JP6471947B1 - Chemical heat storage material and method for producing the same, chemical heat pump and method for operating the same - Google Patents

Abstract

[Problem] To provide a chemical heat storage material that exhibits higher reaction rate and can realize heat storage at a lower temperature in a chemical heat storage material that performs heat storage using dehydration reaction of hydroxide of an alkaline earth metal.
A chemical heat storage material includes a hydroxide and / or oxide of an alkaline earth metal and a metal acid salt. The chemical heat storage material further includes an alkali metal compound, and the amount of the alkali metal compound is 0.1 to 50 mol% with respect to the hydroxide and / or oxide of the alkaline earth metal. It is preferable. The amount of the metal acid salt is preferably 0.05 to 30 mol% based on the hydroxide and / or oxide of the alkaline earth metal.
[Selection figure] None

Description

  The present invention relates to a chemical heat storage material and a manufacturing method thereof, and a chemical heat pump and an operation method thereof.

  In recent years, the use of fossil fuels has been demanded by carbon dioxide emission regulations, and it is necessary to promote the use of exhaust heat in addition to energy saving in each process. As means for using exhaust heat, warm water storage at 100 ° C. or less using water is known. However, in hot water heat storage, (1) long-term heat storage is impossible due to heat dissipation loss, and (2) a large amount of water is required because the amount of sensible heat is small, making it difficult to make the heat storage equipment compact. (3) There is a problem that the output temperature is unsteady according to the usage amount and gradually drops. Therefore, it is necessary to develop a more efficient heat storage technology in order to promote consumer use of such waste heat.

  A chemical heat storage method is an example of a highly efficient heat storage technology. Since the chemical heat storage method involves chemical changes such as adsorption and hydration of substances, the amount of heat stored per unit mass is higher than the heat storage method using latent heat or sensible heat of the material itself (water, molten salt, etc.). As the chemical heat storage method, a water vapor adsorption / desorption method by adsorption / desorption of water vapor in the atmosphere, ammonia absorption to a metal salt (ammine complex formation reaction), a reaction by adsorption / desorption of an organic substance such as alcohol, and the like have been proposed. The water vapor adsorption / desorption method is most advantageous in view of environmental load and simplicity of the apparatus. As chemical heat storage materials used in the water vapor adsorption and desorption method, calcium hydroxide and magnesium hydroxide, which are alkaline earth metal hydroxides, are known.

  However, since these calcium hydroxide and magnesium hydroxide do not cause an effective dehydration reaction in a low temperature range of 100 to 400 ° C., there is a problem that they do not function as a practical heat storage material.

  In order to solve this problem, Patent Document 1 discloses that a composite hydroxide of magnesium and at least one metal component selected from the group consisting of nickel, cobalt, copper, and aluminum is used. A chemical heat storage material capable of storing heat at about ~ 300 ° C has been proposed.

  Furthermore, in Patent Document 2, for the purpose of improving the heat storage amount of the chemical heat storage material described in Patent Document 1, a chemical formed by adding a hygroscopic metal salt such as lithium chloride to a hydroxide of magnesium or calcium. Thermal storage materials have been proposed.

JP 2007-309561 A JP 2009-186119 A

  According to the techniques disclosed in Patent Documents 1 and 2, although the heat storage operating temperature can be lowered to some extent, for example, when trying to store the factory waste heat, the temperature range of the factory waste heat is 200 to 200. Since it is 250 ° C or lower temperature range, its heat storage operating temperature is not sufficiently low, it is difficult to efficiently use factory waste heat, and further reduction of operating temperature is required. It has been. From the aspect of improving the heat storage efficiency and expanding the application temperature range of the heat storage system, it is still important to improve the operating temperature of the chemical heat storage material.

  In view of the above situation, the present invention provides a chemical heat storage material that performs heat storage using dehydration reaction of an alkaline earth metal hydroxide, exhibits a higher reaction rate, and can realize heat storage at a lower temperature and An object of the present invention is to provide a manufacturing method thereof, a chemical heat pump for storing and radiating heat using the chemical heat storage material, and an operation method thereof.

  In order to solve the above-mentioned problems, the present inventors have made various studies. In producing a chemical heat storage material utilizing the dehydration reaction of an alkaline earth metal hydroxide, the alkaline earth metal hydroxide is produced. The present inventors have found that a chemical heat storage material containing a substance and / or oxide and a metal acid salt can produce a chemical heat storage material that exhibits a higher reaction rate and can realize heat storage at a lower temperature, and has led to the present invention.

  That is, the first aspect of the present invention relates to a chemical heat storage material containing an alkaline earth metal hydroxide and / or oxide and a metal acid salt.

  The second aspect of the present invention includes an alkaline earth metal hydroxide and / or oxide, an alkali metal compound, and a metal acid salt, and the amount of the alkali metal compound is the amount of the alkaline earth metal. It relates to a chemical heat storage material that is 0.1 to 50 mol% with respect to hydroxide and / or oxide, and further includes at least one specific metal selected from the group consisting of nickel, cobalt, copper, and aluminum The amount of the specific metal may include a compound, and the amount of the specific metal relates to a chemical heat storage material that is 0.1 to 40 mol% with respect to the hydroxide and / or oxide of the alkaline earth metal.

  The amount of the metal acid salt is preferably 0.05 to 30 mol% based on the hydroxide and / or oxide of the alkaline earth metal. The alkaline earth metal is preferably at least one selected from the group consisting of calcium, magnesium, strontium and barium, and the alkali metal is selected from the group consisting of lithium, potassium and sodium. It is preferable that it is at least one kind.

  Preferably, the metal acid salt is an acid salt of at least one metal selected from the group consisting of alkali metals and alkaline earth metals, and the metal acid salt is aluminum, iron, cobalt, It is preferably an acid salt of at least one metal selected from the group consisting of nickel, copper and zinc. The acid salt of at least one metal selected from the group consisting of the alkali metal and alkaline earth metal is at least one metal selected from the group consisting of lithium, sodium, potassium, calcium, magnesium, strontium and barium More preferably, the acid salt of

  3rd this invention is a manufacturing method of a chemical thermal storage material, Comprising: It is related with the manufacturing method including the process of mixing the hydroxide and / or oxide of an alkaline-earth metal, and the acid salt of a metal.

