Three-stage condensation frequency division driving copper-chlorine circulation hydrogen production system

Abstract

The invention discloses a three-stage condensation and frequency division copper-chlorine circulation hydrogen production system. The system comprises a solar full-spectrum three-stage condensation and frequency division utilization subsystem and a copper-chlorine circulation hydrogen production subsystem. The solar full-spectrum three-level light-focusing frequency-division utilization subsystem is used for realizing light focusing of three different solar multi-spectrum light focusing times; a photovoltaic available spectrum is converted into electric energy, heat energy of different temperatures is generated from the residual spectrum through a radiation absorber, and full-spectrum utilization of solar energy is achieved. And the copper-chlorine circular hydrogen production subsystem performs four-step copper-chlorine circular reaction to produce hydrogen by using electric energy generated by the photovoltaic power generation assembly and heat energy at different temperatures generated by different radiation absorbers. According to the copper-chlorine circulating purification reaction, water is decomposed into hydrogen and oxygen, according to the energy requirement and energy quality matching principle of the whole process, the energy source of the system completely comes from electric energy converted from solar radiation energy and heat energy at different temperatures, and the method is a reasonable and efficient solar clean hydrogen production path.

Description

Technical Field

[0001] This invention belongs to the field of new energy preparation technology for energy quality cascade utilization, specifically involving a three-stage concentrated frequency division driven copper-chlorine cycle hydrogen production system. Background Technology

[0002] Solar energy, with its vast total amount, is the most promising clean and renewable energy source, but it also suffers from inherent drawbacks such as intermittency and volatility. Currently, the development and utilization of solar energy mainly relies on two pathways for photoelectric conversion: photovoltaic (PV) and concentrated solar thermal (CSP). PV technology generates electricity based on the photovoltaic principle. PV power generation directly converts solar radiation into electrical energy, making it a renewable energy generation technology with the most ideal characteristics for sustainable development. However, different wavelengths of solar radiation contain different amounts of energy, and PV cells are limited by their own energy band gap, preventing them from utilizing the full solar spectrum, thus limiting PV efficiency. Solar full-spectrum frequency division technology can achieve efficient utilization of solar radiation energy across the entire spectrum based on energy quality through electro-thermal coupling.

[0003] Hydrogen energy boasts high energy density and strong environmental friendliness, making it a reliable energy source to address the intermittency of solar energy. Among existing methods for producing hydrogen using solar energy, solar thermochemical cycle hydrogen production is an important green method, with the net reaction being the decomposition of water to produce hydrogen and oxygen. Solar thermochemical cycle hydrogen production primarily utilizes concentrated solar power technology to convert solar energy into thermal energy to drive indirect water decomposition for hydrogen production. The heat required for the copper-chlorine cycle (25-530℃) can all be derived from concentrated solar energy.

[0004] According to the second law of thermodynamics, thermal energy at different temperatures has different energy qualities. Copper-chlorine cycle hydrogen production systems typically include four reaction stages (drying reaction, hydrolysis reaction, pyrolysis reaction, and electrolysis reaction). Each reaction stage occurs at different temperatures and requires thermal and electrical energy of different qualities. Currently, single solar energy utilization devices are insufficient to meet the different thermal and electrical energy requirements of copper-chlorine cycle hydrogen production systems. Summary of the Invention

[0005] Based on the advantages and shortcomings of the aforementioned technologies, this application aims to provide a multi-stage concentrating and frequency-dividing driven copper-chlorine cycle hydrogen production system. This invention, based on the principle of energy quality matching, constructs a solar multi-stage concentrating and frequency-dividing energy conversion hydrogen production system. Utilizing a three-stage solar spectrum concentrator, frequency-dividing module, photovoltaic module, radiation absorber, thermal storage module, heat exchange module, and a copper-chlorine cycle thermochemical reaction device, an energy quality-matched coupled hydrogen production system is constructed, which can improve energy conversion efficiency.

