Energy storage device

Abstract

To efficiently store and utilize the stored heat.SOLUTION: In a heat storage mode, an energy storage device 100 heats solid particles using an electric heater 140 and stores the same in a high-temperature tank 180. In a power generation mode, the energy storage device stops the electric heater, supplies an oxygen containing gas to a fluidized bed device 130, supplies the solid particles from the high-temperature tank to the fluidized bed device, causes a first steam generator 160 to generate steam using heat of either one or both of the oxygen containing gas and the solid particles, and causes a stem turbine generator 210 to generate electricity. After the solid particles are supplied from the high-temperature tank to the fluidized bed device, the energy storage device causes a solid-gas separator 170 to separate the solid particles and supply the same to the fluidized bed device, supplies dried sludge from a silo 150 to the fluidized bed device, burns the dried sludge in the fluidized bed device, causes the first steam generator to generate steam with combustion heat of the dried sludge, and causes the steam turbine to generate electricity.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to energy storage devices. [Background technology]

[0002] The amount of generated power (hereinafter referred to as "generated power amount") does not necessarily match the amount of power required (hereinafter referred to as "demanded power amount"). For this reason, there may be a surplus of power (i.e., generated power amount - demanded power amount > 0) or a shortage of power (i.e., generated power amount - demanded power amount < 0, e.g., power shortage). In particular, with power generation using renewable energy such as wind power generation and solar power generation, there are many surpluses and shortages of power.

[0003] Therefore, a device has been developed that includes a brick block with a built-in electric heater and an internal flow path (for example, Patent Document 1). With the technology of Patent Document 1, when there is a surplus of electricity, the electric heater is operated to heat the brick block and store the heat. Then, with the technology of Patent Document 1, when electricity is needed (for example, when there is a power shortage), water is passed through the flow path and heated with the stored heat, and the heated water (steam) is used to rotate a turbine to generate electricity. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2008 / 0219651 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, in order to stabilize the power grid (to realize a smart grid), there is a demand for the development of technologies for storing and releasing heat, such as technologies that convert surplus electricity into heat, store it, and then use the stored heat when needed, to efficiently store heat and efficiently use the stored heat.

[0006] In view of the above problems, the present disclosure has an object to provide an energy storage device capable of efficiently storing heat and efficiently utilizing the stored heat. [Means for solving the problem]

[0007] In order to solve the above problems, an energy storage device according to one embodiment of the present disclosure includes a fluidized bed device in which a fluidized bed of non-flammable solid particles is formed by an oxygen-containing gas, a gas supply unit that supplies the oxygen-containing gas to the fluidized bed device, an electric heater that consumes electricity to heat either or both of the oxygen-containing gas supplied from the gas supply unit to the fluidized bed device and the oxygen-containing gas in the fluidized bed device, a silo that stores dried sludge, a fuel supply unit that supplies the dried sludge to the fluidized bed device, and a combustion device that is provided within the fluidized bed device to convert the heat of the oxygen-containing gas, the heat of the solid particles, and the heat generated by the combustion of the dried sludge. a first steam generator that generates steam by any one or more of the heats; a solid-gas separator that separates solid particles from a solid-gas mixture discharged from the fluidized bed equipment; a high-temperature tank and a low-temperature tank that store the solid particles separated by the solid-gas separator; a high-temperature particle supplying section that supplies the solid particles stored in the high-temperature tank to the fluidized bed equipment; a low-temperature particle supplying section that supplies the solid particles stored in the low-temperature tank to the fluidized bed equipment; a solid particle circulating section that supplies the solid particles separated by the solid-gas separator to the fluidized bed equipment without passing through the high-temperature tank and the low-temperature tank; and a control device that controls the gas supply unit, the electric heater, the fuel supply unit, the high-temperature particle supply unit, the low-temperature particle supply unit, and the solid particle circulation unit to set one of a plurality of operation modes including a heat storage mode in which electric energy is converted into thermal energy and stored, and a power generation mode in which thermal energy is converted into electric energy. In the heat storage mode, the control device controls the gas supply unit to supply an oxygen-containing gas to the fluidized bed device, controls the electric heater to heat the oxygen-containing gas, and controls the low-temperature particle supply unit to supply solid particles from a low-temperature tank to the fluidized bed device. supplying the oxygen-containing gas to the fluidized bed equipment, heating the solid particles with the oxygen-containing gas in the fluidized bed equipment, and supplying the solid particles separated by the solid-gas separator to the high-temperature tank; in a power generation mode, stopping the electric heater, controlling the gas supply unit to supply the oxygen-containing gas to the fluidized bed equipment, controlling the high-temperature particle supply unit to supply the solid particles from the high-temperature tank to the fluidized bed equipment; generating steam in the first steam generator by heat possessed by either or both of the oxygen-containing gas and the solid particles, generating electricity by the steam turbine generator; and when the supply of the solid particles from the high-temperature tank to the fluidized bed equipment is completed, controlling the solid particle circulating unit;The solid particles separated by the solid-gas separator are supplied to the fluidized bed apparatus, the fuel supply unit is controlled to supply dried sludge from the silo to the fluidized bed apparatus, the dried sludge is combusted in the fluidized bed apparatus, and steam is generated by the combustion heat of the dried sludge in the first steam generator, and electricity is generated by the steam turbine generator.

[0008] The energy storage device may also include a drying device that extracts a portion of the water vapor supplied to the steam turbine generator and dries the wet sludge, and the silo may store the dried sludge dried by the drying device.

[0009] The energy storage device may further include a second steam generator that receives solid particles from the high-temperature tank and generates water vapor by heat possessed by the solid particles, and the steam turbine generator generates power by the water vapor generated by the second steam generator, and the high-temperature particle supply unit supplies the solid particles stored in the high-temperature tank to the fluidized bed device via the second steam generator, and the control device, before the supply of solid particles from the high-temperature tank to the fluidized bed device is completed in the power generation mode, controls the high-temperature particle supply unit to supply solid particles from the high-temperature tank to the fluidized bed device via the second steam generator, and generates water vapor by heat possessed by the solid particles in the second steam generator, thereby generating power by the steam turbine generator.

[0010] In addition, the control device may stop the supply of steam from the first steam generator to the steam turbine generator and supply steam from the second steam generator to the steam turbine generator before the supply of solid particles from the high-temperature tank to the fluidized bed device is completed in the power generation mode.

[0011] In addition, the energy storage device may include a preheater that preheats the oxygen-containing gas with heat contained in the gas separated by the solid-gas separator, and the gas supply unit may supply the oxygen-containing gas preheated by the preheater to the fluidized bed device. Effect of the Invention

[0012] According to the present disclosure, it is possible to efficiently store heat and efficiently utilize the stored heat. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram illustrating an energy storage device according to this embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of a second steam generator according to the present embodiment. [Diagram 3] FIG. 3 is a diagram for explaining the processing of the control device in the heat storage mode according to this embodiment. [Figure 4] FIG. 4 is a diagram illustrating the processing of the control device in the first power generation mode according to this embodiment. [Diagram 5] FIG. 5 is a diagram illustrating the processing of the control device in the second power generation mode according to this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples for ease of understanding, and do not limit the present disclosure unless otherwise specified. In this specification and the drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanation. In addition, elements not directly related to the present disclosure are not illustrated.

