Copper-chlorine cycle hydrogen / power cogeneration system and method using complementary coupling of solar energy and natural gas

Abstract

The present application provides a copper-chlorine cycle hydrogen / electricity cogeneration system and method that complementarily couples solar energy and natural gas, including a concentrating assembly for enhancing solar radiation intensity; a methane oxygen-enriched combustion high-temperature photovoltaic power generation device for utilizing natural gas to achieve oxygen-enriched combustion and utilizing the radiation energy generated by the first-stage high-temperature flue gas produced after combustion to generate electricity; a supercritical carbon dioxide Brayton cycle device for utilizing the heat energy contained in the second-stage high-temperature flue gas to drive power cycle power generation; and a thermochemical reaction device for utilizing the heat energy contained in the third, fourth, and fifth-stage high-temperature flue gas to drive each step of the thermochemical reaction. The system energy sources are solar radiation and natural gas, and the outputs are hydrogen and electricity. The present application complements low-grade solar energy with natural gas, improving the energy quality, and based on the principle of energy quality matching, utilizes different qualities of electricity / heat energy to be supplied to the thermochemical cycle in stages to produce hydrogen, achieving complementary coupling of different qualities of energy on the basis of energy cascade conversion, and providing an efficient solar hydrogen and electricity cogeneration approach.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy production, and in particular relates to a copper-chlorine cycle hydrogen / power cogeneration system and method using complementary coupling of solar energy and natural gas. Background Art

[0002] Due to its cleanliness, widespread availability, and enormous energy potential, solar energy is considered one of the most promising green energy sources. Hydrogen, a clean secondary energy source that can be derived from water decomposition, is an important energy storage medium. However, in the process of solar energy utilization, low-grade solar energy cannot be effectively utilized, making it difficult to improve solar energy utilization and conversion efficiency. Furthermore, solar energy utilization is unstable due to weather conditions. Therefore, combining low-grade solar energy with natural gas can effectively improve energy quality, theoretically producing high-temperature flue gas exceeding 2000°C. However, a single method for fully and efficiently utilizing high-grade energy remains lacking. Therefore, a cascaded energy conversion and utilization approach is a scientific and effective approach. For high-temperature energy, thermophotovoltaic power generation is an emerging technology that directly converts high-grade thermal energy into electricity. The emitter is heated to temperatures exceeding 1400°C, generating radiant energy for photovoltaic power generation. Furthermore, the supercritical CO2 Brayton cycle offers advantages such as high efficiency, flexibility, environmental friendliness, and cost-effectiveness. Because it can accommodate a wide range of heat source temperatures (200-850°C) and, through scientifically matching system parameters, achieves relatively high operating efficiency compared to other heat-to-power conversion devices at the same temperature, it has broad application prospects in coal-fired power generation, solar thermal power generation, nuclear power, and waste heat power generation. By leveraging the strengths and weaknesses of different technologies, we can achieve cascaded energy conversion and improve energy utilization efficiency.

[0003] For hydrogen production, thermochemical water decomposition is a clean and efficient method of hydrogen production. It is a thermochemical indirect water decomposition cycle constructed through the redox reaction of oxygen-carrying materials. Compared with the common thermochemical cycle hydrogen production (usually requiring a temperature above 1000°C), the maximum temperature required in the copper-chlorine cycle is only 530°C, which greatly reduces the temperature of water decomposition, and there is no greenhouse gas emission in the cycle. The four-step copper-chlorine cycle includes: pyrolysis reaction, hydrolysis reaction, drying reaction and electrolysis reaction. Among them, pyrolysis, hydrolysis and drying reactions require thermal energy of different grades, and electrolysis reaction requires electrical energy. It can be matched with the complementary cascade conversion and utilization of solar energy and natural gas (power generation and heat supply), realizing the complementary coupling of energy of different qualities and providing an efficient solar hydrogen and electricity cogeneration approach. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present application aims to provide a copper-chlorine cycle hydrogen / electricity cogeneration system and method that complements solar energy and natural gas, complementing low-grade solar energy and natural gas to improve energy quality, and based on the principle of energy quality matching, through different energy conversion forms, effectively utilize energy in a graded manner and match-coupled copper-chlorine cycle to efficiently output hydrogen and electricity, greatly improving energy utilization efficiency.

[0005] On the one hand, the present application proposes a copper-chlorine cycle hydrogen / power cogeneration system with complementary coupling of solar energy and natural gas, which includes a concentrating component, a methane oxygen-enriched combustion high-temperature photovoltaic power generation device, a supercritical CO2 Brayton cycle device, and a thermochemical reaction device;

[0006] The system comprises a gas pipeline which is sequentially connected to a tubular receiver, a combustion chamber, a heat exchanger, a pyrolysis reaction chamber, a hydrolysis reaction chamber and a drying reaction chamber;

[0007] The tubular receiver and combustion chamber are components of the methane oxygen-enriched combustion high-temperature photovoltaic power generation device. The gas pipeline inputs oxygen-enriched air to the tubular receiver, which absorbs sunlight focused by the concentrating component and preheats the oxygen-enriched air. The preheated oxygen-enriched air is then fed into the combustion chamber together with natural gas for combustion. The combustion chamber produces first-stage high-temperature flue gas, which generates radiation energy through the emitter. The methane oxygen-enriched combustion high-temperature photovoltaic power generation device uses the radiation energy to generate photovoltaic power, and the combustion chamber discharges second-stage high-temperature flue gas.

