JP7490341B2 - Chemical heat storage device and method for storing heat in chemical heat storage material - Google Patents

Description

The present invention relates to a chemical heat storage device and a method for storing heat in a chemical heat storage material.

A known example of a conventional chemical heat storage device is a chemical heat storage device for heating an oxidation catalyst, as described in Patent Document 1. This chemical heat storage device is installed in the exhaust system of an engine, and controls the opening and closing of a valve installed between a supply unit and a reactor according to the temperature of the exhaust gas supplied. This allows the heat storage reaction and the exothermic reaction to be carried out appropriately according to the temperature of the exhaust gas.

JP 2015-14234 A

A chemical heat storage device stores heat from exhaust gases generated by engines of automobiles, factories, waste incineration plants, etc. in a chemical heat storage material to reuse thermal energy. Therefore, it is required to efficiently recover heat from heat sources such as exhaust gases.
An object of the present invention is to provide a chemical heat storage device and a heat storage method for a chemical heat storage material that are capable of promoting a chemical heat storage reaction during heat storage.

As a result of thorough investigation into the above problems, it was discovered that the chemical heat storage reaction can be promoted by restricting the movement of the reaction medium desorbed from the chemical heat storage material during heat storage and making the pressure inside the reactor higher than the pressure on the outlet side, and thus the present invention was completed.
That is, the present invention provides the following chemical heat storage device and heat storage method for a chemical heat storage material.

In order to solve the above problems, the chemical heat storage device of the present invention comprises a reactor that holds a chemical heat storage material therein, and is characterized in that the pressure inside the reactor is maintained at a pressure higher than the pressure outside the reactor.
In the heat storage reaction of the chemical heat storage material, a reaction medium is generated as a gas by applying heat from the outside to the chemical heat storage material. Therefore, when the reactor is closed, the pressure inside the reactor increases. The temperature of the chemical heat storage material during the heat storage reaction is determined by the reaction temperature corresponding to a predetermined pressure, and if the atmosphere is at a high temperature, the separation reaction in the reactor is promoted, and the heat storage reaction can be performed in a shorter time.
On the other hand, if the reactor is heated with the opening of the reactor open in order to separate the chemical heat storage material from the generated reaction medium, the reaction medium desorbed from the chemical heat storage material continues to flow out of the reactor, so that the pressure inside the reactor is maintained at the same level as the external pressure. In other words, the chemical heat storage material in the reactor undergoes a heat storage reaction at a reaction temperature corresponding to the pressure outside the reactor.
According to this chemical heat storage device, the pressure inside the reactor is maintained at a pressure higher than the pressure outside the reactor (the pressure is not lowered below the pressure outside the reactor), so the temperature of the chemical heat storage material held inside can be maintained higher than the reaction temperature at the pressure outside the reactor. Therefore, the heat storage reaction rate is increased, and the effect of promoting the heat storage reaction is achieved.

Furthermore, one embodiment of the chemical heat storage device of the present invention is characterized in that the pressure outside the reactor is the pressure of a destination to which the reactor is connected.
According to this feature, when the reactor is connected to a destination such as a condenser, the pressure inside the reactor is maintained higher than the pressure of the destination connected to the reactor, so that the temperature of the chemical heat storage material becomes higher than the reaction temperature at the pressure of the destination, thereby promoting the heat storage reaction.

Furthermore, one embodiment of the chemical heat storage device of the present invention is characterized in that it is equipped with an outflow rate adjustment means for adjusting the outflow rate of the reaction medium desorbed from the chemical heat storage material, and by controlling the outflow rate adjustment means, the pressure inside the reactor is maintained at a pressure higher than the pressure outside the reactor.
According to this chemical heat storage device, by controlling the outflow amount adjustment means that adjusts the outflow amount of the reaction medium desorbed from the chemical heat storage material, the pressure inside the reactor can be maintained at a pressure higher than the pressure outside the reactor with a simple operation. And, by increasing the pressure inside the reactor, the temperature of the chemical heat storage material held inside can be maintained higher than the reaction temperature at the pressure outside the reactor. Therefore, the heat storage reaction rate is increased, and the effect of promoting the heat storage reaction is achieved.

Furthermore, one embodiment of the chemical heat storage device of the present invention is characterized in that it comprises a control unit that controls the outflow amount adjustment means.
According to this feature, since the control unit for controlling the outflow amount adjusting means is provided, the progress of the reaction can be automatically controlled based on the preset settings.

Furthermore, in one embodiment of the chemical heat storage device of the present invention, the outflow rate adjustment means is characterized in that it is controlled based on the temperature value of the chemical heat storage material, the temperature value of the reactor, the pressure value of the reactor, and the amount of change in the temperature of the heat medium that supplies heat to the chemical heat storage material.
According to this feature, the outflow amount adjustment means is controlled based on the temperature value of the chemical heat storage material, the temperature value or pressure value of the reactor, or the amount of change in the temperature of the heat medium, so that it is possible to appropriately control the reaction temperature of the chemical heat storage material and the pressure inside the reactor during heat storage, and maintain a state in which the chemical heat storage reaction is promoted.

