Carbon dioxide direct methanation device and system

Abstract

The invention provides a carbon dioxide direct methanation device and system. The device comprises a first reactor, and the first reactor is configured to be capable of heating low-temperature fuel mixed gas entering a second gas channel and conveying the heated low-temperature fuel mixed gas into a second reactor while synthesizing methane from mixed gas entering a first gas channel; the second reactor and the first reactor are jointly arranged in the first sealing chamber, and a heating piece is arranged in the first sealing chamber close to the second reactor; the second reactor comprises a fuel channel and an air channel; the fuel channel is communicated with the second gas channel, and the output end is communicated with the first gas channel; and the second reactor is configured to electrolyze the heated fuel mixed gas and convey the mixed gas generated by electrolysis in the fuel channel into the first gas channel. The raw material is mainly carbon dioxide, the carbon reduction target can be achieved, meanwhile, methane fuel can be efficiently converted, no extra catalyst is needed, and the operation life is long.

Description

Technical Field

[0001] The present disclosure relates to the technical field of carbon dioxide methanation devices, and in particular to a carbon dioxide direct methanation device and system. Background Art

[0002] Solid oxide fuel cells are fuel cells that use solid oxides as electrolytes and operate at high temperatures. Methanation reactors mainly use the process of converting syngas (a mixture of carbon monoxide and hydrogen) into methane.

[0003] For example, a temperature-self-maintaining carbon dioxide and water vapor co-electrolysis device is disclosed in a Chinese patent application (CN107699915A). The device includes a reactor, a fuel electrode chamber and a tubular solid oxide electrolysis cell built in the reactor, the fuel electrode chamber is sealed and connected to the tubular solid oxide electrolysis cell, an air electrode chamber is arranged outside the tubular solid oxide electrolysis cell, and an annular thermal insulation material is arranged around the fuel electrode chamber and the tubular solid oxide electrolysis cell in the reactor. Among them, the tubular structure solid oxide fuel cell has a small active reaction area, low electrolysis efficiency, and is difficult to scale. Chinese patent application (CN116526684A) discloses an electric energy storage device and system, which uses a flat tube solid oxide electrolysis cell to convert carbon dioxide into carbon monoxide and oxygen, and uses a flat tube solid oxide fuel cell to generate electricity from carbon monoxide, but the patent application does not involve the methanation process. As a result, the electrolysis products of solid oxide fuel cells cannot be effectively utilized at present, and the excess energy generated is greatly wasted.

[0004] In addition, the current traditional thermal catalytic methanation reactor uses a fixed bed filled with granular catalyst or a plate heat exchange structure filled with granular catalyst materials, which has problems such as complex methanation process, difficult control, and easy high-temperature deactivation of the catalyst.

[0005] Therefore, in order to effectively utilize unstable and redundant energy storage, it is necessary to provide a device that can directly synthesize methane from the gas produced by the co-electrolysis reaction of carbon dioxide. Summary of the invention

[0006] The present disclosure provides a carbon dioxide direct methanation device and system to at least solve one of the technical problems existing in the prior art.

[0007] According to a first aspect of the present disclosure, there is provided a carbon dioxide direct methanation device, comprising:

[0008] The first reactor comprises a first gas channel and a second gas channel which are not interconnected, wherein the first reactor is configured to synthesize methane from the mixed gas entering the first gas channel and heat the low-temperature fuel mixed gas entering the second gas channel and transport the mixed gas to the second reactor;

[0009] The second reactor is disposed together with the first reactor in the first sealed chamber and the two are disposed far away from each other, and a heating element is disposed in the first sealed chamber near the second reactor; the second reactor is a solid oxide fuel cell or a stack structure formed by stacking a plurality of battery units;

[0010] The second reactor includes a fuel channel and an air channel; the input end of the fuel channel is connected to the second gas channel, and the output end is connected to the first gas channel; the second reactor is configured to electrolyze the heated fuel mixture and transport the mixture generated by electrolysis in the fuel channel to the first gas channel.

[0011] In one possible implementation, the output end of the fuel channel is connected to the first gas channel via a water removal device;

[0012] The heating element is a resistance wire.

[0013] In one embodiment, the first reactor comprises a plurality of synthetic methane units stacked in sequence in a vertical direction;

[0014] The synthetic methane unit comprises a support body and a flow channel sheet, wherein a plurality of the first gas channels are arranged inside the support body; the flow channel sheet is sealed and stacked on the surface of the support body, and a plurality of the second gas channels are formed on the flow channel sheet.

[0015] In one embodiment, the material of the support is Ni-YSZ, wherein YSZ is 2mol%-10mol% Y2O3-stabilized ZrO3; the mass percentage of Ni is 40wt%-60wt%, and the mass percentage of YSZ is 40wt%-60wt%;

[0016] The porosity of the support is 50-80%;

[0017] A dense insulating layer is also provided between the support body and the flow channel sheet in a sealed manner, and the dense insulating layer is coated on the outside of the support body;

[0018] The first gas channel is arranged perpendicular to the second gas channel;

[0019] The material of the dense insulating layer is YSZ, GDC, and the thermal expansion coefficient is 9.0×10 -6 ~20.0×10 -6 / ℃ a mixture of one or more sealing glass materials.

[0020] In one embodiment, the second reactor comprises an anode, an active anode, an electrolyte, a barrier layer and a cathode, wherein the anode is NiO-3YSZ, the active anode is NiO-8YSZ, the electrolyte is 8YSZ, the barrier layer is GDC, and the cathode is LSCF / GDC.

[0021] In one possible implementation manner, the temperature of the low-temperature fuel mixture before heating is 20-40° C.;

[0022] The fuel mixed gas is a mixture of carbon dioxide, water and hydrogen, and the flow ratio of the three is 1-3:1-3:1.

[0023] In one possible implementation, a pressure regulating valve and a mass flow meter are sequentially provided on the pipe connected to the air inlet end of the second gas channel along the gas delivery direction; a pressure regulating valve and a mass flow meter are sequentially provided on the pipe connected to the air inlet end of the air channel along the gas delivery direction;

[0024] The fuel mixture is a mixture of carbon dioxide, water and hydrogen, and the flow ratio of the three is 2:2:1 or 3:1:1 or 1:3:1.

