Chemical loop combustion system

Abstract

To provide a technique capable of adjusting heat quantity recovered from an air tower and an amount of carbon dioxide recovered from a fuel tower.SOLUTION: A chemical loop combustion system includes: an air tower for oxidizing metallic particles by causing the metallic particles and gas to react with each other; a fuel tower for reducing the metallic particles by causing the oxidized metallic particles and fuel to react with each other; circulation piping for circulating the metallic particles between the air tower and the fuel tower; and a control section for controlling the chemical loop combustion system. The control section performs adjustment control for adjusting an amount of the metallic particles to be oxidized and an amount of the metallic particles to be reduced.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] A chemical looping combustion system is a system in which metal particles are circulated and fluidized between an air reactor that oxidizes the metal particles and a fuel reactor that reduces the metal particles. As another device involving the flow of powder or particles, Patent Document 1 discloses a powder conveying device that conveys powder such as a developer. Further, Patent Document 2 discloses a multi-chamber fluidized bed reactor that causes particles to flow between divided chambers.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Patent Document 2

Summary of Invention

Problem to be Solved by the Invention

[0004] In a chemical looping combustion system, mainly thermal energy can be recovered from the air reactor, and mainly carbon dioxide can be recovered from the fuel reactor. It is preferable that the amount of recovered heat and the amount of carbon dioxide can be adjusted as needed, and there has been a demand for a technology that enables such adjustment. It should be noted that the devices disclosed in Patent Documents 1 and 2 do not consider such adjustment at all.

[0005] The present invention has been made to solve at least part of the above-mentioned problems, and an object of the present invention is to provide a chemical looping combustion system capable of adjusting the amount of heat recovered from the air reactor and the amount of carbon dioxide recovered from the fuel reactor.

Means for Solving the Problem

[0006] The present invention has been made to solve at least some of the above-mentioned problems and can be realized in the following forms.

[0007] (1) According to one embodiment of the present invention, a chemical loop combustion system is provided. This chemical loop combustion system comprises an air tower that reacts metal particles with a gas to oxidize the metal particles, a fuel tower that reacts the oxidized metal particles with a fuel to reduce the metal particles, a circulation pipe that circulates the metal particles between the air tower and the fuel tower, and a control unit that controls the chemical loop combustion system, wherein the control unit performs adjustment control to adjust the amount of metal particles that are oxidized and the amount of metal particles that are reduced.

[0008] This configuration allows for the adjustment of the amount of metal particles oxidized and the amount of metal particles reduced. Consequently, the amount of heat recovered from the air tower and the amount of carbon dioxide recovered from the fuel tower can be adjusted.

[0009] (2) In the chemical loop combustion system of the above form, the system further comprises a gas quantity adjustment unit for adjusting the amount of gas supplied to the air tower, a fuel quantity adjustment unit for adjusting the amount of fuel supplied to the fuel tower, a storage unit capable of storing the metal particles, and a branch pipe branching off from the circulation pipe and connected to the storage unit, wherein the branch pipe is provided with a flow path on / off valve for opening and closing the flow path within the branch pipe, and the control unit may, as adjustment control, increase or decrease the amount of metal particles circulating within the chemical loop combustion system by opening the flow path on / off valve and storing the metal particles in the storage unit from the circulation pipe, or by opening the flow path on / off valve and releasing the metal particles from the storage unit to the circulation pipe, and may also increase or decrease the amount of gas and the amount of fuel in accordance with the increase or decrease in the amount of circulation. This configuration allows for increasing or decreasing the circulation rate of metal particles through storage and release from the storage unit, while simultaneously increasing or decreasing the amount of gas supplied to the air tower and the amount of fuel supplied to the fuel tower in accordance with the increase or decrease in the circulation rate. Therefore, even after increasing or decreasing the circulation rate, appropriate circulation of metal particles can be maintained, and the appropriate amount of gas for the oxidation reaction and the appropriate amount of fuel for the reduction reaction can be supplied to the air tower and fuel tower. Consequently, since the amount of metal particles oxidized and reduced can be increased or decreased in proportion to the increase or decrease in the circulation rate, the amount of heat and carbon dioxide recovered from the chemical loop combustion system can be precisely controlled.

[0010] (3) In the chemical loop combustion system of the above form, further comprising a plurality of air towers, a plurality of fuel towers, a plurality of gas quantity adjustment units for adjusting the amount of gas supplied to each of the air towers, and a plurality of fuel quantity adjustment units for adjusting the amount of fuel supplied to each of the fuel towers, wherein the circulation piping includes a first pipe through which the metal particles can flow to each of the fuel towers, and a second pipe through which the metal particles can flow to each of the air towers, and the first pipe opens each of the first individual flow paths for flowing the metal particles to each of the fuel towers. A plurality of first on-off valves are provided to be closed, and the second piping is provided with a plurality of second on-off valves that open and close each of the second individual flow paths that allow the metal particles to flow to each of the air towers, and the control unit may, as adjustment control, adjust the number of first on-off valves to be opened and the number of second on-off valves to be opened, and may also supply the fuel to the fuel tower in which the metal particles have become able to flow by opening the first on-off valves, and supply the gas to the air tower in which the metal particles have become able to flow by opening the second on-off valves. This configuration allows for the adjustment of the number of air towers and fuel towers through which metal particles can circulate by adjusting the number of first and second valves that are opened, thereby increasing or decreasing the circulation rate of metal particles. Furthermore, opening the first valves allows for the supply of fuel to the fuel towers through which metal particles can circulate, and opening the second valves allows for the supply of gas to the air towers through which metal particles can circulate. Therefore, even after increasing or decreasing the circulation rate, appropriate circulation of metal particles can be maintained, while supplying the appropriate amount of gas for the oxidation reaction and the appropriate amount of fuel for the reduction reaction to the air towers and fuel towers. Consequently, the amount of metal particles oxidized and reduced can be increased or decreased in proportion to the increase or decrease in the circulation rate, allowing for precise adjustment of the amount of heat recovered from the air towers and the amount of carbon dioxide recovered from the fuel towers.

