Thermal power generation system and control device

Abstract

This invention provides a thermal power generation system that can suppress the decrease in power generation when power generation is not being suppressed by using the energy generated by a boiler while power generation is being suppressed. [Solution] In this embodiment, the combustion boiler of the thermal power generation system heats the transported water by burning it with a fuel containing carbon atoms to generate steam. The steam turbine is driven using the steam flowing out of the combustion boiler. The generator is driven using the driving force of the steam turbine. The condenser cools the exhaust from the steam turbine and condenses it into water. The pump circulates the water. The carbon dioxide recovery device recovers carbon dioxide from the combustion exhaust gas discharged by the combustion boiler. The heat storage tank absorbs and stores the heat contained in the heat source fluid, which is all or part of the steam flowing out of the combustion boiler, or the steam or water circulating inside the combustion boiler. The heat released from the heat storage tank is used as a heat source for the carbon dioxide recovery device.

Description

Technical Field

[0001] Embodiments of the present invention relate to a thermal power generation system and a control device.

Background Art

[0002] Measures against global warming are a global issue, and the application of technologies for recovering and storing carbon dioxide, which is a greenhouse gas, is being promoted. In this technology, before exhaust gas discharged from facilities that emit a large amount of carbon dioxide, such as thermal power plants that burn fossil fuels containing carbon atoms such as coal and natural gas, is released into the atmosphere, only carbon dioxide is separated and recovered from the exhaust gas, and it is injected into a stable stratum deep underground and stored for a long time. In addition, the application of technologies for effectively using the recovered carbon dioxide is also being promoted. In this technology, for example, by injecting carbon dioxide into an old oil field, while pushing out the remaining crude oil in the oil field by pressure, the carbon dioxide is stored underground. In this case, it also leads to an increase in oil production. Furthermore, efforts are also underway to use carbon dioxide as a resource to produce valuable substances by using it as a raw material for chemicals and fuels.

[0003] As an example of a carbon dioxide recovery method, the use of a carbon dioxide recovery device is known (see Patent Document 1). This carbon dioxide recovery device has an absorption tower that absorbs carbon dioxide into an absorption liquid containing moisture, a regeneration tower that releases carbon dioxide from the absorption liquid supplied from the absorption tower, and a reboiler that heats the absorption liquid of the regeneration tower. The absorption liquid is, for example, an aqueous amine solution. In addition, other generally known carbon dioxide recovery methods exist.

[0004] A thermal power generation system 200 as a conventional technology is an example in which a carbon dioxide recovery device 34 is incorporated into a coal-fired power plant. FIG. 13 is a diagram showing a configuration example of this conventional thermal power generation system 200. As shown in FIG. 13, the thermal power generation system 200 includes a combustion boiler 1, a condensate pump 9, a steam turbine 10, a carbon dioxide recovery device 34, and a condenser 35.

[0005] Here, combustion boiler 1 is, for example, a coal boiler, and fuel 2 is coal. Fuel 2 (coal) and combustion air 3 are introduced into combustion boiler 1 (coal boiler), and the coal 2 is burned to generate combustion exhaust gas 4. The carbon dioxide capture device 34 mainly consists of an absorption tower 5, a regeneration tower 6, a reboiler built into the regeneration tower 6, an absorbent pump, and an absorbent liquid. Note that the reboiler, absorbent pump, and absorbent liquid are not shown in the diagram.

[0006] Combustion exhaust gas 4 is introduced into absorption tower 5. The absorption tower is supplied with an absorbent liquid that absorbs carbon dioxide. This supplied absorbent liquid comes into gas-liquid contact with the introduced combustion exhaust gas 4 and absorbs the carbon dioxide in the combustion exhaust gas 4. As a result, the absorbent liquid flows into regeneration tower 6, and at the same time, the carbon dioxide 7 in the absorbent liquid also moves to regeneration tower 6. Meanwhile, the remaining combustion exhaust gas, from which the carbon dioxide has been absorbed by the absorbent liquid, is released into the atmosphere. In regeneration tower 6, the absorbent liquid is heated by a reboiler, releasing carbon dioxide 8 from the absorbent liquid. The absorbent liquid, having released the carbon dioxide 8 and returned to its original state, flows into absorption tower 5. This absorbent liquid is circulated between absorption tower 5 and regeneration tower 6 by an absorbent liquid pump. Note that the absorption of carbon dioxide 8 in absorption tower 5, its release in regeneration tower 6, and its movement from absorption tower 5 to regeneration tower 6 are depicted schematically rather than in detail.

[0007] The combustion exhaust gas 4, from which carbon dioxide 8 has been recovered, is released into the atmosphere. Although not shown in the diagram, the carbon dioxide 8 released from the absorbent liquid is transported to a storage facility or a facility for manufacturing valuable materials. In the combustion boiler 1, water 23 brought in by the condensate pump 9 is heated by the heat of the combustion exhaust gas 4 to produce steam 24. The steam 24 flows through the steam turbine 10 at low temperature and low pressure, rotating the steam turbine 10, which is the impeller, and a generator 40 mechanically connected to the steam turbine 10 generates electricity.

[0008] The steam 24 discharged from the steam turbine 10 is cooled by cooling water, such as seawater, in the condenser 35, converted to water 23, and circulated. Extracted steam 11 extracted from the middle of the steam turbine 10 flows into the reboiler built into the regeneration tower 6, heats the absorbent liquid after absorption, and then flows into the condenser 35 to be converted to water 23. It is also possible to incorporate a carbon dioxide capture device 34 into a biomass thermal power plant or a waste combustion power plant. In this case, the coal boiler in the above example can be replaced with a biomass boiler or a waste combustion boiler, respectively. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Patent No. 6392099 [Overview of the project] [Problems that the invention aims to solve]

[0010] However, in coal-fired power plants, biomass-fired power plants, and waste-to-energy power plants, the heat from extracted steam extracted from the steam turbine of a thermal power plant is used as the heat source for the reboiler. Therefore, downstream of the point where the steam is extracted from the steam turbine, the flow rate of steam circulating in the steam turbine decreases, and consequently, the amount of electricity generated decreases. This presents a challenge in terms of reduced power generation.

[0011] Incidentally, there is a demand to stop power generation when there is a surplus of electricity, such as at night, as power generation is unnecessary. However, in coal-fired power plants, biomass-fired power plants, and waste-to-energy power plants, the coal boilers, biomass boilers, and waste-to-energy boilers, respectively, take a long time to restart once stopped, so they cannot be shut down, and instead, fuel is consumed, increasing the surplus electricity. Therefore, there is a challenge in effectively utilizing the surplus electricity that is currently being wasted.

[0012] The problem that this invention aims to solve is to provide a thermal power generation system that can suppress the decrease in power generation when power generation is not being suppressed by using the energy generated by a boiler while power generation is being suppressed. [Means for solving the problem]

[0013] The thermal power generation system according to this embodiment comprises a combustion boiler, a steam turbine, a generator, a condenser, a pump, a carbon dioxide recovery device, and a thermal storage tank. The combustion boiler heats the transported water by burning it with a fuel containing carbon atoms to generate steam. The steam turbine is rotationally driven using the steam flowing out of the combustion boiler. The generator is driven using the driving force of the steam turbine. The condenser cools the exhaust from the steam turbine and condenses it into water. The pump circulates the water. The carbon dioxide recovery device recovers carbon dioxide from the combustion exhaust gas discharged by the combustion boiler. The thermal storage tank absorbs and stores the heat contained in the heat source fluid, which is all or part of the steam flowing out of the combustion boiler, or the steam or water circulating inside the combustion boiler. The heat released from the thermal storage tank is used as a heat source for the carbon dioxide recovery device. [Effects of the Invention]

[0014] According to this embodiment, the energy generated by the boiler while power generation is being suppressed can be used to suppress the decrease in power generation when power generation is not being suppressed. [Brief explanation of the drawing]

[0015] [Figure 1] Configuration of a thermal power generation system according to the first embodiment, and a diagram showing the operating state during power surplus. [Figure 2] Configuration of a thermal power generation system according to the first embodiment, and a diagram of the operating state when there is no power surplus. [Figure 3] Configuration of a thermal power generation system according to the second embodiment, and a diagram showing the operating state during power surplus. [Figure 4] Configuration of a thermal power generation system according to the second embodiment, and a diagram of the operating state when there is no power surplus. [Figure 5]Configuration of the thermal power generation system according to the third embodiment and operation state diagram during power surplus. [Figure 6] Configuration of the thermal power generation system according to the third embodiment and operation state diagram when not in power surplus. [Figure 7] Configuration of the thermal power generation system according to the fourth embodiment and operation state diagram during power surplus. [Figure 8] Configuration of the thermal power generation system according to the fourth embodiment and operation state diagram when not in power surplus. [Figure 9] Configuration of the thermal power generation system according to the fifth embodiment and operation state diagram during power surplus. [Figure 10] Configuration of the thermal power generation system according to the fifth embodiment and operation state diagram when not in power surplus. [Figure 11] Configuration of the thermal power generation system according to the sixth embodiment and operation state diagram during power surplus. [Figure 12] Configuration of the thermal power generation system according to the sixth embodiment and operation state diagram when not in power surplus. [Figure 13] Configuration diagram showing a configuration example of the conventional thermal power generation system 200.

