Solar radiation energy grading and residual light energy thermal complementary coupling electric / thermal chemical step hydrogen production system and method

Abstract

The application provides a solar radiation energy grading and residual light energy thermal complementary coupling electric / thermal chemical step hydrogen production system and method, the system comprises a light collecting assembly; a frequency separation assembly for solar spectrum radiation grading; a photovoltaic cell power generation device; a methane oxygen-enriched combustion high-temperature photovoltaic power generation device for realizing natural gas oxygen-enriched combustion by using residual light thermal energy and generating electricity by using the radiation energy generated by high-temperature flue gas generated after combustion; a solid oxide electrolysis cell device for gradually using the thermal energy and electric energy contained in the high-temperature flue gas to drive solid oxide water electrolysis hydrogen production; and a thermochemical reaction device for gradually using the thermal energy and electric energy contained in the high-temperature flue gas to drive each step of thermochemical reaction. The energy source of the system is solar radiation and natural gas, the output is hydrogen and electricity, and the system realizes the temperature step ordered conversion and utilization of the residual light energy after solar energy frequency separation by using different energy conversion modes, and realizes the complementary coupling of different qualities on the basis of energy step conversion.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of new energy preparation, and particularly relates to a solar radiation energy grading and residual light energy thermal complementary coupled electric / thermal chemical step hydrogen production system and method. BACKGROUND

[0002] Due to the advantages of solar energy such as cleanness, sustainability and huge energy, solar energy is regarded as an important direction for future energy development. However, due to the objective discontinuity, there is a large-scale light abandonment problem, and the medium and low grade solar energy cannot be effectively utilized, so that the solar energy utilization and conversion efficiency is difficult to improve. Hydrogen energy is a high-calorific value and pollution-free secondary energy, and it is a very promising energy utilization mode to store and utilize hydrogen energy by converting solar energy into hydrogen energy through water splitting, and it is also considered as one of the most ideal hydrogen production ways in the future. Photovoltaic power generation is a high-efficiency photoelectric conversion mode, but photovoltaic cells can only convert high-grade solar energy in a specific wavelength range into electric energy, and a large amount of solar energy is wasted. The spectral splitting technology can decompose solar radiation energy into different wave bands, so that each wave band can be effectively utilized. The high-grade solar radiation energy is directly converted into electric energy by photovoltaic power generation, and the low-grade residual wave band energy can be complemented with fossil fuels to greatly improve the energy grade. However, there is still a lack of a single way to fully and efficiently utilize high-grade heat energy, so the energy gradient conversion and utilization is a scientific and effective way.

[0003] In the hydrogen production technology, the water splitting by solid oxide electrolysis cell and the hydrogen production by copper-chlorine cycle are both clean and efficient hydrogen production methods, and there is no greenhouse gas emission in the hydrogen production process, and different grades of heat energy and electric energy are needed. The difference is that the water electrolysis by solid oxide electrolysis cell needs to maintain a high temperature environment of 700-800 DEG C, while the highest temperature required in the copper-chlorine cycle is only 530 DEG C. The energy required by the two can be matched with the solar radiation energy grading and residual light energy thermal complementary step conversion utilization mode (power generation and heat supply), realizing the coupling of different quality energy and providing a high-efficiency solar hydrogen production way. SUMMARY

[0004] In view of the above technical status, the application aims to provide a solar radiation energy grading and residual light energy thermal complementary coupled electric / thermal chemical step hydrogen production system and method, which utilizes natural sunlight by frequency division, directly generates electricity by photovoltaic power generation with high-grade sunlight, complements and improves the energy grade with low-grade residual light and natural gas, and utilizes different energy conversion modes to realize the ordered temperature gradient conversion and utilization of residual light and match and couple solid oxide fuel cells and copper-chlorine cycle, so as to efficiently output hydrogen energy and greatly improve the energy utilization efficiency.

[0005] In one aspect, the application provides a solar radiation energy grading and residual light energy thermal complementary coupled electric / thermal chemical step-by-step hydrogen production system, comprising a light collecting assembly, a frequency dividing assembly, a photovoltaic power generation device, a methane oxygen-enriched combustion high-temperature photovoltaic power generation device, a solid oxide electrolysis cell device, and a thermal chemical reaction device;

[0006] The light collecting assembly collects sunlight, and the frequency dividing assembly divides the frequency of the collected light beam, wherein the frequency suitable for photovoltaic power generation is reflected to the photovoltaic power generation device for photovoltaic power generation, and the remaining frequency is twice collected by the light collecting assembly to the methane oxygen-enriched combustion high-temperature photovoltaic power generation device;

[0007] The methane oxygen-enriched combustion high-temperature photovoltaic power generation device converts the twice collected sunlight into heat energy by using a tubular receiver to preheat the oxygen-enriched air, and the preheated oxygen-enriched air is input into a combustion chamber together with natural gas for oxygen-enriched combustion to generate first-stage high-temperature flue gas, and the methane oxygen-enriched combustion high-temperature photovoltaic power generation device uses the radiant energy of the first-stage high-temperature flue gas for photovoltaic power generation, and the second-stage high-temperature flue gas is discharged from the combustion chamber to the solid oxide electrolysis cell device;

[0008] The solid oxide electrolysis cell device uses a three-stage heat exchanger and a solid oxide electrolysis cell to gradually use the heat of the high-temperature flue gas, wherein the solid oxide electrolysis cell uses the electric energy generated by the system and the heat contained in the high-temperature flue gas for high-temperature electrolysis to produce hydrogen, and discharges fourth-stage high-temperature flue gas to supply the thermal chemical circulation device;

[0009] The pyrolysis reaction bin, hydrolysis reaction bin, and drying reaction bin of the thermal chemical circulation device gradually use the heat energy contained in the high-temperature flue gas to drive the reaction, and the entire thermal chemical circulation device uses the heat energy contained in the high-temperature flue gas and the electric energy generated by the system to realize copper-chlorine cycle to produce hydrogen.