[0011] (4) In the chemical loop combustion system of the above form, the control unit may further include a gas quantity adjustment unit for adjusting the amount of gas supplied to the air tower, a fuel quantity adjustment unit for adjusting the amount of fuel supplied to the fuel tower, a first inert gas adjustment unit for adjusting the amount of inert gas supplied to the air tower, and a second inert gas adjustment unit for adjusting the amount of inert gas supplied to the fuel tower, wherein the control unit may, as the adjustment control, adjust the ratio of the gas and the ratio of the inert gas to the total amount without changing the total amount of the gas and the amount of inert gas supplied to the air tower, and adjust the ratio of the fuel and the ratio of the inert gas to the total amount without changing the total amount of the fuel and the amount of inert gas supplied to the fuel tower. This configuration allows for increasing or decreasing the amount of oxidized and reduced metal particles without changing the total amount of gas (gas and inert gas) supplied to the air tower and the total amount of gas (fuel and inert gas) supplied to the fuel tower. Therefore, it is possible to precisely adjust the amount of heat recovered from the air tower and the amount of carbon dioxide recovered from the fuel tower while maintaining proper circulation of metal particles.

[0012] Furthermore, the present invention can be realized in various forms, for example, as a chemical loop combustion system, a chemical loop combustion plant, a chemical loop combustion apparatus, apparatus and systems comprising these, a method for producing carbon dioxide, a method for synthesizing carbon dioxide, a computer program for executing these apparatus and methods, a server apparatus for distributing this computer program, and a non-temporary storage medium storing the computer program. [Brief explanation of the drawing]

[0013] [Figure 1] This is an explanatory diagram illustrating the configuration of the chemical loop combustion system of the first embodiment. [Figure 2] This is an explanatory diagram illustrating the configuration of a chemical loop combustion system according to the second embodiment. [Figure 3] This is an explanatory diagram illustrating the configuration of a chemical loop combustion system according to the third embodiment. [Modes for carrying out the invention]

[0014] <First Embodiment> Figure 1 is an explanatory diagram illustrating the configuration of a chemical loop combustion system 1 as a first embodiment of the present invention. The chemical loop combustion system 1 is a system that recovers thermal energy and carbon dioxide, etc., by oxidation and reduction reactions using metal particles MP circulating within the system. Examples of metal particles MP, which are oxygen carriers, include oxides of nickel, iron, copper, manganese, etc. The chemical loop combustion system 1 comprises a gas shut-off valve 10V, an air tower 10, a cyclone 20, a first loop seal section 30, a fuel shut-off valve 40V, a fuel tower 40, a second loop seal section 50, a circulation pipe 60, and a control section 70.

[0015] The gas on / off valve 10V is an electric valve or solenoid valve capable of changing its opening degree according to a control signal from the control unit 70, which will be described later. The gas on / off valve 10V is installed in the piping (not shown) that supplies gas to the air tower 10. The gas on / off valve 10V corresponds to the gas amount adjustment unit and adjusts the amount of gas supplied to the air tower 10. The gas supplied to the air tower 10 is an oxygen-containing gas, and in this embodiment, it is air. The air tower 10 is a tower that reacts metal particles MP with gas to oxidize the metal particles MP. Oxidation heat is generated inside the air tower 10 due to the oxidation of the metal particles MP.

[0016] Cyclone 20 is connected to the upper part of the air tower 10 in the direction of gravity, and separates the metal particles MP sent from the air tower 10 from the exhaust gas based on the difference in specific gravity. This exhaust gas is formed by the oxidation reaction with the metal particles MP, which removes oxygen from the gas, and since the gas in this embodiment is air, it contains a high concentration of nitrogen. This exhaust gas is sent out of cyclone 20 from the upper part of cyclone 20 in the direction of gravity. The thermal energy contained in this exhaust gas is recovered by a heat exchanger (not shown).

[0017] The first loop seal section 30 is connected to the lower part of the cyclone 20 in the direction of gravity and receives metal particles MP separated from the exhaust gas in the cyclone 20. Within the first loop seal section 30, water vapor is appropriately supplied as a sealing gas to prevent contact between the gas supplied to the air tower 10 and the fuel supplied to the fuel tower 40, which will be described later. This sealing gas also assists in the flow of the metal particles MP within the first loop seal section 30.

