Heat storage device and heat utilization system

Abstract

To efficiently take out heat from a granular heat storage material.SOLUTION: A heat storage device 10 stores a granular heat storage material 22 containing alkaline earth metal in a container body 21. A first introduction unit 23 is provided in a lower part of the container body 21, a discharge port 25 is provided in an upper part of the container body 21, and a second introduction unit 24 is provided at a position between the first introduction unit 23 and the discharge port 25. At heat radiation, when a prescribed condition is satisfied after supply of low temperature gas containing steam to the first introduction unit 23 is started, a supply amount of the low temperature gas to the first introduction unit 23 is decreased or the supply is stopped, and supply of the low temperature gas to the second introduction unit 24 is started.SELECTED DRAWING: Figure 4A

Description

[Technical field]

[0001] The present invention relates to a heat storage device that stores and releases heat, and a heat utilization system having a heat storage device. [Background technology]

[0002] Conventionally, there have been studies on technologies that store heat in a heat storage material and release the heat when needed or at a different location. Known heat storage materials include zeolite, HASClay, etc., which utilize water vapor adsorption, and erythritol, sodium acetate, etc., which utilize latent heat. However, there are few practical examples of heat storage materials that utilize water vapor adsorption and heat storage materials that utilize latent heat, due to reasons such as low heat storage density, low temperatures during heat storage and heat release, and large heat release loss.

[0003] On the other hand, heat storage materials that utilize chemical reactions are also known. For example, Patent Document 1 discloses a removable heat storage container that uses a magnesium hydroxide-based heat storage material. Heat storage materials that utilize chemical reactions do not have the disadvantages of heat storage materials that utilize adsorption or latent heat. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-124946 A Summary of the Invention [Problem to be solved by the invention]

[0005] By the way, when water vapor is applied to a granular heat storage material containing magnesium oxide or calcium oxide in a heat-storing state to release heat, it has been studied in the past how to efficiently extract heat from the entire heat storage material, but this has not been sufficient. Therefore, the present invention aims to efficiently extract heat from a granular heat storage material containing an alkaline earth metal. [Means for solving the problem]

[0006] A first aspect of the present invention is a heat storage device that stores and releases heat, comprising a container body that stores a granular heat storage material containing an alkaline earth metal; A low-temperature gas containing water vapor is supplied to the heat storage material to release heat. To the heat storage material Hand a first introduction part for supplying gas to the container body, and an exhaust port for exhausting gas from the container body; and at a position between the first introduction part and the exhaust port, A low-temperature gas containing water vapor is supplied to the heat storage material to release heat. To the heat storage material Hand and a second introduction portion for supplying the

[0007] A second aspect of the present invention is the heat storage device of the first aspect, wherein the heat storage material contains at least one selected from the group consisting of magnesium and calcium.

[0008] A third aspect of the present invention is a heat utilization system comprising: a heat storage device according to the first or second aspect; a low-temperature gas supply unit that causes heat to be released from the heat storage material by supplying a low-temperature gas containing water vapor to the first inlet and the second inlet; and a control unit that controls the low-temperature gas supply unit to reduce the amount of the low-temperature gas supplied to the first inlet or to stop the supply and to start the supply of the low-temperature gas to the second inlet when a predetermined condition is satisfied after the start of the supply of the low-temperature gas to the first inlet.

[0009] A fourth aspect of the present invention is a heat utilization system according to the third aspect, further comprising a high-temperature gas supply section which supplies high-temperature gas to the first inlet section to store heat in the heat storage material, the first inlet section being located below or below the heat storage material, and when the high-temperature gas is supplied from the high-temperature gas supply section to the first inlet section, the heat storage material flows under the force of the high-temperature gas ejected from the first inlet section.

[0010] A fifth aspect of the present invention is a heat utilization system according to the fourth aspect, wherein the heat storage device further comprises a pressure member above the heat storage material, and the position of the pressure member when the high-temperature gas is supplied from the high-temperature gas supply section to the heat storage device is higher than the position of the pressure member when the low-temperature gas is supplied from the low-temperature gas supply section to the heat storage device.

[0011] A sixth aspect of the present invention is the heat utilization system of the fourth aspect (which may be the fourth or fifth aspect), in which the high-temperature gas supply unit is provided in a waste incineration facility or a power plant.

[0012] A seventh aspect of the present invention is the heat utilization system of aspect 4 (which may be any one of aspects 4 to 6), wherein the high-temperature gas supply section supplies the high-temperature gas generated by utilizing combustion in a combustion equipment to the first inlet section, and the heat utilization system further includes an exhaust passage that guides the gas discharged from the exhaust port to an exhaust gas treatment device of the combustion equipment.

