WO2016006768A1 - Heat storage material for storing hydration heat energy, and preparation method therefor - Google Patents

Abstract

A heat storage material of the present invention comprises a porous support and a salt impregnated into the porous support, the hydration heat energy is stored in the heat storage material, and a preparation method therefor comprises the steps of: preparing a salt solution by mixing a salt and a solvent; impregnating the salt into the porous support by dipping the porous support in the salt solution; and drying the salt-impregnated porous support. A prepared heat storage material has high material transfer and heat transfer efficiency and can be environmentally friendly by enabling the semi-permanent use thereof.

Description

Heat storage material for hydration heat energy storage and manufacturing method thereof

The present invention relates to a method of using the heat of hydration energy, and relates to a heat storage material and a method for producing the same, the reaction heat is stored semi-permanently by impregnating a salt in the porous carrier, is semi-permanently regenerated.

For indoor heating, most of them use heat supply of hot water supplied with heating plumbing facilities and radiators, combustion heat of fossil fuels such as coal, oil, and gas, or electricity as a heating device. Recently, oil prices have continued to soar, and oil prices are not expected to decline in the future, and limited resources are directly linked to environmental issues that are already attracting considerable attention. In this regard, it is necessary to develop a device using alternative fuels or a high efficiency heating device.

In addition, as a small auxiliary heating method, a hand stove, a hot pack, etc. are used, but a small capacity and a product that cannot be recycled after one use (products using a mixture of iron powder, activated carbon, sodium chloride, etc.). When used and discarded for single use, the waste disposal is also a problem, costly loss, and hot packs are recyclable, but the liquid state is inconvenient to handle and undesired due to shock during storage and transport. There is a drawback to time. In addition, there is a disadvantage that the efficiency is low due to the small amount of heat generated using only the heat of solidification of the contents.

Furthermore, even in the case of exothermic heat using a specific chemical reaction, the calorific value is very large and generates heat of 400 ° C. or higher, which makes it unsuitable for heating, and in order to use such high temperature, water or other heat conductors are used as heat transfer mediums. The efficiency is low, there is a disadvantage that additional devices, etc. are required.

In order to solve this disadvantage, there is a method using the heat of hydration generated from the hydration reaction using a salt that forms a hydrate. For example, salts that form hydrates such as magnesium chloride generate heat of hydration in the process of forming a hydrate in anhydrous state. By using the characteristics of these salts, the moisture contained in the salt is removed, sealed and stored with solar heat or waste heat generated from factories, etc., and then heat can be obtained by adding moisture at a necessary time and a necessary place later. In particular, in the case of the use of solar heat, it can provide a lot of possibilities in the use of energy, such as being able to store the solar heat in the summer to use in the winter.

However, there are several limitations to the use of these salts. First of all, these salts have the property of absorbing moisture in the air, so in order to store heat for a long time and use it at the proper time, it must be stored in a closed space that is blocked from the outside to proceed with dehydration and hydration.

In addition, these salts bind to each other in the process of dehydration and hydration to agglomerate into large chunks, so that heat transfer and mass transfer are very disadvantageous, which is a great obstacle to dehydration and hydration, that is, to store heat and use stored heat.

In addition, the salt covering the heat transfer interface during the dehydration is accompanied by a local overheating phenomenon, resulting in a problem that the salt is pyrolyzed due to excessively high temperature. For example, in the case of magnesium chloride, when the dehydration temperature is higher than 120 ℃ decomposes and discharges hydrogen chloride gas, in addition to the problem that the salt is gradually lost, the problem of corrosion by hydrogen chloride gas is raised.

Therefore, in order to use such a salt as a heat storage medium, it is necessary to make the interface large enough so that the material (eg, moisture) and heat can move without great resistance.

An object of the present invention is to regenerate the salt by impregnating the salt in the porous carrier in the use of heat of hydration energy, to remove the salt agglomeration phenomenon, to prevent thermal decomposition problems of the salt due to local overheating phenomenon and to increase the interface of the material transfer and heat transfer and its To provide a manufacturing method.

The heat storage material according to an embodiment of the present invention is a porous carrier; And a salt impregnated in the porous carrier, wherein the heat of hydration energy is stored.

The porous carrier may be any one selected from the group consisting of pearlite, zeolite, activated carbon, and a combination thereof.

