Chemical looping combustion system

Abstract

A chemical looping combustion system is provided with: an oxidation tower that oxidizes metal particles; and a fuel tower in which the oxidized metal particles are supplied from the oxidation tower while hydrogen gas and a carbon-containing compound are supplied as fuel, the metal particles are reduced using the fuel, and a gas containing carbon dioxide is discharged.

Description

Technical Field

[0001] The present invention relates to a chemical looping combustion system. Background Art

[0002] Chemical looping combustion systems capable of substantially separating carbon dioxide are known (see, for example, Patent Document 1 and Non-Patent Document 1). In the system described in Patent Document 1, a metal serving as a solid oxygen carrier reacts with oxygen in the air in an air reactor to be oxidized. The oxidized metal is then reduced by fuel in a fuel reactor and then oxidized again in the air reactor. An oxidation catalyst located downstream of the fuel reactor combusts unburned carbon monoxide discharged from the fuel reactor, converting it into carbon dioxide.

[0003] In the technology described in Non-Patent Document 1, the metal reduction reaction occurring in the fuel tower is endothermic, and the heat lost by the endothermic reaction is replenished by a heater external to the fuel tower. Furthermore, flow-sealed valves are located between the oxidation tower (where the metal is oxidized) and the fuel tower, and between the fuel tower and the oxidation tower. Water vapor is supplied into the flow-sealed valves to fluidize the metal particles.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application No. 2013-522149

[0007] Non-patent literature

[0008] Non-patent literature 1: Carl Linderholm, et al. “160h of chemical-loopingcombustion in a 10kW reactor system with a NiO-based oxygen carrier.” International Journal of Greenhouse Gas Control Volume 2, issue 4, October2008, Pages 520-530 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] The technology described in Non-Patent Document 1 utilizes external heaters to compensate for heat lost due to the endothermic reaction within the fuel reactor, resulting in significant heat dissipation losses. Furthermore, generating water vapor to supply the flow-tight valve requires energy. Therefore, further improvements in the overall energy efficiency of the chemical looping combustion system are desired. It should be noted that Patent Document 1 does not mention the replacement of heat lost within the fuel reactor or the use of a flow-tight valve.

[0011] The present invention has been made to solve at least a part of the above-mentioned problems, and an object thereof is to improve the energy efficiency of the entire chemical looping combustion system.

[0012] Methods used to solve problems

[0013] The present invention has been made to solve at least a part of the above-mentioned problems, and can be implemented as follows.

[0014] (1) According to one embodiment of the present invention, a chemical looping combustion system is provided. The chemical looping combustion system includes: an oxidation tower that oxidizes metal particles; and a fuel tower that is supplied with hydrogen and a carbon-containing compound as fuel and is supplied with the oxidized metal particles from the oxidation tower, and reduces the metal particles using the fuel.

[0015] According to this configuration, within the fuel tower, the carbon-containing compound serving as fuel reduces the oxidized metal particles, thereby causing an endothermic reaction. On the other hand, in addition to the carbon-containing compound, the hydrogen gas supplied to the fuel tower reduces the oxidized metal particles, thereby causing a weakly exothermic reaction. Therefore, all or part of the heat lost in the endothermic reaction caused by the carbon-containing compound reducing the metal particles can be compensated by the heat from the weakly exothermic reaction caused by the hydrogen gas reducing the metal particles. In this configuration, the interior of the fuel tower is directly heated by the weakly exothermic reaction, so that, for example, compared to a case where the interior of the fuel tower is heated from the outside using a heater, etc., heat loss is reduced. As a result, the overall energy efficiency of the system is improved compared to a case where only the carbon-containing compound is supplied to the fuel tower as fuel.

[0016] (2) In the chemical link combustion system of the above-mentioned method, it can also be provided with: a temperature acquisition unit, which acquires the temperature in the above-mentioned fuel tower; and a control unit, which uses the difference between the temperature acquired by the above-mentioned temperature acquisition unit and the specified temperature to determine the flow rate of hydrogen and carbon-containing compounds supplied to the above-mentioned fuel tower.

[0017] With this configuration, the temperature within the fuel tower is acquired. The flow rate ratio of hydrogen gas and the carbon-containing compound serving as fuel is controlled based on the difference between the temperature within the fuel tower and a predetermined temperature. Thus, heating within the fuel tower, which utilizes the weakly exothermic reaction caused by the reduction of metal particles by hydrogen, is controlled based on the temperature within the fuel tower, and the amount of reduced metal particles is also controlled. As a result, oxidized metal particles can be reduced while maintaining the temperature within the fuel tower at a desired level.

[0018] (3) The chemical looping combustion system of the above aspect may further include a water electrolysis unit that electrolyzes water to generate hydrogen and oxygen, and the water electrolysis unit supplies the generated hydrogen and oxygen to the fuel tower.

[0019] According to this configuration, the hydrogen and oxygen generated by the water electrolysis unit are supplied to the fuel tower. The oxygen flowing into the fuel tower reoxidizes the metal particles reduced by the fuel within the fuel tower. The exothermic reaction caused by the oxygen oxidizing the metal particles heats the interior of the fuel tower. Unlike oxygen in air, the oxygen generated by water electrolysis does not contain impurities such as nitrogen, allowing high-purity carbon dioxide to be recovered from the fuel tower. Furthermore, since oxygen is a byproduct of the hydrogen generated by water electrolysis, the overall energy efficiency of the system is improved.

[0020] (4) In the chemical loop combustion system of the above-mentioned method, a flow sealing valve can also be provided. The flow sealing valve is arranged on the downstream side of the above-mentioned oxidation tower and the upstream side of the above-mentioned fuel tower to inhibit the gas from flowing from the above-mentioned oxidation tower into the above-mentioned fuel tower. The above-mentioned water electrolysis unit supplies the generated hydrogen to the above-mentioned fuel tower and supplies the generated oxygen to the above-mentioned flow sealing valve instead of supplying it to the above-mentioned fuel tower.

[0021] According to this configuration, oxygen generated as a by-product of hydrogen by the water electrolysis unit is supplied into the flow sealing valve. In the flow sealing valve, in order to promote the flow of metal particles and prevent the metal particles from condensing and adhering to each other, it is preferably supplied with gas. Furthermore, the gas supplied into the flow sealing valve is likely to flow into the fuel tower, and therefore preferably does not contain impurities such as nitrogen. The oxygen supplied into the flow sealing valve suppresses the inflow of impurities such as nitrogen that are about to flow into the flow sealing valve from the oxidation tower. In addition, by supplying oxygen into the flow sealing valve, it is not necessary to supply other gases (such as water vapor) to prevent the inflow of impurities. That is, the oxygen supplied into the flow sealing valve is a by-product of hydrogen generated by water electrolysis, and the metal particles are reoxidized in the fuel tower to heat the inside of the fuel tower, so the overall energy efficiency of the system of this configuration is improved.