[0018] Like the gas on-off valve 10V, the fuel on-off valve 40V is an electrically operated valve or a solenoid valve whose opening degree can be changed in accordance with a control signal from a control unit 70 to be described later. The fuel on-off valve 40V is provided in a pipe (not shown) that supplies fuel to the fuel tower 40. The fuel on-off valve 40V corresponds to a fuel amount adjustment unit and adjusts the amount of fuel supplied to the fuel tower 40. The fuel referred to herein is a hydrocarbon such as methane. The fuel tower 40 is a tower that reduces the metal particles MP by reacting oxidized metal particles MP with the fuel. In the fuel tower 40, reduction of the metal particles MP generates exhaust gas composed of carbon dioxide and water. This exhaust gas is sent out of the fuel tower 40 from a portion on the upper side of the fuel tower 40 in the direction of gravity. The thermal energy contained in this exhaust gas is recovered by a heat exchanger (not shown). Furthermore, carbon dioxide is recovered by treating this exhaust gas with a dehydrator. The fuel tower 40 includes an electric heater 40H that heats the inside of the fuel tower 40 to promote the reduction of the metal particles MP within the fuel tower 40.

[0019] The second loop seal portion 50 is connected to a lower portion of the fuel tower 40 in the direction of gravity, and receives the metal particles MP separated from the exhaust gas in the fuel tower 40. In the same manner as in the first loop seal portion 30, seal gas is appropriately fed into the second loop seal portion 50, whereby contact between gas and fuel is prevented and flow of the metal particles MP in the second loop seal portion 50 is assisted.

[0020] The circulation pipe 60 is a pipe that circulates the metal particles MP between the air tower 10 and the fuel tower 40. The circulation pipe 60 includes a first pipe 61 and a second pipe 62. The first pipe 61 is a pipe connecting the first loop seal part 30 and the fuel tower 40, and defines a flow path through which the metal particles MP flow from the first loop seal part 30 to the fuel tower 40. The metal particles MP used for the reduction reaction in the fuel tower 40 are sent from the first loop seal part 30 to the fuel tower 40 via the first pipe 61. On the other hand, the second pipe 62 is a pipe connecting the second loop seal part 50 and the air tower 10, and defines a flow path through which the metal particles MP flow from the second loop seal part 50 to the air tower 10. The metal particles MP used for the oxidation reaction in the air tower 10 are sent from the second loop seal part 50 to the air tower 10 via the second pipe 62.

[0021] The control unit 70 is configured of an ECU (Electronic Control Unit) and controls the chemical looping combustion system 1. In the present embodiment, the control unit 70 controls the opening degrees of at least the gas on-off valve 10V and the fuel on-off valve 40V.

[0022] The chemical loop combustion system 1 further comprises a gas shut-off valve 80V, a reservoir tank 80, a branch pipe 82, and a flow path shut-off valve 82V. The gas shut-off valve 80V is installed in the piping (not shown) that supplies gas to the reservoir tank 80 and adjusts the amount of gas supplied to the reservoir tank 80. The gas supplied to the reservoir tank 80 is air, similar to the gas supplied to the air tower 10. The reservoir tank 80 corresponds to a storage section and is a tank capable of storing metal particles MP. The branch pipe 82 is a pipe that branches off from the circulation pipe 60 and connects to the reservoir tank 80, defining a flow path through which metal particles MP can flow between the circulation pipe 60 and the reservoir tank 80. In this embodiment, the branch pipe 82 branches off from the second pipe 62 of the circulation pipe 60 and connects to the reservoir tank 80, defining a flow path through which metal particles MP can flow between the second pipe 62 and the reservoir tank 80. The flow path shut-off valve 82V, provided in the branch pipe 82, opens and closes the flow path within the branch pipe 82. In this embodiment, the control unit 70 controls the opening degrees of the gas shut-off valve 10V and the fuel shut-off valve 40V, as well as the opening degrees of the gas shut-off valve 80V and the flow path shut-off valve 82V.

[0023] In the chemical loop combustion system 1, the control unit 70 adjusts the amount of metal particles MP oxidized in the air tower 10 and the amount of metal particles MP reduced in the fuel tower 40 in order to adjust the amount of thermal energy (heat) recovered from the air tower 10 and the amount of carbon dioxide recovered from the fuel tower 40 as needed. In this embodiment, the circulation rate of metal particles MP circulating within the chemical loop combustion system 1 is increased or decreased in order to adjust the amount of metal particles MP oxidized in the air tower 10 and the amount of metal particles MP reduced in the fuel tower 40. The circulation rate here refers to the amount of metal particles MP circulating in the air tower 10, cyclone 20, first loop seal section 30, first piping 61, fuel tower 40, second loop seal section 50, and second piping 62.

