JP2023070602A - power generation system - Google Patents

Abstract

To provide a power generation system capable of flexibly activating a hot module including an SOFC by previously collecting and storing waste-heat generated at the hot module.SOLUTION: A power generation system 1 comprises a hot module 10 including an SOFC (Solid Oxide Fuel Cell) and a heat storage unit 30 for storing heat contained in oxidant gas from the hot module 10. The hot module 10 including the SOFC and the heat storage unit 30 are connected, which makes it possible to store heat of the oxidant gas in the heat storage unit 30 by making oxidant gas (e.g., air) from the hot module 10 flow to the heat storage unit 30.SELECTED DRAWING: Figure 1

Description

The present invention relates to a power generation system using hot modules including SOFCs.

A hot module having a SOFC (Solid Oxide Fuel Cell) operates at about 700 to 900° C. to generate electricity. Since hot modules generate heat during power generation, this heat is used for hot water supply, various heating applications, and heat sources for heat engines such as steam turbines and gas turbines.

Non-Patent Document 1 discloses that it is possible to extract steam from a steam turbine, store it at a high temperature, and return the stored heat energy to the power generation process in order to meet the demands of system frequency control and load balance. .

In Non-Patent Document 2, regarding combined cycle gas turbine power generation that combines cascade-type latent heat storage, it is possible to store a large amount of thermal energy by cascade-type latent heat storage at start-up, and in load-following operation, extracted exhaust gas is heat. It can be used for energy storage, the stored heat can be released to produce high temperature and high pressure steam, which can be supplied to the steam turbine, and the stored heat can keep the heat recovery boiler warm and restart the plant. It is disclosed to shorten the time.

[3], a direct steam generation photovoltaic power plant with a solar field operated in recirculation mode with a phase separator between preheating and evaporating and superheating sections, a heat storage system and a turbine. A plant is disclosed.

Non-Patent Document 4 discloses three storage systems comprising a concrete preheater, a PCM evaporator, and a concrete superheater unit. It is disclosed that the part is evaporated, the steam is separated from the water in the steam drum, the steam is superheated in the concrete unit and the remaining water is recycled to PCM storage.

Li D, Wang J., Study of supercritical power plant integration with high temperature thermal energy storage for flexible operation. J. Energy Storage 20 (2018) pp.140-152. Li D, Hu Y, Li D and Wang J, Combined-cycle gas turbine power plant integration with cascaded latent heat thermal storage for fast dynamic responses. Energy Conversion and management 183 (2019) pp.1-13. Birnbaum et al., A Direct Steam Generation Solar Power Plant With Integrated Thermal Storage Journal of Solar Energy Engineering Vol. 132(3), (2010) 031014. Liang D et al., Thermal energy storage for direct steam generation, Solar Energy, Vol.85(4) (2011) pp.627-633.

However, hot modules including SOFCs have the problem that it takes time to start and stop, making it difficult to flexibly generate power according to demand.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a power generation system capable of recovering and accumulating exhaust heat generated in a hot module including an SOFC and flexibly starting the hot module.

One concept of the present invention is a power generation system having a hot module containing an SOFC and a thermal storage unit that stores heat contained in the oxidant gas from the hot module. Since the hot module including the SOFC and the heat storage unit are connected, the heat of the oxidant gas can be stored in the heat storage unit by flowing the oxidant gas (for example, air) from the hot module to the heat storage unit. Therefore, the heat stored in the heat storage unit is given to the medium (water) flowing in the medium path to generate steam, and the steam is made to flow through the turbine to rotate the turbine, and the generator connected to the turbine generates electricity. be able to. When the hot module is not generating electricity, the heat of the oxidant gas can be stored in the heat storage unit by flowing the oxidant gas from the hot module to the heat storage unit, that is, the exhaust heat of the hot module can be stored. can. Therefore, the temperature of the hot module can be maintained in the vicinity of the operating temperature by the heat of the heat storage unit by flowing the oxidant gas to be flowed to the hot module through the heat storage unit in advance to the cathode channel of the hot module. In this manner, the heat storage unit recovers and accumulates the exhaust heat generated in the hot module including the SOFC, and the hot module can be activated flexibly.

According to the present invention, it is possible to provide a power generation system capable of recovering and accumulating exhaust heat generated in a hot module including an SOFC and flexibly starting the hot module.

FIG. 1 is a diagram showing an outline of a power generation system according to a first embodiment of the present invention, schematically showing internal connections of four-way valves in a power generation or heat storage mode, and a medium containing an oxidant gas. It is also a diagram showing the flow. FIG. 2 is a diagram showing the flow of a medium containing an oxidant gas in a warm-up mode in which no power is being generated in a hot module in the power generation system shown in FIG. FIG. 3 is a diagram showing an outline of a power generation system according to a second embodiment of the present invention, schematically showing internal connections of four-way valves in a power generation or heat storage mode, and a medium containing an oxidant gas. It is also a diagram showing the flow. 4 is a diagram showing the flow of a medium containing oxidant gas in a warm-up mode in which no power is being generated in the hot module in the power generation system shown in FIG. 3. FIG. FIG. 5 is a diagram schematically showing a state in which an existing boiler and a steam turbine are installed side by side in a thermal power plant. FIG. 6 is a diagram schematically showing a power generation system according to a third embodiment of the invention. FIG. 7 is a diagram schematically showing hot modules and flow paths connected thereto in a power generation system according to a fourth embodiment of the present invention. FIG. 8 is a diagram schematically showing main parts of a power generation system according to a fifth embodiment of the present invention. FIG. 9 is a diagram schematically showing main parts of a power generation system according to a sixth embodiment of the present invention. 10A to 10D are cross-sectional views of the heat storage unit.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It is possible to appropriately combine the constituent elements or remove some of them as required, and these are also included in the embodiments of the present invention.