Furthermore, one embodiment of the chemical heat storage device of the present invention is characterized in that the outflow amount adjusting means controls based on a preset time.
According to this chemical heat storage device, the outflow time of the reaction medium is set in advance based on the type and temperature of the heat medium, the type and reaction mode of the chemical heat storage material, and the reaction scale, etc., so that an efficient chemical heat storage reaction occurs. Therefore, the chemical heat storage reaction can be easily promoted without detailed control.

The chemical heat storage device of the present invention for solving the above problems is characterized in that it comprises a reactor that holds a chemical heat storage material therein, and maintains the temperature of the chemical heat storage material at a temperature higher than the reaction temperature at the pressure outside the reactor.
If the temperature of the chemical heat storage material increases, the reaction rate increases and the heat storage reaction is promoted. According to the chemical heat storage device of the present invention, the temperature of the chemical heat storage material is maintained at a temperature higher than the reaction temperature at the pressure outside the reactor, so that the heat storage reaction rate is improved and the heat storage reaction is promoted.

The heat storage method of the chemical heat storage material of the present invention for solving the above problems is a heat storage method of the chemical heat storage material in which heat is stored in a chemical heat storage material held inside a reactor, characterized in that the heat storage reaction is carried out under the following conditions <1> or <2>.
<1> The pressure inside the reactor is maintained at a pressure higher than the pressure outside the reactor.
<2> The temperature of the chemical heat storage material is maintained at a temperature higher than the reaction temperature at the pressure outside the reactor.
According to this heat storage method, the pressure inside the reactor is maintained at a pressure higher than the pressure outside the reactor, thereby maintaining the reaction temperature of the chemical heat storage material high and further promoting the heat storage reaction.
In addition, by maintaining the temperature of the chemical heat storage material at a temperature higher than the reaction temperature at the pressure outside the reactor, it is possible to achieve the effect of further promoting the heat storage reaction.

The present invention provides a chemical heat storage device and a method for storing heat in a chemical heat storage material that can promote the chemical heat storage reaction during heat storage.

FIG. 2 is a reaction schematic diagram of chemical heat storage in the chemical heat storage device according to the first embodiment of the present invention. FIG. 1 is a schematic explanatory diagram showing a structure of a chemical heat storage device according to a first embodiment of the present invention. FIG. 4 is an operational schematic diagram showing an example of valve operation during heat storage according to the present invention. FIG. 2 is a diagram showing an example of a graph showing the relationship between pressure and reaction temperature associated with opening and closing of a valve during heat storage in the present invention. 5 is a flowchart showing an example of valve operation during heat storage according to the present invention. FIG. 11 is a schematic explanatory diagram showing a structure of a chemical heat storage device equipped with a valve control device according to a second embodiment of the present invention. FIG. 11 is a schematic explanatory diagram showing the structure of a chemical heat storage device according to a third embodiment of the present invention.

Below, preferred embodiments of the present invention will be described in detail with reference to the drawings. Note that the chemical heat storage device and the heat storage method of the chemical heat storage material described in the embodiments are merely examples for explaining the chemical heat storage device and the heat storage method of the chemical heat storage material according to the present invention, and are not limited to these as long as they provide similar effects.

[Chemical heat storage device]
The chemical heat storage device of the present invention is a chemical heat storage device that heats the chemical heat storage material to separate it into a heat storage product and a generated gas during heat storage, and reacts the heat storage product with a reactant gas to generate the chemical heat storage material during heat dissipation. Here, the generated gas generated during heat storage and the reactant gas supplied during heat dissipation are the same type of substance, and the generated gas may be recovered by a condenser and reused as a reactant gas, or the generated gas may be released into the atmosphere during heat storage, and another reactant gas of the same type may be used during heat dissipation. The generated gas and the reactant gas may be referred to as "reaction media".

A typical chemical heat storage (heat release) reaction is, for example, the reaction represented by the following formula (1).
When heat Q is applied to a solid chemical heat storage material AB, a solid heat storage product A and a gaseous reaction medium B are generated. This reaction is a reversible equilibrium reaction, and when heat is released, the heat storage product A reacts with the reaction medium B. Note that "(s)" in the formula represents the solid state, and "(g)" in the formula represents the gaseous state.

A simplified schematic diagram of a chemical heat storage device using this chemical heat storage is shown in FIG. 1. Here, the left side of the figure is a reactor, and the right side of the figure is a condenser for condensing and recovering the reaction medium generated by the heat storage reaction. In chemical heat storage, the reaction medium B(g) is generated by adding heat _QH on the reactor side, and the generated reaction medium B(g) moves to the condenser on the right side due to the pressure difference. On the condenser side, the temperature of the reaction medium B(g) is reduced by dissipating the heat _QL possessed by the reaction medium B(g), and the reaction medium B(g) is liquefied by a condensation reaction to become the reaction medium B(l). Then, the reaction medium B(g) is liquefied to become the reaction medium B(l), and the pressure in the condenser is reduced, so the reaction medium B(g) generated in the reactor can naturally move to the condenser side.