[0025] According to a second aspect of the present disclosure, there is provided a carbon dioxide direct methanation device, comprising:

[0026] A first reactor is independently arranged in the second sealed chamber, the first reactor comprises a first gas channel and a third gas channel which are not connected to each other, the third gas channel is used to circulate heated air so that the first reactor reaches a methanation temperature; the first reactor is configured to synthesize methane from the mixed gas entering the first gas channel at the methanation temperature;

[0027] A second reactor is independently arranged in the third sealed chamber and a heating element is arranged in the third sealed chamber; the second reactor is a solid oxide fuel cell or a stack structure formed by stacking a plurality of battery units;

[0028] The second reactor includes a fuel channel and an air channel, the output end of the fuel channel is connected to the first gas channel, and the air outlet end of the air channel is connected to the third gas channel; wherein the air channel is used to heat the air flowing therein and output the heated air to the third gas channel; the second reactor is configured to electrolyze the fuel gas and transport the mixed gas generated by the electrolysis in the fuel channel to the first gas channel.

[0029] In one possible implementation, the output end of the fuel channel is connected to the input end of the first gas channel through a water removal device;

[0030] The heating element is a resistance wire.

[0031] In one embodiment, the first reactor comprises a plurality of synthetic methane units stacked in sequence in a vertical direction;

[0032] The synthetic methane unit comprises a support body and a flow channel sheet, wherein a plurality of the first gas channels are arranged inside the support body; the flow channel sheet is sealed and stacked on the surface of the support body, and a plurality of the third gas channels are formed on the flow channel sheet.

[0033] In one embodiment, the material of the support is Ni-YSZ, wherein YSZ is 2mol%-10mol% Y2O3-stabilized ZrO3; the mass percentage of Ni is 40wt%-60wt%, and the mass percentage of YSZ is 40wt%-60wt%;

[0034] The porosity of the support is 50-80%;

[0035] A dense insulating layer is also provided between the support body and the flow channel sheet in a sealed manner, and the dense insulating layer is coated on the outside of the support body;

[0036] The first gas channel and the third gas channel are arranged perpendicularly;

[0037] The material of the dense insulating layer is YSZ, GDC, and the thermal expansion coefficient is 9.0×10 -6 ~20.0×10 -6 / ℃ a mixture of one or more sealing glass materials.

[0038] In one possible implementation manner, the fuel gas flowing in the fuel channel is a mixture of carbon dioxide, water vapor and hydrogen, and the flow ratio of the three is 1 to 3:1 to 3:1;

[0039] The air flow rate in the air channel is 3 to 20 L / min.

[0040] In one embodiment, the second reactor comprises an anode, an active anode, an electrolyte, a barrier layer and a cathode, wherein the anode is NiO-3YSZ, the active anode is NiO-8YSZ, the electrolyte is 8YSZ, the barrier layer is GDC, and the cathode is LSCF / GDC.

[0041] In one embodiment, a pressure regulating valve and a mass flow meter are sequentially provided on the pipeline connected to the air inlet end of the air channel along the gas delivery direction; a pressure regulating valve and a mass flow meter are sequentially provided on the pipeline connected to the input end of the fuel channel along the gas delivery direction;

[0042] The fuel gas flowing in the fuel channel is a mixture of carbon dioxide, water vapor and hydrogen, and the flow ratio of the three is 2:2:1 or 3:1:1 or 1:3:1.

[0043] According to a third aspect of the present disclosure, there is provided a carbon dioxide direct methanation system, comprising a power supply device and also comprising any of the above-mentioned carbon dioxide direct methanation devices in one possible implementation manner.

[0044] Compared with the prior art, the advantages of the present application are: 1) The raw material of the present application is mainly carbon dioxide, which can achieve the carbon reduction target and can be converted into methane fuel with high efficiency. No additional catalyst is required and the operating life is long. 2) In the device of the present application, the fuel mixture introduced is low temperature, and the gas temperature can be increased by passing through the first reactor, thereby improving the reaction efficiency of co-electrolysis, and at the same time, the first reactor is cooled to a temperature suitable for methane synthesis. The integrated design can save space and reduce energy consumption. 3) The waste heat of air tail gas can be effectively utilized in the device of the present application, and there is no need to heat the first reactor additionally, saving energy consumption. 4) The support body in the first reactor and the anode material in the second reactor of the present application are substantially the same, and can share the same production line, with low production costs. 5) In the device of the present application, the device can be suitable for large-scale electrolysis synthesis of methane by adding a stack unit.

[0045] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The above and other objects, features and advantages of the exemplary embodiments of the present disclosure will become readily understood by reading the detailed description below with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present disclosure are shown in an exemplary and non-limiting manner, in which:

[0047] In the drawings, the same or corresponding reference numerals represent the same or corresponding parts.

[0048] Figure 1 A schematic cross-sectional view of a support body and a dense insulating layer according to an embodiment of the present disclosure is shown;

[0049] Figure 2 A first structural schematic diagram of a synthetic methane unit constituting a first reactor in a first device of an embodiment of the present disclosure is shown;

[0050] Figure 3 Shows Figure 2 Side view of Figure 1 ;

[0051] Figure 4 Shows Figure 2 Side view of Figure 2 ;

[0052] Figure 5 A second structural schematic diagram of a synthetic methane unit constituting a first reactor in the first device of an embodiment of the present disclosure is shown;

[0053] Figure 6 Shows Figure 5 Schematic side view of

[0054] Figure 7 A first structural schematic diagram of a synthetic methane unit constituting a first reactor in a second device of an embodiment of the present disclosure is shown;

[0055] Figure 8 A second structural schematic diagram of a synthetic methane unit constituting a first reactor in a second device of an embodiment of the present disclosure is shown;

[0056] Fig. 9 Shows Figure 8 Schematic side view of

[0057] Fig.10 The structure of the first reactor of the present invention is shown in FIG. Figure 1 ;

[0058] Fig.11 Shows Fig.10 Explosion diagram of

[0059] Fig.12 Shows Fig.10 Cross-sectional view of Figure 1 ;

[0060] Fig.13 Shows Fig.10 Cross-sectional view of Figure 2 ;

[0061] Fig.14 A first structural schematic diagram of a single cell of a second reactor of an embodiment of the present disclosure is shown;

[0062] Fig.15 Shows Fig.14 Front view of the diagram;

[0063] Fig.16 A second structural schematic diagram of a single cell of a second reactor of an embodiment of the present disclosure is shown;

[0064] Fig.17 A schematic structural diagram of a first carbon dioxide direct methanation device according to an embodiment of the present disclosure is shown;

[0065] Fig.18A schematic structural diagram of a second carbon dioxide direct methanation device according to an embodiment of the present disclosure is shown.