[First embodiment]
FIG. 1 is a diagram showing an outline of a power generation system according to a first embodiment of the present invention, schematically showing internal connections of four-way valves in a power generation or heat storage mode, and a medium containing an oxidant gas. It is also a diagram showing the flow. A power generation system 1 according to the first embodiment of the present invention includes a hot module 10 including an SOFC and a heat storage unit 30 .

The hot module 10 generates electricity by reacting hydrogen, hydrocarbons, alcohol, ammonia, etc. contained in the fuel gas with oxygen contained in the oxidant gas in the cell stack. In the hot module 10, an electrolyte body (not shown) is arranged between an anode channel (not shown) through which the fuel gas flows and a cathode channel (not shown) through which the oxidant gas flows, Solid oxide ceramics are used as electrolyte bodies in all of the embodiments of the present invention. The hot module 10 may include a reformer (not shown) for reforming fuel, or may incorporate a combustor 16, which will be described later.

A blower 11 , a preheater 12 and a mixer 13 are provided in this order on the upstream side of the anode channel of the hot module 10 . A first fuel supply line 51 is provided between the blower 11 and the preheater 12, a second fuel supply line 52 is provided between the preheater 12 and the mixer 13, and a third fuel supply line 53 is provided. is provided between the mixer 13 and the anode flow path of the hot module 10 .

A valve 14 and a blower 15 are provided downstream of the anode flow path of the hot module 10 . A first flue gas flow path 54 is provided between the anode flow path of the hot module 10 and the valve 14, a second flue gas flow path 55 is provided between the valve 14 and the blower 15, and a third A flue gas passage 56 is provided between the blower 15 and the mixer 13, a fourth flue gas passage 57 is provided between the valve 14 and the preheater 12, and a fifth flue gas passage 58 is provided between the valve 14 and the preheater 12. It is provided between the preheater 12 and the combustor 16 .

The upstream and downstream of the anode channel of the hot module 10 are configured as described above, and the fuel introduced by the blower 11 in the preheater 12 is preheated using the heat of the fuel exhaust gas from the fourth fuel exhaust gas channel 57. The fuel from the second fuel supply passage 52 and the unreacted fuel exhaust gas from the third fuel exhaust gas passage 56 are mixed in the mixer 13 to produce a third fuel supply. It can flow into the path 53 . The exhaust gas of the unreacted fuel that has flowed out from the anode flow path of the hot module 10 flows partially to the blower 15 and partially to the preheater 12 through the valve 14 . The unreacted fuel exhaust gas flowing to the preheater 12 flows to the combustor 16 via the fifth fuel exhaust gas flow path 58, and is mixed with the oxidant gas (here, the oxidant gas to be exhausted) to be described later and combusted. do.

A blower 21, a preheater 22, and a preheater 23 are provided upstream of the cathode flow path when the hot module 10 is generating power. A first oxidant gas channel 61 is provided between the blower 21 and the preheater 22, a second oxidant gas channel 62 is provided between the preheater 22 and the preheater 23, and a third An oxidant gas channel 63 is provided between the preheater 23 and the four-way valve 24, and a fourth oxidant gas channel 64 is provided between the four-way valve 24 and the cathode channel of the hot module 10. .

A valve 25 is provided between the hot module 10 and the heat storage unit 30 on the downstream side of the cathode flow path when the hot module 10 is generating power. a fifth oxidant gas flow path 65 is provided between the cathode flow path of the hot module 10 and the valve 25, a sixth oxidant gas flow path 66 is provided between the valve 25 and the combustor 16; A seventh oxidant gas flow path 67 is provided between the valve 25 and the heat storage unit 30 .

An eighth oxidizing gas flow path 68 is internally connected to the seventh oxidizing gas flow path 67 in the heat storage unit 30 , and the eighth oxidizing gas flow path 68 connects the heat storage unit 30 and the four-way valve 24 . A ninth oxidizing gas flow path 69 is provided between the four-way valve 24 and the preheater 22 , and a tenth oxidizing gas flow path 70 is provided between the preheater 22 and the oxidizing gas stack 26 is provided between

A flue gas channel 71 is provided between the combustor 16 and the preheater 23 , and a flue gas channel 72 is provided between the preheater 23 and the flue gas stack 27 .

While the hot module 10 is generating power or heat is being stored in the heat storage unit 30, the four-way valve 24 is schematically shown in FIG. As shown, of the four input/output ports, the third oxidant gas channel 63 and the fourth oxidant gas channel 64 are connected, and the eighth oxidant gas channel 68 is connected. and the ninth oxygen-containing gas flow path 69 are connected.

In the state where the four-way valve 24 is shown in FIG. 1, the oxidant gas such as air introduced by the blower 21 in the preheater 22 is preheated by the heat of the oxidant gas in the ninth oxidant gas flow path 69. The oxidant gas such as air preheated by the preheater 22 in the preheater 23 is preheated by the heat of the flue gas in the flue gas flow path 71, flows to the four-way valve 24, and flows into the cathode flow path. flow. Oxidant gas containing unreacted oxidant gas (exhausted oxidant gas) flowed out from the cathode flow path flows into valve 25, and part of it flows into combustor 16 to burn the unreacted fuel gas, resulting in flue gas. flows into the flue gas passage 71 and becomes the heat source of the preheater 23 , and is emitted from the flue gas stack 27 via the flue gas passage 72 . On the other hand, the exhausted oxidant gas containing the unreacted oxidant gas flowing out from the cathode channel flows to the valve 25, and part of it flows to the heat storage unit 30 via the seventh oxidant gas channel 67. , the heat of the exhausted oxidant gas is stored in the heat storage unit 30 . The exhausted oxidant gas flowing out of the heat storage unit 30 flows into the eighth oxidant gas flow path 68, flows through the four-way valve 24 to the preheater 22, becomes the heat source of the preheater 22, and then flows into the tenth oxidant gas. It is discharged from the oxidizing gas stack 26 via the gas flow path 70 .