[0022] (5) In the chemical chain combustion system of the above-mentioned method, a hydrogen tank may also be provided, which stores the hydrogen generated by the above-mentioned water electrolysis unit. Regarding the above-mentioned control unit, when the above-mentioned water electrolysis unit is used to generate hydrogen and oxygen, the generated oxygen is supplied to the above-mentioned fuel tower, and at least a part of the generated hydrogen is stored in the above-mentioned hydrogen tank. When the above-mentioned water electrolysis unit is not used to generate hydrogen and oxygen, the hydrogen stored in the above-mentioned hydrogen tank is supplied to the above-mentioned fuel tower.

[0023] According to this configuration, when the power supply from the power source supplying electricity to the water electrolysis unit for water electrolysis fluctuates, the supply of hydrogen and oxygen from the water electrolysis unit is controlled based on the power supply. When power is supplied and the water electrolysis unit generates hydrogen and oxygen, the generated hydrogen is stored in the hydrogen tank. Meanwhile, the generated oxygen is supplied to the fuel tower, oxidizing the metal particles and generating an exothermic reaction. As a result, the heat lost due to the reduction reaction of carbon-containing compounds in the fuel tower is replenished through the exothermic reaction. When power is not supplied and the water electrolysis unit is not performing water electrolysis, the hydrogen stored in the hydrogen tank is supplied to the fuel tower, thereby replenishing the heat lost due to the reduction reaction of carbon-containing compounds through a weak exothermic reaction. In other words, according to this configuration, oxygen, a byproduct of water electrolysis, is effectively utilized based on the amount of power supplied to the water electrolysis unit, and when power is not supplied, the hydrogen stored in the hydrogen tank is used to heat the fuel tower. As a result, the overall energy efficiency of the system is improved.

[0024] It should be noted that the present invention can be implemented in various ways, for example, as a chemical chain combustion system, a chemical chain combustion device, a chemical chain combustion method and a system having these devices, a computer program for executing these devices, a server device for distributing the computer program, a non-temporary storage medium storing the computer program, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic block diagram of a chemical looping combustion system as one embodiment of the present invention.

[0026] Figure 2 This diagram illustrates the principle of chemical looping combustion.

[0027] Figure 3 is a schematic block diagram of a chemical looping combustion system of a comparative example.

[0028] Figure 4 It is a schematic block diagram of a chemical looping combustion system according to a second embodiment.

[0029] Figure 5 It is a schematic block diagram of a chemical looping combustion system according to a third embodiment.

[0030] Figure 6 It is a schematic block diagram of a chemical looping combustion system according to a fourth embodiment.

[0031] Figure 7 This is a flowchart of a fuel flow rate control method according to a fourth embodiment.

[0032] Figure 8 It is a schematic block diagram of a chemical looping combustion system according to a fifth embodiment.

[0033] Figure 9 This is a flowchart of a fuel flow rate control method according to the fifth embodiment.

[0034] Figure 10 It is a schematic block diagram of a chemical looping combustion system according to a sixth embodiment. DETAILED DESCRIPTION

[0035] <First embodiment>

[0036] Figure 1 This is a schematic block diagram of a chemical looping combustion system (hereinafter also referred to as the "combustion system") 100, which is one embodiment of the present invention. In combustion system 100, an air column-side flow seal valve portion (flow seal valve) 60, disposed between an oxidation column 10, which oxidizes metal particles mg, and a fuel column 20, which reduces metal particles mg, is used to suppress nitrogen flow from oxidation column 10 into fuel column 20, thereby enabling the recovery of high-purity carbon dioxide (CO2) from fuel column 20. In conventional chemical looping combustion systems, the temperature within fuel column 20 decreases due to the endothermic reaction caused by the reduction of metal particles mg with hydrocarbons (carbon-containing compounds) in fuel column 20, and therefore the interior of fuel column 20 is heated by an external heater. In contrast, in this embodiment, hydrogen (H2) is supplied to fuel column 20 as a fuel in addition to hydrocarbons. The reduction reaction of H2 with metal particles mg is a weakly exothermic reaction, so this reaction can suppress the temperature drop within fuel column 20. The weakly exothermic reaction using H2 directly heats the interior of the fuel tower 20, resulting in less heat loss than with an external heater. Consequently, the overall energy efficiency of the combustion system 100 of this embodiment can be improved.

[0037] In the combustion system 100, oxidation in the oxidation tower 10 and reduction in the fuel tower 20 are repeated, and the metal particles mg are circulated by transporting oxygen (O2) in the air from the oxidation tower 10 to the fuel tower 20. In this embodiment, an example of the oxidation reaction using Fe3O4 as the metal particles mg is described. The particle size of the metal particles mg is greater than 50 mm and less than 250 mm. Figure 1As shown, the combustion system 100 of the first embodiment includes an oxidation tower 10 , a fuel tower 20 , an air tower side flow sealing valve portion 60 , a fuel tower side flow sealing valve portion 70 , a cyclone separator 15 , and a dehydrator 40 .

[0038] Oxidation tower 10 uses air containing O₂ to oxidize Fe₃O₄ by reacting as shown in the following equation (1). The oxidation reaction in equation (1) is exothermic. Therefore, the reaction in equation (1) generates heat, heating the gas within oxidation tower 10 and bringing the interior of oxidation tower 10 to approximately 1000 degrees Celsius (°C).

[0039]

[0040] like Figure 1 As shown, the oxidation tower 10 has a cylindrical shape extending in the vertical direction. A seal 10S is provided at the vertically lower part of the oxidation tower 10. The seal 10S is a component with a plurality of fine holes. With the seal 10S, air supplied from the vertically lower part of the oxidation tower 10 flows into the oxidation tower 10, and the metal particles mg are transported vertically upward. On the other hand, since the size of the holes provided in the seal 10S is smaller than the metal particles mg, the metal particles mg are prevented from leaking out of the oxidation tower 10 through the seal 10S. It should be noted that the gas flow rate toward the vertically upper part of the oxidation tower 10 is set to a terminal velocity at which gravity and the resistance of the airflow are balanced, or a velocity higher than the terminal velocity.

