A system for producing hydrocarbons by electrolysis of solid oxides driven by solar light

Abstract

The present invention relates to the field of preparing hydrocarbons by electrolysis, and aims to provide a system for preparing hydrocarbons by electrolysis of solid oxides driven by solar energy. The system includes a solar thermal collection system and a light-driven electrolysis reaction system; the solar thermal collection system is composed of a light-gathering device and a light-guiding device; the light-driven electrolysis reaction system includes an electrolysis reaction chamber and an intake and exhaust system; the solid oxide electrolysis cell is a flat plate structure or a tubular structure, including a cathode layer, an electrolyte layer and an anode layer arranged in sequence, the cathode layer is composed of a solid oxide semiconductor material with heat collection performance and a non-fully covered metal current collecting layer, and the end of the light column is aligned with the cathode layer surface of the solid oxide electrolysis cell. The present invention can utilize the photogenerated carriers of the semiconductor for photocatalysis or photoreaction during the electrolysis reaction, and the bias voltage required to overcome the reaction energy barrier is low, thereby achieving energy saving and consumption reduction; it overcomes the problems of complex reaction process and high energy barrier, and improves yield and selectivity.

Description

Technical Field

[0001] The present invention relates to the field of preparing hydrocarbons by electrolysis, and in particular to a system for preparing hydrocarbons by electrolyzing and reducing carbon dioxide and water using solid oxide driven by solar light. Background Art

[0002] Adjusting the energy structure and replacing fossil energy with clean energy such as solar energy is the main way to reduce carbon dioxide emissions. The storage, conversion and utilization of carbon dioxide, such as converting carbon dioxide and water into hydrocarbons for use in the chemical industry, is also a feasible strategy.

[0003] Researchers have proposed a solar-based solid oxide electrolysis cell technology that uses clean solar energy to produce hydrocarbons. Solid oxide electrolysis cells operating in the temperature range of 500-1000°C are considered to be an efficient electrolysis method, and the carbon dioxide conversion reaction therein has also been widely studied. Solar-based solid oxide electrolysis cells use the heat and electricity generated by solar energy to jointly participate in the production of hydrocarbons. The direct participation of photothermal energy and the use of long-wave energy in the visible-infrared band of solar energy improve the overall utilization efficiency of solar energy. However, this technology still has some problems and room for improvement.

[0004] First, in existing solid oxide electrolyzers, the conversion reaction of carbon dioxide and water is very difficult. Since carbon dioxide is an inactive molecule with stable chemical properties, its reaction with water to produce hydrocarbons requires a multi-electron transfer reaction, which has a complex reaction process and a high energy barrier, resulting in low conversion rate and selectivity in the hydrocarbon production process.

[0005] Secondly, the current technology mainly focuses on utilizing the thermal and electrical energy of solar energy, while the direct utilization of solar light energy has not been fully considered. Therefore, the existing solid oxide electrolysis cell technology generally lacks the use of direct light-driven. Light-driven reaction is a chemical reaction driven by photogenerated carriers generated by semiconductors under light. It has been proven in the fields of photocatalysis and photoelectrochemistry that it can fully or partially provide energy for the preparation of hydrocarbons. However, there is no public literature on the application of light-driven methods to solid oxide electrolysis cells.

[0006] In response to this technical problem, the present invention proposes a system for preparing hydrocarbons by electrolysis of solid oxides driven by solar light. The overall utilization rate of solar energy is further improved by introducing light drive, and the problem of difficult conversion of carbon dioxide and water is solved. Summary of the invention

[0007] The main purpose of the present invention is to overcome the problems and shortcomings in the prior art and provide a system for preparing hydrocarbons based on solar light-driven solid oxide electrolysis.

