System and method for hydrogen production by solar thermochemical looping of manganese oxides with sodium carbonate

Abstract

The application provides a solar thermochemical cycle hydrogen production system and method of manganese oxide and sodium carbonate, wherein the device comprises: a solar pyrolysis reactor for heating to a first temperature to make manganese trioxide release oxygen to produce manganese sesquioxide and oxygen; a solar fuel reactor for heating to a second temperature to make the produced manganese sesquioxide react with sodium carbonate to produce sodium manganite, carbon dioxide and carbon monoxide; a circulating material regeneration reactor for heating to a third temperature to make the produced sodium manganite react with carbon dioxide to produce manganese trioxide and sodium carbonate, so as to realize material circulation; a water vapor shift reactor for heating to a fourth temperature to make the produced carbon monoxide react with water vapor to produce carbon dioxide and hydrogen; and a concentrated solar heat collecting device for providing reaction energy for the solar pyrolysis reactor and the solar fuel reactor.

Description

Technical Field

[0001] This disclosure relates to the field of solar thermochemical hydrogen production technology, and in particular to a solar thermochemical cycle hydrogen production system and method using manganese oxide and sodium carbonate. Background Technology

[0002] Hydrogen production through water pyrolysis by concentrating solar energy for high-temperature heat energy, and converting solar energy into stable, high-density hydrogen fuel chemical energy through thermochemical reactions, can effectively solve the problems of intermittent and unstable solar energy supply, and is an important technology for achieving efficient and stable utilization of solar energy. However, the development and application of thermochemical water splitting for hydrogen production are limited by problems such as ultra-high reaction temperature (>3000℃) and poor safety and difficulty in separating the mixed hydrogen and oxygen products.

[0003] Currently, indirect water splitting for hydrogen production through the appropriate configuration of two or more thermochemical reactions can effectively reduce the extremely high hydrogen production temperature of direct thermochemical water splitting and generate hydrogen and oxygen products at different reaction stages. Typical solar thermochemical cycle hydrogen production methods include two-step and three-step cycles.

[0004] The two-step solar thermochemical cycle method includes: firstly, pyrolyzing high-valence metal oxide MO at a high temperature of >1500℃. n Generating low-valence metal oxides MO n-δ The process involves reacting with oxygen (O2), followed by cooling a low-valence metal oxide to 700℃–1000℃, where it undergoes an oxidation reaction with water to produce hydrogen. This process also yields a new high-valence metal oxide, achieving material recycling. While this method lowers the direct pyrolysis temperature of water, the still relatively high reaction temperature (>1500℃) leads to problems such as sintering of the circulating working fluid, poor recyclability, and poor high-temperature stability of the reactor materials. Furthermore, concentrating solar energy at 1500℃ requires a large-area concentrator or a high-concentration-ratio device, resulting in poor technical and economic efficiency, high heat loss, and low energy conversion efficiency.

[0005] The solar thermochemical sulfur-iodine three-step cycle method includes: First, sulfuric acid is heated to 1000℃~1100℃ under the action of concentrated solar energy, decomposing to produce sulfur dioxide (SO2), water (H2O) and oxygen (O2); then, sulfur dioxide (SO2) reacts with water (H2O) and iodine (I2) at 20℃~120℃ to produce hydroiodic acid (HI) and sulfuric acid (H2SO4); the regenerated sulfuric acid (H2SO4) is recycled back to the sulfuric acid decomposition reaction, and the produced hydroiodic acid (HI) decomposes to produce hydrogen at 300~500℃. Although this method further reduces the hydrogen production temperature of the two-step solar thermochemical cycle, there are still corresponding problems: (1) The cycle uses sulfuric acid (H2SO4) and hydroiodic acid (HI) as circulating substances. Under high temperature conditions, they are extremely corrosive, which puts forward stringent requirements on the corrosion resistance of the reactor material. In addition, the safety is poor, the system operation stability is poor, and the lifespan is short; (2) The homogeneous liquid product hydroiodic acid (HI) generated by the Bunsen reaction is mixed with sulfuric acid (H2SO4) and is not easy to separate. It is difficult to obtain high-purity hydroiodic acid (HI) for subsequent decomposition to produce hydrogen (H2).