During heat release, the reaction proceeds in the opposite direction, and the reaction medium B(l) is vaporized into the reaction medium B(g) by applying heat _QL to the reaction medium B(l) on the condenser side, and the reaction medium B(g) and the heat storage product A(s) are reacted on the reactor side to form the chemical heat storage material AB(s), and the heat _QH is released by the exothermic reaction. Note that when the internal pressure on the reactor side is lower than the internal pressure on the condenser side, the internal pressure on the condenser side decreases due to the opening of the valve, so that the reaction medium B(l) vaporizes to become the reaction medium B(g) without applying heat _QL , and can naturally move to the reactor side.

Chemical heat storage devices store exhaust heat generated by automobile engines, factories, waste incineration plants, etc. in chemical heat storage materials, and when heat is needed, release the heat from the heat storage product to utilize it. Note that chemical heat storage devices are transportable devices, and may be transported to heat demand areas where heat is needed, or may be fixed in a specified location and used to supply heat by release when there is no heat supply from the heat medium.

The chemical heat storage device of the present invention is characterized by comprising a reactor that holds a chemical heat storage material inside, and maintaining the pressure inside the reactor at a pressure higher than the pressure outside the reactor. From another perspective, the chemical heat storage device of the present invention is characterized by comprising a reactor that holds a chemical heat storage material inside, and maintaining the temperature of the chemical heat storage material at a temperature higher than the reaction temperature at the pressure outside the reactor.

[First embodiment]
2 is a schematic diagram showing the structure of a chemical heat storage device 1a according to a first embodiment of the present invention. This chemical heat storage device 1a has a reactor 2 that holds a chemical heat storage material 4, and a condenser 3 that condenses and stores the product gas generated from the chemical heat storage material 4. The inside of the reactor 2 and the inside of the condenser 3 are airtightly connected via a communication part 7, and the communication part 7 has a valve V1 that can control the movement of the product gas. In addition, a heat exchange part 5 through which a heat medium such as exhaust gas passes is provided inside the reactor 2.
Each component will be described in detail below.

(Chemical heat storage material)
The chemical heat storage material 4 is a chemical substance that is separated into a heat storage product and a generated gas when heated, and releases heat by the reverse reaction. For example, examples of the heat storage product and generated gas include calcium oxide (CaO) and water vapor (H ₂ O), calcium chloride (CaCl ₂ ) and water vapor (H ₂ O), calcium bromide (CaBr ₂ ) and water vapor (H ₂ O), calcium iodide (CaI ₂ ) and water vapor (H ₂ O), magnesium oxide (MgO) and water vapor (H ₂ O), magnesium chloride (MgCl ₂ ) and water vapor (H ₂ O), zinc chloride (ZnCl ₂ ) and water vapor (H ₂ O), strontium chloride (SrCl ₂ ) and ammonia (NH ₃ ), and strontium bromide (SrBr ₂ ) and ammonia (NH ₃ ). From the viewpoint of ease of procurement during heat dissipation, the chemical heat storage material 4 preferably uses water vapor as the product gas and the reactant gas.

The structure and shape of the chemical heat storage material 4 are not particularly limited, and may be, for example, a powder, a granule, a pellet, or a flake. It may also be a molded body obtained by molding a powder, or a chemical heat storage material 4 supported on a porous body. From the viewpoint of having a large surface area to enhance reactivity, a powder shape is preferable.

Furthermore, the powdered chemical heat storage material 4 may be packed in a container or bag made of a metal mesh to form a cartridge. By forming a cartridge, it is possible to prevent the powdered chemical heat storage material 4 from flowing out of the reactor 2 and to prevent the chemical heat storage material 4 from being unevenly positioned inside the reactor 2. Furthermore, by forming a cartridge, it becomes easier to replace the chemical heat storage material 4, and it is also easy to handle.

(Reactor)
The reactor 2 is configured to hold the chemical heat storage material 4 and is made of a sealable structure. The shape and material of the reactor 2 are not particularly limited, but it is preferable that the reactor 2 has pressure resistance. By having pressure resistance, the change in the internal volume due to the change in the pressure inside the reactor 2 is suppressed, and the effect of easily controlling the internal pressure is achieved.

The reactor 2 is provided with an opening 6 through which the reaction medium desorbed from the chemical heat storage material 4 flows in and out, and the opening 6 is connected to the communication section 7. The communication section 7 is also provided with a valve V1 for adjusting the outflow amount of the reaction medium (the inflow amount during heat dissipation). The pressure inside the reactor can be increased by restricting the outflow of the reaction medium generated by heating with the valve V1. That is, by controlling the opening and closing of the valve V1, the pressure inside the reactor can be adjusted to be maintained at or above the pressure on the outlet side (condenser side) of the valve V1. Also, by maintaining the pressure inside the reactor at or above the pressure on the outlet side, it is possible to maintain the temperature of the chemical heat storage material at a temperature higher than the reaction temperature at the pressure outside the reactor. That is, the heat storage reaction can be promoted by restricting the outflow of the reaction medium. The adjustment of the pressure inside the reactor 2 by the valve V1 will be described later.