[0006] To address the technical challenges, this invention proposes a multi-stage concentrated photovoltaic (PV) frequency division driven copper-chlorine cycle hydrogen production system, comprising a three-stage PV frequency division utilization subsystem and a copper-chlorine cycle hydrogen production subsystem. The three-stage PV frequency division utilization subsystem includes a three-stage solar PV concentrator, two frequency division components, three radiation absorbers, a photovoltaic power generation module, a battery, three thermal storage components, and three heat exchange components. The three-stage solar PV concentrator concentrates sunlight at three different concentration ratios. The low- and medium-concentration beams are each divided by two frequency division components. The usable photovoltaic wavelengths after frequency division enter the photovoltaic power generation module for photovoltaic power generation, while the remaining wavelengths enter the low-temperature and medium-temperature radiation absorbers to produce heat energy at different temperatures. The high-concentration beam directly enters the high-temperature radiation absorber to produce heat energy. The battery is used to store the electrical energy generated by the photovoltaic power generation module; The heat storage component is used to store a portion of the heat generated by the radiation absorber; the three heat exchanger components respectively utilize the thermal energy of the three radiation absorbers to heat the reactants in the copper-chlorine cycle hydrogen production reactor. The copper-chlorine cycle hydrogen production subsystem includes a copper-chlorine cycle hydrogen production reactor; the copper-chlorine cycle hydrogen production reactor includes a drying reactor, a hydrolysis reactor, a pyrolysis reactor, and an electrolysis reactor; the copper-chlorine cycle hydrogen production reactor utilizes the electrical energy generated by photovoltaic power generation components and the thermal energy generated by different radiation absorbers to carry out a four-step copper-chlorine cycle hydrogen production reaction, the net reaction of which is the decomposition of water into hydrogen and oxygen.

[0007] According to a preferred embodiment of the present invention, the three-stage solar spectrum concentrator includes a first-stage low-power concentrator using a trough concentrator, a second-stage medium-power concentrator using a dish concentrator; The first-stage low-concentration module provides a concentration ratio of 75 to 85 times. The resulting concentrated beam enters the low-concentration frequency division module for spectral frequency division. The usable photovoltaic band light energy is used to generate electricity for the photovoltaic power generation module, and the remaining band light energy enters the low-temperature radiation absorber to provide heat for the drying reaction in the drying reactor that requires low-temperature thermal energy. The second-stage medium-multiplexing photovoltaic module provides a concentration ratio of 145 to 155 times. The resulting concentrated beam enters the medium-multiplexing frequency divider for spectral frequency division. The usable photovoltaic band light energy is used for photovoltaic cell power generation, and the remaining band light energy enters the medium-temperature radiation absorber to heat the hydrolysis reaction in the hydrolysis reactor. The third-stage high-concentration module provides a concentration factor of 245 to 255 times, and the resulting concentrated beam enters the high-temperature radiation absorber to heat the pyrolysis reaction in the pyrolysis reactor. The electricity generated by the photovoltaic cell module is stored in a battery and used to power the electrolysis reaction in the electrolysis reactor; the photovoltaic power generation module has a photovoltaic cell waste heat utilization device, which recovers the heat energy of the photovoltaic power generation module to preheat hot water as a raw material for the copper-chlorine cycle reaction.

[0008] Compared with existing technologies, the solar spectrum multi-stage concentrating module of the present invention is designed with different concentration ratios according to the different energy and temperature requirements of each step of the subsequent coupled copper-chlorine cycle. It includes a first-stage low-concentration module, a second-stage medium-concentration module, and a third-stage high-concentration module. The concentrated beam obtained by the first-stage low-concentration module enters a low-concentration frequency divider for spectral frequency division. Part of the light energy in one wavelength band is used for photovoltaic power generation, and the remaining light energy enters a low-temperature radiation absorber to heat the drying reaction. The concentrated beam obtained by the second-stage medium-concentration module enters a medium-concentration frequency divider for spectral frequency division. Part of the light energy in one wavelength band is used for photovoltaic power generation, and the remaining light energy enters a medium-temperature radiation absorber to heat the hydrolysis reaction. The concentrated beam obtained by the third-stage high-concentration module enters a high-temperature radiation absorber to heat the pyrolysis reaction. The electricity generated by the photovoltaic module is used to power the electrolysis reaction. The thermal storage component stores some of the heat generated by the radiation absorber when there is sufficient solar energy input, and provides heat when there is insufficient solar energy input, in order to balance the instability of solar energy and ensure the stable operation of the system day and night; The copper-chlorine cycle hydrogen production reactor uses thermal energy obtained from different concentration ratios and frequency divisions, as well as photovoltaic power generation to drive the four steps in the cycle, so that the energy input to the reaction cycle matches the energy quality required for the reaction, producing hydrogen and oxygen.

[0009] This invention achieves decoupling of solar radiation energy quality through multi-stage concentrating and frequency division, correspondingly converting it into electrical / thermal energy coupling to drive copper-chlorine cycle hydrogen production with different energy qualities. This realizes the cascaded and orderly conversion of solar energy, which fundamentally conforms to the thermodynamic principle of energy cascade utilization.

