Chemical heat storage block, chemical heat storage device, and method for chemical heat storage and heat dissipation

Abstract

To provide a chemical heat storage block that can perform efficient chemical heat storage.SOLUTION: A chemical heat storage block 110 includes: a porous substrate 111 having a communication air hole; and a chemical heat storage medium filled into the communication air hole of the porous substrate 111, where the chemical heat storage medium generates heat when reacting with a reaction medium and absorbs heat when being separated from the reaction medium and the porous substrate 111 has a through-flow channel 112 for circulating vapor of the reaction medium.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a hybrid heat storage system, a chemical heat storage block, a chemical heat storage device using this chemical heat storage block, and a chemical heat storage and heat release method using this chemical heat storage device. [Background technology]

[0002] A variety of thermal storage devices are used as energy storage means.

[0003] Known examples of such heat storage devices include chemical heat storage devices and sensible heat storage devices.

[0004] Chemical heat storage devices can store high-temperature thermal energy, and by adjusting the reaction pressure, they can operate as a chemical heat pump, raising the temperature of the generated heat above that of the stored heat. Higher temperatures in stored heat have higher energy quality (exergy) and thermodynamic value, making chemical heat storage devices preferable from these perspectives. On the other hand, chemical heat storage devices have the problem of being expensive due to their complex configuration.

[0005] Sensible heat storage devices are inexpensive due to their simple structure, but they have the problem of difficulty in storing and retaining high-temperature thermal energy due to the heat resistance and insulation of the container. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention provides a hybrid heat storage system that solves the problems of conventional chemical heat storage devices and sensible heat storage devices as described above. The present invention also provides a chemical heat storage block that can be used in a chemical heat storage device to perform efficient chemical heat storage, and that can be used in the hybrid heat storage system of the present invention. The present invention also relates to a chemical heat storage device that uses this chemical heat storage block, and a chemical heat storage and heat release method that uses this chemical heat storage device. [Means for solving the problem]

[0007] The present invention can be embodied in the following manner.