[0015] Fig. 1 is a diagram for explaining an energy storage device 100 according to this embodiment. As shown in Fig. 1, the energy storage device 100 includes a gas supply unit 110, a preheater 120, a fluidized bed device 130, an electric heater 140, a silo 150, a fuel supply unit 152, a first steam generator 160, a water supply unit 162, a steam supply unit 164, a valve 166, a solid-gas separator 170, an exhaust pipe 172, a switching unit 174, a high-temperature tank 180, a high-temperature particle supply unit 182, a second steam generator 190, a water supply unit 200, a steam supply unit 202, a valve 204, a steam turbine generator 210, a drying device 220, a low-temperature tank 230, a low-temperature particle supply unit 232, a gas delivery unit 240, and a control device 250. In Fig. 1, the solid arrows indicate the flows of solid particles, dried sludge, and a solid-gas mixture, and the dashed arrows indicate the flows of gas and liquid.

[0016] The gas supply unit 110 supplies an oxygen-containing gas to a lower chamber 132b of a fluidized bed apparatus 130 (described later). The oxygen-containing gas is, for example, air or oxygen-enriched air. The gas supply unit 110 includes a blower 112 and a gas supply passage 114.

[0017] The blower 112 sucks in an oxygen-containing gas and discharges it into the lower chamber 132b. The suction side of the blower 112 is connected to a supply source of the oxygen-containing gas. The discharge side of the blower 112 is connected to a gas supply path 114.

[0018] The gas supply path 114 is a flow path that connects the discharge side of the blower 112 and the lower chamber 132b.

[0019] The preheater 120 preheats the oxygen-containing gas passing through the gas supply passage 114. Therefore, the gas supply unit 110 supplies the oxygen-containing gas preheated by the preheater 120 to the fluidized bed apparatus 130. In this embodiment, the preheater 120 is a heat exchanger that exchanges heat between the high-temperature gas (oxygen-containing gas or combustion exhaust gas) separated by the solid-gas separator 170 described below and the oxygen-containing gas passing through the gas supply passage 114. In other words, the preheater 120 preheats the oxygen-containing gas with the heat of the high-temperature gas separated by the solid-gas separator 170.

[0020] The fluidized bed apparatus 130 is supplied with an oxygen-containing gas from the gas supply unit 110, and is supplied with solid particles from a high temperature tank 180 and a low temperature tank 230, which will be described later. In the fluidized bed apparatus 130, a fluidized bed of solid particles is formed by the oxygen-containing gas supplied from the gas supply unit 110.

[0021] The solid particles are non-combustible. Examples of the solid particles include silica, alumina, barite sand (barium sulfate), partially calcined clay, glass spheres, and recovered petroleum catalysts. The solid particles are preferably either one or both of silica and alumina. When the solid particles are silica, the cost required for the solid particles can be reduced. In addition, by using desert sand or river sand as the solid particles (silica), it becomes possible to obtain the solid particles at low cost and easily. In addition, by using alumina, which has a relatively high melting point, the solid particles can be heated to a high temperature, and a higher energy storage density can be achieved.

[0022] The particle size of the solid particles is, for example, 0.01 mm to 10 mm. There is no limitation on the shape of the solid particles, and they may or may not be spherical.

[0023] In this embodiment, the fluidized bed apparatus 130 includes a storage vessel 132 and a distributor 134 .

[0024] The storage tank 132 is a hollow container. The storage tank 132 has, for example, a rectangular cylindrical shape. The gas supply path 114 is connected to the bottom of the storage tank 132.

[0025] The dispersion plate 134 is disposed substantially horizontally within the storage tank 132. The dispersion plate 134 is a plate with a plurality of holes formed therein. The size of the plurality of holes is such that solid particles cannot pass through or have difficulty passing through. The dispersion plate 134 divides the storage tank 132 into an upper chamber 132a and a lower chamber 132b. The upper chamber 132a is formed at the top of the storage tank 132. The lower chamber 132b is formed below the upper chamber 132a within the storage tank 132. The dispersion plate 134 functions as the bottom surface of the upper chamber 132a. The dispersion plate 134 also functions as the top surface of the lower chamber 132b.

[0026] A solid particle circulating section 174a, a pipe 184, and a pipe 234, which will be described later, are connected to the upper chamber 132a. Solid particles circulate within the upper chamber 132a through the solid particle circulating section 174a. Solid particles are supplied to the upper chamber 132a from the high temperature tank 180 through the pipe 184. Solid particles are supplied to the upper chamber 132a from the low temperature tank 230 through the pipe 234. In this manner, the solid particles are accommodated in the upper chamber 132a.

[0027] Further, a fuel supply pipe 154, which will be described later, is connected to the upper chamber 132a. Dried sludge is supplied to the upper chamber 132a through the fuel supply pipe 154.

[0028] An oxygen-containing gas is supplied to the lower chamber 132b from the gas supply unit 110 (blower 112). The oxygen-containing gas supplied to the lower chamber 132b is supplied to the upper chamber 132a through a plurality of holes formed in the dispersion plate .

[0029] The flow velocity of the oxygen-containing gas supplied to the upper chamber 132a by the gas supply unit 110 is equal to or greater than the terminal velocity of the solid particles in the upper chamber 132a. The solid particles are supplied from above through a plurality of holes formed in a dispersion plate 134 disposed on the bottom surface of the upper chamber 132a. Thus, the solid-gas mixture of the solid particles and the oxygen-containing gas passes through the upper chamber 132a from the bottom to the top (from the bottom surface to the top surface). In the upper chamber 132a, a fluidized bed of the solid particles and the oxygen-containing gas is formed, and the solid particles and the oxygen-containing gas are strongly stirred, so that the solid particles and the oxygen-containing gas come into contact with each other efficiently.

[0030] The electric heater 140 is provided in the upper chamber 132a. The electric heater 140 consumes electric power to heat the oxygen-containing gas and solid particles in the upper chamber 132a. The electric heater 140 is, for example, a resistance heating device (a device that utilizes heat generated from a conductor to which electric power is supplied). In this embodiment, the electric heater 140 is, for example, a ceramic heater having an electric heating wire (conductor) coated with ceramic.

[0031] The electric heater 140 can consume electric power generated by, for example, either one or both of a power generation system using renewable energy and a power generation system using a turbine generator. The power generation system using renewable energy is, for example, a solar thermal power generation system, a photovoltaic power generation system, a wind power generation system, or a hydroelectric power generation system. By consuming electric power generated by the power generation system using renewable energy, the electric power, which is often surplus, can be efficiently converted into heat.

