Methane generation system

Abstract

A methane generation system according to the present disclosure is provided with: a water supply path through which water or water vapor is supplied; a carbon dioxide supply path for supplying carbon dioxide; a power supply path for supplying power; an SOEC co-electrolysis device in which the water supply path, the carbon dioxide supply path, and the power supply path are connected; a methane reactor; a connection path that connects the SOEC co-electrolysis device and the methane reactor; and a first heat exchange unit that exchanges heat between the SOEC co-electrolysis device and the methane reactor.

Description

Technical Field

[0001] The present disclosure relates to methane generation systems. Background Art

[0003] Conventionally, a methanation system is known in which, when methane is produced using carbon dioxide, water, and electricity, the conversion efficiency of water to methane is improved by reusing the methane reaction heat of a methanation reaction section in a steam generation section (Patent Document 1).

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2022-22978 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In a methanation system using a solid oxide electrolysis cell (SOEC) co-electrolysis device that simultaneously electrolyzes carbon dioxide and water vapor at a high temperature of more than 500°C (co-electrolysis), in the process of generating methane from water, electricity and carbon dioxide in the SOEC co-electrolysis device, the heat of the methane reaction in the methanation reaction unit is insufficient, and there is a possibility that the methane conversion efficiency will decrease or the methane generation amount will become unstable.

[0009] The present disclosure is made under such background, and its purpose is to thermally connect the SOEC co-electrolysis device with the methanation reaction unit (methane reactor), effectively remove the reaction heat from the methane reactor through mutual heat exchange, and reuse it in the SOEC co-electrolysis device, thereby improving the methane conversion efficiency and stabilizing the methane production.

[0010] Solutions to Solve Problems

[0011] One mode of the methane generation system involved in the present disclosure comprises: a water supply path, which supplies water or water vapor; a carbon dioxide supply path, which supplies carbon dioxide; an electric power supply path, which supplies electric power; a SOEC co-electrolysis device, which connects the above-mentioned water supply path, the above-mentioned carbon dioxide supply path and the above-mentioned electric power supply path; a methane reactor; a connecting path, which connects the above-mentioned SOEC co-electrolysis device with the above-mentioned methane reactor; and a first heat exchange part, which performs heat exchange between the above-mentioned SOEC co-electrolysis device and the above-mentioned methane reactor.

[0012] One method of the methane generation system involved in the present disclosure comprises: a water supply path, which supplies water or water vapor; a carbon dioxide supply path, which supplies carbon dioxide; an electric power supply path, which supplies electric power; a SOEC co-electrolysis device, which is connected to the above-mentioned water supply path, the above-mentioned carbon dioxide supply path and the above-mentioned electric power supply path; a methane reactor; a connecting path, which connects the above-mentioned SOEC co-electrolysis device with the above-mentioned methane reactor; a first heat exchange part, which performs heat exchange between the above-mentioned SOEC co-electrolysis device and the above-mentioned methane reactor; and a preliminary heat exchange part, which utilizes the reaction heat of the above-mentioned methane reactor to heat the above-mentioned water or water vapor supplied from the above-mentioned water supply path to the above-mentioned SOEC co-electrolysis device.

[0013] Effects of the Invention

[0014] According to the present disclosure, methane conversion efficiency can be improved by reusing methane reaction heat by a SOEC co-electrolysis device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram showing the front view of the methane production system according to the first embodiment.

[0016] Figure 2 This is a schematic diagram showing the front view of the methane production system according to the second embodiment.

[0017] Figure 3 This is a schematic diagram showing the front view of the methane production system according to the third embodiment.

[0018] Figure 4 This is a schematic diagram showing the front view of the methane production system according to the fourth embodiment.

[0019] Figure 5 This is a schematic diagram showing the front view of the methane production system according to the fifth embodiment.

[0020] Figure 6 This is a schematic diagram showing the front view of the methane production system according to the sixth embodiment.

[0021] Figure 7 This is a schematic diagram showing the front view of the methane production system according to the seventh embodiment.

[0022] Figure 8 This is a schematic diagram showing the front view of the methane production system according to the eighth embodiment.

[0023] Fig. 9 This is a schematic diagram showing the front view of the methane production system according to the ninth embodiment.

[0024] Fig.9A This is a schematic diagram showing the front view of the methane production system according to Embodiment 9A.

[0025] Fig.10 This is a schematic diagram showing the front view of the methane production system according to the tenth embodiment.

[0026] Fig.11 This is a schematic diagram showing the front view of the methane production system according to the eleventh embodiment.

[0027] Fig.12 This is a schematic diagram showing the front view of the methane production system according to the twelfth embodiment.

[0028] Fig.13 This is a schematic diagram showing the front view of the methane production system according to the thirteenth embodiment.

[0029] Fig.14 This is a schematic diagram showing the front view of the methane production system according to the fourteenth embodiment.

[0030] Fig.15 This is a schematic diagram showing the front view of the methane production system according to the fifteenth embodiment.

[0031] Fig.16 This is a schematic diagram showing the front view of the methane production system according to the sixteenth embodiment.

[0032] Fig.17 This is a schematic diagram showing the front view of the methane production system according to the seventeenth embodiment.

[0033] Fig.18 This is a schematic diagram showing the front view of the methane production system according to the eighteenth embodiment.

[0034] Fig.19 This is a schematic diagram showing the front view of the methane production system according to the nineteenth embodiment.

[0035] Fig. 20 This is a schematic diagram showing the front view of the methane production system according to the twentieth embodiment.

[0036] Fig.21 This is a schematic diagram showing the front view of the methane production system according to Embodiment 21.

[0037] Fig. 22 This is a schematic diagram showing the front view of the methane production system involved in Embodiment 22.

[0038] Fig.23 This is a schematic diagram showing the front view of the methane production system according to the twenty-third embodiment.

[0039] Fig.24 This is a schematic diagram showing the front view of the methane production system involved in Embodiment 24.

[0040] Fig.25 This is a schematic diagram showing the front view of the methane production system involved in Embodiment 25.

[0041] Fig.26 This is a schematic diagram showing the front view of the methane production system involved in Embodiment 26. DETAILED DESCRIPTION [Implementation Method 1]

[0042] Below, refer to Figure 1 A methane generation system 50 according to Embodiment 1 of the present disclosure will be described.

[0043] The methane generation system 50 includes: a SOEC co-electrolysis device 10; a methane reactor 11; and a first heat exchange unit 20 thermally connected to the SOEC co-electrolysis device 10 and the methane reactor 11. Figure 1 In the example, the SOEC co-electrolysis device 10, the first heat exchange unit 20 and the methane reactor 11 are arranged in a horizontal direction. In the SOEC co-electrolysis device 10, a power supply path 1 for supplying power, a water supply path (H 2 O) or water vapor and the water supply path 2 for supplying carbon dioxide (CO 2 ) of the carbon dioxide supply path 3. The water or water vapor and carbon dioxide supplied from the water supply path 2 and the carbon dioxide supply path 3 to the SOEC co-electrolysis device 10 are simultaneously electrolyzed in the SOEC co-electrolysis device 10 and converted into hydrogen and carbon monoxide. The water or water vapor flowing in the water supply path 2 and the carbon dioxide flowing in the carbon dioxide supply path 3 obtain kinetic energy from fluid machinery such as a pump or blower not shown in the figure and move to the SOEC co-electrolysis device 10.