[0008] The heat exchanger is a component of the supercritical CO2 Brayton cycle device. It receives the second-stage high-temperature flue gas generated by the combustion chamber through a pipeline. The supercritical CO2 Brayton cycle device uses the heat contained in the second-stage high-temperature flue gas to drive the supercritical CO2 Brayton cycle to generate electricity. The heat exchanger supplies the third-stage high-temperature flue gas after heat exchange to the pyrolysis reaction chamber.

[0009] The pyrolysis reaction chamber, hydrolysis reaction chamber and drying reaction chamber utilize the heat energy contained in the high-temperature flue gas to react step by step, and they are all components of the thermochemical circulation device. The entire thermochemical circulation device utilizes the heat energy contained in the high-temperature flue gas and the electricity of the methane oxygen-enriched combustion high-temperature photovoltaic power generation device to realize the copper-chlorine cycle and produce hydrogen and oxygen.

[0010] On the other hand, the present application also proposes a copper-chlorine cycle hydrogen / power cogeneration method using complementary coupling of solar energy and natural gas, comprising the following steps: oxygen-enriched air is preheated by solar energy in a tubular receiver and then introduced into a combustion chamber together with natural gas for combustion, generating a first-stage high-temperature flue gas having a temperature of 2000-2500°C; the radiant energy contained in the first-stage high-temperature flue gas is used by the methane oxygen-enriched combustion high-temperature photovoltaic power generation device to generate thermal photovoltaic power, converting the radiant energy into a second-stage high-temperature flue gas having a temperature of 850-1000°C, which is then introduced into a heat exchanger;

[0011] The supercritical CO2 Brayton cycle device uses the heat energy contained in the second-stage high-temperature flue gas in the heat exchanger to drive the supercritical CO2 Brayton cycle to generate electricity. The third-stage high-temperature flue gas with a discharge temperature of 530-680°C from the heat exchanger is passed into the pyrolysis reaction chamber;

[0012] The pyrolysis reaction chamber uses the heat energy contained in the third-stage high-temperature flue gas to drive the pyrolysis reaction, converting it into the fourth-stage high-temperature flue gas with a temperature of 400-460°C, which is then passed into the hydrolysis reaction chamber; the hydrolysis reaction chamber uses the heat energy contained in the fourth-stage high-temperature flue gas to drive the hydrolysis reaction, converting it into the fifth-stage high-temperature flue gas with a temperature of 130-200°C, which is then passed into the drying reaction chamber; the drying reaction chamber uses the heat energy contained in the fifth-stage high-temperature flue gas to drive the drying reaction, converting it into low-temperature flue gas for discharge; the electrolysis reaction chamber of the thermochemical reaction device uses part of the electrical energy stored in the battery to carry out an electrolysis reaction to produce hydrogen, and the prepared hydrogen is stored in the hydrogen storage tank.

[0013] The system and method proposed in this application have the following advantages or beneficial effects: low-grade solar energy and natural gas are complemented, and a first-stage high-temperature flue gas with a temperature of 2000-2500°C is obtained through oxygen-enriched combustion, which effectively improves the energy grade; based on the energy quality matching principle, the first-stage high-temperature flue gas with a temperature of 2000-2500°C is used for high-temperature thermal photovoltaic power generation, and the second-stage high-temperature flue gas with a temperature of 850-1000°C is used to drive supercritical CO2 Brayton cycle power generation; different qualities of electric / thermal energy are supplied to the thermochemical cycle in stages to produce hydrogen, and complementary coupling of different qualities is achieved on the basis of energy ladder conversion, and the third, fourth and fifth-stage high-temperature flue gases with successively lower temperatures are used to drive pyrolysis and hydrolysis in the thermochemical cycle respectively. , drying reaction, and using the electricity generated by thermal photovoltaics to drive the electrolysis reaction in the thermochemical cycle, which constitutes a complete four-step copper-chlorine cycle for hydrogen production; the oxygen produced by the pyrolysis reaction can be used to provide raw materials for oxygen-enriched combustion. The present application balances the instability of solar energy by regulating the oxygen content in the oxygen-enriched air to ensure the self-sustaining operation of the system day and night; the heat generated by the power generation of photovoltaic cells is used to preheat the water required for the thermochemical cycle, which can not only avoid the temperature rise of the photovoltaic cells due to a large amount of radiation energy, but also help to improve the energy utilization efficiency of the system; the present application provides an efficient solar hydrogen cogeneration approach, the system energy sources are solar radiation and natural gas, and the outputs are hydrogen and electricity; the secondary energy utilization efficiency of the present application can exceed 60%, and the electrical efficiency can exceed 52%. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of a copper-chlorine cycle hydrogen / power cogeneration system structure using complementary coupling of solar energy and natural gas according to one embodiment of the present application;