(Outflow amount adjustment means)
The chemical heat storage device 1a of the first embodiment of the present invention includes a valve V1 as an outflow amount adjustment means. The outflow amount adjustment means is for adjusting the outflow amount of the reaction medium desorbed from the chemical heat storage material during the heat storage reaction, and examples of the outflow amount adjustment means include a valve for opening and closing the opening of the reactor 2 and a throttle part for reducing the diameter of the communication part. When the reaction medium moves toward the connection destination, the movement is restricted by the outflow amount adjustment means, so that the internal pressure of the reactor can be maintained higher than the pressure of the connection destination.

Valve V1 may be a control valve that is controlled in two stages, fully open or fully closed, or a control valve that adjusts the opening degree in stages. The former control valve can adjust the pressure inside reactor 2 with a simple structure. The latter control valve has the advantage of being able to precisely adjust the pressure inside reactor 2.

A plurality of openings 6 may be formed in the reactor 2, and each opening 6 may be provided with a communication section 7 and a valve V1, and the pressure inside the reactor 2 may be adjusted by the plurality of valves V1. This allows the pressure inside the reactor 2 to be more precisely controlled. The arrangement of the plurality of openings 6 may be adjacent to the reactor 2, or may be different from the reactor 2. When the openings 6 are arranged in close proximity to the reactor 2, it is not necessary to form a complex piping structure, and the structure of the reactor 2 can be simplified. When the openings 6 are arranged in different positions in the reactor 2, the openings 6 can be arranged in close proximity to the chemical heat storage material 4 arranged inside the reactor 2, so that the reaction medium generated from the chemical heat storage material 4 can be quickly flown in and out.

The reactor 2 may be a structure that is removable from the chemical heat storage device 1a. By making it a removable structure, only the reactor 2 that holds the chemical heat storage material 4 can be transported to a heat demand area that requires heat dissipation. Also, only the chemical heat storage material 4 inside the reactor 2 may be enclosed in a sealable container or bag and transported to the heat demand area.

The reactor 2 may also have a heat-retaining section (not shown) for keeping the reactor 2 warm. The heat-retaining section is made of a material that suppresses heat dissipation, such as a heat insulating material or a heat-reflecting material, and is provided to cover the periphery of the reactor 2. The heat-retaining material is made of a material that suppresses heat dissipation from the reactor 2, and examples of the material include foamed resins such as foamed polyethylene and polystyrene foam, synthetic resins, and inorganic materials. The heat-reflecting material is made of a material that can reflect radiant heat emitted from the reactor 2. Examples of materials that can reflect radiant heat include metals such as aluminum, iron, copper, brass, silver, gold, platinum, nickel, stainless steel, chromium, and tungsten. Examples of non-metals include quartz glass, alumina ceramics, magnesia ceramics, and fireproof bricks.

(Heat exchange section)
The reactor 2 has a heat exchange unit 5 for transferring heat between the chemical heat storage material 4 held inside and the outside, a heat medium supply port 8 for supplying a heat medium to the heat exchange unit 5, and a heat medium discharge port 9 for discharging the heat medium from the heat exchange unit 5. In addition, valves V2 and V3 are provided in the piping through which the heat medium circulates via the heat medium supply port 8 and the heat medium discharge port 9, respectively, to control the supply and discharge of the heat medium to the heat exchange unit 5.

The heat exchange unit 5 may have any shape as long as it can transfer heat between the chemical heat storage material 4 stored inside the reactor 2 and the outside, and is, for example, composed of a heat exchange tube installed in a serpentine manner inside the reactor 2, the inner cylinder of a double-cylindrical reactor, etc. Also, heat exchange may be performed through the outer wall of the reactor 2.
Alternatively, a heat medium may be supplied to the inside of the reactor 2 and the heat medium and the chemical heat storage material 4 may be brought into direct contact with each other, thereby supplying heat from the heat medium to the chemical heat storage material 4 .

The heat medium may be any temperature that can supply heat to the chemical heat storage material 4, and may be a fluid such as a gas or liquid, or a solid. From the viewpoint of excellent heat transfer efficiency, it is preferable to use a fluid. Furthermore, from the viewpoint of excellent handling properties, it is particularly preferable to use a gas.

(Condenser)
The chemical heat storage device 1a of the first embodiment of the present invention includes a condenser 3 as a connection destination of the reactor 2. The condenser 3 is a structure for storing the reaction medium generated as a gas from the chemical heat storage material 4 during heat storage as a liquid state reaction medium 10, and the gas phase part at the top of the condenser 3 and the opening 6 are connected by a communication part 7. The condenser 3 is adjusted to a temperature at which the reaction medium generated as a gas is condensed, and when the gas state reaction medium flows into the condenser 3, it is condensed into a liquid state. The adjustment of the temperature of the condenser 3 is not particularly limited, and may be cooled by a cooling device or the like, or may be cooled by natural heat dissipation.