[0044] The hydrogen and carbon monoxide converted by electrolysis in the SOEC co-electrolyzer 10 are supplied to the methane reactor 11 via the connection path 4 connecting the SOEC co-electrolyzer 10 and the methane reactor 11 .

[0045] The hydrogen and carbon monoxide supplied to the methane reactor 11 are converted into methane (CH 4 ) and water, and methane is supplied to the external gas infrastructure 30 via the gas path 6.

[0046] Here, since the reaction carried out in the SOEC co-electrolysis device 10 is an endothermic reaction, heat is required for the reaction. On the other hand, the reaction carried out in the methane reactor 11 is an exothermic reaction, and thus generates heat. Therefore, the heat generated by the exothermic reaction of the methane reactor 11 and the heat required by the SOEC co-electrolysis device 10 are heat-exchanged via the first heat exchange unit 20. In this way, the heat generated in the methane reactor 11 is reused by the SOEC co-electrolysis device 10, and the heat generated in the methane reactor 11 can be effectively removed. In addition, the heat required by the SOEC co-electrolysis device 10 can be supplied with the heat generated in the methane reactor 11, so that the methane conversion efficiency can be improved and the methane generation amount can be stabilized.

[0047] Here, the power supplied to the SOEC co-electrolysis device 10 is preferably renewable energy such as wind power generation and solar power generation. Alternatively, it can also be power generated from a solid oxide fuel cell (SOFC: Solid Oxide Fuel Cell). SOFC is a device that uses hydrogen as fuel, extracts electrons from oxygen taken from the air, and the oxygen (oxygen ions) from which the electrons are extracted reacts with hydrogen to generate water, and in this process, current is extracted to the outside. In addition, the power supplied to the SOEC co-electrolysis device 10 may not be renewable energy or power from SOFC.

[0048] The carbon dioxide supplied to the SOEC co-electrolysis device 10 may be supplied from, for example, carbon dioxide exhausted from the SOFC, carbon dioxide recovered from the atmosphere by DAC (Direct Air Capture), or other carbon dioxide supply sources.

[0049] Here, the structure of the first heat exchange part 20 is not particularly limited, and a known heat exchanger can be used as long as it can perform heat exchange between the SOEC co-electrolysis device 10 and the methane reactor 11. For example, a known heat exchanger such as a multi-tube heat exchanger, a plate heat exchanger, a coil heat exchanger, a double tube, a spiral heat exchanger, etc. can be used. [Implementation Method 2]

[0050] Below, refer to Figure 2 The methane generation system 51 according to the second embodiment of the present disclosure will be described. Figure 1 The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted, and only components different from those in the first embodiment are described.

[0051] The methane generation system 51 includes a heat-fused flow path 5 that supplies at least a portion of water or water vapor generated and released in the methane reactor 11 to the SOEC co-electrolysis device 10 .

[0052] According to such a configuration, at least a portion of the high-temperature water or steam generated in the methane reactor 11 is supplied to the SOEC co-electrolysis device 10 via the heat-melting flow path 5. Therefore, the heat of the high-temperature water or steam can be reused by the SOEC co-electrolysis device 10. Thus, since the heat required by the SOEC co-electrolysis device 10 can be supplied by the heat generated in the methane reactor 11, the methane conversion efficiency can be improved and the methane generation amount can be stabilized. [Implementation method 3]

[0053] Below, refer to Figure 3 The methane generation system 52 according to the third embodiment of the present disclosure will be described. Figure 2 The same configurations as those in the second embodiment are denoted by the same reference numerals and description thereof is omitted, and only configurations different from those in the second embodiment are described.

[0054] The methane generation system 52 includes a second heat exchange unit 21 in the heat fusion flow path 5 for performing heat exchange with external exhaust heat.

[0055] In addition to the heat generated in the methane reactor 11, the water or steam flowing in the hot melt flow path 5 can obtain more heat by exchanging heat with the external exhaust heat through the second heat exchange part 21. Therefore, since the heat required by the SOEC co-electrolysis device 10 can be supplied with the heat generated in the methane reactor 11 and the external exhaust heat, the methane conversion efficiency can be improved and the methane generation amount can be stabilized.

[0056] Here, the external exhaust heat includes, in order from low-temperature exhaust heat to high-temperature exhaust heat, ventilation exhaust heat, air-conditioning exhaust heat, hot water supply exhaust heat, water heater exhaust heat, and SOFC fuel cell exhaust heat.

[0057] The ventilation exhaust heat is, for example, exhaust heat generated when air accumulated in a building or an office building constructed on a site such as a factory where the methane generation system 52 is installed is exhausted to the outside.

[0058] The air-conditioning exhaust heat is, for example, exhaust heat from an air conditioner installed in a building or an office building constructed on a site such as a factory where the methane generation system 52 is installed.

[0059] The hot water exhaust heat is, for example, exhaust heat from a water heater installed in a building or an office building constructed on the site of a factory or the like where the methane generation system 52 is installed.

[0060] The water heater exhaust heat is, for example, exhaust heat from a water heater installed in a building or an office building constructed on the site of a factory or the like where the methane generation system 52 is installed.

[0061] SOFC fuel cell exhaust heat is exhaust heat generated when SOFC is operated. Since the operating temperature of SOFC is as high as about 1000°C, high-temperature exhaust heat can be extracted.

[0062] The SOEC co-electrolysis device 10 and the methane reactor 11 may also be physically integrated. Here, the so-called physically integrated means that the SOEC co-electrolysis device 10 and the methane reactor 11 are formed of the same component as one component. Alternatively, the SOEC co-electrolysis device 10 and the methane reactor 11 formed of different components may be integrated by welding. Alternatively, the SOEC co-electrolysis device 10 and the methane reactor 11 formed of different components may be integrated via fastening components such as bolts and nuts. [Implementation Method 4]

[0063] Below, refer to Figure 4 The methane generation system 53 according to the fourth embodiment of the present disclosure will be described. Figure 3 The same configurations as those in the third embodiment are denoted by the same reference numerals and description thereof is omitted, and only configurations different from those in the third embodiment are described.

[0064] In the methane generation system 53, the SOEC co-electrolysis device 10 is provided at a position higher than the methane reactor 11. That is, the SOEC co-electrolysis device 10 is provided on the upper side of the methane reactor 11 so that Figure 3 The methane generation system 52 shown rotates clockwise. In this case, the SOEC co-electrolysis device 10, the first heat exchange unit 20 and the methane reactor 11 are arranged in the vertical direction. In this way, the configuration in which the SOEC co-electrolysis device 10 is arranged on the upper side of the methane reactor 11 is sometimes referred to as a configuration arranged in a vertical type. In addition, the SOEC co-electrolysis device 10 may also be arranged at a position higher than the methane reactor 11 so as to directly face the methane reactor 11 without the first heat exchange unit 20 therebetween.