[0015] Among them, 1- focusing assembly, 2- tubular receiver, 3- combustion chamber, 4- transmitter, 5- filter, 6- photovoltaic cell, 7- photovoltaic cell waste heat utilization device, 8- heat exchanger, 9- turbine, 10- generator, 11- high temperature regenerator, 12- low temperature regenerator, 13- precooler, 14- main compressor, 15- auxiliary compressor, 16- pyrolysis reaction chamber, 17- hydrolysis reaction chamber, 18- drying reaction chamber, 19- electrolysis reaction chamber, 20- hydrogen storage tank, 21- oxygen storage tank, 22- battery. DETAILED DESCRIPTION

[0016] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0017] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present invention and are intended to be used to explain the inventive concept. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0018] Unless otherwise clearly stipulated and limited, the terms "high temperature", "low temperature", "high pressure", "low pressure", etc. used in descriptions are only used to describe relative characteristics, and do not indicate or imply that the technical characteristics referred to must have specific indicators.

[0019] Unless otherwise specified or limited, the terms "connected" and "connection" used in the description should be understood broadly. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, indirect connection through an intermediate medium; internal communication between two elements, or interaction between two elements. Those skilled in the art will understand the specific meanings of the above terms in the embodiments based on specific circumstances.

[0020] The embodiments of the present application provide a copper-chlorine cycle hydrogen / power cogeneration system that complementarily couples solar energy and natural gas, and a method for hydrogen and power cogeneration using the system.

[0021] See also Figure 1In a specific embodiment of the present application, a copper-chlorine cycle hydrogen / power cogeneration system with complementary coupling of solar energy and natural gas is provided, including a concentrating component 1, a methane oxygen-enriched combustion high-temperature photovoltaic power generation device, a supercritical CO2 Brayton cycle device and a thermochemical reaction device; wherein the concentrating component 1 is mainly used to concentrate sunlight onto a tubular receiver 2 of the methane oxygen-enriched combustion high-temperature photovoltaic power generation device, thereby enhancing the intensity of solar radiation and making more efficient use of solar energy. On the one hand, the methane oxygen-enriched combustion high-temperature photovoltaic power generation device uses solar energy to preheat the oxygen-enriched air, and on the other hand, uses the preheated oxygen-enriched air to burn with natural gas to generate high-temperature flue gas to drive the subsequent supercritical CO2 Brayton cycle device and the thermochemical reaction device, and it also uses the radiation energy of the high-temperature flue gas to generate photovoltaic power for the photovoltaic power generation device; the supercritical CO2 Brayton cycle device uses the high-temperature flue gas generated by the methane oxygen-enriched combustion high-temperature photovoltaic power generation device to drive the supercritical CO2 Brayton cycle power generation; the thermochemical reaction device uses the heat energy contained in the high-temperature flue gas after heat exchange of the supercritical CO2 Brayton cycle device and the electrical energy of the methane oxygen-enriched combustion high-temperature photovoltaic power generation device to realize the copper-chlorine cycle and produce hydrogen and oxygen, of which the oxygen can be further supplied to the methane oxygen-enriched combustion high-temperature photovoltaic power generation device to regulate the oxygen content in the oxygen-enriched air. The system's energy sources are solar radiation and natural gas, and its outputs are hydrogen and electricity. The systems work together to complement low-grade solar energy with natural gas, effectively improving the energy quality through oxygen-enriched combustion. Based on the principle of energy quality matching, high-temperature flue gases at different temperatures are used for high-temperature thermal photovoltaic power generation, driving supercritical CO2 Brayton cycle power generation, and thermochemical cycle production of hydrogen, achieving complementary coupling of different qualities based on energy cascade conversion. This system fully utilizes the quality of energy and has extremely high secondary energy utilization efficiency.

[0022] It should be noted that the system of the present invention has an air / flue gas pipeline (gas line) for transferring heat, which is connected in sequence to the tubular receiver 2 and combustion chamber 3 of the methane oxygen-enriched combustion high-temperature photovoltaic power generation device, the heat exchanger 8 of the supercritical CO2 Brayton cycle device, and the pyrolysis reaction chamber 16, hydrolysis reaction chamber 17 and drying reaction chamber 18 of the thermochemical reaction device, thereby realizing the cascade conversion and utilization of high-temperature flue gas energy at different temperatures.

[0023] In one embodiment of the present invention, the concentrating assembly 1 concentrates sunlight onto the tubular receiver 2 to enhance the solar radiation intensity. Preferably, the concentrating assembly 1 is a point-focusing Fresnel concentrating assembly, which is a mature and inexpensive product.