The inside of the reactor 2 and the inside of the condenser 3 are airtightly connected via the communication part 7, and the inside of the condenser 3 is negative pressure. This allows the reaction medium generated as a gas from the chemical heat storage material 4 to naturally move to the condenser 3 side. When the gaseous reaction medium is condensed to a liquid state in the condenser 3, the internal pressure of the condenser 3 decreases, so that the reaction medium generated as a gas from the chemical heat storage material 4 can continue to naturally move to the condenser 3 side.
The inside of the reactor 2 and the inside of the condenser 3 do not need to be airtightly connected. In this case, the condenser 3 is used simply to collect the reaction medium generated as a gas from the chemical heat storage material 4 before it is released into the atmosphere.
Also, the reaction medium may be discharged to the atmosphere without providing the condenser 3 .

(Communicating Part)
The communication part 7 is not particularly limited as long as it communicates between the inside of the reactor 2 and the inside of the condenser 3, and examples thereof include piping. In addition, the inside of the reactor 2 and the inside of the condenser 3 may be directly communicated with each other without using piping.

[Operation of the chemical heat storage device during heat storage]
During heat storage, the heat medium supply port 8 and the heat medium discharge port 9 are opened to allow the heat medium to flow through the heat exchange unit 5. In addition, the valve V1 is opened to connect the reactor 2 and the condenser 3. As a result, the chemical heat storage material 4 is heated by the heat medium supplied to the heat exchange unit 5, and separated into a heat storage product and a generated gas. The generated gas passes through the valve V1 and moves to the condenser 3. The generated gas that flows into the condenser 3 is cooled and stored in the condenser 3 as a liquid reaction medium 10. The cooling method may be cooling by leaving it alone with outside air, or cooling by a cooling device (not shown).

Here, the chemical heat storage device 1a of the present invention can control chemical heat storage while maintaining the pressure inside the reactor 2 at a pressure value equal to or higher than the pressure on the outlet side of the valve V1, i.e., the condenser 3 side, by opening and closing the valve V1 at least once or more times, preferably twice or more times, during the progress of chemical heat storage. By maintaining the pressure inside the reactor 2 high, the reaction temperature of the chemical heat storage material 4 can be maintained at a temperature higher than the reaction temperature at the pressure outside the reactor, so that the heat storage reaction of the chemical heat storage material 4 is carried out at a higher temperature. Therefore, the heat storage reaction rate is improved, and the heat storage time is shortened. In addition, the pressure inside the reactor 2 is increased, and when the valve V1 is opened, the outflow of the reaction medium can be promoted. Therefore, by repeatedly opening and closing the valve V1, the outflow of the reaction medium is promoted, and the heat storage time is shortened. In more detail, the operation will be described below with reference to the operation schematic diagram of FIG. 3, the diagram showing the reaction temperature corresponding to the pressure in FIG. 4, and the flowchart in FIG. 5.

(Prior Art Valve Operation)
First, the operation schematic diagram (a) shown in the upper part of Fig. 3 shows the valve operation during conventional heat storage. Here, T_open indicates the temperature change of the chemical heat storage material, and P_open indicates the pressure change inside the reaction vessel. Also, Valve indicates the opening and closing operation of the valve V1, and the vertical axis CLOSE indicates that the valve V1 is closed, and the vertical axis OPEN indicates that the valve V1 is open. The horizontal axis indicates the passage of time, and the numbers show an example.

When the chemical heat storage material 4 is heated through the heat exchange unit 5 by the heat medium supplied from the heat medium supply port 8 with the valve V1 closed, the chemical heat storage material 4 is heated with the temperature (Th) of the heat medium as the upper limit. At this time, the pressure inside the reaction vessel becomes Ph, and the reaction temperature becomes Th.
Next, when the valve V1 is opened at time 0, the pressure inside the reactor 2 drops to P, and the reaction temperature also drops to TH and reaches an equilibrium state. When the reaction temperature drops to TH, the temperature of the chemical heat storage material also drops to TH. Then, by maintaining the valve V1 in an open state, the reaction medium generated from the chemical heat storage material 4 flows out of the reactor 2, so that the pressure inside the reactor 2 is maintained equal to the external pressure, and the reaction temperature is also equal to the reaction temperature TH at the external pressure. Therefore, the heat storage reaction proceeds with the temperature of the chemical heat storage material also maintained at TH.

Here, the valve operation is explained using a graph showing the reaction temperature corresponding to the pressure. FIG. 4 is a diagram showing an example of a graph showing the reaction temperature corresponding to the pressure. The graph PH on the left side shows the reaction temperature of the chemical heat storage material 4 corresponding to the pressure inside the reactor 2, and the graph PL on the right side shows the condensation temperature of the reaction medium B corresponding to the pressure inside the condenser 3. The horizontal axis shows the reciprocal of the temperature, and the vertical axis shows the logarithm of the pressure. As shown in this figure, when the valve V1 is opened, the pressure inside the reactor 2 becomes equal to the pressure P on the condenser 3 side. Therefore, when the valve V1 is maintained in an open state, the pressure inside the reactor 2 is maintained at a pressure equal to the pressure P on the condenser 3 side, and the reaction temperature of the chemical heat storage material 4 is maintained at the reaction temperature at this pressure P.