[0006] The existence of the above-mentioned problems limits the further development and application of solar thermochemical cycle water splitting to produce hydrogen, and requires improvement and refinement. Summary of the Invention

[0007] In view of the above problems, the present invention provides a solar thermochemical cycle hydrogen production system and method using manganese oxide and sodium carbonate to solve the shortcomings of the prior art.

[0008] This disclosure provides a solar thermochemical cycle hydrogen production system using manganese oxide and sodium carbonate, comprising: a solar pyrolysis reactor for heating to a first temperature to cause manganese trioxide to undergo an oxygen release reaction, producing manganese tetroxide and oxygen; a solar fuel reactor connected upstream to the solar pyrolysis reactor for reacting the manganese tetroxide produced by the solar pyrolysis reactor with sodium carbonate at a second temperature to produce sodium manganite, carbon dioxide, and carbon monoxide; a regenerating reactor for recycling materials, connected upstream to the solar fuel reactor for reacting the sodium manganite produced by the solar fuel reactor with carbon dioxide at a third temperature to produce manganese trioxide and sodium carbonate, thereby achieving material recycling; a water-gas shift reactor connected upstream to the regenerating reactor for reacting the carbon monoxide from the outlet of the regenerating reactor with water vapor at a fourth temperature to produce carbon dioxide and hydrogen; and a concentrating solar collector connected to the solar pyrolysis reactor and the solar fuel reactor for providing reaction energy to the solar pyrolysis reactor and the solar fuel reactor.

[0009] According to embodiments of this disclosure, the system further includes: a first cooler, connected upstream to the solar pyrolysis reactor, for cooling the oxygen produced by the solar pyrolysis reactor.

[0010] According to embodiments of this disclosure, the system further includes: a second cooler, connected upstream to the circulating material regeneration reactor, for cooling the mixture of manganese trioxide and sodium carbonate produced by the circulating material regeneration reactor; and a separation and drying unit, connected upstream to the second cooler and downstream to the solar pyrolysis reactor and the solar fuel reactor, for separating and drying the manganese trioxide and the sodium carbonate, returning the manganese trioxide to the solar pyrolysis reactor, and returning the sodium carbonate to the solar fuel reactor.

[0011] According to embodiments of this disclosure, the system further includes: a third cooler, connected upstream to the water-vapor shift reactor, for cooling the carbon dioxide and hydrogen produced by the water-vapor shift reactor; and a pressure swing adsorption unit, connected upstream to the third cooler, for separating the carbon dioxide and hydrogen.

[0012] According to an embodiment of this disclosure, the system further includes: a mixer, connected upstream to the solar fuel reactor and the pressure swing adsorption unit, and downstream to the recycle material regeneration reactor, for mixing carbon dioxide and carbon monoxide produced by the solar fuel reactor with carbon dioxide separated by the pressure swing adsorption unit, and outputting the mixture to the recycle material regeneration reactor.

[0013] According to an embodiment of this disclosure, the system further includes: a steam generator connected downstream to the water-steam shift reactor, used to heat room temperature liquid water to generate water vapor, and output the water vapor to the water-steam shift reactor.

[0014] According to an embodiment of this disclosure, the concentrating solar thermal collector of the system includes: a first solar thermal collector module connected to the solar pyrolysis reactor for supplying energy to the solar pyrolysis reactor; and a second solar thermal collector module connected to the solar fuel reactor for supplying energy to the solar fuel reactor.