FIG. 2 is a diagram showing the flow of the medium containing the oxidant gas in the warm-up mode in which no power is being generated in the hot module 10 in the power generation system 1 shown in FIG. When the hot module 10 is in the warm-up mode, the four-way valve 24 is connected to the third oxidizing gas channel 63 and the eighth oxidizing gas channel 68 among the four input/output ports, and the fourth oxidizing gas channel 68 is connected. and the ninth oxidant gas channel 69 are connected. In the warm-up mode, fuel exhaust gas flows through the fifth fuel exhaust gas flow path 58, oxidizing gas flows through the sixth oxidizing gas flow path 66, and flue gas flows through the flue gas flow path 71 and the flue gas flow path 72. It's basically not flowing.

The oxidant gas such as air introduced by the blower 21 in the preheater 22 is preheated by the heat of the oxidant gas in the ninth oxidant gas flow path 69 and flows into the four-way valve 24 to form the eighth oxidant gas flow. It flows to the thermal storage unit 30 via passage 68 . The temperature of the oxidant gas such as air that has flowed into the heat storage unit 30 is increased, and the oxidant gas flows to the valve 25 via the seventh oxidant gas flow path 67 . It flows from the valve 25 to the cathode flow path of the hot module 10 via the fifth oxidizing gas flow path 65 . The oxidant gas flowing out from the cathode channel flows into the preheater 22 via the fourth oxidant gas channel 64, the four-way valve 24, and the ninth oxidant gas channel 69, and serves as a heat source for the preheater 22. After that, it is discharged from the oxidizing gas stack 26 via the tenth oxidizing gas flow path 70 .

In the first embodiment of the present invention, the four-way valve 24 is provided between one inlet/outlet of the cathode channel of the hot module 10 and one inlet/outlet of the heat storage unit 30, and the gas (oxidant gas) in the heat storage unit 30 is ) flow in the opposite direction during SOFC operation and during warm-up.

Specifically, as shown in FIG. 1, the four-way valve 24 is connected to one inlet/outlet of the cathode channel of the hot module 10 (specifically, the fourth oxidant gas channel 64). , a channel connected to the preheater 23 (specifically, the third oxidizing gas channel 63) and a channel connected to the heat storage unit 30 (specifically, the eighth oxidizing gas channel 68). ) and a channel (specifically, the ninth oxidizing gas channel 69) connected to the preheater 22. As shown in FIG.

Here, the preheater 22 uses the heat of the oxidizing gas flowing from the heat storage unit 30 to raise the temperature of the oxidizing gas flowing from the blower 21 to the hot module 10 . The preheater 23 uses the heat of the flue gas generated by burning the unreacted fuel gas in the combustor 16 to further raise the temperature of the oxidant gas flowing from the preheater 22 to the hot module 10 .

When the hot module 10 is in the power generation or heat storage mode, as shown in FIG. The oxygen-containing gas channel 68 and the ninth oxygen-containing gas channel 69 are connected. In the warm-up mode of the hot module 10, as shown in FIG. The gas channel 64 and the ninth oxidant gas channel 69 are connected.

As described above, the power generation system 1 according to the first embodiment of the present invention flows the fuel gas and the oxidant gas through the anode channel and the cathode channel of the hot module 10, respectively, and generates power. In the mode or the mode in which heat is stored in the heat storage unit 30, the heat generated in the hot module 10 is stored in the heat storage unit 30, and in the mode in which the hot module 10 is warmed up, the low-temperature oxidant containing air is used. The heat of the heat storage unit 30 can be transferred to the hot module 10 by raising the temperature of the gas in the heat storage unit 30 and then flowing it through the cathode channel of the hot module 10 . Accordingly, it is possible to provide a power generation system capable of recovering and accumulating exhaust heat generated in a hot module including an SOFC and flexibly activating the hot module.

In the power generation system 1 according to the first embodiment of the present invention, in the mode in which the hot module 10 is generating power and in the mode in which the heat storage unit 30 is storing heat, as shown in FIG. and the heat storage unit 30 in the clockwise direction on the paper surface, but when the hot module 10 is in the warm-up mode, as shown in FIG. It flows counterclockwise upwards. Thus, in the power generation system 1, the flow of the oxidant gas between the hot module 10 and the heat storage unit 30 is reversed between the warm-up mode and the heat storage mode (including the power generation mode).

[Second embodiment]
FIG. 3 is a schematic diagram of a power generation system according to a second embodiment of the present invention, schematically showing the internal connection of two four-way valves in the power generation or heat storage mode, and containing oxidant gas. It is also a diagram showing the flow of the medium. A power generation system 2 according to a second embodiment of the present invention includes a hot module 10 including an SOFC and a heat storage unit 30 . Since the structure and action inside the hot module 10 are the same as those of the first embodiment, description thereof will be omitted. The configuration and piping on the upstream and downstream sides of the anode channel of the hot module 10 are the same as in the first embodiment, so the same reference numerals are given and the description thereof is omitted.