[0032] The silo 150 stores dried sludge. The dried sludge is sludge that has been dried by a drying device 220, which will be described later. Sludge is a muddy solid obtained by agglomerating organic end products that are generated during the treatment process at a sewage treatment plant or during the wastewater treatment process at a factory. The sludge is, for example, sewage sludge, paper sludge, or food waste. The silo 150 is large enough to store an amount of dried sludge that can generate electricity for about one week using the steam turbine generator 210.

[0033] The fuel supply unit 152 supplies the dried sludge to the fluidized bed apparatus 130. The fuel supply unit 152 includes a fuel supply pipe 154 and a flow rate adjustment mechanism 156.

[0034] The fuel supply pipe 154 connects the lower part of the silo 150 and the fluidized bed apparatus 130. In this embodiment, the fuel supply unit 152 is connected to the upper chamber 132a of the fluidized bed apparatus 130.

[0035] The flow rate adjustment mechanism 156 is provided in the fuel supply pipe 154. The flow rate adjustment mechanism 156 adjusts the flow rate of the dried sludge supplied from the silo 150 to the fluidized bed apparatus 130. The flow rate adjustment mechanism 156 is, for example, a rotary valve.

[0036] The first steam generator 160 is provided in the fluidized bed apparatus 130. In this embodiment, the first steam generator 160 is provided in the upper chamber 132a of the fluidized bed apparatus 130. The first steam generator 160 is provided, for example, between a connection point of the fuel supply pipe 154, the solid particle circulation section 174a, the pipe 184, and the pipe 234 in the upper chamber 132a and a connection point of the discharge pipe 172. In this embodiment, the first steam generator 160 generates steam by any one or more of heat of the oxygen-containing gas, heat of the solid particles, and combustion heat of the dried sludge.

[0037] The water supply unit 162 supplies liquid water to the first steam generator 160. The water supply unit 162 is, for example, a pump. During the process of passing through the first steam generator 160, the liquid water exchanges heat with the fluidized bed (solid particles and combustion exhaust gas) formed in the upper chamber 132a, and is heated to become water vapor.

[0038] The water steam supply unit 164 supplies the water steam generated by the first steam generator 160 to a steam turbine generator 210 (described later). The water steam supply unit 164 is provided with a valve 166. The valve 166 is an opening and closing valve.

[0039] The solid-gas separator 170 separates solid particles from the solid-gas mixture discharged from the fluidized bed device 130. The solid-gas separator 170 is, for example, a cyclone or a filter.

[0040] The discharge pipe 172 connects the top of the upper chamber 132 a of the fluidized bed apparatus 130 to the solid-gas separator 170 .

[0041] The switching unit 174 switches the supply destination of the solid particles obtained by solid-gas separation by the solid-gas separator 170 to the high temperature tank 180, the low temperature tank 230, or the fluidized bed apparatus 130. The switching unit 174 includes a solid particle circulation unit 174a, pipes 174b and 174c, and valves 176a (solid particle circulation unit), 176b and 176c. The valves 176a to 176c are open / close valves.

[0042] The solid particle circulation unit 174a supplies the solid particles separated by the solid-gas separator 170 to the fluidized bed equipment 130 without passing through the high temperature tank 180 and the low temperature tank 230. The solid particle circulation unit 174a is, for example, a pipe connecting a solid particle discharge port of the solid-gas separator 170 and the upper chamber 132a of the fluidized bed equipment 130. The valve 176a is provided in the solid particle circulation unit 174a.

[0043] Pipe 174b connects a solid particle outlet of solid-gas separator 170 and high temperature tank 180. Valve 176b is provided on pipe 174b. Pipe 174c connects a solid particle outlet of solid-gas separator 170 and low temperature tank 230. Valve 176c is provided on pipe 174c. Valves 176a to 176c are exclusively opened and closed by control device 250 described later.

[0044] The high temperature tank 180 stores the solid particles separated from the solid-gas by the solid-gas separator 170. The high temperature tank 180 is, for example, a hopper. The high temperature tank 180 has a size capable of storing an amount of solid particles that can generate electricity for about half a day to a day by the steam turbine generator 210. The high temperature tank 180 is, for example, smaller than the silo 150.

[0045] The high-temperature particle supplying unit 182 supplies the solid particles stored in the high-temperature tank 180 to the fluidized bed apparatus 130 via a second steam generator 190 described below. The high-temperature particle supplying unit 182 includes a pipe 184 and a flow rate adjustment mechanism 186. The pipe 184 connects a lower part of the high-temperature tank 180 and an upper chamber 132a of the fluidized bed apparatus 130 via a container 192 of the second steam generator 190 described below.

[0046] The flow rate adjustment mechanism 186 is provided in the pipe 184. The flow rate adjustment mechanism 186 adjusts the flow rate of the solid particles supplied from the high temperature tank 180 to the fluidized bed apparatus 130. The flow rate adjustment mechanism 186 is, for example, a J-valve type loop seal or an L-valve type loop seal.

[0047] The second steam generator 190 is provided in the piping 184 between the flow rate control mechanism 186 and the fluidized bed apparatus 130. The second steam generator 190 receives solid particles from the high-temperature tank 180 and generates water vapor by the heat of the solid particles.

[0048] 2 is a diagram showing an example of a second steam generator 190 according to the present embodiment. As shown in FIG. 2, the second steam generator 190 includes a container 192, a dispersion plate 194a, an exhaust pipe 194b, a fluidizing gas supply unit 196, and a heat transfer tube 198.

[0049] The container 192 has a hollow shape. The container 192 has, for example, a square cylindrical shape. The dispersion plate 194a is provided substantially horizontally in the container 192. The dispersion plate 194a is a plate in which a plurality of holes are formed. The size of the plurality of holes is such that solid particles cannot pass through or have difficulty passing through. The dispersion plate 194a divides the inside of the container 192 into a storage chamber 192a and a wind box chamber 192b. The storage chamber 192a is formed in the upper part of the container 192. The wind box chamber 192b is formed below the storage chamber 192a in the container 192. The dispersion plate 194a functions as the bottom surface of the storage chamber 192a. The dispersion plate 194a also functions as the upper surface of the wind box chamber 192b.

[0050] In this embodiment, the pipe 184 connected to the high temperature tank 180 in the high temperature particle supply unit 182 penetrates the upper surface of the container 192. The upper end of the pipe 184 connected to the high temperature tank 180 is connected to the lower part of the high temperature tank 180. In addition, the lower end of the pipe 184 connected to the high temperature tank 180 is disposed in the accommodation chamber 192a. The lower end of the pipe 184 connected to the high temperature tank 180 is located lower than the upper end of the pipe 184 connected to the fluidized bed apparatus 130. In this embodiment, the lower end of the pipe 184 connected to the high temperature tank 180 is located near the dispersion plate 194a.

[0051] The solid particles stored in the high-temperature bath 180 are supplied to the storage chamber 192a through the pipe 184. Therefore, the solid particles are stored in the storage chamber 192a.