[0015] Another aspect of this disclosure provides a solar thermochemical cycle method for hydrogen production using manganese oxide and sodium carbonate, applied to a system as described in any of the preceding aspects, comprising: at a first temperature, causing manganese trioxide to undergo an oxygen release reaction to produce manganese tetroxide and oxygen; at a second temperature, reacting the manganese tetroxide with sodium carbonate to produce sodium manganite, carbon dioxide, and carbon monoxide; at a third temperature, reacting the sodium manganite with carbon dioxide to produce manganese trioxide and sodium carbonate, thereby achieving a material cycle; and at a fourth temperature, reacting preheated carbon monoxide with water vapor to produce carbon dioxide and hydrogen; all of the above temperature conditions are provided by solar energy.

[0016] According to embodiments of this disclosure, the first temperature is 800–900°C, the second temperature is 600–700°C, the third temperature is 300–400°C, and the fourth temperature is 100–200°C.

[0017] According to embodiments of this disclosure, the ratio of manganese trioxide, sodium carbonate, and water vapor is 3:3:1.

[0018] The above-described at least one technical solution adopted in the embodiments of this disclosure can achieve the following beneficial effects:

[0019] This invention provides a solar thermochemical cycle hydrogen production system and method using manganese oxide and sodium carbonate. The system lowers the temperature for the two-step solar thermochemical cycle of H2O decomposition to H2 production to below 1000℃. This temperature reduction effectively extends the lifespan of the circulating materials and improves the high-temperature operational stability of the reactor materials. Furthermore, the lower reaction temperature allows for a reduction in the concentrator field area or concentration ratio, effectively saving costs, reducing heat loss, and improving technical economy and energy efficiency.

[0020] The system and method provided by this invention utilize neutral Mn2O3 and weakly alkaline Na2CO3 to cyclically decompose H2O to produce H2, effectively avoiding the poor safety and short lifespan problems caused by high-temperature acid corrosion in traditional solar thermochemical sulfur-iodine cycles. Furthermore, the intermediate products generated by the system and method provided by this invention are mostly heterogeneous, and the few homogeneous products can be separated using relatively simple and mature separation techniques (such as solution separation and pressure swing adsorption), enabling continuous and stable operation of the system. Attached Figure Description

[0021] To gain a more complete understanding of this disclosure and its advantages, reference will now be made to the following description taken in conjunction with the accompanying drawings, wherein:

[0022] Figure 1 This is a process flow diagram of the solar thermochemical cycle hydrogen production system and method using manganese oxide and sodium carbonate, according to an embodiment of the present invention.

[0023] Figure 2 This is a sub-process flow diagram of the separation and drying unit in the embodiment. Detailed Implementation

[0024] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0025] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0026] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0027] The solar thermochemical cycle hydrogen production system and method for manganese oxide and sodium carbonate provided in this embodiment involves a thermochemical cycle of neutral manganese oxide and weakly alkaline sodium carbonate, which can achieve thermochemical water decomposition to produce hydrogen at a temperature below 1000℃, while avoiding high-temperature acid corrosion and effectively solving the problem of difficulty in separating different reaction products.

[0028] The present invention provides a solar thermochemical cycle method for producing hydrogen from manganese oxide and sodium carbonate, comprising S1 to S4.

[0029] S1, at the first temperature, causes manganese trioxide to undergo an oxygen release reaction, producing manganese tetroxide and oxygen.

[0030] The first temperature is 800–900℃, and the chemical equation for this oxygen release reaction is:

[0031] 3Mn₂O₃→2Mn₃O₄+0.5O₂

[0032] S2, at the second temperature, manganese tetroxide reacts with sodium carbonate to produce sodium manganite, carbon dioxide, and carbon monoxide.

[0033] The second temperature is 600–700℃, and the chemical reaction equation for this reaction is:

[0034] 2Mn3O4+3Na2CO3→6NaMnO2+2CO2+CO

[0035] S3, at the third temperature, sodium manganeseite reacts with carbon dioxide to produce manganese trioxide and sodium carbonate, thus achieving a material cycle.