[0066] Explanation of reference numerals in the figure: first reactor 1, second reactor 2, first sealed chamber 3, heating element 4, water removal device 5, thermocouple 6, flow meter 7, pressure regulating valve 8, thermal insulation material 9;

[0067] Support body 11, flow channel sheet 12, first gas channel 13, dense insulating layer 14, second gas channel 15, third gas channel 16, first connecting plate 17, second connecting plate 18, fixing plate 19, first connecting channel 171, second connecting channel 181;

[0068] Anode 21 , active anode 22 , electrolyte 23 , barrier layer 24 , cathode 25 , flow channel plate 26 , fuel channel 211 , and air channel 261 . DETAILED DESCRIPTION

[0069] In order to make the purpose, features, and advantages of the present disclosure more obvious and easy to understand, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.

[0070] This application can couple renewable electricity through solid oxide fuel cells, utilize unstable and redundant energy storage, and directly convert carbon dioxide / water into CO / H2 synthesis gas by co-electrolysis, thereby achieving carbon reduction while synthesizing the CO / H2 produced by electrolysis into methane fuel. In addition, the oxygen ions in the fuel can also be oxidized to obtain high-purity oxygen.

[0071] Based on this, the present application provides a carbon dioxide direct methanation device (hereinafter referred to as "device"). The device mainly includes two reactors, which are respectively set as a first reactor 1 and a second reactor 2.

[0072] In the present application, the first reactor 1 is a methane synthesis device. The first reactor 1 includes a plurality of methane synthesis units stacked in sequence in a vertical direction, and the methane synthesis unit includes a support body 11 and a flow channel sheet 12. Figure 1-9 As shown, the support body 11 is provided with a plurality of first gas channels 13 running through both ends. The shapes of the first gas channels 13 include but are not limited to circular, square or triangular shapes that can allow gas to pass through.

[0073] The material of the support 11 is Ni-YSZ (nickel-yttria-stabilized zirconia), wherein YSZ is 2mol%-10mol% Y2O3-stabilized ZrO3; the mass percentage of Ni is 40wt%-60wt%, and the mass percentage of YSZ is 40wt%-60wt%; the porosity of the support material is 50-80%.

[0074] The outer side of the support body 11 is surrounded by a dense insulating layer 14, and the material of the dense insulating layer 14 is YSZ, GDC (gadolinium-doped cerium oxide) and a thermal expansion coefficient of 9.0×10 -6 ~20.0×10 -6 / ℃ sealing glass material with one or more materials mixed.

[0075] like Figure 2-9 As shown, the flow channel sheet 12 is sealed and stacked on the surface of the dense insulating layer 14 outside the support body 11. A plurality of second gas channels 15 or third gas channels 16 are formed on the flow channel sheet 12, which pass through both ends. The second gas channel 15 is used to circulate the fuel mixture, and the third gas channel 16 is used to circulate the heated air. The following will be explained according to the specific application device, which will not be expanded here. The flow channel sheet 12 can be processed by etching or stamping. The structure of the flow channel sheet 12 is as follows Figure 2 , Figure 5 The material of the flow channel plate 12 includes but is not limited to materials with a temperature resistance of 700° C. such as SUS300, SUS400 and ceramics, and can also be materials with good thermal conductivity such as copper.

[0076] Among them, the gas channels (including the second gas channel 15 or the third gas channel 16) formed on the flow channel plate 12 are arranged perpendicular to the direction of the first gas channel 13. For example, the first gas channel 13 is arranged along the length direction (X direction) of the support body 11, and the gas channel formed on the flow channel plate 12 is arranged along the width direction (Y direction) of the support body; and the two gas channels are not connected to each other.

[0077] In the present application, the first reactor 1 is configured to synthesize methane from the mixed gas entering the first gas channel 13. This is because the material of the support 11 is Ni-YSZ, which can promote the mixed gas (including CO, H2 and CO2) to move towards the direction of synthesizing methane. The use of the support Ni-YSZ material to methanize the mixed gas has been disclosed in the prior art and will not be repeated here.

[0078] like Figure 10-13As shown, the present application provides a specific structural schematic diagram of the first reactor 1. Specifically, the first reactor 1 includes three synthetic methane units that are sealed and stacked in sequence in the vertical direction, as well as a first connecting plate 17, a second connecting plate 18 and a fixed plate 19. The synthetic methane unit includes a support body 11 and a flow channel sheet 12. The second connecting plate 18 is sealed and connected to the front and rear sides of the support body 11, and a second connecting channel 181 is formed on the second connecting plate 18. The first end of the second connecting channel 181 is sealed and connected to the third pipeline 131 / the fourth pipeline 132, and the second end of the second connecting channel 181 is sealed and connected to the first gas channel 13 of the support body 11. The first connecting plate 17 is sealed and connected to the front and rear sides of the flow channel sheet 12, and a first connecting channel 171 is formed on the first connecting plate 17; the first end of the first connecting channel 171 is sealed and connected to the first pipeline 151 / the second pipeline 152, and the second end of the first connecting channel 171 is sealed and connected to the second gas channel 15 or the third gas channel 16 of the flow channel sheet 12. A fixing plate 19 is provided on the upper and lower sides of the flow channel plate 12 and the support body 11 , respectively. The fixing plates 19 are fixedly connected by screws.

[0079] In the present application, the second reactor 2 is a co-electrolysis device. Specifically, the second reactor 2 is a solid oxide fuel cell or a plurality of battery units integrated with a stack structure (a stack structure formed by stacking a plurality of solid oxide fuel cell units). The structure of the second reactor 2 can be a flat plate type, a round tube type, and a flat tube type. The solid oxide fuel cell and the stack structure can adopt existing known technologies, which will not be repeated here.

[0080] Preferably, Figure 14-15 A single cell cross-sectional structure is provided; the single cell comprises an anode 21, an active anode 22, an electrolyte 23, a barrier layer 24 (i.e., an isolation layer), and a cathode 25, wherein the anode is NiO-3YSZ, the active anode is NiO-8YSZ, the electrolyte is 8YSZ, the barrier layer is GDC, and the cathode is LSCF / GDC; a plurality of fuel channels 211 running through both ends are provided in the anode 21 for circulating fuel gas. In addition, the single cell also comprises a flow channel plate 26, in which an air channel 261 is formed for circulating air.