[0024] like Figure 1As shown, in one embodiment of the present invention, the methane oxygen-enriched combustion high-temperature photovoltaic power generation device includes a tubular receiver 2, a combustion chamber 3, a transmitter 4, a filter 5, a photovoltaic cell 6, and a photovoltaic cell waste heat utilization device 7. A photothermal absorber is fixed within the tubular receiver 2, absorbing sunlight focused by the concentrating assembly 1 and converting it into thermal energy. This absorber preheats the oxygen-enriched air entering the tubular receiver 2, generating oxygen-enriched air at a temperature of 600-700°C. Natural gas and the preheated oxygen-enriched air are then fed into the combustion chamber 3 for oxygen-enriched combustion, generating a first-stage high-temperature flue gas at a temperature of 2000-2500°C. The first-stage high-temperature flue gas generates radiation energy through the emitter 4, and the radiation energy selectively passes through the filter 5 and is absorbed by the photovoltaic cell 6 to generate electrical energy. The radiation energy that does not match the photovoltaic cell returns to the combustion chamber 3. Then the first-stage high-temperature flue gas is converted into a second-stage high-temperature flue gas with a temperature of 850-1000°C and discharged from the combustion chamber 3 to supply the heat exchanger 8 of the supercritical CO2 Brayton cycle device; the photovoltaic cell waste heat utilization device 7 recovers the heat energy of the photovoltaic cell 6 to preheat water, and obtains hot water with a temperature of 40-60°C as the raw material for the pyrolysis reaction in the thermochemical cycle, thereby improving the energy utilization efficiency and avoiding the temperature rise of the photovoltaic cell caused by the large amount of radiation energy. Preferably, the tubular receiver 2 is provided with an inlet for air, an inlet for oxygen, and an outlet for preheated, oxygen-enriched air. The inlet for oxygen is connected to the outlet of the oxygen storage tank 21. The combustion chamber 3 is provided with an inlet for oxygen-enriched air and an outlet for exhausting the second-stage high-temperature flue gas. The inlet for oxygen-enriched air is connected to the oxygen-enriched air outlet of the tubular receiver 2. The photovoltaic cell waste heat utilization device 7 is provided with an inlet for cold water and an outlet for hot water. Preferably, the photovoltaic cell 6 is a gallium arsenide (GaAs) photovoltaic cell with a cutoff wavelength of 900 nm. This type of photovoltaic cell has high photoelectric conversion efficiency, can withstand high temperatures and high-concentration light, and better meets system requirements.

[0025] like Figure 1As shown, in one embodiment of the present invention, the supercritical CO2 Brayton cycle device includes a connected heat exchanger 8, a turbine 9, a generator 10, a high-temperature regenerator 11, a low-temperature regenerator 12, a precooler 13, a main compressor 14 and an auxiliary compressor 15. The heat exchanger 8 uses the heat contained in the second-stage high-temperature flue gas to drive the supercritical CO2 Brayton cycle to generate electricity. After heat exchange, the second-stage high-temperature flue gas is converted into a third-stage high-temperature flue gas with a temperature of 530-680°C and supplied to the pyrolysis reaction chamber 16 of the thermochemical cycle device; inside the supercritical CO2 Brayton cycle, the high-pressure CO2 first absorbs the heat from the second-stage high-temperature flue gas in the heat exchanger 8 and becomes a high-temperature and high-pressure working fluid (600-850°C, 25MPa); the high-temperature and high-pressure working fluid enters the turbine 9 to generate electricity and becomes a low-pressure working fluid, which outputs electrical energy through the generator 10; the low-pressure working fluid enters The hot side of the high-temperature regenerator 11 releases heat, and then enters the low-temperature regenerator 12 to continue releasing heat; the working fluid is divided into two streams at the hot side outlet of the low-temperature regenerator 12, one stream enters the hot side of the precooler 13 to continue releasing heat, and then the low-temperature and low-pressure working fluid (32°C, 7.38MPa) enters the main compressor 14 for supercharging, and then enters the cold side of the low-temperature regenerator 12 to absorb heat; the other stream enters the auxiliary compressor 15 for supercharging, and the supercharged working fluid merges with the cold side outlet stream of the low-temperature regenerator 12, and together enters the cold side of the high-temperature regenerator 11 to absorb heat, and finally enters the heat exchanger 8 to absorb heat, forming a complete supercritical CO2 Brayton cycle. Preferably, the heat exchanger 8 is provided with an inlet for the second-stage high-temperature flue gas, an outlet for discharging the third-stage high-temperature flue gas, an inlet for the low-temperature supercritical working fluid, and an outlet for discharging the high-temperature supercritical working fluid. The inlet for the second-stage high-temperature flue gas is connected to the outlet of the combustion chamber 3; the precooler 13 is provided with an inlet for cold water and an outlet for discharging hot water. Preferably, the temperature of the high-temperature and high-pressure working fluid at the inlet of the turbine 9 is controlled to 850°C, the minimum pressure and the maximum pressure in the supercritical CO2 Brayton cycle are set to 7.38MPa and 25MPa respectively, and the cycle efficiency can exceed 60%.

[0026] like Figure 1 As shown, in one embodiment of the present invention, the thermochemical reaction device includes a pyrolysis reaction chamber 16 , a hydrolysis reaction chamber 17 , a drying reaction chamber 18 and an electrolysis reaction chamber 19 .

[0027] The pyrolysis reaction chamber 16 utilizes the heat contained in the third-stage high-temperature flue gas to promote the pyrolysis reaction, so that the temperature in the pyrolysis reaction chamber 16 is maintained at 500-530°C. After heat exchange, the third-stage high-temperature flue gas is converted into a fourth-stage high-temperature flue gas with a temperature of 400-460°C and supplied to the hydrolysis reaction chamber 17; the chemical reaction equation of the pyrolysis reaction is Cu2OCl2(s)→2CuCl(l)+0.5O2(g).