[0036] The third temperature is 300–400℃, and the chemical equation for this regeneration reaction is:

[0037] 6NaMnO2 + 3CO2 → 3Mn2O3 + 3Na2CO3

[0038] S4, at the fourth temperature, preheated carbon monoxide reacts with water vapor to produce carbon dioxide and hydrogen.

[0039] The fourth temperature is 100–200℃, and the chemical reaction equation for this water-vapor shift reaction is:

[0040] CO + H₂O → CO₂ + H₂

[0041] The overall reaction equation for the above reaction is:

[0042] H2O→H2+0.5O2

[0043] The temperature conditions described above are all provided by solar energy.

[0044] The reaction raw materials in the above method are manganese trioxide, sodium carbonate, and water vapor, in a reaction ratio of 3:3:1. The oxygen release reaction and CO production reaction are both endothermic processes, while the regeneration of recycled materials and the water-vapor shift reaction are exothermic processes, and the reaction temperature in each step is less than 1000℃. Summing up the reactions in each step yields a final reaction: water splitting to produce hydrogen.

[0045] Based on the above method, another aspect of the present invention provides a solar thermochemical cycle hydrogen production system of manganese oxide and sodium carbonate, including a concentrating solar collector, a solar pyrolysis reactor 102, coolers (103, 107 and 112), a solar fuel reactor 105, a regeneration reactor 106, a separation and drying unit 108, a mixer 109, a steam generator 110, a water-steam shift reactor 111, and a pressure swing adsorption unit 113, etc.

[0046] The solar pyrolysis reactor 102 is a cavity-type or tubular solar reactor used to receive solar thermal energy from the first solar collector module 101, heat it to a first temperature, and cause manganese trioxide (Mn2O3) to undergo an oxygen release reaction to produce manganese tetroxide (Mn3O4) and oxygen (O2).

[0047] The solar fuel reactor 105 is connected upstream to the solar pyrolysis reactor 102, which is used to react manganese tetroxide produced by the solar pyrolysis reactor 102 with sodium carbonate at a second temperature to produce sodium manganite, carbon dioxide and carbon monoxide.

[0048] The concentrating solar thermal collector includes a first solar thermal collector module 101 and a second solar thermal collector module 104. The first solar thermal collector module 101 is connected to a solar pyrolysis reactor 102 and is used to supply energy to the solar pyrolysis reactor 102. The second solar thermal collector module 104 is connected to a solar fuel reactor 105 and is used to supply energy to the solar fuel reactor 105. Optionally, the first solar thermal collector module 101 and the second solar thermal collector module 104 are tower-type or dish-type concentrating solar thermal collectors, mainly planar concentrating mirror arrays or parabolic concentrating solar reflectors. The second solar thermal collector module 104 compensates for the insufficient sensible heat carried by Mn3O4 at the outlet of the solar pyrolysis reactor 102, which prevents the room-temperature sodium carbonate (Na2CO3) from being heated to the carbon monoxide reaction temperature, and provides sufficient heat for the carbon monoxide reaction.

[0049] The recycling reactor 106 is a cavity or tubular reactor, with the solar fuel reactor 105 and mixer 109 connected upstream. It is used to react sodium manganeseite with carbon dioxide at a third temperature to produce manganese trioxide and sodium carbonate, thereby achieving material recycling.

[0050] The water-steam shift reactor 111 is a tubular reactor connected upstream to the circulating material regeneration reactor 106. It is used to react carbon monoxide and water vapor at the outlet of the circulating material regeneration reactor at a fourth temperature to produce carbon dioxide and hydrogen.

[0051] The concentrating solar thermal collector is connected to the solar pyrolysis reactor 102 and the solar fuel reactor 105, and is used to provide reaction energy for the solar pyrolysis reactor 102 and the solar fuel reactor 105.

[0052] The first cooler 103 is connected upstream to the solar pyrolysis reactor 102 and is used to cool the oxygen produced by the solar pyrolysis reactor 102. The first cooler 103 is either water-cooled or air-cooled.