[0013] An eighth aspect of the present invention is the heat utilization system of the fourth aspect (which may be any one of the fourth to seventh aspects), wherein the heat storage device is transportable. Effect of the Invention

[0014] According to the present invention, heat can be efficiently extracted from a granular heat storage material containing an alkaline earth metal. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a diagram showing a heat utilization system on the heat storage side. [Diagram 2] FIG. 1 is a diagram showing a heat utilization system on the heat dissipation side. [Diagram 3] FIG. 2 is a diagram showing the structure of a heat storage device. [Figure 4A] FIG. 2 is a diagram showing the structure of a heat storage device. [Figure 4B] FIG. 2 is a diagram showing the structure of a heat storage device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] FIG. 1 is a diagram showing a heat utilization system 1a on the heat storage side. FIG. 2 is a diagram showing a heat utilization system 1b on the heat dissipation side. The heat utilization systems 1a and 1b include a heat storage device 10, and the heat storage device 10 can be separated from the heat utilization systems 1a and 1b. In the following description, separation of the heat storage device 10 from the parts of the heat utilization systems 1a and 1b other than the heat storage device 10 is simply expressed as separation of the heat storage device 10 from the heat utilization systems 1a and 1b. Similarly, connection of the heat storage device 10 to the parts of the heat utilization systems 1a and 1b other than the heat storage device 10 is simply expressed as connection of the heat storage device 10 to the heat utilization systems 1a and 1b.

[0017] The heat storage device 10 stores and releases heat through chemical reactions of the heat storage material. In the heat utilization system 1a, heat is stored in the heat storage device 10. "Storing heat" means "heat storage" and refers to accumulating thermal energy. In the heat utilization system 1b, heat is released from the heat storage device 10. "Releasing heat" means "heat dissipation" and refers to releasing thermal energy.

[0018] When heat is stored in the heat storage device 10 in the heat utilization system 1a, the heat storage device 10 is separated from the main body of the heat utilization system 1a and transported to the heat utilization system 1b in which the heat storage device 10 is not present. The heat storage device 10 is connected to the heat utilization system 1b, and heat is released from the heat storage device 10, and the heat is utilized in the heat utilization system 1b. The heat storage device 10 that has stored heat in the heat utilization system 1a may be stored in a predetermined location before being connected to the heat utilization system 1b. In addition, the heat utilization system 1a and the heat utilization system 1b may be regarded as a single heat utilization system.

[0019] 1, the heat utilization system 1a includes a heat storage device 10, a high-temperature gas supply unit 11, and a discharge path 121. The high-temperature gas supply unit 11 includes a supply path 111, a valve 112, a heat exchanger 113, an auxiliary path 114, and a valve 115. In this embodiment, the heat exchanger 113 is provided in a waste incineration facility 9. The heat exchanger 113 may be a part of the waste incineration facility 9.

[0020] The supply path 111 is connected to the lower connection part 101 of the heat storage device 10. The lower connection part 101 is provided at the bottom of the heat storage device 10. The valve 112 is provided on the supply path 111. External air or air present in the waste incineration facility 9 is introduced into the heat exchanger 113, and the air is heated using high-temperature gas from the incinerator 91 to generate high-temperature dry air (hereinafter referred to as "high-temperature gas"). When the valve 112 is opened, the high-temperature gas is supplied to the inside of the heat storage device 10 via the lower connection part 101.

[0021] The discharge path 121 is connected to the upper connection part 103 of the heat storage device 10. The upper connection part 103 is provided at the top of the heat storage device 10. A valve 122 is provided on the discharge path 121. When high-temperature gas is supplied to the heat storage device 10 from the lower connection part 101, the valve 122 is opened and the gas in the heat storage device 10 is discharged from the upper connection part 103 through the discharge path 121. The discharge path 121 is connected to an exhaust gas treatment device 92 of the waste incineration facility 9, and the gas from the heat storage device 10 is supplied to the exhaust gas treatment device 92.

[0022] The auxiliary passage 114 connects the supply passage 111 and the discharge passage 121. One end of the auxiliary passage 114 is connected to the supply passage 111 between the valve 112 and the heat exchanger 113. The other end of the auxiliary passage 114 is connected to the discharge passage 121 between the valve 122 and the exhaust gas treatment device 92. The valve 115 is provided on the auxiliary passage 114. While the heat storage device 10 is connected to the heat utilization system 1a, the valve 115 is closed. When the heat storage device 10 is separated from the heat utilization system 1a, the valve 115 is opened, the valves 112 and 122 are closed, and the high-temperature gas flows directly from the supply passage 111 to the discharge passage 121. This prevents the temperature of the heat exchanger 113 from increasing.

[0023] As shown in Fig. 2, the heat utilization system 1b on the heat dissipation side includes a heat storage device 10, a low-temperature gas supply unit 13, a control unit 14, and a heat acquisition unit 15. The low-temperature gas supply unit 13 includes a supply path 131, valves 132a and 132b, a blower 133, a preheater 134, and a humidifier 135. The supply path 131 branches into two paths and is connected to the lower connection part 101 and the intermediate connection part 102 of the heat storage device 10, respectively. The intermediate connection part 102 is provided between the lower connection part 101 and the upper connection part 103 of the heat storage device 10. The valve 132a is provided on the supply path 131 connected to the lower connection part 101. The valve 132b is provided on the supply path 131 connected to the intermediate connection part 102.

