Electrolysis System

Abstract

To provide a system in which carbon dioxide can be electrolyzed without carrying out dehydration treatment.SOLUTION: An electrolysis system (10) includes: an absorber (12) for absorbing carbon dioxide into a lithium composite oxide; a release device (14) for heating the lithium composite oxide in which the carbon dioxide is absorbed to release the carbon dioxide from the lithium composite oxide; a solid oxide type electrolysis stack (18) that electrolyzes the carbon dioxide released by the release device (14); and a transfer mechanism (50) for transferring the lithium composite oxide in which the carbon dioxide is absorbed by the absorber (12) to the release device (14).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electrolysis system for electrolyzing carbon dioxide. [Background technology]

[0002] In recent years, methods have been developed for producing hydrocarbons from carbon monoxide generated by electrolysis of carbon dioxide. As a technology for recovering this carbon dioxide, a system for separating and recovering carbon dioxide in exhaust gas is disclosed in the following Patent Document 1. This system includes a membrane dehydrator that reduces the water concentration in the exhaust gas, and a separator / concentrator that uses a zeolite membrane to produce a gas in which carbon dioxide is concentrated from the gas with a reduced water concentration. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-236123 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the system of Patent Document 1 requires dehydration of the exhaust gas, which tends to require a large amount of energy. Therefore, there was a need to develop a system that can electrolyze carbon dioxide without dehydration.

[0005] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]

[0006] An aspect of the present invention is an electrolysis system for electrolyzing carbon dioxide, comprising: an absorption device having a reaction chamber in which a lithium composite oxide is heated to an absorption temperature that is a temperature necessary for absorbing the carbon dioxide, and causing the lithium composite oxide to absorb the carbon dioxide in the reaction chamber; a release device that heats the lithium composite oxide in which the carbon dioxide has been absorbed to a release temperature that is a temperature necessary for the lithium composite oxide to release the carbon dioxide, thereby releasing the carbon dioxide from the lithium composite oxide; a solid oxide electrolysis stack that electrolyzes the carbon dioxide released by the release device; and a transfer mechanism that transfers the lithium composite oxide in which the carbon dioxide has been absorbed by the absorption device to the release device. [Effects of the Invention]

[0007] According to the above-described embodiment, carbon dioxide can be collected without dehydration treatment. Furthermore, since the carbon dioxide is transferred from the absorption device to the release device using the lithium composite oxide as a carrier of carbon dioxide, the carbon dioxide can be transported without being pressurized. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of an electrolysis system according to an embodiment. [Figure 2] FIG. 2 is a flowchart showing the procedure of the adjustment process performed by the transport control unit. [Figure 3] FIG. 3 is a schematic diagram showing a partial configuration of an electrolysis system according to Modification 1. [Figure 4] FIG. 4 is a schematic diagram showing a partial configuration of an electrolysis system according to Modification 2. DETAILED DESCRIPTION OF THE INVENTION

[0009] FIG. 1 is a schematic diagram showing the configuration of an electrolysis system 10 according to an embodiment. The electrolysis system 10 is a system that electrolyzes carbon dioxide. In the electrolysis system 10, a lithium composite oxide is used as a carrier for transporting carbon dioxide. Examples of lithium composite oxides include Li2ZrO3, Li4SiO4, Li4TiO4, and Li2CuO2.

[0010] Lithium composite oxides have the property of absorbing and releasing carbon dioxide depending on the temperature. The rate at which lithium composite oxides absorb carbon dioxide is temperature dependent. For example, Li2ZrO3 has the highest carbon dioxide absorption rate around 500°C and releases carbon dioxide at approximately 680°C.

[0011] The electrolysis system 10 includes an absorber 12, an emitter 14, a steam generator 16, a solid oxide electrolysis stack 18, a synthesizer 20, a first heat exchanger 22, a first dehumidifier 24, a second heat exchanger 26, and a second dehumidifier 28.

[0012] The absorber 12 has a temperature sensor 30 and a temperature regulator 32. The temperature sensor 30 detects the temperature of the absorber 12. The temperature regulator 32 adjusts the temperature of the absorber 12 so that the temperature detected by the temperature sensor 30 is maintained at a predetermined absorption temperature. The absorption temperature is the temperature required for the lithium composite oxide to absorb carbon dioxide, and is set depending on the type of lithium composite oxide.