  The fourth aspect of the present invention is a method for producing a chemical heat storage material, comprising a step of mixing an alkaline earth metal hydroxide and / or oxide, an alkali metal compound, and a metal acid salt, The amount of the alkali metal compound relates to the production method, which is 0.1 to 50 mol% with respect to the hydroxide and / or oxide of the alkaline earth metal.

  In the manufacturing method, in the mixing step, a compound of at least one specific metal selected from the group consisting of nickel, cobalt, copper, and aluminum may be further mixed. It is related with the manufacturing method which is 0.1-40 mol% with respect to the hydroxide and / or oxide of an alkaline-earth metal.

  A fifth aspect of the present invention is a chemical heat pump using an endothermic dehydration reaction and a hydration exothermic reaction, which contains a chemical heat storage material containing an alkaline earth metal hydroxide and / or oxide, Heat supply means that is thermally connected to the reactor and supplies heat to the chemical heat storage material from the outside, and heat recovery means that is thermally connected to the reactor and extracts heat generated from the chemical heat storage material to the outside A chemical heat pump comprising: a water storage reservoir; a connection pipe for connecting the reactor and the reservoir to pass water; and a salt supply mechanism for supplying a metal acid salt into the chemical heat pump. About.

  The sixth aspect of the present invention is a method for operating the chemical heat pump, the step of supplying a metal acid salt to the chemical heat storage material accommodated in the reactor using the salt supply mechanism, A method of supplying heat to the chemical heat storage material through a heat supply means, and advancing an endothermic dehydration reaction of the chemical heat storage material to store heat. The method may further include a step of moving the water in the reservoir to the reactor, bringing the water into contact with the chemical heat storage material, and advancing a hydration exothermic reaction of the chemical heat storage material to dissipate heat.

  According to the present invention, in a chemical heat storage material that performs heat storage using dehydration reaction of an alkaline earth metal hydroxide, a chemical heat storage material that exhibits a higher reaction rate and can realize heat storage at a lower temperature and a method for manufacturing the same. Can be provided.

  In addition, according to the present invention, in a chemical heat pump for storing and radiating heat using a chemical heat storage material that performs heat storage using dehydration reaction of alkaline earth metal hydroxide, a higher reaction rate is exhibited, It is possible to provide a chemical heat pump capable of realizing heat storage at the same time and an operation method thereof.

The conceptual diagram which shows the structure of the chemical heat pump which concerns on one Embodiment of this invention. The graph which shows the time-dependent change of the reaction rate shown by Example 1 and Comparative Example 1 and 2 (a horizontal axis is the elapsed time (second) from the temperature rising start time, and a vertical axis is the reaction rate (%)). The graph which shows the time-dependent change of the reaction rate shown in Examples 2-8 and Comparative Examples 1 and 2 (the horizontal axis is the elapsed time (seconds) from the start of temperature increase, and the vertical axis is the reaction rate (%)). The graph which shows the time-dependent change of the reaction rate shown in Examples 9-12 and Comparative Examples 3 and 4 (the horizontal axis is the elapsed time (seconds) from the start of temperature increase, and the vertical axis is the reaction rate (%)).

Hereinafter, embodiments of the present invention will be described in detail.
The chemical heat storage material produced in the present invention utilizes the following reversible reaction with an alkaline earth metal hydroxide and oxide. In the following reaction formula, the case where calcium or magnesium is used as the alkaline earth metal is shown.
CaO + H ₂ O⇔Ca (OH) ₂ ΔH = −109.2 kJ / mol MgO + H ₂ O⇔Mg (OH) ₂ ΔH = −81.2 kJ / mol

  In each formula, the reaction in the right direction is a hydration exothermic reaction of calcium oxide or magnesium oxide. Conversely, the reaction in the left direction is a dehydration endothermic reaction of calcium hydroxide or magnesium hydroxide. That is, the chemical heat storage material of the present invention can store heat by the dehydration reaction of calcium hydroxide or magnesium hydroxide, and the hydrated reaction of calcium oxide or magnesium oxide proceeds to the stored thermal energy. Can be supplied by doing.

  The chemical heat storage material in the present invention only needs to contain either an alkaline earth metal hydroxide or an alkaline earth metal oxide, or may contain both. Examples of the alkaline earth metal include calcium, magnesium, strontium, and barium. One of these may be included, or a combination of two or more may be included. Among these, calcium and / or magnesium are preferable, and magnesium is more preferable. Alkaline earth metal hydroxide, alkaline earth metal oxide, preferably magnesium hydroxide, calcium hydroxide, magnesium-calcium composite hydroxide, magnesium oxide, calcium oxide, magnesium-calcium composite oxidation The thing is mentioned, These may be used independently and may mix and use 2 or more types.

  The present invention is characterized in that it constitutes a chemical heat storage material containing the alkaline earth metal hydroxide and / or oxide and a metal acid salt. The metal acid salt refers to a salt formed by reacting a metal compound with an acid, and particularly a salt formed by neutralizing a metal hydroxide with an acid. Specifically, for example, magnesium nitrate, magnesium acetate, magnesium benzoate, magnesium citrate, calcium nitrate, calcium acetate, calcium benzoate, calcium citrate, lithium nitrate, lithium acetate, lithium benzoate, lithium citrate, etc. For example, but not limited to.

  Examples of the metal constituting the metal acid salt include alkaline earth metals such as calcium, magnesium, strontium, and barium; alkali metals such as lithium, sodium, and potassium; aluminum, iron, cobalt, nickel, copper, and zinc. . One of these may be included, or a combination of two or more may be included. Among these, calcium, lithium and / or magnesium are preferable, and calcium and / or magnesium are more preferable. The alkaline earth metal constituting the acid salt of the premetal may be the same as or different from the alkaline earth metal constituting the hydroxide and / or oxide of the alkaline earth metal. However, the same thing is preferable from a viewpoint of the reaction rate improvement of a chemical heat storage material. However, when the metal acid salt used in the present invention is an alkaline earth metal acid salt, it is preferable not to use the alkaline earth metal carbonate and chloride as the alkaline earth metal acid salt. .