[0028] The hydrolysis reaction chamber 17 utilizes the heat contained in the fourth-stage high-temperature flue gas to promote the hydrolysis reaction, so that the temperature in the hydrolysis reaction chamber is maintained at 370-400°C. After heat exchange, the fourth-stage high-temperature flue gas is converted into the fifth-stage high-temperature flue gas with a temperature of 130-200°C and supplied to the drying reaction chamber (18); the chemical reaction equation of the hydrolysis reaction is 2CuCl2(s)+H2O(g)→2HCl(g)+Cu2OCl2(s), and the product HCl gas is supplied to the electrolysis reaction chamber 19 as a raw material for the electrolysis reaction.

[0029] The drying reaction chamber 18 uses the heat contained in the fifth-stage high-temperature flue gas to promote the drying reaction, evaporate the water in the CuCl2 solution, and form solid CuCl2, so that the temperature in the drying reaction chamber is maintained at 100-130°C. After heat exchange, the fifth-stage high-temperature flue gas is converted into low-temperature flue gas and discharged.

[0030] The electrolysis reaction chamber 19 utilizes part of the electricity generated by the photovoltaic cells stored in the storage battery 22 to promote the electrolysis reaction. The chemical reaction equation is 2CuCl(aq)+2HCl(g)→H2(g)+2CuCl2(aq).

[0031] The above-mentioned thermochemical reactions constitute a complete cycle, namely a four-step copper-chlorine cycle, and the net reaction is the decomposition of water into hydrogen and oxygen. The thermochemical reaction device sequentially utilizes the heat energy contained in the third, fourth, and fifth stage high-temperature flue gases and part of the electricity generated by the photovoltaic cells to meet their different reaction temperature conditions and required energy types, which is conducive to the full progress of the reaction and enables the energy to be effectively utilized in a graded manner. Preferably, the third-stage high-temperature flue gas inlet of the pyrolysis reaction chamber 16 is connected to the high-temperature flue gas outlet of the heat exchanger 8, the fourth-stage high-temperature flue gas inlet of the hydrolysis reaction chamber 17 is connected to the high-temperature flue gas outlet of the pyrolysis reaction chamber 16, and the fifth-stage high-temperature flue gas inlet of the drying reaction chamber 18 is connected to the high-temperature flue gas outlet of the hydrolysis reaction chamber 17.

[0032] In a specific embodiment, the system further includes a solid-liquid material transport system, through which the solid Cu2OCl2 and HCl gas produced by the reaction in the hydrolysis reaction chamber 17 are transported to the pyrolysis reaction chamber 16 and the electrolysis reaction chamber 19, respectively. The liquid CuCl2 produced by the reaction in the pyrolysis reaction chamber 16 is transported to the electrolysis reaction chamber 19. The CuCl2 solution produced by the reaction in the electrolysis reaction chamber 19 is transported to the drying reaction chamber 18. The solid CuCl2 produced by the reaction in the drying reaction chamber 18 is transported to the hydrolysis reaction chamber 17. The solid-liquid material transport system recovers and transports the reusable solid and liquid products produced in each device, thereby realizing the recycling of materials in the hydrogen production system, reducing production costs, and avoiding environmental pollution.

[0033] like Figure 1As shown, in an optional embodiment, the system of the present invention further includes a hydrogen storage tank 20, an oxygen storage tank 21 and a battery 22, wherein the hydrogen storage tank 20 is connected to the hydrogen outlet of the electrolysis reaction chamber 19, and the oxygen storage tank 21 is connected to the oxygen outlet of the pyrolysis reaction chamber 16; the battery 22 is used to store the electricity generated by the photovoltaic cell 6 and is connected to the photovoltaic cell 6.

[0034] The embodiment of the present application also provides a method for copper-chlorine cycle hydrogen / electricity cogeneration by complementary coupling of solar energy and natural gas, comprising the following steps: oxygen-enriched air is preheated by solar energy in a tubular receiver 2 and heated to 600-700°C, and then introduced into a combustion chamber 3 together with natural gas for combustion, generating a first-stage high-temperature flue gas with a temperature of 2000-2500°C; the radiation energy contained in the first-stage high-temperature flue gas with a temperature of 2000-2500°C is used by the methane oxygen-enriched combustion high-temperature photovoltaic power generation device to perform thermal photovoltaic power generation, and the second-stage high-temperature flue gas with a temperature of 850-1000°C is converted into the second-stage high-temperature flue gas introduced into the supercritical CO2 Brayton cycle device, and the generated electricity is stored in the battery 22; the supercritical CO2 Brayton cycle device uses the heat energy contained in the second-stage high-temperature flue gas with a temperature of 850-1000°C to drive the supercritical CO2 Brayton cycle power generation, produce electricity for supplying the power grid, and convert it into a second-stage high-temperature flue gas with a temperature of 530-680°C. The third-stage high-temperature flue gas is introduced into the pyrolysis reaction chamber 16, so that the temperature of the high-temperature and high-pressure working medium at the inlet of the turbine 9 in the cycle is about 850°C; the heat energy contained in the third-stage high-temperature flue gas with a temperature of 530-680°C is used by the pyrolysis reaction chamber 16 to drive the pyrolysis reaction, and the heat energy is converted into the fourth-stage high-temperature flue gas with a temperature of 400-460°C, which is introduced into the hydrolysis reaction chamber 17, so that the temperature in the pyrolysis reaction chamber 16 is maintained at 500-530°C; the heat energy contained in the third-stage high-temperature flue gas with a temperature of 400-460°C is used by the hydrolysis reaction chamber 17 to drive the pyrolysis reaction. The heat energy contained in the fourth-stage high-temperature flue gas at a temperature of 0 to 460°C drives the hydrolysis reaction, converts it into the fifth-stage high-temperature flue gas at a temperature of 130 to 200°C, and enters the drying reaction chamber 18, so that the temperature in the hydrolysis reaction chamber 17 is maintained at 370 to 400°C; the heat energy contained in the fifth-stage high-temperature flue gas at a temperature of 130 to 200°C is used by the drying reaction chamber 18 to drive the drying reaction, converts it into low-temperature flue gas and discharges it, so that the temperature in the drying reaction chamber 18 is maintained at 100 to 130°C.