[0008] To realize the above conception, the solution of the present invention is:

[0009] A system for preparing hydrocarbons based on solar light-driven solid oxide electrolysis is provided, comprising a solar light-heat collection system and a light-driven electrolysis reaction system; wherein:

[0010] The solar thermal collection system is composed of a light concentrator and a light guide device, which is used to collect sunlight and realize conduction and irradiation; the light guide device is in the shape of a hollow tube, and a quartz light guide column is arranged along its axial direction, and a radial spacing is maintained between the light guide column and the tube wall;

[0011] The light-driven electrolytic reaction system comprises an electrolytic reaction chamber and an air intake and exhaust system; an insulating layer is arranged outside the air intake and exhaust system and the light guide device; the electrolytic reaction chamber is a hollow chamber, and a solid oxide electrolytic cell arranged inside the chamber divides the chamber into two parts, a cathode chamber and an anode chamber; the solid oxide electrolytic cell is a flat plate structure or a tubular structure, comprising a cathode layer, an electrolyte layer and an anode layer arranged in sequence, and the cathode layer is composed of a solid oxide semiconductor material with heat collection performance and a non-fully covered metal collector layer; the air intake and exhaust system comprises two groups of air intake ports and air exhaust ports, and pipelines respectively connected thereto; wherein the air intake of the cathode chamber introduces a mixed gas containing carbon dioxide and water through a pipeline, The air inlet of the anode chamber introduces carrier gas through a pipeline; the exhaust port of the cathode chamber discharges products containing hydrocarbons through a pipeline, and an air electrode is installed at the end of the pipeline; the exhaust port of the anode chamber discharges carrier gas containing oxygen through a pipeline, and an air electrode is installed at the end of the pipeline; the external power supply is connected to the two air electrodes respectively, and the air electrodes are connected to the anode layer and the current collecting layer in the cathode layer of the solid oxide electrolytic cell through wires arranged in the pipeline; the end of the light guide column is aligned with the surface of the cathode layer of the solid oxide electrolytic cell, the solid oxide semiconductor material absorbs thermal energy in sunlight, and at the same time uses the photogenerated carriers of the semiconductor for light driving and photocatalysis, so as to realize the synergistic electrolysis reaction of light, heat and electricity.

[0012] As a preferred solution of the present invention, in the light guiding device, a vacuum is maintained in the annular tube-shaped cavity between the light guiding column and the tube wall.

[0013] As a preferred embodiment of the present invention, a gas flow meter and a bubbler are provided on the pipeline for introducing a mixed gas of carbon dioxide and water, and the bubbler is connected to a carbon dioxide gas source and a water source, respectively; a gas flow meter is provided on the pipeline for introducing a carrier gas, and the gas flow meter is connected to a carrier gas bottle; a product collection tank is provided on the pipeline for discharging the product.

[0014] As a preferred solution of the present invention, the focusing device is a tower concentrator, a trough concentrator, a Fresnel concentrator or a dish concentrator.

[0015] As a preferred embodiment of the present invention, the external power source is a photovoltaic energy storage power generation device, which is used to apply a voltage less than 1.48V to the air electrode.

[0016] As a preferred embodiment of the present invention, the cross section of the quartz light guide column has the same shape and area as that of the solid oxide electrolytic cell.

[0017] As a preferred embodiment of the present invention, the metal current collecting layer is a metal mesh made of gold, silver or platinum.

[0018] As a preferred embodiment of the present invention, the end of the light-guiding device has an extended hollow tubular structure, and a radially outward end face flange is arranged at the end of the light-guiding device; the intake and exhaust system as a whole is a hollow plunger structure, and is mounted in the tubular structure at the end of the light-guiding device, and a sealed gap is formed between the two; the length of the intake and exhaust system is smaller than the tubular structure, and the internal space formed by the two is used as an electrolysis reaction chamber; a raised support ring with a relatively slightly smaller radius is provided on the end face of the plunger structure, and the solid oxide electrolytic cell is a flat plate structure and is fixedly mounted on the support ring with its edge; the air inlet and exhaust port of the cathode chamber are arranged on the end face of the plunger structure outside the support ring, and the air inlet and exhaust port of the anode chamber are arranged on the end face of the plunger structure inside the support ring, and each air intake and exhaust pipeline is arranged in the cavity of the plunger structure parallel to the axial direction.