[0010] Based on the different energy quality of the thermal energy required by the thermochemical cycle, this invention obtains thermal energy at different temperatures after frequency division by using different concentration ratios, which is used to drive the drying, hydrolysis and pyrolysis steps of the copper-chlorine cycle; at the same time, the photovoltaic cells can use the radiant energy of the spectrum to generate photovoltaic power, producing high-quality electrical energy, which is then used to drive the electrolysis step of the copper-chlorine cycle.

[0011] This invention balances the instability of solar energy by incorporating a thermal storage device, ensuring the system's self-sustaining operation day and night. Electro-thermal coupling-driven thermochemical cycle hydrogen production achieves high-energy-efficiency solar energy conversion and storage, without consuming any fossil fuels or producing any greenhouse gases.

[0012] All the energy used in the reaction of this invention system comes from solar energy, and the development of hydrogen energy using solar energy helps to transform the energy structure.

[0013] The power supply of the coupled hydrogen production system provided by this invention should be completed by multiple solar full-spectrum frequency division systems equipped with different frequency division components, photovoltaic cells and concentrating components, so as to achieve efficient energy cascade conversion under low concentration ratio conditions, reduce the complexity and cost of the concentrating system, improve the application potential, and the total solar hydrogen production efficiency can exceed 50%. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a three-stage concentrated light frequency division driven copper-chlorine cycle hydrogen production system proposed in this invention.

[0015] Among them, 1a~first-stage low-concentration photovoltaic module, 1b~second-stage medium-concentration photovoltaic module, 1c~third-stage high-concentration photovoltaic module, 2a~low-concentration frequency divider module, 2b~medium-concentration frequency divider module, 3~3a~low-temperature radiation absorber, 3b~medium-temperature radiation absorber, 3c~high-temperature radiation absorber, 4a~photovoltaic cell, 4b~photovoltaic cell waste heat utilization device, 5~battery, 6a~first-stage thermal storage module, 6b~second-stage thermal storage module, 6c~third-stage thermal storage module, 7a~low-temperature thermal oil heat exchanger, 7b~medium-temperature thermal oil heat exchanger, 7c~high-temperature molten salt heat exchanger, 8a~drying reactor, 8b~hydrolysis reactor, 8c~pyrolysis reactor, 8d~electrolysis reactor, 9~oxygen storage tank, 10~hydrogen storage tank. Detailed Implementation

[0016] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0017] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of 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. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] Unless otherwise expressly specified and limited, the terms “high temperature,” “medium temperature,” “low temperature,” “high magnification,” “medium magnification,” “low magnification,” 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 expressly specified and limited, the terms “primary”, “secondary”, etc. used in the description are for descriptive purposes only, in order to distinguish similar components or devices with different purposes and functions, and shall not be construed as indicating or implying relative importance or implicitly specifying the technical features indicated.

[0020] This application provides a multi-stage concentrated light frequency division driven copper-chlorine cycle hydrogen production system, and a coupling method for using this system to produce hydrogen.

[0021] See Figure 1 In one specific embodiment of this application, a three-stage concentrated light frequency division driven copper-chlorine cycle hydrogen production system is provided, including a solar full-spectrum three-stage concentrated light frequency division utilization subsystem and a copper-chlorine cycle hydrogen production subsystem; like Figure 1 As shown, in one embodiment of the present invention, the solar full-spectrum three-stage concentrating and frequency-dividing utilization subsystem includes a solar spectrum three-stage concentrating module, two frequency-dividing modules, three radiation absorbers, a photovoltaic power generation module, a battery, three thermal storage modules, and three heat exchange modules; the copper-chlorine cycle hydrogen production subsystem includes a copper-chlorine cycle hydrogen production reactor; the copper-chlorine cycle hydrogen production reactor includes a drying reactor, a hydrolysis reactor, a pyrolysis reactor, and an electrolysis reactor; the copper-chlorine cycle hydrogen production reactor utilizes the electrical energy generated by the photovoltaic power generation module and the thermal energy generated by different radiation absorbers to carry out a four-step copper-chlorine cycle hydrogen production reaction, the net reaction of which is the decomposition of water into hydrogen and oxygen.