[0041] The metal particles mg oxidized in the oxidation tower 10 flow into the cyclone separator 15 connected via a pipeline. The cyclone separator 15 uses centrifugal force to separate the metal particles mg from the heated gas. Figure 1 As shown, the gas heated in the oxidation tower 10 flows out from the vertical upper part of the cyclone separator 15 and is supplied to a heat utilization site. As for the composition of the gas supplied to the heat utilization site, the gas is mostly composed of N2 because of the reduction of O2 due to the oxidation of the metal particles mg in the oxidation tower 10. Figure 1 As shown, the metal particles mg separated from the gas in the cyclone separator 15 pass through a duct extending vertically downward provided in the center portion of the cyclone separator 15 and move toward the air tower side flow seal valve portion 60 .

[0042] like Figure 1 As shown, the air tower side flow sealing valve portion 60 is arranged on the downstream side of the oxidation tower 10 and the upstream side of the fuel tower 20. A seal 60S is provided vertically below the air tower side flow sealing valve portion 60. The seal 60S is a member having a plurality of pores. The pores formed in the seal 60S are smaller than the particle size of the metal particles mg. Therefore, as shown in FIG. Figure 1As shown, a particle layer (hatched portion) composed of a plurality of metal particles mg is formed on the upper surface of the seal 60S. Water vapor is used here because even if water vapor flows into the fuel tower 20, it can be removed by the dehydrator 40.

[0043] Water vapor is supplied to the air tower flow seal valve section 60 from vertically below the seal 60S. The supplied water vapor flows through the seal 60S and into the fuel tower 20, which is connected to the downstream side of the air tower flow seal valve section 60. Since water vapor is supplied from below the seal 60S into the air tower flow seal valve section 60, the gas primarily composed of N₂ is prevented from passing through the particle layer and flowing from the cyclone separator 15 into the fuel tower 20.

[0044] A fluidized bed is disposed in the pipe connecting the air tower side flow seal valve section 60 and the fuel tower 20. The fluidized bed flows from the air tower side flow seal valve section 60 to the fuel tower 20. The flow of the fluidized bed causes the metal particles mg discharged from the cylindrical air tower side flow seal valve section 60 to move toward the fuel tower 20.

[0045] In this embodiment, hydrogen (H2) and methane (CH4) are supplied as fuel to the fuel tower 20. Oxidized metal particles mg are supplied from the oxidation tower 10, and a gas containing water vapor is supplied to the air tower flow seal valve 60. The fuel tower 20 reduces the metal particles mg using the H2 and CH4. A mixed gas containing CO2, generated by the reduction reaction between the CH4 and the metal particles mg, is discharged.

[0046] like Figure 1 As shown, the fuel tower 20 has a cylindrical shape extending in the vertical direction. A seal 20S is provided vertically below the fuel tower 20. The seal 20S is a member having a plurality of pores. Gas fuel is supplied to the fuel tower 20 from below the seal 20S. It should be noted that the gas flow rate within the fuel tower 20 is set to a speed slower than the terminal velocity and is controlled so that the metal particles mg do not fly out of the fuel tower 20.

[0047] In the fuel tower 20 supplied with CH₄ as fuel, Fe₂O₃, the metal particles mg oxidized in the oxidation tower 10 as shown in the above formula (1), is reduced by CH₄ to Fe₃O₄ as shown in the following formula (2), generating CO₂. The reduction reaction shown in the following formula (3) is an endothermic reaction.

[0048]

[0049] Furthermore, within the fuel tower 20, where H₂ is supplied as fuel along with CH₄, the oxidized metal particles mg, Fe₂O₃, are reduced by H₂ to Fe₃O₄ as shown in the following equation (3). The reduction reaction shown in the following equation (3) is a weakly exothermic reaction. Therefore, when the weakly exothermic reaction in the following equation (3) occurs, the interior of the fuel tower 20 is heated.

[0050]

[0051] Taking the sum of the oxidation reaction within oxidation tower 10 represented by equation (1) above and the reduction reaction of CH₄ within fuel tower 20 represented by equation (2) above, the reaction between oxidation tower 10 and fuel tower 20, including the reduction reaction of CH₄ within fuel tower 20, is the same as the combustion of CH₄ represented by equation (4) below. That is, the total amount of heat generated by the oxidation of metal particles mg and the reduction of metal particles mg by CH₄ (the sum of heat released by oxidation tower 10 and heat absorbed by fuel tower 20) is the same as that of the combustion of CH₄.

[0052]

[0053] like Figure 1 As shown, the mixed gas containing CO2 generated by the reduction reaction in the fuel tower 20 flows out from the vertical upper portion of the fuel tower 20 and is sent to the dehydrator 40. The high-purity CO2 from which water vapor has been removed by the dehydrator 40 is sent to a CO2 utilization site. Examples of CO2 utilization sites include storage tanks for liquefied or pressurized CO2.

[0054] like Figure 1 As shown, the metal particles mg reduced by the reduction reaction in the fuel tower 20 pass through a pipe extending vertically downward provided in the center portion of the fuel tower 20 and move toward the fuel tower side flow sealing valve portion 70 .

[0055] The fuel tower-side flow seal valve section 70, to which metal particles mg are supplied from within the fuel tower 20, is located downstream of the fuel tower 20 and upstream of the oxidation tower 10. The fuel tower-side flow seal valve section 70 has the same structure as the air tower-side flow seal valve section 60. A seal 70S is provided vertically below the fuel tower-side flow seal valve section 70. The seal 70S is a member having multiple pores. Water vapor is supplied vertically below the seal 70S to the fuel tower-side flow seal valve section 70. The supplied water vapor flows through the seal 70S into the oxidation tower 10, which is connected to the downstream side of the fuel tower-side flow seal valve section 70. A fluidized bed is provided in the pipe connecting the fuel tower-side flow seal valve section 70 and the oxidation tower 10, flowing from the fuel tower-side flow seal valve section 70 to the oxidation tower 10. The flow of the fluidized bed causes the metal particles mg within the cylindrical fuel tower-side flow seal valve section 70 to move toward the oxidation tower 10. As described above, the metal particles mg are oxidized in the oxidation tower 10 , reduced in the fuel tower 20 , and circulate between the oxidation tower 10 and the fuel tower 20 .