[0052] The fluidizing gas supply unit 196 is, for example, a pump, a blower, etc. The suction side of the fluidizing gas supply unit 196 is connected to a fluidizing gas supply source. The discharge side of the fluidizing gas supply unit 196 is connected to the wind box chamber 192b. The fluidizing gas is, for example, water vapor, air, carbon dioxide, or combustion exhaust gas. The fluidizing gas supply unit 196 supplies the fluidizing gas into the wind box chamber 192b so that the superficial velocity of the fluidizing gas supplied into the storage chamber 192a through the dispersion plate 194a is equal to or greater than the minimum fluidizing velocity Umf and less than the terminal velocity. As a result, the solid particles supplied from the high-temperature tank 180 are fluidized by the fluidizing gas, and a fluidized bed (bubble fluidized bed) is formed in the storage chamber 192a. In addition, since the superficial velocity of the fluidizing gas supplied by the fluidizing gas supply unit 196 is less than the terminal velocity, the solid particles do not scatter from the storage chamber 192a.

[0053] Furthermore, the pipe 184 connected to the fluidized bed apparatus 130 in the high-temperature particle supply unit 182 connects the accommodation chamber 192a to the lower part of the fluidized bed apparatus 130. The upper end of the pipe 184 connected to the fluidized bed apparatus 130 is connected to a part of the side surface of the container 192 near the upper surface of the fluidized bed in the accommodation chamber 192a. The lower end of the pipe 184 connected to the fluidized bed apparatus 130 is connected above the dispersion plate 134 in the fluidized bed apparatus 130.

[0054] As described above, a fluidized bed of solid particles is formed in the accommodation chamber 192a. Therefore, when solid particles are supplied from the high-temperature bath 180 through the pipe 184 connected to the high-temperature bath 180, the supplied amount of solid particles is pushed (overflows) into the pipe 184 connected to the fluidized bed apparatus 130. Then, the pushed-out solid particles are supplied to the fluidized bed apparatus 130 through the pipe 184 connected to the fluidized bed apparatus 130.

[0055] The heat transfer tube 198 is provided in the accommodation chamber 192a. A water supply unit 200 is connected to an inlet of the heat transfer tube 198. A steam turbine generator 210 is connected to an outlet of the heat transfer tube 198 via a water steam supply unit 202.

[0056] Further, an exhaust pipe 194b is connected to the upper surface of the container 192. The exhaust pipe 194b supplies the fluidizing gas to, for example, a heat utilization device (not shown). The heat utilization device is, for example, a gas turbine generator, a steam turbine generator (boiler), a boiler that provides steam, a furnace (furnace, kiln), or an air conditioning device.

[0057] The water supply unit 200 supplies liquid water to the heat transfer tube 198. The water supply unit 200 is, for example, a pump. During the process of passing through the heat transfer tube 198, the liquid water exchanges heat with the fluidized bed (solid particles and fluidizing gas) formed in the accommodation chamber 192a, and is heated to become water vapor.

[0058] The water steam supply unit 202 supplies the water steam generated in the heat transfer tube 198 of the second steam generator 190 to the steam turbine generator 210. The water steam supply unit 202 is provided with a valve 204. The valve 204 is an opening and closing valve.

[0059] Returning to FIG. 1, the steam turbine generator 210 generates electricity using the steam generated by the first steam generator 160 and the steam generated by the second steam generator 190 .

[0060] The drying device 220 extracts a portion of the water vapor supplied to the steam turbine generator 210 and dries the wet sludge. The wet sludge is, for example, sludge containing about 80 mass % water. The wet sludge is, for example, dehydrated sludge (dehydrated cake). The dried sludge dried by the drying device 220 is stored in the silo 150.

[0061] The steam supply pipe 222 is a pipe that connects the steam turbine generator 210 and the drying device 220. A valve 224 is provided in the steam supply pipe 222. The valve 224 is an opening and closing valve.

[0062] The low temperature tank 230 stores the solid particles separated by the solid-gas separator 170. The solid particles are supplied to the low temperature tank 230 at a timing different from that of the high temperature tank 180. The low temperature tank 230 is, for example, a hopper. The low temperature tank 230 has approximately the same size as the high temperature tank 180.

[0063] The low-temperature particle supply unit 232 supplies the solid particles stored in the low-temperature tank 230 to the fluidized bed apparatus 130. The low-temperature particle supply unit 232 includes a pipe 234 and a flow rate adjustment mechanism 236. The pipe 234 connects a lower part of the low-temperature tank 230 and an upper chamber 132a of the fluidized bed apparatus 130. In this embodiment, an upper end of the pipe 234 is connected to a lower part of the low-temperature tank 230. A lower end of the pipe 234 is connected above the dispersion plate 134 in the fluidized bed apparatus 130.

[0064] The flow rate adjustment mechanism 236 is provided in the pipe 234. The flow rate adjustment mechanism 236 adjusts the flow rate of the solid particles supplied from the low-temperature bath 230 to the fluidized bed apparatus 130. The flow rate adjustment mechanism 236 is, for example, a rotary valve.

[0065] The gas delivery unit 240 supplies the gas (oxygen-containing gas or combustion exhaust gas) separated by the solid-gas separator 170 to the preheater 120. The gas delivery unit 240 is a pipe that connects the gas exhaust port of the solid-gas separator 170 and the preheater 120.

[0066] The control device 250 is composed of a semiconductor integrated circuit including a CPU (Central Processing Unit). The control device 250 reads out programs and parameters for operating the CPU from a ROM. The control device 250 manages and controls the entire energy storage device 100 in cooperation with a RAM as a work area and other electronic circuits.

[0067] In this embodiment, the control device 250 controls the gas supply unit 110 (blower 112), the electric heater 140, the fuel supply unit 152 (flow rate adjustment mechanism 156), the water supply unit 162, the valve 166, the switching unit 174 (valves 176a to 176c), the high-temperature particle supply unit 182 (flow rate adjustment mechanism 186), the fluidizing gas supply unit 196, the water supply unit 200, the valve 204, the steam turbine generator 210, the drying device 220, the valve 224, and the low-temperature particle supply unit 232 (flow rate adjustment mechanism 236).

[0068] In this embodiment, during a period when there is surplus power (i.e., generated power amount - demanded power amount > predetermined value (e.g. 0)), the control device 250 converts the surplus power (electrical energy) into thermal energy and stores it. Hereinafter, the operation mode in which electrical energy is converted into thermal energy and stored is referred to as the thermal storage mode. On the other hand, when electrical power is needed, the control device 250 operates the steam turbine generator 210 (generates electricity) using the stored thermal energy. Hereinafter, the operation mode in which thermal energy is converted into electrical energy by the steam turbine generator 210 is referred to as the power generation mode.

[0069] In the initial state, the blower 112, the electric heater 140, the water supply units 162, 200, and the fluidizing gas supply unit 196 are stopped, and the valves 166, 176a-176c, 204, and 224, and the flow rate adjustment mechanisms 156, 186, and 236 are closed. In the initial state, the solid particles are stored in the low-temperature tank 230. The processing of the control device 250 in the heat storage mode and the power generation mode will be described below.