[0022] The three-stage solar concentrator concentrates sunlight at three different concentration ratios. The low- and medium-concentration beams are divided by two frequency-dividing components. The usable photovoltaic light energy after frequency division enters the photovoltaic power generation module for photovoltaic power generation, while the remaining light energy enters the low-temperature radiation absorber and the medium-temperature radiation absorber respectively to produce heat energy at different temperatures. The high-concentration beam directly enters the high-temperature radiation absorber to produce heat energy. In this embodiment, the three-stage solar spectral concentrator 1 is designed with different concentration ratios based on the varying energy and temperature requirements of each step in the subsequent coupled copper-chlorine cycle. These include a first-stage low-concentration concentrator 1a, a second-stage medium-concentration concentrator 1b, and a third-stage high-concentration concentrator 1c. The first-stage low-concentration concentrator 1a uses a trough-type concentrator to provide a concentration ratio of 75-85 times. The resulting concentrated beam enters a low-concentration frequency divider 2a for spectral frequency division. Light energy in the 420-710nm band is used for power generation in photovoltaic cells 4a, while the remaining light energy enters a low-temperature radiation absorber 3a to provide heat for the low-temperature drying reaction in the drying reactor 6a. The second-stage medium-concentration concentrator 1b uses a dish or tower-type concentrator to provide a concentration ratio of 145-155 times, depending on the scale. The resulting concentrated beam enters a low-concentration frequency divider 2a for spectral frequency division. The medium-concentration photovoltaic (CPPV) module 2b performs spectral frequency division. The 480-650nm wavelength band light energy is used for photovoltaic cell 4a to generate electricity, and the remaining wavelength band light energy enters the medium-temperature radiation absorber 3b to provide heat for the hydrolysis reaction in the hydrolysis reactor 6b, which requires medium-temperature thermal energy. The third-stage high-concentration photovoltaic module 1c can use dish or tower concentrators to provide a concentration ratio of 245-255 times, depending on the scale. All the concentrated light beams obtained enter the high-temperature radiation absorber 3c to provide heat for the pyrolysis reaction in the pyrolysis reactor 6c, which requires high-temperature thermal energy. The design of using long wavelength bands for photovoltaic power generation with low-concentration frequency division, short wavelength bands for photovoltaic power generation with medium-concentration frequency division, and no frequency division for high-concentration photovoltaic can reduce the concentration ratio required for system operation, enabling the system to operate efficiently under lower concentration ratio conditions. This is beneficial to improving technical feasibility and economy, and improving energy utilization efficiency.

[0023] The two frequency division components of this invention are a low-concentration frequency division component 2a and a medium-concentration frequency division component 2b. Both are optical interference multilayer frequency division films formed by alternating deposition of TiO2 and SiO2 materials on a transparent substrate. In a specific embodiment of this invention, the low-concentration frequency division component 2a can transmit light in the 420-710nm wavelength band. Its structure consists of five layers: the first layer is SiO2 with a thickness of 40nm, the second layer is TiO2 with a thickness of 530nm, the third layer is SiO2 with a thickness of 15nm, the fourth layer is TiO2 with a thickness of 10nm, and the fifth layer is SiO2 with a thickness of 80nm. The medium-concentration frequency division component 2b can transmit light in the 480-650nm wavelength band. Its structure consists of six layers: the first layer is TiO2 with a thickness of 100nm, the second layer is SiO2 with a thickness of 110nm, the third layer is TiO2 with a thickness of 100nm, the fourth layer is SiO2 with a thickness of 110nm, and the fifth layer is SiO2 with a thickness of 80nm. The first layer is made of TiO2 with a thickness of 100 nm, the fourth layer is made of SiO2 with a thickness of 110 nm, the fifth layer is made of TiO2 with a thickness of 95 nm, and the sixth layer is made of SiO2 with a thickness of 35 nm. The frequency-dividing film used has good transmission characteristics (>0.9) for the available spectrum of the photovoltaic cell, which is used to achieve selective transmission of the solar spectrum. The unavailable spectrum is called the residual light spectrum. The frequency divider has good reflection characteristics (>0.9) for the residual light spectrum. The optical characteristics of the frequency-dividing component can be designed and adjusted according to the spectral response characteristics of the photovoltaic cell used. The radiation absorber component can efficiently convert light energy into heat energy with minimal loss.

