a medium-temperature reactor, the vanadium dichloride reacts with the hydrogen chloride to generate hydrogen gas and regenerated vanadium trichloride. S24: Return the regenerated vanadium trichloride to step S21 for recycling.

[0016] Preferably, in step S5, the cascade waste heat recovery includes: The carbon dioxide working fluid, after performing work, is used to preheat the carbon dioxide working fluid that is about to enter the heating process in the regenerator, and then it exchanges heat with tap water in the condenser to produce domestic hot water. The high-temperature oxygen is sequentially exchanged with carbon dioxide working fluid and user-end heating medium before being cooled and stored. The high-temperature hydrogen gas is sequentially exchanged with carbon dioxide working fluid and user-end heating medium before being cooled and stored.

[0017] The present invention has the following beneficial effects: 1. The system of this invention converts solar energy into four products in one go: hydrogen, oxygen, electricity, and heat, which meets the needs of industrial raw materials, clean energy, and residential energy use, and greatly improves the comprehensive utilization rate and economic value of solar energy.

[0018] 2. This invention couples the vanadium-chlorine cycle with the supercritical carbon dioxide Brayton cycle. Utilizing the heat from the high-temperature hydrogen and oxygen produced during hydrogen production as a high-temperature heat source for the CO2 cycle, it achieves efficient conversion of high-grade heat (power generation). Simultaneously, it deeply recovers the medium- and low-temperature waste heat after power generation and the cooling heat from the products for heating, forming a complete energy cascade utilization chain.

[0019] 3. This invention employs a thermochemical cycle for hydrogen production, consuming only water and solar energy. Reactants are recycled, resulting in zero carbon emissions throughout the entire process. Compared to traditional steam cycles, the supercritical CO2 cycle offers advantages such as a compact system and high efficiency. The system also generates and uses a portion of its own electricity, reducing operating costs. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Figure 1 This is a schematic diagram of the structure of a solar-powered integrated high-efficiency hydrogen production and energy supply system according to an embodiment of the present invention.

[0022] In the diagram: 1. Tower-type solar collector; 2. V-Cl high-temperature reactor; 3. V-Cl medium-temperature reactor; 4. Cl-H2O low-temperature reactor; 5. Second heat exchanger; 6. H2 cooling heat recovery device; 7. H2 collection device; 8. Supercritical CO2 turbine; 9. Generator; 10. Regenerator; 11. Condenser; 12. Compressor; 13. First heat exchanger; 14. O2 cooling heat recovery device; 15. O2 collection device. Detailed Implementation

[0023] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. This example is implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following embodiments.

[0024] Example 1: Basic System Structure and Operation like Figure 1 As shown in the figure, this embodiment provides a typical solar-powered integrated high-efficiency hydrogen production and energy supply system.

[0025] The solar thermal collector unit adopts a tower-type solar thermal collector field 1, in which the heat transfer oil flowing inside absorbs the concentrated solar energy and converts it into high-temperature heat energy.

[0026] The thermochemical hydrogen production unit employs a vanadium-chlorine (V-Cl) cycle system, comprising a V-Cl high-temperature reactor 2, a V-Cl medium-temperature reactor 3, and a Cl-H2O low-temperature reactor 4. Heat transfer oil flows sequentially through these three reactors, providing temperature environments of approximately 798 K, 573 K, and 373 K for the thermal decomposition of VCl3, the reaction of HCl with VCl2, and the reaction of Cl2 with water, respectively. In the V-Cl high-temperature reactor 2, VCl3 thermally decomposes into VCl2 and Cl2. Cl2 enters the Cl-H2O low-temperature reactor 4 and reacts with water to produce HCl and O2. The generated HCl reacts with VCl2 from the V-Cl high-temperature reactor 2 in the V-Cl medium-temperature reactor 3 to produce H2 and regenerated VCl3. The regenerated VCl3 returns to the V-Cl high-temperature reactor 2, achieving the recycling of vanadium and chlorine materials.