[0024] In detail, the control unit 70 increases or decreases the amount of metal particles MP circulating within the chemical loop combustion system 1 by either opening the flow path valve 82V to store metal particles MP from the second pipe 62 into the reservoir tank 80 (storage control), or by opening the flow path valve 82V to release metal particles MP from the reservoir tank 80 into the second pipe 62 (release control). In this embodiment, since the reservoir tank 80 is located lower in the direction of gravity than the second pipe 62, the branch pipe 82 also extends downward in the direction of gravity. Therefore, in storage control, the control unit 70 opens the flow path valve 82V (opening > 0) to allow flow through the branch pipe 82, and stores metal particles MP in the reservoir tank 80 by causing the metal particles MP flowing through the flow path in the second pipe 62 to fall from the branch pipe 82 into the reservoir tank 80. Note that the gas valve 80V is assumed to be closed during storage control. On the other hand, in release control, the control unit 70 opens both the gas shut-off valve 80V and the flow path shut-off valve 82V (opening degree > 0) to allow gas to flow through the branch pipe 82 and supplies gas to the reservoir tank 80, thereby releasing metal particles MP from the reservoir tank 80 into the second pipe 62. In other words, in this embodiment, storage control and release control have in common that the flow path shut-off valve 82V is opened, but they differ in whether or not the gas shut-off valve 80V is opened. Through such storage control and release control, the amount of metal particles MP circulating within the chemical loop combustion system 1 is increased or decreased.

[0025] Furthermore, the control unit 70 increases or decreases the amount of gas supplied to the air tower 10 and the amount of fuel supplied to the fuel tower 40 in accordance with the increase or decrease in the circulation rate of metal particles MP. Here, the amount of gas (or fuel) supplied to the air tower 10 (or fuel tower 40) refers to the amount of gas (or fuel) supplied to the air tower 10 (or fuel tower 40) per unit time. For example, if the circulation rate of metal particles MP decreases due to storage control, the control unit 70 decreases the opening of both the gas shut-off valve 10V and the fuel shut-off valve 40V, thereby decreasing the amount of gas supplied to the air tower 10 and the amount of fuel supplied to the fuel tower 40. On the other hand, if the circulation rate of metal particles MP increases due to release control, the control unit 70 increases the opening of both the gas shut-off valve 10V and the fuel shut-off valve 40V, thereby increasing the amount of gas supplied to the air tower 10 and the amount of fuel supplied to the fuel tower 40. The circulation rate of metal particles MP is estimated based on the pressure loss between two locations within the chemical loop combustion system 1. In this embodiment, the amount of metal particles MP circulated is estimated based on the pressure loss between position P1 in the air tower 10 (the position before the gas supplied to the air tower 10 comes into contact with the metal particles MP accumulated on the lower side in the direction of gravity within the air tower 10) and position P2 (a position in the air tower 10 that is above the position where the metal particles MP are accumulated in the direction of gravity).

[0026] For example, if the amount of gas supplied to the air tower 10 and the amount of fuel supplied to the fuel tower 40 are reduced without increasing or decreasing the circulation rate of metal particles MP in order to reduce the amount of thermal energy (heat) recovered from the air tower 10 and the amount of carbon dioxide recovered from the fuel tower 40, this will lead to a decrease in the circulation speed of each of the metal particles MP circulating within the chemical loop combustion system 1, making it easier for metal particles MP to accumulate. Similarly, if the amount of gas supplied to the air tower 10 and the amount of fuel supplied to the fuel tower 40 are not changed, but only the circulation rate of metal particles MP is increased in order to increase the amount of thermal energy (heat) recovered from the air tower 10 and the amount of carbon dioxide recovered from the fuel tower 40, metal particles MP will also be more likely to accumulate. Such accumulation can hinder the circulation of metal particles MP within the chemical loop combustion system 1, and consequently, there is a risk that the oxidation reaction in the air tower 10 and the reduction reaction in the fuel tower 40 will not occur. In other words, in the chemical loop combustion system 1, it is preferable to suppress the accumulation of metal particles MP by increasing or decreasing the circulation rate of metal particles MP, the amount of gas supplied to the air tower 10, and the amount of fuel supplied to the fuel tower 40 in conjunction.

[0027] In this regard, in the chemical loop combustion system 1 of the first embodiment, the circulation rate of metal particles MP is increased or decreased by storing metal particles MP in the reservoir tank 80 and releasing metal particles MP from the reservoir tank 80, and the amount of gas supplied to the air tower 10 and the amount of fuel supplied to the fuel tower 40 are increased or decreased in accordance with the increase or decrease in the circulation rate. Therefore, even after the increase or decrease in the circulation rate, appropriate circulation of metal particles MP can be maintained, and an appropriate amount of gas for the oxidation reaction and an appropriate amount of fuel for the reduction reaction can be supplied to the air tower 10 and the fuel tower 40. Thus, since the amount of metal particles oxidized and the amount of metal particles reduced can be increased or decreased in proportion to the increase or decrease in the circulation rate, the amount of heat recovered from the air tower 10 and the amount of carbon dioxide recovered from the fuel tower 40 can be adjusted with precision. The appropriate amount mentioned above refers to the amount of gas and fuel sufficient to carry out the oxidation reaction and the reduction reaction in relation to the amount of metal particles MP sequentially supplied to the air tower 10 and the fuel tower 40.