[0065] In such a methane generation system 53, the SOEC co-electrolysis device 10 is provided at a higher position than the methane reactor 11. Therefore, it is possible to increase the temperature difference between the fluids existing near the heat transfer surfaces of the SOEC co-electrolysis device 10 and the methane reactor 11. Thus, it is possible to improve the heat exchange performance between the SOEC co-electrolysis device 10 and the methane reactor 11, thereby improving the methane conversion efficiency. [Implementation method 5]

[0066] Below, refer to Figure 5 A methane generation system 54 according to Embodiment 5 of the present disclosure will be described. Figure 3The same configurations as those in the third embodiment are denoted by the same reference numerals and description thereof is omitted, and only configurations different from those in the third embodiment are described.

[0067] The methane generation system 54 includes a first heater 22 in addition to the second heat exchange unit 21 in the heat fusion flow path 5. Figure 5 In the example, the first heater 22 is provided on the downstream side of the second heat exchange portion 21 in the flow direction of water or water vapor flowing through the heat fusion flow path 5 .

[0068] The water or water vapor flowing in the hot melt flow path 5 can obtain the heat generated in the methane reactor 11, the heat obtained by heat exchange with the external exhaust heat through the second heat exchange part 21, and the heat obtained by the first heater 22. Therefore, the heat generated in the methane reactor 11, the external exhaust heat and the heat obtained by the first heater 22 can be used to supply the heat required by the SOEC co-electrolysis device 10. As a result, the methane conversion efficiency can be improved and the methane generation amount can be stabilized. [Implementation Method 6]

[0069] Below, refer to Figure 6 The methane generation system 55 according to the sixth embodiment of the present disclosure will be described. Figure 5 The same configurations as those in the fifth embodiment are denoted by the same reference numerals and description thereof is omitted, and only configurations different from those in the fifth embodiment are described.

[0070] The methane generation system 55 has the following configuration: a SOEC co-electrolysis device 10 is installed on the upper side of a methane reactor 11. Figure 5 The methane generation system 54 of the fifth embodiment shown is arranged in a vertical type. Therefore, since the SOEC co-electrolysis device 10 is arranged at a higher position than the methane reactor 11, the temperature difference between the fluids existing near the heat transfer surfaces of the SOEC co-electrolysis device 10 and the methane reactor 11 can be increased. Figure 5 In addition to the effects obtained by the methane generation system 54 of the fifth embodiment shown, the heat exchange performance between the SOEC co-electrolysis device 10 and the methane reactor 11 can be improved, so the methane conversion efficiency can be improved and the methane generation amount can be stabilized. [Implementation method 7]

[0071] Below, refer to Figure 7 The methane generation system 56 according to the seventh embodiment of the present disclosure will be described. Figure 5 The same configurations as those in the fifth embodiment are denoted by the same reference numerals and description thereof is omitted, and only configurations different from those in the fifth embodiment are described.

[0072] The methane generation system 56 has at least one of the following parts for heating water or water vapor flowing through the heat fusion flow path 5 in the second heat exchange part 21: the third heat exchange part 23 for heat exchange with external ventilation exhaust heat; the fourth heat exchange part 24 for heat exchange with external air conditioning exhaust heat; the fifth heat exchange part 25 for heat exchange with external hot water supply exhaust heat; the sixth heat exchange part 26 for heat exchange with external water heater exhaust heat; and the seventh heat exchange part 27 for heat exchange with external SOFC fuel cell exhaust heat. Here, with respect to the flow direction of water or water vapor flowing through the heat fusion flow path 5, the lower the temperature of the heat exchange part, the more upstream it is arranged.

[0073] Therefore, the third heat exchange part 23 with the lowest temperature is provided at the most upstream relative to the flow direction of water or water vapor flowing in the heat fusion flow path 5, and the seventh heat exchange part 27 with the highest temperature is provided at the most downstream relative to the flow direction of the fluid flowing in the heat fusion flow path 5. Between the third heat exchange part 23 and the seventh heat exchange part 27, the fourth heat exchange part 24, the fifth heat exchange part 25, and the sixth heat exchange part 26 are provided from the upstream side relative to the flow direction of water or water vapor flowing in the heat fusion flow path 5.

[0074] In such a methane generation system 56, water or water vapor flowing in the heat fusion flow path 5 is heat exchanged sequentially from the heat exchange part with a lower temperature to the heat exchange part with a higher temperature. Therefore, even a low-temperature external heat source can be effectively used as a heating source for the water or water vapor flowing in the heat fusion flow path 5.

[0075] exist Figure 7 In the example of , the third heat exchange section 23, the fourth heat exchange section 24, the fifth heat exchange section 25, the sixth heat exchange section 26, and the seventh heat exchange section 27 are all provided, but it is sufficient to provide at least one of them. When the third heat exchange section 23, the fourth heat exchange section 24, the fifth heat exchange section 25, the sixth heat exchange section 26, and the seventh heat exchange section 27 are all provided, the effect of increasing the heat of water or water vapor supplied to the SOEC co-electrolysis device 10 is maximized. [Embodiment 8]

[0076] Below, refer to Figure 8 The methane generation system 57 according to the eighth embodiment of the present disclosure will be described. Figure 7 The same configurations as in the seventh embodiment are denoted by the same reference numerals and descriptions thereof are omitted, and only configurations different from those in the seventh embodiment are described.

[0077] The methane generation system 57 has the following configuration: a SOEC co-electrolysis device 10 is installed on the upper side of a methane reactor 11. Figure 7 The methane generation system 56 of the seventh embodiment shown is arranged in a vertical type. Therefore, the SOEC co-electrolysis device 10 is arranged at a higher position than the methane reactor 11, so that the temperature difference between the fluids existing near the heat transfer surfaces of the SOEC co-electrolysis device 10 and the methane reactor 11 can be increased. Figure 7 In addition to the effects obtained by the methane generation system 56 of the seventh embodiment shown, the heat exchange performance between the SOEC co-electrolysis device 10 and the methane reactor 11 can be improved, so the methane conversion efficiency can be improved and the methane generation amount can be stabilized. [Implementation Method 9]

[0078] Below, refer to Fig. 9 The methane generation system 58 according to the ninth embodiment of the present disclosure will be described. Figure 7 The same configurations as in the seventh embodiment are denoted by the same reference numerals and descriptions thereof are omitted, and only configurations different from those in the seventh embodiment are described.

[0079] Methane generation system 58 Figure 7 The methane production system 56 of the seventh embodiment shown includes the first preliminary heat exchange section 28 for heating the water or steam flowing through the water supply path 2 using the reaction heat of the methane reactor 11 .

[0080] In such a methane generation system 58, the heat of water or steam supplied to the SOEC co-electrolysis device 10 is increased by the first preliminary heat exchanger 28, thereby promoting electrolysis in the SOEC co-electrolysis device 10. Furthermore, the heat generated from the methane reactor 11 is removed by the first preliminary heat exchanger 28, and the methane conversion efficiency can be improved. [Implementation Method 9A]

[0081] Fig.9A The configuration of a methane generation system 58A according to Embodiment 9A of the present disclosure is shown. The methane generation system 58A according to Embodiment 9A has Fig. 9The methane generation system 58 according to the ninth embodiment shown is a structure in which the heat fusion passage 5 is removed. That is, in the methane generation system 58 according to the ninth embodiment, there is a structure in which there is no heat fusion flow path 5 and only the first preliminary heat exchanger 28 is provided. In this case, the water supply path 2 having the first preliminary heat exchanger 28 can also be regarded as one of the heat fusion flow paths, which can promote electrolysis in the SOEC co-electrolysis device 10 and improve the methane conversion efficiency of the methane reactor 11. In addition, in the structure having the first preliminary heat exchanger 28 described in the following embodiments, it is also possible to set it to a structure without the heat fusion flow path 5. [Implementation 10]

[0082] Below, refer to Fig.10 The methane generation system 59 according to the tenth embodiment of the present disclosure will be described. Fig. 9 The same configurations as those in the ninth embodiment are denoted by the same reference numerals and description thereof is omitted, and only configurations different from those in the ninth embodiment are described.