[0027] The supercritical carbon dioxide power cycle unit includes a compressor 12, a regenerator 10, a first heat exchanger 13, a second heat exchanger 5, a supercritical CO2 turbine 8, a generator 9, and a condenser 11. After being pressurized by the compressor 12, the CO2 working fluid is first preheated in the regenerator 10, then exchanges heat with high-temperature O2 from the Cl-H2O cryogenic reactor 4 in the first heat exchanger 13, and then exchanges heat with high-temperature H2 from the V-Cl mesophilic reactor 3 in the second heat exchanger 5, thus being heated to a supercritical state. The high-temperature, high-pressure supercritical CO2 enters the supercritical CO2 turbine 8, expands, and performs work, driving the generator 9 to generate electricity. After performing work, the CO2 flows sequentially through the regenerator 10 (releasing waste heat to preheat the CO2 from the compressor 12) and the condenser 11 to cool down before returning to the compressor 12, completing the cycle.

[0028] The heat recovery and supply unit includes three stages of heat recovery. First stage recovery: CO2, after performing work, preheats the working fluid in regenerator 10, and then exchanges heat with tap water in condenser 11 to produce domestic hot water. Second stage recovery: High-temperature O2 from Cl-H2O cryogenic reactor 4 is first cooled by exchanging heat with CO2 in first heat exchanger 13, and then enters O2 cooling heat recovery device 14 for further waste heat recovery (for heating). The cooled O2 is stored in O2 collection device 15. Third stage recovery: High-temperature H2 from V-Cl mesophilic reactor 3 is first cooled by exchanging heat with CO2 in second heat exchanger 5, and then enters H2 cooling heat recovery device 6 for further waste heat recovery (for heating). The cooled H2 is stored in H2 collection device 7.

[0029] Example 2: System variant (with heating as the primary output) In this embodiment, the system of Embodiment 1 is optimized for application scenarios with high heat energy demand, such as residential areas or industrial parks. Specifically, the capacity of the O2 cooling heat recovery device 14 and the H2 cooling heat recovery device 6 is increased, and they are designed to output heat media at different temperature levels (e.g., high-temperature hot water for industrial processes and low-temperature hot water for building heating). Simultaneously, the system can dynamically allocate the proportion of heat used for power generation and direct heating by adjusting the CO2 flow rate through the first heat exchanger 13 and the second heat exchanger 5. For example, at night or during off-peak electricity periods but with high heating demand, the heat used for heating CO2 for power generation can be appropriately reduced, while the heat directly supplied to users through the heat recovery devices can be increased. This achieves flexible adjustment of the combined heat and power (CHP) mode, maximizing the satisfaction of users' heat load needs.

[0030] Example 3: Method Example This embodiment describes a method for operating the system based on Embodiment 1, including the following steps: Step 1: Start the tower solar collector 1 and heat the heat transfer oil to the design temperature.

[0031] Step Two: Initiate the Vanadium-Chlorine Cycle. High-temperature heat transfer oil flows sequentially through V-Cl high-temperature reactor 2, V-Cl medium-temperature reactor 3, and Cl-H2O low-temperature reactor 4, providing heat for each stage of the reaction. VCl3 is introduced into V-Cl high-temperature reactor 2 to initiate the thermal decomposition reaction. The Cl2 generated in the reaction is passed into Cl-H2O low-temperature reactor 4 and reacts with water. The resulting HCl reacts with VCl2 from V-Cl high-temperature reactor 2 in V-Cl medium-temperature reactor 3, and the system stably produces H2 and O2.

[0032] Step 3: Start the supercritical CO2 power cycle. Start compressor 12, and the CO2 working fluid begins to circulate. High-temperature O2 and high-temperature H2 are used to heat the CO2 in stages in the first heat exchanger 13 and the second heat exchanger 5, respectively, until it reaches a supercritical state. The CO2 then enters the supercritical CO2 turbine 8, where it expands and performs work, driving generator 9 to generate electricity. A portion of the generated electricity is used to power the system's own equipment (such as compressor 12, control system, etc.), and the excess can be exported.