  It does not specifically limit as an acid which comprises the said metal acid salt, A well-known acid can be used suitably, Any of an inorganic acid and an organic acid may be sufficient. Further, it may be a water-soluble acid, or may be an acid that is hardly soluble or insoluble in water. Further, only one type may be used, or two or more types may be used in appropriate combination.

  Examples of the inorganic acid include hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, halogen oxoacid, sulfuric acid, nitric acid, phosphoric acid, phosphonic acid, sulfonic acid, boric acid, hydrocyanic acid, hexafluorophosphorus An acid etc. are mentioned.

  Examples of organic acids include organic sulfonic acids, organic phosphonic acids, aliphatic hydroxy acids (including dihydroxy acids and trihydroxy acids), aromatic hydroxy acids (including dihydroxy acids and trihydroxy acids), and aliphatic carboxylic acids ( Dicarboxylic acids and tricarboxylic acids), aliphatic unsaturated carboxylic acids (including dicarboxylic acids and tricarboxylic acids), aromatic carboxylic acids (including dicarboxylic acids and tricarboxylic acids), aromatic unsaturated carboxylic acids (dicarboxylic acids and tricarboxylic acids) Acid), other oxyacids, other oxocarboxylic acids, amino acids, and acids of these derivatives.

  Examples of the organic sulfonic acid include methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, and the like. Examples of organic phosphonic acids include phosphoric acid dimethyl ester and phenylphosphonic acid. Examples of the aliphatic hydroxy acid or aromatic hydroxy acid include lactic acid, malic acid, citric acid, and tartaric acid. Examples of aliphatic carboxylic acids or aliphatic unsaturated carboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, acrylic acid, sorbic acid, pyruvic acid, oxaloacetic acid, squaric acid, oxalic acid, malonic acid, succinic acid, glutar Acid, maleic acid, aconitic acid and the like can be mentioned. Examples of the aromatic carboxylic acid or aromatic unsaturated carboxylic acid include benzoic acid, phthalic acid, salicylic acid, shikimic acid, gallic acid, and pyromellitic acid. Examples of amino acids include aspartic acid and glutamic acid.

  The amount of the metal acid salt used is preferably 0.05 to 30 mol% when the amount of the alkaline earth metal hydroxide and / or oxide is 100 mol%. If the amount of the metal acid salt used is less than this, it is impossible to achieve a reaction rate improvement or a low heat storage temperature by the addition of the acid salt. In addition, when the amount of the metal acid salt used is larger than the above range, the influence of the alkaline earth metal hydroxide and / or oxide as the base material is large, and the unit volume or mass per unit mass of the chemical heat storage material is large. There is a risk that the amount of heat storage decreases. The amount of the metal acid salt used is preferably 0.1 to 20 mol%, more preferably 0.3 to 15 mol%, further preferably 0.5 to 10 mol%, and 0.8 to 8 mol%. Even more preferred is 1 to 6%.

  The chemical heat storage material of the present invention may further contain an alkali metal compound in addition to the alkaline earth metal hydroxide and / or oxide and the metal acid salt. By further blending an alkali metal compound, the reaction rate of the chemical heat storage material can be further increased.

  Examples of the alkali metal constituting the alkali metal compound include lithium, potassium, and sodium, and these may include only one kind, or may include two or more kinds in combination. Among these, lithium and sodium are preferable, and lithium is more preferable. The alkali metal compound is not particularly limited as long as it has the effect of the present invention, but is a hygroscopic salt that adsorbs moisture in the atmosphere or generates a corresponding hydrate. Salts that can be used are preferred. Examples of such salts include halides such as chlorides and bromides, hydroxides, carbonates, acetates, nitrates, and sulfates that can be easily handled. These may be used alone or in combination of two or more.

  More specifically, the lithium salt is preferably lithium halide and / or lithium hydroxide, more preferably lithium chloride, lithium bromide, and / or lithium hydroxide. The potassium salt is preferably potassium halide and / or potassium hydroxide, more preferably potassium chloride, potassium bromide and / or potassium hydroxide. As a salt of sodium, sodium halide and / or sodium hydroxide are preferable, and sodium chloride, sodium bromide, and / or sodium hydroxide are more preferable. However, the alkali metal compound and the metal acid salt are different compounds, and the case where the alkali metal compound and the metal acid salt indicate the same compound is not included in the present invention.

  The amount of the alkali metal compound used is 0.1 to 50 mol% when the amount of the alkaline earth metal hydroxide and / or oxide is 100 mol%. It is preferable that the amount is as follows. Accordingly, when the amount of the alkali metal compound is less than the above range, it becomes difficult to improve the reaction rate or lower the heat storage temperature by using the alkali metal compound. Moreover, when the amount of the alkali metal compound is larger than the above range, the heat storage amount per unit volume or unit mass by the chemical heat storage material may be reduced. The amount of the alkali metal compound is preferably 0.5 to 30 mol%, more preferably 1.0 to 20 mol%, and still more preferably 2.0 to 10 mol%. The dehydration endothermic temperature of the chemical heat storage material can be controlled by adjusting the amount of the alkali metal compound.

  The metal constituting the metal acid salt may be an alkali metal. For example, lithium chloride can be selected as the metal acid salt, lithium hydroxide can be selected as the alkali metal compound, and these can be used together. In this embodiment, the addition amount of these compounds can be adjusted within the scope of the present invention, but the molar ratio of the metal acid salt to the alkali metal compound with respect to the alkaline earth metal hydroxide and / or oxide. The total is preferably 0.1% or more and less than 50 mol%, and the molar ratio of the metal acid salt to the alkali metal compound is more preferably in the range of 1: 9 to 9: 1.

  The chemical heat storage material of the present invention may further contain a specific metal compound in addition to an alkaline earth metal hydroxide and / or oxide, an alkali metal compound, and a metal acid salt. By further including the specific metal compound, the reaction rate of the chemical heat storage material can be further increased. At this time, it is preferable that the compound of the specific metal is chemically complexed with an alkaline earth metal hydroxide and / or oxide.