[0081] Fig.16 Another single cell cross-sectional structure is provided, from Fig.16 It can be seen that the single cell includes a flow channel plate 26, an anode 21, an active anode 22, an electrolyte 23, a barrier layer 24 and a cathode 25. The anode is NiO-3YSZ, the active anode is NiO-8YSZ, the electrolyte is 8YSZ, the barrier layer is GDC, and the cathode is LSCF / GDC. Fig.16In the embodiment, the flow channel plate 26 is provided with a plurality of fuel channels 211 on the side close to the anode 21 for circulating the fuel; and an air channel 261 is provided on the side away from the anode (close to the cathode) for circulating the air.

[0082] In the present application, the second reactor 2 can electrolyze the fuel mixture or fuel gas and air entering the fuel channel 211 to produce the synthesis gas required for the first reactor 1 to synthesize methane.

[0083] In the present application, in the second reactor 2, large-scale electrolysis can be performed by adding fuel cell units, thereby achieving large-scale synthesis of methane.

[0084] In the present application, the anode and active anode materials of the second reactor 2 are substantially the same as the support material of the first reactor. Therefore, a common production line can be used during production to reduce production costs.

[0085] In this application, two different structures of carbon dioxide direct methanation devices are provided, both of which can realize the integration of co-electrolysis and methane synthesis to reduce energy consumption. Specifically:

[0086] The first device: Fig.17 As shown, a carbon dioxide direct methanation device comprises:

[0087] The first reactor 1 comprises a first gas channel 13 and a second gas channel 15 which are not connected to each other. The second gas channel 15 is used to heat the low-temperature fuel mixed gas entering the second gas channel 15 and cool the first reactor 1 to a methanation temperature. The first reactor 1 is configured to synthesize methane from the mixed gas entering the first gas channel 13 and heat the low-temperature fuel mixed gas entering the second gas channel 15 and transport it to the second reactor 2.

[0088] The second reactor 2 is disposed together with the first reactor 1 in the first sealed chamber 3 and the two are disposed far away from each other, and a heating element 4 is disposed in the first sealed chamber 3 near the position of the second reactor; the second reactor 2 is a solid oxide fuel cell or a stack structure formed by stacking a plurality of solid oxide fuel cell units;

[0089] The second reactor 2 includes a fuel channel 211 and an air channel 261; the input end of the fuel channel 211 is connected to the second gas channel 15, and the output end is connected to the first gas channel 13; the second reactor 2 is configured to electrolyze the heated fuel mixture and transport the mixture generated by the electrolysis in the fuel channel 211 to the first gas channel 13.

[0090] In this device, the first reactor 1 and the second reactor 2 are arranged in the same first sealed chamber 3, and the two are arranged far away from each other. A heating element 4 is arranged on the inner wall surface of the first sealed chamber 3 near the second reactor 2, and the heating element 4 can make the temperature of the second reactor 2 reach the electrolysis temperature. Since the first reactor 1 is also arranged in the same sealed chamber, it will inevitably be affected by the heating element 4, so in order to cool down the first reactor 1 to the methanogenic temperature (i.e., the temperature required for synthesizing methane). During operation, the low-temperature fuel mixture is first introduced into the first reactor 1 (the fuel mixture can be a mixture of carbon dioxide, water and hydrogen); the first reactor 1 can be cooled down to the methanogenic temperature while the fuel mixture is heated, wherein the heated fuel mixture enters the second reactor 2, and the second reactor 2 is electrolyzed to produce synthesis gas. Since the fuel mixture has been heated before entering the second reactor 2, the reaction efficiency of the co-electrolysis can be improved. Therefore, this device realizes the integrated design of co-electrolysis and methane synthesis, which can save space and reduce energy consumption.

[0091] The second reactor 2 electrolyzes the fuel mixture at the fuel electrode side to generate CO and H2, and CO, H2, water vapor that does not participate in the reaction, and the remaining CO2 are discharged from the output end of the fuel channel 211.

[0092] In the device, an existing electric furnace can be used to form a sealed chamber.

[0093] In this application, if Fig.17 As shown, the output end of the fuel channel 211 is connected to the first gas channel 13 through a dehydration device 5 disposed outside the first sealed chamber 3. The dehydration device 5 can be implemented using currently known technologies, for example, physical adsorption or chemical adsorption can be used to add a physical adsorbent or a chemical adsorbent in a sealed container to achieve the purpose of removing water vapor. Physical adsorbents include but are not limited to activated carbon and molecular sieves. Chemical adsorbents include but are not limited to desiccant and dehumidifier.

[0094] Therefore, the mixed gas composed of CO, H2, water vapor and CO2 output from the fuel channel 211 of the second reactor 2 first passes through a water removal device to filter out the water vapor in the mixed gas, and the remaining mixed gas composed of CO, H2 and CO2 enters the first gas channel 13 to synthesize methane.

[0095] In this device, since the anode of the second reactor 2 is NiO-3YSZ and the active anode is NiO-8YSZ, in order to electrolyze the fuel mixture entering the fuel channel 211, the anode and the active anode need to be reduced first. Therefore, before the low-temperature fuel mixture is introduced into the first reactor 1, H2 is first introduced into the fuel channel 211 of the second reactor 2 from the second gas channel 15 of the first reactor 1 to reduce the anode to Ni-3YSZ and the active anode to Ni-8YSZ. After 2 to 6 hours of introducing H2, the low-temperature fuel mixture is introduced into the second gas channel 15 of the first reactor 1. This enables the second reactor 2 to electrolyze the heated fuel mixture smoothly.

[0096] The voltage of the second reactor 2 can also be detected in real time to determine whether the battery in the second reactor is completely restored. For example, when the voltage of the second reactor remains unchanged, it indicates that the battery in the second reactor is completely restored.

[0097] In the present application, since the main raw material of the fuel mixture is carbon dioxide, the carbon reduction target can be achieved, and at the same time, it can be converted into methane fuel with high efficiency. No additional catalyst is required, and the operating life is long. In the device of the present application, the low-temperature fuel mixture is first passed through the first reactor 1 to increase the gas temperature, improve the reaction efficiency of co-electrolysis, and at the same time cool the first reactor 1 to a temperature suitable for methane synthesis. The integrated design can save space and reduce energy consumption.