[0033] Step 4: Implement cascade heat recovery. The waste heat from the CO2 outlet of turbine 8 is recovered in regenerator 10 and condenser 11 for preheating the working fluid and producing domestic hot water. The waste heat from high-temperature O2 and high-temperature H2 is recovered through O2 cooling heat recovery device 14 and H2 cooling heat recovery device 6, supplying heating to users. The cooled O2 and H2 are stored in O2 collection device 15 and H2 collection device 7, respectively.

[0034] Example 4: Example of Material and Parameter Variation This embodiment illustrates the optional variations of certain parameters and materials within the scope of the claims. In the vanadium-chlorine cycle, the operating temperature of each reactor can be adjusted within a certain range according to catalyst activity and system optimization. For example, the temperature of the V-Cl high-temperature reactor 2 can be between 780-820K, the temperature of the V-Cl medium-temperature reactor 3 can be between 560-590K, and the temperature of the Cl-H2O low-temperature reactor 4 can be between 360-380K, all of which can achieve effective reactions. The solar thermal collection unit is not limited to a tower system; it can also employ trough, dish, or linear Fresnel concentrating thermal collection systems. The heating method in the heat recovery and supply unit is not limited to providing hot water; it can also provide hot air through an air heat exchanger. The pressure rating of the gas collection device (7,15) can be flexibly designed according to downstream applications, such as using medium-pressure storage for chemical raw material pipeline transportation or high-pressure storage for hydrogen refueling stations.

[0035] Example 5: Variation of heat collection method The difference between this embodiment and Embodiment 1 lies in the specific form of the solar thermal collector unit. In this embodiment, a parabolic trough solar thermal collector system is used instead of a tower-type solar thermal collector field 1. Multiple parabolic trough collectors are connected in series or parallel to form a collector field, and the heat transfer oil (or molten salt as the heat medium) in the collector tubes is heated to a high temperature. This high-temperature heat medium is transported through pipelines to the external jackets or coils of the V-Cl high-temperature reactor 2, the V-Cl medium-temperature reactor 3, and the Cl-H2O low-temperature reactor 4, respectively, to provide the required heat for each stage of the reaction. The parabolic trough collector system is more suitable for flat terrain, and the technology is relatively mature with controllable construction costs. This embodiment illustrates that the core of the invention lies in using solar thermal energy to drive a thermochemical cycle and coupling it with a supercritical CO2 power cycle. The specific form of solar focused thermal collection can be flexibly selected based on factors such as site and cost.

[0036] Example 6: Integrated Variant Example of a Power Cycle Heat Source This embodiment optimizes the heat source integration method of the supercritical CO2 power cycle unit based on Embodiment 1. The high-temperature heat transfer oil from the tower solar collector 1, after supplying heat to the V-Cl high-temperature reactor 2, V-Cl medium-temperature reactor 3, and Cl-H2O low-temperature reactor 4, still maintains a relatively high temperature. In this embodiment, a third heat exchanger (not shown in the figure) can be added after the second heat exchanger 5 in the heat transfer oil circulation pipeline. After flowing through all reactors, the high-temperature heat transfer oil first enters this third heat exchanger to exchange heat with the CO2 working fluid from the regenerator 10, supplementing the CO2 heating, before returning to the solar collector or entering the thermal storage system. This design integrates the residual heat from the solar collector into the heating process of the supercritical CO2 cycle, achieving deeper utilization of solar heat and further increasing the working fluid temperature entering the supercritical CO2 turbine 8, thereby improving power generation efficiency.

[0037] Example 7: Multi-mode operation control example This embodiment illustrates the flexible operation method of the system. The system can switch operating modes according to the alternation of day and night, seasonal changes, or user-side electric / heat load demands.