[0019] As a preferred solution of the present invention, an end face flange extending radially outward is provided at the outer end of the plunger structure and is fixedly connected to the end face flange of the light guide device by means of a screw or bolt assembly.

[0020] As a preferred solution of the present invention, a radially outward end face flange is provided at the other end of the light guide device, and a hollow cylindrical heat-insulating layer is arranged around the outside of the light guide device and located between the two end face flanges.

[0021] Description of the invention principle:

[0022] In the present invention, the solar thermal collection system collects sunlight to achieve direct illumination of the solid oxide semiconductor material in the electrolytic reaction chamber, and uses an insulating layer to maintain heat to stabilize the reaction temperature in the reaction pool. The light guide device (and light guide column) adopts a highly light-transmitting quartz material, and utilizes its total reflection characteristics to enable most of the sunlight to directly irradiate the surface of the solid oxide, thereby avoiding the divergence loss of light. The opposite sides of the electrolytic reaction chamber are designed as a relatively long tubular structure, which can keep the electrolytic reaction chamber at a sufficient distance from the surrounding environment to prevent heat loss. The insulating layer of aluminosilicate material surrounding the outside of the light guide device and the intake and exhaust system can prevent heat loss. The bottom end of the light guide column is facing the light-receiving surface of the solid oxide electrolytic cell, and the selective light absorption and heat collection of the solid oxide semiconductor material realizes the efficient use of sunlight, reducing reflection loss and thermal radiation loss.

[0023] In the electrolysis reaction chamber, the mixed gas of carbon dioxide and water as the reaction raw materials flows into the cathode chamber. Under the conditions of 500-1000℃, atmospheric pressure and direct sunlight, the conversion reaction is completed on the cathode layer surface of the solid oxide electrolytic cell. The product is hydrocarbons (including but not limited to methane, ethane, ethylene). The overall reaction here is expressed as: CO2+H2O→C X H Y In this process, oxygen atoms penetrate the electrolyte layer and generate oxygen in the anode layer. When the carrier gas (including but not limited to nitrogen and air) flows through the anode chamber, it takes away the oxygen generated by the reaction and maintains a low oxygen partial pressure at the anode. An external power supply applies a voltage of less than 1.48V to the air electrode, and uses the wires in the pipeline to connect the cathode layer and the anode layer respectively to achieve electrical conduction to the electrolysis reaction chamber.

[0024] After the cathode layer surface of the solid oxide electrolysis cell is directly exposed to light, short-wave ultraviolet visible light participates in the light-driven reaction, and long-wave visible infrared light participates in the heat collection part to maintain the reaction temperature (500-1000℃), while the electrical energy part can come from commercial photovoltaic / photothermal technology, thus distinguishing three energy forms based on solar energy: light, heat and electricity. The carriers generated by semiconductor illumination provide energy for the hydrocarbon reaction part in a light-driven method. The solid oxide electrolysis cell operating at a low voltage of less than 1.48V is a reaction in which electrical energy and thermal energy participate together, thereby realizing a hydrocarbon synthesis reaction in which the three intermediate energy forms of light, heat and electricity based on solar energy participate together.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. Compared with the existing solid oxide electrolytic cells that can only utilize heat and electricity generated by solar energy, the present invention also utilizes the photogenerated carriers of semiconductors for photocatalysis or photoreaction during the electrolysis reaction; it can reduce the bias voltage required to overcome the reaction energy barrier and achieve energy saving and consumption reduction. In the process of applying light-driven reactions to the solid oxide cell to prepare hydrocarbons, the problems of complex reaction process and high energy barrier of carbon dioxide and water are overcome, and the yield and selectivity of hydrocarbons are improved.

[0027] 2. The present invention converts low-quality infrared light into thermal energy while utilizing high-quality ultraviolet and visible light for light-driven reactions, thereby achieving graded and quality-based utilization of the full spectrum of sunlight.