Modes for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments do not limit the present invention.

[0017] [[ID=३५]] (First Embodiment) FIG. 1 and FIG. 2 are diagrams showing the configuration and state example of the thermal power generation system 100 according to the first embodiment. FIG. 1 is a diagram showing the operation state when power is in surplus. FIG. 2 is a diagram showing the operation state when not in power surplus. Note that the description of the parts that are the same as the prior art may be omitted with the same numbers. Also, hereinafter, valves are illustrated with an open state in white and a closed state in black.

[0018] As shown in Figures 1 and 2, the thermal power generation system 100 according to this embodiment comprises a combustion boiler 1, a condensate pump 9, a steam turbine 10, valves 14, 18, 25, 27, 28, 29, and 30, a conveyor 20, a heat storage tank 22, a carbon dioxide recovery device 34, a condenser 35, a generator 40, and a control device 50. The control device 50 is optional; if not present, the system is controlled by the operator of the thermal power generation system 100. In other words, this embodiment has a first mode in which the operator controls each component of the thermal power generation system 100, and a second mode in which the control device 50 controls the system. In the following description, the second mode may be described, but the same operation is possible in the first mode as well. The carbon dioxide recovery device 34 also includes an absorption tower 5 and a regeneration tower 6. Furthermore, Figures 1 and 2 illustrate a fuel containing carbon atoms 2, combustion air 3, combustion exhaust gas 4, carbon dioxide 7 and 8 in the absorbent liquid, a first heat source fluid 15, a second heat source fluid 16, water 23, and steam 24.

[0019] As shown in Figures 1 and 2, the combustion boiler 1 is connected to the steam turbine 10 via a valve 30. The steam turbine 10 is connected to the condenser 35, and the condenser 35 is connected to the combustion boiler 1 via a condensate pump 9, thereby forming a circulation flow path. In addition, a portion of the flow path of the combustion boiler 1 branches off and is connected to the regeneration tower 6 of the carbon dioxide recovery device 34 via a valve 14, and the regeneration tower 6 is connected to the condenser 35 via a valve 28. Furthermore, the regeneration tower 6 is connected to the heat storage tank 22 via a conveyor 20 and a valve 29. The heat storage tank 22 is connected to the combustion boiler 1 via a valve 25 and to the regeneration tower 6 of the carbon dioxide recovery device 34 via a valve 18.

[0020] Specifically, the combustion boiler 1 heats water 23 transported from the condensate pump 9 by burning it with a carbon-carbon fuel 2 to generate steam 24. The steam turbine 10 is driven to rotate using the steam 24 flowing out of the combustion boiler 1. The generator 40 generates electricity using the driving force of the steam turbine 10.

[0021] Furthermore, the condenser 35 cools the exhaust from the steam turbine 10, condenses it into water, and circulates it to the combustion boiler 1 via the condensate pump 9. The carbon dioxide recovery system 34 includes an absorption tower 5 that absorbs carbon dioxide into an absorbent liquid, a regeneration tower 6 that releases carbon dioxide from the absorbent liquid supplied from the absorption tower 5, and a reboiler that heats the absorbent liquid in the regeneration tower 6. The heat released from the thermal storage tank 22 is used to heat the absorbent liquid in the reboiler.

[0022] The heat storage tank 22 has a heat storage material capable of absorbing and storing the heat contained in the heat source fluid. For example, the heat source fluid according to this embodiment is steam, steam and water, or all or part of water. That is, the heat storage tank 22 absorbs and stores the heat contained in the heat source fluid, which is all or part of the steam flowing out of the combustion boiler 1, or steam or water circulating inside the combustion boiler 1. The heat source fluid may also be referred to as a heating fluid or heat transfer medium.

[0023] The control device 50 is a device capable of controlling each component within the thermal power generation system 100. Furthermore, the control device 50 can control the opening and closing of valves 14, 16, 27, 28, 29, and 30 in accordance with the operating state of the thermal power generation system 100. In other words, the control device 50 can control the operating state of the heat storage tank 22 to either heat storage operation or heat release operation.

[0024] (Operating conditions when there is a power surplus) Referring to Figure 1, the operating conditions when there is a power surplus will be explained. A power surplus occurs, for example, at night when power demand is low, or during the day when the amount of power generated by solar power is large. The control device 50 opens valves 14, 25, 27, and 28, and closes valves 18, 29, and 30. The control device 50 also stops the steam turbine 10 and the conveyor 20.

[0025] In other words, in the operating state when there is a surplus of electricity, the combustion boiler 1, valve 25, heat storage tank 22, valve 27, valve 28, condenser 35, and condensate pump 9 constitute a circulation path through which the heat source fluid flows. In addition, a portion of the flow path of the combustion boiler 1 constitutes a circulation path through which the heat source fluid flows through valve 14, the regeneration tower 6 of the carbon dioxide recovery device 34, valve 28, condenser 35, and condensate pump 9. These circulation paths merge at valve 28, condenser 35, condensate pump 9, and a portion of the flow path of the combustion boiler 1. Thus, these circulation paths partially overlap.

[0026] The control device 50 stores heat from the heat source fluid in the heat storage tank 22, and at the same time, it executes control to transfer heat from the heat source fluid to the carbon dioxide recovery device 34 for use as a heat source for the carbon dioxide recovery device 34. At this time, the control device 50 executes control to extract the first heat source fluid 15 flowing into the carbon dioxide recovery device 34 from steam or water circulating inside the combustion boiler 1, and to make the heat source fluid flowing into the heat storage tank 22 the steam 24 flowing out of the combustion boiler 1. In other words, when performing heat storage operation, the control device 50 stores heat from the steam 24, which is the heat source fluid, in the heat storage tank 22, and at the same time, it executes control to supply heat from the first heat source fluid 15 to the carbon dioxide recovery device 34 for use as a heat source for the carbon dioxide recovery device 34. Furthermore, when the heat storage tank 22 is operating, the control device 50 controls the flow of the heat source fluid discharged from the heat storage tank 22 into the combustion boiler 1, and also controls the flow of the heat source fluid discharged from the carbon dioxide recovery device 34 into the combustion boiler 1.

[0027] More specifically, steam / water flows through the combustion boiler 1 while being heated and its temperature rising. At this time, a desired amount of steam / water is diverted from the combustion boiler 1 via a valve 14 and flows into the carbon dioxide recovery device 34 as the first heat source fluid 15 via the valve 14. The heat source temperature used in the carbon dioxide recovery device 34 is lower than the temperature of the fluid flowing out of the combustion boiler 1. Therefore, temperature control is made possible by diverting a desired amount of steam / water from the combustion boiler 1 via a valve 14 as the first heat source fluid 15. In this way, by diverting steam / water from the heating flow path of the combustion boiler 1 via a valve 14, it is possible to supply steam / water within the desired temperature range to the carbon dioxide recovery device 34.

[0028] The steam / water that remains in the combustion boiler 1 without being diverted flows out of the combustion boiler 1 as steam 24 and flows into the heat storage tank 22 via valve 25. Meanwhile, the first heat source fluid 15 that flows into the carbon dioxide recovery device 34 flows into the regeneration tower 6 of the carbon dioxide recovery device 34, transferring heat to the heating of the absorbent liquid in the reboiler, and its temperature decreases. At this time, if the first heat source fluid 15 is steam, the cooled steam may change phase and turn into water as it releases heat. In addition, carbon dioxide 8 is released from the absorbent liquid heated in the regeneration tower 6. The absorbent liquid that has released carbon dioxide 8 and returned to its original state flows into the absorption tower 5.

[0029] The steam 24 that flows into the heat storage tank 22 via the valve 25 heats the heat storage material inside the heat storage tank 22, causing its temperature to drop. In other words, the heat storage tank 22 absorbs heat from the heat source fluid, the steam 24, and stores heat. At this time, the steam 24, whose temperature has dropped, may undergo a phase change and turn into water as it releases heat. In this embodiment, when it is stated that water, steam, etc., may undergo a phase change, it means that there will be no disruption to the operation of the thermal power generation system 100.

[0030] Furthermore, the heat storage material in the heat storage tank 22 may be, for example, a latent heat storage material. In this case, even if the temperature of the steam 24 is too high, it will be stored at an appropriate temperature as a heat source.

[0031] The steam or water converted from the steam that flows out of the carbon dioxide recovery device 34 and the steam or water converted from the steam that flows out of the heat storage tank 22 and passes through the valve 27 merge and flow into the condenser 35 via the valve 28. The water 23 condensed in the condenser 35 is then transported back to the combustion boiler 1 by the condensate pump 9 and circulated.

