An electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology

Abstract

The present invention relates to an electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology. Its solid oxide electrolytic cell has an electrolyte layer and a cathode layer and an anode layer respectively located on opposite sides of the electrolyte layer. Among them, the cathode layer and the anode layer are respectively loaded with catalyst components required for the synthesis of chemicals or oil products to couple the high-temperature electrolysis of water vapor and / or carbon dioxide reaction with the high-temperature electrocatalytic reaction, so as to prepare high-pressure hydrogen, syngas and oxygen and directly synthesize chemicals or oil products; the gas control system is used to control the composition, flow rate and pressure of gas reactants and gas products; the thermal management system is used to monitor and control the ambient temperature and electrode temperature of the solid oxide electrolytic cell. According to the electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology of the present invention, water and / or carbon dioxide is used as a raw material, and intermediate products such as hydrogen, carbon monoxide or syngas are prepared by high-temperature and high-pressure electrolysis, and further high-value chemicals or oil products are synthesized.

Description

Technical Field

[0001] The present invention relates to electrochemical synthesis, and more particularly to an electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology. Background Art

[0002] At present, chemicals and oils such as urea, methanol, and synthetic oil are widely used in human industrial production and life, supporting global development. These products are generally obtained through relatively traditional chemical industrial processes. For example, hydrogen or syngas (a mixture of hydrogen and carbon monoxide) is obtained through coal chemical industry or natural gas chemical industry, and then urea is prepared through the synthetic ammonia process, or methanol and other high-value oils and chemicals are prepared using the Fischer-Tropsch reaction. Reasonable utilization of hydrogen and syngas as raw materials has been proven to be able to produce more than 15 different conventional oils and bulk / fine chemicals, with a market value exceeding one trillion yuan.

[0003] However, the preparation of hydrogen and syngas using these traditional processes such as coal chemical industry or natural gas chemical industry requires high investment and input, and is mainly applicable to large industrial plants, not suitable for users with different scale requirements. If a gas generation device that can achieve modular design can be developed, it can meet the needs of users of different scales, and then produce products with higher profits. In addition, the processes of hydrogen production and syngas production using coal, petroleum or natural gas are accompanied by a large amount of carbon dioxide greenhouse gas emissions, posing a great challenge to the environment. If industrial waste carbon dioxide can be used as the sole carbon source for chemicals and oils, its economic value can be enhanced and zero carbon emissions can be achieved. Moreover, the existing processes of synthesizing other chemicals and oils using hydrogen or syngas as raw materials are separated from the gas generation process, which easily leads to excessive additional energy consumption, and also brings problems of storage and transportation of hydrogen and syngas. To achieve the above goals simultaneously, a highly efficient, economical and modular reactor needs to be developed, which can use water and carbon dioxide as raw materials to prepare hydrogen or syngas according to actual scale requirements, and apply the catalysts for preparing chemicals and oils from hydrogen or syngas to the gas generation reactor to simultaneously achieve the synthesis of high-value chemicals and oils.

[0004] Solid oxide high-temperature electrolysis cells (SOECs) can combine the electricity from renewable energy with industrial waste heat to electrochemically reduce carbon dioxide and water efficiently into carbon monoxide, hydrogen, and syngas, and are considered to be one of the most promising energy conversion devices. SOECs also have the characteristics of a fully solid-state ceramic structure, fast reaction rates and corresponding rates, and do not use precious metals. Moreover, hydrogen production by SOEC electrolysis of water has been proven to be capable of being used for the production of hydrogen and carbon monoxide on a relatively large scale. Compared with conventional thermochemical plants (such as syngas production from coal or natural gas), the equipment investment of an electrochemical plant based on SOECs at mass production scale will be significantly reduced, about 50 - 70% of that of a conventional thermochemical plant. On the other hand, using the existing SOEC electrolysis cell structure, through optimization, the electrolysis efficiency can be improved, the cost can be reduced, and a single-pass conversion rate of water and carbon dioxide greater than 50% can be achieved. At the same time, based on SOEC electrolysis cells, the self-regulation of carbon monoxide / hydrogen in syngas can be achieved by adjusting process parameters, so that it can directly enter the subsequent ammonia synthesis, methanol, or Fischer-Tropsch reactors according to the requirements of the products (oil products or chemicals), without further adjustment of the hydrogen-carbon ratio, significantly reducing the comprehensive cost of chemicals and oil products, about 70% of the products produced by conventional thermochemical plants. However, currently, conventional SOEC electrolysis cells belong to low-pressure (<3 bar) electrolysis technology and can only obtain hydrogen or syngas at a relatively low pressure, which is not suitable for directly used in chemical preparation processes such as ammonia synthesis or Fischer-Tropsch reactions. On the other hand, the electrode materials of SOEC electrolysis cells mainly play a catalytic role in the dissociation of water and carbon dioxide and the oxygen evolution reaction, and do not have significant catalytic activity for the chemical preparation process. Therefore, conventional SOEC electrolysis cells are not suitable for directly used in the electrochemical synthesis of high-value chemicals and oil products. Summary of the Invention