[0070] [Heat storage mode] 3 is a diagram for explaining the processing of the control device 250 in the heat storage mode according to this embodiment. For ease of understanding, components that are not used in the heat storage mode are omitted in FIG.

[0071] The control device 250 closes the valves 166, 176a, 176c, 204, 224 and the flow rate adjustment mechanisms 156, 186. The control device 250 stops the water supply unit 162, the fluidizing gas supply unit 196, and the water supply unit 200. As shown in Fig. 3, the control device 250 also operates the blower 112 and the electric heater 140. The control device 250 opens the valve 176b and opens the flow rate adjustment mechanism 236 to adjust the opening degree.

[0072] Then, the electric heater 140 consumes surplus electricity. The oxygen-containing gas supplied to the fluidized bed device 130 by the blower 112 is heated by the electric heater 140. The electric heater 140 heats the oxygen-containing gas to a first temperature. The first temperature is lower than the heat-resistant temperature of the solid particles, and is a temperature that satisfies the required temperature of the steam turbine generator 210 in a first power generation mode described later. In the fluidized bed device 130, the oxygen-containing gas at the first temperature exchanges heat with the low-temperature solid particles supplied from the low-temperature tank 230, thereby heating the solid particles to a second temperature. In other words, the first temperature is a temperature at which the solid particles can be heated to a second temperature or higher in the heat storage mode. The second temperature is a temperature at which the second steam generator 190 can generate steam that satisfies the required temperature (fourth temperature) of the steam turbine generator 210 in the first power generation mode. When the solid particles are silica, the heat-resistant temperature of the solid particles is, for example, 1600°C. The second temperature is lower than the first temperature, but the temperature difference is small. The temperature difference between the second temperature and the first temperature is, for example, about 50° C. The first temperature is, for example, 1100° C.

[0073] Also, low-temperature solid particles are supplied from the low-temperature tank 230 to the fluidized bed device 130. The low-temperature tank 230 stores, for example, solid particles at room temperature (for example, 25°C). Therefore, in the fluidized bed device 130, the high-temperature oxygen-containing gas and the low-temperature solid particles are strongly stirred, and heat exchange occurs between the high-temperature oxygen-containing gas and the low-temperature solid particles. As a result, the solid particles are heated by the oxygen-containing gas, and the oxygen-containing gas is cooled by the solid particles. At the outlet of the fluidized bed device 130, the temperature of the solid particles and the temperature of the oxygen-containing gas become almost equal (the second temperature).

[0074] The solid-gas separator 170 separates the solid-gas mixture discharged from the fluidized bed device 130 into solid and gas. The high-temperature solid particles (solid particles at a second temperature) obtained by the solid-gas separation are supplied to the high-temperature tank 180 through the pipe 174b. The high-temperature tank 180 stores the high-temperature solid particles.

[0075] Meanwhile, the oxygen-containing gas of the second temperature separated from the solid-gas separator 170 is supplied to the preheater 120 through the gas delivery section 240. The preheater 120 exchanges heat between the oxygen-containing gas of the second temperature supplied from the solid-gas separator 170 through the gas delivery section 240 and the oxygen-containing gas supplied to the fluidized bed device 130 by the blower 112. Therefore, the oxygen-containing gas supplied to the fluidized bed device 130 by the blower 112 is heated to a third temperature by the oxygen-containing gas of the second temperature. The third temperature is a temperature higher than room temperature. That is, the preheater 120 can preheat the oxygen-containing gas before it is supplied to the fluidized bed device 130 with the heat of the oxygen-containing gas discharged from the fluidized bed device 130. The oxygen-containing gas supplied from the solid-gas separator 170 is heat exchanged in the preheater 120 and then supplied to a heat utilization device (not shown).

[0076] In this way, in the heat storage mode, the surplus electricity is converted into heat and first transferred to the oxygen-containing gas. Then, heat exchange occurs between the high-temperature oxygen-containing gas and the low-temperature solid particles, and the heat is transferred to the solid particles. In this way, the surplus electricity is converted into thermal energy and is retained (stored) in the solid particles. Note that the heat capacity of the solid particles is greater than that of the oxygen-containing gas (air), so the heat storage density (J / m3 ) is higher than oxygen-containing gases.

[0077] The controller 250 adjusts the aperture of the flow rate adjustment mechanism 236 based on the amount of surplus power (hereinafter referred to as "surplus power amount"). Specifically, when the electric heater 140 converts the surplus power amount into thermal energy and the solid particles are heated with this thermal energy (via the oxygen-containing gas), the amount of solid particles that will reach the second temperature is determined. Therefore, the controller 250 adjusts the aperture of the flow rate adjustment mechanism 236 so that the determined amount of solid particles is supplied to the fluidized bed device 130.

[0078] As a result, even if the amount of surplus power fluctuates (if the amount of surplus power fluctuates over time), the temperature of the solid particles stored in the high-temperature tank 180 can be steadily maintained at the second temperature. In other words, it is possible to respond to fluctuations in the amount of surplus power. Therefore, in a first power generation mode described below, it is possible to supply steam at a fourth temperature that satisfies the required temperature to the steam turbine generator 210 without using additional energy (for example, without burning auxiliary fuel).

[0079] [Power generation mode] In the power generation mode of this embodiment, the control device 250 first sets the operation mode to the first power generation mode, and when the first power generation mode ends, sets the operation mode to the second power generation mode.

[0080] [First power generation mode] 4 is a diagram for explaining the processing of the control device 250 in the first power generation mode according to this embodiment. For ease of understanding, components that are not used in the first power generation mode are omitted in FIG.

[0081] The control device 250 closes the valves 166, 176a, 176b and the flow rate adjustment mechanisms 156, 236. The control device 250 stops the electric heater 140 and the water supply unit 162. Furthermore, as shown in Fig. 4, the control device 250 opens the valves 176c, 204, 224 and opens the flow rate adjustment mechanism 186 to adjust the opening degree. The control device 250 operates the blower 112, the fluidizing gas supply unit 196, the water supply unit 200, and the drying device 220.

[0082] Then, high-temperature solid particles (solid particles at a second temperature) are supplied from the high-temperature tank 180 to the second steam generator 190. In addition, the fluidizing gas supply unit 196 supplies the fluidizing gas into the accommodation chamber 192a. As a result, a fluidized bed of high-temperature solid particles is formed in the second steam generator 190. In addition, water is supplied from the water supply unit 200 to the heat transfer tube 198. Therefore, in the second steam generator 190, heat exchange is performed between the water and the high-temperature solid particles. As a result, the water is heated by the solid particles, and the solid particles are cooled by the water. In this way, the water steam generated in the second steam generator 190 is supplied to the steam turbine generator 210. As a result, the steam turbine generator 210 generates electric power. The temperature of the water steam supplied to the steam turbine generator 210 and the temperature of the solid particles discharged from the second steam generator 190 are approximately equal to each other, and are at a fourth temperature. The fourth temperature is a predetermined temperature that satisfies the required temperature of the steam turbine generator 210 and is lower than the second temperature.