[0032] The control device 50 can adjust the flow rate ratio of the first heat source fluid 15 to the steam 24 by adjusting the opening of valves 14, 25, and 27. In this way, the steam / water heated in the combustion boiler 1 is used as a heat source as the first heat source fluid 15 in the carbon dioxide recovery device 34, and heat is stored in the heat storage tank 22. When the heat storage tank 22 reaches its maximum heat storage capacity and it is not possible to increase the amount of heat supplied to the carbon dioxide recovery device 34, the control device 50 opens valve 30 to operate the steam turbine 10. As a result, the steam 24 is split into steam for the steam turbine 10 and steam for other uses. In this case as well, the control device 50 can adjust the flow rate ratio by adjusting the opening of valves 25, 30, etc. Thus, the flow path of the steam 24 flowing out of the combustion boiler 1 can be branched into a flow path that flows into the steam turbine 10 and a flow path that does not flow into the steam turbine 10 but flows into the heat storage tank 22 or the carbon dioxide recovery device 34. The control device 50 performs control to prevent the flow of steam 24 to the steam turbine 10 when there is a power surplus.

[0033] (Operating state when there is no surplus power) Next, referring to Figure 2, the operating state when there is no surplus power will be explained. The control device 50 opens valves 18, 29, and 30, closes valves 14, 25, 27, and 28, and operates the steam turbine 10 and the conveyor 20.

[0034] In other words, in operating conditions where there is no surplus electricity, the combustion boiler 1, valve 30, steam turbine 10, condenser 35, and condensate pump 9 constitute a circulation path through which the heat source fluid flows. Furthermore, the regeneration tower 6, conveyor 20, valve 29, thermal storage tank 22, and valve 16 of the carbon dioxide recovery device 34 also constitute a circulation path through which the heat source fluid flows. Specifically, when the thermal storage tank 22 is performing heat release operation, the control device 50 circulates the heat transfer medium (heat source fluid) between the thermal storage tank 22 and the carbon dioxide recovery device 34, thereby transferring heat from the thermal storage tank 22 to the carbon dioxide recovery device 34. The heat transfer medium is the same substance that flows through the combustion boiler 1, and a portion of the flow path of the heat transfer medium during thermal storage operation and during heat release operation overlaps with the condenser 35, condensate pump 9, and combustion boiler 1.

[0035] More specifically, the steam or water converted from the steam, transported by the conveyor 20, flows into the heat storage tank 22 via the valve 29. The steam or water converted from the steam that flows into the heat storage tank 22 is heated by the heat released from the heat storage material in the heat storage tank 22, causing its temperature to rise. If water flows in, the water's temperature will rise and some or all of it may turn into steam.

[0036] The steam / water discharged from the heat storage tank 22 becomes a second heat source fluid 16 at a temperature suitable for use as a heat source, and flows into the carbon dioxide recovery device 34 via the valve 16, where heat is transferred and the temperature decreases. In other words, since a latent heat storage material is used as the heat storage material in the heat storage tank 22, the second heat source fluid 16 is generated within the upper temperature limit of the latent heat storage material. In this way, the control device 50 can perform heat release operation of the heat storage tank 22 when there is no power surplus, and supply the heat released from the heat storage tank 22 to the carbon dioxide recovery device 34 for use as a heat source for the carbon dioxide recovery device 34.

[0037] The first heat source fluid 15 that flows into the carbon dioxide capture device 34 flows into the regeneration tower 6 of the carbon dioxide capture device 34, where it transfers heat to the absorbent liquid and its temperature decreases. At this time, if the second heat source fluid 16 is steam, some or all of the cooled steam may be converted into water. Also, carbon dioxide 8 is released from the absorbent liquid heated in the regeneration tower 6. The absorbent liquid, having released the carbon dioxide 8 and returned to its original state, flows into the absorption tower 5.

[0038] The second heat source fluid 16 discharged from the carbon dioxide capture device 34 flows into the conveyor 20 and circulates. The control device 50 adjusts the flow rate of the second heat source fluid 16 using the output of the conveyor 20 and the opening of valves 29, etc. Furthermore, the second heat source fluid 16 heated in the heat storage tank 22 is used as a heat source for the carbon dioxide capture device 34.

[0039] Thus, whether there is a surplus of electricity or not, the heat source of the carbon dioxide capture device 34 is not the extracted steam 11 from the steam turbine 10 (see Figure 13) as in conventional technology. Therefore, the steam flow rate to the steam turbine 10 does not decrease, and the decrease in the power output of the generator 40 is suppressed. Furthermore, when there is a surplus of electricity, the thermal energy that would conventionally be wasted into the outside world is stored in the heat storage tank 22, enabling its effective utilization. In addition, if it becomes necessary to maintain the heat storage state of the heat storage tank 22 for a long period of time, the valves 18, 25, 27, and 29 can be closed to maintain the heat storage state for an extended period.

[0040] In this way, a heat storage tank 22 is configured to absorb and store the heat contained in the heat source fluid, which is all or part of the steam flowing out of the combustion boiler 1, or the steam or water circulating inside the combustion boiler 1. The heat released from the heat storage tank 22 is used as a heat source for the carbon dioxide recovery device 34. This makes it possible to store heat in the heat storage tank 22 when there is a surplus of electricity, and to use the heat released from the heat storage tank 22 as a heat source for the carbon dioxide recovery device 34 when there is no surplus of electricity. As can be seen from this, it is possible to store and release heat in the heat storage tank 22 by utilizing the time difference between when there is a surplus of electricity and when there is no surplus of electricity, and it becomes possible to generate electricity with the generator 40 without reducing the amount of steam used to drive the steam turbine 10. As a result, the energy generated by the combustion boiler 1 when the generator 40 is not generating electricity can be used to suppress the decrease in the amount of electricity generated by the generator 40 when there is no surplus of electricity.

[0041] In this embodiment, heat is stored when there is a surplus of electricity, but this is not limited to that. For example, heat may be stored when there is no surplus of electricity. In this case as well, there will be no interference with the operation of the thermal power generation system 100, and no abnormality will occur in the system. Also, in this embodiment, heat is released both when there is a surplus of electricity and when there is no surplus, but this is not limited to that. For example, even if heat is not released when there is a surplus of electricity, or if heat is not released when there is no surplus of electricity, there will be no interference with the operation of the thermal power generation system 100, and no abnormality will occur in the thermal power generation system 100. In particular, in this embodiment, compared to embodiments 4 and 5 described later, the temperature of the steam / water flowing into the heat storage tank 22 and the carbon dioxide recovery device 34 will be close during heat storage operation, but the flow rates can be made different. For this reason, it is suitable when such operating conditions are desired.

[0042] As described above, according to this embodiment, a heat storage tank 22 is configured to absorb and store the heat contained in the heat source fluid, which is all or part of the steam flowing out of the combustion boiler 1, or the steam or water circulating inside the combustion boiler 1. This makes it possible to store heat in the heat storage tank 22 when the generator 40 is stopped, and to use the heat stored in the heat storage tank 22 as a heat source for the carbon dioxide recovery device 34 when the generator 40 is running. In this way, even when the combustion boiler 1 cannot be stopped, the excess heat generated by the combustion boiler 1 can be stored in the heat storage tank 22 and used as a heat source for the carbon dioxide recovery device 34 when the generator 40 is running. Therefore, it is not necessary to use the amount of heat generated by the combustion boiler 1 when the generator 40 is running as a heat source for the carbon dioxide recovery device 34, and the decrease in the power output of the generator 40 can be suppressed.

[0043] (Second Embodiment) The thermal power generation system 100a according to the second embodiment differs from the thermal power generation system 100 according to the first embodiment in that it has a channel that branches off from the distribution channel between the combustion boiler 1 and the condensate pump 9 to the carbon dioxide recovery device 34. The differences from the thermal power generation system 100 according to the first embodiment will be explained below.

[0044] Figures 3 and 4 show the configuration and state examples of the thermal power generation system 100a according to the second embodiment. Figure 3 shows the operating state when there is a power surplus. Figure 4 shows the operating state when there is no power surplus.

[0045] (Operating conditions when there is a power surplus) Referring to Figure 3, the operating state when there is a power surplus will be explained. The control device 50 opens valves 13, 25, 26, 27, and 28, closes valves 29 and 30, and stops the steam turbine 10 and the conveyor 20.

[0046] In other words, in operating conditions where there is a surplus of electricity, the combustion boiler 1, valves 25 and 26, the heat storage tank 22, valves 27 and 28, the condenser 35, and the condensate pump 9 constitute a circulation path through which the heat source fluid flows. Furthermore, the branch flow path between the combustion boiler 1 and the condensate pump 9 constitutes a circulation path through which the heat source fluid flows through valve 13, the regeneration tower 6 of the carbon dioxide recovery device 34, valve 28, the condenser 35, and the condensate pump 9. These circulation paths merge at valve 28, the condenser 35, the condensate pump 9, and a portion of the flow path of the combustion boiler 1. In addition, the branch flow path between valve 25 and valve 26 is in communication with the flow path between valve 13 and the regeneration tower 6 of the carbon dioxide recovery device 34. Thus, the flow path of steam 24 flowing out of the combustion boiler 1 can be branched into a flow path that flows into the steam turbine 10 and a flow path that does not flow into the steam turbine 10 but flows into the heat storage tank 22 or the carbon dioxide recovery device 34.