[0035] In a specific embodiment, the method further includes the following steps: the liquid CuCl product of the pyrolysis reaction is supplied to the electrolysis reaction chamber 19 as a raw material for the electrolysis reaction, and the product oxygen leaves the circulation; the solid Cu2OCl2 product of the hydrolysis reaction is supplied to the pyrolysis reaction chamber 16 as a raw material for the pyrolysis reaction; the solid CuCl2 product of the drying reaction is supplied to the hydrolysis reaction chamber 17 as a product of the hydrolysis reaction; the CuCl2 solution product of the electrolysis reaction is supplied to the drying reaction chamber 18 as a raw material for the drying reaction, and the product hydrogen leaves the circulation.

[0036] In a specific embodiment, the method further includes the following steps: using a portion of the electrical energy stored in the battery 22 to perform an electrolysis reaction in the electrolysis reaction chamber 19 to produce hydrogen, and the prepared hydrogen is stored in the hydrogen storage tank 20; the oxygen produced by the reaction in the pyrolysis reaction chamber 16 is stored in the oxygen storage tank 21, and part of it is introduced into the tubular receiver 2 to mix with air to form oxygen-enriched air; by regulating the ratio of air and oxygen entering the tubular receiver 2, that is, regulating the oxygen content in the oxygen-enriched air, the instability of solar energy is balanced to ensure stable operation of the system day and night.

[0037] In a specific embodiment, the four-step copper-chlorine cycle requires 349.96 kJ / (mol H2) of thermal energy and 57.76 kJ / (mol H2) of electrical energy. Excess preheated hot water is introduced to ensure that the reaction proceeds fully. To ensure safety, the temperature of the oxygen-enriched air preheated by concentrated solar energy does not exceed 700°C, and the natural gas feed power is 15 kW. The methane oxygen-enriched combustion high-temperature photovoltaic power generation device generates 8.19 kW of electricity, the supercritical CO2 Brayton cycle device generates 0.57 kW of electricity, the thermochemical cycle consumes 0.72 kW of electricity, and the hydrogen production power is 3.16 kW. The system's secondary energy utilization efficiency is 61.26%, which is equivalent to an electrical efficiency of 52.95%. It can be seen that the system and method of the present invention complement low-grade solar energy and natural gas, improving energy quality. Based on the principle of energy quality matching, different qualities of electricity / heat energy are supplied to the thermochemical cycle in stages to produce hydrogen, achieving complementary coupling of different qualities of energy based on energy cascade conversion, and providing an efficient solar hydrogen cogeneration approach.