[0028] 3. The system uses photothermal collection and utilization technology to allow the solid oxide electrolytic cell to directly receive light, and solar energy is directly used for electrolysis reactions, thereby improving energy utilization efficiency.

[0029] 4. The main structure of the system adopts an integrated design, which can avoid the divergence of light and ensure that sunlight directly shines on the cathode layer on the surface of the solid oxide electrolytic cell, while meeting the requirements of photothermal collection and electrolytic cell reaction.

[0030] 5. The reaction products based on this system are controllable and can convert carbon dioxide and water into hydrocarbons. Since the types of reaction products are controllable, it has broad application prospects in the fields of environmental protection and energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the system for preparing hydrocarbons by electrolysis in the present invention.

[0032] The reference numerals in the figure are: light guide device 1; air intake and exhaust system 2; insulation layer 3; electrolysis reaction chamber 4; mixed gas containing carbon dioxide and water 5; carrier gas 6; gas flow meter 7; product collection tank 8; air electrode 9; external power supply 10. DETAILED DESCRIPTION

[0033] The serial numbers assigned to the components in this application, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings). In the description of this application, it should be understood that the orientation or position relationship indicated by the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. are based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0034] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0035] The present invention is further described in detail below with reference to the accompanying drawings and examples.

[0036] 1. System structure description

[0037] like Figure 1As shown, the present invention is a system for preparing hydrocarbons based on solar light-driven solid oxide electrolysis, including a solar thermal collection system and a light-driven electrolysis reaction system. Among them, the solar thermal collection system is composed of a focusing device (not shown in the figure) with a concentration ratio of 10-100 and a light guide device 1, which is used to collect sunlight and realize conduction and irradiation. The focusing device can be a tower concentrator, a trough concentrator, a Fresnel concentrator or a dish concentrator. The light guide device 1 is in the shape of a hollow tube, and a quartz light guide column is provided at its central axis position, and a radial spacing is maintained between the light guide column and the tube wall. In order to avoid heat loss, the annular tube-shaped cavity between the light guide column and the tube wall can be kept vacuum.

[0038] The light-driven electrolytic reaction system includes an electrolytic reaction chamber 4 and an intake and exhaust system 2 .

[0039] The electrolytic reaction chamber 4 is a hollow chamber, in which a solid oxide electrolytic cell is arranged, and the chamber is divided into two parts: a cathode chamber and an anode chamber. The solid oxide electrolytic cell can be a flat plate structure or a tubular structure, including a cathode layer, an electrolyte layer and an anode layer arranged in sequence, and the cathode layer is composed of a solid oxide semiconductor material with heat collection performance and a non-fully covered metal collector layer. The metal collector layer can be a metal mesh made of gold, silver or platinum. The intake and exhaust system 2 includes two groups of air inlets and exhaust ports, and pipelines connected thereto respectively. Among them, the air inlet of the cathode chamber introduces a mixed gas 5 of carbon dioxide and water through a pipeline, and the air inlet of the anode chamber introduces a carrier gas 6 through a pipeline; the exhaust port of the cathode chamber discharges products containing hydrocarbons through a pipeline, and an air electrode 9 is installed at the end of the pipeline; the exhaust port of the anode chamber discharges a carrier gas containing oxygen through a pipeline, and another air electrode 9 is installed at the end of the pipeline. A gas flow meter 7 and a bubbler (not shown in the figure) are provided on the pipeline for introducing the mixed gas 5 of carbon dioxide and water, and the bubbler is connected to the carbon dioxide gas source and the water source respectively; another gas flow meter 7 is provided on the pipeline for introducing the carrier gas 6, and the gas flow meter 7 is connected to the carrier gas bottle. A product collection tank 8 is provided on the pipeline for discharging the product. An external power supply 10 is respectively connected to two air electrodes 9 for applying a voltage less than 1.48V thereto, and the current collecting layers in the anode layer and the cathode layer are connected through a wire provided in the pipeline to supply power to the two poles of the solid oxide electrolytic cell. The end of the light guide column is aligned with the cathode layer surface of the solid oxide electrolytic cell for projecting the collected sunlight. The solid oxide material on the side surface absorbs the heat energy in the sunlight, and also uses the photogenerated carriers of the semiconductor for light driving and photocatalysis, so as to realize the electrolytic reaction of the three synergistic elements of light, heat and electricity. In order to avoid the waste of solar energy, the cross section of the quartz light guide column has the same shape and equal area as the solid oxide electrolytic cell. In addition, an insulation layer 3 is provided outside the intake and exhaust system 2 and the light guide device 1, and its material can be selected as an insulation material of aluminosilicate. The external power source 10 can be a photovoltaic energy storage power generation device, which can further realize the comprehensive utilization of solar energy; of course, it can also use the power supply from other new energy power generation equipment or the public power grid.