[0047] The control device 50 stores heat from the heat source fluid, steam 24, in the heat storage tank 22. At the same time, when transferring heat from the steam 24 to the carbon dioxide recovery device 34 for use as a heat source for the carbon dioxide recovery device 34, it branches the steam 24 through the distribution channel between valve 25 and valve 26, allowing it to flow into the carbon dioxide recovery device 34 and the heat storage tank 22 respectively. It also controls the flow of the heat source fluids that have flowed out of the carbon dioxide recovery device 34 and the heat storage tank 22 into the combustion boiler 1. Furthermore, during the heat storage operation of the heat storage tank 22, the control device 50 controls the flow of a fluid into the carbon dioxide recovery device 34 that is a mixture of the heat source fluid, steam 24, and branched water 12 that has been branched from the water 23 flowing into the combustion boiler 1 via valve 13.

[0048] More specifically, the steam 24 flowing out of the combustion boiler 1 branches into two streams: one that passes through valve 25 and goes to the carbon dioxide recovery device 34, and the other that passes through valve 26 and goes to the heat storage tank 22. The water 23 being transported by the condensate pump 9 branches off before entering the combustion boiler 1, becoming branched water 12. After passing through valve 13, the branched water 12 merges with the steam that passes through valve 25 and goes to the carbon dioxide recovery device 34, becoming a third heat source fluid 21 that flows into the carbon dioxide recovery device 34.

[0049] The control device 50 determines that the temperature of the heat source used in the carbon dioxide recovery device 34 is too high if the steam 24 flows out of the combustion boiler 1 is mixed with the branch water 12 to bring the third heat source fluid 21 to an appropriate temperature. The control device 50 adjusts the flow rate ratio of the water 23 flowing into the combustion boiler 1 and the branch water 12 by adjusting the opening of the valve 13.

[0050] As described above, the heat storage material in the heat storage tank 22 can be made of a latent heat storage material whose phase change temperature is the appropriate temperature for use as a heat source in the carbon dioxide recovery device 34. In this case, even if the temperature of the steam 24 is too high, heat will be stored at an appropriate temperature for the heat source. For this reason, the heat storage tank 22 can store heat even when the temperature of the third heat source fluid 21 is higher.

[0051] The remaining steam / water from the combustion boiler 1 flows into the heat storage tank 22 via valve 26. The steam / water heated in the combustion boiler 1 is used as a heat source in the carbon dioxide recovery device 34 as the third heat source fluid 21, and heat is stored in the heat storage tank 22. In this way, when the heat storage operation of the heat storage tank 22 is performed, the control device 50 stores heat from the steam 24, which is the heat source fluid, in the heat storage tank 22, and also supplies heat from the steam 24 to the carbon dioxide recovery device 34 for use as a heat source for the carbon dioxide recovery device 34. In this case, it is possible to bring the third heat source fluid 21 to an appropriate temperature by mixing in branch water 12 that has been bypassed from the combustion boiler 1.

[0052] (Operating state when there is no surplus power) Next, referring to Figure 4, the operating state when there is no surplus power will be explained. The control device 50 opens valves 26, 29, and 30, closes valves 13, 25, 27, and 28, and operates the steam turbine 10 and the conveyor 20.

[0053] In other words, in operating conditions where there is no surplus electricity, the combustion boiler 1, valve 30, steam turbine 10, condenser 35, and condensate pump 9 constitute a circulation path through which the heat source fluid flows. Additionally, the regeneration tower 6, conveyor 20, valve 29, thermal storage tank 22, and valve 25 of the carbon dioxide recovery device 34 also constitute a circulation path through which the heat source fluid flows. When the control device 50 transfers the heat from the heat source fluid to the carbon dioxide recovery device 34 for use, it controls the flow of the heat source fluid to the carbon dioxide recovery device 34 and the flow of the heat source fluid that has flowed out of the carbon dioxide recovery device 34 back into the combustion boiler 1.

[0054] More specifically, the steam or water converted from the steam, transported by the conveyor 20, flows into the heat storage tank 22 via the valve 29. The steam or water converted from the steam that flows into the heat storage tank 22 is heated by the heat released from the heat storage material in the heat storage tank 22, causing its temperature to rise. If water flows in, some or all of the water may be converted into steam. The steam that flows out of the heat storage tank 22 becomes the third heat source fluid 21, flows into the carbon dioxide recovery device 34 via the valve 25, transfers heat, and its temperature decreases. At this time, some or all of the steam may be converted into water.

[0055] The third heat source fluid 21 that flows out of the carbon dioxide capture device 34 flows into the conveyor 20 and circulates. The control device 50 adjusts the flow rate of the third heat source fluid 21 using the output of the conveyor 20 and the opening of valves 29, etc.

[0056] Thus, the third heat source fluid 21 heated in the heat storage tank 22 is used as a heat source in the carbon dioxide recovery device 34. As a result, the thermal power generation system 100a according to this embodiment can obtain the same effects as the thermal power generation system 100 according to the first embodiment.

[0057] In the thermal power generation system 100 according to the first embodiment, during thermal storage operation, an appropriate amount of steam / water is diverted from the middle of the combustion boiler 1 and flowed into the carbon dioxide recovery device 34 as the first heat source fluid 15. This requires modification of the combustion boiler 1 and makes it difficult to control the temperature of the first heat source fluid 15 (see Figures 1 and 2). In contrast, in the thermal power generation system 100a according to this embodiment, there is no need to modify the combustion boiler 1, and it becomes possible to add the branched water 12 to the steam 24. This makes temperature control easier.

[0058] Furthermore, if the heat storage state of the heat storage tank 22 is to be maintained for a long period of time, valves 26, 27, and 29 are closed. Similar to the thermal power generation system 100 according to the first embodiment, the temperature of the steam / water flowing into the heat storage tank 22 and the carbon dioxide recovery device 34 in this embodiment is close, but the flow rates can be made different. For this reason, it is suitable when such operating conditions are desired.

[0059] As described above, according to this embodiment, a channel is configured to divert branched water 12 from the branch channel between the combustion boiler 1 and the condensate pump 9 to the carbon dioxide recovery device 34, and a third heat source fluid 21, which is obtained by mixing the branched water 12 with steam 24 flowing through the branch channel between valve 25 and valve 26, is supplied to the carbon dioxide recovery device 34. This makes it possible to store heat in the heat storage tank 22 with the steam 24 flowing through valve 26, and to mix the water 12 that has not been heated by the combustion boiler 1 with the steam 24 flowing through the branch channel between valve 25 and valve 26, thereby making it possible to bring the third heat source fluid 21 to an appropriate temperature.

[0060] (Third embodiment) The thermal power generation system 100c according to the third embodiment differs from the thermal power generation system 100b according to the second embodiment in that it further has a flow path for supplying the heat source fluid discharged from the steam turbine 10 when there is no surplus electricity to the carbon dioxide recovery device 34. The differences from the thermal power generation system 100b according to the second embodiment will be explained below.

[0061] Figures 5 and 6 show the configuration and state examples of the thermal power generation system 100c according to the third embodiment. Figure 5 shows the operating state when there is a power surplus. Figure 6 shows the operating state when there is no power surplus.

[0062] (Operating conditions when there is a power surplus) Referring to Figure 5, the operating state when there is a power surplus will be explained. The control device 50 opens valves 13, 25, 26, 27, and 28, closes valves 17, 29, and 30, and stops the steam turbine 10 and the conveyor 20.

[0063] The operating state when there is a surplus of electricity is equivalent to that of the thermal power generation system 100b according to the second embodiment. That is, in the operating state when there is a surplus of electricity, the combustion boiler 1, valves 25 and 26, heat storage tank 22, valves 27 and 28, condenser 35, and condensate pump 9 constitute a circulation path through which the thermal fluid flows. In addition, the branch flow path between the combustion boiler 1 and the condensate pump 9 constitutes a circulation path through which the thermal fluid flows through valve 13, the regeneration tower 6 of the carbon dioxide recovery device 34, valve 28, condenser 35, and condensate pump 9. These circulation paths merge at valve 28, condenser 35, condensate pump 9, and a portion of the flow path of the combustion boiler 1. Furthermore, the branch flow path between valve 25 and valve 26 is in communication with the flow path between valve 13 and the regeneration tower 6 of the carbon dioxide recovery device 34.

[0064] The heat storage tank 22 in this embodiment differs from the second embodiment in that it has a solid sensible heat storage material such as rock, and the heat storage temperature is high. The solid sensible heat storage material can also store heat when the heat source temperature is even higher.

[0065] (Operating state when there is no surplus power) Next, referring to Figure 6, the operating state when there is no surplus power will be explained. The control device 50 opens valves 17, 26, 29, and 30, closes valves 13, 25, 27, and 28, and operates the steam turbine 10 and the conveyor 20.