[0010] In particular, by adjusting the proportion of air and oxygen entering the tubular receiver, i.e., adjusting the oxygen content in the oxygen-enriched air, the instability of solar energy is balanced to ensure that the system operates self-sustainably day and night.

[0011] In another aspect, the application also provides a solar radiation energy grading and residual light energy thermal complementary coupled electric / thermal chemical step-by-step hydrogen production method, specifically comprising the following steps: natural sunlight is once collected and then reaches the frequency dividing assembly, the reflected light beam is efficiently used by the photovoltaic power generation device, the remaining sunlight is transmitted, and the remaining sunlight is twice collected and then reaches the tubular receiver;

[0012] The oxygen-enriched air is preheated by concentrated solar residual light in a tubular receiver and is burned with natural gas in a combustion chamber to produce first-stage high-temperature flue gas with a temperature of 2000-2500℃; the methane oxygen-enriched 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℃ to generate heat photovoltaic power, which is converted into second-stage high-temperature flue gas with a temperature of 850-1000℃ and is fed into the solid oxide electrolysis cell device;

[0013] The solid oxide electrolysis cell device uses the thermal energy contained in the second-stage high-temperature flue gas with a temperature of 850-1000℃ to heat the electrolysis reaction raw material through the third-stage heat exchanger, which is converted into third-stage high-temperature flue gas with a temperature of 750-850℃ and is fed into the solid oxide electrolysis cell; the solid oxide electrolysis cell uses the third-stage high-temperature flue gas with a temperature of 750-850℃ and the electric energy generated by the system photovoltaic power generation to drive the solid oxide electrolysis water to produce hydrogen, which is converted into fourth-stage high-temperature flue gas with a temperature of 530-680℃ and is fed into the thermochemical reaction device;

[0014] In the thermochemical reaction device, the pyrolysis reaction bin uses the thermal energy contained in the fourth-stage high-temperature flue gas to drive the pyrolysis reaction, which is converted into fifth-stage high-temperature flue gas with a temperature of 400-460℃ and is fed into the hydrolysis reaction bin; the hydrolysis reaction bin uses the thermal energy contained in the fifth-stage high-temperature flue gas to drive the hydrolysis reaction, which is converted into sixth-stage high-temperature flue gas with a temperature of 130-200℃ and is fed into the drying reaction bin; the drying reaction bin uses the thermal energy contained in the sixth-stage high-temperature flue gas to drive the drying reaction, which is converted into low-temperature flue gas and is discharged; the electrolysis reaction bin uses the electric energy generated by the system photovoltaic power generation to perform electrolysis reaction to produce hydrogen.

[0015] The system and method proposed in the present application have the following advantages or beneficial effects:

[0016] 1. The photovoltaic conversion and photothermal conversion are decoupled by concentrating and frequency dividing, the hierarchical utilization of solar radiation energy is realized, and the energy utilization efficiency is improved.

[0017] 2. The low-grade solar residual light is complementary to natural gas, the first-stage high-temperature flue gas with a temperature of 2000-2500℃ is obtained by oxygen-enriched combustion, and the energy grade is effectively improved.

[0018] 3. Based on the principle of energy quality matching, high-grade solar energy is directly used for photovoltaic power generation, high-temperature heat photovoltaic power generation is performed using the first-stage high-temperature flue gas; different quality electric / thermal energy is supplied to the solid oxide high-temperature electrolysis reaction and the thermochemical cycle to produce hydrogen in stages, and the complementary coupling of different qualities is realized on the basis of energy cascade conversion.

[0019] 4. Oxygen produced by electrolysis reaction and pyrolysis reaction can be used to provide raw material for oxygen-enriched combustion, and the oxygen content in oxygen-enriched air is adjusted to balance the instability of solar energy, so as to ensure stable operation of the system day and night.

[0020] 5. A heat recovery device is added in the system, and the released heat in the system is maximized by reasonable design and layout, so that the energy loss of the system is effectively reduced.

[0021] 6. The cathode material can be effectively prevented from being oxidized under high temperature and high humidity conditions by introducing appropriate amount of hydrogen into the cathode of the solid oxide electrolysis cell. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a schematic diagram of a solar radiation energy grading and residual light energy thermal complementary coupling electro / thermal chemical cascade hydrogen production system structure according to an embodiment of the present application;

[0023] 1- primary light focusing assembly, 2- frequency division assembly, 3- secondary light focusing assembly, 4- first-stage photovoltaic cell, 5- first-stage photovoltaic cell waste heat utilization device, 6- tubular receiver, 7- combustion chamber, 8- emitter, 9- filter, 10- second-stage photovoltaic cell, 11- second-stage photovoltaic cell waste heat utilization device, 12- first-stage heat exchanger, 13- second-stage heat exchanger, 14- third-stage heat exchanger, 15- solid oxide electrolysis cell, 16- pyrolysis reaction bin, 17- hydrolysis reaction bin, 18- drying reaction bin, 19- electrolysis reaction bin, 20- hydrogen storage tank, 21- oxygen storage tank, 22- hydrogen separator, 23- battery. DETAILED DESCRIPTION

[0024] In order to better understand the technical solutions of the present application, the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0025] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, and are intended to explain the inventive concept. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0026] Unless otherwise explicitly specified and limited, the terms "high temperature", "low temperature" and the like used in the description are only used to describe relative characteristics, and do not indicate or imply that the technical features referred to must have a specific index.

[0027] Unless otherwise explicitly specified and limited, the terms "one", "two", "primary", "secondary" and the like used in the description are only used for descriptive purposes to facilitate the differentiation of the purpose of the different similar components or devices, and cannot be understood as indicating or implying relative importance or implicitly indicating the technical features indicated.

[0028] Unless otherwise explicitly specified and limited, the terms "connected", "connected" and the like used in the description should be broadly understood, for example, it can be fixed connection, detachable connection, or integral; it can be mechanical connection, electrical connection; it can be directly connected, indirectly connected through intermediate medium; it can be internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments can be understood according to the specific circumstances.

[0029] The embodiment of the present application provides a solar radiation energy grading and residual light energy heat complementary coupled electric / thermal chemical step hydrogen production system, and a method for step hydrogen production using the system.