[0040] In order to further improve the utilization efficiency of sunlight, the present invention has innovatively designed the solar thermal collection system and the light-driven electrolysis reaction system, and designed the light guide device 1 and the intake and exhaust system 2 as an integrated structure. Figure 1As shown, an extended hollow tubular structure is further provided at the end of the light guide device 1, and a radially extending end face flange is provided at the very end. The overall shape of the air intake and exhaust system 2 is a hollow plunger structure, and the plunger structure is sleeved in the tubular structure extending from the end of the light guide device 1, and the two are fitted with a sealed gap. The length of the air intake and exhaust system 2 is smaller than the tubular structure, and the internal space formed by the two is used as the electrolytic reaction chamber 4. A raised support ring with a relatively slightly smaller radius (it can also be other cross-sectional shapes) is provided on the end face of the plunger structure. The solid oxide electrolytic cell in this example is a flat plate structure, and its edge is fixedly mounted on the support ring. The air inlet and exhaust port of the cathode chamber are arranged on the end face of the plunger structure outside the support ring, and the air inlet and exhaust port of the anode chamber are arranged on the end face of the plunger structure inside the support ring. Each air intake and exhaust pipeline is arranged in the cavity of the plunger structure parallel to the axial direction. In order to ensure stable installation, a radially extending end face flange is provided at the outer end of the plunger structure, and is fixedly connected to the end face flange at the lower side of the light guide device 1 by means of a screw or bolt assembly. A radially extending end face flange is also provided at the upper end of the light guide device 1, and at this time, the hollow cylindrical insulation layer 3 is arranged around the outer side of the light guide device 1 and is located between the two end face flanges.

[0041] As common knowledge, necessary sensors and control devices need to be configured to put the system of the present invention into operation. For example, a temperature sensor needs to be installed in the electrolysis reaction chamber, and the voltage provided by the external power supply 10, the intensity of sunlight collected by the focusing device, etc. need to be regulated according to the control requirements of the electrolysis reaction. The applicant believes that these control devices or control methods are technical means that are well-known to those skilled in the art, and therefore will not be described in detail in the present invention.

[0042] 2. Preparation of solid oxide electrolytic cell

[0043] In the present invention, the solid oxide electrolytic cell may be a flat plate structure or a tubular structure, including a cathode layer, an electrolyte layer and an anode layer arranged in sequence, wherein the cathode layer is composed of a solid oxide semiconductor material having heat collection performance and a non-fully covered metal current collecting layer. The specific preparation steps are exemplified as follows:

[0044] (1) Determine the solid oxide semiconductor material

[0045] Solid oxide semiconductor materials can be single components or multi-component composites, and should meet the electrode reaction requirements (A) of solid oxide batteries, as well as the solar energy utilization requirements (B) of light-driven and heat-collected. Among them, requirement (A) includes but is not limited to catalytic reaction performance, high temperature stability and tolerance to redox atmosphere; requirement (B) includes but is not limited to semiconductor properties of generating photogenerated carriers under light conditions, photocatalytic or photoreaction performance, and heat collection performance under sunlight conditions.

[0046] (2) Preparation of solid oxide semiconductor materials

[0047] Solid oxide semiconductor materials can be directly purchased from commercial products, such as SrTiO3 (12060-59-2) produced by Aladdin. Alternatively, they can be prepared by themselves with reference to public literature.