[0005] In order to solve the problem that conventional SOEC electrolysis cells in the prior art are not suitable for directly used in the electrochemical synthesis of high-value chemicals and oil products, the present invention provides an electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology.

[0006] The electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology according to the present invention includes a solid oxide electrolysis cell, a gas control system, and a thermal management system. Among them, the solid oxide electrolysis cell has an electrolyte layer and a cathode layer and an anode layer respectively located on opposite sides of the electrolyte layer. Among them, catalyst components required for the synthesis of chemicals or oil products are respectively carried in the cathode layer and the anode layer to couple the high-temperature electrolysis of water vapor and / or carbon dioxide reaction with the high-temperature electrocatalytic reaction, so as to prepare high-pressure hydrogen, syngas, and oxygen and directly synthesize chemicals or oil products; the gas control system is used to control the composition, flow rate, and pressure of gas reactants and gas products; the thermal management system is used to monitor and control the ambient temperature and electrode temperature of the solid oxide electrolysis cell.

[0007] Compared with conventional solid oxide electrolytic cells, the present invention can directly produce hydrogen, syngas, and oxygen with relatively high pressures by simultaneously increasing the feed gas pressures on both sides of the electrolytic cell. In particular, as the electrolyte layer of the SOEC electrolytic cell, it also functions as a "hydrogen pump" or an "oxygen pump" to increase the pressure of the product gas under the applied current. For example, the gas pressure produced by a conventional SOEC electrolytic cell is at atmospheric pressure (1 - 3 bar), while the gas pressure of the present invention can reach 5 - 100 bar. In addition, the present invention can directly utilize hydrogen, syngas, and oxygen on the electrodes to produce high-value chemicals or oil products, improving efficiency and economy while reducing carbon dioxide emissions.

[0008] Preferably, the electrolyte layer can either be an independent diaphragm that is not easily broken or be sintered together with the cathode layer and / or the anode layer as a support structure of the solid oxide electrolytic cell to achieve the pressure-resistant function.

[0009] Preferably, according to the reaction process on the cathode layer and / or the anode layer, the material selected for the electrolyte layer is an inorganic oxide and / or carbonate that can conduct one or more charge carriers among oxygen ions, protons, and carbonate ions. In a preferred embodiment, the material selected for this electrolyte layer is yttria-stabilized zirconia (YSZ) that only has oxygen ion conduction ability, barium zirconium cerium oxide (BZCY) that has both oxygen ion and proton conduction abilities, or a composite material of samarium-doped ceria (SDC) with a high oxygen ion conduction ability and carbonate.

[0010] Preferably, the cathode layer and / or the anode layer have a porous ceramic framework. In a preferred embodiment, the material selected for this cathode layer is a Ni-YSZ composite ceramic, a Ni-BZCY composite ceramic, or a mixture of NiO and a composite electrolyte. In a preferred embodiment, the material selected for this anode layer is a mixture of lanthanum strontium cobalt iron (LSCF) and gadolinium-doped ceria (GDC) (LSCF / GDC), praseodymium barium strontium cobalt iron (PBSCF), or a mixture of LiNiO2 and a composite electrolyte.

[0011] Preferably, a cathode current collector layer is prepared on the surface of the cathode layer for charge collection and reducing the contact impedance. In a preferred embodiment, the material selected for this cathode current collector layer is pure Ni.

