Solar energy and natural gas complementary coupling copper-chlorine recycle hydrogen / electricity co-production system and method

Abstract

The invention provides a solar energy and natural gas complementary coupling copper-chlorine recycle hydrogen / electricity co-production system and method. The system comprises a light condensation assembly used for enhancing the solar radiation intensity; the methane oxygen-enriched combustion high-temperature photovoltaic power generation device is used for realizing oxygen-enriched combustion by using natural gas and generating power by using radiation energy generated by first-stage high-temperature flue gas generated after combustion; the supercritical carbon dioxide Brayton cycle device is used for pushing power cycle power generation by utilizing heat energy contained in the second-stage high-temperature flue gas; and the thermal chemical reaction device is used for utilizing heat energy contained in the third-stage, fourth-stage and fifth-stage high-temperature flue gas to promote thermal chemical reaction in each step. Energy sources of the system are solar radiation and natural gas, and hydrogen and electricity are produced. Low-grade solar energy and natural gas are complementary, the energy grade is improved, based on the energy quality matching principle, electric / thermal energy of different qualities is supplied into thermochemical circulation in stages to prepare hydrogen, complementary coupling of energy of different qualities is achieved on the basis of energy cascade conversion, and the energy conversion efficiency is improved. And an efficient solar hydrogen-electricity co-production way is provided.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy preparation, and particularly relates to a copper-chlorine cycle hydrogen / electricity co-production system and method with complementary coupling of solar energy and natural gas. Background Art

[0002] Due to the advantages of solar energy such as cleanness, wide availability, and huge energy, it is regarded as one of the most promising green energies. As a clean secondary energy, hydrogen energy can be derived from water decomposition and is an important energy storage carrier. In the process of solar energy utilization, the low-grade solar energy cannot be effectively utilized, making it difficult to improve the utilization and conversion efficiency of solar energy. In addition, affected by the weather, the utilization of solar energy is unstable. Therefore, the complementary combination of low-grade solar energy and natural gas can effectively improve the energy grade, and theoretically, high-temperature flue gas exceeding 2000 °C can be obtained. However, there is still a lack of a single way to fully and efficiently utilize high-grade energy at present. Therefore, cascaded conversion and utilization of energy is a scientific and effective way. For high-temperature energy, thermophotovoltaic power generation is a new technology that directly converts high-grade thermal energy into electrical energy. The emitter is heated to a high temperature exceeding 1400 °C to generate radiant energy for photovoltaic power generation. In addition, the supercritical CO2 Brayton cycle has the advantages of high efficiency, flexibility, environmental protection, and economy. Since its applicable heat source temperature range is wide (200 - 850 °C), and by scientifically matching the system parameters, it has a relatively high operating efficiency compared with other thermal power conversion devices under the same temperature conditions. Therefore, it has broad application prospects in the fields of coal-fired power generation, solar thermal power generation, nuclear power, and waste heat power generation. Complementary advantages of different technologies can be used to achieve cascaded energy conversion and improve energy utilization efficiency.

[0003] For hydrogen production, thermochemical water splitting for hydrogen production is a clean and efficient hydrogen production method, which is a thermochemical indirect decomposition water cycle constructed through the redox reaction of oxygen carrier materials. Compared with common thermochemical cycles for hydrogen production (usually requiring a temperature higher than 1000 °C), the highest 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, the pyrolysis, hydrolysis, and drying reactions require thermal energy of different grades, and the electrolysis reaction requires electrical energy, which can be matched with the complementary cascaded conversion and utilization methods of solar energy and natural gas (power generation and heat supply), realizing the complementary coupling of different-quality energies and providing an efficient solar hydrogen and electricity co-production approach. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the present application aims to provide a copper-chlorine cycle hydrogen / electricity co-production system and method that combines solar energy and natural gas complementarily, combines low-grade solar energy and natural gas to improve the energy grade, and based on the principle of energy quality matching, effectively utilizes and matches and couples the copper-chlorine cycle through different energy conversion forms to efficiently output hydrogen and electricity, greatly improving the energy utilization efficiency.