[0053] The second cooler 107 is water-cooled or air-cooled, and its upstream is connected to the circulating material regeneration reactor 106 to cool the mixture of manganese trioxide and sodium carbonate produced by the circulating material regeneration reactor 106.

[0054] The separation and drying unit 108 is connected upstream to the second cooler 107 and downstream to the solar pyrolysis reactor 102 and the solar fuel reactor 105. It is used to separate and dry manganese trioxide and sodium carbonate, returning manganese trioxide to the solar pyrolysis reactor 102 and sodium carbonate to the solar fuel reactor 105. The separation and drying unit 108 includes a separation and drying subunit. The separation subunit utilizes the property that sodium carbonate (Na₂CO₃) is soluble in water while manganese trioxide (Mn₂O₃) is not, employing a solution separation method. A mixture of the two is simultaneously added to water, and manganese trioxide (Mn₂O₃) is obtained as pure substance through precipitation and drying. The sodium carbonate (Na₂CO₃) solution is evaporated, crystallized, and dried to obtain pure sodium carbonate (Na₂CO₃).

[0055] The third cooler 112 is connected upstream to the water-gas shift reactor 111 and is used to cool the carbon dioxide and hydrogen produced by the water-gas shift reactor 111.

[0056] The pressure swing adsorption unit 113 is connected upstream to a third cooler 112 for separating carbon dioxide and hydrogen.

[0057] The mixer 109 is connected upstream to the solar fuel reactor 105 and the pressure swing adsorption unit 113, and downstream to the recycle material regeneration reactor 106. It is used to mix and exchange heat between the carbon dioxide and carbon monoxide produced by the solar fuel reactor 105 and the carbon dioxide separated by the pressure swing adsorption unit 113, and output the mixture to the recycle material regeneration reactor 106.

[0058] The steam generator 110 is a saturated steam generator or a superheated steam generator, and is connected downstream to the water-steam shift reactor 111. It is used to heat room temperature liquid water to generate steam and output the steam to the water-steam shift reactor 111.

[0059] The process flow of the solar thermochemical cycle hydrogen production system and method using manganese oxide and sodium carbonate provided by the present invention will be described in detail below through a specific embodiment.

[0060] Example 1

[0061] Figure 1 This is a process flow diagram of the solar thermochemical cycle hydrogen production system and method using manganese oxide and sodium carbonate of the present invention.

[0062] 3 mol of Mn2O3 at room temperature enters the solar pyrolysis reactor 102. Using the solar thermal energy collected by the first solar collector module 101, the Mn2O3 at room temperature is heated to the oxygen release reaction temperature (800-900℃), and an oxygen release reaction occurs to generate 2 mol of Mn3O4 and 0.5 mol of O2.

[0063] The 0.5 mol O2 produced by the oxygen release reaction at 800–900°C is cooled to room temperature by the first cooler 103.

[0064] The 2 mol Mn3O4 produced by the oxygen release reaction enters the solar fuel reactor 105. Under the action of concentrated solar energy collected by the second solar collector module 104, it reacts with 3 mol Na2CO3 at room temperature to produce carbon monoxide, generating 6 mol NaMnO2 and a mixed gas of 1 mol CO and 2 mol CO2.

[0065] The 1 mol CO and 2 mol CO2 mixture from the outlet of the solar fuel reactor 105 is fully mixed and heat exchanged with the 1 mol CO2 at about 40°C from the pressure swing adsorption unit in the mixer 109, and a 1 mol CO and 3 mol CO2 mixture at 300-400°C is obtained at the outlet of the mixer 109.

[0066] The 6 mol NaMnO2 from the outlet of the solar fuel reactor 105 and the 1 mol CO and 3 mol CO2 mixture from the outlet of the mixer 109 enter the regeneration reactor 106 for a regeneration reaction of the recycled materials. Since this reaction occurs only between NaMnO2 and CO2, the gas obtained at the outlet of the regeneration reactor 109 is CO.