[0024] like Figure 1 As shown, the electricity generated by the photovoltaic cell module is stored in the battery 5 and used to power the electrolytic reaction in the electrolysis reactor 6d. The photovoltaic cell waste heat recovery device 4b recovers the heat energy of the photovoltaic cell 4a to preheat hot water as a raw material for the thermochemical reaction, while avoiding temperature rise in the photovoltaic cell due to large amounts of radiant energy. Preferably, the photovoltaic cell 4a is a Si concentrating photovoltaic cell. High-bandgap batteries have lower power generation but higher energy in the residual light spectrum compared to low-bandgap batteries. Therefore, using low-bandgap batteries increases the electrical energy supplied to the system and enhances the concentration of the residual light spectrum, ensuring the heat energy supplied to the system meets requirements.

[0025] The three thermal storage components are a primary thermal storage component 6a that absorbs heat from the low-temperature radiation absorber 3a, a secondary thermal storage component 6b that absorbs heat from the medium-temperature radiation absorber 3b, and a tertiary thermal storage component 6c that absorbs heat from the high-temperature radiation absorber 3c. These components store a portion of the heat generated by the radiation absorbers when solar energy input is sufficient, and provide heat when solar energy input is insufficient, thus balancing the instability of solar energy and ensuring stable day and night operation of the system. Preferably, the thermal storage components use different thermal storage media depending on the temperature. The primary thermal storage component 6a operates at 130°C, the secondary thermal storage component 6b operates at 400°C, and both use heat transfer oil for thermal storage, with the main components being biphenyl and diphenyl oxide. The tertiary thermal storage component 6c operates at 530°C and uses molten salt for thermal storage, with the medium consisting of KCl and MgCl2. The power distribution ratio of the three components is 2:3:4. The heat transfer medium between the radiation absorber, the thermal storage components, and the heat exchange components is a heat transfer fluid, including but not limited to carbon dioxide and air; in this embodiment, the heat transfer fluid is air.

[0026] like Figure 1 As shown, in one embodiment of the present invention, the copper-chlorine cycle hydrogen production subsystem includes a copper-chlorine cycle hydrogen production reactor, an oxygen storage tank 7, and a hydrogen storage tank 8; wherein, the copper-chlorine cycle hydrogen production reactor includes a drying reactor 6a, a hydrolysis reactor 6b, a pyrolysis reactor 6c, and an electrolysis reactor 6d.

[0027] The drying reaction in drying reactor 6a requires a temperature of 100~130℃ to evaporate the water in the CuCl2 solution, forming solid CuCl2, which is then supplied as a raw material for the hydrolysis reaction to hydrolysis reactor 6b.

[0028] The hydrolysis reaction in hydrolysis reactor 6b requires a reaction temperature of 370~400℃, and the chemical reaction equation is: 2CuCl2(s) + H2O(g) → 2HCl(g) + Cu2OCl2(s). The product HCl gas is supplied as a raw material to electrolysis reactor 6d. The thermal equilibrium conditions required for this step are maintained by the high-concentration heat generated by the frequency-divided spectrum of the solar full-spectrum multi-stage concentrating and frequency-dividing utilization subsystem.

[0029] The pyrolysis reaction in pyrolysis reactor 6c requires a reaction temperature of 500~530℃, and the chemical reaction equation is: Cu2OCl2(s)→2CuCl(l)+0.5O2(g). The thermal equilibrium conditions required for this step are maintained by the high-temperature concentrated light energy generated by the solar full-spectrum multi-stage concentrated frequency division utilization subsystem, and the product O2 is stored in oxygen storage tank 7.

[0030] The electrolysis reaction in the electrolysis reactor for 6 days was carried out at room temperature, and the chemical reaction equation was: 2CuCl(aq) + 2HCl(g) → H2(g) + 2CuCl2(aq). The electrical energy required for this step was provided by the solar full-spectrum multi-stage concentrating and frequency-dividing utilization subsystem; the product H2 was stored in hydrogen storage tank 8.

[0031] The aforementioned thermochemical reactions constitute a complete cycle, namely the four-step copper-chlorine cycle, with the net reaction being the decomposition of water into hydrogen and oxygen. The different thermochemical reaction steps in the copper-chlorine cycle hydrogen production reactor are all endothermic reactions, and the required heat and electrical energy have different energy qualities. Utilizing the thermal energy obtained from different concentration ratios and frequency divisions, along with the electrical energy generated by photovoltaic power generation, as the energy driving the four steps in the cycle ensures that the energy input to the reaction cycle matches the energy quality required for the reaction, which is beneficial for improving the system's energy efficiency.