[0013] Carbon dioxide is supplied to the absorber 12 from a carbon dioxide supply source. The carbon dioxide supply source may be an extraction device that extracts carbon dioxide from the atmosphere, a tank that stores carbon dioxide, or plant equipment that can capture and discharge carbon dioxide. When the carbon dioxide supply source is plant equipment, a mixed fluid containing carbon dioxide and impurities may be supplied from the carbon dioxide supply source. In this case, the absorber 12 may have a carbon dioxide separator that separates carbon dioxide from the mixed fluid. In this case, the temperature regulator 32 may adjust the temperature of the absorber 12 using waste heat energy from the mixed fluid. This allows for greater energy savings than when the temperature regulator 32 is configured using a heater or the like.

[0014] The absorber 12 has a reaction chamber capable of storing carbon dioxide and lithium composite oxide. The reaction chamber is maintained at an absorption temperature by a temperature controller 32. The absorber 12 stores the lithium composite oxide and carbon dioxide in the reaction chamber for a predetermined reaction time. As described above, the absorption rate of carbon dioxide by the lithium composite oxide is temperature-dependent. Therefore, the reaction time is set according to the type of lithium composite oxide and the absorption temperature. The absorber 12 heats the lithium composite oxide at a predetermined absorption temperature for a predetermined reaction time, causing the carbon dioxide to be absorbed by the lithium composite oxide.

[0015] The release device 14 has a temperature sensor 34 and a heater 36. The temperature sensor 34 detects the temperature of the release device 14. The heater 36 heats the release device 14 so that the temperature detected by the temperature sensor 34 is maintained at a predetermined release temperature. The release temperature is a temperature required for the lithium composite oxide to release carbon dioxide, and is set depending on the type of lithium composite oxide.

[0016] The heater 36 may heat the solid oxide electrolysis stack 18 together with the discharge device 14. FIG. 1 shows an example in which the heater 36 heats the solid oxide electrolysis stack 18 together with the discharge device 14. When the heater 36 heats the solid oxide electrolysis stack 18 together with the discharge device 14, the heater 36 is set to the higher of the discharge temperature and the electrolysis temperature. The electrolysis temperature is a temperature required for electrolysis in the solid oxide electrolysis stack 18.

[0017] The release device 14 heats the lithium composite oxide in which carbon dioxide has been absorbed by the heater 36, causing the carbon dioxide to be released from the lithium composite oxide. The release device 14 outputs the carbon dioxide released from the lithium composite oxide to the CO2 supply flow path 38.

[0018] The CO2 supply flow path 38 is a flow path for supplying carbon dioxide from the release device 14 to the solid oxide electrolysis stack 18. The carbon dioxide output to the CO2 supply flow path 38 flows into the solid oxide electrolysis stack 18.

[0019] The steam generator 16 generates steam by heating water supplied from a water generation source. The water generation source may be a water supply device or a tank. The water generation source may also be a plant facility that discharges exhaust gas containing moisture. The steam generator 16 outputs the steam generated by heating the water, etc., to the steam supply flow path 40. When the water source is a plant facility, the steam generator 16 may extract steam from exhaust gas discharged from the plant facility. In this case, energy savings can be achieved compared to generating steam from a water supply device or the like.

[0020] The steam supply flow path 40 is a flow path for supplying water vapor from the steam generator 16 to the CO2 supply flow path 38. The steam supply flow path 40 passes through the first heat exchanger 22 and the heater 36 in this order. The water vapor output to the steam supply flow path 40 is warmed by the first heat exchanger 22 and the heater 36, and flows into the solid oxide electrolysis stack 18 together with carbon dioxide via the CO2 supply flow path 38.

[0021] The solid oxide electrolysis stack 18 electrolyzes carbon dioxide. In this embodiment, the solid oxide electrolysis stack 18 co-electrolyzes carbon dioxide and water vapor. The solid oxide electrolysis stack 18 has a plurality of unit cells. Each unit cell is equipped with a membrane electrode assembly (MEA) in which an electrolytic membrane is sandwiched between an anode electrode and a cathode electrode.