Since the temperature on the condenser 3 side is controlled to be lower than TL by natural heat radiation or cooling, the gaseous reaction medium that has flowed into the condenser 3 is condensed into liquid, and the internal pressure of the condenser 3 decreases. Due to this condensation reaction, if the valve V1 is maintained in an open state, the gaseous reaction medium in the reactor 2 naturally moves to the condenser 3, and the heat storage reaction proceeds.
That is, when the valve V1 is opened, the pressure of the reactor 2 decreases from Ph to P, and at the same time, the reaction temperature of the chemical heat storage material 4 held in the reactor 2 also decreases from Th to TH. In addition, the temperature of the chemical heat storage material 4 held in the reactor 2 also decreases toward TH. After that, the state of the vapor pressure P on the condenser 3 side is maintained, and the temperature of the chemical heat storage material 4 is also maintained at TH.
Then, when the heat storage reaction is completed, the generation of the reaction medium stops and the movement of gas ceases, so that the temperature of the reactor 2 rises to the upper limit value Th.

Next, the control of valve operation in the prior art will be described in the flowchart (a) of FIG. 5. In the control of valve operation, after starting heating of the chemical heat storage material 4, it is confirmed whether the temperature of the chemical heat storage material 4 has reached the upper limit value. If the upper limit value has been reached, the valve V1 is opened, and on the other hand, if the upper limit value has not been reached, the above loop is repeated until the temperature reaches the upper limit value. Here, the upper limit value is the temperature derived from the heat medium used, and is Th in this embodiment.

As described above, after valve V1 is opened, the temperature of reactor 2 drops to TH, and the heat storage reaction proceeds in that state. Then, when the heat storage reaction ends, the generation of the reaction medium stops, and the temperature of reactor 2 rises to the upper limit value Th.

In the control after the valve V1 is opened, the temperature of the reactor 2 is continuously detected and it is confirmed whether the temperature of the reactor 2 has reached the upper limit value Th. If the upper limit value Th is reached, it is determined that the heat storage reaction has ended, and the valve V1 is closed. On the other hand, if the upper limit value Th is not reached, the above loop is repeated until the temperature reaches the upper limit value. That is, after the valve V1 is opened, if the temperature of the reactor that has once dropped to TH reaches the upper limit value Th again due to the progress of chemical heat storage, the chemical heat storage is terminated.
Therefore, chemical heat storage proceeds at a temperature TH lower than Th.

(Valve operation in the present invention)
On the other hand, the operation schematic diagram (b) shown in the lower part of Figure 3 shows an example of valve operation in chemical heat storage according to the present invention. Here, T_o/c indicates the temperature change of the chemical heat storage material 4, and P_o/c indicates the pressure change inside the reactor 2. Also, Valve indicates the operation of the valve V1.

When the chemical heat storage material 4 is heated through the heat exchange unit 5 by the heat medium supplied from the heat medium supply port 8 with the valve V1 closed, the chemical heat storage material 4 is heated with the temperature of the heat medium as the upper limit, and an equilibrium state is reached. At this time, the temperature of the chemical heat storage material 4 becomes Th, and the vapor pressure of the generated gas becomes Ph.
Next, when the valve V1 is opened at time 0, the pressure inside the reactor 2 drops to P, and the temperature of the chemical heat storage material 4 also drops to TH and reaches an equilibrium state. Here, the valve V1 is closed again. Then, the pressure inside the reactor 2 rises again from P toward Ph, and at the same time, the temperature of the chemical heat storage material 4 also rises again toward Th, which is the temperature derived from the heat medium supplied from the heat exchanger 5. After the pressure inside the reactor 2 reaches Ph, or after the temperature of the chemical heat storage material 4 reaches Th, when the valve V1 is opened again, the pressure decreases to P and the temperature drops to TH. These opening and closing operations of the valve V1 are repeated at least once. As a result, the reactor 2 is opened in a state in which the pressure inside the reactor 2 is higher than the external pressure, and the outflow of the reaction medium is promoted. In addition, since the temperature of the chemical heat storage material 4 can be maintained in a high temperature state, it is possible to promote the heat storage reaction.

When chemical heat storage has progressed sufficiently, product gas is no longer produced and the pressure inside reactor 2 gradually stops rising. As a result, the pressure increase per unit time becomes smaller. When chemical heat storage has progressed sufficiently, the opening and closing operation of valve V1 is stopped, valve V1 is opened, and the heat storage reaction is carried out to the end. The end of the heat storage reaction is determined when the temperature of reactor 2 rises to the upper limit value Th.

Next, the control of the valve operation of the present invention will be described similarly using the flowchart (b) of Fig. 5. First, after starting heating the chemical heat storage material 4, it is confirmed whether the temperature of the chemical heat storage material 4 has reached the upper limit value. If the upper limit value is reached, the valve V1 is opened, and on the other hand, if the upper limit value is not reached, the loop is repeated until the temperature reaches the upper limit value. Here, the upper limit value is the temperature derived from the heat medium used, and is Th in this embodiment.
After opening the valve V1, it is confirmed whether or not the pressure in the reactor 2 has reached the lower limit. If the pressure in the reactor 2 has not reached the lower limit, the above loop is repeated until the pressure in the reactor 2 reaches the lower limit.