[0056] Figure 2 This is a diagram illustrating the principle of chemical looping combustion. Figure 2 A schematic block diagram of the combustion system 100 is shown in FIG. Figure 2 In FIG, the metal atom (or molecule) used as the metal particle mg is represented by Me.

[0057] In the oxidation tower 10, air is supplied as an oxidizing gas, and the reaction heat generated by the oxidation reaction of the metal particles mg is supplied to a heat utilization site in the form of high-temperature N2 that does not contain CO2. In the fuel tower 20, the oxidized metal particles mg are reduced using a fuel such as H2 and CH4, and the resulting mixed gas containing CO2 generated by the reduction reaction is supplied to the dehydrator 40. It should be noted that no CO2 is produced when the metal particles mg are reduced using H2. In the dehydrator 40, H2O is removed from the mixed gas, and the resulting mixed gas containing high-purity CO2 is supplied to a CO2 utilization site.

[0058] Comparative Example

[0059] Figure 3 FIG. 1 is a schematic block diagram of a chemical looping combustion system (combustion system) 100x of a comparative example. Figure 1 The combustion system 100 shown is compared to the Figure 3In the illustrated comparative example combustion system 100x, CH4 is supplied as fuel to the fuel tower 20x instead of H2. Therefore, no reduction reaction of the metal particles mg by H2 occurs within the fuel tower 20x of the comparative example, that is, no weakly exothermic reaction between H2 and the metal particles mg occurs. In the comparative example, since the interior of the fuel tower 20 is not heated by the weakly exothermic reaction, the combustion system 100x includes a heater 25 for heating the interior of the fuel tower 20.

[0060] In contrast, in the combustion system 100 of this embodiment, hydrogen (H2) and methane (CH4) are supplied as fuel to the fuel tower 20. In the fuel tower 20, the H2 and CH4 serving as fuels reduce the oxidized metal particles mg from the oxidation tower 10. In this embodiment, CH4 reduces the oxidized metal particles mg within the fuel tower 20, resulting in an endothermic reaction. Meanwhile, H2, supplied to the fuel tower 20 in addition to CH4, also reduces the oxidized metal particles mg, resulting in a weakly exothermic reaction. Therefore, the heat from the weakly exothermic reaction caused by H2 reducing the metal particles mg can compensate for all or part of the heat lost in the endothermic reaction caused by CH4 reducing the metal particles mg. Because the interior of the fuel tower 20 is directly heated by the weakly exothermic reaction, heat loss in this embodiment is reduced compared to heating using an external heater 25, as in the comparative example. As a result, the overall energy efficiency of the combustion system 100 is improved compared to a case where only CH4 is supplied to the fuel tower 20 as fuel.

[0061] <Second embodiment>

[0062] Figure 4 FIG. 1 is a schematic block diagram of a chemical looping combustion system (combustion system) 100a according to a second embodiment. Figure 4 As shown, the combustion system 100a of the second embodiment may further include a water electrolysis device (water electrolysis unit) 30 that electrolyzes water to generate H2 and O2. The combustion system 100a of the second embodiment differs from the combustion system 100 of the first embodiment in that the H2 supplied to the fuel tower 20 is H2 generated by water electrolysis in the water electrolysis device 30, and that the O2 generated by water electrolysis is supplied to the fuel tower 20. In the second embodiment, the configurations that differ from the first embodiment are described, and descriptions of the same configurations are omitted.

[0063] In the second embodiment, by supplying O₂ into the fuel tower 20, an exothermic reaction occurs, as shown in the above formula (1), in which the reduced metal particles mg are reoxidized within the fuel tower 20. The exothermic reaction caused by oxidation heats the interior of the fuel tower 20. When O₂ generated by water electrolysis is supplied to the fuel tower, the supply of H₂ used to heat the interior of the fuel tower 20 can be reduced. Unlike air, the O₂ supplied to the fuel tower 20 does not contain N₂. Therefore, even when O₂ generated by water electrolysis is supplied to the fuel tower 20, a decrease in the CO₂ concentration in the mixed gas discharged from the fuel tower 20 can be suppressed.

[0064] As described above, the water electrolysis device 30 of the second embodiment electrolyzes water to generate H2 and O2. The generated H2 and O2 are supplied to the fuel tower 20. In the second embodiment, the O2 flowing into the fuel tower 20 is reoxidized within the fuel tower 20 by the metal particles mg reduced by CH4 or H2. The exothermic reaction caused by the oxidation of the metal particles mg by O2 heats the interior of the fuel tower 20. Unlike O2 in air, the O2 generated by water electrolysis does not contain impurities such as N2, making it possible to recover high-purity CO2 from the fuel tower 20. Furthermore, since O2 is a byproduct of the H2 generated by water electrolysis, the overall energy efficiency of the combustion system 100a is improved.

[0065] <Third embodiment>

[0066] Figure 5 This is a schematic block diagram of a chemical looping combustion system (combustion system) 100b according to the third embodiment. Compared to the combustion system 100a according to the second embodiment, the combustion system 100b according to the third embodiment differs in that the O2 generated by the water electrolysis device 30b is supplied to the air column flow seal valve 60 instead of being supplied to the fuel column 20. In the third embodiment, the configurations that differ from the second embodiment are described, and descriptions of the same configurations are omitted.

[0067] In the third embodiment, O2 generated by the water electrolysis device 30b is supplied from below the seal 60S of the air column-side flow seal valve unit 60, along with water vapor. When O2 is supplied to the air column-side flow seal valve unit 60, a portion of the O2 flows into the fuel column 20, while the remainder flows into the cyclone separator 15. Similar to the O2 supplied to the fuel column 20 in the second embodiment, the O2 flowing into the fuel column 20 reacts with the reduced metal particles mg within the fuel column 20. The heat generated by the oxidation reaction of O2 with the metal particles mg heats the interior of the fuel column 20.

[0068] As described above, in the third embodiment, the O2 generated by the water electrolysis device 30b is supplied to the air column flow seal valve section 60 instead of to the fuel column 20. To promote the flow of the metal particles mg and prevent coagulation and adhesion of the metal particles mg, it is preferable to supply a gas such as water vapor to the air column flow seal valve section 60. Furthermore, the gas supplied to the air column flow seal valve section 60 may flow into the fuel column 20, so it preferably does not contain impurities such as N2. The O2 supplied to the air column flow seal valve section 60 suppresses the inflow of impurities such as N2 that attempt to flow from the oxidation column 10 into the air column flow seal valve section 60. Furthermore, supplying O2 to the air column flow seal valve section 60 reduces the flow rate of water vapor required to prevent the inflow of impurities. Specifically, the O2 supplied to the air column flow seal valve section 60, a byproduct of the H2 generated by water electrolysis, reoxidizes the metal particles mg within the fuel column 20, heating the interior of the fuel column 20. This improves the overall energy efficiency of the combustion system 100b.