[0030] Referring to Figure 1 In one specific embodiment of the present application, a solar radiation energy grading and residual light energy heat complementary coupled electric / thermal chemical step hydrogen production system is provided, comprising a light condensing assembly, a frequency dividing assembly 2, a photovoltaic power generation device, a methane oxygen-enriched combustion high-temperature photovoltaic power generation device, a solid oxide electrolysis cell device and a thermochemical reaction device; wherein the light condensing assembly condenses sunlight, and the frequency dividing assembly 2 divides the frequency of the condensed light beam, wherein the frequency band suitable for photovoltaic power generation is reflected to the photovoltaic power generation device for photovoltaic power generation, and the remaining frequency band is twice condensed by the light condensing assembly to the methane oxygen-enriched combustion high-temperature photovoltaic power generation device;

[0031] The methane oxygen-enriched combustion high-temperature photovoltaic power generation device converts the twice condensed sunlight into heat energy by using a tubular receiver 6 to preheat the oxygen-enriched air, and the preheated oxygen-enriched air is input into a combustion chamber 7 with natural gas for oxygen-enriched combustion to generate first-stage high-temperature flue gas; the methane oxygen-enriched combustion high-temperature photovoltaic power generation device uses the radiant energy of the first-stage high-temperature flue gas for photovoltaic power generation, and the second-stage high-temperature flue gas is discharged from the combustion chamber 7 to the solid oxide electrolysis cell device;

[0032] The solid oxide electrolysis cell device uses a three-stage heat exchanger 14 and a solid oxide electrolysis cell 15 to gradually use the heat of the high-temperature flue gas, wherein the solid oxide electrolysis cell 15 uses the electric energy generated by the system and the heat contained in the high-temperature flue gas for high-temperature electrolysis to produce hydrogen, and discharges fourth-stage high-temperature flue gas to supply the thermochemical cycle device;

[0033] The pyrolysis reaction chamber 16, hydrolysis reaction chamber 17 and drying reaction chamber 18 of the thermochemical cycle device utilize the heat energy contained in the high-temperature flue gas to drive the reaction in stages. The entire thermochemical cycle device uses the heat energy contained in the high-temperature flue gas and the electrical energy generated by the system to realize the copper-chlorine cycle and produce hydrogen.

[0034] like Figure 1 As shown, the system of the present invention has an air / flue gas pipeline for heat transfer, which is sequentially connected to a tubular receiver 6, a combustion chamber 7, a heat exchanger 14, a solid oxide electrolysis cell 15, a pyrolysis reaction chamber 16, a hydrolysis reaction chamber 17, and a drying reaction chamber 18, so as to realize the energy cascade conversion of high-temperature flue gas and the mutual coupling between systems.

[0035] In one specific embodiment of the present invention, the concentrating component includes a primary concentrating component 1 and a secondary concentrating component 3 for enhancing solar radiation intensity; the primary concentrating component 1 focuses natural sunlight onto a frequency divider component 2; the secondary concentrating component 3 focuses the residual light after frequency division onto a tubular receiver 6. Preferably, the primary concentrating component 1 and the secondary concentrating component 3 are point-focusing Fresnel concentrating components, which are mature products and inexpensive.

[0036] The frequency divider 2 of this invention is used to reflect the first beam of light that can be efficiently utilized by photovoltaic cells, and transmit the remaining solar afterglow to the secondary concentrator 3. The solar spectrum is divided into two parts according to photon energy for different energy-efficient conversion pathways. Preferably, the frequency divider is made of multilayer polymer or semiconductor stacked nanofilm. By adjusting the position of the frequency divider, the specific wavelengths of the first beam and the solar afterglow can be controlled.

[0037] In one embodiment of the present invention, the photovoltaic power generation device includes a primary photovoltaic cell 4 and a primary photovoltaic cell waste heat utilization device 5. The primary photovoltaic cell 4 is used to receive a first beam of light for photovoltaic power generation, providing electrical energy for subsequent electrolytic hydrogen production. The primary photovoltaic cell waste heat utilization device 5 recovers the heat energy of the primary photovoltaic cell 4 for preheating hot water, obtaining hot water at a temperature of 40-60°C as raw material for the pyrolysis reaction in the thermochemical cycle, while avoiding the temperature rise of the photovoltaic cell due to a large amount of radiant energy. Preferably, the primary photovoltaic cell waste heat utilization device 5 is provided with an inlet for cold water and an outlet for hot water. Preferably, the primary photovoltaic cell 4 is a gallium arsenide (GaAs) photovoltaic cell with a cutoff wavelength of 900nm. This type of photovoltaic cell has high photoelectric conversion efficiency, can withstand high temperature and high concentration ratio light, and better meets the system requirements.

[0038] In one embodiment of the present application, the methane oxygen-rich combustion high-temperature photovoltaic power generation device comprises a tubular receiver 6, a combustion chamber 7, an emitter 8, a filter 9, a secondary photovoltaic cell 10 and a secondary photovoltaic cell waste heat utilization device 11. A photo-thermal absorber is fixed in the tubular receiver 6, which absorbs the sunlight focused by the secondary light focusing assembly 3 to convert the sunlight into heat energy, preheats the oxygen-rich air, generates oxygen-rich air with a temperature of 600-700℃, and inputs the oxygen-rich air and natural gas into the combustion chamber 7 for oxygen-rich combustion to generate first-stage high-temperature flue gas with a temperature of 2000-2500℃. The first-stage high-temperature flue gas generates radiation energy through the emitter 8, the radiation energy selectively passes through the filter 9, and is absorbed by the secondary photovoltaic cell 10 to generate electric energy. The radiation energy that does not match the secondary photovoltaic cell returns to the combustion chamber 7, and then the first-stage high-temperature flue gas is converted into second-stage high-temperature flue gas with a temperature of 850-1000℃, which is discharged from the combustion chamber 7 to supply the third heat exchanger 14 of the solid oxide electrolysis cell device. The secondary photovoltaic cell waste heat utilization device 11 recovers the heat energy of the secondary photovoltaic cell 10 to preheat water, obtains hot water with a temperature of 40-60℃ as raw material for pyrolysis reaction in thermochemical cycle, improves energy utilization efficiency, and avoids temperature rise of the photovoltaic cell due to a large amount of radiation energy. Preferably, the tubular receiver 6 is provided with an air inlet, an oxygen inlet and an outlet for discharging preheated oxygen-rich air, the oxygen inlet is connected with the outlet of the oxygen storage tank 21; the combustion chamber 7 is provided with an oxygen-rich air inlet and an outlet for discharging second-stage high-temperature flue gas, the oxygen-rich air inlet is connected with the oxygen-rich air outlet of the tubular receiver 6; the secondary photovoltaic cell waste heat utilization device 11 is provided with an inlet for cold water and an outlet for hot water. Preferably, the secondary photovoltaic cell 10 adopts a gallium antimonide (GaSb) photovoltaic cell with a cutoff wavelength of 1800nm, which can withstand higher intensity of thermal radiation and is more suitable for the system requirements.