[0005] On the one hand, the present application proposes a copper-chlorine cycle hydrogen / electricity co-production system that combines solar energy and natural gas complementarily, which includes a concentrating component, a high-temperature photovoltaic power generation device for methane oxy-fuel combustion, a supercritical CO2 Brayton cycle device, and a thermochemical reaction device;

[0006] The system has 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] Among them, the tubular receiver and the combustion chamber are components of the high-temperature photovoltaic power generation device for methane oxy-fuel combustion. The gas pipeline inputs oxygen-rich air into the tubular receiver. The tubular receiver absorbs the sunlight focused by the concentrating component and preheats the oxygen-rich air; the preheated oxygen-rich air and natural gas are input into the combustion chamber for combustion together. The combustion chamber generates a first-stage high-temperature flue gas to generate radiant energy through a transmitter, and the high-temperature photovoltaic power generation device for methane oxy-fuel combustion uses the radiant energy for photovoltaic power generation, and the combustion chamber discharges a second-stage high-temperature flue gas;

[0008] The heat exchanger is a component of the supercritical CO2 Brayton cycle device, and 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 for power generation, and the heat exchanger supplies the third-stage high-temperature flue gas after heat exchange to the pyrolysis reaction chamber;

[0009] The pyrolysis reaction chamber, the hydrolysis reaction chamber, and the drying reaction chamber gradually utilize the heat energy contained in the high-temperature flue gas for reactions, and they are all components of the thermochemical cycle device. The entire thermochemical cycle device uses the heat energy contained in the high-temperature flue gas and the electric energy of the high-temperature photovoltaic power generation device for methane oxy-fuel combustion to realize the copper-chlorine cycle, generating hydrogen and oxygen.

[0010] On the other hand, the present application also proposes a method for copper-chlorine cycle hydrogen / electricity co-production that combines solar energy and natural gas complementarily, including the following steps: The oxygen-rich air is preheated by solar energy in the tubular receiver and then input into the combustion chamber together with natural gas for combustion, generating a first-stage high-temperature flue gas with a temperature of 2000 - 2500 °C; the high-temperature photovoltaic power generation device for methane oxy-fuel combustion uses the radiant energy contained in the first-stage high-temperature flue gas for thermophotovoltaic power generation, converting it into a second-stage high-temperature flue gas with a temperature of 850 - 1000 °C and inputting it into the heat exchanger;

[0011] The supercritical CO2 Brayton cycle device utilizes the thermal energy contained in the second-stage high-temperature flue gas in the heat exchanger to drive the supercritical CO2 Brayton cycle for power generation. The third-stage high-temperature flue gas with a discharged temperature of 530 - 680 °C from the heat exchanger is introduced into the pyrolysis reaction chamber;

[0012] The pyrolysis reaction chamber utilizes the thermal 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 and introducing it into the hydrolysis reaction chamber; the hydrolysis reaction chamber utilizes the thermal 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 and introducing it into the drying reaction chamber; the drying reaction chamber utilizes the thermal energy contained in the fifth-stage high-temperature flue gas to drive the drying reaction, converting it into low-temperature flue gas and discharging it; the electrolysis reaction chamber of the thermochemical reaction device uses a part of the electric energy stored in the storage battery to carry out the electrolysis reaction to produce hydrogen, and the produced hydrogen is stored in the hydrogen storage tank.

[0013] The system and method proposed in this application have the following advantages or beneficial effects: Complementary use of low-grade solar energy and natural gas, obtaining the first-stage high-temperature flue gas with a temperature of 2000 - 2500 °C through oxy-fuel combustion, effectively improving the energy grade; Based on the principle of energy quality matching, using the first-stage high-temperature flue gas with a temperature of 2000 - 2500 °C for high-temperature thermophotovoltaic power generation, and using the second-stage high-temperature flue gas with a temperature of 850 - 1000 °C to drive the supercritical CO2 Brayton cycle for power generation; Using different-quality electric / thermal energy to be fed into the thermochemical cycle in stages to produce hydrogen, realizing the complementary coupling of different qualities on the basis of energy cascade conversion, using the third, fourth, and fifth-stage high-temperature flue gases with gradually decreasing temperatures to drive the pyrolysis, hydrolysis, and drying reactions in the thermochemical cycle respectively, and using the electricity generated by thermophotovoltaic to drive the electrolysis reaction in the thermochemical cycle, that is, constituting a complete four-step copper-chlorine cycle for hydrogen production; The oxygen generated by the pyrolysis reaction can be used as a raw material for oxy-fuel combustion. In this application, the oxygen content in the oxy-fuel air is regulated to balance the instability of solar energy to ensure the self-sustaining operation of the system day and night; The heat generated by the photovoltaic cell power generation is used to preheat the water required for the thermochemical cycle, which can not only avoid the temperature rise of the photovoltaic cell due to a large amount of radiant energy, but also be beneficial to improving the energy utilization efficiency of the system; This application provides an efficient solar hydrogen and electricity co-production approach, the energy source of the system is solar radiation and natural gas, and the outputs are hydrogen and electricity; The secondary energy utilization efficiency of this application can exceed 60%, and the equivalent electricity efficiency can exceed 52%. Description of the Drawings