[0066] In other words, in operating conditions where there is no surplus electricity, the combustion boiler 1, valve 30, steam turbine 10, condenser 35, and condensate pump 9 constitute a circulation path through which the heat source fluid flows. Furthermore, the flow path through the regeneration tower 6, conveyor 20, valve 29, thermal storage tank 22, and valve 26 of the carbon dioxide recovery device 34 merges with the flow path through the regeneration tower 6, conveyor 20, and valve 27 of the carbon dioxide recovery device 34 to form a circulation path through which the heat source fluid flows into the regeneration tower 6 of the carbon dioxide recovery device 34.

[0067] The control device 50, during the heat dissipation operation of the heat storage tank 22, splits the fluid heading to the heat storage tank 22, allowing one branch to flow through the heat storage tank 22 and the other to bypass the heat storage tank 22, before merging them and flowing them into the carbon dioxide recovery device 34. More specifically, the steam or water converted from steam transported by the conveyor 20 is split into a fluid that passes through valve 29 and a fluid that passes through valve 17. The fluid that passes through valve 29 flows into the heat storage tank 22 and is heated by the heat dissipation from the heat storage material in the heat storage tank 22, causing its temperature to rise. If water flows in, some or all of the water may be converted into steam.

[0068] The fluid that passes through valve 17 bypasses the heat storage tank 22 and then merges with the steam / water that has flowed out of the heat storage tank 22 to become the third heat source fluid 21. In this embodiment, the heat is stored at a temperature that is too high for the heat source temperature, so by merging it with the fluid that has bypassed the heat storage tank 22, the temperature of the third heat source fluid 21 is lowered to a temperature suitable for the carbon dioxide recovery device 34.

[0069] The control device 50 adjusts the flow rate of the third heat source fluid 21 using the output of the conveyor 20 and the opening of valves 29, etc., and adjusts the temperature using the opening of valves 29 and 17. The third heat source fluid 21 heated in the heat storage tank 22 is used as a heat source in the carbon dioxide recovery device 34.

[0070] Thus, the thermal power generation system 100c according to this embodiment can achieve the same effects as the thermal power generation systems 100a and 100b according to embodiments 1 and 2. In the thermal power generation system 100b according to embodiment 2, a latent heat storage material was used in the heat storage tank 22. However, if a solid sensible heat storage material were used, for example, the temperature of the third heat source fluid 21 would be too high, exceeding the allowable range of the carbon dioxide recovery device 34. Furthermore, in the thermal power generation system 100b according to embodiment 2 (see Figure 4), if branch water 12 were mixed into the downstream fluid of the heat storage tank 22 via the valve 13, it would be possible to lower the temperature of the third heat source fluid 21. However, in that case, the flow rate of steam 24 flowing into the steam turbine 10 would decrease, and the amount of power generated by the generator 40 would decrease.

[0071] In contrast, the thermal power generation system 100c according to this embodiment has a first flow path that heats the heat source fluid in the heat storage tank 22 via valve 29, the heat storage tank 22, and valve 26 when there is no surplus power, and a second flow path that bypasses the heat storage tank 22 via valve 13. As a result, the control device 50 can adjust the flow rate of the third heat source fluid 21 with the output of the conveyor 20 and the opening of valve 29, etc., and adjust the temperature with the opening of valve 29 and valve 17. Therefore, temperature control and flow rate adjustment of the third heat source fluid 21 can be made simpler and more accurate, and even if a solid sensible heat storage material is used in the heat storage tank 22, the temperature of the third heat source fluid 21 can be adjusted to a temperature range suitable for the carbon dioxide recovery device 34.

[0072] Furthermore, when there is no surplus electricity, the heat source fluid flowing in through the valve 28 is supplied from the downstream side of the steam turbine 10, so it does not affect the flow rate of steam 24 flowing into the steam turbine 10, and thus the decrease in the power output of the generator 40 can be suppressed.

[0073] Furthermore, if the heat storage state of the heat storage tank 22 is to be maintained for a long period of time, it is possible to close valves 17, 26, 27, and 29 to maintain the state for an extended period. Moreover, in the thermal power generation system 100b according to this embodiment, similar to the thermal power generation systems 100 and 100a according to the first and second embodiments, the temperatures of the steam / water flowing into the heat storage tank 22 and the carbon dioxide recovery device 34 are close, but the flow rates can be made different. For this reason, it is suitable when such operating conditions are desired.

[0074] As described above, according to this embodiment, when dissipating heat from the heat storage tank 22, a first flow path is configured that goes from the conveyor 20 through valve 29, the heat storage tank 22, and valve 26, passing through the heat storage tank 22, and a second flow path that bypasses the heat storage tank 22 via valve 17 from the conveyor 20. By adjusting the flow rates of the first and second flow paths, it becomes possible to adjust the temperature of the heat source fluid flowing into the carbon dioxide recovery device 34 with greater precision.

[0075] (Fourth embodiment) The thermal power generation system 100c according to the fourth embodiment differs from the thermal power generation system 100a according to the second embodiment in that, when storing heat in the heat storage tank 22, it uses a heat source fluid flowing downstream of the carbon dioxide recovery device 34 for heat storage. The differences from the thermal power generation system 100a according to the second embodiment will be explained below.

[0076] Figures 7 and 8 show the configuration and state examples of the thermal power generation system 100c according to the fourth embodiment. Figure 7 shows the operating state when there is a power surplus. Figure 8 shows the operating state when there is no power surplus.

[0077] (Operating conditions when there is a power surplus) Referring to Figure 7, the operating state when there is a surplus of power will be explained. The control device 50 opens valves 13, 25, 26, 27, and 28, closes valves 29, 30, and 31, and stops the steam turbine 10 and the conveyor 20.

[0078] In other words, in operating conditions where there is a surplus of electricity, the combustion boiler 1, valve 25, the regeneration tower 6 of the carbon dioxide recovery device 34, valve 26, the heat storage tank 22, valves 27 and 28, the condenser 35, and the condensate pump 9 constitute a circulation path through which the thermal fluid flows. In addition, the branch channel between the combustion boiler 1 and the condensate pump 9 merges downstream of valve 25 via valve 13.

[0079] The control device 50 stores heat from the heat source fluid in the heat storage tank 22, and at the same time, when transferring heat from the heat storage tank 22 to the carbon dioxide recovery device 34 for use as a heat source for the carbon dioxide recovery device 34, it controls the flow of the heat source fluid into the heat storage tank 22, the flow of the heat source fluid that has flowed out of the heat storage tank 22 into the carbon dioxide recovery device 34, and the flow of the heat source fluid that has flowed out of the carbon dioxide recovery device 34 into the combustion boiler 1. More specifically, the steam 24 that has flowed out of the combustion boiler 1 passes through valve 25. The water 23 being transported by the condensate pump 9 is partially branched before flowing into the combustion boiler 1, becoming branched water 12. After passing through valve 13, the branched water 12 passes through valve 25 and merges with the steam 24 heading towards the carbon dioxide recovery device 34, becoming a third heat source fluid 21 and flowing into the carbon dioxide recovery device 34.

[0080] The temperature of the heat source used in the carbon dioxide recovery device 34 is too high if it is the temperature of the water flowing out of the combustion boiler 1. By mixing in the branch water 12, it is possible to bring the third heat source fluid 21 to an appropriate temperature. The control device 50 adjusts the flow rate ratio of the water 23 to the water flowing into the combustion boiler 1 and the branch water 12 by adjusting the opening of the valve 13.

[0081] The third heat source fluid 21 transfers heat to the carbon dioxide recovery device 34, causing its temperature to decrease. The steam that flows out of the carbon dioxide recovery device 34 flows into the heat storage tank 22. The steam that flows into the heat storage tank 22 heats the heat storage material inside the heat storage tank 22, causing its temperature to decrease. At this time, some or all of the steam may be converted into water. In this way, the third heat source fluid 21, which has passed through the carbon dioxide recovery device 34, flows into the heat storage tank 22. As described above, since the third heat source fluid 21 is already adjusted to an appropriate temperature for the carbon dioxide recovery device 34, even if the heat storage material is a latent heat storage material or a solid sensible heat storage material, a state in which the heat storage temperature is too high for the heat storage material is suppressed.

[0082] Steam or water converted from steam that flows out of the heat storage tank 22 flows into the condenser 35, and is then transported to the combustion boiler 1 by the condensate pump 9 and circulated. The steam 24 is used as a heat source as the third heat source fluid 21 in the carbon dioxide recovery device 34, and then heat is stored in the heat storage tank 22. Subsequent operating conditions are equivalent to those of the thermal power generation systems 100, 100a, and 100b according to the first to third embodiments.