[0028] <Second Embodiment> Figure 2 is an explanatory diagram illustrating the configuration of a chemical loop combustion system 1a as a second embodiment of the present invention. The chemical loop combustion system 1a of the second embodiment differs from the chemical loop combustion system 1 of the first embodiment mainly in that it does not have a gas shut-off valve 80V, a reservoir tank 80, branch piping 82 and a flow path shut-off valve 82V, and it has a plurality of air towers 11 to 13 and a plurality of fuel towers 41 to 43.

[0029] Each of the air towers 11 to 13 is a tower that reacts metal particles MP with gas to oxidize the metal particles MP, similar to the air tower 10 of the first embodiment. The upper part of each of the air towers 11 to 13 in the direction of gravity is connected to the cyclone 20. Each of the gas on-off valves 11V to 13V is an electric valve or solenoid valve whose opening degree can be changed according to a control signal from the control unit 70. Each of the gas on-off valves 11V to 13V is installed in the piping (not shown) that supplies gas to each of the air towers 11 to 13 and adjusts the amount of gas supplied to the air towers 11 to 13. Each of the fuel towers 41 to 43 is a tower that reacts the oxidized metal particles MP with fuel to reduce the metal particles MP, similar to the fuel tower 40 of the first embodiment. The lower part of each of the fuel towers 41 to 43 in the direction of gravity is connected to the second loop seal section 50. Although not shown in Figure 2, each of the fuel towers 41 to 43 has an electric heater, similar to the first embodiment. Each of the fuel on-off valves 41V to 43V is either an electric valve or a solenoid valve whose opening degree can be changed according to a control signal from the control unit 70. Each of the fuel on-off valves 41V to 43V is installed in the piping (not shown) that supplies gas to each of the fuel towers 41 to 43, and adjusts the amount of fuel supplied to the fuel towers 41 to 43.

[0030] The circulation piping 60a of the second embodiment includes a first pipe 61a and a second pipe 62a. The first pipe 61a of the second embodiment connects the first loop seal section 30 to each of the fuel towers 41 to 43 and is a pipe that allows metal particles MP to flow to each of the fuel towers 41 to 43. The first pipe 61a defines a plurality of first individual flow paths F1 to F3 that allow metal particles MP to flow from the first loop seal section 30 to each of the fuel towers 41 to 43. The first pipe 61a is provided with a plurality of first on-off valves V1 to V3 that open and close each of the first individual flow paths F1 to F3.

[0031] The second piping 62a of the second embodiment connects the second loop seal section 50 to each of the air towers 11 to 13, and is a piping that allows metal particles MP to flow to each of the air towers 11 to 13. The second piping 62a defines a plurality of second individual flow paths F4 to F6 that allow metal particles MP to flow from the second loop seal section 50 to each of the air towers 11 to 13. The second piping 62a is provided with a plurality of second on-off valves V4 to V6 that open and close each of the second individual flow paths F4 to F6.

[0032] In the second embodiment, in order to adjust the amount of metal particles MP to be oxidized and the amount of metal particles MP to be reduced, the control unit 70 adjusts the number of first on-off valves V1 to V3 to be opened and the number of second on-off valves V4 to V6 to be opened as adjustment control, and also supplies fuel to the fuel tower where metal particles MP can flow through by opening the first on-off valves V1 to V3 and supplies gas to the air tower where metal particles MP can flow through by opening the second on-off valves V4 to V6. For example, when the control unit 70 opens the first on-off valves V1 and V2 (two first on-off valves) among the first on-off valves V1 to V3, and opens the second on-off valves V4 and V5 (two second on-off valves) among the second on-off valves V4 to V6 (at which time the first on-off valve V3 and the second on-off valve V6 are closed), it opens the fuel on-off valves 41V and 42V to supply fuel to the fuel towers 41 and 42, and opens the gas on-off valves 11V and 12V to supply gas to the air towers 11 and 12.

[0033] According to the chemical loop combustion system 1a of the second embodiment described above, the circulation rate of metal particles MP can be increased or decreased by adjusting the number of air towers and fuel towers through which metal particles MP can flow by adjusting the number of first on-off valves V1 to V3 and the number of second on-off valves V4 to V6 that are opened. In addition, fuel is supplied to the fuel towers through which metal particles MP can flow by opening at least some of the first on-off valves V1 to V3, and gas is supplied to the air towers through which metal particles MP can flow by opening at least some of the second on-off valves V4 to V6. As a result, even after increasing or decreasing the circulation rate, appropriate circulation of metal particles MP can be maintained, and an appropriate amount of gas for the oxidation reaction and an appropriate amount of fuel for the reduction reaction can be supplied to the air towers 11 to 13 and fuel towers 41 to 43. Therefore, since the amount of metal particles MP oxidized and the amount of metal particles MP reduced can be increased or decreased in proportion to the increase or decrease in the circulation rate, the amount of heat and carbon dioxide recovered from the chemical loop combustion system 1a can be adjusted with high precision.

[0034] <Third Embodiment> Figure 3 is an explanatory diagram illustrating the configuration of a chemical loop combustion system 1b as a third embodiment of the present invention. The chemical loop combustion system 1b of the third embodiment differs from the chemical loop combustion system 1 of the first embodiment in that it does not have a gas shut-off valve 80V, a reservoir tank 80, branch piping 82 and a flow path shut-off valve 82V, but it does have an inert gas shut-off valve 10NV and an inert gas shut-off valve 40NV.