[0083] The methane generation system 59 has the following configuration: a SOEC co-electrolysis device 10 is installed on the upper side of a methane reactor 11. Fig. 9 The methane generation system 58 of the ninth embodiment shown is arranged in a vertical type. Therefore, since the SOEC co-electrolysis device 10 is arranged at a higher position than the methane reactor 11, the temperature difference between the fluids existing near the heat transfer surfaces of the SOEC co-electrolysis device 10 and the methane reactor 11 can be increased. Fig. 9 In addition to the effects obtained by the methane generation system 58 of the ninth embodiment shown, the heat exchange performance between the SOEC co-electrolysis device 10 and the methane reactor 11 can be improved, so the methane conversion efficiency can be improved and the methane generation amount can be stabilized. [Implementation 11]

[0084] Below, refer to Fig.11 The methane generation system 60 according to the embodiment 11 of the present disclosure will be described. Fig. 9 The same configurations as those in the ninth embodiment are denoted by the same reference numerals and description thereof is omitted, and only configurations different from those in the sixth embodiment are described.

[0085] The methane generation system 60 includes at least one of the following parts for heating water or water vapor flowing through the water supply path 2, at a position downstream of the first preliminary heat exchanger 28 with respect to the flow direction of water or water vapor flowing through the water supply path 2: an eighth heat exchanger 23a for heat exchange with external ventilation exhaust heat; a ninth heat exchanger 24a for heat exchange with external air conditioning exhaust heat; a tenth heat exchanger 25a for heat exchange with external hot water supply exhaust heat; an eleventh heat exchanger 26a for heat exchange with external water heater exhaust heat; and a twelfth heat exchanger 27a for heat exchange with external SOFC fuel cell exhaust heat. Here, the eighth heat exchanger 23a, the ninth heat exchanger 24a, the tenth heat exchanger 25a, the eleventh heat exchanger 26a, and the twelfth heat exchanger 27a are provided in the water supply path 2 in such a manner that the heat exchanger with a lower temperature becomes located upstream with respect to the flow direction of water or water vapor flowing through the water supply path 2.

[0086] Therefore, the eighth heat exchanger 23a with the lowest temperature is disposed at the most upstream relative to the flow direction of water or water vapor flowing in the water supply path 2, and the twelfth heat exchanger 27a with the highest temperature is disposed at the most downstream relative to the flow direction of water or water vapor flowing in the water supply path 2. Between the eighth heat exchanger 23a and the twelfth heat exchanger 27a, relative to the flow direction of water or water vapor flowing in the water supply path 2, the ninth heat exchanger 24a, the tenth heat exchanger 25a, and the eleventh heat exchanger 26a are disposed from the upstream side.

[0087] According to such a methane generation system 60, in addition to the first preliminary heat exchanger 28, at least any one of the eighth heat exchanger 23a, the ninth heat exchanger 24a, the tenth heat exchanger 25a, the eleventh heat exchanger 26a, and the twelfth heat exchanger 27a heats the water or water vapor flowing in the water supply path 2. Therefore, since the heat of the water or water vapor supplied to the SOEC co-electrolysis device 10 is further increased, the electrolysis in the SOEC co-electrolysis device 10 can be further promoted.

[0088] exist Fig.11 In the example of , the 8th heat exchange section 23a, the 9th heat exchange section 24a, the 10th heat exchange section 25a, the 11th heat exchange section 26a, and the 12th heat exchange section 27a are all provided, but it is sufficient to provide at least one of them. When the 8th heat exchange section 23a, the 9th heat exchange section 24a, the 10th heat exchange section 25a, the 11th heat exchange section 26a, and the 12th heat exchange section 27a are all provided, the effect of increasing the heat of water or water vapor supplied to the SOEC co-electrolysis device 10 is maximized. [Implementation 12]

[0089] Below, refer to Fig.12 The methane generation system 61 according to the embodiment 12 of the present disclosure will be described. Fig.11 The same configurations as in the eleventh embodiment are denoted by the same reference numerals and descriptions thereof are omitted, and only configurations different from those in the eighth embodiment are described.

[0090] The methane generation system 61 has the following configuration: a SOEC co-electrolysis device 10 is installed on the upper side of a methane reactor 11. Fig.11 The methane generation system 60 of the embodiment 11 shown is arranged in a vertical type. Therefore, since the SOEC co-electrolysis device 10 is arranged at a higher position than the methane reactor 11, the temperature difference between the fluids existing near the heat transfer surfaces of the SOEC co-electrolysis device 10 and the methane reactor 11 can be increased. Fig.11 In addition to the effects obtained by the methane generation system 60 of the illustrated embodiment 11, the heat exchange performance between the SOEC co-electrolysis device 10 and the methane reactor 11 can be improved, thereby improving the methane conversion efficiency and stabilizing the methane generation amount. [Implementation 13]

[0091] Below, refer to Fig.13 The methane generation system 62 according to the embodiment 13 of the present disclosure will be described. Figure 7 The same configurations as in the seventh embodiment are denoted by the same reference numerals and descriptions thereof are omitted, and only configurations different from those in the seventh embodiment are described.

[0092] Methane generation system 62 Figure 7 The methane production system 56 of the seventh embodiment shown includes a second preliminary heat exchange section 29 for heating carbon dioxide flowing through the carbon dioxide supply path 3 by the reaction heat of the methane reactor 11 .

[0093] In such a methane generation system 62, since the heat of carbon dioxide supplied to the SOEC co-electrolysis device 10 increases, electrolysis in the SOEC co-electrolysis device 10 can be promoted. Furthermore, by removing heat generated from the methane reactor 11, methane conversion efficiency can be improved. [Implementation 14]

[0094] Below, refer to Fig.14 The methane generation system 63 according to the embodiment 14 of the present disclosure will be described. Fig.13 The same structures as those in the thirteenth embodiment are denoted by the same reference numerals and description thereof is omitted, and only structures different from those in the ninth embodiment are described.

[0095] The methane generation system 63 has the following configuration: a SOEC co-electrolysis device 10 is installed on the upper side of a methane reactor 11. Fig.13 The methane generation system 62 of the embodiment 13 shown is arranged in a vertical type. Therefore, since the SOEC co-electrolysis device 10 is arranged at a higher position than the methane reactor 11, the temperature difference between the fluids existing near the heat transfer surfaces of the SOEC co-electrolysis device 10 and the methane reactor 11 can be increased. Fig.13 In addition to the effects obtained by the methane generation system 62 of the illustrated embodiment 13, the heat exchange performance between the SOEC co-electrolysis device 10 and the methane reactor 11 can be improved, thereby improving the methane conversion efficiency and stabilizing the methane generation amount. [Implementation 15]

[0096] Below, refer to Fig.15 The methane generation system 64 according to Embodiment 15 of the present disclosure will be described. Figure 7 The same configurations as in the seventh embodiment are denoted by the same reference numerals and descriptions thereof are omitted, and only configurations different from those in the seventh embodiment are described.