[0014] Figure 1 It is a schematic diagram of the structure of a solar and natural gas complementary coupling copper-chlorine cycle hydrogen / electricity co-production system according to an embodiment of the present application;

[0015] Among them, 1 - concentrating component, 2 - tubular receiver, 3 - combustion chamber, 4 - emitter, 5 - filter, 6 - photovoltaic cell, 7 - photovoltaic cell waste heat utilization device, 8 - heat exchanger, 9 - turbine, 10 - generator, 11 - high-temperature recuperator, 12 - low-temperature recuperator, 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 - storage battery. Detailed implementation manners

[0016] For a better understanding of the technical solution of the present application, the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0017] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention and are intended to explain the inventive concept. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present invention.

[0018] Unless otherwise clearly specified and limited, the terms "high temperature", "low temperature", "high pressure", "low pressure", etc. used in the description 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 clearly specified and limited, the terms "connected" and "coupled" used in the description should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection; it can be directly connected, indirectly connected through an intermediate medium; it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments can be understood according to specific situations.

[0020] The embodiments of the present application provide a copper-chlorine cycle hydrogen / electricity co-production system with complementary coupling of solar energy and natural gas, and a method for hydrogen and electricity co-production using this system.

[0021] See Figure 1, in a specific embodiment of the present application, a copper-chlorine cycle hydrogen / electricity co-production system with complementary coupling of solar energy and natural gas is provided, including a concentrating component 1, a high-temperature photovoltaic power generation device for methane oxy-fuel combustion, a supercritical CO2 Brayton cycle device, and a thermochemical reaction device; wherein, the concentrating component 1 is mainly used to concentrate sunlight onto the tubular receiver 2 of the high-temperature photovoltaic power generation device for methane oxy-fuel combustion, enhancing the solar radiation intensity to more effectively utilize solar energy. The high-temperature photovoltaic power generation device for methane oxy-fuel combustion, on the one hand, uses solar energy to preheat the oxygen-rich air, and on the other hand, uses the preheated oxygen-rich air to burn natural gas to generate high-temperature flue gas to drive the subsequent supercritical CO2 Brayton cycle device and thermochemical reaction device, and it also uses the radiant energy of the high-temperature flue gas for photovoltaic power generation of the photovoltaic power generation device; the supercritical CO2 Brayton cycle device uses the high-temperature flue gas generated by the high-temperature photovoltaic power generation device for methane oxy-fuel combustion to drive supercritical CO2 Brayton cycle power generation; the thermochemical reaction device uses the thermal energy contained in the high-temperature flue gas after heat exchange by the supercritical CO2 Brayton cycle device and the electric energy of the high-temperature photovoltaic power generation device for methane oxy-fuel combustion to achieve the copper-chlorine cycle, generating hydrogen and oxygen, and the oxygen can be further supplied to the high-temperature photovoltaic power generation device for methane oxy-fuel combustion to regulate the oxygen content in the oxygen-rich air. The energy source of this system is solar radiation and natural gas, and the outputs are hydrogen and electricity. Each system works together to complement low-grade solar energy and natural gas, effectively improving the energy grade through oxy-fuel combustion; based on the principle of energy quality matching, high-temperature flue gas at different temperatures is used for high-temperature thermal photovoltaic power generation, driving supercritical CO2 Brayton cycle power generation, and thermochemical cycle to produce hydrogen respectively, realizing complementary coupling of different qualities on the basis of energy cascade conversion. This system makes full use of the energy grade and has a very high secondary energy utilization efficiency.

[0022] It should be noted that there is an air / flue gas pipeline (gas pipeline) for heat transfer in the system of the present invention. This air / flue gas pipeline is successively connected to the tubular receiver 2 and the combustion chamber 3 of the high-temperature photovoltaic power generation device for methane oxy-fuel combustion, 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, so as to realize the cascade conversion and utilization of high-temperature flue gas energy at different temperatures.

[0023] In an embodiment of the present invention, the concentrating component 1 concentrates sunlight onto the tubular receiver 2, enhancing the solar radiation intensity. Preferably, the concentrating component 1 adopts a point-focusing Fresnel concentrating component, which has mature products and low prices.