[0024] Air from the blower 133 is sent to the preheater 134. The preheater 134 heats the air as necessary. The air heated by the preheater 134 is sent to the humidifier 135. The humidifier 135 adds water vapor to the air. When the valve 132a is opened, the gas from the humidifier 135 is supplied to the inside of the heat storage device 10 via the lower connection part 101. When the valve 132b is opened, the gas from the humidifier 135 is supplied to the inside of the heat storage device 10 via the intermediate connection part 102. Since the temperature of the gas from the humidifier 135 is lower than the temperature of the high-temperature gas of the heat utilization system 1a in FIG. 1, hereinafter, the gas containing water vapor from the humidifier 135 is referred to as "low-temperature gas."

[0025] The heat acquisition unit 15 includes a discharge path 151, a valve 152, and a heat exchanger 153. The discharge path 151 is connected to the upper connection part 103 of the heat storage device 10. The valve 152 is provided on the discharge path 151. When low-temperature gas is supplied to the heat storage device 10 from the lower connection part 101 and / or the intermediate connection part 102, the valve 152 is opened, and the gas in the heat storage device 10 is discharged from the upper connection part 103 through the discharge path 151. The heat exchanger 153 is provided on the discharge path 151, and heats the heat medium using the heat of the gas in the discharge path 151. The heat of the heat medium is used in the heat utilization facility 8. The heat utilization facility 8 is, for example, a heating facility or a hot water supply facility. The heat exchanger 153 may be a part of the heat utilization facility 8. The gas in the discharge path 151 from which heat has been removed by the heat exchanger 153 returns to the blower 133. In the heat utilization system 1b, gas circulates.

[0026] FIG. 3 is a diagram showing the structure of the heat storage device 10. In FIG. 3, a vertical cross section of the internal structure of the heat storage device 10 is shown in a simplified form (similarly in FIG. 4A and FIG. 4B). The heat storage device 10 includes a container body 21, a heat storage material 22, a first introduction part 23, a second introduction part 24, an outlet 25, a pressing member 26, three thermometers 27, 28, 29, a lower connection part 101, an intermediate connection part 102, and an upper connection part 103. The container body 21 is substantially cylindrical having a bottom part and a top part. The container body 21 stores the heat storage material 22 therein. The heat storage material 22 is granular and contains an alkaline earth metal, and in this embodiment, the alkaline earth metal is magnesium. In a state where heat is released by a hydration reaction, the heat storage material 22 has magnesium hydroxide as a main component, and in a state where heat is stored by a dehydration reaction, the heat storage material 22 has magnesium oxide as a main component. In the following description, unless otherwise specified, the "heat storage material 22" means an aggregate of heat storage material particles.

[0027] The lower connection part 101, the intermediate connection part 102, and the upper connection part 103 are provided on the outer peripheral surface of the container body 21. When the heat storage device 10 is connected to the heat utilization system 1a of FIG. 1, the lower connection part 101 is detachably connected to the supply path 111, and the upper connection part 103 is detachably connected to the discharge path 121. When the heat storage device 10 is connected to the heat utilization system 1b of FIG. 2, the lower connection part 101 is detachably connected to one of the branch paths of the supply path 131, the intermediate connection part 102 is detachably connected to the other of the branch paths of the supply path 131, and the upper connection part 103 is detachably connected to the discharge path 151. FIG. 3 shows a state in which the heat storage device 10 is connected to the heat utilization system 1a.

[0028] The first introduction part 23 is provided in the lower part of the container body 21. That is, it is provided in the lower part of the heat storage material 22 (layer). The first introduction part 23 is connected to the lower connection part 101. The first introduction part 23 has a plurality of ejection ports, and when gas is supplied to the first introduction part 23 via the lower connection part 101, the gas is ejected upward from the ejection ports toward the heat storage material 22. As a result, gas is supplied from the first introduction part 23 toward the heat storage material 22. The ejection ports are arranged two-dimensionally in the horizontal direction at the lower part of the container body 21. For example, the first introduction part 23 has a plurality of tubes arranged in the horizontal direction at the lower part of the container body 21, and a plurality of ejection ports are provided in these tubes.

[0029] The second introduction part 24 is provided between the first introduction part 23 and the exhaust port 25. To be precise, the second introduction part 24 is provided at a position between the first introduction part 23 and the exhaust port 25 in the height direction. The second introduction part 24 is connected to the intermediate connection part 102. Like the first introduction part 23, the second introduction part 24 also has a plurality of outlets and supplies gas toward the heat storage material 22. The plurality of outlets are arranged two-dimensionally in the horizontal direction. In the state of FIG. 3, no pipe is connected to the intermediate connection part 102, but when gas is supplied to the second introduction part 24 through the intermediate connection part 102, the gas is ejected upward from the outlet toward the heat storage material 22.