[0097] Methane generation system 64 Figure 7 The methane production system 56 of the seventh embodiment shown includes a third preliminary heat exchanger 35 that heats water or steam flowing through the water supply path 2 and carbon dioxide flowing through the carbon dioxide supply path 3 using the reaction heat of the methane reactor 11 .

[0098] In such a methane generation system 64, since the heat of water or steam and carbon dioxide supplied to the SOEC co-electrolysis device 10 increases, electrolysis in the SOEC co-electrolysis device 10 can be promoted. Furthermore, the methane reactor 11 exchanges heat with the fluids such as water or steam and carbon dioxide. Therefore, more heat can be removed from the heat generated by the methane reactor 11, and the methane conversion efficiency can be improved.

[0099] Here, in the third preliminary heat exchange section 35, the water or water vapor flowing in the water supply path 2 may be mixed with the carbon dioxide flowing in the carbon dioxide supply path 3. Since a gas-liquid two-phase flow is formed by mixing, a more complex flow can be formed. For example, the turbulence generated by the formation of the gas-liquid two-phase flow can improve the heat transfer performance from the methane reactor 11 to the gas-liquid two-phase flow. [Implementation 16]

[0100] Below, refer to Fig.16 The methane generation system 65 according to Embodiment 16 of the present disclosure will be described. Fig.15The same structures as the illustrated embodiment 15 are marked with the same figure marks and their descriptions are omitted, and only the structures different from the embodiment 15 are described.

[0101] The methane generation system 65 has the following configuration: a SOEC co-electrolysis device 10 is installed on the upper side of a methane reactor 11. Fig.15 The methane generation system 64 of the embodiment 15 shown is arranged in a vertical type. Therefore, since the SOEC co-electrolysis device 10 is arranged at a higher position than the methane reactor 11, the temperature difference between the fluids existing near the heat transfer surfaces of the SOEC co-electrolysis device 10 and the methane reactor 11 can be increased. Fig.15 In addition to the effects obtained by the methane generation system 64 of the illustrated embodiment 15, the heat exchange performance between the SOEC co-electrolysis device 10 and the methane reactor 11 can be improved, thereby improving the methane conversion efficiency and stabilizing the methane generation amount. [Implementation 17]

[0102] Below, refer to Fig.17 The methane generation system 66 according to Embodiment 17 of the present disclosure will be described. Fig. 9 The same configurations as those in the ninth embodiment are denoted by the same reference numerals and description thereof is omitted, and only configurations different from those in the ninth embodiment are described.

[0103] Methane generation system 66 Fig. 9 In the methane production system 58 of the ninth embodiment shown, the water supply path 2 is provided with an ejector 40 for using water or steam flowing in the water supply path 2 as a driving fluid, and the carbon dioxide supply path 3 is connected to the SOEC co-electrolysis device 10 via the ejector 40 .

[0104] According to such a methane generation system 66, the carbon dioxide flowing through the carbon dioxide supply path 3 is attracted by the flow of water or water vapor as the driving fluid of the ejector 40. That is, by using a fluid machine such as a blower (not shown) that moves the carbon dioxide flowing through the carbon dioxide supply path 3 to the SOEC co-electrolysis device 10 together with the ejector 40, the power of the fluid machine can be reduced. In this way, the energy required for the operation of the methane generation system 66 can be reduced. [Implementation 18]

[0105] Below, refer to Fig.18 The methane generation system 67 according to the embodiment 18 of the present disclosure will be described. Fig.17 The same structures as the illustrated embodiment 17 are denoted by the same reference numerals and descriptions thereof are omitted, and only structures different from the embodiment 17 are described.

[0106] The methane generation system 67 has the following configuration: a SOEC co-electrolysis device 10 is installed on the upper side of a methane reactor 11. Fig.17 The methane generation system 66 of the embodiment 17 shown is arranged in a vertical type. Therefore, since the SOEC co-electrolysis device 10 is arranged at a higher position than the methane reactor 11, the temperature difference between the fluids existing near the heat transfer surfaces of the SOEC co-electrolysis device 10 and the methane reactor 11 can be increased. Fig.17 In addition to the effects obtained by the methane generation system 66 of the embodiment 17 shown, the heat exchange performance between the SOEC co-electrolysis device 10 and the methane reactor 11 can also be improved, so the methane conversion efficiency can be improved and the methane generation amount can be stabilized. [Implementation 19]

[0107] Below, refer to Fig.19 The methane generation system 68 according to Embodiment 19 of the present disclosure will be described. Fig.13 The same structures as the illustrated embodiment 13 are denoted by the same reference numerals and descriptions thereof are omitted, and only structures different from the embodiment 13 are described.

[0108] Methane generation system 68 Fig.13 In the methane production system 62 of the thirteenth embodiment shown, the carbon dioxide supply path 3 is provided with an ejector 40 for using the carbon dioxide flowing in the carbon dioxide supply path 3 as a driving fluid, and the water supply path 2 is connected to the SOEC co-electrolysis device 10 via the ejector 40 .

[0109] According to such a methane generation system 62, water or water vapor flowing in the water supply path 2 is attracted by the flow of carbon dioxide as the driving fluid of the ejector 40. That is, by using a fluid machine such as a pump or a blower (not shown) that moves the water or water vapor flowing in the water supply path 2 to the SOEC co-electrolysis device 10 together with the ejector 40, the power of the fluid machine can be reduced. In this way, the energy required for the operation of the methane generation system 68 can be reduced. [Implementation 20]

[0110] Below, refer to Fig. 20 A methane generation system 69 according to Embodiment 20 of the present disclosure will be described. Fig.19 The same structures as the illustrated embodiment 19 are denoted by the same reference numerals and descriptions thereof are omitted, and only structures different from the embodiment 19 are described.

[0111] The methane generation system 69 has the following configuration: a SOEC co-electrolysis device 10 is installed on the upper side of a methane reactor 11. Fig.19The methane generation system 68 of the embodiment 19 shown is arranged in a vertical type. Therefore, since the SOEC co-electrolysis device 10 is arranged at a higher position than the methane reactor 11, the temperature difference between the fluids existing near the heat transfer surfaces of the SOEC co-electrolysis device 10 and the methane reactor 11 can be increased. Fig.19 In addition to the effects obtained by the methane generation system 68 of the embodiment 19 shown, the heat exchange performance between the SOEC co-electrolysis device 10 and the methane reactor 11 can also be improved, so the methane conversion efficiency can be improved and the methane generation amount can be stabilized. [Implementation 21]

[0112] Below, refer to Fig.21 A methane generation system 70 according to Embodiment 21 of the present disclosure will be described. Fig.19 The same structures as the illustrated embodiment 19 are denoted by the same reference numerals and descriptions thereof are omitted, and only structures different from the embodiment 19 are described.