[0024] As Figure 1As shown, in one embodiment of the present invention, the high-temperature photovoltaic power generation device for oxy-fuel combustion of methane includes a tubular receiver 2, a combustion chamber 3, a emitter 4, a filter 5, a photovoltaic cell 6, and a photovoltaic cell waste heat utilization device 7. A photo-thermal absorber is fixed inside the tubular receiver 2, which absorbs the sunlight focused by the concentrating assembly 1 and converts it into heat energy to preheat the oxygen-enriched air introduced into the tubular receiver 2, generating oxygen-enriched air at a temperature of 600 - 700 °C. Natural gas and the preheated oxygen-enriched air are jointly input into the combustion chamber 3 for oxy-fuel combustion, generating a first-stage high-temperature flue gas at a temperature of 2000 - 2500 °C. The first-stage high-temperature flue gas generates radiant energy through the emitter 4, and the radiant energy selectively passes through the filter 5 and is absorbed by the photovoltaic cell 6 to generate electric energy. The radiant energy that does not match the photovoltaic cell returns to the combustion chamber 3. Subsequently, the first-stage high-temperature flue gas is converted into a second-stage high-temperature flue gas at 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, obtaining hot water at a temperature of 40 - 60 °C as the raw material for the pyrolysis reaction in the thermochemical cycle, improving the energy utilization efficiency and simultaneously avoiding the temperature rise of the photovoltaic cell due to a large amount of radiant energy. Preferably, the tubular receiver 2 is provided with an inlet for introducing air, an inlet for introducing oxygen, and an outlet for discharging the preheated oxygen-enriched air. The inlet for introducing oxygen is connected to the outlet of the oxygen storage tank 21; the combustion chamber 3 is provided with an inlet for introducing oxygen-enriched air and an outlet for discharging the second-stage high-temperature flue gas. The inlet for introducing 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 introducing cold water and an outlet for discharging hot water. Preferably, the photovoltaic cell 6 uses a gallium arsenide (GaAs) photovoltaic cell with a cut-off wavelength of 900 nm. This type of photovoltaic cell has a high photoelectric conversion efficiency, can withstand high temperatures and high-concentration ratio light, and better meets the system requirements.

[0025] As Figure 1As shown, in an embodiment of the present invention, the supercritical CO2 Brayton cycle device includes a heat exchanger 8, a turbine 9, a generator 10, a high-temperature recuperator 11, a low-temperature recuperator 12, a precooler 13, a main compressor 14, and an auxiliary compressor 15 that are connected. The heat exchanger 8 utilizes the heat contained in the second-stage high-temperature flue gas to drive the supercritical CO2 Brayton cycle for power generation. After heat exchange, the second-stage high-temperature flue gas is converted into the third-stage high-temperature flue gas at 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, high-pressure CO2 first absorbs 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, 25 MPa); the high-temperature and high-pressure working fluid enters the turbine 9 to do work and generate electricity, becoming a low-pressure working fluid, and the electric energy is output through the generator 10; the low-pressure working fluid enters the hot side of the high-temperature recuperator 11 to release heat, and then enters the low-temperature recuperator 12 to continue releasing heat; the working fluid is divided into two streams at the hot-side outlet of the low-temperature recuperator 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, 7.38 MPa) enters the main compressor 14 for pressurization and then enters the cold side of the low-temperature recuperator 12 to absorb heat; the other stream enters the auxiliary compressor 15 for pressurization, and the pressurized working fluid converges with the flow stream at the cold-side outlet of the low-temperature recuperator 12, and together enters the cold side of the high-temperature recuperator 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 introducing the second-stage high-temperature flue gas, an outlet for discharging the third-stage high-temperature flue gas, an inlet for introducing the low-temperature supercritical working fluid, and an outlet for discharging the high-temperature supercritical working fluid. The inlet for introducing 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 introducing 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 at 850°C, the lowest and highest pressures in the supercritical CO2 Brayton cycle are set at 7.38 MPa and 25 MPa respectively, and the cycle efficiency can exceed 60%.

[0026] As Figure 1 shown, in an 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 drive 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 the fourth-stage high-temperature flue gas at 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 drive the hydrolysis reaction, maintaining the temperature in the hydrolysis reaction chamber at 370 - 400 °C. After heat exchange, the fourth-stage high-temperature flue gas is converted into the fifth-stage high-temperature flue gas at 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 as a raw material for the electrolysis reaction to the electrolysis reaction chamber 19.