[0098] Preferably, in the present device, the heating element 4 is a resistance wire, which is laid on the inner wall surface of the first sealed chamber 3. Fig.17 As shown, the heating element 4 is arranged on the right half of the inner wall surface of the first sealed chamber 3. The second reactor 2 in the first sealed chamber 3 is heated by a resistance wire to reach the electrolysis temperature. For example, the required working temperature of the second reactor 2 is 600-900°C. In order to accurately control the temperature, a thermocouple 6 is also arranged on the second reactor 2, and the temperature of the second reactor 2 measured in real time by the thermocouple 6 is used to adjust the heating temperature of the resistance wire.

[0099] Preferably, in the present device, the operating temperature required for the first reactor 1 to synthesize methane is 500-600°C, which is lower than the temperature of the second reactor 2. Therefore, the temperature of the low-temperature fuel mixture before heating (i.e., the temperature when entering the second gas channel) is 20-40°C, and the low-temperature fuel mixture can cool down the first reactor 1 when heated. Further, the first reactor 1 can be kept within the operating temperature range by controlling the flow rate of the fuel mixture. That is, the fuel mixture is a mixture of carbon dioxide, water and hydrogen, and the flow ratio of the three is 1-3:1-3:1; preferably 2:2:1 or 3:1:1 or 1:3:1. For example, a flow meter 7 and a pressure regulating valve 8 can be set on the pipeline entering the second gas channel 15 to control and adjust the flow rate of the fuel mixture.

[0100] like Fig.17 As shown, a layer of heat-insulating material 9 is provided around the inner wall of the first sealed chamber 3, and a resistance wire (heating element 4) is provided on the heat-insulating material 9. The heat-insulating material 9 can greatly reduce the heat loss in the first sealed chamber 3.

[0101] Preferably, in the present device, in order to obtain the working temperature of the first reactor 1 in real time, a thermocouple 6 is also provided on the first reactor 1, and the end of the thermocouple 6 is exposed in the first sealed chamber 3. The temperature measured by the thermocouple is used to control the flow rate of the fuel mixture, thereby controlling the working temperature of the first reactor 1.

[0102] Preferably, in the present device, Fig.17 As shown, a pressure regulating valve 8 and a mass flow meter 7 are sequentially arranged on the first pipeline 151 connected to the air inlet end of the second gas channel 15 along the gas delivery direction, wherein the air inlet of the first pipeline 151 is named as the first air inlet (i.e. Fig.17 The air inlet ① in the second gas channel 15 is connected to the input end of the fuel channel 211 of the second reactor 2 through the second pipe 152, wherein the end of the second pipe close to the air outlet of the second gas channel is named the first air outlet (i.e. Fig.17 The air outlet ① in the middle), and the other end of the second pipe is named the second fuel inlet (i.e. Fig.17 The fuel inlet ② in the fuel passage is connected to the input end of the fuel passage 211.

[0103] In addition, the output end of the first gas channel 13 of the first reactor outputs the synthesized methane through the third pipeline 131, and the output port of the third pipeline 131 is named the first fuel outlet (i.e. Fig.17 The input end of the first gas channel 13 is connected to the water removal device through the fourth pipe 132, and the end of the fourth pipe 132 close to the first gas channel 13 is named the first fuel inlet (i.e. Fig.17 Fuel import in ①).

[0104] The output end of the fuel channel 211 of the second reactor 2 is connected to the water removal device through the fifth pipe 2111, and the end of the fifth pipe close to the output end is named the second fuel outlet (i.e. Fig.17 The sixth pipe 2611 connected to the air inlet end of the air channel 261 is provided with a pressure regulating valve 8 and a mass flow meter 7 in sequence along the gas delivery mode, and the air inlet of the sixth pipe 2611 is named the second air inlet (i.e. Fig.17 The air outlet of the air channel 261 outputs air through the seventh pipe 2615, and the air outlet of the seventh pipe is named the second air outlet (i.e. Fig.17 Air outlet in the middle ②).

[0105] In the present device, the connection positions of the first / third / fourth / fifth / sixth / seventh pipelines and the first sealed chamber 3 are all sealed.

[0106] Combine the following Fig.17 Give a detailed description of the working process of this application:

[0107] First, the resistance wire is adjusted to make the second reactor 2 reach the temperature required for electrolysis, and then H2 is introduced into the first reactor 1 from the first air inlet, and then enters the fuel channel of the second reactor 2 through the first air outlet and the second fuel inlet, and the anode and the active anode of the second reactor 2 are reduced, and the reduction is completed; then the fuel mixture composed of carbon dioxide, water and hydrogen at 20 to 40°C enters the second gas channel 15 of the first reactor 1 through the first air inlet and the first pipeline 151, and the pressure regulating valve 8 is adjusted to make the fuel mixture within the set flow range. The first reactor 1 heats the fuel mixture and the temperature of the first reactor 1 is reduced; then, the heated fuel mixture flows out from the outlet end of the second gas channel 15, and passes through the first air outlet, the second pipeline 152, the second fuel inlet in sequence. The heated fuel mixture is electrolyzed by the second reactor 2 to produce electrolysis products CO and H2. The electrolysis products, together with the water vapor that does not participate in the reaction and the remaining CO2, enter the dehydration device 5 through the output end of the fuel channel, the second fuel outlet and the fifth pipeline 2111. The dehydration device 5 filters the water vapor and allows the mixture composed of carbon monoxide, hydrogen and carbon dioxide (CO, H2, CO2) to enter the first gas channel 13 of the first reactor 1 through the fourth pipeline 132 and the first fuel inlet. Methane is synthesized in the first reactor 1. Finally, the methane gas is discharged through the third pipeline 131 and the first fuel outlet, and the methane gas is collected in the outside.

[0108] The second device: Fig.18 As shown, the device comprises:

[0109] The first reactor 1 is independently arranged in the second sealed chamber, and the first reactor 1 includes a first gas channel 13 and a third gas channel 16 which are not connected to each other, and the third gas channel 16 is used to circulate the heated air so that the first reactor 1 reaches the methanation temperature; the first reactor 1 is configured to synthesize methane from the mixed gas entering the first gas channel at the methanation temperature;

[0110] The second reactor 2 is independently arranged in the third sealed chamber and a heating element 4 is arranged in the third sealed chamber; the second reactor 2 is a solid oxide fuel cell or a stack structure formed by stacking a plurality of battery units;

[0111] The second reactor 2 includes a fuel channel 211 for introducing fuel gas and an air channel 261 for introducing air, the output end of the fuel channel is connected to the first gas channel 13, and the gas outlet end of the air channel 261 is connected to the third gas channel 16; the second reactor 2 is configured to electrolyze the fuel gas and the air and transport the mixed gas generated by the electrolysis in the fuel channel 211 to the first gas channel;

[0112] The air channel 261 is used to heat the air flowing therein and output the heated air to the third gas channel 16 .