[0012] Preferably, in addition to the components with electrocatalytic activity for the dissociation of water vapor and / or carbon dioxide, the cathode layer and the cathode current collector layer also contain active catalysts capable of catalyzing the synthesis process of chemical products or oil products, such as ammonia (Example 1), methanol (Example 2 and Example 3), or methane. The addition techniques of the relevant active catalysts include in-situ generation and post-treatment techniques such as impregnation. In a preferred embodiment, the active catalyst is an Fe catalyst, a CuO-ZnO-ZrO2 catalyst, or a CuO-ZnO-Al2O3 catalyst.

[0013] Preferably, an anode current collector layer is prepared on the surface of the anode layer for charge collection and reducing the contact impedance. In a preferred embodiment, the material selected for the anode current collector layer is LSCF.

[0014] Preferably, in addition to the components with electrocatalytic activity for the oxygen evolution reaction, the anode layer and the anode current collector layer also contain active catalysts capable of realizing the catalytic oxidation process of chemical products or oil products, such as saturated alkanes or unsaturated olefins and alkynes, such as carbon, methane, ethane, etc., such as the electrochemical oxidative dehydrogenation of ethane to ethylene in Example 1, the epoxidation reaction of olefins in Example 2, and the oxidative coupling reaction of alkanes in Example 3. The addition techniques of the relevant active catalysts include in-situ generation and post-treatment techniques such as impregnation. In a preferred embodiment, the active catalyst is an Al2O3 catalyst, an Ag catalyst, or a LiNiO2 catalyst.

[0015] Preferably, the gas control system includes a flow meter and a pressure sensor to respectively adjust and control the flow rate and pressure of the reactant gases and product gases leading to the cathode and the anode, and ensure the pressure balance on both electrode sides.

[0016] Preferably, the gas control system further includes a purification unit for purifying the reactant gases and a separation unit for separating the product gases and the unreacted reactant components.

[0017] Preferably, the thermal management system includes a solid oxide electrolysis cell control unit for monitoring and regulating the ambient temperature, the cathode layer temperature, and the anode layer temperature of the solid oxide electrolysis cell, and feeding back the temperature difference between the cathode layer and the anode layer to the gas control system for temperature adjustment by adjusting the flow rate of the reactant gases, so as to ensure that the temperatures on both sides are the same.

[0018] Preferably, the thermal management system further includes a preheating unit for preheating the reactant gases and a recovery unit for recovering the waste heat of the product gases.

[0019] The electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology according to the present invention uses water and / or carbon dioxide as raw materials, prepares intermediate products such as hydrogen, carbon monoxide or syngas through high-temperature and high-pressure electrolysis, and further synthesizes high-value chemicals or oil products. This technology has the characteristics of wide application range and sufficient raw material resources, and can directly optimize the process and construct production devices for users with various different product and scale requirements. Especially for regions rich in clean energy such as nuclear power, hydropower, wind power, and solar energy, the efficient conversion and storage of energy and the reduction of carbon emissions can be widely achieved through the device described in the present invention. In addition, the present invention also has the characteristics of system modular composition, simple operation, high safety, and small investment. Brief Description of the Drawings

[0020] Figure 1 It is a schematic structural diagram of an electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology according to a preferred embodiment of the present invention. Detailed Embodiments

[0021] The following combines the drawings to give the preferred embodiments of the present invention and describes them in detail.

[0022] Embodiment 1

[0023] As Figure 1 shown, the electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology according to a preferred embodiment of the present invention includes a solid oxide electrolyzer 1, a gas management system 2, and a thermal management system 3.

[0024] The solid oxide electrolyzer 1 is used to prepare high-pressure hydrogen, syngas and oxygen and directly synthesize chemicals or oil products. It is composed of a dense electrolyte layer 11, a cathode layer 12, a cathode current collector layer 13, an anode layer 14, and an anode current collector layer 15. The dense electrolyte layer 11 is a stable and dense electrolyte layer, and the selected material is yttria-stabilized zirconia (YSZ) that only has oxygen ion conduction ability. The cathode layer 12 is a porous layer, and the selected material is Ni-YSZ composite ceramics. The cathode current collector layer 13 is made of pure Ni. The formed and sintered cathode layer 12 and cathode current collector layer 13 can simultaneously introduce the Fe catalyst for ammonia synthesis reaction by solution impregnation method. The anode layer 14 is a porous layer, and the selected material is a mixture of lanthanum strontium cobalt iron (LSCF) and gadolinium-doped ceria (GDC) (LSCF / GDC). The material used for the anode current collector layer 15 is LSCF. The materials used for the anode layer 14 and the anode current collector layer 15 can be doped with an appropriate amount of Al2O3 catalyst for the electrochemical oxidative dehydrogenation of ethane to ethylene by mechanical mixing method.