[0032] In one specific embodiment, the system further includes a solid-liquid material transfer system. This system transports the solid Cu₂OCl₂ and HCl gas produced in the hydrolysis reactor 6b into the pyrolysis reactor 6c and the electrolysis reactor 6d, respectively. It also transports the liquid CuCl₂ produced in the pyrolysis reaction chamber 16 into the electrolysis reactor 6d, the CuCl₂ solution produced in the electrolysis reactor 6d into the drying reactor 6a, and the solid CuCl₂ produced in the drying reactor 6a into the hydrolysis reactor 6b. The solid-liquid material transfer system recovers and transfers reusable solid and liquid products generated in each device, achieving the recycling of materials in the hydrogen production system, reducing production costs, and avoiding environmental pollution.

[0033] This application also provides a coupling method for multi-stage concentrated photovoltaic (CPV) frequency division driven copper-chlorine cycle hydrogen production, comprising the following steps: CPV modules with different concentration ratios concentrate sunlight, and the resulting concentrated beams are then divided into corresponding frequency division modules. Part of the wavelength is used by photovoltaic power generation modules to supply power for the thermochemical reaction, while the remaining wavelengths are fed into corresponding radiation absorbers to provide heat for the thermochemical reaction. The concentration ratios are ordered from low to high according to the different energy qualities required for different steps in the subsequent copper-chlorine cycle: the first stage uses a low concentration ratio of 75-85, the second stage uses a medium concentration ratio of 145-155, and the third stage uses a high concentration ratio of 245-255. The area allocation is based on the different energy requirements for different steps in the subsequent copper-chlorine cycle, with an area ratio of approximately 7:10:8. The first stage of concentration can use a trough-type concentrator, while the second and third stages can use a dish-type or tower-type concentrator depending on the scale.

[0034] In one specific embodiment, the method further includes the following steps: the drying reactor 6a uses the heat energy generated by the low-temperature radiation absorber 3a to drive the drying reaction, maintaining the temperature inside the reactor at 100~130℃; the hydrolysis reactor 6b uses the heat energy generated by the medium-temperature radiation absorber 3b to drive the hydrolysis reaction, maintaining the temperature inside the reactor at 370~400℃; the pyrolysis reactor 6c uses the heat energy generated by the high-temperature radiation absorber 3c to drive the pyrolysis reaction, maintaining the temperature inside the reactor at 500~530℃; and the electrolysis reactor 6d uses the power generated by the photovoltaic cell module 4 to drive the electrolysis reaction.

[0035] In one specific embodiment, the method further includes the following steps: the liquid CuCl product of the pyrolysis reaction is supplied to the electrolysis reactor 6d 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 reactor 6c as a raw material for the pyrolysis reaction; the solid CuCl2 product of the drying reaction is supplied to the hydrolysis reactor 6b as a product of the hydrolysis reaction; the CuCl2 solution product of the electrolysis reaction is supplied to the drying reactor 6a as a raw material for the drying reaction, and the product hydrogen leaves the circulation; the oxygen generated by the pyrolysis reaction is stored in the oxygen storage tank 7; and the hydrogen prepared by the electrolysis reaction is stored in the hydrogen storage tank 8.

[0036] In one 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. An excess of preheated hot water is introduced to ensure that the reaction proceeds fully.

[0037] The first stage uses a trough-type low-concentration photovoltaic (PTP) system with a concentration ratio of 75-85, achieving a photo-thermal conversion efficiency of 94.34% and a photo-electric conversion efficiency of 65.27% through frequency division. The second stage uses a dish-type or tower-type medium-concentration photovoltaic (PTP) system, depending on scale, with a concentration ratio of 145-155, achieving a photo-thermal conversion efficiency of 93.98% and a photo-electric conversion efficiency of 72.77% through frequency division. The third stage uses a dish-type or tower-type high-concentration photovoltaic (PTP) system, depending on scale, with a concentration ratio of 245-255, achieving a photo-thermal conversion efficiency of 93.45% through full concentration. The system's hydrogen production efficiency is 52.78%. Therefore, the system and method of this invention, based on the principle of energy quality matching, employs multi-stage frequency division to obtain electrical / thermal energy of different qualities, supplying it in stages to a thermochemical cycle for hydrogen production. This achieves complementary coupling of different energy qualities based on energy gradient conversion, providing a highly efficient solar hydrogen production pathway. Furthermore, this system converts solar energy into both electrothermal and thermal energy, matching different electrical output requirements to different thermal energy demands at different temperatures: higher electrical output for low-temperature thermal energy demands, lower electrical output for medium-temperature thermal energy demands, and thermal energy output for high-temperature thermal energy demands. This ensures that the three-stage concentrating structure maintains high solar energy conversion efficiency while requiring a concentration ratio of less than 300. Almost all commercially available concentrating structures can meet the concentration ratio requirements of this system, resulting in lower processing requirements. Moreover, it achieves full solar spectrum utilization even with a low concentration ratio, which is of great significance in practical applications.