[0022] The solid oxide electrolysis stack 18 is heated to a predetermined temperature or higher. warm In this embodiment, the solid oxide electrolysis stack 18 is heated by a heater 36. warm Furthermore, the solid oxide electrolysis stack 18 supplies externally supplied power between the anode electrode and cathode electrode of each unit cell, and supplies carbon dioxide and water vapor to the cathode electrode of each unit cell. As the temperature of the solid oxide electrolysis stack 18 increases, each unit cell starts electrolysis of carbon dioxide and water vapor. When electrolysis of carbon dioxide and water vapor starts, carbon monoxide and hydrogen are produced at the cathode electrode, and oxygen is produced at the anode electrode.

[0023] The solid oxide electrolysis stack 18 collects oxygen produced in each unit cell and outputs the oxygen to an O2 supply flow path 42. The O2 supply flow path 42 is a flow path for supplying oxygen from the solid oxide electrolysis stack 18 to the oxygen-demanding device. The oxygen-demanding device may be a tank. As described above, when the carbon dioxide supply source is plant equipment, the plant equipment can be the oxygen-demanding device. The oxygen output to the O2 supply flow path 42 flows into the oxygen-demanding device.

[0024] The solid oxide electrolysis stack 18 collects a mixed gas containing carbon monoxide and hydrogen produced in each unit cell and water vapor that was not electrolyzed, and outputs the mixed gas to a gas supply flow path 44. The gas supply flow path 44 is a flow path for supplying carbon monoxide and hydrogen from the solid oxide electrolysis stack 18 to the synthesizer 20. The gas supply flow path 44 passes through the first heat exchanger 22, the first dehumidifier 24, and the second heat exchanger 26 in this order. The mixed gas output to the gas supply flow path 44 is cooled by the first heat exchanger 22. The water vapor contained in the cooled mixed gas is dehumidified by the first dehumidifier 24. The mixed gas from which the water vapor has been dehumidified is warmed by the second heat exchanger 26 and flows into the synthesizer 20.

[0025] The synthesis unit 20 synthesizes hydrocarbons from carbon monoxide and hydrogen through a catalytic reaction. The synthesis unit 20 may synthesize hydrocarbons using the Fischer-Tropsch process. The synthesis unit 20 outputs the hydrocarbons synthesized through the catalytic reaction to the HC supply flow path 46.

[0026] The HC supply flow path 46 is a flow path for supplying hydrocarbons from the synthesis unit 20 to the hydrocarbon-requiring device. The hydrocarbon-requiring device may be a tank. The HC supply flow path 46 passes through the second heat exchanger 26 and the second dehumidifier 28 in this order. The hydrocarbons output to the gas supply flow path 44 are cooled by the second heat exchanger 26. Moisture generated by this cooling is dehumidified by the second dehumidifier 28. The hydrocarbons from which moisture has been dehumidified flow into the hydrocarbon-requiring device.

[0027] The electrolysis system 10 of this embodiment further includes a transfer mechanism 50, a second transfer mechanism 52, and a control device 54.

[0028] The transfer mechanism 50 is a mechanism that transfers the lithium composite oxide from which carbon dioxide has been absorbed by the absorption device 12 to the release device 14. In this embodiment, the lithium composite oxide is formed in a pellet shape. That is, the lithium composite oxide is formed as particles. The transfer mechanism 50 is configured to be able to transfer the lithium composite oxide formed in a pellet shape. The transfer mechanism 50 has a supply path 56, a pump 58, a buffer device 60, and a flow rate adjustment valve 62.

[0029] The supply path 56 is a flow path for supplying the lithium composite oxide particles from the absorber 12 to the release device 14. The pump 58 imparts a flow force to the lithium composite oxide particles. The lithium composite oxide particles to which the flow force is imparted by the pump 58 flow from the absorber 12 to the release device 14 via the supply path 56. Note that if the absorber 12 is placed at a higher position than the release device 14, gravity serves as the flow force. In this case, the pump 58 is not required. Furthermore, a conveying device such as a belt conveyor may be installed in the supply path 56. In this case, the pump 58 is also not required.