[0030] The pressing member 26 is a mesh-like plate. The pressing member 26 may be a plate in which many small holes are formed. The pressing member 26 is located above the heat storage material 22, and can be located at either of two positions, a lower position or an upper position. In FIG. 3, the lower position is indicated by an imaginary two-dot chain line, and the pressing member 26 located at the upper position is indicated by a thick dashed line. The lower position is close to the upper surface of the heat storage material 22 in a stationary state (see FIG. 4A). The upper position is located at the top of the container body 21, and is located above the discharge port 25 in the height direction. The pressing member 26 may be moved up and down manually or automatically. As shown in FIG. 3, during heat storage, that is, when high-temperature gas is supplied from the high-temperature gas supply unit 11 in FIG. 1 to the heat storage device 10 to cause the heat storage material 22 to flow, the pressing member 26 is located at the upper position.

[0031] As already explained, during heat storage, the supply path 111 is connected to the lower connection part 101. By opening the valve 112 and the valve 122, high-temperature gas is supplied from the high-temperature gas supply part 11 to the first introduction part 23. The high-temperature gas is dry, high-temperature air. Since the first introduction part 23 is located below the heat storage material 22, when the high-temperature gas is ejected upward from the first introduction part 23 toward the heat storage material 22, the particles of the heat storage material 22 flow in the container body 21 under the pressing member 26 located at the upper position due to the force from the high-temperature gas. The flow of the heat storage material 22 occurs between the bottom of the container body 21 and the discharge port 25 in the height direction. Note that, since the flow of the heat storage material 22 generates fine particles of the heat storage material 22 (hereinafter referred to as "heat storage material fine particles") in the container body 21, in order to suppress adhesion of the heat storage material fine particles to the pressing member 26, it is preferable that the upper position is higher than the discharge port 25 in the height direction.

[0032] Before heat storage, the main component of the heat storage material 22 in the heat storage device 10 is magnesium hydroxide. When the heat storage material 22 is exposed to high-temperature gas, water is removed from the magnesium hydroxide of the heat storage material 22 through the following dehydration reaction: Mg(OH) 2 +Dehydration heat → MgO+H 2 O The main component of the heat storage material 22 changes to magnesium oxide. As a result, the residual heat that was conventionally wasted in the waste incineration facility 9 is stored in the heat storage material 22.

[0033] As described later, there is a risk that the granular heat storage material 22 will adhere to one another and become lumps of a certain size when heat is released due to a hydration reaction, but by flowing the heat storage material 22 during heat storage, the heat storage material 22 returns to a separate granular state. As a result, the degree of adhesion during the next heat release can be reduced, improving the stability of heat release and the lifespan of the heat storage material 22. Note that high-temperature gas may be ejected from the first introduction part 23 and the second introduction part 24 during heat storage. This allows heat to be stored in the heat storage material 22 more efficiently.

[0034] Since the second introduction part 24 exists in the container body 21, when high-temperature gas is supplied from the first introduction part 23 to cause the heat storage material 22 to flow, the second introduction part 24 acts as an obstacle to promote separation of the adhered heat storage material 22. In addition, the flow rate increases when the gas passes through the tubes of the second introduction part 24, which also promotes separation of the adhered heat storage material 22.

[0035] The high-temperature gas is discharged from inside the container body 21 through the exhaust port 25. The gas discharged from the exhaust port 25 is further guided to the exhaust path 121 through the upper connection part 103. As shown in FIG. 1, the high-temperature gas used for heat storage (hereinafter referred to as "used gas") is guided from the exhaust path 121 to the exhaust gas treatment device 92 of the waste incineration facility 9. As described above, the flow of the heat storage material 22 during heat storage generates fine heat storage material particles in the container body 21, but the heat storage device 10 is not provided with a device for removing the fine heat storage material particles, and the used gas contains the fine heat storage material particles. Therefore, the fine heat storage material particles are guided to the exhaust gas treatment device 92 through the exhaust path 121 together with the used gas.

[0036] In the exhaust gas treatment device 92, the used gas from the heat storage device 10 is added to the waste incineration exhaust gas (hereinafter referred to as "combustion exhaust gas"), and the heat storage material fine particles, i.e., magnesium hydroxide and magnesium oxide fine particles, are used to neutralize acid gases (hydrogen chloride (HCl), sulfur oxides (SOx), etc.) in the combustion exhaust gas. The heat storage material fine particles may be simply mixed with the combustion exhaust gas immediately before the bag filter, for example, or may be used as an alkaline agent in a wet neutralization device. As described above, in the heat utilization system 1a, it is possible to effectively utilize the fine particles generated from the heat storage material 22. In addition, it is possible to prevent the heat storage material fine particles from diffusing into the atmosphere.