[0083] Furthermore, the control device 50 can open the valve 30 and operate the steam turbine 10 when the heat storage tank 22 has reached its maximum heat storage capacity and the amount of heat supplied to the carbon dioxide recovery device 34 cannot be increased further. The steam 24 from the combustion boiler 1 is split into steam for the steam turbine 10 and steam for other uses, and the control device 50 adjusts the flow rate ratio by adjusting the opening of the valve 25, etc.

[0084] (Operating state when there is no surplus power) Next, referring to Figure 8, the operating state when there is no surplus power will be explained. The control device 50 closes valves 13, 25, 26, and 28 and operates the steam turbine 10 and the conveyor 20.

[0085] In other words, in operating conditions where there is no surplus electricity, the combustion boiler 1, valve 30, steam turbine 10, condenser 35, and condensate pump 9 constitute a circulation path through which the heat source fluid flows. Additionally, the carbon dioxide recovery device 34 consists of a regeneration tower 6, valve 31, conveyor 20, valve 27, thermal storage tank 22, and valve 29, all of which constitute a circulation path.

[0086] More specifically, the steam or water transformed from steam transported by the conveyor 20 flows into the heat storage tank 22. The steam or water transformed from steam that flows into the heat storage tank 22 is heated by the heat released from the heat storage material in the heat storage tank 22, causing its temperature to rise. If water is introduced, some or all of the water may be transformed into steam. As described above, the heat storage material in the heat storage tank 22 is stored in a way that avoids a state where the heat storage temperature is too high relative to the heat storage material. Therefore, even if the heat storage material in the heat storage tank 22 is a latent heat storage material or a solid sensible heat storage material, the heat storage temperature will not be too high, and temperature control such as that in the thermal power generation system 100b according to the third embodiment (see Figure 6) is unnecessary.

[0087] The steam discharged from the heat storage tank 22 becomes the third heat source fluid 21, flows into the carbon dioxide recovery device 34, transfers heat, and cools down. At this time, some or all of the steam may be converted into water. The third heat source fluid 21 flows into the conveyor 20 via the valve 31 and circulates. The control device 50 can adjust the flow rate of the third heat source fluid 21 using the output of the conveyor 20 and the opening of valves 27, etc. The third heat source fluid 21 is used as a heat source in the carbon dioxide recovery device 34. Furthermore, if the heat storage state of the heat storage tank 22 is to be maintained for a long period of time, valves 26, 27, and 29 can be closed to maintain it. In this way, it is possible to obtain the same effects as the thermal power generation systems 100 and 100a according to the first and second embodiments. Furthermore, the thermal power generation system 100c according to the fourth embodiment is suitable for cases where such conditions are desired, as it has the same steam / water flow rates to the heat storage tank 22 and the carbon dioxide recovery device 34 as the thermal power generation systems 100, 100a, 100b, and 100d according to the first to third and fifth embodiments described later, but the inflow temperature to the carbon dioxide recovery device 34 is higher than the inflow temperature to the heat storage tank 22.

[0088] As described above, according to this embodiment, the heat storage tank 22 is used to store heat using a heat source fluid whose temperature has been adjusted before it flows into the carbon dioxide recovery device 34. As a result, since the heat source fluid whose temperature has been adjusted before it flows into the heat storage tank 22, it is possible to store heat without the storage temperature being too high for the heat storage material in the heat storage tank 22. Therefore, when the heat source fluid is heated by the heat dissipation from the heat storage tank 22, even if the heat storage material in the heat storage tank 22 is a latent heat storage material or a solid sensible heat storage material, the storage temperature will not be too high, making it possible to eliminate the need to adjust the temperature of the heat source fluid that flows out of the heat storage tank 22.

[0089] (Fifth embodiment) The thermal power generation system 100d according to the fifth embodiment differs from the thermal power generation system 100a according to the second embodiment in that, when storing heat in the heat storage tank 22, all of the heat source fluid that has flowed through the heat storage tank 22 is fed into the carbon dioxide recovery device 34 after temperature adjustment. The differences from the thermal power generation system 100a according to the second embodiment will be explained below.

[0090] Figures 9 and 10 show the configuration and state examples of the thermal power generation system 100c according to the fifth embodiment. Figure 9 shows the operating state when there is a power surplus. Figure 10 shows the operating state when there is no power surplus.

[0091] (Operating conditions when there is a power surplus) Referring to Figure 9, the operating state when there is a power surplus will be explained. The control device 50 opens valves 13, 25, 27, and 29, closes valves 26, 28, and 30, and stops the steam turbine 10 and the conveyor 20.

[0092] In other words, in operating conditions where there is a surplus of electricity, the combustion boiler 1, valve 25, heat storage tank 22, valve 27, regeneration tower 6 of the carbon dioxide recovery device 34, valve 29, condenser 35, and condensate pump 9 constitute a circulation path through which the thermal fluid flows. In addition, the branch channel between the combustion boiler 1 and the condensate pump 9 merges downstream of valve 25 via valve 13.

[0093] The control device 50 controls the thermal storage tank 22 during thermal storage operation by mixing steam 24, which is the heat source fluid, with branched water 12 that branches off from the water 23 flowing into the combustion boiler 1, and then introducing this fluid into the thermal storage tank 22. The control device 50 then controls the third heat source fluid 21 that has passed through the thermal storage tank 22 to heat the carbon dioxide recovery device 34. More specifically, the steam 24 flowing out of the combustion boiler 1 passes through valve 25. The water 23 being transported by the condensate pump 9 is partially branched before flowing into the combustion boiler 1 to become branched water 12. After passing through valve 13, the branched water 12 passes through valve 25 and merges with the steam 24 heading towards the thermal storage tank 22, and then flows into the thermal storage tank 22. The heat stored in the thermal storage tank 22 is used in the carbon dioxide recovery device 34 during heat release operation, but the heat source temperature is too high at the temperature of the water flowing out of the combustion boiler 1. Therefore, the control device 50 controls the heat storage temperature to prevent it from becoming too high by mixing in the branched water 12.

[0094] Furthermore, the control device 50 adjusts the flow rate ratio of the water 23 flowing into the combustion boiler 1 and the branch water 12 by the opening of the valve 13. The steam flowing into the heat storage tank 22 heats the heat storage material in the heat storage tank 22, causing its temperature to decrease. At this time, some or all of the steam may change into water. The steam / water flowing out of the heat storage tank 22 flows into the carbon dioxide recovery device 34 as a third heat source fluid 21. The third heat source fluid 21 transfers heat to the carbon dioxide recovery device 34, causing its temperature to decrease. At this time, if it is in the state of steam, some or all of it may change into water. The heat source temperature used in the carbon dioxide recovery device 34 is too high at the temperature flowing out of the combustion boiler 1, but this is adjusted by mixing the branch water 12 upstream of the heat storage tank 22. Therefore, the third heat source fluid 21 is at an appropriate temperature for the carbon dioxide recovery device 34. The third heat source fluid 21, having passed through the carbon dioxide recovery unit 34, flows into the condenser 35, and is then transported to the combustion boiler 1 by the condensate pump 9 for circulation. The steam 24 is used as a heat source, the third heat source fluid 21, in the carbon dioxide recovery unit 34 after heat storage is performed in the thermal storage tank 22. Other operating conditions are equivalent to those of the thermal power generation systems 100 to 100c according to the first to fourth embodiments.

[0095] Furthermore, the control device 50 can open the valve 30 and operate the steam turbine 10 when the heat storage tank 22 has reached its maximum heat storage capacity and the amount of heat supplied to the carbon dioxide recovery device 34 cannot be increased further. The steam from the combustion boiler 1 is split into steam for the steam turbine 10 and steam for other uses, and the control device 50 adjusts the flow rate ratio by adjusting the opening of the valve 25, etc.

[0096] (Operating state when there is no surplus power) Next, referring to Figure 10, the operating state when there is no surplus power will be explained. The control device 50 opens valves 25, 27, 29, and 30, closes valves 13, 25, and 29, and operates the steam turbine 10 and the conveyor 20.

[0097] In other words, in operating conditions where there is no surplus electricity, the combustion boiler 1, valve 30, steam turbine 10, condenser 35, and condensate pump 9 constitute a circulation path through which the heat source fluid flows. Additionally, the regeneration tower 6, valve 28, conveyor 20, valve 26, thermal storage tank 22, and valve 27 of the carbon dioxide recovery device 34 constitute a circulation path through which the fluid flows.

[0098] More specifically, the steam or water converted from the steam, transported by the conveyor 20, flows into the heat storage tank 22 via the valve 26. The steam or water converted from the steam that flows into the heat storage tank 22 is heated by the heat released from the heat storage material in the heat storage tank 22, causing its temperature to rise. If water is introduced, some or all of the water may be converted into steam.

[0099] As described above, the heat storage material in the heat storage tank 22 is stored in a way that avoids the storage temperature becoming too high for the heat storage material by mixing it with the branch water 12 during heat storage. Therefore, even if the heat storage material in the heat storage tank 22 is a latent heat storage material or a solid sensible heat storage material, the storage temperature will not become too high, and temperature control such as that in the thermal power generation system 100b according to the third embodiment (see Figure 6) becomes unnecessary.