[0030] The buffer device 60 is a device that can temporarily store the lithium composite oxide in which carbon dioxide has been absorbed. The buffer device 60 has a storage space that communicates with the supply path 56. The lithium composite oxide in which carbon dioxide has been absorbed is stored in this storage space. A flow rate adjustment valve 62 is provided in the supply path 56 between the buffer device 60 and the release device 14.

[0031] The flow rate adjusting valve 62 is configured to be able to adjust the opening degree of the valve. When the opening degree of the flow rate adjusting valve 62 is at the minimum value (zero), the supply path 56 is closed and the lithium composite oxide is supplied to the release device 14. Things On the other hand, the greater the opening of the flow rate adjusting valve 62, the greater the amount of lithium composite oxide supplied to the release device 14.

[0032] The second transfer mechanism 52 is a mechanism that transfers the lithium composite oxide from which carbon dioxide has been released by the release device 14 to the absorber 12. By providing this second transfer mechanism 52, the lithium composite oxide can circulate between the absorber 12 and the release device 14. The second transfer mechanism 52 is configured to be able to transfer the lithium composite oxide formed into pellets. The second transfer mechanism 52 has a return path 64.

[0033] The return path 64 is a flow path for supplying the lithium composite oxide particles from the release device 14 to the absorber 12. The lithium composite oxide particles to which flow force has been imparted by the pump 58 flow from the release device 14 to the absorber 12 via the return path 64. A second pump separate from the pump 58 may be provided on the return path 64. Also, a transport device such as a belt conveyor may be installed on the return path 64. In this case, the second pump is not necessary.

[0034] The control device 54 has a stack control unit 66 and a transfer control unit 68. The stack control unit 66 controls the power supply device 70 to adjust the voltage value applied between the anode electrode and the cathode electrode of each unit cell of the solid oxide electrolysis stack 18.

[0035] The stack control unit 66 adjusts the voltage value so that the amount of carbon monoxide detected by the carbon monoxide sensor 72 approaches the target carbon monoxide amount. The carbon monoxide sensor 72 detects the amount of carbon monoxide output from the solid oxide electrolysis stack 18. The carbon monoxide sensor 72 is provided, for example, in the gas supply flow path 44 near the solid oxide electrolysis stack 18. The target carbon monoxide amount may be registered in a storage unit such as a memory, or may be calculated based on the amount of carbon monoxide detected by the carbon monoxide sensor 72, etc.

[0036] The transfer control unit 68 starts or stops the transfer of the transfer mechanism 50 based on the temperature of the heater 36 detected by the temperature sensor 34. When the temperature of the heater 36 detected by the temperature sensor 34 exceeds the discharge temperature, the transfer control unit 68 starts the transfer of the transfer mechanism 50. In this embodiment, the transfer control unit 68 drives the pump 58 to start the transfer of the transfer mechanism 50.

[0037] After the transfer mechanism 50 starts transferring, when the temperature of the heater 36 detected by the temperature sensor 34 becomes equal to or lower than the discharge temperature, the transfer control unit 68 stops the transfer of the transfer mechanism 50. In this embodiment, the transfer control unit 68 stops the pump 58 to stop the transfer of the transfer mechanism 50.

[0038] The transfer control unit 68 controls the transfer mechanism 50 to adjust the amount of lithium composite oxide transferred to the release device 14. In the present embodiment, the transfer control unit 68 controls the flow rate adjustment valve 62 of the transfer mechanism 50. The transfer control unit 68 adjusts the aperture of the flow rate adjustment valve 62 based on the amount of carbon dioxide transferred per unit time and the amount of carbon dioxide required per unit time by the solid oxide electrolysis stack 18.

[0039] The amount of carbon dioxide transferred per unit time varies depending on the absorption temperature and reaction time set in the absorber 12. As described above, these absorption temperature and reaction time are set according to the amount of carbon dioxide absorbed. The transfer control unit 68 has absorption information that indicates the amount of carbon dioxide absorbed for each type of lithium composite oxide. The transfer control unit 68 acquires the absorption temperature and reaction time currently set in the absorber 12, and can calculate the amount of carbon dioxide transferred per unit time using the absorption temperature and reaction time and the absorption information.