  The specific metal is selected from the group consisting of nickel, cobalt, copper, and aluminum, and may include only one of these, or may include two or more in combination. Among these, at least 1 sort (s) selected from the group which consists of nickel, cobalt, and aluminum is preferable, and nickel and / or cobalt are more preferable.

  The compound of the specific metal is not particularly limited, but is preferably one that is complexed with an alkaline earth metal hydroxide and / or oxide, such as a halide such as chloride or bromide, a hydroxide, Examples thereof include oxides, carbonates, acetates, nitrates, and sulfates. These may be used alone or in combination of two or more. More specifically, nickel hydroxide, cobalt hydroxide, nickel-cobalt composite hydroxide, nickel oxide, cobalt oxide, and / or nickel-cobalt composite oxide are preferable.

  The amount of the specific metal compound used is such that the amount of the specific metal is 0.1 to 40 mol% when the amount of the hydroxide and / or oxide of the alkaline earth metal is 100 mol%. It is preferable that the amount is as follows. If the amount of the specific metal is reduced, it becomes difficult to achieve an improvement in the reaction rate or a reduction in the heat storage temperature by using the specific metal compound. Moreover, when the amount of the specific metal is larger than the above range, the heat storage amount per unit volume or unit mass by the chemical heat storage material may be reduced. 3-40 mol% is preferable, as for the quantity of the said specific metal, 5-30 mol% is more preferable, and 10-25 mol% is further more preferable. The dehydration endothermic temperature of the chemical heat storage material can be controlled by adjusting the amount of the specific metal compound used.

  The chemical heat storage material according to the present invention is simply a physical and hydroxide of an alkaline earth metal and / or oxide, a metal acid salt, an alkali metal compound, and in some cases a specific metal compound. However, the present invention is not limited to this. Some or all of each component may be chemically complexed with each other, and some or all of each component may chemically react with each other to form a third component. It may be a thing.

  The chemical heat storage material of the present invention is a chemical heat storage material utilizing an endothermic dehydration reaction and a hydration exothermic reaction with an alkaline earth metal hydroxide and an alkaline earth metal oxide. Within that range, the chemical heat storage material of the present invention may contain other components, including chemical heat storage components other than the constituent components described above and components that do not exhibit a chemical heat storage action (for example, binders). It may be.

  Although the shape of the chemical heat storage material of this invention is not specifically limited, For example, it may be shapes, such as powder, a granulated body, a molded object. In manufacturing a chemical heat storage material having a powder shape, a granulated body, or a molded body, a known method can be applied. For example, when producing a powdered chemical heat storage material, it is possible to apply sieving, crushing, and crushing processes. Moreover, when manufacturing the chemical heat storage material of a granulated body, granulation processes, such as extrusion granulation, rolling granulation, fluidized bed granulation, and spray drying, can be applied. When manufacturing the chemical heat storage material of a molded object, the molding process by press molding, injection molding, blow molding, vacuum molding, and extrusion molding can be applied. That is, as long as the properties as the chemical heat storage material are not impaired to the extent that they can be implemented, it is possible to select any shape according to the customer's embodiment.

Next, the method for producing the chemical heat storage material in the present invention will be described.
Although the method for producing the chemical heat storage material in the present invention is not particularly limited, as an example, first, an acid salt solution is dissolved in ion-exchanged water to prepare an acid salt aqueous solution, and an alkaline earth metal hydroxide is added thereto. Add and mix with stirring. Here, an alkali metal compound or an alkali metal compound and a specific metal compound may be added together. The obtained slurry can be dried to produce a chemical heat storage material as a dry powder. The method of stirring and mixing is not particularly limited as long as the ion-exchanged water as the solvent and the alkaline earth metal hydroxide powder are sufficiently mixed.

  The order of adding each component may be changed. In this case, for example, first, an alkali metal compound or an alkali metal compound and a specific metal compound are dissolved in ion-exchanged water, and an alkaline earth metal hydroxide powder is added to the slurry. After producing and subsequently adding a metal acid salt, it can be dried to produce a chemical heat storage material.

  Alternatively, instead of using the metal acid salt itself, a chemical heat storage material is produced by forming a metal acid salt by adding a metal and an acid under general conditions and reacting them in the chemical heat storage material manufacturing process. May be.

  The chemical heat storage material of the present invention can store heat by absorbing and dehydrating unused heat from a heat source of about 100 to 400 ° C., for example, factory waste heat. The dehydrated chemical heat storage material can easily maintain the heat storage state by keeping it in a dry state, and can be carried to a desired place while maintaining the heat storage state. In the case of heat dissipation, the heat of hydration reaction (optionally water vapor sorption heat) can be taken out as thermal energy by contacting with water, preferably water vapor. In addition, the water vapor sorption can be performed on one side in the hermetic chain space, and the other side can generate cold by evaporating water.

  The chemical heat storage material of the present invention is also suitable for effectively utilizing the heat of exhaust gas discharged from an engine, a fuel cell, or the like. For example, the heat of exhaust gas can be used for shortening the warm-up operation of an automobile, improving passenger amenity, improving fuel consumption, reducing exhaust gas damage by improving the activity of an exhaust gas catalyst, and the like. In particular, since the engine load is not constant and the exhaust output is unstable, the direct use of exhaust heat from the engine is inevitably inefficient and inconvenient. When the chemical heat storage material of the present invention is used, the exhaust heat from the engine is temporarily stored, and the heat is output according to the heat demand, so that more ideal exhaust heat can be used.

  The chemical heat storage material of the present invention can prevent or repair deterioration of its heat storage performance by appropriately replenishing a metal acid salt after repeating heat storage and heat dissipation a plurality of times. What is necessary is just to perform replenishment of the metal acid salt with respect to a thermal storage material, and the specific aspect is not specifically limited. After removing the chemical heat storage material from the chemical heat pump or the target system (for example, vehicle), the metal acid salt may be replenished, or the metal acid salt may be added to the chemical heat pump or target system at any time. By providing a mechanism for replenishing the chemical heat storage material, it is possible to replenish the metal acid salt while continuously operating the chemical heat pump or the target system without taking out the chemical heat storage material.