[0113] The methane generation system 70 is Fig.19 In the methane generation system 68 of the illustrated embodiment 19, at least one of the following parts is provided at a position upstream of the ejector 40 with respect to the flow direction of water or water vapor flowing in the water supply path 2: a 13th heat exchanger 23b for heat exchange with external ventilation exhaust heat; a 14th heat exchanger 24b for heat exchange with external air conditioning exhaust heat; a 15th heat exchanger 25b for heat exchange with external hot water supply exhaust heat; a 16th heat exchanger 26b for heat exchange with external water heater exhaust heat; and a 17th heat exchanger 27b for heat exchange with external SOFC fuel cell exhaust heat. Here, the 13th heat exchanger 23b, the 14th heat exchanger 24b, the 15th heat exchanger 25b, the 16th heat exchanger 26b, and the 17th heat exchanger 27b are provided in the water supply path 2 with respect to the flow direction of water or water vapor flowing in the water supply path 2 in such a manner that the heat exchanger with a lower temperature is arranged on the upstream side.

[0114] Therefore, the 13th heat exchanger 23b with the lowest temperature is arranged at the most upstream relative to the flow direction of water or water vapor flowing in the water supply path 2, and the 17th heat exchanger 27b with the highest temperature is arranged at the most downstream relative to the flow direction of water or water vapor flowing in the water supply path 2. Between the 13th heat exchanger 23b and the 17th heat exchanger 27b, the 14th heat exchanger 24b, the 15th heat exchanger 25b, and the 16th heat exchanger 26b are arranged from the upstream side relative to the flow direction of water or water vapor flowing in the water supply path 2.

[0115] According to such a methane generation system 60, water or water vapor flowing in the water supply path 2 before being sucked by the ejector 40 is heated by at least any one of the 13th heat exchange section 23b, the 14th heat exchange section 24b, the 15th heat exchange section 25b, the 16th heat exchange section 26b, and the 17th heat exchange section 27b. Therefore, the water or water vapor flowing in the water supply path 2 sucked by the ejector 40 can be converted into water vapor in a gas state. Therefore, the suction effect obtained by the ejector 40 can be obtained more. That is, by using a fluid machine such as a pump or a blower (not shown) that moves the water or water vapor flowing in the water supply path 2 to the SOEC co-electrolysis device 10 and the ejector 40, the power of the above-mentioned fluid machine can be reduced. In this way, the energy required for the operation of the methane generation system 70 can be reduced.

[0116] exist Fig.21 In the example, the 13th heat exchange section 23b, the 14th heat exchange section 24b, the 15th heat exchange section 25b, the 16th heat exchange section 26b, and the 17th heat exchange section 27b are all provided, but it is sufficient to provide at least one of them. When the 13th heat exchange section 23b, the 14th heat exchange section 24b, the 15th heat exchange section 25b, the 16th heat exchange section 26b, and the 17th heat exchange section 27b are all provided, the degree of conversion of water or water vapor sucked by the ejector 40 into water vapor in a gas state is the highest, and the effect of increasing the heat of water or water vapor supplied to the SOEC co-electrolysis device 10 is the greatest. [Implementation 22]

[0117] Below, refer to Fig. 22 A methane generation system 71 according to Embodiment 22 of the present disclosure will be described. Fig.21 The same structures as in the illustrated embodiment 21 are denoted by the same reference numerals and description thereof is omitted, and only the structures different from the embodiment 21 are described.

[0118] The methane generation system 71 has the following configuration: a SOEC co-electrolysis device 10 is installed on the upper side of a methane reactor 11. Fig.21 The methane generation system 70 of the embodiment 21 shown is arranged in a vertical type. Therefore, since the SOEC co-electrolysis device 10 is arranged at a higher position than the methane reactor 11, the temperature difference between the fluids existing near the heat transfer surfaces of the SOEC co-electrolysis device 10 and the methane reactor 11 can be increased. Fig.21 In addition to the effects obtained by the methane generation system 70 of the illustrated embodiment 21, the heat exchange performance between the SOEC co-electrolysis device 10 and the methane reactor 11 can be improved, thereby improving the methane conversion efficiency and stabilizing the methane generation amount. [Implementation 23]

[0119] Below, refer to Fig.23 The methane generation system 72 according to the embodiment 23 of the present disclosure will be described. Fig. 9 The same configurations as those in the ninth embodiment are denoted by the same reference numerals and description thereof is omitted, and only configurations different from those in the ninth embodiment are described.

[0120] The methane generation system 72 is Fig. 9 In the methane generation system 58 of the ninth embodiment shown, relative to the flow direction of water or water vapor flowing in the water supply path 2, at a position upstream of the first preliminary heat exchange section 28, there is at least one of the following parts for heating the water or water vapor flowing in the water supply path 2: an eighth heat exchange section 23a for performing heat exchange with external ventilation exhaust heat; a ninth heat exchange section 24a for performing heat exchange with external air-conditioning exhaust heat; a tenth heat exchange section 25a for performing heat exchange with external hot water supply exhaust heat; an eleventh heat exchange section 26a for performing heat exchange with external water heater exhaust heat; and a twelfth heat exchange section 27a for performing heat exchange with external SOFC fuel cell exhaust heat. Here, the 8th heat exchange section 23a, the 9th heat exchange section 24a, the 10th heat exchange section 25a, the 11th heat exchange section 26a, and the 12th heat exchange section 27a are arranged on the water supply path 2 in a manner such that the heat exchange section with a lower temperature is arranged closer to the upstream side relative to the flow direction of water or water vapor flowing in the water supply path 2.

[0121] Therefore, the eighth heat exchanger 23a with the lowest temperature is disposed at the most upstream relative to the flow direction of water or water vapor flowing in the water supply path 2, and the twelfth heat exchanger 27a with the highest temperature is disposed at the most downstream relative to the flow direction of water or water vapor flowing in the water supply path 2. Between the eighth heat exchanger 23a and the twelfth heat exchanger 27a, relative to the flow direction of water or water vapor flowing in the water supply path 2, the ninth heat exchanger 24a, the tenth heat exchanger 25a, and the eleventh heat exchanger 26a are disposed from the upstream side.

[0122] Furthermore, in the water supply path 2 , a second heater 22 a for heating water or water vapor flowing in the water supply path 2 is provided at a position downstream of the first preliminary heat exchange section 28 .

[0123] According to such a methane generation system 72, in addition to the heat generated by the methane reactor 11, the water or water vapor flowing in the water supply path 2 can be heated by at least any one of the eighth heat exchanger 23a, the ninth heat exchanger 24a, the tenth heat exchanger 25a, the eleventh heat exchanger 26a, and the twelfth heat exchanger 27a and the second heater 22a. Therefore, since the heat of the water or water vapor supplied to the SOEC co-electrolysis device 10 increases, the electrolysis in the SOEC co-electrolysis device 10 can be promoted. Furthermore, by removing the heat generated from the methane reactor 11, the methane conversion efficiency can be improved.

[0124] exist Fig.23 In the example of , the 8th heat exchange section 23a, the 9th heat exchange section 24a, the 10th heat exchange section 25a, the 11th heat exchange section 26a, and the 12th heat exchange section 27a are all provided, but it is sufficient to provide at least one of them. When the 8th heat exchange section 23a, the 9th heat exchange section 24a, the 10th heat exchange section 25a, the 11th heat exchange section 26a, and the 12th heat exchange section 27a are all provided, the effect of increasing the heat of water or water vapor supplied to the SOEC co-electrolysis device 10 is maximized. [Implementation 24]

[0125] Below, refer to Fig.24 The methane generation system 73 according to the embodiment 24 of the present disclosure will be described. Fig.23 The same structures as the illustrated embodiment 23 are marked with the same figure marks and their descriptions are omitted, and only the structures different from the embodiment 23 are described.