[0029] The drying reaction chamber 18 utilizes the heat contained in the fifth-stage high-temperature flue gas to drive the drying reaction, evaporating the water in the CuCl2 solution to form solid CuCl2, maintaining the temperature in the drying reaction chamber at 100 - 130 °C, and 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 drive the electrolysis reaction, and the chemical reaction equation is 2CuCl(aq) + 2HCl(g) → H2(g) + 2CuCl2(aq).

[0031] The above thermochemical reactions constitute a complete cycle, namely the four-step copper-chlorine cycle, and its 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 its different reaction temperature conditions and the required energy types, which is conducive to the full progress of the reaction and enables the graded and effective utilization of energy. 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 transfer system. Through the solid-liquid material transfer system, the solid Cu2OCl2 and HCl gas generated in the hydrolysis reaction chamber 17 are respectively transported into the pyrolysis reaction chamber 16 and the electrolysis reaction chamber 19, the liquid CuCl generated in the pyrolysis reaction chamber 16 is transported into the electrolysis reaction chamber 19, the CuCl2 solution generated in the electrolysis reaction chamber 19 is transported into the drying reaction chamber 18, and the CuCl2 solid generated in the drying reaction chamber 18 is transported into the hydrolysis reaction chamber 17. The solid-liquid material transfer system recovers and transports the reusable solid-liquid products generated in each device, realizes the recycling of substances in the hydrogen production system, reduces the production cost, and also avoids polluting the environment.

[0033] As 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 storage battery 22. Among them, 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 storage battery 22 is used to store the electric energy 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 complementary coupling of solar energy and natural gas for copper-chlorine cycle hydrogen / electricity co-production, including the following steps: The oxygen-enriched air is preheated by solar energy in the tubular receiver 2 and heated to 600-700 °C, and then is introduced into the combustion chamber 3 together with natural gas for combustion to generate a first-stage high-temperature flue gas with a temperature of 2000-2500 °C; The methane oxy-fuel combustion high-temperature photovoltaic power generation device uses the radiant energy contained in the first-stage high-temperature flue gas with a temperature of 2000-2500 °C for thermophotovoltaic power generation, converts it into a second-stage high-temperature flue gas with a temperature of 850-1000 °C and introduces it into the supercritical CO2 Brayton cycle device, and the generated electricity is stored in the storage battery 22; The supercritical CO2 Brayton cycle device uses the thermal energy contained in the second-stage high-temperature flue gas with a temperature of 850-1000 °C to drive the supercritical CO2 Brayton cycle for power generation, and the generated electricity is used to supply the power grid, and it is converted into a third-stage high-temperature flue gas with a temperature of 530-680 °C and 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 in-cycle turbine 9 is about 850 °C; The pyrolysis reaction chamber 16 uses the thermal energy contained in the third-stage high-temperature flue gas with a temperature of 530-680 °C to drive the pyrolysis reaction, converts it into a fourth-stage high-temperature flue gas with a temperature of 400-460 °C and introduces it into the hydrolysis reaction chamber 17, so that the temperature in the pyrolysis reaction chamber 16 is maintained at 500-530 °C; The hydrolysis reaction chamber 17 uses the thermal energy contained in the fourth-stage high-temperature flue gas with a temperature of 400-460 °C to drive the hydrolysis reaction, converts it into a fifth-stage high-temperature flue gas with a temperature of 130-200 °C and introduces it into the drying reaction chamber 18, so that the temperature in the hydrolysis reaction chamber 17 is maintained at 370-400 °C; The drying reaction chamber 18 uses the thermal energy contained in the fifth-stage high-temperature flue gas with a temperature of 130-200 °C 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 100-130 °C.

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

[0036] In a specific embodiment, the method further includes the following steps: using a part of the electric energy stored in the storage battery 22 through the electrolysis reaction chamber 19 to carry out electrolysis reaction to produce hydrogen, and storing the produced hydrogen in the hydrogen storage tank 20; storing the oxygen generated in the pyrolysis reaction chamber 16 in the oxygen storage tank 21, and partially introducing it into the tubular receiver 2 to be mixed 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, to balance the instability of solar energy and ensure the 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 electric energy, and excessive preheated hot water is introduced to ensure the full progress of the reaction. To ensure safety, the temperature of the oxygen-enriched air preheated by the concentrated solar energy does not exceed 700 °C, and the natural gas feed power is 15 kW. The power generation power of the methane oxygen-enriched combustion high-temperature photovoltaic power generation device is 8.19 kW, the power generation power of the supercritical CO2 Brayton cycle device is 0.57 kW, the power consumption of the thermochemical cycle is 0.72 kW, and the hydrogen production power is 3.16 kW. The secondary energy utilization efficiency of the system is 61.26%, and the equivalent electric efficiency is 52.95%. It can be seen that the system and method of the present invention complement low-grade solar energy with natural gas, improve the energy grade, and based on the principle of energy quality matching, use different-quality electric / thermal energy to be fed into the thermochemical cycle in stages to produce hydrogen, realizing the complementary coupling of different-quality energies on the basis of energy cascade conversion, and providing an efficient solar hydrogen and electricity co-production approach.