[0008] <Aspect 1> A hybrid heat storage system having a chemical heat storage device and a sensible heat storage device, In the heat storage stage, the heat medium of the sensible heat storage device is heated by a heat source to obtain the heated heat medium, and the chemical heat storage medium of the chemical heat storage device is heated by at least a part of the heated heat medium to cause an endothermic reaction, and the reaction medium is separated and removed from the chemical heat storage medium to generate the chemical heat storage medium from which the reaction medium has been removed and vapor of the reaction medium at a first pressure, and the heat medium that has been heated to a low temperature by heating the chemical heat storage medium is stored in the sensible heat storage device, In the heat dissipation step, vapor of the reaction medium at a second pressure is supplied to the chemical heat storage medium of the chemical heat storage device to cause an exothermic reaction with the chemical heat storage medium, and at least a portion of the heat medium stored in the sensible heat storage device is reheated by the heated chemical heat storage medium to obtain the reheated heat medium; the second pressure is higher than the first pressure; and The temperature of the heat medium reheated by the chemical heat storage medium in the heat dissipation step is higher than the temperature of the heat medium heated by the heat source in the heat storage step. Hybrid thermal storage system. <Aspect 2> a steam turbine; and supplying the reaction medium steam at the first pressure produced in the heat storage step to the steam turbine to generate electricity; 2. The system of embodiment 1. <Aspect 3> further comprising a heat exchanger; and In the heat storage step, at least a portion of the heat medium whose temperature has been reduced by heating the chemical heat storage medium of the chemical heat storage device is reheated by heat exchange with the heat medium from the heat source in the heat exchanger to obtain the reheated heat medium, and the reheated heat medium is stored in the sensible heat storage device. 3. The system according to claim 1 or 2. <Aspect 4> Aspect 4. The system of any one of aspects 1 to 3, wherein the sensible heat storage device is a thermocline heat storage device. <Aspect 5> Aspect 5. The system of any one of aspects 1 to 4, wherein the chemical heat storage medium is calcium hydroxide and the reaction medium is water. <Aspect 6> A porous substrate having interconnected pores and a chemical heat storage medium filled in the interconnected pores of the porous substrate, The chemical heat storage medium generates heat when reacting with a reaction medium and absorbs heat when separated from the reaction medium; and The porous substrate has through-flow passages for the flow of the reaction medium vapor. Chemical heat storage block. <Aspect 7> A double-pipe container having an inner flow path and an outer flow path, and One or more chemical heat storage blocks according to aspect 6, which are arranged in the inner flow path. and A heat transfer medium is circulated through the outer flow path; In the inner flow path, vapor of the reaction medium is circulated through the through flow path of the chemical heat storage block and between the inner wall of the inner flow path and the chemical heat storage block. Chemical heat storage device. <Aspect 8> Aspect 8. The chemical heat storage device of aspect 7, wherein a plurality of the inner flow channels are disposed within one of the outer flow channels. <Aspect 9> A chemical heat storage and heat release method using the chemical heat storage device according to aspect 7 or 8, In the heat storage stage, the heat medium is circulated through the outer flow path, thereby heating the chemical heat storage medium in the chemical heat storage block and removing the reaction medium, thereby generating the chemical heat storage block from which the reaction medium has been removed and vapor of the reaction medium at a first pressure; In the heat dissipation step, the heat medium is circulated through the outer flow path, and the vapor of the reaction medium at a second pressure is circulated through the inner flow path to cause the chemical heat storage block to generate heat, and the heat medium supplied to the outer flow path is reheated by the generated heat chemical heat storage block to obtain the heated heat medium; the second pressure is higher than the first pressure; and The temperature of the heat medium reheated by the chemical heat storage medium in the heat dissipation step is higher than the temperature of the heat medium that heats the chemical heat storage medium in the heat storage step. Chemical heat storage and release methods. [Effects of the Invention]

[0009] According to the hybrid heat storage system of the present invention, it is possible to solve the problems of conventional chemical heat storage devices and sensible heat storage devices. Furthermore, the chemical heat storage block of the present invention can be used in a chemical heat storage device to perform efficient chemical heat storage, and can be used in particular in the hybrid heat storage system of the present invention. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing (a) the heat storage stage and (b) the heat release stage of a first embodiment of the hybrid heat storage system of the present invention. [Figure 2] FIG. 2 is a diagram showing (a) the heat storage stage and (b) the heat release stage of a second embodiment of the hybrid heat storage system of the present invention. [Figure 3] FIG. 3 shows (a) a perspective view, (b) a side cross-sectional view, and (c) a top view showing a first embodiment of the chemical heat storage block of the present invention. [Figure 4] FIG. 4 shows a second embodiment of the chemical heat storage block of the present invention, with (a) a perspective view, (b) a side cross-sectional view, and (c) a top view. [Figure 5] FIG. 5 is a photograph showing a silicon carbide-based porous substrate (left photo) and a chemical heat storage block of the present invention (right photo) manufactured using this silicon carbide-based porous substrate. [Figure 6] FIG. 6 shows (a) a perspective view, (b) a side cross-sectional view, and (c) a top view of a first embodiment of the chemical heat storage device of the present invention. [Figure 7] FIG. 7 shows a second embodiment of the chemical heat storage device of the present invention, with (a) a perspective view, (b) a side cross-sectional view, and (c) a top view. [Figure 8] FIG. 8 is a top view showing (a) a third embodiment, (b) a fourth embodiment, (c) a fifth embodiment, (c) a sixth embodiment, and (c) a seventh embodiment of the chemical heat storage device of the present invention. [Figure 9] FIG. 9 is a diagram for explaining (a) the heat storage stage and (b) the heat release stage of the chemical heat storage and heat release method of the present invention. [Figure 10] FIG. 10 is a diagram showing the relationship between the pressure and temperature of the inner flow path in the heat release stage of the chemical heat storage and heat release method using the chemical heat storage block of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described below based on specific embodiments with reference to the drawings, but the present invention is not limited to these embodiments. The drawings are for illustrative purposes only and do not represent actual dimensional ratios.