[0039] In one embodiment of the present application, the solid oxide electrolysis cell device comprises a first heat exchanger 12, a second heat exchanger 13, a third heat exchanger 14 and a solid oxide electrolysis cell 15, and the high-temperature electrolysis at 700-800℃ is realized by using the heat energy contained in the second-stage high-temperature flue gas and the third-stage high-temperature flue gas after heat exchange in the third heat exchanger 14 and the electric energy, and the gradual increase of the temperature and the phase change of the raw material (water) are realized by recovering the heat, so that the energy utilization efficiency is improved. The first heat exchanger 12 is used to recover the heat of the high-temperature hydrogen gas and the water vapor discharged from the cathode of the solid oxide electrolysis cell 15, so as to further heat the hot water (~60℃) discharged from the second-stage photovoltaic cell waste heat utilization device 11; the second heat exchanger 13 is used to recover the heat of the high-temperature oxygen gas discharged from the anode of the solid oxide electrolysis cell 15, so as to further heat the hot water vapor discharged from the first heat exchanger 12; the third heat exchanger 14 is used to further heat the hot water vapor discharged from the second heat exchanger 13 by using the heat contained in the second-stage high-temperature flue gas with a temperature of 850-1000℃, and the high-temperature water vapor (700-800℃) after heating is introduced into the cathode of the solid oxide electrolysis cell 15 as the raw material for electrolysis reaction, and the third-stage high-temperature flue gas with a temperature of 750-850℃ after heat exchange in the third heat exchanger 14 is supplied to the solid oxide electrolysis cell 15; the solid oxide electrolysis cell 15 is used to produce hydrogen by high-temperature electrolysis by using the electric energy generated by the photovoltaic cell and the heat contained in the third-stage high-temperature flue gas, and the required electric energy is provided by the storage battery 23, and the high-temperature hydrogen gas and the high-temperature water vapor not subjected to electrolysis are produced at the cathode, and the high-temperature oxygen gas is produced at the anode, and the fourth-stage high-temperature flue gas with a temperature of 530-680℃ after heat exchange in the solid oxide electrolysis cell 15 is supplied to the thermochemical cycle device.

[0040] Preferably, the hot water / water vapor pipeline is sequentially connected to the first heat exchanger 12, the second heat exchanger 13, the third heat exchanger 14 and the solid oxide electrolysis cell 15; the inlet of the high-temperature hydrogen gas and water vapor mixed gas introduced into the first heat exchanger 12 is connected to the cathode outlet of the solid oxide electrolysis cell 15, and the inlet of the hot water is connected to the hot water outlet of the second-stage photovoltaic cell waste heat utilization device 11; the inlet of the high-temperature oxygen gas introduced into the second heat exchanger 13 is connected to the anode outlet of the solid oxide electrolysis cell 15, and the inlet of the hot water vapor is connected to the hot water vapor outlet of the first heat exchanger 12; the inlet of the second-stage high-temperature flue gas introduced into the third heat exchanger 14 is connected to the high-temperature flue gas outlet of the combustion chamber 7, and the inlet of the hot water vapor is connected to the hot water vapor outlet of the second heat exchanger 13; the solid oxide electrolysis cell 15 is provided with an inlet of the third-stage high-temperature flue gas and an outlet of the fourth-stage high-temperature flue gas, the inlet of the third-stage high-temperature flue gas is connected to the high-temperature flue gas outlet of the third heat exchanger 14, the cathode is provided with an inlet of the high-temperature water vapor, an inlet of the hydrogen gas and an outlet of the high-temperature hydrogen gas and water vapor, the inlet of the high-temperature water vapor is connected to the high-temperature water vapor outlet of the third heat exchanger 14, and the anode is provided with an outlet of the high-temperature oxygen gas.

[0041] Further preferably, the solid oxide electrolysis cell device is further provided with a hydrogen separator 22, which is used to separate hydrogen and water in the mixed gas at the outlet of the first heat exchanger 12, the separated water is used to cool the photovoltaic power generation device, and part of the separated hydrogen is supplied to the cathode of the solid oxide electrolysis cell 15, which effectively prevents the oxidation of the cathode material under high temperature and high humidity conditions.