[0035] The inert gas shut-off valve 10NV is an electrically operated valve or solenoid valve capable of changing its opening degree according to a control signal from the control unit 70. The inert gas shut-off valve 10NV is installed in the piping (not shown) that supplies inert gas to the air tower 10. The inert gas shut-off valve 10NV corresponds to the first inert gas adjustment unit and adjusts the amount of inert gas supplied to the air tower 10. Examples of inert gases supplied to the air tower 10 include helium, neon, and argon.

[0036] The inert gas shut-off valve 40NV, like the inert gas shut-off valve 10NV, is an electrically operated valve or solenoid valve capable of changing its opening degree according to a control signal from the control unit 70. The inert gas shut-off valve 40NV is installed in the piping (not shown) that supplies inert gas to the fuel tower 40. The inert gas shut-off valve 40NV corresponds to the second inert gas adjustment unit and adjusts the amount of inert gas supplied to the fuel tower 40. Examples of inert gases supplied to the fuel tower 40 include helium, neon, and argon, similar to the inert gas supplied to the air tower 10.

[0037] In the third embodiment, in order to adjust the amount of metal particles MP oxidized in the air tower 10 and the amount of metal particles MP reduced in the fuel tower 40, the control unit 70 adjusts the ratio of gas and the ratio of inert gas in the total amount supplied to the air tower 10 without changing the total amount of gas and inert gas supplied to the air tower 10. The control unit 70 also adjusts the ratio of fuel and the ratio of inert gas in the total amount supplied to the fuel tower 40 without changing the total amount of fuel and inert gas supplied to the fuel tower 40. As mentioned above, the amount of gas (or fuel, inert gas) supplied to the air tower 10 (or fuel tower 40) refers to the amount of gas (or fuel, inert gas) supplied to the air tower 10 (or fuel tower 40) per unit time. The adjustment of the ratio of gas, the ratio of fuel gas, and the ratio of inert gas is performed by adjusting the opening of the gas shut-off valve 10V, the fuel shut-off valve 40V, the inert gas shut-off valve 10NV, and the inert gas shut-off valve 40NV.

[0038] For example, when the control unit 70 increases the amount of metal particles MP oxidized in the air tower 10 and the amount of metal particles MP reduced in the fuel tower 40, it increases the proportion of gas in the total amount supplied to the air tower 10 while decreasing the proportion of inert gas, without changing the total amount of gas and inert gas supplied to the air tower 10. At the same time, the control unit 70 increases the proportion of fuel in the total amount supplied to the fuel tower 40 while decreasing the proportion of inert gas, without changing the total amount of fuel and inert gas supplied to the fuel tower 40. Furthermore, when the control unit 70 decreases the amount of metal particles MP oxidized in the air tower 10 and the amount of metal particles MP reduced in the fuel tower 40, it decreases the proportion of gas in the total amount supplied to the air tower 10 while increasing the proportion of inert gas, without changing the total amount of gas and inert gas supplied to the air tower 10. At the same time, the control unit 70 decreases the proportion of fuel in the total amount supplied to the fuel tower 40 while increasing the proportion of inert gas, without changing the total amount of fuel and inert gas supplied to the fuel tower 40.

[0039] According to the chemical loop combustion system 1b of the third embodiment described above, the amount of metal particles MP oxidized and the amount of metal particles MP reduced can be increased or decreased without changing the total amount of gas (gas and inert gas) supplied to the air tower 10 per unit time and the total amount of gas (fuel and inert gas) supplied to the fuel tower 40 per unit time. Therefore, the amount of heat recovered from the air tower 10 and the amount of carbon dioxide recovered from the fuel tower 40 can be precisely adjusted while maintaining appropriate circulation of metal particles MP.

[0040] <Modified form of this embodiment> The present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from its spirit, for example, the following modifications are also possible.

[0041] In the first embodiment, the branch pipe 82 was connected to the reservoir tank 80 by branching off from the second pipe 62 of the circulation pipe 60, but is not limited to this. The branch pipe 82 may also be connected to the reservoir tank 80 by branching off from the first pipe 61 of the circulation pipe 60. Furthermore, in the first embodiment, the reservoir tank 80 was located below the second pipe 62 in the direction of gravity, but is not limited to this. The reservoir tank 80 may be located above the second pipe 62 (or the first pipe 61) in the direction of gravity. In this case, the control unit 70 may, in storage control, open the flow path valve 82V while creating negative pressure inside the reservoir tank 80 with a vacuum pump or the like, and suck the metal particles MP flowing through the flow path in the second pipe 62 (or the first pipe 61) from the branch pipe 82 to the reservoir tank 80, thereby storing the metal particles MP in the reservoir tank 80. Furthermore, in the discharge control, the control unit 70 may open the flow path valve 82V, causing the metal particles MP stored in the reservoir tank 80 to fall into the second pipe 62 (or the first pipe 61), thereby releasing the metal particles MP from the reservoir tank 80 into the second pipe 62.