[0012] <Hybrid heat storage system> In the following, the hybrid heat storage system of the present invention will be particularly described based on an embodiment in which calcium hydroxide (or calcium oxide) and water are used as the chemical heat storage medium and reaction medium of the chemical heat storage device, respectively, and a thermocline heat storage device is used as the sensible heat storage device. However, it goes without saying that other combinations of chemical heat storage medium and reaction medium, and other sensible heat storage devices can also be used in the hybrid heat storage system of the present invention.

[0013] <First aspect> A first embodiment of the hybrid heat storage system of the present invention has a chemical heat storage device and a sensible heat storage device, as shown with reference to Fig. 1. The temperatures shown in Fig. 1 are examples of temperatures when the hybrid heat storage system of the present invention is operated, and do not necessarily represent actual temperatures.

[0014] (heat storage stage) In the heat storage stage of this hybrid heat storage system, as shown in FIG. 1( a), a heat source (30) heats a heat medium in a sensible heat storage device (20) to obtain a heated heat medium. At least a portion of the heated heat medium is supplied to a chemical heat storage device (10) via a branch valve (91), thereby heating the chemical heat storage medium (Ca(OH)2) in the chemical heat storage device (10) to cause an endothermic reaction. This endothermic reaction separates and removes water (HO) as a reaction medium from the chemical heat storage medium (Ca(OH)2), thereby generating the chemical heat storage medium (CaO) from which the reaction medium (HO) has been removed and steam (HO) of the reaction medium at a first pressure. In addition, the heat medium, which has been heated to a low temperature by heating the chemical heat storage medium (Ca(OH)2), is stored in the sensible heat storage device (20). The reaction medium vapor (HO) at the first pressure can be optionally cooled by heat exchange with cooling water and stored as a liquid in the reaction medium reservoir (50). In this case, the heat medium discharged from the low-temperature side of the sensible heat storage device (20) can be supplied to the heat source (30) via the branch valve (92) and thereby heated by the heat source (30).

[0015] In Fig. 1(a), the dotted lines indicate flow paths that are not used in the heat storage stage. However, although not shown in Fig. 1(a), the heat from the heat source (30) can of course be used not only for heat storage but also for heat utilization equipment (40), such as a power generation equipment.

[0016] (heat dissipation stage) 1(b), in the heat release stage of this hybrid heat storage system, vapor of a reaction medium (HO) at a second pressure is supplied to the chemical heat storage medium (CaO) of the chemical heat storage device (10) to cause an exothermic reaction with the chemical heat storage medium (CaO). Also, the chemical heat storage medium (CaO) thus generated generates heat, which reheats at least a portion of the heat medium stored in the sensible heat storage device (20), thereby obtaining a reheated heat medium.

[0017] Here, the second pressure, i.e., the pressure when vapor of the reaction medium (H2O) is supplied to the chemical heat storage medium (CaO) of the chemical heat storage device (10) in the heat release stage, is higher than the first pressure, i.e., the pressure when the reaction medium (H2O) is separated and removed from the chemical heat storage medium (Ca(OH)2) of the chemical heat storage device (10) in the heat storage stage. Specifically, the second pressure may be 1.1 times or more, 1.3 times or more, 1.5 times or more, 2.0 times or more, 3.0 times or more, 4.0 times or more, or 5.0 times or more of the first pressure, and may be 20.0 times or less, 10.0 times or less, 8.0 times or less, 6.0 times or less, or 5.0 times or less.