[0113] In the device, the first reactor 1 and the second reactor 2 are respectively arranged in different sealed chambers, wherein the inner wall of the second sealed chamber is provided with a heat preservation material 9, and the inner wall of the third sealed chamber is provided with a heat preservation material 9 and a heating element 4 in sequence from the outside to the inside. For example, the heating element can be a resistance wire.

[0114] In this device, the first reactor 1 includes a first gas channel 13 and a third gas channel 16. Specifically, Figure 7-9 As shown, the first reactor 1 includes a plurality of synthetic methane units stacked in sequence along the vertical direction; the synthetic methane unit includes a support body 11 and a flow channel sheet 12, and a plurality of first gas channels 13 are arranged inside the support body 11; the flow channel sheet 12 is sealed and stacked on the surface of the support body 11, and a plurality of third gas channels 16 are formed on the flow channel sheet 12.

[0115] For example, the material of the support 11 is Ni-YSZ, wherein YSZ is 2 mol%-10 mol% Y2O3-stabilized ZrO3; the mass percentage of Ni is 40wt%-60wt%, and the mass percentage of YSZ is 40wt%-60wt%;

[0116] The porosity of the support is 50 to 80%;

[0117] A dense insulating layer 14 is sealed between the support body 11 and the flow channel sheet 12 , and the dense insulating layer 14 covers the outside of the support body 11 ; the first gas channel 13 and the third gas channel 16 are arranged perpendicularly.

[0118] In this device, since there is no heating element in the second sealed chamber where the first reactor 1 is located, the first reactor 1 is not heated by an additional power supply. Therefore, in order to make the temperature of the first reactor 1 reach the methanation temperature, the high-temperature air exhaust gas in the second reactor 2 is used in this device to heat the first reactor 1 to the methanation temperature, saving heating energy and utilizing the waste heat of the air exhaust gas.

[0119] Specifically, during operation, since the third sealed chamber is provided with a heating element 4, the second reactor 2 therein is heated and maintained at an operating temperature (600-900°C, preferably about 750°C). First, H2 is introduced into the fuel channel 211 and air is introduced into the air channel 261, and H2 reduces the battery (specifically the anode and active anode in the battery) in the second reactor 2. At the same time, the air heated by the second reactor 2 is introduced into the third gas channel 16 of the first reactor 1 through the gas outlet end of the air channel 261, and the first reactor 1 is heated to the temperature required for synthesizing methane (200-600°C).

[0120] Among them, by real-time detection of the voltage of the second reactor 2, it is determined whether the battery in the second reactor is completely reduced. For example, when the detected voltage of the second reactor remains unchanged, it means that the battery in the second reactor is completely reduced (generally, after 2 to 4 hours of H2 being introduced, the voltage of the second reactor remains unchanged).

[0121] After the reduction is completed, the fuel gas (mixed by carbon dioxide, water vapor and hydrogen) is introduced into the fuel channel 211, and the second reactor 2 electrolyzes the fuel gas and air to generate carbon monoxide CO and hydrogen H2 on the fuel electrode side and oxygen O2 on the air electrode side, and O2 is discharged to the third gas channel 16 of the first reactor 1 through the output end of the air channel 261, and then discharged to the outside from the gas outlet end of the third gas channel 16. Among them, CO, H2, water vapor that does not participate in the reaction, and CO2 that does not react completely are output from the output end of the fuel channel 211.

[0122] In the present device, the output end of the fuel channel 211 is connected to the input end of the first gas channel 13 through the dehydration device 5. Therefore, the mixed gas composed of CO, H2, CO2 and water vapor output from the output end of the fuel channel 211 first passes through the dehydration device 5, and the water vapor in the mixed gas is filtered by the dehydration device 5, and then the mixed gas composed of CO, H2 and CO2 is transported to the first gas channel 13 of the first reactor 1, and the first reactor 1 synthesizes methane from the mixed gas, and then the synthesized methane gas is discharged from the output end (gas outlet end) of the first gas channel 13 to the outside, and the methane gas is collected by the outside.

[0123] In the device, the waste heat of the air tail gas of the second reactor 2 can be effectively utilized to heat the first reactor 1 to the methanation temperature without the need to additionally heat the first reactor 1, thus saving energy consumption.

[0124] Preferably, in the present device, the fuel gas flowing in the fuel channel is a mixture of carbon dioxide, water vapor and hydrogen, and the flow ratio of the three is 1 to 3:1 to 3:1; preferably 2:2:1 or 3:1:1 or 1:3:1.

[0125] The air flow rate in the air channel is 3 to 20 L / min. The air flow rate in the air channel is controlled and adjusted to ensure that the temperature of the first reactor reaches the required methanation temperature while ensuring that the methanation temperature is constant.

[0126] In the present device, the eighth pipe 2612 connected to the air inlet end of the air channel 261 is provided with a pressure regulating valve 8 and a mass flow meter 7 in sequence along the gas delivery direction; and the air inlet of the eighth pipe 2612 is named the fourth air inlet (i.e. Fig.18 The air inlet ④ in the air inlet is provided, and an air pump 2613 is also provided at the fourth air inlet. The air outlet end of the air channel 261 is connected to the air inlet end of the third gas channel 16 of the first reactor through the ninth pipeline 2614; and the end of the ninth pipeline 2614 close to the second reactor is named the fourth air outlet (i.e. Fig.18 The other end of the ninth pipe is named the third air inlet (i.e. Fig.18 The third air inlet is connected to the air inlet end of the third gas channel 16 of the first reactor 1. The ninth pipeline 2614 exposed outside the sealed chamber is wrapped with a heat-insulating material.

[0127] The output end of the fuel channel 211 of the second reactor 2 is connected to the water removal device through the eleventh pipeline 2112, and the end of the eleventh pipeline close to the fuel channel is named the fourth fuel outlet ( Fig.18 Fuel outlet in ④).