[0042] In Figure 2 used to describe the second embodiment, each of the air towers 11-13 and each of the fuel towers 41-43 were shown as air towers and fuel towers of the same size, but this is not limited to them. The multiple air towers and multiple fuel towers that make up a chemical loop combustion system may be air towers and fuel towers of different sizes. Note that the larger the size, the greater the amount of metal particles MP that tend to accumulate in the air tower and fuel tower, and the smaller the size, the less the amount of metal particles MP that tend to accumulate in the air tower and fuel tower. Therefore, the more air towers and fuel towers of different sizes there are, the finer the adjustment becomes when adjusting the amount of metal particles MP that are oxidized and reduced, depending on which air towers and fuel towers are used to allow the flow of metal particles MP.

[0043] In the second embodiment, the first individual flow paths F1 to F3 were defined by one first pipe 61a, and the second individual flow paths F4 to F6 were defined by one second pipe 62a, but this is not limited to this. For example, the first individual flow paths F1 to F3 may be defined by each of three first pipes 61a, and the second individual flow paths F4 to F6 may be defined by each of three second pipes 62a. In this case, each of the first pipes 61a connects the first loop seal section 30 to the fuel towers 41 to 43, and each of the second pipes 62a connects the second loop seal section 50 to the air towers 11 to 13.

[0044] In the second embodiment, proper circulation of metal particles MP was maintained by supplying fuel to the fuel towers through which the metal particles MP could flow and by supplying gas to the air towers through which the metal particles MP could flow, but this is not limited to this. For example, in order to maintain proper circulation of metal particles MP, in addition to supplying fuel to the fuel towers and supplying gas to the air towers, the amount of sealing gas supplied to the first loop seal section 30 and the second loop seal section 50 may be increased. The amount of this sealing gas should be increased as the number of fuel towers and air towers through which the metal particles MP could flow increases.

[0045] The configurations of the chemical loop combustion systems 1, 1a, and 1b of the first to third embodiments described above, and the configurations of the modified examples described above, may be combined as appropriate. For example, the chemical loop combustion system 1 of the first embodiment may further include a plurality of air towers and a plurality of fuel towers, as described in the second embodiment, or inert gas on / off valves may be provided for the air towers and fuel towers, as described in the third embodiment. In addition, the chemical loop combustion system 1a of the second embodiment may further include inert gas on / off valves for each of the air towers and each of the fuel towers, as described in the third embodiment.

[0046] The embodiments of this specification have been described above based on the embodiments and modifications described above. The embodiments described above are for the purpose of facilitating understanding of this specification and do not limit it. This specification may be modified and improved without departing from its spirit and the scope of the claims, and equivalents thereof are included in this specification. Furthermore, any technical features that are not described as essential in this specification may be deleted as appropriate.

[0047] The present invention can also be realized in the following forms. [Application Example 1] A chemical loop combustion system, An air tower for reacting metal particles with gas to oxidize the metal particles, A fuel tower that reacts the oxidized metal particles with fuel to reduce the metal particles, A circulation pipe for circulating the metal particles between the air tower and the fuel tower, The system comprises a control unit for controlling the chemical loop combustion system, The control unit performs adjustment control to adjust the amount of metal particles that are oxidized and the amount of metal particles that are reduced in a chemical loop combustion system. [Application Example 2] The chemical loop combustion system described in Application Example 1, further, A gas quantity adjustment unit that adjusts the amount of gas supplied to the air tower, A fuel quantity adjustment unit that adjusts the amount of fuel supplied to the fuel tower, A storage section capable of storing the aforementioned metal particles, The system includes a branch pipe that branches off from the circulation pipe and connects to the storage section, The branch pipe is provided with a flow control valve that opens and closes the flow path within the branch pipe. The control unit, as the adjustment control, increases or decreases the amount of metal particles circulating within the chemical loop combustion system by opening the flow path valve and storing the metal particles in the storage section from the circulation piping, or by opening the flow path valve and releasing the metal particles from the storage section into the circulation piping, and increases or decreases the amount of gas and the amount of fuel in accordance with the increase or decrease in the amount of circulation, wherein the control unit increases or decreases the amount of gas and the amount of fuel, [Application Example 3] A chemical loop combustion system as described in Application Example 1 or Application Example 2, further comprising: Multiple air towers, Multiple fuel towers, A plurality of gas quantity adjustment units that adjust the amount of gas supplied to each of the air towers, A plurality of fuel quantity adjustment units that adjust the amount of fuel supplied to each of the fuel towers, Equipped with, The circulation piping includes a first pipe through which the metal particles can be circulated to each of the fuel towers, and a second pipe through which the metal particles can be circulated to each of the air towers. The first piping is provided with a plurality of first on-off valves that open and close each of the first individual flow paths that circulate the metal particles to each of the fuel towers. The second piping is provided with a plurality of second on-off valves that open and close each of the second individual flow paths that circulate the metal particles to each of the air towers. A chemical loop combustion system in which the control unit, as adjustment control, adjusts the number of first on-off valves to be opened and the number of second on-off valves to be opened, and supplies the fuel to the fuel tower in which the metal particles become available for passage when the first on-off valves are opened, and supplies the gas to the air tower in which the metal particles become available for passage when the second on-off valves are opened. [Application Example 4] A chemical loop combustion system described in any of Application Examples 1 to 3, further comprising: A gas quantity adjustment unit that adjusts the amount of gas supplied to the air tower, A fuel quantity adjustment unit that adjusts the amount of fuel supplied to the fuel tower, A first inert gas adjustment unit adjusts the amount of inert gas supplied to the air tower, The system includes a second inert gas adjustment unit for adjusting the amount of inert gas supplied to the fuel tower, A chemical loop combustion system in which the control unit adjusts, as the adjustment control, the ratio of the gas and the ratio of the inert gas to the total amount supplied to the air tower without changing the total amount of the gas and the amount of the inert gas supplied to the air tower, and the ratio of the fuel and the ratio of the inert gas to the total amount supplied to the fuel tower without changing the total amount of the fuel and the amount of the inert gas supplied to the fuel tower. [Explanation of Symbols]