[0042] In one embodiment of the present application, the thermo-chemical reaction device comprises a pyrolysis reaction bin 16, a hydrolysis reaction bin 17, a drying reaction bin 18, and an electrolysis reaction bin 19. The pyrolysis reaction bin 16 utilizes the heat contained in the fourth-stage high-temperature flue gas to drive the pyrolysis reaction, so that the temperature in the pyrolysis reaction bin is maintained at 500-530°C, and the fourth-stage high-temperature flue gas is converted into fifth-stage high-temperature flue gas with a temperature of 400-460°C to supply the hydrolysis reaction bin 17 after heat exchange; the chemical reaction equation of the pyrolysis reaction is Cu2OCl2(s)→2CuCl(l)+0.5O2(g). The hydrolysis reaction bin 17 utilizes the heat contained in the fifth-stage high-temperature flue gas to drive the hydrolysis reaction, so that the temperature in the hydrolysis reaction bin is maintained at 370-400°C, and the fifth-stage high-temperature flue gas is converted into sixth-stage high-temperature flue gas with a temperature of 130-200°C to supply the drying reaction bin 18 after heat exchange; the chemical reaction equation of the hydrolysis reaction is 2CuCl2(s)+H2O(g)→2HCl(g)+Cu2OCl2(s), and the product HCl gas is used as raw material for the electrolysis reaction to supply the electrolysis reaction bin 19. The drying reaction bin 18 utilizes the heat contained in the sixth-stage high-temperature flue gas to drive the drying reaction, so that the water in the CuCl2 solution is evaporated to form solid CuCl2, and the temperature in the drying reaction bin is maintained at 100-130°C, and the sixth-stage high-temperature flue gas is converted into low-temperature flue gas to be discharged after heat exchange. The electrolysis reaction bin 19 utilizes part of the electricity generated by the photovoltaic cell stored in the battery 22 to drive the electrolysis reaction, and the chemical reaction equation is 2CuCl(aq)+2HCl(g)→H2(g)+2CuCl2(aq). The thermo-chemical reaction constitutes a complete cycle, i.e., a four-step copper-chlorine cycle, and the net reaction is water splitting into hydrogen and oxygen. The thermo-chemical reaction device utilizes the heat energy contained in the fourth, fifth, and sixth-stage high-temperature flue gases and part of the electricity generated by the photovoltaic cell in sequence to meet the different reaction temperature conditions and the required energy types, which is conducive to the full reaction and the effective utilization of energy in a cascade manner. Preferably, the fourth-stage high-temperature flue gas inlet of the pyrolysis reaction bin 16 is connected with the high-temperature flue gas outlet of the heat exchanger 8, the fifth-stage high-temperature flue gas inlet of the hydrolysis reaction bin 17 is connected with the high-temperature flue gas outlet of the pyrolysis reaction bin 16, and the sixth-stage high-temperature flue gas inlet of the drying reaction bin 18 is connected with the high-temperature flue gas outlet of the hydrolysis reaction bin 17.

[0043] In a specific embodiment, the system of the present application further comprises a solid-liquid material transfer system, through which the solid Cu2OCl2 and HCl gas produced in the hydrolysis reaction tank 17 are respectively transported into the pyrolysis reaction tank 16 and the electrolysis reaction tank 19, the liquid CuCl produced in the pyrolysis reaction tank 16 is transported into the electrolysis reaction tank 19, the CuCl2 solution produced in the electrolysis reaction tank 19 is transported into the drying reaction tank 18, and the CuCl2 solid produced in the drying reaction tank 18 is transported into the hydrolysis reaction tank 17. The solid-liquid material transfer system recycles and transports the reusable solid-liquid products produced in each device, realizes the recycling of materials in the hydrogen production system, reduces the production cost, and avoids pollution to the environment.

[0044] As shown in Figure 1 The system of the present application further comprises a hydrogen storage tank 20, an oxygen storage tank 21, and a battery 22; wherein the hydrogen storage tank 20 and the oxygen storage tank 21 are respectively used to store the hydrogen and oxygen produced by the SOEC electrolysis of water and the thermochemical cycle; the hydrogen storage tank 20 is connected with the hydrogen separator 22 and the hydrogen outlet of the electrolysis reaction tank 19, and the oxygen storage tank 21 is connected with the secondary heat exchanger 13 and the oxygen outlet of the pyrolysis reaction tank 16; the battery 22 is used to store the electric energy generated by the photovoltaic cells and is connected with the primary photovoltaic cells 4 and the secondary photovoltaic cells 10.

[0045] The embodiment of the present application also provides a solar radiation energy grading and residual light energy thermal complementary coupling electric / thermal chemical step hydrogen production method, which specifically comprises the following steps: natural sunlight is concentrated once and reaches a frequency division component 2, reflected light beams with high efficiency used by photovoltaic cells reach a photovoltaic power generation device, and the rest of the wave band of sunlight is transmitted, and the rest of the light is concentrated twice and reaches a tubular receiver 6, and the power generated by the photovoltaic power generation device is stored in a storage battery 23; oxygen-rich air is preheated by concentrated sunlight and enters a combustion chamber 7 together with natural gas to be combusted, so that first-stage high-temperature flue gas with a temperature of 2000-2500℃ is generated; the high-temperature photovoltaic power generation device utilizes the radiation energy contained in the first-stage high-temperature flue gas to generate heat and converts the heat into second-stage high-temperature flue gas with a temperature of 700-1000℃, which is introduced into the solid oxide electrolysis cell device, and the power generated is stored in the storage battery 23; the third-stage heat exchanger 14 utilizes the heat energy contained in the second-stage high-temperature flue gas to heat the electrolysis reaction raw material to 700-800℃, and converts the heat into third-stage high-temperature flue gas with a temperature of 750-850℃, which is introduced into the solid oxide electrolysis cell device; the solid oxide electrolysis cell 15 utilizes the third-stage high-temperature flue gas and a part of the electric energy stored in the storage battery 23 to drive the SOEC to electrolyze water to produce hydrogen, and converts the hydrogen into fourth-stage high-temperature flue gas with a temperature of 530-680℃, which is introduced into a pyrolysis reaction bin 16, so that the temperature in the solid oxide electrolysis cell 15 is maintained at 700-800℃; the pyrolysis reaction bin 16 utilizes the heat energy contained in the fourth-stage high-temperature flue gas to drive a pyrolysis reaction, and converts the heat into fifth-stage high-temperature flue gas with a temperature of 400-460℃, which is introduced into a hydrolysis reaction bin 17, so that the temperature in the pyrolysis reaction bin 16 is maintained at 500-530℃; the hydrolysis reaction bin 17 utilizes the heat energy contained in the fifth-stage high-temperature flue gas to drive a hydrolysis reaction, and converts the heat into sixth-stage high-temperature flue gas with a temperature of 130-200℃, which is introduced into a drying reaction bin 18, so that the temperature in the hydrolysis reaction bin 17 is maintained at 370-400℃; the drying reaction bin 18 utilizes the heat energy contained in the sixth-stage high-temperature flue gas to drive a drying reaction, and converts the heat into low-temperature flue gas, which is discharged, so that the temperature in the drying reaction bin 18 is maintained at 100-130℃.