[0037] When the supply of high-temperature gas to the heat storage device 10 has been performed for a certain period of time, or when the temperature of the used gas obtained by the thermometer 27 provided near the discharge port 25 has risen to a predetermined temperature, heat storage is deemed to be completed, and the valve 115 is opened and the valves 112 and 122 are closed to stop the supply of high-temperature gas to the heat storage device 10. The high-temperature gas is guided from the supply path 111 through the auxiliary path 114 to the discharge path 121. In addition, the lower connection part 101 is separated from the supply path 111, and the upper connection part 103 is separated from the discharge path 121. The thermometer 27 may be provided in the discharge path 121.

[0038] 4A and 4B are diagrams showing the heat storage device 10 during heat dissipation. As already described, when the heat storage device 10 is connected to the heat utilization system 1b of FIG. 2, the lower connection part 101, the intermediate connection part 102, and the upper connection part 103 are separably connected to one and the other of the branch paths of the supply path 131 and the discharge path 151, respectively. When low-temperature gas is supplied from the low-temperature gas supply part 13 to the heat storage device 10, the pressing member 26 is located at the lower position. The thermometer 28 is located in the heat storage material 22 between the first introduction part 23 and the second introduction part 24 in the height direction. Preferably, the thermometer 28 is located between the second introduction part 24 and a position that divides the distance between the first introduction part 23 and the second introduction part 24 in the height direction. The thermometer 29 is located in the heat storage material 22 between the second introduction part 24 and the upper surface of the heat storage material 22 in the height direction. Preferably, the thermometer 29 is located between a position that divides the space between the second introduction portion 24 and the upper surface of the heat storage material 22 in half in the height direction and the upper surface of the heat storage material 22.

[0039] During heat dissipation, first, valves 132a and 152 are opened under the control of low-temperature gas supply unit 13 by control unit 14, and low-temperature gas containing water vapor is supplied to first introduction unit 23 as shown in Fig. 4A. At this time, valve 132b remains closed, and low-temperature gas is not supplied from second introduction unit 24. When low-temperature gas is ejected upward from first introduction unit 23 toward heat storage material 22, the magnesium oxide of heat storage material 22 reacts with water vapor in the following hydration reaction, MgO+H 2 O → Mg(OH) 2 +Reaction heat Magnesium oxide changes to magnesium hydroxide, generating heat. As a result, the low-temperature gas is heated and guided from the discharge port 25 to the discharge path 151 via the upper connection part 103. Since the pressing member 26 is located at the lower position, the heat storage material 22 does not flow. The heat storage material 22 exists as a fixed layer in the heat storage device 10. In the following description, the gas that is heated and discharged from the discharge port 25 is called "heated gas." The temperature of the heated gas at the position of the discharge port 25 is preferably 170°C or higher and 220°C or lower.

[0040] As shown in FIG. 2, the heated gas is guided from the exhaust passage 151 to the heat exchanger 153. In the heat exchanger 153, the heat of the heated gas is transferred to the heat medium, and the heat of the heat medium is utilized by the heat utilization equipment 8. As a result, the residual heat generated in the waste incineration facility 9 in FIG. 1 is utilized by the heat utilization equipment 8. When the heat of the heated gas is removed in the heat exchanger 153, the heated gas is heated by the preheater 134 via the blower 133 as necessary, and is humidified by the humidifier 135 to become a low-temperature gas containing a large amount of water vapor. Then, the low-temperature gas is guided to the first introduction part 23 via the valve 132a and the lower connection part 101. The amount of the low-temperature gas supplied per unit time to the heat storage device 10 is less than the amount of the high-temperature gas supplied per unit time to the heat storage device 10 during heat storage, for example, is less than half.

[0041] After a predetermined time has elapsed since the supply of low-temperature gas from the first introduction part 23 was started, or when the temperature of the thermometer 28 provided in the heat storage material 22 at the lower part of the heat storage device 10 has passed its peak, the control part 14 controls the valve 132a of the low-temperature gas supply part 13 to reduce the supply amount of low-temperature gas to the first introduction part 23 (more precisely, the supply amount per unit time). On the other hand, the control part 14 controls the valve 132b of the low-temperature gas supply part 13 to start supplying low-temperature gas to the second introduction part 24, as shown in FIG. 4B. Instead of reducing the supply amount of low-temperature gas to the first introduction part 23, the supply of low-temperature gas to the first introduction part 23 may be stopped. The supply amount of low-temperature gas to the first introduction part 23 may be gradually reduced. The total supply amount of low-temperature gas to the first introduction part 23 and the second introduction part 24 may be constant or may not be constant.

[0042] When the supply of low-temperature gas from the second introduction part 24 to the heat storage device 10 has been performed for a certain period of time, or when the temperature acquired by the thermometer 29 has passed its peak (or further when the temperature of the heated gas acquired by the thermometer 27 provided near the discharge port 25 has passed its peak), it is determined that the heat dissipation of the entire heat storage material 22 has been completed, and the control part 14 closes the valves 132a, 132b, 152, and the supply of low-temperature gas to the heat storage device 10 is stopped. In addition, the lower connection part 101 and the intermediate connection part 102 are separated from the supply path 131, and the upper connection part 103 is separated from the discharge path 151. The thermometer 27 may be provided in the discharge path 151.