[0038] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A three-stage concentrated frequency division driven copper-chlorine cycle hydrogen production system, characterized in that: The system includes a three-stage solar full-spectrum concentrating and frequency-dividing utilization subsystem and a copper-chlorine cycle hydrogen production subsystem. The three-stage solar full-spectrum concentrating and frequency-dividing utilization subsystem comprises a three-stage solar concentrator, two frequency-dividing components, three radiation absorbers, a photovoltaic power generation module, a battery, three thermal storage components, and three heat exchange components. The three-stage solar concentrator concentrates sunlight at three different concentration ratios. The low- and medium-concentration beams are divided by two frequency-dividing components. The usable photovoltaic wavelengths after frequency division enter the photovoltaic power generation module for photovoltaic power generation, while the remaining wavelengths enter the low-temperature and medium-temperature radiation absorbers to produce heat energy at different temperatures. The high-concentration beam directly enters the high-temperature radiation absorber to produce heat energy. The battery is used to store the electrical energy generated by the photovoltaic power generation module; The heat storage component is used to store a portion of the heat generated by the radiation absorber; the three heat exchanger components respectively utilize the thermal energy of the three radiation absorbers to heat the reactants in the copper-chlorine cycle hydrogen production reactor. The copper-chlorine cycle hydrogen production subsystem includes a copper-chlorine cycle hydrogen production reactor; the copper-chlorine cycle hydrogen production reactor includes a drying reactor, a hydrolysis reactor, a pyrolysis reactor, and an electrolysis reactor; the copper-chlorine cycle hydrogen production reactor utilizes the electrical energy generated by photovoltaic power generation components and the thermal energy generated by different radiation absorbers to carry out a four-step copper-chlorine cycle hydrogen production reaction, the net reaction of which is the decomposition of water into hydrogen and oxygen.

2. The three-stage concentrated frequency division driven copper-chlorine cycle hydrogen production system according to claim 1, characterized in that: The three-stage solar spectrum concentrator includes a first-stage low-power concentrator (1a) using trough concentrators, a second-stage medium-power concentrator (1b) using dish concentrators, and a third-stage high-power concentrator (1c) using dish concentrators. Among them, the first-stage low-concentration module (1a) provides a concentration ratio of 75 to 85 times. The resulting concentrated beam enters the low-concentration frequency division module (2a) for spectral frequency division. The photovoltaic usable band light energy is used to generate electricity for the photovoltaic power generation module, and the remaining band light energy enters the low-temperature radiation absorber (3a) to provide heat for the drying reaction in the drying reactor (6a) which requires low-temperature thermal energy. The second-stage medium-multiplexing photovoltaic module (1b) provides a concentration multiple of 145~155 times. The resulting concentrated beam enters the medium-multiplexing frequency divider module (2b) for spectral frequency division. The photovoltaic usable wavelength band light energy is used for photovoltaic cell power generation, and the remaining wavelength band light energy enters the medium-temperature radiation absorber (3b) to provide heat for the hydrolysis reaction in the hydrolysis reactor (6b). The third-stage high-concentration module (1c) provides a concentration factor of 245 to 255 times, and the resulting concentrated beam enters the high-temperature radiation absorber (3c) to provide heat for the pyrolysis reaction in the pyrolysis reactor (6c). The electricity generated by the photovoltaic cell module is stored in a battery and used to power the electrolysis reaction in the electrolysis reactor (6d); the photovoltaic power generation module has a photovoltaic cell waste heat utilization device (4b), which recovers the heat energy of the photovoltaic power generation module to preheat hot water as a raw material for the copper-chlorine cycle reaction.

3. The three-stage concentrated frequency division driven copper-chlorine cycle hydrogen production system according to claim 1, characterized in that: The three thermal storage components are used to store part of the heat generated by the three radiation absorbers when solar energy input is sufficient, and to provide heat when solar energy input is insufficient, in order to balance the instability of solar energy and ensure stable operation of the system day and night.