[0083] Then, in the second steam generator 190, the solid particles cooled from the second temperature to the fourth temperature by heat exchange with water are supplied to the fluidized bed apparatus 130 through the pipe 184 connected to the fluidized bed apparatus 130. Also, an oxygen-containing gas is supplied to the fluidized bed apparatus 130 from the blower 112. Therefore, in the fluidized bed apparatus 130, heat exchange is performed between the low-temperature oxygen-containing gas and the high-temperature solid particles. As a result, the oxygen-containing gas is heated by the solid particles, and the solid particles are cooled by the gas. Thus, in the fluidized bed apparatus 130, the temperatures of the solid particles and the oxygen-containing gas become approximately equal. For example, the temperatures of the solid particles and the oxygen-containing gas become a fifth temperature lower than the fourth temperature.

[0084] The solid-gas separator 170 separates the solid-gas mixture discharged from the fluidized bed apparatus 130 into solid and gas. The high-temperature (fifth temperature) oxygen-containing gas separated from the solid-gas mixture is supplied to the preheater 120 through the gas discharge section 240. The preheater 120 exchanges heat between the oxygen-containing gas at the fifth temperature supplied from the solid-gas separator 170 through the gas discharge section 240 and the oxygen-containing gas supplied to the fluidized bed apparatus 130 by the blower 112. Therefore, the oxygen-containing gas supplied to the fluidized bed apparatus 130 by the blower 112 is heated to a sixth temperature by the oxygen-containing gas at the fifth temperature. The sixth temperature is a temperature higher than room temperature (e.g., 25°C). That is, the preheater 120 can preheat the oxygen-containing gas before it is supplied to the fluidized bed apparatus 130 by the heat of the oxygen-containing gas discharged from the fluidized bed apparatus 130. The oxygen-containing gas supplied from the solid-gas separator 170 is heat exchanged in the preheater 120, and then supplied to a heat utilization device (not shown).

[0085] On the other hand, the solid particles at the fifth temperature after solid-gas separation are supplied to the low-temperature tank 230 through the pipe 174c. The low-temperature tank 230 stores the solid particles at the fifth temperature.

[0086] Thus, in the first power generation mode, heat exchange occurs between high-temperature (second temperature) solid particles and low-temperature water in the second steam generator 190 to generate steam. Then, when necessary (for example, during a period of power shortage), the high-temperature (fourth temperature) steam can be used to generate power in the steam turbine generator 210.

[0087] The control device 250 adjusts the opening degree of the flow rate adjustment mechanism 186 based on the required temperature and required flow rate of the steam turbine generator 210. Specifically, when the water supply unit 200 supplies water to the heat transfer tube 198 of the second steam generator 190 at the required flow rate of the steam turbine generator 210 and heats the water with solid particles at the second temperature stored in the high-temperature tank 180, the amount of solid particles for heating the water to generate steam at a fourth temperature is determined. Therefore, the control device 250 adjusts the opening degree of the flow rate adjustment mechanism 186 so that the determined amount of solid particles is supplied to the second steam generator 190.

[0088] This allows the temperature of the steam supplied to the steam turbine generator 210 to be the required temperature of the steam turbine generator 210. Therefore, without using additional energy (for example, without burning auxiliary fuel), it is possible to stably supply steam at a fourth temperature that satisfies the required temperature to the steam turbine generator 210. Even if the required temperature of the steam turbine generator 210 (for example, the required amount of power generation) fluctuates over time, this can be accommodated by adjusting the supply amount of solid particles.

[0089] Furthermore, in the first power generation mode, the control device 250 opens the valve 224. Then, a part of the steam supplied to the steam turbine generator 210 is extracted and supplied to the drying device 220.

[0090] This allows the wet sludge to be dried without consuming power in the first power generation mode, making it possible to produce dried sludge with reduced energy consumption.

[0091] In addition, the drying device 220 can be used as a condenser for the steam turbine generator 210. This makes it possible to improve the efficiency of power generation by the steam turbine generator 210 while drying the wet sludge.

[0092] [Second power generation mode] The control device 250 switches the operation mode from the first power generation mode to the second power generation mode when the supply of solid particles from the high temperature tank 180 to the second steam generator 190 is completed. In other words, the control device 250 switches the operation mode from the first power generation mode to the second power generation mode when all the solid particles stored in the high temperature tank 180 are supplied to the second steam generator 190 (when the high temperature tank 180 becomes empty).

[0093] 5 is a diagram for explaining the processing of the control device 250 in the second power generation mode according to this embodiment. For ease of understanding, components that are not used in the second power generation mode are omitted in FIG.

[0094] The control device 250 closes the valves 176b, 176c, and 204 and the flow rate adjustment mechanisms 186 and 236. The control device 250 stops the electric heater 140 and the water supply unit 200. As shown in Fig. 5, the control device 250 also opens the valves 166, 176a, and 224, and opens the flow rate adjustment mechanism 156 to adjust the opening degree. The control device 250 operates the blower 112, the fluidizing gas supply unit 196, the water supply unit 162, and the drying device 220.

[0095] Then, the solid particles separated by the solid-gas separator 170 are supplied to the fluidized bed equipment 130 by the solid particle circulating unit 174a. As a result, the solid particles are circulated through the fluidized bed equipment 130, the solid-gas separator 170, and the solid particle circulating unit 174a. Then, an oxygen-containing gas is supplied to the fluidized bed equipment 130 by the gas supplying unit 110, and a fluidized bed of solid particles is formed in the fluidized bed equipment 130.

[0096] Furthermore, in the initial state of the second power generation mode, the control device 250 supplies auxiliary fuel to the fluidized bed device 130 and burns the auxiliary fuel, whereby the fluidized bed in the fluidized bed device 130 becomes hot.

[0097] Then, when the fuel supply unit 152 supplies the dried sludge from the silo 150 to the fluidized bed apparatus 130, the dried sludge is combusted by a fluidized bed of high-temperature solid particles in the fluidized bed apparatus 130. That is, in the second power generation mode, the fluidized bed apparatus 130 functions as a fluidized bed combustion furnace. Then, the solid particles are heated by the combustion heat of the dried sludge. When the temperature of the solid particles reaches a seventh temperature, the control device 250 stops the supply of auxiliary fuel. The seventh temperature is the temperature of the solid particles at which the dried sludge can be combusted even when the supply of auxiliary fuel is stopped.

[0098] Thus, a fluidized bed of solid particles and flue gas at the seventh temperature is formed within the fluidized bed apparatus 130 .