[0043] In the above control during heat dissipation, first, low-temperature gas is supplied to the heat storage material 22 only from the first introduction part 23. Since the low-temperature gas from the first introduction part 23 rises while being heated by the heat dissipation from the heat storage material 22, the gas becomes hot at the upper part of the heat storage material 22 and the heat dissipation reaction does not occur much. In addition, the reaction ends early near the first introduction part 23, and the heat storage material 22 absorbs excessive water vapor due to continued exposure to water vapor thereafter, and the particles become stuck together. The space between the heat storage material 22 narrows, and the resistance to ejecting the low-temperature gas from the first introduction part 23 increases. As a result, the low-temperature gas cannot be ejected efficiently from the first introduction part 23.

[0044] On the other hand, after a certain amount of time has elapsed since the supply of low-temperature gas to the first introduction section 23 was started and the heat dissipation reaction in the lower part of the heat storage material 22 has ended, the supply of low-temperature gas to the first introduction section 23 is reduced or stopped, and the supply of low-temperature gas to the second introduction section 24 is started. This makes it possible to efficiently supply low-temperature gas to the heat storage material 22 present above the second introduction section 24, and to stably carry out the reaction of the entire heat storage material 22. As a result, it is possible to efficiently extract heat from the entire granular heat storage material 22, and heat dissipation can be promoted.

[0045] Moreover, by reducing or stopping the supply of low-temperature gas to the first introduction part 23 when supplying low-temperature gas from the second introduction part 24, excessive adhesion of the lower part of the heat storage material 22 can be suppressed. In this way, by using the second introduction part 24, it is possible to suppress a decrease in the reaction rate of the entire heat storage material 22 and inhibition of the reaction process due to pressure loss, which occurs when only the first introduction part 23 is used. Furthermore, by reducing the pressure loss, the output of the blower 133 can be designed to be low, and the operating cost of the heat utilization system 1b can be kept low.

[0046] In the heat utilization systems 1a and 1b, the heat storage device 10 is transportable, so the heat storage device 10 can be stored in any location after heat storage. In addition, because heat is stored using a chemical reaction, there is no heat dissipation over time. As a result, heat storage, transportation, and storage are possible with great efficiency.

[0047] The heat utilization systems 1a and 1b and the heat storage device 10 described above are merely examples and do not limit the present invention.

[0048] Generally speaking, the heat storage material 22 stores heat through a dehydration reaction of an alkaline earth metal hydroxide and releases heat through a hydration reaction of the alkaline earth metal oxide. The alkaline earth metal contained in the heat storage material 22 is not limited to magnesium. Preferably, the heat storage material 22 contains at least one selected from the group consisting of magnesium and calcium. Alkaline earth metals other than magnesium and calcium can also be used.

[0049] The shape of each particle of the heat storage material 22 (hereinafter referred to as "heat storage material particle") is preferably so-called "pellet-like". For example, the heat storage material particle is cylindrical with a diameter of 1 mm to 10 mm and a length of 1 mm to 10 mm. More preferably, the heat storage material particle is cylindrical with a diameter of 1 mm to 5 mm and a length of 1 mm to 5 mm. The heat storage material particle may be spherical with a diameter of 1 mm to 10 mm. Preferably, the heat storage material particle is spherical with a diameter of 1 mm to 5 mm. The shape of the heat storage material particle may be other shapes such as a rectangular parallelepiped.

[0050] The container body 21 that houses the heat storage material 22 refers to a structure that essentially forms a space that houses the heat storage material 22. The container body 21 is not limited to a substantially cylindrical shape as long as it can form a space that houses the heat storage material 22. For example, it may be a substantially rectangular parallelepiped or a barrel shape.

[0051] The first introduction part 23 and the second introduction part 24 may be provided in various forms as long as they are structures that can be used when supplying gas toward the heat storage material 22. The first introduction part 23 preferably has a structure that can forcefully eject gas toward the heat storage material 22 in order to cause the heat storage material 22 to flow. The structure for ejecting gas is not limited to a nozzle, and for example, a porous plate having a large number of small holes may be placed at the bottom of the container body 21, the heat storage material 22 may be deposited on the porous plate, and gas may be introduced below the porous plate to eject gas toward the heat storage material 22. When gas flows upward in the container body 21, the first introduction part 23 is located at least below or at a lower part of the heat storage material 22. "Located below the heat storage material 22" means that it is located below the heat storage material 22. "Located at the lower part of the heat storage material 22" means that it is located so as to be in contact with the inside of the lower part of the heat storage material 22 or the lowest end. The second introduction part 24 does not have to have a structure for forcefully ejecting gas. The first introduction part 23 and the second introduction part 24 preferably have gas outlets arranged two-dimensionally in the horizontal direction.