[0040] The amount of carbon dioxide required per unit time varies depending on the target amount of carbon monoxide. There is a certain relationship between the amount of carbon monoxide produced and the amount of carbon dioxide required to produce that amount of carbon monoxide. The transfer control unit 68 has a table or relational expression that shows this relationship. The transfer control unit 68 obtains the target amount of carbon monoxide currently set for the solid oxide electrolysis stack 18, and can calculate the amount of carbon dioxide required per unit time using the target amount of carbon monoxide and the table or relational expression.

[0041] When the difference between the amount of carbon dioxide transferred per unit time and the amount of carbon dioxide required per unit time by the solid oxide electrolysis stack 18 is within a predetermined range, the transfer control unit 68 sets the opening degree of the flow rate control valve 62 to a pre-registered reference value (reference opening degree).

[0042] On the other hand, if the difference between the amount of carbon dioxide transferred and the amount of carbon dioxide required exceeds a predetermined range and sending If the amount is greater than the required amount, the transfer control unit 68 sets the opening of the flow rate adjustment valve 62 to a value smaller than the reference value. In this case, the transfer control unit 68 reduces the opening of the flow rate adjustment valve 62 in accordance with the difference between the transfer amount and the required amount.

[0043] On the other hand, if the difference between the amount of carbon dioxide transferred and the amount of carbon dioxide required exceeds a predetermined range and sending If the amount is less than the required amount, the transfer control unit 68 sets the opening of the flow rate adjustment valve 62 to be greater than the reference value. In this case, the transfer control unit 68 increases the opening of the flow rate adjustment valve 62 in accordance with the difference between the transfer amount and the required amount.

[0044] Next, an adjustment process will be described in which the transfer control unit 68 adjusts the amount of lithium composite oxide transferred to the release device 14. Fig. 2 is a flowchart showing the procedure of the adjustment process by the transfer control unit 68. The adjustment process may be performed at predetermined intervals, or may be performed only once between the start and stop of transfer by the transfer mechanism 50.

[0045] In step S1, the transfer control unit 68 calculates the amount of carbon dioxide transferred per unit time. That is, the transfer control unit 68 acquires the absorption temperature and reaction time currently set in the absorption device 12, and calculates the amount of carbon dioxide transferred using the absorption temperature and reaction time and absorption information indicating the amount of carbon dioxide absorbed. Once the amount of carbon dioxide transferred has been calculated, the adjustment process proceeds to step S2.

[0046] In step S2, the transfer control unit 68 calculates the required amount of carbon dioxide per unit time required by the solid oxide electrolysis stack 18. That is, the transfer control unit 68 acquires the target amount of carbon monoxide currently set for the solid oxide electrolysis stack 18. Thereafter, the transfer control unit 68 calculates the required amount of carbon dioxide corresponding to the target amount of carbon monoxide using a table or a relational expression indicating the relationship between the amount of carbon monoxide produced and the amount of carbon dioxide required for producing that carbon monoxide. Once the required amount of carbon dioxide is calculated, the adjustment process proceeds to step S3.

[0047] In step S3, the transfer control unit 68 compares the amount of carbon dioxide transferred calculated in step S1 with the amount of carbon dioxide required calculated in step S2. If the difference between the amount of carbon dioxide transferred and the amount of carbon dioxide required is within a predetermined range (step S3: YES), the adjustment process proceeds to step S4. Conversely, if the difference between the amount of carbon dioxide transferred and the amount of carbon dioxide required exceeds the predetermined range (step S3: NO), the adjustment process proceeds to step S5.

[0048] In step S4, the transfer control unit 68 sets the opening degree of the flow rate adjustment valve 62 to a reference value. When the opening degree of the flow rate adjustment valve 62 is set to the reference value, the adjustment process ends.

[0049] In step S5, the transfer control unit 68 determines whether the amount of transferred carbon dioxide is greater than the required amount of carbon dioxide. If the amount of transferred carbon dioxide is greater than the required amount of carbon dioxide (step S5: YES), the adjustment process proceeds to step S6. Conversely, if the amount of transferred carbon dioxide is less than the required amount of carbon dioxide (step S5: NO), the adjustment process proceeds to step S7.