[0100] The steam discharged from the heat storage tank 22 becomes the third heat source fluid 21, flows into the carbon dioxide recovery device 34, transfers heat, and cools down. At this time, some or all of the steam may be converted into water. The third heat source fluid 21 flows into the conveyor 20 and circulates. The control device 50 adjusts the flow rate of the third heat source fluid 21 using the output of the conveyor 20 and the opening of valves 26, etc. The third heat source fluid 21 is used as a heat source in the carbon dioxide recovery device 34. Furthermore, the control device 50 can close valves 25, 26, and 27 to maintain the heat storage state of the heat storage tank 22 for a long period of time. In this way, it is possible to obtain effects equivalent to those of the thermal power generation systems 100, 100a, and 100c according to the first, second, and fourth embodiments. Furthermore, the thermal power generation system 100d according to the fifth embodiment is suitable for cases where such conditions are desired, as it has the same steam / water flow rates to the thermal storage tank 22 and the carbon dioxide recovery device 34 as the thermal power generation systems 100, 100a, 100b, and 100c according to the first to fourth embodiments, but the inflow temperature to the thermal storage tank 22 is higher than the inflow temperature to the carbon dioxide recovery device 34.

[0101] As explained above, when storing heat in the heat storage tank 22, a flow path is configured to supply water 23 heated by the combustion boiler 1 to the heat storage tank 22, and a flow path is configured to supply water 23 that has bypassed the combustion boiler 1 to the heat storage tank 22, thereby adjusting the temperature of the heat source fluid used for heat storage in the heat storage tank 22. As a result, even when the heat source fluid passing through the heat storage tank 22 is flowed into the carbon dioxide recovery device 34, the temperature of the heat source fluid has already been adjusted, so there is no need to adjust the temperature of the heat source fluid for the carbon dioxide recovery device 34. Furthermore, since the heat storage tank 22 is stored by adjusting the temperature of the heat source fluid, even when the heat source fluid is heated by heat dissipation in the heat storage tank 22 and then flowed into the carbon dioxide recovery device 34, there is no need to adjust the temperature of the heat source fluid for the carbon dioxide recovery device 34.

[0102] (Sixth Embodiment)

[0103] The thermal power generation system 100e according to the sixth embodiment differs from the thermal power generation systems 100 to 100d according to the first to fifth embodiments in that it separates the flow path for storing heat in the heat storage tank 22 from the flow path for releasing heat from the heat storage tank 22. The differences from the thermal power generation systems 100 to 100d according to the first to fifth embodiments will be explained below.

[0104] Figures 11 and 12 show the configuration and state examples of the thermal power generation system 100e according to the sixth embodiment. Figure 11 shows the operating state when there is a power surplus. Figure 12 shows the operating state when there is no power surplus. The regeneration tower 6 of the carbon dioxide recovery device 34 has a first flow path for heating the heat storage tank 22 and a second flow path for heat dissipation from the heat storage tank 22, separated. Similarly, the heat storage tank 22 has a first flow path for heating and a second flow path for heat dissipation, separated.

[0105] (Operating conditions when there is a power surplus) Referring to Figure 9, the operating state when there is a power surplus will be explained. The control device 50 opens valves 13, 19, 25, 26, 27, and 28, closes valves 30, 31, and 32, and stops the steam turbine 10 and the conveyor 20.

[0106] In other words, in operating conditions where there is a surplus of electricity, the combustion boiler 1, valve 25, the first flow path of the regeneration tower 6 of the carbon dioxide recovery device 34, valve 19, the first flow path of the heat storage tank 22, valves 27 and 28, the condenser 35, and the condensate pump 9 constitute the first circulation flow path through which the heat source fluid flows. In addition, the branch flow path between the combustion boiler 1 and the condensate pump 9 merges downstream of valve 25 via valve 13.

[0107] More specifically, the steam 24 flowing out of the combustion boiler 1 passes through valve 25. The water 23 being transported by the condensate pump 9 is partially branched off before flowing into the combustion boiler 1, becoming branched water 12. After passing through valve 13, the branched water 12 passes through valve 25 and merges with the steam 24 heading towards the carbon dioxide recovery device 34, becoming a third heat source fluid 21 and flowing into the first flow path of the carbon dioxide recovery device 34.

[0108] The control device 50 adjusts the temperature of the third heat source fluid 21 to an appropriate level by mixing it with branch water 12, because the temperature of the heat source used in the first flow path of the carbon dioxide recovery device 34 is too high at the temperature of the water flowing out of the combustion boiler 1. The control device 50 can adjust the flow rate ratio of the water 23 to the water flowing into the combustion boiler 1 and the branch water 12 by adjusting the opening of the valve 13.

[0109] The third heat source fluid 21 transfers heat to the carbon dioxide recovery device 34, causing its temperature to decrease. The steam that flows out of the first channel of the carbon dioxide recovery device 34 flows into the first channel of the heat storage tank 22 via the valve 19. The steam that flows into the first channel of the heat storage tank 22 heats the heat storage material in the heat storage tank 22, causing its temperature to decrease. At this time, some or all of the steam may be converted into water. This results in heat storage in the heat storage tank 22, but since the third heat source fluid 21 is regulated to an appropriate temperature for the carbon dioxide recovery device 34, the heat storage temperature is controlled so that it does not become too high, regardless of whether the heat storage material is a latent heat storage material or a solid sensible heat storage material.

[0110] Steam or water converted from steam that flows out of the first flow path of the heat storage tank 22 flows into the condenser 35, and is then transported to the combustion boiler 1 by the condensate pump 9 and circulated. The steam 24 is used as a heat source called the third heat source fluid 21 in the carbon dioxide recovery device 34, and then heat is stored in the heat storage tank 22. Other operating conditions are the same as those of the thermal power generation systems 100, 100a, and 100b described in the first to third.

[0111] Furthermore, the control device 50 can open the valve 30 and operate the steam turbine 10 when the heat storage tank 22 has reached its maximum heat storage capacity and the amount of heat supplied to the carbon dioxide recovery device 34 cannot be increased further. The steam 24 from the combustion boiler 1 is split into steam for the steam turbine 10 and steam for other uses, and the control device 50 adjusts the flow rate ratio by adjusting the opening of the valve 25, etc.

[0112] (Operating state when there is no surplus power) Next, referring to Figure 11, the operating state when there is no surplus power will be explained. The control device 50 opens valves 30, 31, and 32, closes valves 13, 19, 25, 27, and 28, and operates the steam turbine 10 and the conveyor 20.

[0113] In other words, in operating conditions where there is no surplus electricity, the combustion boiler 1, valve 30, steam turbine 10, condenser 35, and condensate pump 9 constitute a circulation path through which the heat source fluid flows. In addition, the second circulation path of the regeneration tower 6 of the carbon dioxide recovery device 34, the conveyor 20, valve 31, the second circulation path of the heat storage tank 22, and valve 32 are also formed.

[0114] More specifically, the heat transfer medium 33 flows into the second flow path of the heat storage tank 22 via the valve 31 by the conveyor 20. The heat transfer medium 33 that flows into the second flow path of the heat storage tank 22 is heated by the heat released from the heat storage material in the heat storage tank 22, and its temperature rises. The heat transfer medium 33 may be a gas or a liquid, and if it is a liquid, it may undergo a phase change to a gas.

[0115] As described above, the heat storage material in the heat storage tank 22 is mixed with branch water 12 before flowing into the carbon dioxide recovery device 34, thereby preventing the heat storage temperature from becoming too high and ensuring proper heat storage. Therefore, even if the heat storage material in the heat storage tank 22 is a latent heat storage material or a solid sensible heat storage material, the heat storage temperature will not become too high, eliminating the need for temperature control as in the thermal power generation system 100b according to the third embodiment (see Figure 6).

[0116] The heat transfer medium 33 that flows out of the second channel of the heat storage tank 22 flows into the second channel of the carbon dioxide recovery device 34, where it transfers heat and its temperature decreases. The heat transfer medium 33 may undergo a phase change to a liquid if it is a gas. The heat transfer medium 33 that flows out of the second channel of the carbon dioxide recovery device 34 flows into the conveyor 20 and circulates. The control device 50 adjusts the flow rate of the heat transfer medium 33 using the output of the conveyor 20 and the opening of valves 31, etc. The heat transfer medium 33 heated in the heat storage tank 22 is used as a heat source in the carbon dioxide recovery device 34. Furthermore, the control device 50 can close valves 19, 27, 31, and 32 to preserve the heat storage state of the heat storage tank 22 for a long period of time. In this way, it is possible to obtain effects equivalent to those of the thermal power generation systems 100, 100a, and 100c according to the first, second, and fourth embodiments.