[0025] The gas management system 2 is used to control the composition, flow rate, and pressure of the reactant gas and the product gas, and includes a gas flow rate and pressure control unit 21, a purification unit 22 for purifying the reactant gas, and a separation unit 23 for separating the product gas and the unreacted reactant components. Among them, the gas flow rate and pressure control unit 21 includes a flow meter and a pressure sensor, which respectively adjust and control the flow rate and pressure of the reactant gas and the product gas leading to the cathode and the anode, and ensure the pressure balance on both electrode sides.

[0026] The thermal management system 3 includes a solid oxide electrolytic cell control unit 31, a preheating unit 32 for preheating the reactant gas, and a recovery unit 33 for recovering the waste heat of the product gas. Among them, the solid oxide electrolytic cell control unit 31 is used to monitor and regulate the ambient temperature, cathode layer temperature, and anode layer temperature of the solid oxide electrolytic cell 1, feedback the temperature difference between the cathode layer and the anode layer to the gas management system 2, and then adjust the temperature by regulating the flow rate of the reactant gas to ensure that the temperatures on both sides are the same.

[0027] The main reactions occurring on the cathode are: H2O + 2e - → H2 + O 2- and 3H2 + N2 → 2NH3. The main reactions occurring on the anode are: 2O 2- - 4e - → O2, C2H6 + 0.5O2 → C2H4 + H2O, C2H6 + O 2- → C2H4 + H2O + 2e - . The pressures on both the cathode and anode sides are 100 bar, and the reaction temperature is 1000 °C.

[0028] Example 2

[0029] Different from Example 1, the material of the dense electrolyte layer 11 is selected as barium zirconium cerium oxide (BZCY) which has both oxygen ion and proton conduction capabilities. The material selected for the cathode layer 12 is Ni - BZCY composite ceramic, and the CuO - ZnO - ZrO2 catalyst for the synthesis gas to methanol reaction is incorporated into the cathode layer 12 and the cathode current collector layer 13. The material selected for the anode layer 14 is praseodymium barium strontium cobalt iron (PBSCF), and the Ag catalyst for the olefin epoxidation reaction is added to the anode layer 14 and the anode current collector layer 15.

[0030] The main reactions occurring on the cathode are: 2H + + - 2e - → H2, CO + 2H2 → CH3OH, CO2 + 3H2 → CH3OH + H2O, CO2 + 2e - → CO + O 2- and H2O + 2e - → H2 + O 2-The reactions occurring at the anode are mainly: 2H2O - 4e - →4H + + O2 and C2H4 + 0.5O2 → C2H4O. The pressures on both the cathode and anode sides are 1 bar, and the reaction temperature is 500 °C.

[0031] Example 3

[0032] Different from Example 1 and Example 2, the material of the dense electrolyte layer 11 is selected as a composite material of samarium-doped ceria (SDC) with high oxygen ion conductivity and carbonate. The material selected for the cathode layer 12 is a mixture of NiO and the composite electrolyte, and a CuO-ZnO-Al2O3 catalyst for the synthesis of methanol from syngas is incorporated into the cathode layer 12 and the cathode current collector layer 13. The material selected for the anode layer 14 is a mixture of LiNiO2 and the composite electrolyte, and a LiNiO2 catalyst for the oxidative coupling of alkanes is added to the anode layer 14 and the anode current collector layer 15.

[0033] The reactions occurring at the cathode are mainly: CO2 + 2e - → CO + O 2- 、H2O + 2e - → H2 + O 2- 、CO + 2H2 → CH3OH and CO2 + 3H2 → CH3OH + H2O. The reactions occurring at the anode are mainly: 2O 2- - 4e - → O2 and 2CH4 + O2 → C2H4 + 2H2O. The pressures on both the cathode and anode sides are 10 bar, and the reaction temperature is 750 °C.