[0067] The solid-phase mixed reaction product of 3 mol Mn2O3 and 3 mol Na2CO3 generated in the regeneration reactor 106 at 300-400℃ is cooled to room temperature by the second cooler 107 and enters the downstream separation and drying unit 108.

[0068] The separation and drying unit 108 includes a separator 108a, an evaporator 108b, a dryer 108c, and a dryer 108d, such as Figure 2 As shown, the separation of Na₂CO₃ and Mn₂O₃ is achieved by solution separation, taking advantage of the fact that Na₂CO₃ is readily soluble in water while Mn₂O₃ is insoluble in water. First, a mixture of Mn₂O₃ and Na₂CO₃ cooled to room temperature is introduced into a water-containing separator 108a. The Na₂CO₃ in the mixture dissolves in water to obtain a saturated Na₂CO₃ solution. This solution is then evaporated in evaporator 108b to obtain Na₂CO₃ crystals, which are further dried in dryer 108c to obtain pure Na₂CO₃. The precipitate in separator 108a is Mn₂O₃, which is dried in dryer 108d to obtain pure Mn₂O₃.

[0069] The 3 mol Mn2O3 and 3 mol Na2CO3 obtained at room temperature after the separation and drying unit are respectively fed into the solar pyrolysis reactor 102 and the solar fuel reactor 105, where they undergo oxygen release and carbon monoxide production reactions again.

[0070] 1 mol of CO at 300-400°C obtained from the outlet of the regeneration reactor 106 enters the water-steam shift reactor 111, where it mixes and exchanges heat with saturated steam or superheated steam generated by the steam generator 110, and undergoes a water-steam shift reaction to generate 1 mol of CO2 and 1 mol of H2.

[0071] A mixture of 1 mol CO2 and 1 mol H2 gas at 150-200°C at the outlet of the water-gas shift reactor 111 is cooled to about 40°C by the third cooler 112 and then enters the pressure swing adsorption unit 113.

[0072] 1 mol of CO2 obtained through pressure swing adsorption unit 113 is mixed with 1 mol of CO and 2 mol of CO2 from solar fuel reactor 105 to obtain 1 mol of CO and 3 mol of CO2, which provides feed gas for regeneration reactor.

[0073] After the CO2 and H2 mixture at the outlet of the third cooler 112 is separated into CO2 by pressure swing adsorption, pure H2 is obtained.

[0074] According to the above embodiments, the present invention provides a solar thermochemical cycle hydrogen production system and method using manganese oxide and sodium carbonate. This system lowers the temperature for the two-step solar thermochemical cycle of H2O decomposition to H2 production to below 1000℃. The lower temperature effectively extends the lifespan of the circulating materials and improves the high-temperature operational stability of the reactor materials. Furthermore, the lower reaction temperature can reduce the area of ​​the concentrator lens or the concentration ratio, effectively saving costs, reducing heat loss, and improving technical economy and energy efficiency.

[0075] The system and method provided by this invention utilize neutral Mn2O3 and weakly alkaline Na2CO3 to cyclically decompose H2O to produce H2, effectively avoiding the poor safety and short lifespan problems caused by high-temperature acid corrosion in traditional solar thermochemical sulfur-iodine cycles. Furthermore, the intermediate products generated by the system and method provided by this invention are mostly heterogeneous, and the few homogeneous products can be separated using relatively simple and mature separation techniques (such as solution separation and pressure swing adsorption), enabling continuous and stable operation of the system.

[0076] Those skilled in the art will understand that the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0077] Although this disclosure has been shown and described with reference to specific exemplary embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made to this disclosure without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents. Therefore, the scope of this disclosure should not be limited to the above embodiments, but should be defined not only by the appended claims, but also by their equivalents.