4. The three-stage concentrated frequency division driven copper-chlorine cycle hydrogen production system according to claim 1, characterized in that: The drying reaction in the drying reactor (8a) requires a temperature of 100~130℃. The drying reactor is powered by a low-temperature radiation absorber and is used to evaporate the water in the CuCl2 solution to form solid CuCl2, which is then supplied as a raw material for the hydrolysis reactor (8b). The hydrolysis reaction in the hydrolysis reactor (8b) requires a reaction temperature of 370~400℃, and the chemical reaction equation is: 2CuCl2+H2O→2HCl+Cu2OCl2; the product HCl gas is supplied as a raw material for the electrolysis reaction to the electrolysis reactor (8d); the hydrolysis reaction is powered by a medium-temperature radiation absorber. The pyrolysis reaction in the pyrolysis reactor (8c) requires a reaction temperature of 500~530℃, powered by a high-temperature radiation absorber. The chemical reaction equation is: Cu2OCl2→2CuCl+0.5O2; The electrolysis reaction in the electrolysis reactor (8d) was carried out at room temperature, and the chemical reaction equation was: 2CuCl + 2HCl → H2 + 2CuCl2.

5. The three-stage concentrated frequency division driven copper-chlorine cycle hydrogen production system according to claim 2, characterized in that: The three heat exchange components are a low-temperature thermal oil heat exchanger (7a), a medium-temperature thermal oil heat exchanger (7b), and a high-temperature molten salt heat exchanger (7c). The low-temperature molten salt heat exchanger (7a) is used to input the heat from the low-temperature thermal storage component (6a) into the drying reactor (8a) to provide the energy required for the reaction and maintain the operating temperature; the medium-temperature thermal oil heat exchanger (7b) is used to input the heat from the medium-temperature thermal storage component (6b) into the hydrolysis reactor (8b) to provide the energy required for the reaction and maintain the operating temperature; and the high-temperature molten salt heat exchanger (7c) is used to input the heat from the high-temperature thermal storage component (6c) into the pyrolysis reactor (8c) to provide the energy required for the reaction and maintain the operating temperature.

6. The three-stage concentrated frequency division driven copper-chlorine cycle hydrogen production system as described in claim 4, characterized in that: The system also includes a solid-liquid material transport system, which transports the solid Cu2OCl2 and HCl gas generated in the hydrolysis reactor (8b) into the pyrolysis reactor (8c) and the electrolysis reactor (8d) respectively, transports the liquid CuCl generated in the pyrolysis reactor (8c) into the electrolysis reactor (8d), transports the CuCl2 solution generated in the electrolysis reactor (8d) into the drying reactor (8a), and transports the solid CuCl2 generated in the drying reactor (8a) into the hydrolysis reactor (8b).

7. The three-stage concentrated frequency division driven copper-chlorine cycle hydrogen production system according to claim 1, characterized in that: The two frequency division components are a low-concentration frequency division component (2a) and a medium-concentration frequency division component (2b). Both are optical interference multilayer frequency division films formed by alternating deposition of TiO2 and SiO2 materials on a transparent substrate. The low-concentration frequency division component (2a) transmits a portion of the wavelength band of 420nm~710nm to the photovoltaic power generation component below for power generation, and the remaining wavelength band enters the low-temperature radiation absorber (3a) to be converted into heat energy. The medium-concentration frequency division component (2b) transmits a portion of the wavelength band of 480nm~650nm to the photovoltaic power generation component below for power generation, and the remaining wavelength band enters the medium-temperature radiation absorber (3b) to be converted into heat energy.

8. The three-stage concentrated frequency division driven copper-chlorine cycle hydrogen production system according to claim 1, characterized in that: The low-temperature radiation absorber (3a) provides heat energy at 130°C, the medium-temperature radiation absorber (3b) provides heat energy at 370~400°C, and the high-temperature radiation absorber (3c) provides heat energy at 500~530°C.

9. The three-stage concentrated frequency division driven copper-chlorine cycle hydrogen production system according to claim 8, characterized in that: The three heat storage components are a primary heat storage component (6a) that absorbs heat from a low-temperature radiation absorber (3a), a secondary heat storage component (6b) that absorbs heat from a medium-temperature radiation absorber (3b), and a tertiary heat storage component (6c) that absorbs heat from a high-temperature radiation absorber (3c). The primary heat storage component (6a) operates at a temperature of 130°C, the secondary heat storage component (6b) operates at a temperature of 400°C and both use heat transfer oil for heat storage, and the tertiary heat storage component (6c) operates at a temperature of 530°C and uses molten salt for heat storage. The heat transfer medium between the radiation absorber, the heat storage component, and the heat exchange component is a heat transfer fluid.

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