On the other hand, when the pressure in the reactor 2 reaches the lower limit, it is checked whether the temperature of the chemical heat storage material 4 is maintained at the upper limit. That is, when the temperature of the chemical heat storage material 4 is at the upper limit, i.e., Th, even when the valve V1 is open, it is determined that no reaction medium is being generated from the chemical heat storage material 4, and the heat storage reaction has ended. Then, the valve V1 is closed, heating is stopped, and chemical heat storage is terminated.

If the temperature of the chemical heat storage material 4 drops and is not maintained at the upper limit value, valve V1 is closed and the temperature of the chemical heat storage material 4 is raised to the upper limit value, and when valve V1 is opened, the loop is repeated until the pressure is at the lower limit value and the temperature of the chemical heat storage material 4 is maintained at the upper limit value.
Therefore, chemical heat storage progresses while the temperature of the chemical heat storage material 4 fluctuates between the temperatures Th and TH.

The determination of whether the temperature of the chemical heat storage material 4 has reached the upper limit and whether the pressure value of the reactor 2 has reached the lower limit may be made by calculating the changes in temperature and pressure ΔT and ΔP, respectively, and determining that the upper limit or lower limit has been reached when the small changes reach almost 0. Alternatively, the upper limit or lower limit may be determined to be reached when the change decreases from the maximum change to a predefined percentage or less (for example, 5% or less). The upper limit of the temperature and the lower limit of the pressure of the reactor 2 may be set in advance based on the mode of chemical heat storage.

In addition, in the first embodiment, the decision to control the opening and closing of valve V1 is made based on the upper and lower limit values of the temperature of the chemical heat storage material 4 and the pressure of the reactor 2, but the decision may be made based on any value between the upper and lower limit values.
Furthermore, instead of the temperature of the chemical heat storage material 4, control can also be performed using something that represents the temperature condition inside the reactor 2, such as the temperature value of the reactor 2 or the amount of change in the temperature of the heat medium.

The time, number of times, and timing for opening or closing valve V1 are not limited as long as the effects of the present invention are achieved. For example, they can be changed as appropriate depending on the type of chemical heat storage material 4, the mode of chemical heat storage, the reaction temperature provided by the heat medium, the pressure during the reaction, or the scale of the reaction. For example, the timing for closing valve V1 may be simultaneous with the temperature changing from Th to TH, or it may be before the temperature changes to TH, or it may be after a certain time has passed since the temperature changes to TH.

The more specific timing for opening and closing the valve V1 during the progress of chemical heat storage may be determined based on the temperature value of the chemical heat storage material 4, the temperature value of the reactor 2, the pressure value of the reactor 2, and the amount of change in the temperature of the heat medium that provides heat to the chemical heat storage material 4. Here, the temperature value of the reactor may be a direct measurement of the temperature inside the reactor, or the temperature of the generated gas in the flow path on the reactor side near the valve V1. The temperature of the chemical heat storage material 4 may be calculated based on this measured value. In addition, the pressure value of the reactor may also be a direct measurement of the pressure inside the reactor 2, or the pressure value on the reactor side near the valve V1. The reaction temperature of the chemical heat storage material is determined based on these measured values, so the progress of chemical heat storage can be determined.

After chemical heat storage is completed, the heat medium supply port 8 and the heat medium discharge port 9 are closed to stop the flow of the heat medium. Next, the reactor 2 is cooled to room temperature with the valve V1 closed. The temperature can be reduced to room temperature by leaving the chemical heat storage device 1a as it is and dissipating heat, or by supplying cooling water to the heat exchanger 5. By closing the valve V1 while the reactor 2 is at a high temperature and cooling to room temperature in a sealed state, it is possible to prevent the inflow of external gas due to a drop in internal pressure when the temperature is reduced. In addition, by sealing the reactor 2, the internal pressure of the reactor 2 is reduced, so the operation of reducing the internal pressure during heat dissipation can be shortened.

(Valve opening and closing control by timer)
In addition, the valves V1 and V2 may be automatically opened and closed according to a preset time table. That is, instead of controlling the opening and closing of the valves in accordance with the progress of chemical heat storage during heat storage as described above, a time table for opening and closing the valves is preset and executed based on the type and temperature of the heat medium, the type of the chemical heat storage material 4, the type of the equilibrium reaction, the scale of the chemical heat storage device 1a, and the pressure resistance and heat resistance of the chemical heat storage device 1a, etc., related to the chemical heat storage.