Next, an embodiment of a chemical heat pump using the chemical heat storage material of the present invention will be described.
FIG. 1 is a conceptual diagram showing a configuration of a chemical heat pump according to an embodiment of the present invention. The chemical heat pump 10 has a reactor 11 that contains a chemical heat storage material. The chemical heat storage material 21 accommodated in the reactor 11 is not particularly limited as long as it contains an alkaline earth metal hydroxide and / or oxide. The chemical heat storage material of the present invention may contain a metal acid salt in addition to the alkaline earth metal hydroxide and / or oxide, or may not contain a metal acid salt. There may be. Further, it may further contain an alkali metal compound, a specific metal compound or the like, or may not contain it. The chemical heat storage material 21 is preferably the chemical heat storage material of the present invention.

  The reactor 11 is thermally connected to heat supply means 12 for supplying heat from the outside such as factory waste heat to the chemical heat storage material in the reactor 11. Thereby, the dehydration reaction of the chemical heat storage material proceeds by supplying heat to the chemical heat storage material. That is, the alkaline earth metal hydroxide, which is a chemical heat storage material, releases water and is converted into an oxide, whereby heat storage by a chemical heat pump becomes possible.

  Next, by supplying water to the alkaline earth metal oxide generated by the endothermic dehydration reaction, the hydration exothermic reaction of the chemical heat storage material proceeds. That is, the oxide and water react to generate a hydroxide and generate heat. Thus, the heat recovery means 13 for taking out the heat generated from the chemical heat storage material to the outside is thermally connected to the reactor 11. The heat recovered from the chemical heat pump by the heat recovery means 13 can then be used effectively for any application. Further, the heat recovery means 13 may be configured integrally with the heat supply means 12 described above.

  The water released by the endothermic dehydration reaction from the chemical heat storage material in the reactor 11 or the water supplied to the chemical heat storage material to advance the hydration exothermic reaction is stored in the reservoir 14. The water 22 in the reservoir may be liquid water or water vapor. Although not shown, the reservoir 14 has a second heat supply means for heating the water in the reservoir and a second heat recovery means for taking out the heat of evaporation or condensation of the water to the outside. It may be provided.

  The reactor 11 and the reservoir 14 are connected by a connecting pipe 15 for passing the water. The water released from the chemical heat storage material in the reactor 11 during the dehydration reaction moves to the reservoir 14 through the connecting pipe 15, and the water stored in the reservoir 14 passes through the connecting pipe 15 to the reactor 11. And the hydration exothermic reaction can proceed. The movement of water may be performed by converting water into water vapor by heating or decompression, or may be performed by dropping the water by placing the reactor 11 and the reservoir 14 vertically. The connecting pipe 15 can be provided with an on-off valve 16 in order to interrupt the movement of water in a timely manner.

  The chemical heat pump of the present invention is provided with a salt supply mechanism for supplying a metal acid salt into the chemical heat pump. The salt supply mechanism includes at least an openable and closable salt supply port 17 provided on a wall surface of the connection pipe 15 or the like in order to supply a metal acid salt into the chemical heat pump system. The salt supply mechanism may further include a salt storage unit (not shown) for storing a metal acid salt. The salt storage unit is connected to the salt supply port 17.

  As the metal acid salt supplied from the salt supply port 17, the metal acid salt described above can be used. The metal acid salt may be supplied alone, or the metal acid salt may be mixed in an appropriate medium and supplied in the form of an aqueous solution, for example. Further, the metal acid salt may be supplied as a liquid or may be supplied in a powder form. It can also be supplied by spraying.

  The installation position of the salt supply port 17 is not particularly limited as long as the metal acid salt is supplied into the chemical heat pump so that the metal acid salt and the chemical heat storage material can contact each other. When the salt supply port 17 is provided in the connection pipe 15 as shown in FIG. 1, for example, when water is moving from the reservoir 14 to the reactor 11, the metal acid salt is transferred from the salt supply port 17. If it supplies in a chemical heat pump, the metal acid salt with water can be introduce | transduced into the reactor 11, and it can be made to contact the chemical heat storage material in the reactor 11. FIG. Further, the salt supply port 17 may be provided in the reactor 11 or in the reservoir 14.

  By supplying the metal acid salt into the chemical heat pump by the salt supply mechanism, the chemical heat storage material mainly composed of an alkaline earth metal hydroxide and / or oxide is brought into contact with the metal acid salt. As described with respect to one aspect of the present invention, it is possible to achieve a higher reaction rate and realize heat storage at a lower temperature. According to the chemical heat pump of the present invention, it is possible to replenish the chemical heat storage material accommodated in the chemical heat pump with a metal acid salt. Accordingly, it is possible to prevent or repair the deterioration of the heat storage performance of the chemical heat storage material after repeating heat storage and heat dissipation a plurality of times.

  Since the chemical heat storage material in the chemical heat pump can be supplemented with a metal acid salt, the chemical heat storage material stored in the chemical heat pump may be any material that contains an alkaline earth metal hydroxide and / or oxide. The metal acid salt may not be blended in advance. However, it is preferable that the chemical heat storage material stored in the chemical heat pump is premixed with a metal acid salt.

  The addition of the metal acid salt into the chemical heat pump may be performed only once or a plurality of times. In the present invention, in particular, when heat storage and heat dissipation of the chemical heat pump are repeatedly performed, when the reaction rate exhibited by the chemical heat storage material has decreased, by adding a metal acid salt, the reaction rate during heat storage of the chemical heat pump Can be expected to improve.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

(Evaluation method)
About the chemical heat storage material obtained by each Example and the comparative example, thermal evaluation was performed using the thermogravimetric / differential thermal analysis measuring device (TG / DTA6300, Seiko Instruments Inc. make). Specifically, the heating rate is 10 ° C./min. , Magnesium-based chemical heat storage material samples are heated to 300 ° C, calcium-based chemical heat storage material samples are heated to 400 ° C under atmospheric conditions and atmospheric pressure, and then the temperature is kept constant. The heat was measured. Based on the obtained weight loss value, the reaction rate was calculated as the rate at which magnesium hydroxide in each chemical heat storage material changed to magnesium oxide or the rate at which calcium hydroxide changed to calcium oxide.