A blower 21, a preheater 22, and a preheater 23 are provided upstream of the cathode flow path when the hot module 10 is generating power. A first oxidant gas channel 81 is provided between the blower 21 and the preheater 22, a second oxidant gas channel 82 is provided between the preheater 22 and the preheater 23, and a third An oxidizing gas flow path 83 is provided between the preheater 23 and the first four-way valve 24, and a fourth oxidizing gas flow path 84 is provided between the first four-way valve 24 and the second four-way valve 28. , and a fifth oxidizing gas flow path 85 is provided between the second four-way valve 28 and the cathode flow path of the hot module 10 .

A valve 25 is provided between the second four-way valve 28 and the downstream side of the cathode channel when the hot module 10 is generating power. a sixth oxidant gas flow path 86 is provided between the cathode flow path of the hot module 10 and the valve 25, a seventh oxidant gas flow path 87 is provided between the valve 25 and the combustor 16; An eighth oxidant gas flow path 88 is provided between the valve 25 and the second four-way valve 28 .

A ninth oxidant gas flow path 89 is provided between the second four-way valve 28 and the heat storage unit 30 , and a tenth oxidant gas flow path 90 is provided between the heat storage unit 30 and the ninth oxidant gas flow path. A tenth oxidant gas channel 90 is provided to be connected to the first four-way valve 24, and an eleventh oxidant gas channel 91 is connected to the first four-way valve 24. Provided between the valve 24 and the preheater 22 , a twelfth oxidizing gas flow path 92 is provided between the preheater 22 and the oxidizing gas stack 26 .

A flue gas channel 93 is provided between the combustor 16 and the preheater 23 , and a flue gas channel 94 is provided between the preheater 23 and the flue gas stack 27 .

While the hot module 10 is generating power or heat is being stored in the heat storage unit 30, the upstream and downstream of the cathode flow path of the hot module 10 are configured as described above. As schematically shown, of the four input/output ports, the third oxidizing gas channel 83 and the fourth oxidizing gas channel 84 are connected, and the tenth oxidizing gas channel The channel 90 and the eleventh oxygen-containing gas channel 91 are configured to be connected. As schematically shown in FIG. 3, the second four-way valve 28 has four input/output ports, of which the fourth oxidant gas channel 84 and the fifth oxidant gas channel 85 are are connected, and the eighth oxidizing gas flow path 88 and the ninth oxidizing gas flow path 89 are configured to be connected.

In the state where the first four-way valve 24 and the second four-way valve 28 are shown in FIG. 3, the oxidant gas such as air introduced by the blower 21 in the preheater 22 flows through the eleventh oxidant gas flow path. The oxidant gas such as air preheated by the heat of the oxidant gas in 91 flows into the preheater 23, and the oxidant gas such as air preheated by the preheater 22 is preheated by the heat of the flue gas in the flue gas passage 93. It flows through the first four-way valve 24, through the fourth oxidizing gas flow path 84, into the second four-way valve 28, through the fifth oxidizing gas flow path 85, into the cathode flow path. Exhausted oxidant gas containing unreacted oxidant gas that has flowed out of the cathode flow path flows through the sixth oxidant gas flow path 86 to the valve 25 and partly flows to the combustor 16 to remove unreacted fuel gas. After burning, the flue gas flows into the flue gas passage 93 and becomes the heat source of the preheater 23 , and is emitted from the flue gas stack 27 via the flue gas passage 94 . On the other hand, the exhausted oxidizing gas containing unreacted oxidizing gas flowing out from the cathode channel flows into the valve 25, and a part of it flows through the eighth oxidizing gas channel 88 to the second four-way valve 28. The heat of the exhausted oxidizing gas is accumulated in the heat accumulating unit 30 by flowing into the ninth oxidizing gas flow path 89 through the heat accumulating unit 30 . The exhausted oxidizing gas flowing out of the heat storage unit 30 passes through the tenth oxidizing gas flow path 90, the first four-way valve 24, and the eleventh oxidizing gas flow path 91 to the preheater 22. to become the heat source of the preheater 22 , and then discharged from the oxidizing gas stack 26 via the twelfth oxidizing gas flow path 92 .

FIG. 4 is a diagram showing the flow of the medium containing the oxidant gas in the warm-up mode in which no power is being generated in the hot module 10 in the power generation system 2 shown in FIG. When the hot module 10 is in the warm-up mode, the first four-way valve 24, as schematically shown in FIG. , and the fourth oxidizing gas channel 84 and the eleventh oxidizing gas channel 91 are connected. As schematically shown in FIG. 4, the second four-way valve 28 has four input/output ports, of which the fourth oxidant gas channel 84 and the eighth oxidant gas channel 88 are , and the fifth oxidizing gas channel 85 and the ninth oxidizing gas channel 89 are connected.

The oxidant gas such as air introduced by the blower 21 in the preheater 22 is preheated by the heat of the oxidant gas in the eleventh oxidant gas flow path 91, and the preheater 23 and the third oxidant gas flow path are preheated. 83 to the first four-way valve 24 , and the tenth oxidizing gas flow path 90 to the heat storage unit 30 . The oxidizing gas such as air that has flowed into the heat storage unit 30 is heated in the heat storage unit 30, flows through the ninth oxidizing gas flow path 89 into the second four-way valve 28, and flows into the fifth oxidizing gas flow. It flows to the cathode flow path of hot module 10 via passage 85 . The oxidizing gas flowing out from the cathode channel flows through the sixth oxidizing gas channel 86 to the valve 25 . From the valve 25 through the eighth oxidizing gas flow path 88, through the second four-way valve 28, the fourth oxidizing gas flow path 84, the first four-way valve 24, and the eleventh oxidizing gas flow path 91 It becomes a heat source for the preheater 22 and is then discharged from the oxidizing gas stack 26 via the twelfth oxidizing gas flow path 92 .