[0069] <Fourth embodiment>

[0070] Figure 6 This is a schematic block diagram of a chemical looping combustion system (combustion system) 100c according to a fourth embodiment. Compared to the combustion system 100 according to the first embodiment, the fourth embodiment's combustion system 100c significantly differs from the combustion system 100 according to the first embodiment in controlling the flow rates of CH4 and H2, which serve as fuels supplied to the fuel tower 20. In the fourth embodiment, only the components and controls that differ from those of the first embodiment are described, and descriptions of the same components are omitted.

[0071] like Figure 6 As shown, the combustion system 100c of the fourth embodiment further includes a temperature T in the fuel tower 20. FR The temperature sensor (temperature acquisition unit) 26 for detection uses the detected temperature T in the fuel tower 20. FR The controller 50 controls the flow rates of CH 4 and H 2 supplied to the fuel tower 20 . The temperature sensor 26 of this embodiment is a thermocouple inserted into the fuel tower 20 .

[0072] Although Figure 6 Although not shown in the figure, the combustion system 100c includes valves for controlling the flow rates of CH4 and H2 supplied to the fuel tower 20. The control unit 50 controls the flow rate of CH4 and H2 supplied to the fuel tower 20 according to the temperature T in the fuel tower 20. FR and the target temperature T as the specified temperature FR_tar The flow rate Q of H2 supplied to the fuel tower 20 is determined by the difference FR_H2 and CH4 flow Q FR_HC .

[0073] The control unit 50 of this embodiment uses the temperature T in the fuel tower 20 detected by the temperature sensor 26 to determine the temperature. FR Substituting into the following equation (5) determines the flow rate Q of H2 supplied to the fuel tower 20 after Δt seconds from the current time t FR_H2 It should be noted that k1 in formula (5) is a positive constant and can be set arbitrarily by the user.

[0074]

[0075] Here, both CH4 and H2 as fuel react with the oxidized metal particles mg. Therefore, the controller 50 of this embodiment makes the flow rate Q of H2 FR_H2 In the case of increasing the other CH4 flow Q FR_HC On the other hand, the control unit 50 makes the flow rate Q of H2 FR_H2 When the other CH4 flow Q is reduced FR_HC Here, the CH4 flow rate Q after Δt seconds from time t is FR_HC (t+Δt) is expressed as the following equation (6).

[0076]

[0077] a1: The amount of metal particles that can be reduced by 1 mol of CH4 (mol(metal) / mol(CH4))

[0078] b1: The amount of metal particles that can be reduced by 1 mol of H2 (mol(metal) / mol(H2))

[0079] In this embodiment, since the reduction reaction of the above formulas (2) and (3) occurs, in the above formula (5), a1=12 and b1=3.

[0080] Figure 7 FIG. 4 is a flow chart of a fuel flow control method according to a fourth embodiment. Figure 7 In the flow control flow shown, first, the control of the combustion system 100c is started (step S1). The control unit 50 obtains the temperature T in the fuel tower 20 via the temperature sensor 26. FR (Step S2). The control unit 50 sets the temperature T FR Substituting into the above formula (5) to determine the flow rate Q of H2 supplied to the fuel tower 20 FR_H2 (Step S3) The determined flow rate Q is supplied to the fuel tower 20. FR_H2 H2.

[0081] The control unit 50 determines the flow rate Q of H2 by FR_H2Substituting into the above formula (6), the flow rate of CH4 supplied to the fuel tower 20 is determined (step S4). The determined flow rate Q is supplied to the fuel tower 20. FR_HC The control unit 50 determines the flow rate Q of CH4 from the FR_HC The control unit 50 starts to check whether the predetermined time Δt has passed (step S5 ). If it is determined that the predetermined time Δt has not passed (step S5 : NO), the control unit 50 waits until the predetermined time Δt has passed.

[0082] If it is determined that the prescribed time Δt has passed (step S5: Yes), the control unit 50 determines whether to terminate the flow control process (step S6). The control unit 50 determines whether to terminate the flow control process, for example, by determining whether an end operation has been received from the user. If it is determined that the flow control process is not to be terminated (step S6: No), the process after step S2 is repeated. If it is determined that the flow control process is to be terminated (step S6: Yes), the flow control process is terminated. It should be noted that the determination of whether to terminate the flow control process can also be inserted into other processes.

[0083] As described above, the control unit 50 of this embodiment uses the temperature T in the fuel tower 20 detected by the temperature sensor 26. FR With the target temperature T FR_tar The difference between the CH4 flow rate Q supplied to the fuel tower 20 is determined by FR_HC and H2 flow rate Q FR_H2 According to the temperature T in the fuel tower 20 FR To control the flow ratio of H2 and CH4 in the fuel. FR The heating inside the fuel tower 20 is controlled by using the weak exothermic reaction caused by the reduction of the metal particles mg by H2, and the amount of the reduced metal particles mg is controlled. As a result, the temperature inside the fuel tower 20 can be controlled to be close to the target temperature T FR_tar On the basis of reducing the oxidized metal particles mg.

[0084] <Modification of the Fourth Embodiment>

[0085] In the fourth embodiment, the flow rate Q of H2 supplied to the fuel tower 20 is FR_H2 and CH4 flow Q FR_HC The method of determining is an example and can be modified. For example, the control unit 50 can supply the fuel tower 20 with the flow rate Q of H2 determined by the following equations (7) and (8): FR_H2 and CH4 flow Q FR_HC It should be noted that k2, b2 in formula (7) and Q in formula (8) FR_HC_0 is an arbitrarily set constant.

[0086]

[0087]

[0088] <Fifth embodiment>

[0089] Figure 8 This is a schematic block diagram of a chemical looping combustion system (combustion system) 100d according to the fifth embodiment. The fifth embodiment's combustion system 100d differs significantly from the second embodiment's combustion system 100a in that the flow rates of H2 and O2 generated by the water electrolysis device 30d fluctuate, and the controller 50d controls the flow rate of gas supplied to the fuel tower 20 based on the fluctuating H2 and O2 flow rates. In the fifth embodiment, only the components and controls that differ from the second embodiment are described, and descriptions of the same components are omitted.