[0034] In the present invention, the high-temperature and high-pressure electrolysis of water and / or the reaction with carbon dioxide are endothermic reactions, and the heat absorption is related to the current magnitude of the electrolysis reaction and the ambient temperature. The reactions such as the preparation of hydrogen for ammonia synthesis or the synthesis of methanol from syngas occurring at the cathode, and the partial oxidation of alkanes occurring at the anode are all exothermic reactions. Therefore, by adjusting the gas flow rates on both electrodes to control the rate of the catalytic reaction, and at the same time adjusting the current of the high-temperature and high-pressure electrolysis reaction and the magnitude of the ambient temperature, the heat balance in the entire electrochemical synthesis device can be finally achieved, and the energy utilization efficiency of the entire system can be improved.

[0035] The mechanical, electrical parts, electronic components, materials, etc. used in the electrochemical synthesis device based on the high-temperature and high-pressure electrolysis technology according to the present invention are all commercially available.

[0036] The above are only the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Various changes can be made to the above embodiments of the present invention. That is, all simple, equivalent changes and modifications made according to the claims and the content of the specification of the present invention application fall within the scope of protection of the claims of the present invention patent. Those not described in detail in the present invention are all conventional technical contents.

Claims

1. An electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology, characterized in that, The electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology includes a solid oxide electrolytic cell, a gas control system, and a thermal management system. Among them, the solid oxide electrolytic cell has an electrolyte layer, and a cathode layer and an anode layer respectively located on opposite sides of the electrolyte layer. Among them, the cathode layer and the anode layer respectively carry catalyst components required for the synthesis of chemicals or oils to couple the high-temperature electrolysis of water vapor and / or carbon dioxide reaction with the high-temperature electrocatalytic reaction, so as to prepare high-pressure hydrogen, syngas and oxygen and directly synthesize chemicals or oils. Among them, the catalyst component in the cathode layer is an Fe catalyst, a CuO-ZnO-ZrO2 catalyst or a CuO-ZnO-Al2O3 catalyst, and the catalyst component in the anode layer is an Al2O3 catalyst, an Ag catalyst or a LiNiO2 catalyst; the gas control system is used to control the composition, flow rate and pressure of gas reactants and gas products, and the gas pressures of the cathode layer and the anode layer are respectively between 5 bar and 100 bar; the thermal management system is used to monitor and control the ambient temperature and electrode temperature of the solid oxide electrolytic cell.

2. The electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology according to claim 1, wherein, According to the reaction process on the cathode layer and / or the anode layer, the material selected for the electrolyte layer is an inorganic oxide and / or carbonate that can conduct one or more charge carriers among oxygen ions, protons and carbonate ions.

3. The electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology according to claim 1, characterized in that, A cathode current collector layer is prepared on the surface of the cathode layer for charge collection and reduction of contact impedance.

4. The electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology according to claim 3, characterized in that, In addition to the components with electrocatalytic activity for the dissociation of water vapor and / or carbon dioxide, the cathode layer and the cathode current collector layer also contain active catalysts capable of catalyzing the synthesis of chemicals or oils.

5. The electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology according to claim 1, wherein, An anode current collector layer is prepared on the surface of the anode layer for charge collection and reduction of contact impedance.

6. The electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology according to claim 5, characterized in that, In addition to the components with electrocatalytic activity for the oxygen evolution reaction, the anode layer and the anode current collector layer also contain active catalysts capable of realizing chemicals or oils.

7. The electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology according to claim 1, characterized in that, The gas control system includes a flow meter and a pressure sensor, which respectively adjust and control the flow rate and pressure of the reactant gas and the product gas leading to the cathode and the anode, and ensure the balance of the pressures on both electrode sides.

8. The electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology according to claim 7, wherein, 9. The electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology according to claim 1, wherein, The gas control system also includes a purification unit for purifying the reactant gas and a separation unit for separating the product gas from the unreacted reactant components.

10. The electrochemical synthesis device based on high-temperature and high-pressure electrolysis technology according to claim 1, wherein The thermal management system includes a solid oxide electrolytic cell control unit, which is used to monitor and regulate the ambient temperature, the cathode layer temperature and the anode layer temperature of the solid oxide electrolytic cell, and feeds back the temperature difference between the cathode layer and the anode layer to the gas control system, and then adjusts the temperature by adjusting the flow rate of the reactant gas to ensure that the temperatures on both sides are the same. The thermal management system also includes a preheating unit for preheating the reactant gas and a recovery unit for recovering the waste heat of the product gas.

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