[0128] A pressure regulating valve 8 and a mass flow meter 7 are provided in sequence on the fourteenth pipeline 2113 connected to the input end of the fuel channel 211 along the gas delivery direction; and the inlet of the fourteenth pipeline is named the fourth fuel inlet ( Fig.18 The fuel inlet ④) in the middle, and the fourth fuel inlet is provided with a gas cylinder.

[0129] The air outlet of the third gas channel 16 of the first reactor 1 is discharged to the outside through the tenth pipeline 161, wherein the air outlet of the tenth pipeline is named as the third air outlet (i.e. Fig.18 Air outlet in the middle ③).

[0130] The gas outlet (output end) of the first gas channel 13 of the first reactor discharges the methane gas synthesized therein through the thirteenth pipeline 133, and the outlet of the thirteenth pipeline is named the third fuel outlet ( Fig.18 Fuel outlet in ③).

[0131] The dehydration device is connected to the gas inlet end (input end) of the first gas channel 13 of the first reactor 1 through the twelfth pipeline 134, wherein the end of the twelfth pipeline close to the first reactor 1 is named the third fuel inlet ( Fig.18The fuel inlet in ③); the twelfth pipeline 134 is also provided with a branch pipeline 135 and a pressure regulating valve on the branch pipeline. The gas in the twelfth pipeline is detected through the branch pipeline to regularly analyze the hydrogen-carbon ratio to maintain the normal operation of the device.

[0132] Combine the following Fig.18 The working process of this device is described in detail:

[0133] During operation, the resistance wire in the third sealed chamber is heated to maintain the second reactor 2 at the operating temperature. First, hydrogen is introduced into the fuel channel 211 through the fourth fuel inlet and the fourteenth pipeline 2113, and at the same time, air enters the air channel 261 through the air pump, the fourth air inlet, and the eighth pipeline 2612. H2 reduces the battery of the second reactor 2. At the same time, the air in the air channel 261 is heated and the heated air enters the third gas channel 16 of the first reactor 1 through the fourth air outlet, the ninth pipeline, and the third air inlet in turn, and heats the first reactor 1 to the methanogenic temperature (200-600°C). After detecting that the voltage of the second reactor 2 remains unchanged, the fuel gas mixed with carbon dioxide, water vapor, and hydrogen enters the fuel channel 2 through the fourteenth pipeline 2113. In 11, the second reactor 2 electrolyzes the fuel gas and air to produce CO, H2, and O2, wherein O2 is generated in the air channel 261 and discharged to the outside from the fourth air outlet, the third air inlet, the third gas channel, and the third air outlet. At the same time, CO, H2, water vapor that does not participate in the reaction, and CO2 that does not react completely in the fuel channel are discharged from the fourth fuel outlet to the dehydration device, and the water vapor is filtered by the dehydration device. Then, the mixed gas of CO, H2 and CO2 enters the first gas channel 13 through the twelfth pipeline 134 and the third fuel inlet. The first reactor 1 synthesizes methane from the mixed gas, and finally the methane is transported to the outside from the thirteenth pipeline 133 and the third fuel outlet, and then the methane is collected.

[0134] In a second aspect, the present disclosure also provides a carbon dioxide direct methanation system, including a power supply device and the above-mentioned carbon dioxide direct methanation device. The system with the device can also achieve the carbon reduction target and can be converted into methane fuel with high efficiency.

[0135] The present application is further described in detail below with reference to specific embodiments:

[0136] Example 1

[0137] like Figure 10-13 As shown, the first reactor 1 is assembled by placing three Figure 2The synthetic methane units shown are stacked and assembled, and are sealed on all sides with sealing materials to prevent gas leakage. The support material in the synthetic methane unit is Ni-YSZ, the mass percentage of Ni is 54wt%, the mass percentage of YSZ is 46wt%, and YSZ is 3mol% Y2O3-stabilized ZrO3; the porosity of the support is 60%.

[0138] Second reactor 2 assembly: 3 battery cells are connected in series to form a battery stack structure. The battery cells of the battery stack structure include an anode of NiO-3YSZ, an active anode of NiO-8YSZ, an electrolyte of 8YSZ, a barrier layer of GDC, and a cathode of LSCF / GDC.

[0139] Place the first reactor 1 in the second sealed chamber, and the second reactor 2 in the third sealed chamber. Fig.18 The carbon dioxide direct methanation device has been assembled.

[0140] The resistance wire is heated to make the temperature of the second reactor reach 750°C, H2 is introduced into the fuel channel 211 from the fourth fuel inlet, and air is introduced into the air channel 261 from the fourth air inlet. The anode and active anode of the second reactor 2 are reduced to Ni-YSZ until the open circuit voltage OCV of the second reactor 2 is detected to remain stable at 1.0-1.23V; the air in the second reactor 2 is heated to about 650°C, and the first reactor is heated to 500°C by adjusting the air flow rate in the air channel (9L / min).

[0141] After the reduction of the second reactor 2 is completed, a fuel gas mixed with 1 SLM (L / min) (40 vol%) of carbon dioxide, 1 SLM (40 vol%) of water vapor and 0.5 SLM (20 vol%) of hydrogen is introduced into the fuel channel to start electrolysis, the electrolysis voltage is 3.6 V, the electrolysis current is 40 A, the generated carbon monoxide, hydrogen and incompletely reacted CO2 (hydrogen-carbon ratio H / C is 3) are discharged from the fourth fuel outlet, and enter the first reactor 1 after passing through the water removal device, and the methane synthesis rate is 95%. The oxygen generated by electrolysis is discharged through the fourth air outlet, the third air inlet and the third air outlet, the measured flow rate is 408 sccm, and the oxygen purity is 99%.

[0142] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps recorded in this disclosure can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solutions disclosed in this disclosure can be achieved, and this document does not limit this.

[0143] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0144] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A carbon dioxide direct methanation device, characterized in that: include: The first reactor comprises a first gas channel and a second gas channel which are not interconnected, wherein the first reactor is configured to synthesize methane from the mixed gas entering the first gas channel and heat the low-temperature fuel mixed gas entering the second gas channel and transport the mixed gas to the second reactor; The second reactor is disposed together with the first reactor in the first sealed chamber and the two are disposed far away from each other, and a heating element is disposed in the first sealed chamber near the second reactor; the second reactor is a solid oxide fuel cell or a stack structure formed by stacking a plurality of battery units; The second reactor includes a fuel channel and an air channel; the input end of the fuel channel is connected to the second gas channel, and the output end is connected to the first gas channel; the second reactor is configured to electrolyze the heated fuel mixture and transport the mixture generated by electrolysis in the fuel channel to the first gas channel.