The porous carrier may have a specific surface area of 0.001 to 10.0 m ² / g.

The salt may be any one selected from the group consisting of metal chloride salts, metal sulfate salts, metal nitrate salts, and combinations thereof.

The heat storage material may generate a heat of hydration by humidification, thereby lowering the stored heat of hydration energy.

Lower hydration heat energy of the heat storage material can be recovered by heating dehydration.

The heat dehydration reaction may be performed by any one heat selected from the group consisting of solar heat, waste heat, and a combination thereof.

The heat storage material may have an average apparent diameter of 0.5 mm to 50 mm.

The heat storage material may be a calorific value of 700 to 1700 MJ / m ³ per unit volume due to humidification.

The heat storage material may be any one type selected from the group consisting of blocks, honeycombs, and combinations thereof.

Method for producing a heat storage material according to another embodiment of the present invention, preparing a salt solution by mixing a salt and a solvent; Supporting the porous carrier in the salt solution, so that the salt is impregnated into the porous carrier; And drying the salt-impregnated porous carrier, wherein the heat storage material stores hydration heat energy.

The solvent may have a boiling point of 130 ° C. or less.

The concentration of the salt solution may be 50% to 80%.

The drying may be dried by any one selected from the group consisting of heat drying, hot air drying, natural drying, vacuum drying and combinations thereof.

The drying may be performed at a temperature condition of 50 to 250 ℃.

In the present invention, it is intended to provide a heat storage material and a manufacturing method thereof in which hydration heat energy is stored, and the present invention will be described in more detail below.

The heat storage material according to an embodiment of the present invention, a porous carrier and a salt impregnated in the porous carrier, the heat storage material is that the heat of hydration energy is stored.

The salt may be any one selected from the group consisting of metal chloride salts, metal sulfate salts, metal nitrate salts, and combinations thereof. For example, magnesium chloride, calcium chloride, zinc chloride, aluminum chloride, and the like may be applied to the metal chloride, and the metal sulfate may be applied to magnesium sulfate, calcium sulfate, zinc sulfate, aluminum sulfate, and the like. Aluminum, calcium nitrate, magnesium nitrate, zinc nitrate and the like can be applied.

The salt may preferably be magnesium chloride or calcium chloride, and the application of magnesium chloride or calcium chloride as the salt may increase the calorific value of the heat storage material, but is not limited thereto. Zeolite or silica gel may also be applied as the salt.

The porous carrier may be applied without limitation as long as the pores are sufficient to increase the reaction interface, and for example, pearlite, zeolite, activated carbon, or a mixture thereof may be applied.

The porous carrier may have a specific surface area of 0.001 to 10.0 m ² / g, preferably 0.5 to 10.0 m ² / g, and when the specific surface area is less than 0.001 m ² / g, the reaction interface may not be sufficient to transfer materials and heat. This may not be smooth, and when the specific surface area exceeds 10.0 m ² / g, when applied to the reactor or the like, the path formation of the wet air may not be made smoothly, the strength of the heat storage material can be reduced.

In this way, by impregnating the salt into the porous carrier, it is possible to prevent agglomeration of large salts during dehydration and hydration of the salt, and to prevent local overheating caused by large reduction of the reaction interface. This can prevent the problem of pyrolysis of salts, thereby preventing the emission of toxic gases and the loss of salts. In addition, there is no self-aggregation phenomenon due to moisture absorption in the air can be stored for a long time, can be easily restored to anhydrous state by heating dehydration can be stored in an unsealed space.

Hydration heat energy stored in the heat storage material may be understood as an ability to generate heat of hydration, that is, a heat generation potential, and the heat generation potential has a maximum value when the heat storage material is dry. The impregnated salt may have a minimum when it is hydrated as much as possible by humidification, for example when it becomes hexahydrate in the case of magnesium chloride.

When the hydration reaction proceeds by humidification, the heat storage material may participate as a reactant to generate heat of hydration, thereby lowering the heat of hydration energy stored in the heat storage material. At this time, the heat amount that can be generated by the heat storage material, that is, the calorific value may be 700 to 1700 MJ / m ³ per unit volume of the heat storage material, but the heat amount that the heat storage material can generate is not limited to this range. The amount of heat that can be generated may vary depending on the application or size.