[0050] In step S6, the transfer control unit 68 sets the opening degree of the flow rate adjustment valve 62 to a value smaller than the reference value. When the opening degree of the flow rate adjustment valve 62 is set to a value smaller than the reference value, the adjustment process ends.

[0051] In step S7, the transfer control unit 68 sets the opening degree of the flow rate adjustment valve 62 to be larger than the reference value. When the opening degree of the flow rate adjustment valve 62 is set to be larger than the reference value, the adjustment process ends.

[0052] The above embodiment may be modified as follows.

[0053] (Variation 1) 3 is a schematic diagram showing a partial configuration of an electrolysis system 10 according to Modification 1. The electrolysis system 10 according to Modification 1 further includes a bypass passage 74 and an on-off valve 76 in addition to the components of the above embodiment.

[0054] The bypass path 74 branches off from the supply path 56 between the buffer device 60 and the absorber 12 and merges with the supply path 56 between the buffer device 60 and the discharge device 14. An on-off valve 76 is provided in the bypass path 74. The on-off valve 76 is opened and closed by the transfer control unit 68.

[0055] In this first modification, when the on-off valve 76 of the bypass 74 is opened, the lithium composite oxide output from the bypass 74 is supplied to the release device 14 in addition to the lithium composite oxide output from the buffer device 60. Therefore, the amount of carbon dioxide absorbed by the lithium composite oxide can be increased.

[0056] This modified example is particularly useful when the amount of carbon dioxide required per unit time by the solid oxide electrolysis stack 18 cannot be supplied from the buffer device 60 to the release device 14 even when the flow rate control valve 62 is fully opened.

[0057] (Variation 2) 4 is a schematic diagram showing the configuration of a portion of an electrolysis system 10 according to Modification 2. In the electrolysis system 10 according to Modification 2, a lithium composite oxide film is formed on the surface of a metal wire 78. Furthermore, in the electrolysis system 10 according to Modification 2, the transfer mechanism 50 and the second transfer mechanism 52 are configured to be able to transfer the lithium composite oxide film formed on the metal wire 78.

[0058] That is, the transfer mechanism 50 of this modified example has a first roller 80 and a second roller 82 instead of the supply path 56, pump 58, buffer device 60, and flow rate adjustment valve 62 of the above embodiment. The first roller 80 is a roller for feeding out the metal wire 78, and the second roller 82 is a roller for winding up the metal wire 78. The first roller 80 and the second roller 82 rotate in a predetermined direction to feed the metal wire 78 in one direction. In this way, the lithium composite oxide from which carbon dioxide has been absorbed by the absorption device 12 can be transferred to the release device 14.

[0059] The second transfer mechanism 52 of this modified example has a plurality of guide members 84 instead of the return path 64. Each guide member 84 guides the metal wire 78 taken up by the second roller 82 so as to return the metal wire 78 to the first roller 80. This makes it possible to transfer the lithium composite oxide from which carbon dioxide has been released by the release device 14 to the absorption device 12. Note that each guide member 84 may be a member that can rotate in response to the rotation of the first roller 80 and the second roller 82, or may be a member that does not rotate regardless of the rotation of the first roller 80 and the second roller 82.

[0060] In this modification, the transfer control unit 68 can drive the first roller 80 and the second roller 82 to start the transfer of the transfer mechanism 50. The transfer control unit 68 can also stop the first roller 80 and the second roller 82 to stop the transfer of the transfer mechanism 50. Furthermore, the transfer control unit 68 can control the speeds of the first roller 80 and the second roller 82 to adjust the amount of lithium composite oxide transferred to the discharging device 14.

[0061] The invention and its effects that can be understood from the above description will be described below.

[0062] (1) The present invention provides an electrolysis system (10) for electrolyzing carbon dioxide, comprising: an absorption device (12) having a reaction chamber in which a lithium composite oxide is heated to an absorption temperature that is a temperature required for absorbing the carbon dioxide, and causing the lithium composite oxide to absorb the carbon dioxide in the reaction chamber; a release device (14) that heats the lithium composite oxide in which the carbon dioxide has been absorbed to a release temperature that is a temperature required for the lithium composite oxide to release the carbon dioxide, thereby causing the carbon dioxide to be released from the lithium composite oxide; a solid oxide electrolysis stack (18) that electrolyzes the carbon dioxide released by the release device; and a transfer mechanism (50) that transfers the lithium composite oxide in which the carbon dioxide has been absorbed by the absorption device to the release device.