[0099] Also, water is supplied from the water supply unit 162 to the first steam generator 160. Therefore, in the first steam generator 160, heat exchange occurs between the combustion heat of the dried sludge (high-temperature solid particles and high-temperature combustion exhaust gas) and the water. As a result, the water is heated by the solid particles, and the solid particles are cooled by the water. Thus, the water steam generated in the first steam generator 160 is supplied to the steam turbine generator 210. As a result, the steam turbine generator 210 generates electric power. The temperature of the water steam supplied to the steam turbine generator 210 and the temperature of the solid-gas mixture discharged from the fluidized bed device 130 are approximately equal to each other, and are the eighth temperature. The eighth temperature is a predetermined temperature that satisfies the required temperature of the steam turbine generator 210, and is lower than the seventh temperature.

[0100] Then, in the first steam generator 160, the solid-gas mixture cooled from the seventh temperature to the eighth temperature by heat exchange with water is discharged to the solid-gas separator 170. The solid-gas separator 170 separates the solid-gas mixture discharged from the fluidized bed apparatus 130 into solid and gas. The high-temperature (eighth temperature) combustion exhaust gas from the solid-gas separation is supplied to the preheater 120 through the gas delivery section 240. The preheater 120 exchanges heat between the eighth temperature combustion exhaust gas supplied from the solid-gas separator 170 through the gas delivery section 240 and the oxygen-containing gas supplied to the fluidized bed apparatus 130 by the blower 112. Therefore, the oxygen-containing gas supplied to the fluidized bed apparatus 130 by the blower 112 is heated to the ninth temperature by the eighth temperature combustion exhaust gas. The ninth temperature is a temperature higher than room temperature. That is, the preheater 120 can preheat the oxygen-containing gas before it is supplied to the fluidized bed apparatus 130, by using the heat of the combustion exhaust gas discharged from the fluidized bed apparatus 130. The combustion exhaust gas supplied from the solid-gas separator 170 is subjected to heat exchange in the preheater 120, and then supplied to a heat utilization device (not shown).

[0101] On the other hand, the solid particles having the eighth temperature after solid-gas separation are returned to the fluidized bed apparatus 130 through the solid particle circulation section 174a.

[0102] Thus, in the second power generation mode, the dried sludge is combusted, and the resulting combustion heat generates steam in the first steam generator 160. Then, when necessary (for example, during a period when power is insufficient), the high-temperature (eighth temperature) steam can be used to generate power in the steam turbine generator 210.

[0103] The control device 250 adjusts the aperture of the flow rate adjustment mechanism 156 based on the required temperature and required flow rate of the steam turbine generator 210. Specifically, when the water supply unit 162 supplies water to the first steam generator 160 at the required flow rate of the steam turbine generator 210 and heats the water with the combustion heat of the dried sludge, the amount of dried sludge for heating the water to generate steam at the eighth temperature is determined. Therefore, the control device 250 adjusts the aperture of the flow rate adjustment mechanism 156 so that the determined amount of dried sludge is supplied to the fluidized bed equipment 130.

[0104] Furthermore, in the second power generation mode, the control device 250 opens the valve 224. Then, a part of the steam supplied to the steam turbine generator 210 is extracted and supplied to the drying device 220.

[0105] This allows the wet sludge to be dried without consuming power in the second power generation mode, making it possible to produce dried sludge with reduced energy consumption.

[0106] In addition, the drying device 220 can be used as a condenser for the steam turbine generator 210. This makes it possible to improve the efficiency of power generation by the steam turbine generator 210 while drying the wet sludge.

[0107] As described above, the energy storage device 100 according to this embodiment converts surplus power into thermal energy and stores it in solid particles. This allows the energy storage device 100 to store energy at a lower cost than conventional technologies that store surplus power in secondary batteries or convert surplus power into hydrogen. Furthermore, the energy storage device 100 can convert the stored energy into electrical energy at high speed when needed (for example, when there is a power shortage), compared to conventional technologies that convert surplus power into hydrogen and store it.

[0108] Furthermore, compared to the conventional technology of storing heat in brick blocks, the energy storage device 100 can store solid particles at a specified second temperature in the heat storage mode by adjusting the amount of solid particles to be stored, even if the surplus electricity fluctuates.

[0109] In addition, in the second power generation mode, the energy storage device 100 can generate power using heat from combustion of dried sludge that was conventionally discarded. This allows the energy storage device 100 to generate power at low cost.

[0110] Furthermore, the energy storage device 100 can generate power not from fossil fuels but from the combustion heat of dried sludge. This allows the energy storage device 100 to reduce carbon dioxide emissions compared to when power is generated by burning fossil fuels.

[0111] Furthermore, the energy storage device 100 combusts dry sludge instead of wet sludge, which allows the energy storage device 100 to reduce the energy required for combusting sludge.

[0112] The energy storage device 100 also includes a drying device 220 and a silo 150. This allows the energy storage device 100 to use dried sludge as an energy storage material. Therefore, the energy storage device 100 can store energy more efficiently than when energy is stored in solid particles as heat. To be more specific, high-temperature solid particles store energy as sensible heat, and therefore dissipate heat as time passes. Therefore, the thermal energy stored in the solid particles decreases as time passes. In contrast, dried sludge does not store energy as sensible heat, but stores energy as chemical energy. Therefore, the energy of dried sludge does not decrease as time passes. Therefore, by using dried sludge as an energy storage material, the energy storage device 100 can store energy more efficiently than when energy is stored in solid particles as heat.

[0113] Although the embodiments have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to the above-described embodiments. It is clear that a person skilled in the art can think of various modified or altered examples within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present disclosure.

[0114] For example, in the above-described embodiment, the gas supply unit 110 is described as including the blower 112. However, the gas supply unit 110 is not limited to a specific configuration as long as it can supply an oxygen-containing gas to the fluidized bed apparatus 130. For example, the gas supply unit 110 may include a compressed gas source (e.g., a compressed air source) or a pump instead of the blower 112.

[0115] In the above embodiment, the configuration in which the gas is supplied from the bottom surface of the fluidized bed apparatus 130 has been described as an example. However, the oxygen-containing gas may be supplied from below the supply point of the solid particles in the fluidized bed apparatus 130. For example, the oxygen-containing gas may be supplied from the lower part of the fluidized bed apparatus 130. Furthermore, the gas supply unit 110 may supply an oxygen-containing gas at normal pressure, or may supply a pressurized oxygen-containing gas.

[0116] In the above embodiment, the second steam generator 190 is described as forming a fluidized bed of solid particles. This allows the second steam generator 190 to efficiently generate steam using heat from the solid particles in the first power generation mode. However, the second steam generator 190 is not limited to a specific configuration as long as it can generate steam by exchanging heat between the solid particles and water. For example, the second steam generator 190 may be configured to form a moving bed of solid particles.

[0117] In the above embodiment, the control device 250 sets the period when there is a surplus of power (power generation amount-power demand amount>predetermined value (e.g., 0)) to the heat storage mode. However, the control device 250 may set the mode to the heat storage mode when it is necessary to convert power to other energy (e.g., when it is necessary to consume power to stabilize the power grid).

[0118] In the above embodiment, the electric heater 140 is provided in the fluidized bed apparatus 130. However, the electric heater 140 may heat the oxygen-containing gas supplied from the gas supply unit 110 to the fluidized bed apparatus 130. For example, the electric heater 140 may be provided between the preheater 120 and the fluidized bed apparatus 130 in the gas supply passage 114.