[0038] The foregoing are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope 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 comprises a focusing 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 the sunlight focused by the focusing component (1) and preheats the oxygen-enriched air. The preheated oxygen-enriched air and natural gas are input into the combustion chamber (3) for combustion. The combustion chamber (3) generates first-stage high-temperature flue gas which generates radiation energy through the transmitter (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 promote 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) use 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 uses the heat energy contained in the high-temperature flue gas and the electric energy of the methane oxygen-enriched combustion high-temperature photovoltaic power generation device to realize the copper-chlorine cycle and generate hydrogen and oxygen.

2. The copper-chlorine cycle hydrogen / electricity cogeneration system of complementary coupling of solar energy and natural gas as claimed in claim 1, characterized in that: The focusing assembly (1) is used to focus 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 / electricity cogeneration system of complementary coupling of solar energy and natural gas as claimed in claim 1, characterized in that: The methane oxygen-enriched combustion high-temperature photovoltaic power generation device also includes a transmitter (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 transmitter (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 a large amount of radiation energy.

4. The copper-chlorine cycle hydrogen / electricity cogeneration system of complementary coupling of solar energy and natural gas as claimed in claim 1, characterized in that: 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, the 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; After entering the turbine (9), the high-temperature and high-pressure working fluid performs work and generates electricity, becoming 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) to release heat, and then enters the low-temperature regenerator (12) to continue to release 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 to release 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 side absorption, and finally enters the heat exchanger (8) for heat absorption, forming a complete supercritical CO2 Brayton cycle.

5. The copper-chlorine cycle hydrogen / electricity cogeneration system with complementary coupling of solar energy and natural gas as claimed in 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) utilizes 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 a fourth-stage high-temperature flue gas with a temperature of 400 to 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 to 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 for discharge; The electrolytic reaction chamber (19) utilizes part of the electricity generated by the methane oxygen-enriched combustion high-temperature photovoltaic power generation device to promote the electrolytic reaction, and 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.

6. The copper-chlorine cycle hydrogen / electricity cogeneration system with complementary coupling of solar energy and natural gas as claimed in claim 1, characterized in that: The system further comprises a solid-liquid material transport system, wherein the solid-liquid material transport system 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 liquid CuCl2 generated by the reaction in the pyrolysis reaction chamber (16) into the electrolysis reaction chamber (19), transports CuCl2 solution generated by the reaction in the electrolysis reaction chamber (19) into the drying reaction chamber (18), and transports CuCl2 solid generated by the reaction in the drying reaction chamber (18) into the hydrolysis reaction chamber (17).

7. The copper-chlorine cycle hydrogen / electricity cogeneration system of complementary coupling of solar energy and natural gas as claimed in 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).

8. The copper-chlorine cycle hydrogen / electricity cogeneration system with complementary coupling of solar energy and natural gas as claimed in claim 1, characterized in that: By adjusting the ratio of air and oxygen entering the tubular receiver (2), that is, adjusting 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.

9. A method for hydrogen / electricity cogeneration by copper-chlorine cycle using complementary coupling of solar energy and natural gas based on the system of any one of claims 1 to 8, characterized in that: The low-grade solar energy and natural gas are complemented to improve the energy quality, and based on the energy quality matching principle, the 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 to 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 to 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 to 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 introduced 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 introduced 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 electric energy stored in the storage battery (22) to perform an electrolysis reaction to produce hydrogen, and the produced hydrogen is stored in the hydrogen storage tank (20).

10. The method for copper-chlorine cycle hydrogen / electricity cogeneration by complementary coupling of solar energy and natural gas as claimed in claim 9, characterized in that: The thermochemical reaction device utilizes the heat energy and electric energy contained in the third, fourth and fifth stage high temperature flue gas in sequence to meet the different reaction temperature conditions and required energy types, which is conducive to the full reaction and enables the energy to be effectively utilized in stages; 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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