[0038] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A copper-chlorine cycle hydrogen / power cogeneration system with complementary coupling of solar energy and natural gas, characterized in that: It includes a concentrating assembly (1), a methane oxygen-enriched combustion high-temperature photovoltaic power generation device, a supercritical CO2 Brayton cycle device, and a thermochemical reaction device; The system comprises a gas pipeline which is sequentially connected to a tubular receiver (2), a combustion chamber (3), a heat exchanger (8), a pyrolysis reaction chamber (16), a hydrolysis reaction chamber (17) and a drying reaction chamber (18); The tubular receiver (2) and the combustion chamber (3) are components of the methane oxygen-enriched combustion high-temperature photovoltaic power generation device. The gas pipeline inputs oxygen-enriched air to the tubular receiver (2). The tubular receiver (2) absorbs sunlight focused by the focusing component (1) and preheats the oxygen-enriched air. The preheated oxygen-enriched air and natural gas are input together into the combustion chamber (3) for combustion. The combustion chamber (3) generates first-stage high-temperature flue gas which generates radiation energy through the emitter (4). The methane oxygen-enriched combustion high-temperature photovoltaic power generation device uses the radiation energy to generate photovoltaic power. The combustion chamber (3) discharges second-stage high-temperature flue gas. The heat exchanger (8) is a component of the supercritical CO2 Brayton cycle device, which receives the second-stage high-temperature flue gas generated by the combustion chamber (3) through a pipeline; the supercritical CO2 Brayton cycle device uses the heat contained in the second-stage high-temperature flue gas to drive the supercritical CO2 Brayton cycle to generate electricity, and the heat exchanger (8) supplies the third-stage high-temperature flue gas after heat exchange to the pyrolysis reaction chamber (16); The pyrolysis reaction chamber (16), the hydrolysis reaction chamber (17) and the drying reaction chamber (18) utilize the heat energy contained in the high-temperature flue gas to react step by step, and they are all components of the thermochemical cycle device. The entire thermochemical cycle device utilizes the heat energy contained in the high-temperature flue gas and the electricity of the methane oxygen-enriched combustion high-temperature photovoltaic power generation device to realize the copper-chlorine cycle and generate hydrogen and oxygen; The supercritical CO2 Brayton cycle device comprises a connected heat exchanger (8), a turbine (9), a generator (10), a high-temperature regenerator (11), a low-temperature regenerator (12), a precooler (13), a main compressor (14) and an auxiliary compressor (15); inside the supercritical CO2 Brayton cycle device, high-pressure CO2 first absorbs heat from the second-stage high-temperature flue gas in the heat exchanger (8) to become a high-temperature and high-pressure working fluid; the high-temperature and high-pressure working fluid enters the turbine (9) to generate power and becomes a low-pressure working fluid, which outputs electrical energy through the generator (10); the low-pressure working fluid enters the high-temperature regenerator (11) The hot side releases heat and then enters the low-temperature regenerator (12) to continue releasing heat; the working fluid is divided into two streams at the hot side outlet of the low-temperature regenerator (12), one stream enters the hot side of the precooler (13) to continue releasing heat, and then the low-temperature and low-pressure working fluid enters the main compressor (14) for pressurization, and then enters the cold side of the low-temperature regenerator (12) to absorb heat; the other stream enters the auxiliary compressor (15) for pressurization, and the pressurized working fluid merges with the cold side outlet stream of the low-temperature regenerator (12), and enters the high-temperature regenerator (11) for cold absorption, and finally enters the heat exchanger (8) to absorb heat, forming a complete supercritical CO2 Brayton cycle.

2. The copper-chlorine cycle hydrogen / power cogeneration system with complementary coupling of solar energy and natural gas according to claim 1, characterized in that: The concentrating assembly (1) is used to concentrate sunlight onto the tubular receiver (2) to enhance the intensity of solar radiation; a photothermal absorber is fixed inside the tubular receiver (2) to absorb the focused sunlight and convert it into thermal energy to preheat the oxygen-enriched air.

3. The copper-chlorine cycle hydrogen / power cogeneration system with complementary coupling of solar energy and natural gas according to claim 1, characterized in that: The methane oxygen-enriched combustion high-temperature photovoltaic power generation device further comprises an emitter (4), a filter (5), a photovoltaic cell (6) and a photovoltaic cell waste heat utilization device (7); the first-stage high-temperature flue gas generated by the oxygen-enriched combustion of natural gas in the combustion chamber (3) generates radiation energy through the emitter (4), and the radiation energy selectively passes through the filter (5) and is absorbed by the photovoltaic cell (6) to generate electrical energy, and the generated electricity is stored in the storage battery (22); the photovoltaic cell waste heat utilization device (7) recovers the heat energy of the photovoltaic cell (6) to preheat water as a raw material for a thermochemical reaction, while avoiding the temperature rise of the photovoltaic cell due to the large amount of radiation energy.

4. The copper-chlorine cycle hydrogen / power cogeneration system with complementary coupling of solar energy and natural gas according to claim 1, characterized in that: The thermochemical reaction device comprises a pyrolysis reaction chamber (16), a hydrolysis reaction chamber (17), a drying reaction chamber (18) and an electrolysis reaction chamber (19); The pyrolysis reaction chamber (16) uses the heat contained in the third-stage high-temperature flue gas to promote the pyrolysis reaction. After heat exchange, the third-stage high-temperature flue gas is converted into the fourth-stage high-temperature flue gas with a temperature of 400-460°C and supplied to the hydrolysis reaction chamber (17). The chemical reaction equation of the pyrolysis reaction is Cu2OCl2(s)→2CuCl(l)+0.5O2(g); The hydrolysis reaction chamber (17) utilizes the heat contained in the fourth-stage high-temperature flue gas to promote the hydrolysis reaction. After heat exchange, the fourth-stage high-temperature flue gas is converted into the fifth-stage high-temperature flue gas with a temperature of 130-200°C and supplied to the drying reaction chamber (18). The chemical reaction equation of the hydrolysis reaction is 2CuCl2(s)+H2O(g)→2HCl(g)+Cu2OCl2(s). The product HCl gas is supplied to the electrolysis reaction chamber (19) as a raw material for the electrolysis reaction. The drying reaction chamber (18) utilizes the heat contained in the fifth-stage high-temperature flue gas to promote the drying reaction, evaporates the water in the CuCl2 solution to form solid CuCl2, and after heat exchange, the fifth-stage high-temperature flue gas is converted into low-temperature flue gas and discharged; The electrolysis reaction chamber (19) utilizes part of the electricity generated by the methane oxygen-enriched combustion high-temperature photovoltaic power generation device to promote the electrolysis reaction. The chemical reaction equation is 2CuCl(aq)+2HCl(g)→H2(g)+2CuCl2(aq); The thermochemical reaction device constitutes a complete four-step copper-chlorine cycle, and its net reaction is the decomposition of water into hydrogen and oxygen.