[0048] For example, prepare one or more material powders that meet the requirements, and combine the possible multiple materials in different ways. The preparation methods of material powders include but are not limited to solid phase reaction method, sol-gel method, solvent thermal method, and molten salt method. The combination method can be uniform mixing or sequential attachment to the substrate: including but not limited to impregnation method, vapor deposition method, and atomic layer deposition method.

[0049] As an example, reference may be made to the preparation technology described in the document Physics of SrTiO3-based heterostructures and nanostructures: a review (DOI: 10.1088 / 1361-6633 / aa892d) or the preparation scheme disclosed in the patent method for preparing strontium titanate spherical nanocrystals (CN109850938A).

[0050] (3) Construction of solid oxide electrolytic cell

[0051] The selected solid oxide semiconductor material is used as a cathode material, and is combined with the electrolyte and anode materials in conventional technology to construct a solid oxide electrolytic cell. This part of the content belongs to the prior art. The electrolytic cell can be a flat structure or a tubular structure, and includes at least three parts: an anode layer, an electrolyte layer, and a cathode layer. Alternatively, the selected solid oxide semiconductor material can also be combined with a conventional half-cell matrix to construct an electrolytic cell; the combination method includes but is not limited to screen printing, spin coating, and spraying.

[0052] In addition, it is necessary to add a metal current collecting layer to the cathode layer and connect the wires. The metal current collecting layer is used to partially cover the cathode layer to retain the possibility of light exposure. Specifically, a mesh current collecting layer and other solutions can be used. The current collecting layer and wire materials should have high temperature resistance and chemical stability, and materials such as gold, silver, and platinum can be used.

[0053] 3. Examples of how to use the system

[0054] 1. The system of the present invention can be used to realize the production of hydrocarbons by solar light-driven solid oxide electrolysis cells.

[0055] First, the solar light is collected by the light concentrator in the solar thermal collection system, and the sunlight is conducted by the quartz light guide column in the light guide device 1, and finally irradiated on the surface of the solid oxide electrolytic cell in the electrolytic reaction chamber. The solid oxide semiconductor material in the cathode layer continues to collect heat until the temperature of the electrolytic reaction chamber is in the range of 500-1000°C.

[0056] Then, a mixed gas containing carbon dioxide and water (which may further contain inert gases such as nitrogen and argon) is introduced into the cathode chamber through a bubbler, wherein the ratio of carbon dioxide to water can be controlled in the range of 0.5 to 1 by volume ratio. A carrier gas (including but not limited to nitrogen or air) is introduced into the anode chamber through a carrier gas bottle. The flow rates of the mixed gas in the cathode chamber and the carrier gas in the anode chamber are quantified by two gas flow meters 7, respectively, and controlled in a volume ratio of 1:1. The pressures in the anode chamber and the cathode chamber are both at normal pressure. A voltage of less than 1.48 V is applied to the air electrode 9 by an external power supply 10, and the air electrode is connected to the current collecting layers in the anode layer and the cathode layer of the solid oxide electrolytic cell through a wire arranged in the pipeline.

[0057] The solid oxide semiconductor material on the surface of the cathode layer will absorb heat from the sunlight, and after contacting with the mixture of carbon dioxide and water, the cathode layer surface will complete the conversion reaction under the conditions of 500-1000°C, atmospheric pressure, and direct sunlight. The product is hydrocarbons (including but not limited to methane, ethane, and ethylene). In this process, oxygen atoms penetrate the electrolyte layer and generate oxygen in the anode layer. When the carrier gas (including but not limited to nitrogen and air) flows through the anode chamber, it takes away the oxygen produced by the reaction and maintains a low oxygen partial pressure at the anode. The electrolytic cell operates in an endothermic state to directly utilize the thermal energy in sunlight, and the light-driven effect of the solid oxide semiconductor material is also utilized in the catalytic reaction, realizing a light-heat-electricity synergistic reaction.