  The reaction rate is calculated by setting the weight of the chemical heat storage material at the time when the temperature is raised to 200 ° C. to 0% as the starting weight in order to exclude the influence of volatile components and the like. Alternatively, the weight loss when assuming that all calcium hydroxide was changed to calcium oxide was determined with a reaction rate of 100%.

  The performance evaluation of the magnesium-based chemical heat storage material was performed based on the reaction rate calculated from the weight reduction value at the time when 4,000 seconds had elapsed from the start of temperature increase. That is, this evaluation method compares the reaction rate when the chemical heat storage material is held for a predetermined time at 300 ° C., which is a temperature at which thermal decomposition of magnesium hydroxide does not substantially proceed. The higher the reaction rate, the faster the endothermic dehydration reaction proceeds, indicating that the amount of heat storage is large and heat can be stored with lower temperature heat. In addition, the number of the relative reaction rate in a table | surface shows not a absolute value but a relative value when the reaction rate of each comparative example is set to 100 of the reference | standard.

  The performance evaluation of the calcium-based chemical heat storage material was performed based on the reaction rate calculated from the weight reduction value at the time when 3,000 seconds had elapsed from the start of temperature increase. That is, this evaluation method compares the reaction rate when the chemical heat storage material is held for a predetermined time at 400 ° C., which is a temperature at which the thermal decomposition of calcium hydroxide proceeds gradually. The higher the reaction rate, the faster the endothermic dehydration reaction proceeds, indicating that the amount of heat storage is large and heat can be stored with lower temperature heat. In addition, the number of the relative reaction rate in a table | surface shows not a absolute value but a relative value when the reaction rate of a comparative example is set to 100 of the reference | standard.

The magnesium hydroxide used in the examples and comparative examples was manufactured by the present inventors. The purity of magnesium hydroxide is calculated by converting Ca, Si, P, S, Fe, B, and Na, which are the main impurities, into oxides using a multi-element simultaneous X-ray fluorescence spectrometer (Simulix12, manufactured by Rigaku Corporation). Calculated by subtracting from 100%. The BET specific surface area was measured by a gas adsorption method (BET method) using nitrogen gas using a specific surface area measuring device (Macsorb, manufactured by Mounttech Co. Ltd.). The volume average particle diameter was measured using a laser diffraction / scattering particle size distribution measuring apparatus (MT3300 manufactured by Nikkiso Co., Ltd.).
The calcium hydroxide used in the examples and comparative examples was a commercially available reagent (manufactured by Kanto Chemical Co., Ltd., reagent special grade, purity 95%).

Example 1
5 g of magnesium hydroxide (purity 99% or more, BET specific surface area 8.4 m ² / g, volume average particle diameter 3.5 μm) was weighed, and further, 2.4 mol% of the amount of magnesium hydroxide. Magnesium acetate (Kanto Chemical Reagent, special grade) was weighed. The weighed magnesium acetate was completely dissolved in 50 mL of ion exchange water to obtain an aqueous magnesium acetate solution. The magnesium hydroxide weighed above was added to the magnesium acetate aqueous solution, and stirred with a magnetic stirrer for 300 seconds at a rotation speed of 60 (rpm) to prepare a slurry. The slurry was dried at 110 ° C. for 12 hours or more with a dryer (DRA430DA manufactured by Advantech Co., Ltd.) to remove moisture, thereby producing a chemical heat storage material. About the obtained chemical heat storage material, the thermal behavior was confirmed by the said evaluation method, and the reaction rate was computed.

(Comparative Example 1)
For magnesium hydroxide itself (purity 99% or more, BET specific surface area 8.4 m ² / g, volume average particle diameter 3.5 μm), the reaction rate was calculated in the same manner.

  Table 1 shows the numbers obtained by converting the reaction rate obtained in Example 1 into the relative reaction rate, with the reaction rate of the magnesium hydroxide alone obtained in Comparative Example 1 being 100 as a reference.

  FIG. 2 is a graph showing the change over time in the reaction rate shown in Example 1, Comparative Example 1, and Comparative Example 2 described later. The relative reaction rate shown in Table 1 is a relative value calculated based on the reaction rate at 4,000 seconds in the graph in FIG.

  The magnesium hydroxide simple substance of Comparative Example 1 to which no metal acid salt was added had a very low reaction rate under the evaluation conditions used here, and the endothermic dehydration reaction hardly proceeded. From Table 1 and FIG. 2, the chemical heat storage material of Example 1 manufactured by adding a metal acid salt to magnesium hydroxide has a reaction rate as compared with Comparative Example 1 under the same evaluation conditions as Comparative Example 1. It can be confirmed that the endothermic dehydration reaction is proceeding rapidly. From this, it can be seen that the chemical heat storage material of Example 1 has a larger amount of heat storage than the magnesium hydroxide simple substance of Comparative Example 1, and can store heat even at lower temperature.

  Furthermore, FIG. 2 shows that the reaction rate of Example 1 is much higher than the reaction rate of Comparative Example 2 described later in which only lithium hydroxide is blended with magnesium hydroxide. When the reaction rate at 4,000 seconds in Comparative Example 2 is set to 100 and the reaction rate at 4,000 seconds in Example 1 is converted into a relative reaction rate, 292 is calculated.

(Example 2)
Weigh 5 g of magnesium hydroxide, and weigh magnesium nitrate (Wako Pure Chemicals Reagent, Special Grade) in an amount of 2.4 mol% with respect to the magnesium hydroxide, and further 20 mol with respect to the magnesium hydroxide. % Of lithium hydroxide monohydrate (Kanto Chemical Reagent, special grade, purity 98.0%) was weighed. The weighed magnesium nitrate was completely dissolved in 50 mL of ion exchange water to obtain an aqueous magnesium nitrate solution. The magnesium hydroxide and lithium hydroxide monohydrate weighed above were added to the magnesium nitrate aqueous solution and stirred with a magnetic stirrer for 300 seconds at a rotation speed of 60 (rpm) to prepare a slurry. The slurry was dried at 110 ° C. for 12 hours or more with a dryer (Advantech Co., Ltd., DRA430DA) to remove moisture, thereby producing a chemical heat storage material. About the obtained chemical heat storage material, the thermal behavior was confirmed by the said evaluation method, and the reaction rate was computed.