[0063] This allows carbon dioxide to be collected without dehydration treatment. Also, because the carbon dioxide is transported from the absorption device to the release device using the lithium composite oxide as a carbon dioxide carrier, carbon dioxide can be transported without being pressurized.

[0064] (2) The present invention may also provide an electrolysis system including a control device (54) that controls the transfer mechanism to adjust the amount of the lithium composite oxide transferred to the discharge device, thereby adjusting the amount of carbon dioxide supplied from the discharge device to the solid oxide electrolysis stack.

[0065] (3) The present invention may be an electrolysis system, wherein the control device adjusts the amount of lithium composite oxide to be transferred to the release device based on the difference between the amount of carbon dioxide transferred per unit time and the amount of carbon dioxide required per unit time by the solid oxide electrolysis stack. Transportation Efficiency can be improved.

[0066] (4) In the electrolysis system of the present invention, the release device may include a heater (36) for heating the lithium composite oxide and a temperature sensor (34) for detecting the temperature of the heater, and the control device may start the transfer mechanism when the temperature of the heater detected by the temperature sensor exceeds the release temperature. This can improve the efficiency of carbon dioxide transport.

[0067] (5) In the electrolysis system of the present invention, when the temperature of the heater becomes equal to or lower than the discharge temperature, the control device may stop the transfer of the transfer mechanism, thereby improving the efficiency of transporting carbon dioxide.

[0068] (6) The present invention provides an electrolysis system, in which the lithium composite oxide is formed into pellets. The transfer mechanism includes a supply path (56) for supplying the lithium composite oxide from the absorption device to the discharge device, a buffer device (60) interposed in the supply path and capable of temporarily storing the lithium composite oxide having absorbed carbon dioxide, and a flow control valve (62) provided in the supply path between the buffer device and the discharge device. The control device may adjust the amount of the lithium composite oxide by controlling the aperture of the flow control valve. This allows the lithium composite oxide having absorbed carbon dioxide by the absorption device to be supplied to the discharge device, and the amount of carbon dioxide can be adjusted. Furthermore, the carbon dioxide is transferred in a pellet-like state. This avoids the possibility of gas leaks, which can result in fatal accidents, as occurs when carbon dioxide gas is supplied through a gas pipe. As a result, safety is excellent.

[0069] (7) The present invention may provide an electrolysis system, wherein the transfer mechanism includes a bypass (74) branching from the supply path between the buffer device and the absorption device and joining the supply path between the buffer device and the release device, and an on-off valve (76) provided in the bypass, and the control device may adjust the amount of the lithium composite oxide by opening and closing the on-off valve. Thus, when the on-off valve of the bypass is opened, the lithium composite oxide output from the bypass is supplied to the release device in addition to the lithium composite oxide output from the buffer device. Therefore, the amount of carbon dioxide absorbed by the lithium composite oxide can be increased.

[0070] (8) The present invention may provide an electrolysis system, in which the lithium composite oxide is formed as a film on the surface of a metal wire (78), the transfer mechanism includes a first roller (80) for feeding out the metal wire and a second roller (82) for winding up the metal wire, and the control device controls the speeds of the first roller and the second roller to adjust the amount of the lithium composite oxide. This makes it possible to supply the lithium composite oxide from which carbon dioxide has been absorbed by the absorption device to the release device and to adjust the amount of carbon dioxide. Furthermore, since it is possible to prevent the lithium composite oxide from stagnating during transfer, it is possible to improve the transfer efficiency of the lithium composite oxide.