[0119] In the above embodiment, the control device 250 sets the operation mode to any one of the heat storage mode, the first power generation mode, and the second power generation mode. However, the control device 250 may set the operation mode to one of a plurality of operation modes including the heat storage mode, the first power generation mode, the second power generation mode, and another operation mode.

[0120] In addition, in the first power generation mode of the above embodiment, the control device 250 stops the supply of water steam from the first steam generator 160 to the steam turbine generator 210 and supplies water steam from the second steam generator 190 to the steam turbine generator 210. That is, in the first power generation mode, the control device 250 stops the operation of the first steam generator 160 and operates the second steam generator 190. However, in the first power generation mode, the control device 250 may operate the first steam generator 160 and the second steam generator 190 and supply water steam from the first steam generator 160 and the second steam generator 190 to the steam turbine generator 210. This allows the energy storage device 100 to improve the power generation efficiency of the steam turbine generator 210 in the first power generation mode.

[0121] In the above embodiment, the energy storage device 100 includes the second steam generator 190. However, the second steam generator 190 is not an essential component. In the case where the second steam generator 190 is not included, the high-temperature particle supply unit 182 directly supplies the solid particles stored in the high-temperature tank 180 to the fluidized bed device 130. In this case, the control device 250 controls the high-temperature particle supply unit 182 in the first power generation mode to supply the solid particles from the high-temperature tank 180 to the fluidized bed device 130, and generates steam in the first steam generator 160 using the heat of the oxygen-containing gas and the heat of the solid particles, and causes the steam turbine generator 210 to generate power. As a result, the energy storage device 100 can generate steam in the first power generation mode using the first steam generator 160 without including the second steam generator 190, and can generate power using the steam using the steam turbine generator 210.

[0122] In the above embodiment, the energy storage device 100 includes the drying device 220. However, the drying device 220 is not an essential component.

[0123] This disclosure can, for example, contribute to Sustainable Development Goal (SDG) 7: "Ensure access to affordable, reliable, sustainable and modern energy." [Explanation of symbols]

[0124] 100 Energy storage device 110 Gas supply section 120 Preheater 130 Fluidized Bed Equipment 140 Electric heater 150 Silo 152 Fuel supply section 160 No. 1 Steam Generator 170 Solid-gas separator 174a Solid particle circulation section 180 High temperature bath 182 High temperature particle supply section 190 No. 2 Steam Generator 210 Steam Turbine Generator 220 Drying equipment 230 Cryostat 232 Low Temperature Particle Supply Unit 250 Control device

Claims

1. a fluidized bed device in which a fluidized bed of non-combustible solid particles is formed by an oxygen-containing gas; a gas supply unit that supplies the oxygen-containing gas to the fluidized bed apparatus; an electric heater that consumes electric power to heat either or both of the oxygen-containing gas supplied from the gas supply unit to the fluidized bed apparatus and the oxygen-containing gas in the fluidized bed apparatus; a silo for storing dried sludge; a fuel supply unit that supplies the dried sludge to the fluidized bed apparatus; a first steam generator provided in the fluidized bed apparatus and configured to generate steam using one or more of heat from the oxygen-containing gas, heat from the solid particles, and heat from combustion of the dried sludge; a solid-gas separator for separating the solid particles from the solid-gas mixture discharged from the fluidized bed apparatus; a high-temperature tank and a low-temperature tank for storing the solid particles separated by the solid-gas separator; a high-temperature particle supply unit that supplies the solid particles stored in the high-temperature tank to the fluidized bed apparatus; a low-temperature particle supply unit that supplies the solid particles stored in the low-temperature tank to the fluidized bed apparatus; a solid particle circulation section that supplies the solid particles separated by the solid-gas separator to the fluidized bed apparatus without passing through the high-temperature tank and the low-temperature tank; a steam turbine generator that generates electricity using the steam generated by the first steam generator; a control device that controls the gas supply unit, the electric heater, the fuel supply unit, the high-temperature particle supply unit, the low-temperature particle supply unit, and the solid particle circulator to set one of a plurality of operation modes including a heat storage mode in which electric energy is converted into thermal energy and stored, and a power generation mode in which thermal energy is converted into electric energy; Equipped with The control device includes: In the heat storage mode, Controlling the gas supply unit to supply the oxygen-containing gas to the fluidized bed apparatus; Controlling the electric heater to heat the oxygen-containing gas; controlling the low-temperature particle supply unit to supply the solid particles from the low-temperature tank to the fluidized bed device, and heating the solid particles with the oxygen-containing gas in the fluidized bed device; Supplying the solid particles separated by the solid-gas separator to the high-temperature tank; In the power generation mode, Stopping the electric heater; Controlling the gas supply unit to supply the oxygen-containing gas to the fluidized bed apparatus; supplying the solid particles from the high-temperature tank to the fluidized bed apparatus by controlling the high-temperature particle supply unit; generating steam in the first steam generator by heat possessed by either or both of the oxygen-containing gas and the solid particles; and generating electricity using the steam turbine generator. when the supply of the solid particles from the high temperature tank to the fluidized bed equipment is completed, the solid particle circulation unit is controlled to supply the solid particles separated by the solid-gas separator to the fluidized bed equipment, the fuel supply unit is controlled to supply the dried sludge from the silo to the fluidized bed equipment, the dried sludge is combusted in the fluidized bed equipment, water steam is generated by the combustion heat of the dried sludge in the first steam generator, and electricity is generated by the steam turbine generator.

2. a drying device that extracts a portion of the water vapor supplied to the steam turbine generator and dries the wet sludge, The energy storage device according to claim 1 , wherein the silo stores the dried sludge dried by the drying device.

3. a second steam generator configured to receive the solid particles from the high-temperature tank and generate water vapor by heat of the solid particles, the steam turbine generator generates electricity using the steam generated by the second steam generator; the high-temperature particle supply unit supplies the solid particles stored in the high-temperature tank to the fluidized bed apparatus via the second steam generator, 3. The energy storage device according to claim 1, wherein the control device controls the high-temperature particle supplying unit to supply the solid particles from the high-temperature tank to the fluidized bed device via the second steam generator before the supply of the solid particles from the high-temperature tank to the fluidized bed device is completed in the power generation mode, and generates water steam in the second steam generator by using heat possessed by the solid particles to generate power using the steam turbine generator.

4. 4. The energy storage device according to claim 3, wherein the control device stops the supply of steam from the first steam generator to the steam turbine generator and causes the second steam generator to supply steam to the steam turbine generator before the supply of the solid particles from the high-temperature tank to the fluidized bed device is completed in the power generation mode.

5. A preheater is provided for preheating the oxygen-containing gas with heat of the gas separated by the solid-gas separator, The energy storage device according to claim 1 or 2, wherein the gas supply unit supplies the oxygen-containing gas preheated by the preheater to the fluidized bed device.

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