(Example 3)
A chemical heat storage material was produced in the same manner as in Example 2 except that magnesium acetate (Kanto Chemical Reagent, Special Grade) was used instead of magnesium nitrate, and the reaction rate was similarly calculated.

Example 4
A chemical heat storage material was produced in the same manner as in Example 2 except that magnesium chloride (Kanto Chemical Reagent, Special Grade) was used instead of magnesium nitrate, and the reaction rate was similarly calculated.

(Example 5)
A chemical heat storage material was produced in the same manner as in Example 2 except that magnesium benzoate (Wako Pure Chemical Reagent, purity 95.0%) was used instead of magnesium nitrate, and the reaction rate was calculated in the same manner.

(Example 6)
The same method as in Example 2 except that magnesium citrate (Wako Pure Chemicals, Chemical) was used instead of magnesium nitrate and the amount thereof was adjusted to 0.8 mol% with respect to magnesium hydroxide. A chemical heat storage material was produced, and the reaction rate was calculated in the same manner.

(Example 7)
The same method as in Example 2 except that lithium chloride (Kanto Chemical Reagent, special grade, purity 99.0%) was used instead of magnesium nitrate and the amount thereof was adjusted to 10 mol% with respect to magnesium hydroxide. The chemical heat storage material was manufactured with the above, and the reaction rate was calculated in the same manner.

(Example 8)
A chemical heat storage material was produced in the same manner as in Example 2 except that lithium iodide (Wako Reagent reagent, grade 1) was used instead of magnesium nitrate, and the reaction rate was calculated in the same manner.

(Comparative Example 2)
A chemical heat storage material was produced in the same manner as in Example 2 except that magnesium hydroxide was added to 50 mL of ion-exchanged water instead of magnesium nitrate without using magnesium nitrate, and the reaction rate was calculated in the same manner. .

In Table 2, the reaction rate obtained in Comparative Example 2 in which a chemical heat storage material was produced without adding a metal acid salt was defined as 100, and the reaction rates obtained in Examples 2 to 8 were used as relative reaction rates. The numbers obtained by conversion are shown.
FIG. 3 is a graph showing changes over time in the reaction rates shown in Examples 2 to 8 and Comparative Example 2. In addition, the relative reaction rate shown in Table 2 is a relative value calculated based on the reaction rate at 4,000 seconds in the graph in FIG.

  From Table 2 and FIG. 3, the chemical heat storage materials of Examples 2 to 8 manufactured by adding metal acid salt together with lithium hydroxide, which is an alkali metal compound, to magnesium hydroxide, add metal acid salt. Compared with the chemical heat storage material of Comparative Example 2 manufactured without using, it can be confirmed that the reaction rate is significantly high and the endothermic dehydration reaction proceeds rapidly. From this, it can be seen that the chemical heat storage materials of Examples 2 to 8 can store heat even at lower temperatures than the chemical heat storage material of Comparative Example 2.

Example 9
5 g of calcium hydroxide (Kanto Chemical Co., Ltd., reagent grade, purity 95% or more) is weighed, and further, calcium nitrate tetrahydrate (Kanto Chemical Reagent, First grade) was weighed, and further lithium hydroxide monohydrate (Kanto Chemical Reagent, special grade, purity 98.0%) in an amount of 20 mol% with respect to the calcium hydroxide was weighed. The weighed calcium nitrate was completely dissolved in 50 mL of ion exchange water to obtain an aqueous calcium nitrate solution. The calcium hydroxide and lithium hydroxide monohydrate weighed above were added to the aqueous calcium nitrate solution, and stirred with a magnetic stirrer for 300 seconds at a rotational speed of 60 (rpm) to prepare a slurry. The slurry was dried at 110 ° C. for 12 hours or more with a dryer (DRA430DA manufactured by Advantech Co., Ltd.) to remove moisture, thereby producing a chemical heat storage material. About the obtained chemical heat storage material, the thermal behavior was confirmed by the said evaluation method, and the reaction rate was computed.

(Example 10)
A chemical heat storage material was produced in the same manner as in Example 9 except that calcium chloride (Kanto Chemical Reagent, Special Grade) was used instead of calcium nitrate, and the reaction rate was similarly calculated.

(Example 11)
A chemical heat storage material was produced in the same manner as in Example 9 except that lithium nitrate (Wako Pure Chemical Industries, special grade) was used instead of calcium nitrate, and the reaction rate was calculated in the same manner.

(Example 12)
A chemical heat storage material was produced in the same manner as in Example 9 except that lithium chloride (Kanto Chemical Reagent, Special Grade) was used instead of calcium nitrate, and the reaction rate was similarly calculated.

(Comparative Example 3)
Without using calcium nitrate, a chemical heat storage material was produced in the same manner as in Example 9 except that calcium hydroxide was added to 50 mL of ion exchange water instead of calcium nitrate aqueous solution, and the reaction rate was calculated in the same manner. .

(Comparative Example 4)
The reaction rate was calculated in the same manner for calcium hydroxide itself (Kanto Chemical Co., Ltd., reagent grade, purity 95% or more).

In Table 3, the reaction rate obtained in Comparative Example 3 in which a chemical heat storage material was produced without addition of acid was taken as 100, and the reaction rates obtained in Examples 9 to 12 and Comparative Example 4 were used as relative reaction rates. The numbers obtained by converting to are shown.
FIG. 4 is a graph showing the change over time of the reaction rates shown in Examples 9 to 12 and Comparative Examples 3 and 4. In addition, the relative reaction rate shown in Table 3 is a relative value calculated based on the reaction rate at 3,000 seconds in the graph in FIG.