[0052] The exhaust outlet 25 may be provided in various ways as long as it is an opening that exhausts gas from inside the container body 2. Providing the exhaust outlet 25 in the container body 21 means, more precisely, providing a member that forms the exhaust outlet 25 in the container body 21. The exhaust outlet 25 may be a simple opening provided in the upper portion or upper end of the container body 21, or may be a pipe leading from inside the container body 21 to the outside.

[0053] The second introduction part 24 has a role of assisting the supply of low-temperature gas from the first introduction part 23, and is provided at a position between the first introduction part 23 and the discharge port 25. The first introduction part 23, the second introduction part 24, and the discharge port 25 do not need to be arranged vertically, and may be arranged, for example, horizontally. Furthermore, in the heat storage device 10, the discharge port 25, the second introduction part 24, and the first introduction part 23 may be provided in this order from the bottom. The arrangement order of the first introduction part 23, the second introduction part 24, and the discharge port 25 is based on the flow of gas, and they do not need to be arranged linearly. That is, the second introduction part 24 is provided at a position between the first introduction part 23 and the discharge port 25 with respect to the direction in which gas flows in the container body 21.

[0054] The low-temperature gas is preferably air containing water vapor. The temperature of the low-temperature gas (particularly when the alkaline earth metal contained in the heat storage material 22 is magnesium) is preferably 90°C or higher and 110°C or lower, and the amount of water vapor contained in the low-temperature gas is preferably 50% by volume or higher and 60% by volume or lower. The low-temperature gas may be a gas other than air containing water vapor. Alternatively, it may be air with its components adjusted containing water vapor.

[0055] In the heat utilization system 1b, the control unit 14 controls the low-temperature gas supply unit 13 to start the supply of low-temperature gas to the second introduction unit 24 at a stage after the supply of low-temperature gas to the first introduction unit 23 is started. In the above explanation, the supply of low-temperature gas to the second introduction unit 24 is started a certain time after the supply of low-temperature gas to the first introduction unit 23 is started, or the supply of low-temperature gas to the second introduction unit 24 is started when the temperature of the thermometer 28 at the lower part of the heat storage device 10 passes its peak after the supply of low-temperature gas to the first introduction unit 23 is started.

[0056] Of course, the supply of low-temperature gas to the second introduction part 24 may be started based on other conditions. For example, the supply of low-temperature gas to the second introduction part 24 may be started at a stage where the supply pressure of the gas to the first introduction part 23 exceeds a predetermined value. Generally speaking, the supply of low-temperature gas to the second introduction part 24 is started at a stage where a predetermined condition indicating the completion of the heat dissipation reaction of the heat storage material 22 (or the lower part of the heat storage material 22) in the vicinity of the first introduction part 23 is satisfied. Also, as already described, at the same time (not necessarily completely simultaneously, as long as substantially simultaneously), an operation is performed to reduce the supply amount of low-temperature gas to the first introduction part 23 or to stop the supply of low-temperature gas to the first introduction part 23.

[0057] In addition, two or more introduction parts (hereinafter referred to as "intermediate introduction parts") may be provided between the first introduction part 23 and the discharge port 25. In this case, the second introduction part 24 in the above description corresponds to any one of the intermediate introduction parts. The above-mentioned FIG. 4A and FIG. 4B show a case where the number of intermediate introduction parts is one. When two or more intermediate introduction parts are provided between the first introduction part 23 and the discharge port 25, the supply of low-temperature gas to the multiple intermediate introduction parts is started in order from the intermediate introduction part close to the first introduction part 23 to the intermediate introduction part close to the discharge port 25 each time a plurality of predetermined conditions are sequentially satisfied after the supply of low-temperature gas to the first introduction part 23 is started. As a result, even when a large amount of the heat storage material 22 is stored in the container body 21, it is possible to efficiently extract heat from the heat storage material 22. In addition, in order to appropriately perform the above control, it is preferable to provide a thermometer in each range partitioned in the height direction by the first introduction part 23, the one or more intermediate introduction parts, and the upper surface of the heat storage material 22. Each thermometer is preferably provided between a position which bisects the corresponding range and the upper end of the range.

[0058] 2, gas is circulated while utilizing the heat storage device 10, but gas circulation is not required. For example, the low-temperature gas supply unit 13 may take in external air, generate low-temperature gas containing water vapor, and supply it to the heat storage device 10, and the heated gas from the heat storage device 10 may be discharged into the atmosphere after heat is removed by the heat exchanger 153. Also, the heat exchanger 153 may be omitted, and the heated gas may be directly utilized in the heat utilization facility 8.

[0059] The temperature of the high-temperature gas during heat storage is preferably 300°C or higher and 400°C or lower (particularly when the alkaline earth metal contained in the heat storage material 22 is magnesium). The high-temperature gas may be a gas other than air. Alternatively, the high-temperature gas may be air with its components adjusted. In the above explanation, during heat storage, the high-temperature gas is supplied from the high-temperature gas supply section 11 to the first introduction section 23, and the heat storage material 22 flows due to the force of the high-temperature gas ejected from the first introduction section 23; however, in the case of a heat storage material 22 that does not have the problem of sticking during heat release, the heat storage material 22 does not need to flow during heat storage.