[0071] (9) The present invention may provide an electrolysis system including a second transfer mechanism (52) that transfers the lithium composite oxide from which the carbon dioxide has been released by the release device to the absorber, thereby circulating the lithium composite oxide between the absorber and the release device. [Explanation of symbols]

[0072] 10...Electrolysis system 12...Absorption device 14...Discharge device 16...Steam generator 18...Solid oxide electrolysis stack 20...Synthesis device 30, 34...Temperature sensor 32...Temperature controller 36...Heater 50...Transfer mechanism 52... Second transfer mechanism 54... Control device 56...supply path 58...pump 60...Buffer device 62...Flow rate adjusting valve 64...Return path 66...Stack control section 68...Transfer control unit 70...Power supply unit 72...Carbon monoxide sensor 74...Detour 76...Shut-off valve 78...Metal wire 80...First roller 82...Second roller 84...Guide member

Claims

1. An electrolysis system for electrolyzing carbon dioxide, comprising: an absorption device having a reaction chamber in which a lithium composite oxide is heated to an absorption temperature that is a temperature required for absorbing the carbon dioxide, and causing the lithium composite oxide to absorb the carbon dioxide in the reaction chamber; a release device that heats the lithium composite oxide having the carbon dioxide absorbed therein to a release temperature required for the lithium composite oxide to release the carbon dioxide, thereby releasing the carbon dioxide from the lithium composite oxide; a solid oxide electrolysis stack that electrolyzes the carbon dioxide released by the release device; a transfer mechanism that transfers the lithium composite oxide from which the carbon dioxide has been absorbed by the absorption device to the release device; a control device that controls the transfer mechanism to adjust the amount of the lithium composite oxide transferred to the release device; Equipped with the control device adjusts the amount of lithium composite oxide to be transferred to the release device based on a difference between the amount of carbon dioxide transferred per unit time and the amount of carbon dioxide required per unit time by the solid oxide electrolysis stack. Electrolysis system.

2. An electrolysis system for electrolyzing carbon dioxide, comprising: an absorption device having a reaction chamber in which a lithium composite oxide is heated to an absorption temperature that is a temperature required for absorbing the carbon dioxide, and causing the lithium composite oxide to absorb the carbon dioxide in the reaction chamber; a release device that heats the lithium composite oxide having the carbon dioxide absorbed therein to a release temperature required for the lithium composite oxide to release the carbon dioxide, thereby releasing the carbon dioxide from the lithium composite oxide; a solid oxide electrolysis stack that electrolyzes the carbon dioxide released by the release device; a transfer mechanism that transfers the lithium composite oxide from which the carbon dioxide has been absorbed by the absorption device to the release device; a control device that controls the transfer mechanism to adjust the amount of the lithium composite oxide transferred to the release device; Equipped with the discharging device has a heater for heating the lithium composite oxide and a temperature sensor for detecting a temperature of the heater, When the temperature of the heater detected by the temperature sensor exceeds the discharge temperature, the control device starts the transfer of the transfer mechanism. Electrolysis system.

3. 3. The electrolysis system according to claim 2, When the temperature of the heater becomes equal to or lower than the discharge temperature, the control device stops the transfer of the transfer mechanism. Electrolysis system.

4. The electrolysis system according to any one of claims 1 to 3, The lithium composite oxide is formed into a pellet shape, The transfer mechanism includes: a supply path for supplying the lithium composite oxide from the absorption device to the release device; a buffer device interposed in the supply path and capable of temporarily storing the lithium composite oxide in which the carbon dioxide has been absorbed; a flow rate adjusting valve provided in the supply path between the buffer device and the discharge device; Including, the control device controls the opening degree of the flow rate adjustment valve to adjust the amount of the lithium composite oxide. Electrolysis system.

5. 5. The electrolysis system according to claim 4, The transfer mechanism includes: a bypass path branching off from the supply path between the buffer device and the absorption device and joining the supply path between the buffer device and the discharge device; an on-off valve provided in the bypass; Including, the control device opens and closes the on-off valve to adjust the amount of the lithium composite oxide. Electrolysis system.

6. The electrolysis system according to any one of claims 1 to 3, The lithium composite oxide is formed as a film on the surface of a metal wire, The transfer mechanism includes: a first roller for feeding the metal wire; a second roller for winding the metal wire; Including, the control device controls the speeds of the first roller and the second roller to adjust the amount of the lithium composite oxide. Electrolysis system.

7. The electrolysis system according to any one of claims 1 to 6, a second transfer mechanism that transfers the lithium composite oxide from which the carbon dioxide has been released by the release device to the absorption device; Electrolysis system.

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