[0038] Full-day integrated mode (daytime): As described in Example 1, the solar thermal field operates at full power, and the system simultaneously performs efficient hydrogen production, oxygen production, power generation, and comprehensive three-stage heat recovery to maximize the comprehensive output of electricity, hydrogen, oxygen, hot water, and heating energy.

[0039] Power generation-focused mode: When grid electricity prices are at their peak or electricity demand is high, the CO2 flow rate through the first heat exchanger 13 and the second heat exchanger 5 can be appropriately increased by adjusting valves to maximize the utilization of the thermal energy of high-temperature H2 and O2 for power generation. At the same time, the distribution of heat transfer oil flow can be slightly adjusted to appropriately reduce the load on the hydrogen production reaction unit, so that the total system output is tilted towards electricity.

[0040] Focus on heating / domestic hot water mode: During winter nights or peak heating demand periods, the solar collectors cease operation. At this time, the hydrogen production unit can be maintained at a lower load or kept warm by relying on the heat storage system (such as high-temperature heat transfer oil or molten salt stored in the storage tank). The system's operation then shifts to utilizing the waste heat from stored materials and system circulation. Through the waste heat recovery section of the supercritical CO2 cycle (condenser 11) and the H2 / O2 cooling heat recovery device (6,14), domestic hot water and heating energy are continuously provided to users, achieving continuous 24 / 7 energy supply.

[0041] This embodiment illustrates that the system has good schedulability and adaptability to diverse needs.

[0042] Example 8: Co-production with downstream industries This embodiment demonstrates an extended application of the system. The outputs of the H2 collection device 7 and the O2 collection device 15 can be directly coupled with downstream industries to form a co-production system.

[0043] Scenario 1 (Chemical Cogeneration): The oxygen produced by the system is directly transported through pipelines to nearby gasification plants or steel mills, replacing or supplementing their traditional air separation oxygen production units, significantly reducing energy consumption and oxygen costs for downstream industries. Simultaneously, the generated hydrogen is supplied to nearby refining enterprises for hydrorefining processes, or used as a raw material for the production of synthetic ammonia, methanol, and other chemicals.

[0044] Scenario 2 (Transportation Energy): The H2 collection device 7 and its subsequent pipelines, compressors, and refueling machines are designed as a standard hydrogen refueling station hydrogen storage and refueling system. After purification and pressurization, the hydrogen produced by the system can directly provide refueling services for hydrogen fuel cell vehicles. Simultaneously, a portion of the electricity generated by the system can be used to power the compressors and charging stations at this hydrogen refueling station.

[0045] Scenario 3 (Energy Storage and Peak Shaving): When solar energy is abundant and the system generates surplus electricity, the excess electrical energy (produced by generator 9) can be used to drive a water electrolyzer to produce hydrogen. The hydrogen produced by water electrolysis can be stored together with the hydrogen produced by the thermochemical cycle of this system, realizing a "thermochemical + electrolysis" hybrid hydrogen production mode, thereby further improving the overall efficiency of solar energy conversion to hydrogen energy. The stored hydrogen can be used to generate electricity through fuel cells or hydrogen gas turbines during periods of no sunshine or peak electricity consumption, realizing cross-time dispatch of electricity and grid peak shaving.

[0046] This embodiment demonstrates the potential and significant socio-economic benefits of the system of the present invention as an "energy hub" deeply integrated with various industrial and energy application scenarios.

[0047] Example 9: Key Equipment, Materials, and Process Examples This embodiment provides specific implementation details of some key devices to further illustrate the feasibility of the present invention.