This may be a low value compared to general fossil fuels, but the heat storage material has no discharge of harmful substances such as fossil fuels, may be recycled semi-permanently rather than once, and may be manufactured in a simple manner.

Semi-permanent regeneration of the heat storage material, the heat of hydration lowered by heat dehydration can be recovered. By dehydrating the regenerated heat storage material by the hydration reaction to restore anhydrous state, that is, the heat generation potential of hydration to the initial state, the process of consuming and recovering such heat of hydration energy can be carried out semi-permanently.

The heating dehydration performed at this time may be performed by solar heat, waste heat or a combination thereof. Hydration heat energy can be used to recover hydration heat energy with strong solar heat in summer, and can be used in winter, and hydration heat energy as waste heat such as hot air or steam generated after heat exchange in plant such as manufacturing plant or power plant Can recover. Since the surplus energy is also used to recover the hydration heat energy of the heat storage material, the heat storage material may be more environmentally friendly than fossil fuels.

The heat storage material may have an average apparent diameter of 0.5 mm to 50 mm, preferably 0.5 to 20 mm. When the average apparent diameter of the heat storage material exceeds 50 mm, when applied to a heating device or a reactor, it may not be possible to secure a sufficient reaction interface in the space where the hydration reaction occurs, thereby reducing the amount of heat of hydration and efficiency. In addition, when the average apparent diameter is less than 0.5 mm, when applied to a heating device or a reactor, the air permeability may not be secured so that the passage path of water may not be smoothly formed.

However, in the case of a heat generating device such as a large-capacity heater that is used by filling a large amount of heat storage material, there may be an exceptional case of using a heat storage material having a size larger than 50 mm to maintain the strength of the heat storage material.

In addition, the shape of the heat storage material particles is irregular, each particle may have a different shape, and may not be a standard form such as spherical or hexahedral. Since the heat storage material particles have an irregular shape, when applied to a heating device or a reactor, the contact area with moisture such as wet air, that is, the reaction interface can be greatly increased.

The heating device to which the heat storage material may be applied may be, for example, an air heater, and the air heater may include a reaction part including a heating material in contact with moisture to cause a hydration reaction to be blocked from the outside; And a supply part connected to the reaction part and supplying a fluid containing water to the reaction part, wherein the heat storage material may be applied as a heating material of a heater.

The reaction part of the heater includes two or more sub-reaction parts separated from each other and blocked from the outside, and each of the sub-reaction parts includes a heating material, and the supply part is connected to the sub-reaction parts to connect the respective sub-reaction parts. It may include a sub-supply unit for supplying a fluid to.

Since the reaction part in the heater includes two or more sub-reaction parts, a plurality of reaction parts for generating a hydration reaction by the exothermic material may increase the temperature of a predetermined space or maintain the heating for a long time.

The material forming the outer surface of the reaction part, or the material forming the partition or outer surface of the sub-reaction parts may be a flexible material. Material such as the reaction unit can be selectively applied according to the use of the heater, it may be preferable to use a flexible material in the case of the thermal mat and hot pack, and when used as a heater to heat the air to heat the space It may be desirable to use a rigid material in terms of storage, movement, care and the like.

The heater may further include a discharge part connected to the reaction part, and the discharge part may be a discharge of the warm air warmed by the heating heat inside the reaction part. The outlet of the heater may be selectively included or not included depending on the use of the heater.

That is, when used for applications such as hot packs or thermal mats, the reaction part may be manufactured to an appropriate size in consideration of volume expansion, and the discharge part may be removed to fill the inner empty space with hot air to heat the air by heating the space. When used as a heater may be used to include a discharge so that the heated air can be immediately discharged to the outside.

In addition, in the case where the heater or the supply unit is a heater including two or more sub-reactors or sub-supply units, the discharge unit may also include a sub-discharge unit corresponding to each.

The heat storage material may also be applied to a heating method using air, wherein the heating method uses the above-described heater, and the fluid containing moisture introduced into the reaction part contacts the heating element to cause a hydration reaction, and the hydration It may include a heating step of heating the air in the reaction unit using the heating heat containing the heat of hydration generated in the process of changing the heat generating material into a hydrate by the reaction, and transfers heat to the outside of the heater using the heated air. .

The heat storage material according to an embodiment of the present invention may be applied as the heating material, and the fluid flowing into the reaction part may further use sprayed water or condensation heat in the form of droplets to increase reaction speed and induce a uniform reaction. It may be air containing water vapor to.