  From Table 3 and FIG. 4, the chemical heat storage materials of Examples 9 to 12 manufactured by adding metal acid salt were compared with the chemical heat storage material of Comparative Example 3 manufactured without adding metal acid salt. Compared with the calcium hydroxide simple substance of Example 4, it can be confirmed that the reaction rate is significantly high and the endothermic dehydration reaction proceeds rapidly. From this, the chemical heat storage materials of Examples 9 to 12 have a lower temperature than the chemical heat storage material of Comparative Example 3 manufactured without adding the metal acid salt and the calcium hydroxide alone of Comparative Example 4. It can be seen that heat can be stored even with heat.

DESCRIPTION OF SYMBOLS 10 Chemical heat pump 11 Reactor 12 Heat supply means 13 Heat recovery means 14 Reservoir 15 Connection pipe 16 On-off valve 17 Salt supply port 21 Chemical heat storage material 22 Water

Claims (21)

Comprising a hydroxide and / or oxide of an alkaline earth metal, a metal salt,
The acid constituting the metal acid salt is selected from the group consisting of organic acids, halogen oxoacids, sulfuric acid, nitric acid, phosphoric acid, phosphonic acid, sulfonic acid, boric acid, hydrocyanic acid, and hexafluorophosphoric acid. A chemical heat storage material that is at least one kind . An alkaline earth metal hydroxide and / or oxide, an alkali metal compound, and a metal acid salt;
The chemical heat storage material, wherein the amount of the alkali metal compound is 0.1 to 50 mol% with respect to the hydroxide and / or oxide of the alkaline earth metal. And further comprising a compound of at least one metal selected from the group consisting of nickel, cobalt, copper and aluminum,
The amount of the said metal is a chemical heat storage material of Claim 1 or 2 which is 0.1-40 mol% with respect to the hydroxide and / or oxide of the said alkaline-earth metal.   The amount of the said metal acid salt is a chemical heat storage material in any one of Claims 1-3 which is 0.05-30 mol% with respect to the hydroxide and / or oxide of the said alkaline-earth metal. .   The chemical heat storage material according to any one of claims 1 to 4, wherein the alkaline earth metal is at least one selected from the group consisting of calcium, magnesium, strontium, and barium.   The chemical heat storage material according to any one of claims 2 to 5, wherein the alkali metal is at least one selected from the group consisting of lithium, potassium, and sodium.   The chemical heat storage material according to any one of claims 1 to 6, wherein the metal acid salt is at least one metal acid salt selected from the group consisting of alkali metals and alkaline earth metals.   The chemical heat storage material according to any one of claims 1 to 6, wherein the metal acid salt is an acid salt of at least one metal selected from the group consisting of aluminum, iron, cobalt, nickel, copper, and zinc. .   The acid salt of at least one metal selected from the group consisting of the alkali metal and alkaline earth metal is at least one metal selected from the group consisting of lithium, sodium, potassium, calcium, magnesium, strontium and barium The chemical heat storage material according to claim 7, which is an acid salt. A method for producing a chemical heat storage material,
Comprises the step of mixing a hydroxide and / or oxide of an alkaline earth metal, a metal salt,
The acid constituting the metal acid salt is selected from the group consisting of organic acids, halogen oxoacids, sulfuric acid, nitric acid, phosphoric acid, phosphonic acid, sulfonic acid, boric acid, hydrocyanic acid, and hexafluorophosphoric acid. A manufacturing method which is at least one kind . A method for producing a chemical heat storage material,
Mixing an alkaline earth metal hydroxide and / or oxide, an alkali metal compound, and a metal acid salt;
The amount of the alkali metal compound is 0.1 to 50 mol% with respect to the alkaline earth metal hydroxide and / or oxide. In the mixing step, a compound of at least one metal selected from the group consisting of nickel, cobalt, copper and aluminum is further mixed,
The amount of the said metal is a manufacturing method of Claim 10 or 11 which is 0.1-40 mol% with respect to the hydroxide and / or oxide of the said alkaline-earth metal.   The manufacturing method according to any one of claims 10 to 12, wherein the amount of the metal acid salt is 0.05 to 30 mol% with respect to the hydroxide and / or oxide of the alkaline earth metal.   The manufacturing method according to any one of claims 10 to 13, wherein the alkaline earth metal is at least one selected from the group consisting of calcium, magnesium, strontium, and barium. The manufacturing method according to any one of claims 11 to 14, wherein the alkali metal is at least one selected from the group consisting of lithium, potassium, and sodium.   The manufacturing method according to any one of claims 10 to 15, wherein the metal acid salt is an acid salt of at least one metal selected from the group consisting of alkali metals and alkaline earth metals.   The manufacturing method according to any one of claims 10 to 15, wherein the metal acid salt is an acid salt of at least one metal selected from the group consisting of aluminum, iron, cobalt, nickel, copper, and zinc.   The acid salt of at least one metal selected from the group consisting of the alkali metal and alkaline earth metal is at least one metal selected from the group consisting of lithium, sodium, potassium, calcium, magnesium, strontium and barium The manufacturing method of Claim 16 which is an acid salt of. A chemical heat pump using an endothermic dehydration reaction and a hydration exothermic reaction,
A reactor containing a chemical heat storage material comprising an alkaline earth metal hydroxide and / or oxide;
Heat supply means thermally connected to the reactor and supplying heat to the chemical heat storage material from the outside;
A heat recovery means that is thermally connected to the reactor and extracts heat generated from the chemical heat storage material to the outside;
A reservoir for storing water;
A connecting pipe for connecting the reactor and the reservoir and passing water;
And a salt supply mechanism for supplying a metal acid salt into the chemical heat pump. A method of operating a chemical heat pump according to claim 19,
Supplying a metal acid salt to the chemical heat storage material housed in the reactor using the salt supply mechanism;
Supplying heat to the chemical heat storage material through the heat supply means, and advancing an endothermic dehydration reaction of the chemical heat storage material to store heat.   21. The method according to claim 20, further comprising the step of transferring water in the reservoir to the reactor to contact the chemical heat storage material and advancing a hydration exothermic reaction of the chemical heat storage material to dissipate heat.

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