[0048] Reactor materials: The inner walls and heat transfer components of the V-Cl high-temperature reactor 2 (operating temperature approximately 798K) and the V-Cl medium-temperature reactor 3 (operating temperature approximately 573K) must withstand high-temperature corrosion under chloride environments and can be made of nickel-based alloys (such as Inconel 600 / 601) or special stainless steel. The Cl-H2O low-temperature reactor 4 (operating temperature approximately 373K), which processes aqueous solutions containing chloride ions, can be lined with titanium or fluorine.

[0049] Heat exchanger design: Since the working fluids on both sides of the first heat exchanger 13 (realizing O2-CO2 heat exchange) and the second heat exchanger 5 (realizing H2-CO2 heat exchange) are both gases and may have high pressure, in order to withstand the high pressure difference and achieve efficient and compact heat exchange, it is preferable to use a printed circuit board heat exchanger (PCHE) or a microchannel heat exchanger.

[0050] Heat recovery devices: H2 cooling heat recovery device 6 and O2 cooling heat recovery device 14 can be plate heat exchangers or shell and tube heat exchangers to transfer the heat of hydrogen or oxygen to an independent water circuit, which can be connected to the building's fan coil units (for cooling / heating) or floor heating system.

[0051] Working fluid and catalyst: Vanadium compounds (VCl2 / VCl3) in the V-Cl cycle can be supported on inert supports such as porous alumina or silicon carbide to increase the reaction contact area and improve reaction efficiency. The working fluid in the supercritical CO2 power cycle is high-purity carbon dioxide. A purification and separation device must be installed in the system to remove impurities and moisture that may be generated during the cycle, and to maintain the efficient and stable operation of the system.

[0052] Although the present invention has been described in detail through the foregoing embodiments, those skilled in the art can make changes and modifications to the implementation methods without departing from the core spirit of the invention. All such changes and modifications fall within the scope of protection defined by the appended claims.

Claims

1. A solar-powered integrated high-efficiency hydrogen production and energy supply system, characterized in that, include: Solar thermal collectors are used to capture and convert solar energy into thermal energy. A thermochemical hydrogen production unit, thermally connected to the solar collector unit, is used to drive at least one thermochemical reaction to produce hydrogen and oxygen using the thermal energy. The supercritical carbon dioxide power cycle unit is thermally connected to the thermochemical hydrogen production unit. It is used to recover the waste heat of the high-temperature products generated by the thermochemical hydrogen production unit and the residual heat energy of the solar thermal collector unit, and to generate electricity by doing work through the expansion of supercritical carbon dioxide. In addition, a heat recovery and supply unit is connected to the supercritical carbon dioxide power cycle unit and the thermochemical hydrogen production unit to recover the waste heat of the working fluid and products in the system and supply heat energy to the user end.

2. The solar-powered integrated high-efficiency hydrogen production and energy supply system according to claim 1, characterized in that: The thermochemical hydrogen production unit is a vanadium-chlorine cycle hydrogen production system, which includes a high-temperature reactor, a medium-temperature reactor and a low-temperature reactor connected in sequence. The high-temperature reactor is used to thermally decompose vanadium trichloride at a first temperature to generate chlorine gas and vanadium dichloride. The low-temperature reactor is used to react the chlorine gas with water at a second temperature to produce hydrogen chloride and oxygen. The intermediate-temperature reactor is used to react the vanadium dichloride with the hydrogen chloride at a third temperature to generate hydrogen gas and regenerated vanadium trichloride, the regenerated vanadium trichloride being returned to the high-temperature reactor; Wherein, the first temperature is higher than the third temperature, and the third temperature is higher than the second temperature.

3. The solar-powered integrated high-efficiency hydrogen production and energy supply system according to claim 2, characterized in that, The first temperature is 798±20K, the second temperature is 373±10K, and the third temperature is 573±20K.