[0126] The methane generation system 73 has the following structure: a SOEC co-electrolysis device 10 is installed on the upper side of the methane reactor 11. Fig.23 The methane generation system 72 of the embodiment 23 shown is arranged in a vertical type. Therefore, since the SOEC co-electrolysis device 10 is arranged at a higher position than the methane reactor 11, the temperature difference between the fluids existing near the heat transfer surfaces of the SOEC co-electrolysis device 10 and the methane reactor 11 can be increased. Fig.23 In addition to the effects obtained by the methane generation system 72 of the illustrated embodiment 23, the heat exchange performance between the SOEC co-electrolysis device 10 and the methane reactor 11 can be improved, thereby improving the methane conversion efficiency and stabilizing the methane generation amount. [Implementation 25]

[0127] Below, refer to Fig.25 The methane generation system 74 according to the embodiment 25 of the present disclosure will be described. Fig.23The same structures as the illustrated embodiment 23 are marked with the same figure marks and their descriptions are omitted, and only the structures different from the embodiment 23 are described.

[0128] Methane generation system 74 Fig.23 The methane production system 72 of the illustrated embodiment 23 is different in that the twelfth heat exchange section 27a is located between the first preliminary heat exchange section 28 and the second heater 22a.

[0129] In such a methane generation system 74, the 12th heat exchanger 27a is provided on the downstream side of the 1st preliminary heat exchanger 28 with respect to the flow direction of water or water vapor flowing in the water supply path 2. Therefore, even when the 12th heat exchanger 27a, which has the highest temperature among the 8th heat exchanger 23a to the 12th heat exchanger 27a, heats the water or water vapor flowing in the water supply path 2 at a temperature higher than that of the methane reactor 11, the heating of the methane reactor 11 and the 12th heat exchanger 27a can be effectively utilized. [Implementation 26]

[0130] Below, refer to Fig.26 The methane generation system 75 according to the embodiment 26 of the present disclosure will be described. Fig.25 The same structures as the illustrated embodiment 25 are marked with the same figure marks and their descriptions are omitted, and only the structures different from the embodiment 25 are described.

[0131] The methane generation system 75 has the following configuration: a SOEC co-electrolysis device 10 is installed on the upper side of a methane reactor 11. Fig.25 The methane generation system 74 of the embodiment 25 shown is arranged in a vertical type. Therefore, since the SOEC co-electrolysis device 10 is arranged at a higher position than the methane reactor 11, the temperature difference between the fluids existing near the heat transfer surfaces of the SOEC co-electrolysis device 10 and the methane reactor 11 can be increased. Fig.25 In addition to the effects obtained by the methane generation system 74 of the illustrated embodiment 25, the heat exchange performance between the SOEC co-electrolysis device 10 and the methane reactor 11 can be improved, thereby improving the methane conversion efficiency and stabilizing the methane generation amount.

[0132] In addition, the technical scope of the present disclosure is not limited to the above-described embodiments, and various modifications can be made within the scope of the present disclosure defined in the claims.

[0133] For example, in Fig.13 and Fig.14In the methane generation system 62 of the thirteenth embodiment and the methane generation system 63 of the fourteenth embodiment shown, at least one of the following parts may be provided on the downstream side of the second preliminary heat exchanger 29 in the flow direction of the carbon dioxide flowing through the carbon dioxide supply path 3: the eighth heat exchanger 23a for heat exchange with the external ventilation exhaust heat; the ninth heat exchanger 24a for heat exchange with the external air conditioning exhaust heat; the tenth heat exchanger 25a for heat exchange with the external hot water supply exhaust heat; the eleventh heat exchanger 26a for heat exchange with the external water heater exhaust heat; the twelfth heat exchanger 27a for heat exchange with the external SOFC fuel cell exhaust heat. In addition, a second heater 22a may be further provided on the downstream side of the twelfth heat exchanger 27a in the flow direction of the carbon dioxide flowing through the carbon dioxide supply path 3.

[0134] In this case, Fig.11 and Fig.12 The methane generation system 60 of the embodiment 11 shown is similar to the methane generation system 61 of the embodiment 12. In addition to the second preliminary heat exchanger 29, the carbon dioxide flowing in the carbon dioxide supply path 3 is heated by at least one of the eighth heat exchanger 23a, the ninth heat exchanger 24a, the tenth heat exchanger 25a, the eleventh heat exchanger 26a, and the twelfth heat exchanger 27a. Therefore, since the heat of the carbon dioxide supplied to the SOEC co-electrolysis device 10 is further increased, the electrolysis in the SOEC co-electrolysis device 10 can be further promoted. This effect is the greatest when the eighth heat exchanger 23a, the ninth heat exchanger 24a, the tenth heat exchanger 25a, the eleventh heat exchanger 26a, and the twelfth heat exchanger 27a are all provided. When the second heater 22a is further provided, this effect can be further enhanced.

[0135] For example, in Fig.13 and Fig.14In the methane generation system 62 of the thirteenth embodiment and the methane generation system 63 of the fourteenth embodiment shown, at least one of the following parts is provided on the upstream side of the second preliminary heat exchange section 29 in the flow direction of the carbon dioxide flowing through the carbon dioxide supply path 3: the eighth heat exchange section 23a for heat exchange with the external ventilation exhaust heat; the ninth heat exchange section 24a for heat exchange with the external air conditioning exhaust heat; the tenth heat exchange section 25a for heat exchange with the external hot water supply exhaust heat; the eleventh heat exchange section 26a for heat exchange with the external water heater exhaust heat; and the twelfth heat exchange section 27a for heat exchange with the external SOFC fuel cell exhaust heat. In this case, the second heater 22a may be further provided on the downstream side of the second preliminary heat exchange section 29 in the flow direction of the carbon dioxide flowing through the carbon dioxide supply path 3.

[0136] In this case, Fig.23 and Fig.24 The methane generation system 72 of the embodiment 23 shown is similar to the methane generation system 73 of the embodiment 24. In addition to the second preliminary heat exchanger 29, the carbon dioxide flowing in the carbon dioxide supply path 3 is heated by at least any one of the eighth heat exchanger 23a, the ninth heat exchanger 24a, the tenth heat exchanger 25a, the eleventh heat exchanger 26a, and the twelfth heat exchanger 27a. Therefore, since the heat of the carbon dioxide supplied to the SOEC co-electrolysis device 10 is further increased, the electrolysis in the SOEC co-electrolysis device 10 can be further promoted. This effect is the greatest when the eighth heat exchanger 23a, the ninth heat exchanger 24a, the tenth heat exchanger 25a, the eleventh heat exchanger 26a, and the twelfth heat exchanger 27a are all provided. When the second heater 22a is further provided, this effect can be further enhanced.