[0058] Finally, the hydrocarbons produced in the cathode chamber are collected by the product collection tank 8, and the oxygen produced in the anode chamber is carried by the carrier gas and discharged from the system. 2. Specific embodiment 1

[0060] (1) According to the protocol described in Durability and Stability of LSCF Composite Cathode for Intermediate-Low Temperature of Solid Oxide Fuel Cell (IT-LT SOFC): Short Review (DOI: 10.4028 / www.scientific.net / AMR.893.732), La was prepared by the sol-gel method. 0.6 Sr 0.4 Co 0.2 Fe 0.8O3. It is used as a solid oxide semiconductor material, an electrolyte material (YSZ) and an anode material (LSM) to construct a solid oxide electrolytic cell according to conventional technology.

[0061] (2) Use a dish concentrator to collect light with a concentration ratio of 50, and then guide it through a quartz light guide column to directly illuminate the surface of the solid oxide electrolytic cell. It is calculated that about 80% of the light reaches the cathode surface, and heat collection continues until the temperature of the electrolytic reaction chamber reaches 800°C.

[0062] (3) A mixture of carbon dioxide, water and nitrogen is introduced into the cathode chamber, and the flow rates before mixing are 10 sccm, 20 sccm and 70 sccm respectively; the atmosphere of the anode chamber is nitrogen, and the flow rate is 100 sccm; an external power supply applies a constant voltage of 0.8 V to operate the electrolytic cell, and the product obtained by the reaction is methane. 3. Specific embodiment 2

[0064] (1) Referring to the scheme described in the literature of Physics of SrTiO3-based heterostructures and nanostructures: areview (DOI: 10.1088 / 1361-6633 / aa892d), 0.08Al-La was prepared by sol-gel method and molten salt method. 0.3 Sr 0.7 TiO3 is used as a solid oxide semiconductor material, an electrolyte material (YSZ) and an anode material (LSM) to construct a solid oxide electrolytic cell according to conventional technology.

[0065] (2) Use a dish concentrator to collect light with a concentration ratio of 50, and then guide it through a quartz light guide column to directly illuminate the surface of the solid oxide electrolytic cell. It is calculated that about 80% of the light reaches the cathode surface, and heat collection continues until the temperature of the electrolytic reaction chamber reaches 800°C.

[0066] (3) A mixture of carbon dioxide, water and nitrogen is introduced into the cathode chamber, and the flow rates before mixing are 10 sccm, 20 sccm and 70 sccm respectively; the anode atmosphere is nitrogen, and the flow rate is 100 sccm; the power supply applies 1.2V constant voltage to operate the electrolytic cell, and the reaction products are methane, ethane and ethylene.

[0067] It should be noted that the present invention is not limited to the above specific embodiments, but can be in other specific forms. Therefore, different electrolytic cells and devices can be selected according to specific application needs to meet specific reaction conditions and performance requirements.

[0068] The present invention may be summarized in other specific forms that do not violate the spirit and main features of the present invention. Therefore, no matter from which point of view, the above embodiments of the present invention can only be regarded as an explanation of the present invention and cannot limit the present invention. The claims indicate the scope of the present invention, while the above description does not indicate the scope of the present invention. Therefore, any changes within the meaning and scope equivalent to the claims of the present invention should be considered to be included in the scope of the claims.