[0018] In this way, by making the second pressure higher than the first pressure, the temperature of the heat medium reheated by the chemical heat storage medium in the heat release step can be made higher than the temperature of the heat medium heated by the heat source in the heat storage step. Specifically, this temperature difference may be 1°C or more, 3°C or more, 5°C or more, or 10°C or more, and may be 200°C or less, 150°C or less, 100°C or less, 50°C or less, 30°C or less, 20°C or less, or 10°C or less.

[0019] This is because, in a reaction in which a reactive medium is separated and removed from a chemical heat storage medium by an endothermic reaction, and a chemical heat storage medium from which the reactive medium has been removed and vapor of the reactive medium are generated, for example, in the decomposition reaction of calcium hydroxide shown below, when the reaction pressure increases, the equilibrium shifts to the left side (exothermic reaction side), and when the reaction temperature increases, the equilibrium shifts to the right side (endothermic reaction side), so when the reaction pressure is high, the thermodynamic equilibrium temperature becomes higher: Ca(OH)2 (solid) + endothermic → CaO (solid) + H2O (gas)

[0020] Specifically, in the decomposition reaction of calcium hydroxide shown above, the thermodynamic equilibrium temperature is approximately 507°C when the water vapor pressure is 0.1 MPa (1.0 atm), whereas the thermodynamic equilibrium temperature is approximately 600°C when the water vapor pressure is 0.47 MPa (4.7 atm).

[0021] The high temperature heat obtained in the heat dissipation step can optionally be used in a heat utilization facility (40), such as a power generation facility.

[0022] In FIG. 1(b), the dotted lines indicate flow paths that are not used in the heat storage stage.

[0023] According to the hybrid heat storage system of the present invention, low-temperature thermal energy is stored in a low-cost sensible heat storage device, and high-temperature thermal energy is stored in a chemical heat storage device. Therefore, in the heat release stage, the chemical heat pump can be operated to generate heat output at a temperature higher than the heat storage temperature.

[0024] The sensible heat storage device that can be used in the present invention is a molten salt heat storage device, and therefore molten salt can be used as the heat medium. Examples of the sensible heat storage device include a thermocline heat storage device (thermocline type sensible heat storage device), a direct or indirect two-tank heat storage device that uses a tank for a low-temperature heat medium and a tank for a high-temperature heat medium, and the like.

[0025] Usable molten salts include carbonate-based molten salts, chloride-based molten salts, nitrate-based molten salts, and fluoride-based molten salts.

[0026] Specifically, examples of carbonate-based molten salts include those containing lithium carbonate, sodium carbonate, potassium carbonate, magnesium carbonate, calcium carbonate, barium carbonate, or any combination thereof. Examples of chloride-based molten salts include those containing lithium chloride, sodium chloride, potassium chloride, magnesium chloride, calcium chloride, barium chloride, zinc chloride, or any combination thereof. Examples of nitrate-based molten salts include those containing lithium nitrate, sodium nitrate, potassium nitrate, magnesium nitrate, calcium nitrate, barium nitrate, or any combination thereof. Examples of fluoride-based molten salts include those containing lithium fluoride, sodium fluoride, potassium fluoride, magnesium fluoride, calcium fluoride, barium fluoride, or any combination thereof.

[0027] Furthermore, examples of combinations of chemical heat storage media and reaction media that can be used in the present invention include combinations of metal hydroxides (and metal oxides) and water, or combinations of metal salt hydrates (and metal salt anhydrides) and water.

[0028] Specifically, the combination of metal hydroxide (and metal oxide) and water may be a combination of calcium hydroxide (and calcium oxide) and water, a combination of magnesium hydroxide (and magnesium oxide) and water, a combination of strontium hydroxide (and strontium oxide) and water, or a combination of barium hydroxide (and barium oxide) and water.

[0029] Furthermore, the combination of a metal salt hydrate and an anhydrous metal salt with water may be a combination of calcium sulfate hydrate (and anhydrous calcium sulfate) with water, or a combination of calcium chloride hydrate (and anhydrous calcium chloride) with water.