[0117] As described above, according to this embodiment, the carbon dioxide recovery device 34 and the heat storage tank 22 are configured to separate a first flow path for heating and a second flow path for heat release. This allows the first circulation flow path for heat storage in the heat storage tank 22 and the second circulation flow path for heat release in the heat storage tank 22 to be configured separately. Therefore, the heat transfer medium that transports heat from the heat storage tank 22 to the carbon dioxide recovery device 34 during heat release operation can be a different substance from the working fluid of the steam turbine 10. This makes it possible to use a substance that is more suitable as a heat transfer medium depending on the heat transfer conditions in the carbon dioxide recovery device 34, the heat transfer conditions in the heat storage tank 22, and the transport conditions. (Seventh Embodiment)

[0118] In the thermal power generation system according to the seventh embodiment, the control device 50 according to the first to sixth embodiments operates the combustion boiler 1 at a lower load when there is a power surplus compared to when there is no power surplus. This further suppresses the flow rate of combustion exhaust gas 4 and suppresses the increase in surplus power. In particular, the control device 50 according to this embodiment can operate the combustion boiler 1 at the minimum load when there is a power surplus. This allows the control device 50 to control the flow rate of combustion exhaust gas 4 to the minimum, and the load on the carbon dioxide recovery device 34 can be minimized. In addition, the amount of power generated by the generator 40 is minimized, further suppressing the increase in surplus power. [Explanation of Symbols]

[0119] 1: Combustion boiler, 2: Fuel, 3: Combustion air, 4: Combustion exhaust gas, 5: Absorption tower, 6: Regeneration tower, 7: Carbon dioxide in absorbent liquid, 8: Carbon dioxide, 9: Condenser pump, 10: Steam turbine, 11: Extracted steam, 12: Branch water, 13: Valve, 14: Valve, 15: First heat source fluid, 16: Second heat source fluid, 17: Valve, 18: Valve, 19: Valve, 20: Conveyor, 21: Third heat source fluid, 22: Thermal storage tank, 23: Water, 24: Steam, 25: Valve, 26: Valve, 27: Valve, 28: Valve, 29: Valve, 30: Valve, 31: Valve, 32: Valve, 33: Heat transfer medium, 34: Carbon dioxide recovery device, 35: Condenser, 40: Generator, 50: Control device, 100~100e: Thermal power generation system.

Claims

1. A combustion boiler that heats the transported water by burning it with a fuel containing carbon atoms to generate steam, A steam turbine that is driven by the steam discharged from the aforementioned combustion boiler, A generator driven using the driving force of the aforementioned steam turbine, A condenser that cools the exhaust from the steam turbine and condenses it into water, A pump for circulating the aforementioned water, A heat storage tank that absorbs and stores the heat contained in the heat source fluid by the flow of the heat source fluid, which is all or part of the steam flowing out of the combustion boiler, or steam or water flowing inside the combustion boiler, A carbon dioxide recovery device that uses the heat released from the heat storage tank as a heat source and recovers carbon dioxide from the combustion exhaust gas discharged by the combustion boiler, Equipped with, A thermal power generation system that, when the steam turbine is being driven to rotate using the steam, stops the flow of the heat source fluid to the heat storage tank and supplies heat from the heat storage tank to the carbon dioxide recovery device.

2. The thermal power generation system according to claim 1, wherein when steam from the combustion boiler is not supplied to the steam turbine, the heat source fluid is circulated to the heat storage tank.

3. When there is a power surplus, the heat storage operation is performed, the heat source fluid is circulated to the heat storage tank, and heat is absorbed from the heat source fluid and stored. The thermal power generation system according to claim 1, wherein when there is no power surplus, a heat dissipation operation is performed, and the heat dissipated from the heat storage tank is supplied to the carbon dioxide recovery device and used as a heat source for the carbon dioxide recovery device.

4. A thermal power generation system according to any one of claims 1 to 3, wherein, when performing thermal storage operation, heat from the heat source fluid is stored in the thermal storage tank, and heat from the heat source fluid is supplied to the carbon dioxide recovery device for use as a heat source for the carbon dioxide recovery device.

5. A thermal power generation system according to any one of claims 1 to 3, wherein when there is a power surplus, the combustion boiler is operated at a lower load than when there is no power surplus.

6. The flow path for the steam discharged from the combustion boiler can be branched into a flow path that flows into the steam turbine and a flow path that does not flow into the steam turbine but flows into the heat storage tank or the carbon dioxide recovery device. A thermal power generation system according to any one of claims 1 to 3, wherein when there is a power surplus, the system operates in a way that does not circulate the steam through the steam turbine.

7. A thermal power generation system according to any one of claims 1 to 3, wherein when performing thermal storage operation, the heat source fluid is circulated to the thermal storage tank, and the heat source fluid that has flowed out of the thermal storage tank is flowed into the combustion boiler.

8. A thermal power generation system according to any one of claims 1 to 3, wherein when performing heat dissipation operation, heat is transferred from the heat storage tank to the carbon dioxide recovery device by circulating a heat transfer medium between the heat storage tank and the carbon dioxide recovery device.

9. The thermal power generation system according to claim 8, wherein the heat transfer medium is the same substance as the substance flowing through the combustion boiler, and the flow path of the heat transfer medium during heat storage operation and the flow path during heat release operation partially overlap.

10. A thermal power generation system according to any one of claims 1 to 3, wherein when the heat of the heat source fluid is transferred to the carbon dioxide recovery device for use, the heat source fluid is circulated to the carbon dioxide recovery device, and the heat source fluid discharged from the carbon dioxide recovery device is flowed into the combustion boiler.

11. A thermal power generation system according to any one of claims 1 to 3, wherein when heat from the heat source fluid is stored in the heat storage tank and heat from the heat source fluid is transferred to the carbon dioxide recovery device for use as a heat source for the carbon dioxide recovery device, the heat source fluid is branched and flows into the carbon dioxide recovery device and the heat storage tank, respectively, and the heat source fluid that flows out from the carbon dioxide recovery device and the heat storage tank, respectively, flows into the combustion boiler.

12. The thermal power generation system according to claim 11, wherein when heat from the heat source fluid is stored in the heat storage tank and heat from the heat source fluid is transferred to the carbon dioxide recovery device for use as a heat source for the carbon dioxide recovery device, the heat source fluid flowing into the carbon dioxide recovery device is a fluid extracted from steam or water circulating inside the combustion boiler, and the heat source fluid flowing into the heat storage tank is steam discharged from the combustion boiler.

13. A thermal power generation system according to any one of claims 1 to 3, wherein when heat from the heat source fluid is stored in the heat storage tank, and heat from the heat source fluid is transferred to the carbon dioxide recovery device for use as a heat source for the carbon dioxide recovery device, the heat source fluid is introduced into the carbon dioxide recovery device, the heat source fluid discharged from the carbon dioxide recovery device is introduced into the heat storage tank, and the heat source fluid discharged from the heat storage tank is introduced into the combustion boiler.

14. A thermal power generation system according to any one of claims 1 to 3, wherein when heat from the heat source fluid is stored in the heat storage tank and the heat from the heat source fluid is transferred to the carbon dioxide recovery device for use as a heat source for the carbon dioxide recovery device, the heat source fluid is introduced into the heat storage tank, the heat source fluid that has flowed out of the heat storage tank is introduced into the carbon dioxide recovery device, and the heat source fluid that has flowed out of the carbon dioxide recovery device is introduced into the combustion boiler.

15. A thermal power generation system according to any one of claims 1 to 3, wherein, during thermal storage operation, a fluid obtained by combining the heat source fluid and branched water branched from the water flowing into the combustion boiler is fed into the carbon dioxide recovery device or the thermal storage tank.

16. A thermal power generation system according to any one of claims 1 to 3, wherein during heat dissipation operation, the fluid toward the heat storage tank is branched, one branch flows through the heat storage tank and the other bypasses the heat storage tank, then the two branches are merged and flow into the carbon dioxide recovery device.

17. The carbon dioxide recovery device is An absorption tower that uses a water-containing absorbent liquid to absorb carbon dioxide, A regeneration tower that releases carbon dioxide from the absorbent liquid supplied from the absorption tower, The regenerating tower has a reboiler for heating the absorbent liquid, A thermal power generation system according to any one of claims 1 to 3, wherein the heat released from the heat storage tank is used to heat the absorbent liquid in the reboiler.

18. A control device for a thermal power generation system comprising: a combustion boiler that heats transported water by burning it with a fuel containing carbon atoms to generate steam; a steam turbine that is rotationally driven using the steam discharged from the combustion boiler; a generator that is driven using the driving force of the steam turbine; a condenser that cools the exhaust from the steam turbine and condenses it into water; a pump that circulates the water; a heat storage tank that absorbs and stores heat by circulating a heat source fluid which is all or part of the steam discharged from the combustion boiler, or steam or water circulating inside the combustion boiler; and a carbon dioxide recovery device that uses the heat released from the heat storage tank as a heat source and recovers carbon dioxide from the combustion exhaust gas discharged from the combustion boiler, The control device is a control device for a thermal power generation system that, when the steam turbine is being driven to rotate using the steam, stops the flow of the heat source fluid to the heat storage tank and supplies heat from the heat storage tank to the carbon dioxide recovery device.

Images