Claims

1. A system for preparing hydrocarbons by electrolysis of solid oxides driven by solar light, characterized in that: It includes a solar thermal collection system and a light-driven electrolysis reaction system; wherein, The solar thermal collection system is composed of a light concentrator and a light guide device, which is used to collect sunlight and realize conduction and irradiation; the light guide device is in the shape of a hollow tube, and a quartz light guide column is arranged along its axial direction, and a radial spacing is maintained between the light guide column and the tube wall; The light-driven electrolytic reaction system comprises an electrolytic reaction chamber and an intake and exhaust system; a heat-insulating layer is provided outside the intake and exhaust system and the light-guiding device; The electrolytic reaction chamber is a hollow chamber, and the solid oxide electrolytic cell arranged inside the chamber divides the chamber into a cathode chamber and an anode chamber; the solid oxide electrolytic cell is a flat plate structure or a tubular structure, including a cathode layer, an electrolyte layer and an anode layer arranged in sequence, and the cathode layer is composed of a solid oxide semiconductor material with heat collection performance and a non-fully covered metal current collecting layer; The air intake and exhaust system includes two groups of air intake ports and air exhaust ports, and pipelines connected thereto respectively; wherein, the air intake port of the cathode chamber introduces a mixed gas containing carbon dioxide and water through a pipeline, and the air intake port of the anode chamber introduces a carrier gas through a pipeline; the exhaust port of the cathode chamber discharges products containing hydrocarbons through a pipeline, and an air electrode is installed at the end of the pipeline; the exhaust port of the anode chamber discharges a carrier gas containing oxygen through a pipeline, and an air electrode is installed at the end of the pipeline; an external power supply is connected to the two air electrodes respectively, and the air electrodes are connected to the anode layer and the current collecting layer in the cathode layer of the solid oxide electrolytic cell through a wire arranged in the pipeline; the end of the light guide column is aligned with the surface of the cathode layer of the solid oxide electrolytic cell, and the solid oxide semiconductor material absorbs thermal energy in sunlight, and at the same time uses the photogenerated carriers of the semiconductor for light driving and photocatalysis, so as to realize the synergistic electrolysis reaction of light, heat and electricity.

2. The system according to claim 1, characterized in that In the light-guiding device, a vacuum is maintained in the annular tube-shaped cavity between the light-guiding column and the tube wall.

3. The system according to claim 1, characterized in that A gas flow meter and a bubbler are provided on the pipeline for introducing the mixed gas of carbon dioxide and water, and the bubbler is connected to the carbon dioxide gas source and the water source respectively; a gas flow meter is provided on the pipeline for introducing the carrier gas, and the gas flow meter is connected to the carrier gas bottle; a product collection tank is provided on the pipeline for discharging the product.

4. The system according to claim 1, characterized in that The light concentrator is a tower concentrator, a trough concentrator, a Fresnel concentrator or a dish concentrator.

5. The system according to claim 1, characterized in that The external power source is a photovoltaic energy storage power generation device, which is used to apply a voltage less than 1.48V to the air electrode.

6. The system according to claim 1, characterized in that The cross section of the quartz light guide column has the same shape and area as the cathode layer of the solid oxide electrolytic cell.

7. The system according to claim 1, characterized in that The metal current collecting layer is a metal mesh made of gold, silver or platinum.

8. The system according to any one of claims 1 to 7, characterized in that: The end of the light-guiding device has an extended hollow tubular structure, and a radially extending end face flange is arranged at the end of the light-guiding device; the intake and exhaust system as a whole is a hollow plunger structure, and is mounted in the tubular structure at the end of the light-guiding device, and a sealed gap is formed between the two; the length of the intake and exhaust system is smaller than the tubular structure, and the internal space formed by the two is used as an electrolytic reaction chamber; a raised support ring with a relatively slightly smaller radius is provided on the end face of the plunger structure, and the solid oxide electrolytic cell is a flat plate structure and is fixedly mounted on the support ring with its edge; the air inlet and exhaust port of the cathode chamber are arranged on the end face of the plunger structure outside the support ring, and the air inlet and exhaust port of the anode chamber are arranged on the end face of the plunger structure inside the support ring, and each air intake and exhaust pipeline is arranged in the cavity of the plunger structure parallel to the axial direction.

9. The system according to claim 8, characterized in that An end face flange extending radially outward is provided at the outer end of the plunger structure and is fixedly connected to the end face flange of the light guide device through a screw or bolt assembly.

10. The system according to claim 8, characterized in that A radially outwardly extending end face flange is arranged at the other end of the light guide component, and a hollow cylindrical heat-insulating layer is arranged around the outside of the light guide component and is located between the two end face flanges.

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