[0048] 1,1a,1b…Chemical Loop Combustion System 10, 11-13... Air tower 10NV…Inert gas shut-off valve 10V, 11V~13V... Gas shut-off valve 20...Cyclone 30...First loop seal section 40,41~43…Fuel tower 40H…Electric heater 40NV...Inert gas shut-off valve 40V, 41V~43V... Fuel shut-off valve 50...Second loop seal section 60,60a… Circulation piping 61,61a...First piping 62,62a...Second piping 70... Control Unit 80... Reservoir Tank 80V...Gas shut-off valve 82... Branch piping 82V...Flow path opening / closing valve F1~F3...First individual channel F4~F6...Second individual channel V1~V3...First shut-off valve V4~V6...Second shut-off valve

Claims

1. A chemical loop combustion system, An air tower for reacting metal particles with gas to oxidize the metal particles, A fuel tower that reacts the oxidized metal particles with fuel to reduce the metal particles, A circulation pipe for circulating the metal particles between the air tower and the fuel tower, A control unit for controlling the chemical loop combustion system, A gas quantity adjustment unit that adjusts the amount of gas supplied to the air tower, A fuel quantity adjustment unit that adjusts the amount of fuel supplied to the fuel tower, A storage section capable of storing the aforementioned metal particles, The system includes a branch pipe that branches off from the circulation pipe and connects to the storage section, The branch pipe is provided with a flow control valve that opens and closes the flow path within the branch pipe. The control unit increases or decreases the amount of metal particles circulating within the chemical loop combustion system by adjusting the amount of metal particles to be oxidized and the amount of metal particles to be reduced, by opening the flow path valve and storing the metal particles in the storage section from the circulation pipe, or by opening the flow path valve and releasing the metal particles from the storage section into the circulation pipe, and increases or decreases the amount of gas and the amount of fuel in accordance with the increase or decrease in the amount of circulation.

2. A chemical loop combustion system, Multiple air towers for reacting metal particles with gas to oxidize the metal particles, Multiple fuel towers that react the oxidized metal particles with fuel to reduce the metal particles, A circulation pipe for circulating the metal particles between the air tower and the fuel tower, A control unit for controlling the chemical loop combustion system, A plurality of gas quantity adjustment units that adjust the amount of gas supplied to each of the air towers, The system includes a plurality of fuel quantity adjustment units that adjust the amount of fuel supplied to each of the fuel towers, The circulation piping includes a first pipe through which the metal particles can be circulated to each of the fuel towers, and a second pipe through which the metal particles can be circulated to each of the air towers. The first piping is provided with a plurality of first on-off valves that open and close each of the first individual flow paths that circulate the metal particles to each of the fuel towers. The second piping is provided with a plurality of second on-off valves that open and close each of the second individual flow paths that circulate the metal particles to each of the air towers. The control unit adjusts the number of first on-off valves to be opened and the number of second on-off valves to be opened as adjustment control to adjust the amount of metal particles to be oxidized and the amount of metal particles to be reduced, and also supplies the fuel to the fuel tower through which the metal particles have become circulating due to the opening of the first on-off valve, and supplies the gas to the air tower through which the metal particles have become circulating due to the opening of the second on-off valve, in a chemical loop combustion system.

3. A chemical loop combustion system, An air tower for reacting metal particles with gas to oxidize the metal particles, A fuel tower that reacts the oxidized metal particles with fuel to reduce the metal particles, A circulation pipe for circulating the metal particles between the air tower and the fuel tower, A control unit for controlling the chemical loop combustion system, A gas quantity adjustment unit that adjusts the amount of gas supplied to the air tower, A fuel quantity adjustment unit that adjusts the amount of fuel supplied to the fuel tower, A first inert gas adjustment unit that adjusts the amount of inert gas supplied to the air tower, The system includes a second inert gas adjustment unit for adjusting the amount of inert gas supplied to the fuel tower, The control unit, as an adjustment control for adjusting the amount of metal particles to be oxidized and the amount of metal particles to be reduced, adjusts the ratio of the gas and the ratio of the inert gas to the total amount supplied to the air tower without changing the total amount of the gas and the amount of the inert gas supplied to the fuel tower without changing the total amount of the fuel and the ratio of the inert gas to the total amount supplied to the fuel tower, in a chemical loop combustion system.

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