[0090] like Figure 8 As shown, the combustion system 100d further includes a control unit 50d, a hydrogen tank 35 capable of storing H2 generated by the water electrolysis device 30d, and a variable power supply device (power supply device) PW that supplies power to the water electrolysis device 30d for water electrolysis. The power supply device PW is a so-called solar cell. Therefore, the power supply device PW generates solar power during the day and supplies power to the water electrolysis device 30d, but does not supply power to the water electrolysis device 30d at night.

[0091] The control unit 50d of this embodiment detects whether or not power is supplied from the power supply device PW to the water electrolysis device 30d. Figure 8 The flow rate Q of CH4 supplied to the fuel tower 20 is controlled by opening and closing various valves not shown in the figure. FR_HC 、O2 flow Q FR_O2 and the flow rate Q of H2 supplied from the hydrogen tank 35 to the fuel tower 20 FR_H2 When power is supplied from the power supply device PW and the water electrolysis device 30d performs water electrolysis to generate H2 and O2, the control unit 50d supplies the generated O2 together with CH4 to the fuel tower 20 and stores the generated H2 in the hydrogen tank 35. On the other hand, when power is not supplied from the power supply device PW and the water electrolysis device 30d does not perform water electrolysis, the control unit 50d supplies the H2 stored in the hydrogen tank 35 together with CH4 to the fuel tower 20. It should be noted that some or all of the H2 generated during water electrolysis may also be supplied to the fuel tower 20.

[0092] The control unit 50d of this embodiment determines the flow rate Q of O2 supplied to the fuel tower 20 by the following formula (9): FR_O2 It should be noted that Q in formula (9) O2_WLis the amount of O 2 generated by the water electrolysis device 30d at time t. In addition, k3 and b3 are constants that can be arbitrarily set by the user.

[0093]

[0094] The O2 supplied to the fuel tower 20 reoxidizes the metal particles mg reduced by the fuel. Therefore, additional fuel is required to reduce the reoxidized metal particles mg. In this embodiment, the control unit 50d supplies a flow rate Q determined by the following formula (10): FR_H2 H2 is used as additional fuel.

[0095]

[0096] c: The amount of O2 in moles required to completely burn 1 mol of H2 (mol(O2) / mol(H2))

[0097] The chemical formula for the combustion of H2 is represented by the following formula (11), so c in formula (10) is 0.5.

[0098]

[0099] In the above equation (9), when the following relational equation (12) holds, the flow rate Q generated by water electrolysis is supplied to the fuel tower 20. FR_O2 The O2 generated by water electrolysis cannot sufficiently heat the inside of the fuel tower 20. In this case, the fuel tower 20 needs to be heated by H2 generated by water electrolysis. In this case, the control unit 50d determines the flow rate Q of H2 supplied to the fuel tower 20 by using the following formula (13) instead of the above formula (10): FR_H2 Furthermore, the control unit 50d determines the flow rate Q of CH4 supplied to the fuel tower 20 using the following formula (14): FR_HC k4 and b4 are constants that can be set arbitrarily by the user.

[0100]

[0101]

[0102]

[0103] Figure 9 FIG. 1 is a flow chart of a fuel flow control method according to a fifth embodiment. Figure 9 In the flow control flow shown, first, the control of the combustion system 100d is started (step S11). The control unit 50d obtains the temperature T in the fuel tower 20 via the temperature sensor 26. FR(Step S12). The control unit 50d determines whether power is being supplied from the power supply device PW to the water electrolysis device 30d (Step S13). If it is determined that power is not being supplied to the water electrolysis device 30d (Step S13: No), the control unit 50d controls the flow rate Q of O2 supplied to the fuel tower 20. FR_O2 is determined to be zero (step S15A). In this case, the control unit 50d controls the temperature T FR Substituting into the above formula (5) to determine the flow rate Q of H2 supplied to the fuel tower 20 FR_H2 (Step S16A) The determined flow rate Q is supplied to the fuel tower 20. FR_H2 In addition, the control unit 50d determines the flow rate Q of H2 FR_H2 Substituting into the above formula (6), the flow rate of CH4 supplied to the fuel tower 20 is determined (step S17A). The determined flow rate Q is supplied to the fuel tower 20. FR_HC of CH4.

[0104] In the process of step S13, if it is determined that power is being supplied to the water electrolysis device 30d (step S13: Yes), the control unit 50d determines that only the flow rate Q of O2 generated by water electrolysis is supplied to the fuel tower 20. FR_O2 Whether the fuel tower 20 can be heated sufficiently (step S14). In this embodiment, the control unit 50d uses the flow rate Q of O2 currently generated by water electrolysis as shown in the left side of the above formula (12). O2_WL That is, it is determined whether sufficient O2 is generated by water electrolysis.

[0105] In the process of step S14, if it is determined that sufficient O2 is generated by water electrolysis and the interior of the fuel tower 20 can be sufficiently heated (step S14: Yes), the control unit 50d sets the flow rate Q of CH4 to FR_HC Determine the flow rate Q as a constant FR_HC_0 (Step S15B) The determined flow rate Q is supplied to the fuel tower 20. FR_HC_0 The control unit 50d uses the above formula (9) to determine the flow rate Q of O2 supplied to the fuel tower 20. FR_O2 (Step S16B) The determined flow rate Q is supplied to the fuel tower 20. FR_O2 The control unit 50d sets the flow rate Q determined by the above formula (9) FR_O2 Substituting into the above formula (10) to determine the flow rate Q of H2 supplied to the fuel tower 20 FR_H2 (Step S17B) The determined flow rate Q is supplied to the fuel tower. FR_H2 H2.

[0106] In the process of step S14, if it is determined that sufficient O2 is not generated by water electrolysis and the interior of the fuel tower 20 cannot be heated sufficiently (step S14: No), the control unit 50d uses the above formula (9) to determine the flow rate Q of O2 supplied to the fuel tower 20. FR_O2 (Step S15C) The flow rate Q supplied to the fuel tower 20 is FR_O2 The control unit 50d is to use the O2 flow rate Q determined by the above formula (9) FR_O2 Substituting into the above formula (13) to determine the flow rate Q of H2 supplied to the fuel tower 20 FR_H2 (Step S16C) The determined flow rate Q is supplied to the fuel tower 20. FR_H2 The control unit 50d uses the above formula (14) to determine the flow rate Q of CH4 supplied to the fuel tower 20. FR_HC (Step S17C) The determined flow rate Q is supplied to the fuel tower 20. FR_HC of CH4.