4. The solar-powered integrated high-efficiency hydrogen production and energy supply system according to claim 1, characterized in that, The supercritical carbon dioxide power cycle unit includes a compressor, a regenerator, at least one first-stage heater, a turbine, and a condenser connected in sequence by pipelines. The carbon dioxide working fluid from the compressor outlet flows sequentially through the cold side of the regenerator and the first stage heater, and is heated to a supercritical state before entering the turbine to expand and do work. After performing work, the carbon dioxide working fluid flows sequentially through the hot side of the regenerator and the condenser to cool down before returning to the compressor.

5. The solar-powered integrated high-efficiency hydrogen production and energy supply system according to claim 4, characterized in that, The at least one first-stage heater includes a first heat exchanger and a second heat exchanger; The first heat exchanger is configured to exchange heat between the carbon dioxide working fluid and the high-temperature oxygen produced by the thermochemical hydrogen production unit. The second heat exchanger is configured to exchange heat between the carbon dioxide working fluid and the high-temperature hydrogen produced by the thermochemical hydrogen production unit.

6. The solar-powered integrated high-efficiency hydrogen production and energy supply system according to claim 5, characterized in that, The heat recovery and supply unit includes: The first-stage heat recovery module, including the regenerator and condenser, is used to recover the waste heat of the carbon dioxide working fluid after it has done work in the supercritical carbon dioxide power cycle unit, and to preheat the working fluid and / or prepare domestic hot water. The second-stage heat recovery module is connected to the oxygen output terminal of the thermochemical hydrogen production unit and is used to recover the waste heat of the oxygen and provide heating for the user end. The third-stage heat recovery module is connected to the hydrogen output terminal of the thermochemical hydrogen production unit and is used to recover the waste heat of the hydrogen and provide heating for the user.

7. The solar-powered integrated high-efficiency hydrogen production and energy supply system according to claim 6, characterized in that, It also includes a gas collection device, with an oxygen collection device and a hydrogen collection device connected downstream of the second-stage heat recovery module and the third-stage heat recovery module, respectively.

8. An operation method for a solar-powered integrated high-efficiency hydrogen production and energy supply system based on any one of claims 1-7, characterized in that, Includes the following steps: S1: Utilize solar thermal collectors to capture solar energy and convert it into thermal energy; S2: The thermal energy is transferred to the thermochemical hydrogen production unit to drive a multi-stage thermochemical reaction to continuously produce hydrogen and oxygen. S3: The high-temperature hydrogen and high-temperature oxygen produced by the thermochemical hydrogen production unit, as well as the residual heat energy of the solar thermal collector unit, are used to heat the carbon dioxide working fluid in the supercritical carbon dioxide power cycle unit. S4: The carbon dioxide working fluid, heated to a supercritical state, expands and does work, driving the generator to generate electricity; S5: Perform cascaded waste heat recovery on the carbon dioxide working fluid after work is done, as well as the high-temperature hydrogen and high-temperature oxygen generated in step S2. The recovered heat energy is used for internal system preheating and / or to supply domestic hot water and heating to users.

9. The operating method according to claim 8, characterized in that, Step S2 specifically includes: S21: In a high-temperature reactor, the thermal energy is used to thermally decompose vanadium trichloride into chlorine gas and vanadium dichloride. S22: In a low-temperature reactor, the chlorine gas reacts with water to produce hydrogen chloride and oxygen; S23: In a medium-temperature reactor, the vanadium dichloride reacts with the hydrogen chloride to generate hydrogen gas and regenerated vanadium trichloride. S24: Return the regenerated vanadium trichloride to step S21 for recycling.

10. The operating method according to claim 9, characterized in that, In step S5, the cascade waste heat recovery includes: The carbon dioxide working fluid, after performing work, is used to preheat the carbon dioxide working fluid that is about to enter the heating process in the regenerator, and then it exchanges heat with tap water in the condenser to produce domestic hot water. The high-temperature oxygen is sequentially exchanged with carbon dioxide working fluid and user-end heating medium before being cooled and stored. The high-temperature hydrogen gas is sequentially exchanged with carbon dioxide working fluid and user-end heating medium before being cooled and stored.

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