2. The carbon dioxide direct methanation device according to claim 1, characterized in that: The output end of the fuel channel is connected to the first gas channel through a water removal device; The heating element is a resistance wire.

3. The carbon dioxide direct methanation device according to claim 1, characterized in that: The first reactor comprises a plurality of synthetic methane units stacked in sequence in a vertical direction; The synthetic methane unit comprises a support body and a flow channel sheet, wherein a plurality of the first gas channels are arranged inside the support body; the flow channel sheet is sealed and stacked on the surface of the support body, and a plurality of the second gas channels are formed on the flow channel sheet.

4. The carbon dioxide direct methanation device according to claim 3, characterized in that: The material of the support is Ni-YSZ, wherein YSZ is 2mol%-10mol% Y2O3-stabilized ZrO3; the mass percentage of Ni is 40wt%-60wt%, and the mass percentage of YSZ is 40wt%-60wt%; The porosity of the support is 50-80%; A dense insulating layer is also provided between the support body and the flow channel sheet in a sealed manner, and the dense insulating layer is coated on the outside of the support body; The first gas channel is arranged perpendicular to the second gas channel; The material of the dense insulating layer is YSZ, GDC, and the thermal expansion coefficient is 9.0×10 -6 ~20.0×10 -6 / ℃ a mixture of one or more sealing glass materials.

5. The carbon dioxide direct methanation device according to claim 1, characterized in that: The second reactor comprises an anode, an active anode, an electrolyte, a barrier layer and a cathode. The anode is NiO-3YSZ, the active anode is NiO-8YSZ, the electrolyte is 8YSZ, the barrier layer is GDC, and the cathode is LSCF / GDC.

6. The carbon dioxide direct methanation device according to claim 1, characterized in that: The temperature of the low-temperature fuel mixed gas before heating is 20-40°C; The fuel mixed gas is a mixture of carbon dioxide, water and hydrogen, and the flow ratio of the three is 1-3:1-3:

1.

7. The carbon dioxide direct methanation device according to any one of claims 1 to 6, characterized in that: On the pipeline connected to the air inlet end of the second gas channel, a pressure regulating valve and a mass flow meter are sequentially provided along the gas delivery direction; on the pipeline connected to the air inlet end of the air channel, a pressure regulating valve and a mass flow meter are sequentially provided along the gas delivery direction; The fuel mixture is a mixture of carbon dioxide, water and hydrogen, and the flow ratio of the three is 2:2:1 or 3:1:1 or 1:3:

1.

8. A carbon dioxide direct methanation device, characterized in that: include: A first reactor is independently arranged in the second sealed chamber, the first reactor comprises a first gas channel and a third gas channel which are not connected to each other, the third gas channel is used to circulate heated air so that the first reactor reaches a methanation temperature; the first reactor is configured to synthesize methane from the mixed gas entering the first gas channel at the methanation temperature; A second reactor is independently arranged in the third sealed chamber and a heating element is arranged in the third sealed chamber; the second reactor is a solid oxide fuel cell or a stack structure formed by stacking a plurality of battery units; The second reactor includes a fuel channel and an air channel, the output end of the fuel channel is connected to the first gas channel, and the air outlet end of the air channel is connected to the third gas channel; wherein the air channel is used to heat the air flowing therein and output the heated air to the third gas channel; the second reactor is configured to electrolyze the fuel gas and transport the mixed gas generated by the electrolysis in the fuel channel to the first gas channel.

9. The carbon dioxide direct methanation device according to claim 8, characterized in that: The output end of the fuel channel is connected to the input end of the first gas channel through a water removal device; The heating element is a resistance wire.

10. The carbon dioxide direct methanation device according to claim 8, characterized in that: The first reactor comprises a plurality of synthetic methane units stacked in sequence in a vertical direction; The synthetic methane unit comprises a support body and a flow channel sheet, wherein a plurality of the first gas channels are arranged inside the support body; the flow channel sheet is sealed and stacked on the surface of the support body, and a plurality of the third gas channels are formed on the flow channel sheet.

11. The carbon dioxide direct methanation device according to claim 10, characterized in that: The material of the support is Ni-YSZ, wherein YSZ is 2mol%-10mol% Y2O3-stabilized ZrO3; the mass percentage of Ni is 40wt%-60wt%, and the mass percentage of YSZ is 40wt%-60wt%; The porosity of the support is 50-80%; A dense insulating layer is also provided between the support body and the flow channel sheet in a sealed manner, and the dense insulating layer is coated on the outside of the support body; The first gas channel and the third gas channel are arranged perpendicularly; The material of the dense insulating layer is YSZ, GDC, and the thermal expansion coefficient is 9.0×10 -6 ~20.0×10 -6 / ℃ a mixture of one or more sealing glass materials.

12. The carbon dioxide direct methanation device according to claim 8, characterized in that: The fuel gas flowing in the fuel channel is a mixture of carbon dioxide, water vapor and hydrogen, and the flow ratio of the three is 1 to 3:1 to 3:1; The air flow rate in the air channel is 3 to 20 L / min.

13. The carbon dioxide direct methanation device according to claim 8, characterized in that: The second reactor comprises an anode, an active anode, an electrolyte, a barrier layer and a cathode. The anode is NiO-3YSZ, the active anode is NiO-8YSZ, the electrolyte is 8YSZ, the barrier layer is GDC, and the cathode is LSCF / GDC.

14. The carbon dioxide direct methanation device according to any one of claims 8 to 13, characterized in that: A pressure regulating valve and a mass flow meter are sequentially provided on the pipeline connected to the air inlet end of the air channel along the gas delivery direction; a pressure regulating valve and a mass flow meter are sequentially provided on the pipeline connected to the input end of the fuel channel along the gas delivery direction; The fuel gas flowing in the fuel channel is a mixture of carbon dioxide, water vapor and hydrogen, and the flow ratio of the three is 2:2:1 or 3:1:1 or 1:3:

1.

15. A carbon dioxide direct methanation system, comprising a power supply device, characterized in that: It also includes the carbon dioxide direct methanation device according to any one of claims 1-14.

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