In the second embodiment of the present invention, a first four-way valve 24 and a second four-way valve 28 are provided between the inlet and outlet of the cathode channel of the hot module 10 and the inlet and outlet of the heat storage unit 30. ing. By switching both the first four-way valve 24 and the second four-way valve 28, the direction of gas flow in the heat storage unit 30 is reversed between during SOFC operation and during warm-up, and the direction of gas flow in the hot module 10 is reversed. flows in the same direction during SOFC operation and during warm-up.

Specifically, as shown in FIG. 3, the first four-way valve 24 is connected to the preheater 23 and is a flow path through which the oxidizing gas is introduced (specifically, the third oxidizing gas flow path 83). , the channel connected to the second four-way valve 28 (specifically, the fourth oxidant gas channel 84), and the oxidant gas connected to the preheater 22 and flowing from the cathode channel of the hot module 10. is used as a heat source to preheat the oxidizing gas flowing through the cathode flow path of the hot module 10 (specifically, the eleventh oxidizing gas flow path 91), and a flow path connected to the outlet of the heat storage unit 30 (specifically, Specifically, it is provided so as to be connected to the tenth oxidizing gas flow path 90).

A second four-way valve 28 is connected to the flow path (specifically, the fourth oxidant gas flow path 84) connected to the first four-way valve 24 and to the inlet of the cathode flow path of the hot module 10. A channel (specifically, the fifth oxidant gas channel 85) and a channel (specifically, the eighth oxidant gas channel 85) connected to the valve 25 on the outlet side of the cathode channel of the hot module 10. channel 88) and a channel connected to the inlet of the heat storage unit 30 (specifically, the ninth oxidant gas channel 89).

Here, the preheater 22 uses the heat of the oxidizing gas to raise the temperature of the oxidizing gas flowing from the blower 21 to the hot module 10 . The preheater 23 uses the heat of the flue gas generated by burning the unreacted fuel gas in the combustor 16 to further raise the temperature of the oxidant gas flowing from the preheater 22 to the hot module 10 .

When the hot module 10 is in the power generation or heat storage mode, the first four-way valve 24 connects the third oxidant gas channel 83 and the fourth oxidant gas channel 84, The tenth oxygen-containing gas channel 90 and the eleventh oxygen-containing gas channel 91 are connected. The fourth oxidizing gas flow path 84 and the fifth oxidizing gas flow path 85 are connected by the second four-way valve 28, and the eighth oxidizing gas flow path 88 and the ninth oxidizing gas flow are connected. 89 are connected.

When the hot module 10 is in the warm-up mode, as shown in FIG. 4 oxidant gas channel 84 and the eleventh oxidant gas channel 91 are connected. The fourth oxidizing gas flow path 84 and the eighth oxidizing gas flow path 88 are connected by the second four-way valve 28, and the ninth oxidizing gas flow path 89 and the fifth oxidizing gas flow are connected. 85 are connected.

As described above, the power generation system 2 according to the second embodiment of the present invention flows the fuel gas and the oxidant gas through the anode channel and the cathode channel of the hot module 10, respectively, and generates power. In the mode or the mode in which heat is stored in the heat storage unit 30, the heat generated in the hot module 10 is stored in the heat storage unit 30, and in the mode in which the hot module 10 is warmed up, the low-temperature oxidant containing air is used. The heat of the heat storage unit 30 can be transferred to the hot module 10 by raising the temperature of the gas in the heat storage unit 30 and then flowing it through the cathode channel of the hot module 10 . Accordingly, it is possible to provide a power generation system capable of recovering and accumulating exhaust heat generated in a hot module including an SOFC and flexibly activating the hot module.

In the power generation system 2 according to the second embodiment of the present invention, as shown in FIG. and the heat storage unit 30 in the clockwise direction on the paper surface. Even when the hot module 10 is in the warm-up mode, the oxidant gas flows clockwise between the hot module 10 and the heat storage unit 30 as shown in FIG. As described above, unlike the first embodiment, the power generation system 2 is provided with the first four-way valve 24 and the second four-way valve 28 to prevent oxidation between the hot module 10 and the heat storage unit 30. The agent gas flow is the same in warm-up mode and heat storage mode (including power generation mode).

The power generation system 1 according to the first embodiment and the power generation system 2 according to the second embodiment are installed together in a thermal power plant having an existing boiler and a steam turbine. FIG. 5 is a diagram schematically showing a state in which an existing boiler and a steam turbine are installed side by side in a thermal power plant.

The thermal power plant 3 has a boiler 110 and a steam turbine 120 . The boiler 110 is composed of an economizer 111 , an evaporator 112 , a superheater 113 and a reheater 114 . The steam turbine 120 includes a first steam turbine 121 , a second steam turbine 122 and a third steam turbine 123 coaxially arranged, and their shafts are connected to the generator 130 . The first steam turbine 121 is a high pressure steam turbine, the second steam turbine 122 is an intermediate pressure steam turbine and the third steam turbine 123 is a low pressure steam turbine.

In the thermal power plant 3 , the medium (water) flowing in the boiler 110 is heated by the economizer 111 , passed through the evaporator 112 to be evaporated, and superheated by the superheater 113 . The superheated medium (steam) is introduced to the first steam turbine 121 , part of which flows to the reheater 114 to be reheated and flows to the second steam turbine 122 , and the remainder to the preheater 131 .

The medium (steam) from the reheater 114 is introduced into the second steam turbine 122 and part of it is extracted and flows to the preheater 132, while part flows to the third steam turbine 123 and the rest is desorbed. It flows to deaerator 133 .