[0137] Likewise, in Fig.21 and Fig. 22 In the methane generation system 70 of embodiment 21 and the methane generation system 71 of embodiment 22 shown, at least any one of the following parts can be provided on the upstream side or downstream side of the second preliminary heat exchange section 29 on the carbon dioxide supply path 3 in the flow direction of the carbon dioxide flowing through the carbon dioxide supply path 3: the eighth heat exchange section 23a for heat exchange with external ventilation exhaust heat; the ninth heat exchange section 24a for heat exchange with external air conditioning exhaust heat; the tenth heat exchange section 25a for heat exchange with external hot water supply exhaust heat; the eleventh heat exchange section 26a for heat exchange with external water heater exhaust heat; and the twelfth heat exchange section 27a for heat exchange with external SOFC fuel cell exhaust heat.

[0138] In this case, in addition to the second preliminary heat exchanger 29, at least any one of the eighth heat exchanger 23a, the ninth heat exchanger 24a, the tenth heat exchanger 25a, the eleventh heat exchanger 26a, and the twelfth heat exchanger 27a is used to heat the carbon dioxide flowing through the carbon dioxide supply path 3. Therefore, since the heat amount of the carbon dioxide supplied to the SOEC co-electrolysis device 10 is further increased, the electrolysis in the SOEC co-electrolysis device 10 can be further promoted. This effect is the greatest when all of the eighth heat exchanger 23a, the ninth heat exchanger 24a, the tenth heat exchanger 25a, the eleventh heat exchanger 26a, and the twelfth heat exchanger 27a are provided.

[0139] From the fourth embodiment onwards, the SOEC co-electrolysis device 10 is provided at a position higher than the methane reactor 11 and is arranged in a vertical configuration. However, the methane generation system 50 of the first embodiment and the methane generation system 51 of the second embodiment may be provided in a configuration in which the SOEC co-electrolysis device 10 is provided at a position higher than the methane reactor 11 and is arranged in a vertical configuration. In this case, the same effect as that of the fourth embodiment can be obtained.

[0140] In the description of Embodiment 3, it is described that the SOEC co-electrolysis device 10 and the methane reactor 11 can be physically integrated, but in other embodiments, the SOEC co-electrolysis device 10 and the methane reactor 11 can also be physically integrated. Description of Reference Numerals

[0141] 1 Power supply path

[0142] 2 Water supply route

[0143] 3 Carbon dioxide supply route

[0144] 4 Connection Path

[0145] 5. Thermal fusion flow path

[0146] 6 Gas Path

[0147] 10 SOEC co-electrolysis device

[0148] 11 Methane reactor 11

[0149] 20 1st heat exchange unit

Claims

1. A methane generation system, wherein: The methane generation system has: a water supply path that supplies water or water vapor; a carbon dioxide supply path that supplies carbon dioxide; a power supply path that supplies power; A SOEC co-electrolysis device, the SOEC co-electrolysis device connecting the water supply path, the carbon dioxide supply path and the power supply path; Methane reactor; A connection path connecting the SOEC co-electrolysis device with the methane reactor; as well as A first heat exchange unit performs heat exchange between the SOEC co-electrolysis device and the methane reactor.

2. The methane generation system according to claim 1, wherein: The SOEC co-electrolysis device is arranged at a higher position than the methane reactor.

3. The methane generation system according to claim 1 or 2, wherein: The methane generation system includes a heat-fused flow path for supplying at least a portion of the water or steam released from the methane reactor to the SOEC co-electrolysis device.

4. The methane generation system according to claim 3, wherein: The SOEC co-electrolysis device and the methane reactor are physically integrated, and the heat fusion flow path includes a second heat exchange portion that performs heat exchange with external exhaust heat.

5. The methane generation system according to claim 4, wherein: The heat fusion flow path is provided with a heater.

6. The methane generation system according to claim 4 or 5, wherein: The above-mentioned second heat exchange part has at least any one of the following parts: a third heat exchange part for heat exchange with ventilation exhaust heat; a fourth heat exchange part for heat exchange with air conditioning exhaust heat; a fifth heat exchange part for heat exchange with hot water supply exhaust heat; a sixth heat exchange part for heat exchange with water heater exhaust heat; and a seventh heat exchange part for heat exchange with SOFC fuel cell exhaust heat.

7. The methane generation system according to claim 6, wherein: The methane generation system includes a preliminary heat exchange unit that utilizes the reaction heat of the methane reactor to heat the water or steam supplied from the water supply path to the SOEC co-electrolysis device.

8. The methane generation system according to claim 7, wherein: The water supply path includes an ejector, and the carbon dioxide supply path is connected to the SOEC co-electrolysis device via the ejector.

9. The methane generation system according to claim 6, wherein: The methane generation system includes a preliminary heat exchange unit that utilizes the reaction heat of the methane reactor to heat the carbon dioxide supplied to the SOEC co-electrolysis device.

10. The methane generation system according to claim 7, wherein: The methane generation system includes a preliminary heat exchange unit that utilizes the reaction heat of the methane reactor to heat the carbon dioxide supplied to the SOEC co-electrolysis device.

11. The methane generation system according to claim 9, wherein: The carbon dioxide supply path includes an ejector, and the water supply path is connected to the SOEC co-electrolysis device via the ejector.

12. The methane generation system according to claim 7, wherein: The water supply path has at least any one of the following parts: an 8th heat exchange section for heat exchange with ventilation exhaust heat; a 9th heat exchange section for heat exchange with air conditioning exhaust heat; a 10th heat exchange section for heat exchange with hot water supply exhaust heat; an 11th heat exchange section for heat exchange with water heater exhaust heat; and a 12th heat exchange section for heat exchange with SOFC fuel cell exhaust heat.

13. The methane generation system according to claim 9 or 11, wherein: The water supply path has at least any one of the following parts: an 8th heat exchange section for heat exchange with ventilation exhaust heat; a 9th heat exchange section for heat exchange with air conditioning exhaust heat; a 10th heat exchange section for heat exchange with hot water supply exhaust heat; an 11th heat exchange section for heat exchange with water heater exhaust heat; and a 12th heat exchange section for heat exchange with SOFC fuel cell exhaust heat.

14. The methane generation system according to claim 12, wherein: The water supply path is provided with a heater.

15. The methane generation system according to any one of claims 6 to 14, wherein: With respect to the flow direction of the water or the water vapor flowing in the heat fusion flow path, among the third heat exchange section, the fourth heat exchange section, the fifth heat exchange section, the sixth heat exchange section, and the seventh heat exchange section, the lower the temperature of the heat exchange section, the closer to the upstream side it is configured.

16. The methane generation system according to any one of claims 12 to 15, wherein: With respect to the flow direction of the water or the water vapor flowing in the heat fusion flow path, among the 8th heat exchange part, the 9th heat exchange part, the 10th heat exchange part, the 11th heat exchange part, and the 12th heat exchange part, the lower the temperature of the heat exchange part, the closer to the upstream side it is configured.

17. A methane generation system, wherein: The methane generation system has: a water supply path that supplies water or water vapor; a carbon dioxide supply path that supplies carbon dioxide; a power supply path that supplies power; A SOEC co-electrolysis device, the SOEC co-electrolysis device is connected to the water supply path, the carbon dioxide supply path and the power supply path; Methane reactor; A connection path connecting the SOEC co-electrolysis device with the methane reactor; a first heat exchange section for performing heat exchange between the SOEC co-electrolysis device and the methane reactor; as well as A preliminary heat exchange unit is provided for heating the water or steam supplied from the water supply path to the SOEC co-electrolysis device by utilizing the reaction heat of the methane reactor.

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