[0030] Specifically, the reaction formula between the chemical heat storage medium and the reaction medium is as follows: Ca(OH)2 (solid) + endothermic → CaO (solid) + H2O (gas) Mg(OH)2 (solid) + endothermic → MgO (solid) + H2O (gas) Sr(OH)2 (solid) + endothermic → SrO (solid) + H2O (gas) Ba(OH)2 (solid) + endothermic → BaO (solid) + H2O (gas) CaSO4·0.5H2O (solid) + endothermic → CaSO4 (solid) + 0.5H2O (gas) CaCl2·0.5H2O (solid) + endothermic → CaCl2 (solid) + 0.5H2O (gas)

[0031] <Second mode> A second embodiment of the hybrid thermal storage system of the present invention further comprises a steam turbine (60) and a heat exchanger (70) in addition to the components of the first embodiment.

[0032] In this hybrid heat storage system, in the heat storage stage, the generated steam (H2O) of the reaction medium at the first pressure is supplied to a steam turbine (60) to generate power. This allows the energy of the generated steam of the reaction medium at the first pressure to be converted into electric power and used efficiently.

[0033] In this hybrid heat storage system, in the heat storage stage, at least a part of the heat medium whose temperature has been reduced by heating the chemical heat storage medium (Ca(OH)2) of the chemical heat storage device (10) is reheated by heat exchange with the heat medium from the heat source (30) in the heat exchanger (70) to obtain a reheated heat medium, and the reheated heat medium is stored in the sensible heat storage device (20). This increases the temperature of the heat medium stored in the sensible heat storage device (20), thereby increasing the amount of energy stored in the sensible heat storage device (20).

[0034] Chemical heat storage block 3, the chemical heat storage block (110) of the present invention has a porous substrate (111) having interconnected pores, and a chemical heat storage medium filled in the interconnected pores of the porous substrate, and the porous substrate (111) has through-flow paths (112) for circulating vapor of the reaction medium. Here, the chemical heat storage medium generates heat when it reacts with the reaction medium, and absorbs heat when it is separated from the reaction medium.

[0035] Here, the cross-sectional area of ​​this through flow path can be determined arbitrarily depending on the air permeability of the porous substrate used, the type and amount of the chemical heat storage medium, the intended steam flow rate, etc., and may be, for example, 1% or more, 2% or more, 3% or more, 4% or more, or 5% or more of the porous substrate when viewed in a cross section perpendicular to the flow path of the through flow path, or 30% or less, 20% or less, 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, or 5% or less of the porous substrate. Also, as shown with reference to Figure 4, the chemical heat storage block (120) of the present invention may have two or more through flow paths (122).

[0036] According to the chemical heat storage block (110, 120) of the present invention, the chemical heat storage medium is filled into the communicating pores of the porous substrate, and the porous substrate (111, 121) has through-flow paths (112, 122) for circulating the vapor of the reaction medium, thereby enabling efficient separation and reaction between the chemical heat storage medium and the vapor of the reaction medium.

[0037] In particular, such a chemical heat storage block of the present invention enables efficient operation of the chemical heat storage device, in particular chemical heat pump operation of the chemical heat storage device, and further, a chemical heat storage device using such a chemical heat storage block of the present invention can operate as a chemical heat pump that outputs a temperature higher than the heat storage temperature by increasing the reaction pressure during heat release.

[0038] In such a chemical heat storage block of the present invention, a porous substrate containing a substance selected from the group consisting of silicon oxide, silicon carbide, aluminum nitride, boron nitride, magnesium oxide, aluminum oxide, beryllium oxide, and mixtures thereof can be used as the porous substrate. The porous substrate may be, for example, a foam structure.

[0039] In the chemical heat storage block of the present invention, the combinations of chemical heat storage medium and reaction medium that have been described in relation to the hybrid heat storage system of the present invention can be used.