A medium (steam) from the second steam turbine 122 is introduced into the third steam turbine 123, a portion of which is extracted stepwise and flows to preheaters 134, 135, and 136, and the remainder Flowing to the condenser 137 and liquefied, the medium (water) is fed by the pump 138 to the preheater 136, fed from the preheater 136 to the preheater 135, further fed from the preheater 135 to the preheater 134, and degassed. In vessel 133 , it is degassed together with medium from second steam turbine 122 and introduced to pump 139 . The degassed medium is pumped up by the pump 139 and flows through the preheater 132 , the preheater 131 in order, and then the economizer 111 .

In such a thermal power plant 3, when heat is stored in the water medium path of the heat storage unit 30 shown in FIGS. By flowing the medium (steam) from the heat storage unit 30 to the first steam turbine 121, the first steam turbine 121, the second steam turbine 122, and the third steam turbine 123 are rotated, A generator 130 generates power.

Thus, the power generation systems 1 and 2 according to the first embodiment and the second embodiment of the present invention are installed side by side with the existing thermal power plant 3, so that the heat storage unit 30 is topped as a heat source, or simply Power generation efficiency can be increased by adding a hot module including an SOFC or repowering a steam turbine by adding a gas turbine. In such a case, an SOFC with a relatively small capacity (for example, about tens of thousands of kW) can be adopted.

Furthermore, the heat source of the heat storage unit 30 can heat the medium flowing from the first steam turbine 121 to the second steam turbine 122 . As shown in FIG. 5 , reheater flow paths 115 and 116 may be provided between the heat storage unit 30 and the reheater 114 . As shown in FIG. 1, the heat generated in the hot module 10 is stored as the oxidant gas flows from the seventh oxidant gas channel 67 to the eighth oxidant gas channel 68 via the heat storage unit 30 . Store in unit 30. As shown in FIG. 3, the oxidizing gas flows from the ninth oxidizing gas channel 89 to the tenth oxidizing gas channel 90 via the heat storage unit 30, and the heat generated in the hot module 10 is accumulated. Store in unit 30. By flowing a medium between the heat storage unit 30 and the reheater 114 using the reheater flow paths 115 and 116, the heat of the heat storage unit 30 is transferred from the first steam turbine 121 to the second steam turbine 122 in the reheater 114. used for reheating the medium flowing through the

[Third Embodiment]
The power generation system according to the third embodiment of the present invention is the power generation system 2 according to the second embodiment in which the heat storage units are three-stage heat storage tanks. In this case, it may be installed alongside an existing thermal power plant, but a steam turbine and a power generator are newly incorporated into the power generation system 4 . FIG. 6 is a diagram schematically showing a power generation system according to a third embodiment of the invention. It should be noted that the power generation system 1 according to the first embodiment may also be similarly provided with a three-stage heat storage tank.

In the power generation system 4 according to the second embodiment, the heat storage unit 30 is a three-stage heat storage tank, that is, a first heat storage tank 31, a second heat storage tank 32, and a third heat storage tank 33. A ninth oxidant gas flow path 89 connected to the second four-way valve 28 is connected to the first branch line 34 and a tenth flow path connected to the first four-way valve 24. An oxidant gas channel 90 is connected to the second branch channel 35 .

First branch paths 36, 37, and 38 are connected from the first branch path 34 to the first heat storage tank 31, the second heat storage tank 32, and the third heat storage tank 33, respectively. A second branch channel 39 is connected to the first branch channel 36 through the inside, a second branch channel 40 is connected to the first branch channel 37 through the inside of the second heat storage tank 32, and a third heat storage tank A second branch channel 41 is connected to the first branch channel 38 through the interior of 33 , and second branch channels 39 , 40 , 41 are connected to the second branch channel 35 .

The first heat storage tank 31 is connected to the first medium passage 101 for passing the medium from the preheater 131, and the first heat storage tank 31 applies heat to the medium from the first medium passage 101. It becomes a medium (steam) whose temperature has been raised by heating, and flows from the first heat storage tank 31 to the second heat storage tank 32 through the second medium path 102 . In the second heat storage tank 32, the medium (steam) from the second medium passage 102 is superheated, flows from the second heat storage tank 32 to the first steam turbine 121 through the third medium passage 103, and The steam turbine 121 is rotated. After that, the medium from the first steam turbine 121 flows through the fourth medium path 104 to the third heat storage tank 33 , is reheated by the third heat storage tank 33 , and flows through the fifth medium path 105 to the third heat storage tank 33 . It flows from the heat storage tank 33 to the second steam turbine 122 and rotates the second steam turbine 122 . Media from the second steam turbine 122 then flows through the sixth media path 106 to the third steam turbine 123 to rotate the third steam turbine 123 .

In this power generation system 4 , part of the medium (steam) introduced into the first steam turbine 121 flows into the third heat storage tank 33 and the rest flows into the preheater 131 .

A portion of the medium (steam) introduced into the second steam turbine 122 is extracted and flows to the third steam turbine 123 and the rest flows to the deaerator 133 .

A medium (steam) from the second steam turbine 122 is introduced into the third steam turbine 123, a portion of which is extracted stepwise and flows to preheaters 134, 135, and 136, and the remainder Flowing to the condenser 137 and liquefied, the medium (water) is fed by the pump 138 to the preheater 136, fed from the preheater 136 to the preheater 135, further fed from the preheater 135 to the preheater 134, and degassed. In vessel 133 , it is degassed together with medium from second steam turbine 122 and introduced to pump 139 . The degassed medium is pumped up by pump 139 , flows to preheater 132 and preheater 131 in order, and flows to first heat storage tank 31 via first medium path 101 .