[0060] The pressing member 26 of the heat storage device 10 may have a structure other than a mesh plate or a perforated plate as long as it is disposed above the heat storage material 22 and can prevent the heat storage material 22 from scattering. The pressing member 26 can be expressed functionally as a scattering prevention member. The pressing member 26 may be, for example, a member having a large number of slits.

[0061] In the heat utilization system 1a, surplus heat from a power plant may be stored in the heat storage device 10 instead of the waste incineration facility 9. More generally, in the heat utilization system 1a, it is preferable that high-temperature gas is generated by utilizing combustion in a combustion facility such as an industrial furnace and supplied to the first inlet part 23. More preferably, the used gas discharged from the exhaust port 25 is led via the exhaust path 151 to an exhaust gas treatment device of the combustion facility, whereby the fine heat storage material particles are used as an alkaline agent in the exhaust gas treatment device.

[0062] 1 does not need to be provided as a dedicated structure for the combustion equipment. The high-temperature gas supply unit 11 may be a structure that utilizes a structure already provided in the combustion equipment to supply dry high-temperature gas to the heat storage device 10. In this case, the high-temperature gas supply unit 11 is mainly composed of a supply path 111 and a valve 112.

[0063] It is preferable that the heat utilization system 1a and the heat utilization system 1b are combined, but a heat storage method of the heat utilization system 1a may be adopted while a heat dissipation method different from that of the heat utilization system 1b may be adopted. Also, a heat storage method different from that of the heat utilization system 1a may be adopted while a heat dissipation method of the heat utilization system 1b may be adopted. The heat storage device 10 is preferably transported between the heat utilization system on the heat storage side and the heat utilization system on the heat dissipation side, but heat storage and dissipation may be performed with the heat storage device 10 in a fixed installation state.

[0064] The configurations in the above-described embodiment and each of the modified examples may be combined as appropriate as long as they are not mutually inconsistent. [Explanation of symbols]

[0065] 1a, 1b Heat utilization system 9. Waste incineration facilities 10 Heat storage device 11 Hot gas supply section 13 Low temperature gas supply section 14 Control section 21 Container body 22 Heat storage material 23 Part 1 Introduction 24 Second introduction 25 Outlet 26 Holding member 27~29 Thermometer 92 Exhaust gas treatment equipment 121 Exhaust channel

Claims

1. A heat storage device that stores and releases heat, A container body that contains a granular heat storage material containing an alkaline earth metal; A first introduction section for supplying a low-temperature gas containing water vapor toward the heat storage material in order to release heat from the heat storage material; an exhaust port for exhausting gas from within the container body; a second inlet for supplying a low-temperature gas containing water vapor toward the heat storage material at a position between the first inlet and the outlet in order to release heat from the heat storage material; A heat storage device comprising:

2. The heat storage device according to claim 1, The heat storage device, wherein the heat storage material contains at least one selected from the group consisting of magnesium and calcium.

3. A heat utilization system, The heat storage device according to claim 1 or 2; a low-temperature gas supply unit that supplies a low-temperature gas containing water vapor to the first introduction unit and the second introduction unit to release heat from the heat storage material; a control unit that controls the low-temperature gas supply unit to reduce or stop the supply of the low-temperature gas to the first introduction unit and start the supply of the low-temperature gas to the second introduction unit when a predetermined condition is satisfied after the start of the supply of the low-temperature gas to the first introduction unit; A heat utilization system comprising:

4. The heat utilization system according to claim 3, A high-temperature gas supply unit that supplies high-temperature gas to the first introduction unit to store heat in the heat storage material, The first introduction part is located below or at a lower part of the heat storage material, A heat utilization system in which, when the high-temperature gas is supplied from the high-temperature gas supply unit to the first inlet, the heat storage material flows due to a force exerted by the high-temperature gas ejected from the first inlet.

5. The heat utilization system according to claim 4, The heat storage device further includes a pressing member above the heat storage material, A heat utilization system in which the position of the pressing member when the high-temperature gas is supplied from the high-temperature gas supply section to the heat storage device is higher than the position of the pressing member when the low-temperature gas is supplied from the low-temperature gas supply section to the heat storage device.

6. The heat utilization system according to claim 4, The heat utilization system, wherein the high-temperature gas supply unit is provided in a waste incineration facility or a power plant.

7. The heat utilization system according to claim 4, The high-temperature gas supply unit supplies the high-temperature gas generated by utilizing combustion in a combustion facility to the first introduction unit, The heat utilization system further includes an exhaust passage for guiding the gas exhausted from the exhaust port to an exhaust gas treatment device of the combustion facility.

8. The heat utilization system according to claim 4, The heat utilization system, wherein the heat storage device is transportable.

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