[0040] In manufacturing the chemical heat storage block of the present invention, a porous substrate such as that described above can be coated with a slurry containing powder of the chemical heat storage medium, dried, and fired as necessary.

[0041] Specifically, for example, when calcium hydroxide (or calcium oxide) is used as the chemical heat storage medium, limestone is burned in a reaction vessel to obtain calcium oxide, water is added to the obtained calcium oxide to cause a hydration reaction to obtain calcium hydroxide slurry, this calcium hydroxide slurry is dehydrated using a pressure filter to increase the solid content concentration, a dispersant is added to the obtained calcium hydroxide slurry, and water is added as needed to adjust the solid content concentration, thereby obtaining calcium hydroxide slurry.

[0042] This calcium hydroxide slurry is then applied to a porous material serving as a support substrate by vacuum impregnation. Here, vacuum impregnation can be carried out by placing the support substrate to which the calcium hydroxide slurry has been applied in a desiccator, reducing the pressure with a vacuum pump, and impregnating the support substrate with the calcium hydroxide slurry. Thereafter, the support substrate impregnated with the calcium hydroxide slurry is placed in an oven and dried, thereby obtaining the chemical heat storage block of the present invention.

[0043] The photograph in FIG. 5 shows a silicon carbide-based porous substrate (left photo), and a chemical heat storage block of the present invention (right photo) manufactured as described above using this silicon carbide-based porous substrate.

[0044] 3 to 5 show a cylindrical chemical heat storage block as the chemical heat storage block of the present invention, but the chemical heat storage block of the present invention is naturally not limited to a cylindrical shape. Therefore, the chemical heat storage block of the present invention may have other shapes, for example, a square prism or a hexagonal prism. It is preferable that the chemical heat storage block of the present invention is a square prism or a hexagonal prism in order to arrange multiple chemical heat storage blocks densely packed together.

[0045] The chemical heat storage block of the present invention can be used in a chemical heat storage device.

[0046] 《Chemical heat storage device》 As shown in FIG. 6, the chemical heat storage device (200) of the present invention using the chemical heat storage block (110) of the present invention has the following features: A double-pipe container having an inner flow path (210) and an outer flow path (220), and One or more chemical heat storage blocks (110) of the present invention arranged in the inner flow path (210); It has.

[0047] In such a chemical heat storage device (200), As shown by the black arrows, a heat transfer medium is circulated through the outer flow path (220), As shown by the white arrows, in the inner flow path (210), the vapor of the reaction medium is circulated through the through flow path (112) of the chemical heat storage block (110) and between the inner wall of the inner flow path (210) and the chemical heat storage block (110).

[0048] In such a chemical heat storage device (200), separation and reaction between the chemical heat storage medium and the reaction medium in the chemical heat storage blocks (110) are promoted, and heat exchange between the heat medium and the chemical heat storage blocks (110) is promoted, so that chemical heat storage can be performed efficiently. Moreover, in such a chemical heat storage device (200), the required heat storage capacity can be easily achieved by changing the number of chemical heat storage blocks (110).

[0049] In Figure 6, the gap between the inner wall of the inner flow path (210) and the chemical heat storage block (110) is shown as being relatively wide, but this is for the purpose of explanation, and in reality, a narrow gap is preferable for promoting heat exchange between the heat medium of the outer flow path and the chemical heat storage block.

[0050] 6 shows a cylindrical chemical heat storage device having cylindrical chemical heat storage blocks as the chemical heat storage device of the present invention, but as described above, the chemical heat storage blocks of the present invention are not limited to being cylindrical. Therefore, the chemical heat storage device of the present invention may be a chemical heat storage device of another shape having chemical heat storage blocks of another shape, for example, a quadrangular prism-shaped chemical heat storage device having quadrangular prism-shaped chemical heat storage blocks, or a hexagonal prism-shaped chemical heat storage device having hexagonal prism-shaped chemical heat storage blocks.