In such a power generation system 4, valves (not shown) interposed in the first to sixth medium paths 101 to 106 are provided in the water or steam medium paths of the heat storage unit 30 during heat storage and power generation. By opening to flow the medium (water) from the preheater 131 to the heat storage unit 30 and the medium (steam) from the heat storage unit 30 to the first steam turbine 121, the first steam turbine 121, the second The steam turbine 122 and the third steam turbine 123 are rotated, and the generator 130 generates electricity. When the steam turbine is not used to generate power, the valves interposed in the first to sixth medium paths 101 to 106 may be closed.

In the power generation system 1 according to the first embodiment, the power generation system according to the third embodiment of the present invention may use a three-stage heat storage tank as the heat storage unit. Although it may be installed alongside an existing thermal power plant, it may also be configured as a power generation system by newly incorporating a steam turbine and a power generator.

[Fourth embodiment]
A power generation system according to a fourth embodiment of the present invention is different from the power generation systems 1 and 2 according to the first and second embodiments in that the hot module 10 is not composed of one unit, but a plurality of small-capacity hot modules are provided. It is configured with Below, it demonstrates on the assumption of the electric power generation system 2 which concerns on 2nd Embodiment. FIG. 7 is a diagram schematically showing hot modules and flow paths connected thereto in a power generation system according to a fourth embodiment of the present invention.

A power generation system according to the fourth embodiment of the present invention is configured by installing a plurality of hot modules 10 in parallel in the power generation system 2 according to the second embodiment. Although FIG. 7 shows the case where there are three hot modules 10, the number may be two or four or more. The third fuel supply path 53 is branched and connected to the anode flow paths of the hot modules 10a, 10b and 10c, respectively. is connected to the fuel exhaust gas flow path 54 of the The fourth oxidizing gas flow path 64 is branched into three and connected to the cathode flow paths of the hot modules 10a, 10b and 10c, respectively. and connected to the fifth oxidizing gas flow path 65 .

As a result, by connecting small-scale mass-produced SOFCs and hot modules in parallel, it is possible to construct a power generation system that meets user needs.

[Fifth Embodiment]
FIG. 8 is a diagram schematically showing main parts of a power generation system according to a fifth embodiment of the present invention. The power generation system 5 according to the fifth embodiment of the present invention is the power generation system 2 according to the second embodiment, in which a water heat storage tank 95 is added to the combustion exhaust gas flow path 94 between the preheater 23 and the fuel exhaust gas stack 27 , the medium from the third steam turbine 123 is liquefied by the condenser 137, the medium is fed by the pump 138, and part of it is passed through the water heat storage tank 95 to It enables preheating by heat and flowing to the deaerator 133 .

According to the fifth embodiment, the heat generated by the hot module including the SOFC can be recovered and reused more efficiently. A water heat storage tank may also be provided in the power generation system 1 according to the first embodiment.

[Sixth Embodiment]
FIG. 9 is a diagram schematically showing main parts of a power generation system according to a sixth embodiment of the present invention. A power generation system 6 according to a sixth embodiment of the present invention is the power generation system 1 according to the first embodiment, in which a third oxidizing gas flow path 63, In the middle of the fourth oxidizing gas flow path 64, by heating using power of renewable energy (for example, surplus power, etc.), for example, heating by the resistor 97 using power generated by the solar cell panel 96 As a result, the temperature of the oxidizing gas flowing through the fourth oxidizing gas flow path 64 is raised. As a result, when the SOFC is stopped, the hot module including the SOFC can be warmed up, and heat can be stored in the heat storage unit 30 . Also in the power generation system 2 according to the second embodiment, the third oxidizing gas flow path 83 and the fifth oxidizing gas flow path 85 from the preheater 23 to the cathode flow path of the hot module 10 , by heating with renewable energy power (for example, surplus power), for example, by heating with resistance using power generated by a solar cell panel, Needless to say, the oxidant gas can be heated.

[Seventh Embodiment]
A heat storage unit will be described in detail as a seventh embodiment. The heat storage unit may be composed of molten salt, rock, or concrete. The heat storage unit is preferably made of, for example, metal PCM (Phase Change Materials). This is because most of them have a melting point in the range of 550° C. to 800° C. and are suitable for warming up the hot module 10 . Specifically, an Al--Si alloy is preferable, and an alloy containing Fe, Cu, or the like in addition to the Al--Si alloy may be used.

The heat storage unit and the heat storage tank are provided with an oxidant gas channel and a medium channel. In the power generation systems 1 and 2, in the mode in which the hot module including the SOFC generates power to rotate the steam turbine, the heat from the oxidant gas in the oxidant gas flow path is stored in the heat storage material, and the heat from the heat storage material The medium (water or steam) in the medium flow path is heated, vaporized, superheated, and reheated. In the power generation systems 1 and 2, in a mode in which the hot module including the SOFC is not generating power and heat is stored in the heat storage unit, heat from the oxidizing gas in the oxidizing gas flow path is stored in the heat storage material. In the power generation systems 1 and 2, in the mode of warming up the hot module including the SOFC, the heat from the heat storage material is transferred to the oxidizing gas in the oxidizing gas flow path.

10A to 10D are cross-sectional views of the heat storage unit. As shown in FIG. 10A, the heat storage unit 140A has a plurality of annular first flow paths 141 through which the oxidant gas flows, and a second flow path 142 through which a medium (water, steam) flows in the center. , a heat storage material 143 is filled between the first channel 141 and the second channel 142 . At this time, the first channel 141 may have a plurality of fin structures.