[0046] In a specific embodiment, the method further comprises the following steps: the liquid product CuCl of the pyrolysis reaction is supplied to the electrolysis reaction bin 19 as the raw material of the electrolysis reaction, and the product oxygen is discharged from the cycle; the solid product Cu2OCl2 of the hydrolysis reaction is supplied to the pyrolysis reaction bin 16 as the raw material of the pyrolysis reaction; the product CuCl2 of the drying reaction is supplied to the hydrolysis reaction bin 17 as the product of the hydrolysis reaction; the product CuCl2 solution of the electrolysis reaction is supplied to the drying reaction bin 18 as the raw material of the drying reaction, and the product hydrogen is discharged from the cycle.

[0047] In a specific embodiment, the method further comprises the following steps: hydrogen is produced by electrolysis reaction in the electrolysis reaction chamber 19 using part of the electrical energy stored in the battery 23, and the produced hydrogen is stored in the hydrogen storage tank 20; the oxygen produced in the pyrolysis reaction chamber 16 is stored in the oxygen storage tank 21, and part of the oxygen is mixed with air to form oxygen-enriched air in the tubular receiver 6; by adjusting the proportion of air and oxygen entering the tubular receiver 6, that is, adjusting the oxygen content in the oxygen-enriched air, the instability of solar energy is balanced to ensure the stable operation of the system day and night.

[0048] In a specific embodiment, the method further comprises the following steps: the hydrogen separator 22 separates the hydrogen and water in the mixed gas at the outlet of the first heat exchanger 12, the separated water is mixed with the cooling water newly input into the system and flows into the first photovoltaic cell waste heat utilization device 5, and part of the separated hydrogen is supplied to the cathode of the solid oxide electrolysis cell 15; and an appropriate amount of hydrogen can effectively prevent the cathode material from being oxidized under high temperature and high humidity conditions.

[0049] In a specific embodiment, the required electrical / thermal ratio of the solid oxide electrolysis cell for producing hydrogen is about 2 (under the condition of 800℃), the four-step copper-chlorine cycle requires thermal energy of 349.96 kJ / (mol H2) and electrical energy of 57.76 kJ / (mol H2), and excess preheated hot water is introduced to ensure that the reaction proceeds sufficiently. In order to ensure safety, the temperature of the concentrated solar preheated oxygen-enriched air does not exceed 700℃, and the natural gas feed power is 15 kW. The power of the photovoltaic power generation device is 1.03 kW, the power of the high-temperature photovoltaic power generation device produced by methane oxygen-enriched combustion is 7.48 kW; the hydrogen production power of the solid oxide electrolysis cell device is 9.03 kW, the hydrogen production power of the thermochemical reaction device is 3.46 kW, and the hydrogen production efficiency of the system is 60.86%. As can be seen from the above embodiment, the energy sources used by the system and the method thereof are solar radiation and natural gas, and the output is hydrogen and electricity. The system divides and utilizes natural sunlight, directly generates electricity by photovoltaic power generation with high-grade sunlight, and complements natural gas with low-grade sunlight to improve the energy grade. Different energy conversion methods are used to realize the orderly conversion and utilization of the temperature gradient of the divided sunlight, and based on the energy quality matching principle, different quality electrical / thermal energy is supplied to the solid oxide electrolysis cell and the thermochemical cycle to produce hydrogen. On the basis of energy cascade conversion, different qualities are complementarily coupled to provide a high-efficiency solar cascade hydrogen production approach.

[0050] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A solar radiation energy grading and residual light energy thermal complementary coupled electro / thermal chemical step hydrogen production system, characterized in that, The application relates to a solar energy conversion system, which comprises a light collecting assembly, a frequency separating assembly (2), a photovoltaic power generation device, a methane oxygen-enriched combustion high-temperature photovoltaic power generation device, a solid oxide electrolysis cell device and a thermochemical reaction device. The light collecting assembly collects sunlight, and the frequency separating assembly (2) separates the collected light beams, wherein the frequency bands suitable for photovoltaic power generation are reflected to the photovoltaic power generation device for photovoltaic power generation, and the rest of the frequency bands are twice collected by the light collecting assembly and then input to the methane oxygen-enriched combustion high-temperature photovoltaic power generation device. The methane oxygen-enriched combustion high-temperature photovoltaic power generation device uses a tubular receiver (6) to convert the twice-collected sunlight into heat energy to preheat oxygen-enriched air, and the preheated oxygen-enriched air is input into a combustion chamber (7) to be combusted with natural gas to generate first-stage high-temperature flue gas; the methane oxygen-enriched combustion high-temperature photovoltaic power generation device uses the radiant energy of the first-stage high-temperature flue gas to generate photovoltaic power, and second-stage high-temperature flue gas is discharged from the combustion chamber (7) to the solid oxide electrolysis cell device. The solid oxide electrolysis cell device uses a three-stage heat exchanger (14) and a solid oxide electrolysis cell (15) to gradually utilize the heat of the high-temperature flue gas, wherein the solid oxide electrolysis cell (15) uses the electric energy generated by the system and the heat contained in the high-temperature flue gas to perform high-temperature electrolysis to produce hydrogen, and fourth-stage high-temperature flue gas is discharged to supply the thermochemical reaction device. The thermochemical reaction device comprises a pyrolysis reaction bin (16), a hydrolysis reaction bin (17), a drying reaction bin (18) and an electrolysis reaction bin (19), and the pyrolysis reaction bin (16), the hydrolysis reaction bin (17) and the drying reaction bin (18) gradually utilize the heat energy contained in the high-temperature flue gas to drive reactions; the entire thermochemical reaction device utilizes the heat energy contained in the high-temperature flue gas and the electric energy generated by the system to realize copper-chlorine circulation and produce hydrogen.