[Other aspects of the heat storage device]
Another embodiment of the chemical heat storage device 1 will be exemplified below.
Second embodiment
FIG. 6 is a schematic explanatory diagram showing the structure of a chemical heat storage device 1b according to a second embodiment of the present invention.
This chemical heat storage device 1b is the chemical heat storage device 1a of the first embodiment, provided with a control unit 20 that controls the opening and closing of the valve V1. The control unit 20 automatically controls the opening and closing of the valve V1 based on the temperature value of the chemical heat storage material, the temperature value of the reactor, the pressure value of the reactor, the amount of change in the temperature of the heat medium that supplies heat to the chemical heat storage material 4, and the like. According to this chemical heat storage device 1b, it is possible to provide a chemical heat storage device that can reliably and easily manage the progress of chemical heat storage without the need for monitoring or valve operation by workers during chemical heat storage or heat release.

[Third embodiment]
FIG. 7 is a schematic explanatory diagram showing the structure of a chemical heat storage device 1c according to a third embodiment of the present invention.
This chemical heat storage device 1c is the chemical heat storage device 1a of the first embodiment, except that the condenser 3 and the communicating part 7 are removed, and the opening 6 is connected to the outside. Therefore, in the chemical heat storage device 1c, the reaction medium generated during heat storage is not recovered in the condenser 3, but is released into the atmosphere. In addition, an openable and closable valve V4 is provided in the opening 6, and the effects of the present invention are achieved by controlling the opening and closing of the valve V4, similar to the valve V1 of the first and second embodiments.

The chemical heat storage device 1c of the third embodiment does not have a condenser 3, so the chemical heat storage device of the present invention can be constructed with a simple device configuration. This has the advantages of making the device more compact and reducing transportation costs.

The above-described embodiment shows an example of a chemical heat storage device. The chemical heat storage device according to the present invention is not limited to the above-described embodiment, and the chemical heat storage device according to the above-described embodiment may be modified within the scope of the gist of the claims.

The chemical heat storage device of the present invention is used in a method for effectively utilizing exhaust heat generated from factories, waste incineration plants, etc. For example, it can be used in a method for storing heat in the chemical heat storage device of the present invention in a heat supply area where exhaust heat is generated, and transporting the chemical heat storage device to a heat demand area where heat is required and releasing the heat. It can also be used in a method for storing heat during the hours when exhaust heat is generated and releasing it during the hours when heat is required, in the same installation location, such as storing heat during the day and releasing it at night.

1a, 1b, 1c...chemical heat storage device, 2...reactor, 3...condenser, 4...chemical heat storage material, 5...heat exchange section, 6...opening, 7...connection section, 8...heat medium supply port, 9...heat medium discharge port, 10...liquid reaction medium, 20...control section, V1, V2, V3, V4...valves,

Claims (6)

A reactor for holding a chemical heat storage material therein;
A chemical heat storage device in which the chemical heat storage material is heated during heat storage to move a reaction medium desorbed from the chemical heat storage material to a condenser side,
An outflow amount adjustment means for adjusting the outflow amount of the reaction medium desorbed from the chemical heat storage material,
During heat storage, the outflow rate control means controls the outflow rate of the reaction medium to the condenser, thereby maintaining the internal pressure of the reactor at a pressure higher than the pressure of the condenser, and then the outflow rate control means promotes the outflow rate of the reaction medium to the condenser. A chemical heat storage device. The chemical heat storage device according to claim 1, further comprising a control unit that controls the outflow rate adjustment means. The chemical heat storage device according to claim 1 or 2, characterized in that the outflow rate adjustment means controls based on the temperature value of the chemical heat storage material, the temperature value of the reactor, the pressure value of the reactor, and the amount of change in the temperature of the heat medium that supplies heat to the chemical heat storage material. The chemical heat storage device according to any one of claims 1 to 3, characterized in that the outflow rate adjustment means is controlled based on a preset time. A reactor for holding a chemical heat storage material therein;
A chemical heat storage device in which the chemical heat storage material is heated during heat storage to move a reaction medium desorbed from the chemical heat storage material to a condenser side,
An outflow amount adjustment means for adjusting the outflow amount of the reaction medium desorbed from the chemical heat storage material,
During heat storage, the outflow rate adjustment means is controlled to suppress the outflow rate of the reaction medium to the condenser, thereby maintaining the temperature of the chemical heat storage material at a temperature higher than the reaction temperature at the pressure of the condenser, and then the outflow rate adjustment means is used to promote the outflow rate of the reaction medium to the condenser. A chemical heat storage device. A method for storing heat in a chemical heat storage material , in which a chemical heat storage material held inside a reactor is heated to move a reaction medium desorbed from the chemical heat storage material to a condenser side to store heat,
An outflow amount adjustment means for adjusting the outflow amount of the reaction medium desorbed from the chemical heat storage material,
During heat storage, the outflow rate adjustment means is controlled to suppress the outflow rate of the reaction medium to the condenser, thereby carrying out a heat storage reaction under the following conditions <1> or <2> , and then the outflow rate adjustment means is used to promote the outflow rate of the reaction medium to the condenser. This is a heat storage method for a chemical heat storage material.
<1> The pressure inside the reactor is maintained at a pressure higher than the pressure in the condenser.
<2> The temperature of the chemical heat storage material is maintained at a temperature higher than the reaction temperature at the pressure of the condenser.