[0051] 7, for example, in the chemical heat storage device (300) of the present invention, a plurality of inner flow paths (310) may be arranged in one outer flow path (320). In this case, as shown by the black arrows, a heat medium is circulated through the outer flow path (320), and as shown by the white arrows, vapor of the reaction medium is circulated through the inner flow path (310). In this case, the required heat storage capacity can be easily achieved by changing the number of inner flow paths (310) arranged in the outer flow path (320).

[0052] In addition, when a plurality of inner flow paths are arranged in one outer flow path, the number of inner flow paths and the shape of the outer flow path can be determined arbitrarily. Therefore, for example, as shown in Fig. 8(a), a chemical heat storage device (400) in which 12 inner flow paths (410) are arranged in a rectangular outer flow path (420), as shown in Fig. 8(b), a chemical heat storage device (500) in which 7 inner flow paths (510) are arranged in a circular outer flow path (520), as shown in Fig. 8(c), a chemical heat storage device (600) in which 7 inner flow paths (610) are arranged in a hexagonal outer flow path (620), as shown in Fig. 8(d), a chemical heat storage device (700) in which 12 inner flow paths (710) are arranged in a rectangular outer flow path (720), and as shown in Fig. 8(e), a chemical heat storage device (800) in which 7 inner flow paths (810) are arranged in a hexagonal outer flow path (820) are possible.

[0053] In Figures 8(a) to (c), cylindrical heat storage blocks are arranged in square, circular, and hexagonal outer flow paths, respectively, while in Figure 8(d), a square heat storage block is arranged in a square outer flow path, and in Figure 8(e), a hexagonal heat storage block is arranged in a hexagonal outer flow path.

[0054] Chemical Heat Storage and Dissipation Method The chemical heat storage and heat release method of the present invention uses the chemical heat storage device of the present invention.

[0055] As shown with reference to Figure 9(a), in the heat storage stage of this method, as shown by the black arrows, a heat medium is circulated through the outer flow path (220), thereby heating the chemical heat storage medium of the chemical heat storage block (110) and removing the reaction medium, thereby generating the chemical heat storage block (110) from which the reaction medium has been removed and vapor of the reaction medium at a first pressure, and this vapor of the reaction medium is extracted as shown by the white arrows.

[0056] Furthermore, as shown with reference to FIG. 9(b), in the heat dissipation stage of this method, the heat medium is circulated through the outer flow path (220) and the vapor of the reaction medium at the second pressure is circulated through the inner flow path (210) to generate heat in the chemical heat storage block (110), and the heat medium supplied to the outer flow path is reheated by the heated chemical heat storage block (110) as indicated by the black arrow, thereby obtaining a reheated heat medium.

[0057] Here, the second pressure, i.e., the pressure of the vapor of the reaction medium circulated through the inner flow path in the heat release stage, is higher than the first pressure, i.e., the pressure of the reaction medium removed from the chemical heat storage medium in the heat storage stage. By making the second pressure higher than the first pressure in this way, the temperature of the heat medium reheated by the chemical heat storage medium in the heat release stage can be made higher than the temperature of the heat medium that heats the chemical heat storage medium in the heat storage stage.

[0058] For the relationship between the second pressure and the first pressure, the difference between the temperature of the heat medium reheated by the chemical heat storage medium in the heat dissipation stage and the temperature of the heat medium that heats the chemical heat storage medium in the heat storage stage, and the relationship between pressure and thermodynamic equilibrium temperature, please refer to the description of the hybrid heat storage system of the present invention. [Example]

[0059] A chemical heat storage and release method was carried out using a chemical heat storage device as shown in FIG.