[0107] When the control unit 50d performs any of steps S17A to S17C, it determines whether to terminate the flow control process (step S18). If it determines that the flow control process is not to be terminated (step S18: No), the process from step S12 onward is repeated. If it determines that the flow control process is to be terminated (step S18: Yes), the flow control process is terminated. It should be noted that the determination of whether to terminate the flow control process can also be made while other processes are being performed.

[0108] As described above, when the water electrolysis device 30d is performing water electrolysis and generating H2 and O2, the control unit 50d of this embodiment supplies the generated O2 along with CH4 to the fuel tower 20 and stores the generated H2 in the hydrogen tank 35. On the other hand, when the water electrolysis device 30d is not performing water electrolysis, the control unit 50d supplies the H2 stored in the hydrogen tank 35 along with CH4 to the fuel tower 20. That is, in this embodiment, when the power supply from the power supply device PW to the water electrolysis device 30d fluctuates, the supply of H2 and O2 from the water electrolysis device 30d is controlled based on the power supply. When the water electrolysis device 30d generates H2 and O2 due to power supply, the generated H2 is stored in the hydrogen tank 35. Meanwhile, the generated O2 is supplied to the fuel tower 20, oxidizing the metal particles mg and generating an exothermic reaction. As a result, the heat lost due to the reduction reaction of CH4 within the fuel tower 20 is replenished by this exothermic reaction. When the water electrolysis device 30d is not performing water electrolysis, H2 stored in the hydrogen tank 35 is supplied to the fuel tower 20. Heat lost due to the reduction reaction of CH4 is thereby compensated through a weakly exothermic reaction. Specifically, according to this embodiment, oxygen, a byproduct of water electrolysis, is effectively utilized based on the amount of power supplied to the water electrolysis device 30d. Furthermore, when no power is supplied, the H2 stored in the hydrogen tank 35 is used to heat the interior of the fuel tower 20. As a result, the overall energy efficiency of the combustion system 100d is improved.

[0109] <Modification of the Fifth Embodiment>

[0110] In the fifth embodiment, power is supplied from the power supply device PW to the water electrolysis device 30d, and O2 generated by the water electrolysis device 30d is supplied to the fuel tower 20. At this time, H2 is used as a fuel for reducing the metal particles mg reoxidized by O2 within the fuel tower 20 as shown in the above formula (10). However, the fuel used for reoxidation may be CH4, or both H2 and CH4.

[0111] In the fifth embodiment, the generated O2 is supplied to the fuel tower 20 during the same period as the period during which the water electrolysis device 30d generates O2. However, there may be periods during which the generated O2 is not supplied to the fuel tower 20. For example, when the amount of H2 stored in the hydrogen tank 35 is below a predetermined value, the controller 50d may release the O2 generated by water electrolysis into the atmosphere and store the generated H2 in the hydrogen tank 35 or supply it to the fuel tower 20. In this case, the combustion system 100d may include a heater 25 for heating the fuel tower 20. While the water electrolysis device 30d is performing water electrolysis, the controller 50d preferably supplies at least a portion of the generated H2 to the hydrogen tank 35. Furthermore, when the storage amount of the hydrogen tank 35 exceeds a predetermined upper limit, the controller 50d may supply only H2, rather than CH4, to the fuel tower 20 to promote H2 consumption.

[0112] <Sixth embodiment>

[0113] Figure 10 This is a schematic block diagram of a chemical looping combustion system (combustion system) 100e according to the sixth embodiment. Compared to the combustion system 100d according to the fifth embodiment, the combustion system 100e according to the sixth embodiment differs in that the O2 generated by the water electrolysis device 30 is supplied to the air column flow seal valve 60 instead of being supplied to the fuel column 20. In the sixth embodiment, only the components that differ from the fifth embodiment are described, and descriptions of the same components are omitted.

[0114] When the water electrolysis device 30e generates H2 and O2 by water electrolysis, the control unit 50e of the sixth embodiment stores the generated H2 in the hydrogen tank 35 and supplies the generated O2 to the air tower side flow sealing valve unit 60. If the flow rate of O2 supplied to the air tower side flow sealing valve unit 60 is defined as Q ULS_O2 , then the flow Q ULS_O2 The constant k5 and the flow rate Q of O2 flowing into the fuel tower 20 can be used FR_O2 It is represented by the following formula (15): It should be noted that the constant k5 is 1 or greater.

[0115]

[0116] In the above formula (15), when all the O2 supplied to the air column side flow seal valve portion 60 flows into the fuel column 20, k5 is 1. On the other hand, when all the O2 supplied to the air column side flow seal valve portion 60 flows into the oxidation column 10, k5 is infinite. Therefore, the control unit 50e uses the O2 flow rate Q determined by formula (15) FR_O2 As in the fifth embodiment Figure 9 Various flow rates supplied to the fuel tower 20 are controlled as shown in the flow control flow chart.

[0117] <Modification of the embodiment>

[0118] The present invention is not limited to the above-described embodiments and can be implemented in various ways without departing from the scope of the present invention. For example, the following modifications are possible. In addition, in the above-described embodiments, a portion of the components implemented by hardware can be replaced by software, and conversely, a portion of the components implemented by software can be replaced by hardware.

[0119] While the first to sixth embodiments described above illustrate a chemical looping combustion system, the chemical looping combustion system can be modified to include an oxidation tower 10 for oxidizing metal particles mg and a fuel tower 20 for reducing metal particles mg using a carbon-containing compound and H₂ supplied as fuel. For example, the combustion system 100 may not include the air tower flow seal valve 60 or the fuel tower flow seal valve 70. In the combustion system 100a of the second embodiment, H₂ and O₂ generated by the water electrolysis device 30 are supplied to the fuel tower 20. However, the H₂ and O₂ may be supplied from other devices or gas storage tanks rather than through water electrolysis. The power supply device PW included in the combustion system 100d of the fifth embodiment is a solar cell, but a known power supply using regenerative energy or other power supply may be used as a power source for variable power supply. The power supply device PW may also be an external power source not included in the combustion system 100d.

[0120] The gas containing O2 supplied to the oxidation tower 10 may be other than air. The oxidation tower 10 may also be called an air tower to which air containing oxygen is supplied. The combustion system 100 may include a heater 25 ( Figure 3 ), in the fuel tower 20, in addition to the heating by the reduction reaction of the metal particles mg based on H 2 and the oxidation reaction of the metal particles mg based on O 2, heating by the heater 25 can also be used.