2. The solar radiant energy grading and residual light energy thermally complementary coupled electro / thermal chemical step-hydrogen generation system of claim 1, wherein: The light collecting assembly comprises a primary light collecting assembly (1) and a secondary light collecting assembly (3); the primary light collecting assembly (1) is used for collecting natural sunlight to the frequency separating assembly (2); the frequency separating assembly (2) reflects a first light beam which can be efficiently utilized by a photovoltaic cell, and transmits the rest of the sunlight to the secondary light collecting assembly (3); and the secondary light collecting assembly (3) is used for collecting the rest of the sunlight after frequency separation to the tubular receiver (6).

3. The solar radiant energy fractionalization and residual radiant energy thermally complementary coupled electro / thermal chemical step-hydrogen generation system of claim 1 wherein: The photovoltaic power generation device comprises a first-stage photovoltaic cell (4) and a first-stage photovoltaic cell waste heat utilization device (5); the first-stage photovoltaic cell (4) is used for receiving the frequency bands reflected by the frequency separating assembly (2) to generate photovoltaic power and provide electric energy for subsequent electrolysis to produce hydrogen; the first-stage photovoltaic cell waste heat utilization device (5) recovers the heat energy of the first-stage photovoltaic cell (4) to preheat water as raw material for thermochemical reaction, and avoids temperature rise of the first-stage photovoltaic cell; and the first-stage photovoltaic cell waste heat utilization device (5) is provided with an inlet for inputting cold water and an outlet for discharging hot water.

4. The solar radiant energy fractionalization and residual radiant energy thermally complementary coupled electro / thermal chemical step-hydrogen generation system of claim 1 wherein: The methane oxygen-enriched combustion high-temperature photovoltaic power generation device comprises a tubular receiver (6), a combustion chamber (7), an emitter (8), a filter (9), a secondary photovoltaic cell (10) and a secondary photovoltaic cell waste heat utilization device (11); the tubular receiver (6) is internally fixed with a light-heat absorber, which is used for absorbing focused sunlight to convert into heat energy, preheating oxygen-enriched air, and inputting natural gas and the preheated oxygen-enriched air into the combustion chamber (7) to combust; the first-stage high-temperature flue gas generated by the natural gas oxygen-enriched combustion in the combustion chamber (7) generates radiation energy through the emitter (8), the radiation energy selectively passes through the filter (9) and is absorbed by the secondary photovoltaic cell (10) to generate electric energy; the secondary photovoltaic cell waste heat utilization device (11) recovers the heat energy of the secondary photovoltaic cell (10) to preheat water as raw material for the solid oxide water electrolysis hydrogen production reaction, and avoids the temperature rise of the secondary photovoltaic cell.

5. The solar radiant energy fractionalization and residual radiant energy thermally complementary coupled electro / thermal chemical step-hydrogen generation system of claim 1 wherein: The solid oxide electrolytic cell device comprises a first-stage heat exchanger (12), a second-stage heat exchanger (13), a third-stage heat exchanger (14) and a solid oxide electrolytic cell (15); the first-stage heat exchanger (12) recovers the heat of the high-temperature hydrogen gas and water vapor discharged from the cathode of the solid oxide electrolytic cell (15) to further heat the hot water discharged from the secondary photovoltaic cell waste heat utilization device (11); the second-stage heat exchanger (13) recovers the heat of the high-temperature oxygen gas discharged from the anode of the solid oxide electrolytic cell (15) to further heat the hot water vapor discharged from the first-stage heat exchanger (12); the third-stage heat exchanger (14) utilizes the heat contained in the second-stage high-temperature flue gas to further heat the hot water vapor discharged from the second-stage heat exchanger (13), and the heated high-temperature water vapor is input into the cathode of the solid oxide electrolytic cell (15) as electrolysis reaction raw material, the third-stage heat exchanger (14) supplies the third-stage high-temperature flue gas after heat exchange to the solid oxide electrolytic cell (15); the solid oxide electrolytic cell (15) utilizes the electric energy generated by the photovoltaic cell and the heat contained in the third-stage high-temperature flue gas to perform high-temperature electrolysis to produce hydrogen, the required electric energy is provided by the photovoltaic power generation of the system, high-temperature hydrogen gas and high-temperature water vapor not subjected to electrolysis are generated at the cathode, and high-temperature oxygen gas is generated at the anode, and the fourth-stage high-temperature flue gas after heat exchange is supplied to the thermochemical reaction device.

6. The solar radiant energy fractionalization and residual radiant energy thermal complementary coupled electro / thermal chemical hydrogen cascade production system of claim 1 wherein: The solid oxide electrolytic cell device is internally provided with a hot water / water vapor pipeline, the hot water / water vapor pipeline is sequentially connected with the first-stage heat exchanger (12), the second-stage heat exchanger (13), the third-stage heat exchanger (14) and the solid oxide electrolytic cell (15); the hot side inlet of the first-stage heat exchanger (12) is connected with the cathode outlet of the solid oxide electrolytic cell (15), and the cold side inlet is connected with the hot water outlet of the secondary photovoltaic cell waste heat utilization device (11); The hot side inlet of the secondary heat exchanger (13) is connected with the anode outlet of the solid oxide electrolysis cell (15), and the cold side inlet is connected with the cold side outlet of the primary heat exchanger (12); the cold side inlet of the tertiary heat exchanger (14) is connected with the cold side outlet of the secondary heat exchanger (13); the cathode of the solid oxide electrolysis cell (15) is provided with an inlet for high-temperature water vapor, an inlet for hydrogen, and an outlet for high-temperature hydrogen and water vapor, and the anode is provided with an outlet for high-temperature oxygen; The solid oxide electrolysis cell device is also provided with a hydrogen separator (22) for separating hydrogen and water in the mixed gas at the outlet of the primary heat exchanger (12), the separated water is used for cooling in the photovoltaic power generation device, and part of the separated hydrogen is supplied to the cathode of the solid oxide electrolysis cell (15), which effectively prevents the oxidation of the cathode material under high temperature and high humidity conditions.