Claims

1. A solar thermochemical cycle hydrogen production system using manganese oxide and sodium carbonate, characterized in that, include: A solar pyrolysis reactor (102) is used to heat to a first temperature to cause manganese trioxide to undergo an oxygen release reaction, producing manganese tetroxide and oxygen. A solar fuel reactor (105) is connected upstream to the solar pyrolysis reactor (102) for reacting manganese tetroxide produced by the solar pyrolysis reactor (102) with sodium carbonate under a second temperature condition to produce sodium manganite, carbon dioxide and carbon monoxide. The recycling reactor (106) is connected upstream to the solar fuel reactor (105) for reacting the sodium manganite with carbon dioxide under a third temperature condition to produce manganese trioxide and sodium carbonate, thereby realizing material recycling. A water-steam shift reactor (111) is connected upstream to the circulating material regeneration reactor (106) for reacting carbon monoxide and water vapor at the outlet of the circulating material regeneration reactor (106) under a fourth temperature condition to produce carbon dioxide and hydrogen. A concentrating solar thermal collector is connected to the solar pyrolysis reactor (102) and the solar fuel reactor (105) to provide reaction energy for the solar pyrolysis reactor (102) and the solar fuel reactor (105); The second cooler (107), connected upstream to the circulating material regeneration reactor (106), is used to cool the mixture of manganese trioxide and sodium carbonate produced by the circulating material regeneration reactor (106); The separation and drying unit (108) is connected upstream to the second cooler (107) and downstream to the solar pyrolysis reactor (102) and the solar fuel reactor (105). It is used to separate and dry the manganese trioxide and the sodium carbonate, and to return the manganese trioxide to the solar pyrolysis reactor (102) and the sodium carbonate to the solar fuel reactor (105). The third cooler (112) is connected upstream to the water-gas shift reactor (111) and is used to cool the carbon dioxide and hydrogen produced by the water-gas shift reactor (111); A pressure swing adsorption unit (113) is connected upstream to the third cooler (112) for separating the carbon dioxide and hydrogen. The mixer (109) is connected upstream to the solar fuel reactor (105) and the pressure swing adsorption unit (113), and downstream to the recycle material regeneration reactor (106). It is used to mix the carbon dioxide and carbon monoxide produced by the solar fuel reactor (105) with the carbon dioxide separated by the pressure swing adsorption unit (113) and output it to the recycle material regeneration reactor (106).

2. The system according to claim 1, characterized in that, Also includes: The first cooler (103), connected upstream to the solar pyrolysis reactor (102), is used to cool the oxygen produced by the solar pyrolysis reactor (102).

3. The system according to claim 1, characterized in that, Also includes: A steam generator (110) is connected downstream to the water-steam shift reactor (111) for heating room temperature liquid water to generate steam and outputting the steam to the water-steam shift reactor (111).

4. The system according to claim 1, characterized in that, The concentrated solar thermal collector includes: The first solar thermal collector module (101) is connected to the solar pyrolysis reactor (102) and is used to supply energy to the solar pyrolysis reactor (102); The second solar thermal collector module (104) is connected to the solar fuel reactor (105) and is used to supply energy to the solar fuel reactor (105).

5. A solar thermochemical cycle method for hydrogen production using manganese oxide and sodium carbonate, applied to the system described in any one of claims 1 to 4, characterized in that, include: At the first temperature, manganese trioxide undergoes an oxygen release reaction to produce manganese trioxide and oxygen. At a second temperature, the manganese tetroxide reacts with sodium carbonate to produce sodium manganite, carbon dioxide, and carbon monoxide. At the third temperature, the sodium manganite reacts with carbon dioxide to produce manganese trioxide and sodium carbonate, thus achieving a material cycle. At the fourth temperature, carbon monoxide reacts with water vapor to produce carbon dioxide and hydrogen. The temperature conditions described above are all provided by solar energy.

6. The method according to claim 5, characterized in that, The first temperature is 800~900℃, the second temperature is 600~700℃, the third temperature is 300~400℃, and the fourth temperature is 100~200℃.

Images