[0121] As the metal particles mg circulating in the combustion system 100, known materials other than Fe3O4 can be used. For example, as the reaction formula for reducing the oxidized metal particles mg with H2, Ni and FeTiO3 represented by the following reaction formulas (16) and (17) can be used as the metal particles mg.

[0122]

[0123]

[0124] The carbon-containing compound used as fuel supplied to the fuel tower 20 may be C₂H₆, C₃H₆, or other compounds other than hydrocarbons, such as CH₄. For example, when C₂H₆ is used as the carbon-containing compound, the reaction equation for the reduction of Fe₂O₃, which is the oxidized metal particle mg, is as shown in the following equation (18).

[0125]

[0126] The present invention has been described above based on the embodiments and variations. However, the embodiments described above are intended to facilitate understanding of the present invention and do not limit the present invention. The present invention may be modified and improved without departing from its main purpose and the claims, and equivalents thereof are included in the present invention. Furthermore, if a technical feature is not described as an essential feature in this specification, it may be deleted as appropriate.

[0127] The present invention can also be implemented in the following forms.

[0128] [Application Example 1]

[0129] A chemical looping combustion system comprising:

[0130] an oxidation tower that oxidizes the metal particles; and

[0131] A fuel tower is supplied with hydrogen gas and a carbon-containing compound as fuel and is supplied with oxidized metal particles from the oxidation tower, and reduces the metal particles using the fuel.

[0132] [Application Example 2]

[0133] The chemical looping combustion system according to Application Example 1 further comprises:

[0134] a temperature acquiring unit configured to acquire the temperature within the fuel tower; and

[0135] A control unit determines flow rates of hydrogen gas and carbon-containing compounds supplied to the fuel tower using a difference between the temperature acquired by the temperature acquisition unit and a predetermined temperature.

[0136] [Application Example 3]

[0137] According to the chemical looping combustion system described in Application Example 1 or Application Example 2, wherein:

[0138] It also includes a water electrolysis unit that electrolyzes water to generate hydrogen and oxygen.

[0139] The water electrolysis unit supplies the generated hydrogen and oxygen to the fuel tower.

[0140] [Application Example 4]

[0141] The chemical looping combustion system according to any one of Application Examples 1 to 3, wherein:

[0142] A flow sealing valve is further provided, the flow sealing valve being arranged on the downstream side of the oxidation tower and the upstream side of the fuel tower to prevent gas from flowing from the oxidation tower into the fuel tower.

[0143] The water electrolysis unit supplies the generated hydrogen to the fuel tower, and supplies the generated oxygen to the flow sealing valve instead of supplying it to the fuel tower.

[0144] [Application Example 5]

[0145] The chemical looping combustion system according to any one of Application Examples 1 to 4, wherein:

[0146] It also includes a hydrogen tank for storing hydrogen gas generated by the water electrolysis unit.

[0147] Regarding the above-mentioned control unit, when hydrogen and oxygen are generated by the above-mentioned water electrolysis unit, the generated oxygen is supplied to the above-mentioned fuel tower, and at least a portion of the generated hydrogen is stored in the above-mentioned hydrogen tank. When hydrogen and oxygen are not generated by the above-mentioned water electrolysis unit, the hydrogen stored in the above-mentioned hydrogen tank is supplied to the above-mentioned fuel tower.

[0148] Explanation of symbols

[0149] 10…Oxidation tower

[0150] 10S…Oxidation tower seal

[0151] 15…Cyclone separator

[0152] 20…Fuel tower

[0153] 20S...Fuel tower seal

[0154] 26…Temperature sensor

[0155] 25…Heater

[0156] 30, 30d, 30e…water electrolysis device (water electrolysis unit)

[0157] 35…Hydrogen tank

[0158] 40…Dehydrator

[0159] 50, 50d, 50e…control unit

[0160] 60...Flow sealing valve part on the air tower side (flow sealing valve)

[0161] 60S...Seal for the flow sealing valve on the air tower side

[0162] 70…Fuel tower side flow sealing valve

[0163] 70S...Seals for flow sealing valves in fuel towers

[0164] 100, 100a, 100b, 100c, 100d, 100e…combustion system

[0165] 100x...comparative example combustion system

[0166] PW…Variable power supply device

[0167] Q FR_H2 …the flow rate of hydrogen

[0168] Q FR_O2 …oxygen flow rate

[0169] Q FR_HC …the flow of methane

[0170] T FR ...the temperature inside the fuel tower

[0171] T FR_tar ...target temperature

[0172] mg…metal particles

Claims

1. A chemical looping combustion system comprising: an oxidation tower that oxidizes the metal particles; and A fuel tower is supplied with hydrogen gas and a carbon-containing compound as fuel and is supplied with oxidized metal particles from the oxidation tower, and reduces the metal particles using the fuel.

2. The chemical looping combustion system according to claim 1, wherein: Also features: a temperature acquiring unit configured to acquire a temperature within the fuel tower; and A control unit determines flow rates of hydrogen gas and carbon-containing compounds supplied to the fuel tower using a difference between the temperature acquired by the temperature acquisition unit and a predetermined temperature.

3. The chemical looping combustion system according to claim 1 or claim 2, wherein: It also includes a water electrolysis unit that electrolyzes water to generate hydrogen and oxygen. The water electrolysis unit supplies the generated hydrogen and oxygen to the fuel tower.

4. The chemical looping combustion system according to claim 3, wherein: A flow sealing valve is further provided, the flow sealing valve being arranged on the downstream side of the oxidation tower and the upstream side of the fuel tower to prevent gas from flowing from the oxidation tower into the fuel tower. The water electrolysis unit supplies the generated hydrogen to the fuel tower, and supplies the generated oxygen to the flow sealing valve instead of supplying it to the fuel tower.

5. The chemical looping combustion system according to claim 4, wherein: A hydrogen tank is further provided, wherein the hydrogen tank stores hydrogen gas generated by the water electrolysis unit. Regarding the control unit, when hydrogen and oxygen are generated by the water electrolysis unit, the generated oxygen is supplied to the fuel tower, and at least a portion of the generated hydrogen is stored in the hydrogen tank. When hydrogen and oxygen are not generated by the water electrolysis unit, the hydrogen stored in the hydrogen tank is supplied to the fuel tower.

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