As shown in FIG. 10B, the heat storage unit 140B has a plurality of annular first channels 141 through which the oxidant gas flows, and a second channel 142 through which the medium (water, steam) flows in the center. , the first flow path 141 is adjacent to the outside of the second flow path 142 , and the heat storage material 143 is provided outside the first flow path 141 . At this time, the first channel 141 may have a plurality of fin structures.

As shown in FIG. 10C, the heat storage unit 140C has a second channel 142 in the center through which a medium (water, steam) flows, and a heat storage material 143 is provided outside the second channel 142. At 143 , a plurality of first flow paths 141 through which the oxidant gas flows are provided concentrically at intervals around the second flow path 142 . The cross-sectional areas of the second channel 142 and one of the first channels 141 may be substantially equal.

As shown in FIG. 10D, the heat storage unit 140D has a second channel 142 in the center through which a medium (water, steam) flows, and a heat storage material 143 is provided outside the second channel 142. At 143 , a plurality of first flow paths 141 through which the oxidant gas flows are provided concentrically at intervals around the second flow path 142 . Unlike FIG. 10C, the first flow paths 141 are provided on a plurality of (for example, two) concentric circles having different radii from the center. The first channel 141 has a smaller cross-sectional area than the second channel 142 .

As shown in FIGS. 10A to 10D, the first flow path 141 through which the oxidant gas flows is provided with heat transfer enhancement such as an enlarged heat transfer surface. This is because the oxidant gas has a lower heat transfer coefficient than the medium (water or steam).

The promotion of heat transfer as shown in FIGS. 10A to 10D is not limited to the power generation system according to the embodiment of the present invention. It is possible to increase the heat area and promote heat transfer. It may also be more generally suitable for applications in which gas-phase waste heat is taken out as steam.

1, 2, 4, 5, 6: power generation system 9: valves 10, 10a, 10b, 10c: hot module 11: blower 12: preheater 13: mixer 14: valve 15: blower 16: combustor 20: heat storage unit 21: Blowers 22, 23: Preheater 24: First four-way valve (four-way valve)
25: Valve 26: Oxidant Gas Chimney 27: Fuel Exhaust Gas Chimney 28: Second Four-Way Valves 30, 36A, 36B, 36C, 36D: Heat Storage Unit 31: First Heat Storage Tank 32: Second Heat Storage Tank 33 : Third heat storage tank 34: First branch 35: Second branch 36, 37, 38: First branch 39, 40, 41: Second branch 51: First fuel supply 52: Second fuel supply path 53: Third fuel supply path 54: First flue gas flow path 55: Second flue gas flow path 56: Third flue gas flow path 57: Fourth flue gas flow path Flow path 58: Fifth fuel exhaust gas flow path 61, 81 First oxidizing gas flow path 62, 82: Second oxidizing gas flow path 63, 83: Third oxidizing gas flow path 64, 84: Fourth oxidizing gas flow paths 65, 85: Fifth oxidizing gas flow paths 66, 86: Sixth oxidizing gas flow paths 67, 87: Seventh oxidizing gas flow paths 68, 88: Eighth Oxidant gas channels 69, 89: Ninth oxidant gas channels 70, 90: Tenth oxidant gas channels 71, 72, 93, 94: Flue gas channel 91: Eleventh oxidant gas Flow path 92: twelfth oxidant gas flow path 95: water heat storage tank 96: solar cell panel 97: resistor 101: first medium path 102: second medium path 103: third medium path 104: fourth Medium path 105: Fifth medium path 106: Sixth medium path 110: Boiler 111: Economizer (economizer)
112: Evaporator (evaporator)
113: Super heater (superheater)
114: Reheater (reheater)
115, 116: reheater flow path 120: steam turbine 121: first steam turbine 122: second steam turbine 123: third steam turbine 130: generator 131, 132, 134, 135, 136: preheater 133 : deaerator
136, 139: Pump 137: Condenser 141: First flow path 142: Second flow path 143: Heat storage material

Claims (9)

A power generation system comprising a hot module including a SOFC (Solid Oxide Fuel Cell) and a heat storage unit storing heat contained in oxidant gas from the hot module. 2. The power generation system of claim 1, further comprising a steam turbine, wherein heat stored in said thermal storage unit can vaporize a medium to generate power by said steam turbine. 2. The power generation system according to claim 1, wherein the hot module is warmed up by applying the heat stored in the heat storage unit to the oxidant gas to flow through the hot module. A four-way valve is provided between one inlet/outlet of the cathode channel of the hot module and one inlet/outlet of the heat storage unit, and the direction of gas flow in the heat storage unit is reversed during SOFC operation and during warm-up. The power generation system according to any one of claims 1 to 3, wherein A first four-way valve and a second four-way valve are provided between the cathode channel of the hot module and the heat storage unit, and both the first four-way valve and the second four-way valve are switched. Thus, the direction of gas flow in the heat storage unit is opposite during SOFC operation and during warm-up, and the direction of gas flow in the hot module is the same during SOFC operation and during warm-up. 4. The power generation system according to any one of 1 to 3. 6. The power generation system according to any one of claims 1 to 5, wherein the heat storage unit is one of metal PCM, molten salt, concrete, and rock. 7. The power generation system of any one of claims 1-6, further comprising a boiler. 8. The power generation system according to any one of claims 1 to 7, wherein a water heat storage tank is provided in the fuel exhaust gas flow path. When the hot module is in a warmed-up state, the hot module is warmed up by using renewable energy power to raise the temperature of the gas in the flow path leading from the heat storage unit to the cathode flow path of the hot module. 9. The power generation system according to any one of claims 1 to 8, wherein the heat storage unit stores heat while generating heat.

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