5. The copper-chlorine cycle hydrogen / power cogeneration system with complementary coupling of solar energy and natural gas according to claim 1, characterized in that: The system further includes a solid-liquid material transport system, which transports solid Cu2OCl2 and HCl gas generated by the reaction in the hydrolysis reaction chamber (17) into the pyrolysis reaction chamber (16) and the electrolysis reaction chamber (19), respectively, transports the liquid CuCl2 generated by the reaction in the pyrolysis reaction chamber (16) into the electrolysis reaction chamber (19), transports the CuCl2 solution generated by the reaction in the electrolysis reaction chamber (19) into the drying reaction chamber (18), and transports the CuCl2 solid generated by the reaction in the drying reaction chamber (18) into the hydrolysis reaction chamber (17).

6. The copper-chlorine cycle hydrogen / power cogeneration system with complementary coupling of solar energy and natural gas according to claim 1, characterized in that: The system further comprises a hydrogen storage tank (20) and an oxygen storage tank (21). The hydrogen storage tank (20) is connected to the hydrogen outlet of the electrolysis reaction chamber (19) to store hydrogen, and the oxygen storage tank (21) is connected to the oxygen outlet of the pyrolysis reaction chamber (16) to store oxygen. The oxygen in the oxygen storage tank (21) is mixed with air to form oxygen-enriched air to be supplied to the tubular receiver (2).

7. The copper-chlorine cycle hydrogen / power cogeneration system with complementary coupling of solar energy and natural gas as claimed in claim 1, characterized in that: By regulating the ratio of air and oxygen entering the tubular receiver (2), that is, regulating the oxygen content in the oxygen-enriched air, the instability of solar energy is balanced to ensure continuous operation of the system day and night.

8. A method for hydrogen / electricity cogeneration using a copper-chlorine cycle with complementary coupling of solar energy and natural gas based on the system according to any one of claims 1 to 7, characterized in that: Low-grade solar energy and natural gas are combined to enhance energy quality, and based on the principle of energy quality matching, complementary coupling of different qualities is achieved on the basis of energy cascade conversion. The method comprises the following steps: The oxygen-enriched air is preheated by solar energy in the tubular receiver (2) and then introduced into the combustion chamber (3) together with the natural gas for combustion, thereby generating a first-stage high-temperature flue gas having a temperature of 2000-2500°C; the radiation energy contained in the first-stage high-temperature flue gas is used by the methane oxygen-enriched combustion high-temperature photovoltaic power generation device to generate thermal photovoltaic power, and the radiation energy is converted into a second-stage high-temperature flue gas having a temperature of 850-1000°C and introduced into the heat exchanger (8); The supercritical CO2 Brayton cycle device utilizes the heat energy contained in the second-stage high-temperature flue gas in the heat exchanger (8) to drive the supercritical CO2 Brayton cycle to generate electricity, and the third-stage high-temperature flue gas with a discharge temperature of 530-680°C from the heat exchanger (8) is introduced into the pyrolysis reaction chamber (16); The pyrolysis reaction chamber (16) uses the heat energy contained in the third-stage high-temperature flue gas to drive the pyrolysis reaction, converting it into the fourth-stage high-temperature flue gas with a temperature of 400-460°C, which is then passed into the hydrolysis reaction chamber (17); the hydrolysis reaction chamber (17) uses the heat energy contained in the fourth-stage high-temperature flue gas to drive the hydrolysis reaction, converting it into the fifth-stage high-temperature flue gas with a temperature of 130-200°C, which is then passed into the drying reaction chamber (18); the drying reaction chamber (18) uses the heat energy contained in the fifth-stage high-temperature flue gas to drive the drying reaction, converting it into low-temperature flue gas for discharge; the electrolysis reaction chamber (19) of the thermochemical reaction device uses a portion of the electrical energy stored in the battery (22) to perform an electrolysis reaction to produce hydrogen, and the produced hydrogen is stored in the hydrogen storage tank (20).

9. The method for copper-chlorine cycle hydrogen / power cogeneration using complementary coupling of solar energy and natural gas as claimed in claim 8, characterized in that: The thermochemical reaction device utilizes the heat energy and electrical energy contained in the third, fourth and fifth stage high temperature flue gases in sequence to meet the different reaction temperature conditions and required energy types, which is conducive to the full progress of the reaction and enables the energy to be effectively utilized in a graded manner; The reaction temperature of the pyrolysis reaction chamber (16) is 500-530°C; the reaction temperature of the hydrolysis reaction chamber (17) is 370-400°C; the reaction temperature of the drying reaction chamber (18) is 100-130°C; and the reaction temperature of the electrolysis reaction chamber (19) is room temperature.

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