7. The solar radiation energy grading and residual light energy thermal complementary coupling hydrogen production system according to claim 1, wherein: The pyrolysis reaction bin (16) uses the heat contained in the third high-temperature flue gas to drive the pyrolysis reaction, and after heat exchange, the third high-temperature flue gas is converted into fourth high-temperature flue gas with a temperature of 400-460 DEG C to supply the hydrolysis reaction bin (17); the chemical reaction equation of the pyrolysis reaction is Cu2OCl2(s)→2CuCl(l)+0.5O2(g); The hydrolysis reaction bin (17) uses the heat contained in the fourth high-temperature flue gas to drive the hydrolysis reaction, and after heat exchange, the fourth high-temperature flue gas is converted into fifth high-temperature flue gas with a temperature of 130-200 DEG C to supply the drying reaction bin (18); the chemical reaction equation of the hydrolysis reaction is 2CuCl2(s)+H2O(g)→2HCl(g)+Cu2OCl2(s), and the product HCl gas is used as raw material for the electrolysis reaction to supply the electrolysis reaction bin (19); The drying reaction bin (18) uses the heat contained in the fifth high-temperature flue gas to drive the drying reaction, and the water in the CuCl2 solution is evaporated to form solid CuCl2, and after heat exchange, the fifth high-temperature flue gas is converted into low-temperature flue gas and discharged; The electrolysis reaction bin (19) uses part of the electricity generated by the high-temperature photovoltaic power generation device by methane oxygen-enriched combustion to drive the electrolysis 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 the net reaction is water decomposition into hydrogen and oxygen.

8. The solar radiant energy fractionalization and residual radiant energy thermally complementary coupled electro / thermal chemical step-hydrogen generation system of claim 1 wherein, The system also includes a solid-liquid material transport system, which transports the solid Cu2OCl2 and HCl gas generated in the hydrolysis reaction bin (17) into the pyrolysis reaction bin (16) and the electrolysis reaction bin (19), respectively, transports the liquid CuCl generated in the pyrolysis reaction bin (16) into the electrolysis reaction bin (19), transports the CuCl2 solution generated in the electrolysis reaction bin (19) into the drying reaction bin (18), and transports the CuCl2 solid generated in the drying reaction bin (18) into the hydrolysis reaction bin (17).

9. The electro / thermochemical cascade hydrogen production system with solar radiation energy grading and residual energy thermal complementarity coupling as described in claim 1, characterized in that: The system further comprises a hydrogen storage tank (20), an oxygen storage tank (21) and a battery (23), wherein the hydrogen storage tank (20) is used to store hydrogen produced by the solid oxide electrolysis cell device and the thermo-chemical reaction device, the oxygen storage tank (21) is used to store oxygen produced by the solid oxide electrolysis cell device and the thermo-chemical reaction device, and the battery (23) is used to store the electric energy generated by the photovoltaic power generation device and the photovoltaic cell of the methane oxygen-enriched combustion high-temperature photovoltaic power generation device, and to provide power for the electrolysis process of the solid oxide electrolysis cell device and the thermo-chemical reaction device.

10. A method of electro / thermo-chemical stepwise hydrogen production based on the system of any one of claims 1-9, characterized in that, The natural sunlight is frequency-division utilized, the high-grade sunlight is directly used for photovoltaic power generation, the low-grade sunlight is complementarily used with natural gas to improve the energy grade, different energy conversion modes are used to realize the ordered conversion and utilization of the temperature gradient of the residual light after the frequency-division of the sunlight, and the complementary coupling of different qualities is realized based on the energy quality matching principle; specifically comprising the following steps: The natural sunlight is once concentrated to the frequency-division component (2), the reflected light beam is efficiently utilized by the photovoltaic power generation device, and the residual sunlight is transmitted; The oxygen-enriched air is preheated by the concentrated sunlight in the tubular receiver (6) and is burned with the natural gas in the combustion chamber (7) to generate the first-stage high-temperature flue gas with a temperature of 2000-2500 DEG C; the first-stage high-temperature flue gas with a temperature of 2000-2500 DEG C is used to generate the second-stage high-temperature flue gas with a temperature of 850-1000 DEG C by the methane oxygen-enriched combustion high-temperature photovoltaic power generation device through the thermal photovoltaic power generation of the radiation energy contained in the first-stage high-temperature flue gas; The solid oxide electrolysis cell device uses the heat energy contained in the second-stage high-temperature flue gas with a temperature of 850-1000 DEG C to heat the electrolysis reaction raw material through the three-stage heat exchanger (14), and converts the second-stage high-temperature flue gas into the third-stage high-temperature flue gas with a temperature of 750-850 DEG C which is introduced into the solid oxide electrolysis cell (15); the solid oxide electrolysis cell (15) uses the third-stage high-temperature flue gas with a temperature of 750-850 DEG C and the electric energy generated by the photovoltaic power generation to drive the hydrogen production by the solid oxide electrolysis, and converts the third-stage high-temperature flue gas into the fourth-stage high-temperature flue gas with a temperature of 530-680 DEG C which is introduced into the thermo-chemical reaction device; In the thermo-chemical reaction device, the pyrolysis reaction bin (16) uses the heat energy contained in the fourth-stage high-temperature flue gas to drive the pyrolysis reaction, and converts the fourth-stage high-temperature flue gas into the fifth-stage high-temperature flue gas with a temperature of 400-460 DEG C which is introduced into the hydrolysis reaction bin (17); the hydrolysis reaction bin (17) uses the heat energy contained in the fifth-stage high-temperature flue gas to drive the hydrolysis reaction, and converts the fifth-stage high-temperature flue gas into the sixth-stage high-temperature flue gas with a temperature of 130-200 DEG C which is introduced into the drying reaction bin (18); the drying reaction bin (18) uses the heat energy contained in the sixth-stage high-temperature flue gas to drive the drying reaction, and converts the sixth-stage high-temperature flue gas into low-temperature flue gas which is discharged; the electrolysis reaction bin (19) uses the electric energy generated by the photovoltaic power generation to perform the electrolysis reaction to produce hydrogen.

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