[0060] Specifically, a cylindrical silicon carbide foam structure (diameter 55 mm, height 50 mm) with a through hole in the center in the axial direction was coated with a slurry containing calcium hydroxide and dried to obtain a chemical heat storage block as shown in Figures 3 and 5. Twenty chemical heat storage blocks obtained in this way were stacked and placed in the inner flow path of a stainless steel double-tube container placed vertically, as shown in Figure 6. The total amount of calcium hydroxide in the double-tube container was approximately 1.7 kg.

[0061] In the heat storage stage, molten salt at 550°C was circulated through the outer flow path of the double-tube vessel from top to bottom for 400 minutes, decomposing the calcium hydroxide in the chemical heat storage block into calcium oxide and water vapor (approximately 0.01 MPa (approximately 10 kPa)), and recovering water. From the amount of water recovered after the heat storage stage was completed, the reaction conversion rate from calcium hydroxide to calcium oxide was estimated to be approximately 77%.

[0062] In the heat dissipation stage, steam at 0.76 MPa (760 kPa) was circulated from the bottom to the top through the inner flow path of the double-tube container, which had an initial temperature of 400°C, to start an exothermic reaction. Here, this steam was made to circulate around the chemical heat storage block and through the flow path in the inner flow path of the double-tube container.

[0063] After the reaction started, the pressure decreased to 0.5 MPa, but recovered to the initial pressure after about 30 minutes. At almost the same time as the pressure reached its maximum during the pressure recovery process, a maximum temperature of 630°C was observed, which is almost the same as the equilibrium temperature corresponding to this maximum pressure.

[0064] Figure 10 shows the temperature between the first and second chemical heat storage blocks from the bottom of the inner flow path of the double-pipe container during the heat dissipation stage, and the water vapor pressure in the inner flow path of the double-pipe container. [Explanation of symbols]

[0065] 10 Chemical heat storage device 20 Sensible heat storage device 30 Heat source 40 Heat utilization equipment 50 Reaction medium reservoir 60 Steam Turbine 70 Heat exchanger 91, 92 Branch valve 110, 120 Chemical heat storage block 111, 121 Porous substrate 112, 122 through-flow channel 200, 300, 400, 500, 600, 700, 800 Chemical thermal storage device 210, 310, 410, 510, 610, 710, 810 Inner flow channel 220, 320, 420, 520, 620, 720, 820 Outer channel

Claims

1. A porous substrate having interconnected pores and a chemical heat storage medium filled in the interconnected pores of the porous substrate, The chemical heat storage medium generates heat when reacting with a reaction medium and absorbs heat when separated from the reaction medium; and The porous substrate has through-flow passages for the flow of the reaction medium vapor. Chemical heat storage block.

2. A double-pipe container having an inner flow path and an outer flow path, and One or more chemical heat storage blocks according to claim 1, which are arranged in the inner flow path; and A heat transfer medium is circulated through the outer flow path; In the inner flow path, vapor of the reaction medium is circulated through the through flow path of the chemical heat storage block and between the inner wall of the inner flow path and the chemical heat storage block. Chemical heat storage device.

3. The chemical heat storage device according to claim 2 , wherein a plurality of the inner flow channels are arranged within one of the outer flow channels.

4. A chemical heat storage and heat release method using the chemical heat storage device according to claim 2 or 3, In the heat storage stage, the heat medium is circulated through the outer flow path, thereby heating the chemical heat storage medium in the chemical heat storage block and removing the reaction medium, thereby generating the chemical heat storage block from which the reaction medium has been removed and vapor of the reaction medium at a first pressure; In the heat dissipation step, the heat medium is circulated through the outer flow path, and the vapor of the reaction medium at a second pressure is circulated through the inner flow path to cause the chemical heat storage block to generate heat, and the heat medium supplied to the outer flow path is reheated by the generated heat chemical heat storage block to obtain the heated heat medium; the second pressure is higher than the first pressure; and The temperature of the heat medium reheated by the chemical heat storage medium in the heat dissipation step is higher than the temperature of the heat medium that heats the chemical heat storage medium in the heat storage step. Chemical heat storage and release methods.

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