As such, the amount of water vapor included in the air may be 60% by weight relative to the total air, that is, relative humidity is about 60% or more, and 70% or more may be more preferable in order to further maximize heating efficiency by providing water as a source of moisture. have.

The heating method using the air may further include a wet air generation step before the heating step or at the same time as the heating step. The wet air generation step may be a step of evaporating water to water vapor and transferring the water vapor to the reaction unit through the supply unit.

By further adding a wet air generation step, it is possible to lower the dependence of the ambient air on the humidity in the heating method using the air can be a means for ensuring the performance of the heater used in the heating method.

Various methods may be used as the method of evaporating water with steam in the wet air generation step, for example, there may be a vacuum evaporation method, an evaporation method by heating, and the vacuum evaporation method may be appropriate in the present invention. have. That is, the water is evaporated to water vapor through a pressure drop using a vacuum pump, and the generated water vapor may be delivered to the reaction part through the supply part to which the fluid connected to the vacuum pump is supplied.

The heating method using the air may further include a drying step and a storage step after the heating step. The drying step may be a step of drying the hydrate of the heating material to regenerate the heating material.

The heating method using the air, after such a storage step, returns to the heating step again to cause a hydration reaction of the heating material, and to transfer heat to the outside of the heater through the discharge unit or with the air warmed in the reaction unit. It may be reused in the manner used for heating.

Since the heating method can be applied semi-permanently through the circulation method of heating, drying and storage, energy can be greatly reduced, and environmental pollution problems and resource shortages using only heating materials and water without using fossil fuels. It can be said to be a heating method that can actively cope with problems.

The heat storage material is not limited to being applied to the air heater or the heating method using air, but by applying the heat storage material of the present invention, the efficiency of the heater or heating method can be further maximized, and salt is used as a heat generating material. It can be more useful because it can solve all the problems that occur when.

Method for producing a heat storage material according to another embodiment of the present invention comprises the steps of preparing a salt solution by mixing a salt and a solvent; Supporting the porous carrier in the salt solution, so that the salt is impregnated into the porous carrier; And drying the salt-impregnated porous carrier. The heat storage material may be one in which hydration heat energy is stored.

Description of the salt, the porous carrier, the heat storage material and the heat of hydration energy is duplicated as described above, so the description thereof is omitted.

The solvent may have a boiling point of 130 ° C. or less. In order to evaporate the solvent at a temperature lower than the pyrolysis temperature of the salt during drying, any solvent that can be evaporated at 130 ° C. or lower is applicable. For example, water such as distilled water or deionized water, alcohol such as methanol or ethanol, etc. This can be applied.

In the step of preparing the salt solution, the concentration of the salt solution may be 50% to 80% saturated aqueous solution. The concentration range may be the concentration of the salt for the salt is sufficiently impregnated in the supported porous carrier. Low concentrations of the salt solution can reduce the amount of salts impregnated in the same amount of porous carrier, thereby reducing the calorific value, and the amount of heat required to evaporate the water contained in the salt solution increases the overall energy efficiency. Can be degraded.

The drying may be dried by, for example, heat drying, hot air drying, natural drying, vacuum drying, or a combination thereof. As long as it is possible to vaporize the solvent to make the heat storage material anhydrous, it can be applied without particular limitation.

The drying may be carried out at a temperature condition of 50 to 250 ℃, preferably 50 to 150 ℃. If the drying temperature is lower than 50 ℃, the time required for drying may be considerable, may be inefficient, the heat storage material may not be uniformly dried, if the drying temperature is higher than 250 ℃, the salt may be pyrolyzed and energy consumption Too much can be uneconomical. That is, in terms of improving energy use efficiency, it may be desirable to dry at the lowest possible temperature if it can be sufficiently heated.

The heat storage material of the present invention can prevent the salt agglomeration that can occur during the hydration reaction to prevent thermal decomposition and loss of the salt due to local overheating, the reaction interface is increased due to the salt is impregnated into the porous carrier material transfer and heat transfer The efficiency can be increased, and can be prepared by a simple method such as being supported in a salt solution, and can be used by semi-permanently regenerating has the advantage of being environmentally friendly.

Thus, when using the heat storage material of the present invention instead of using a salt in the heater or heating method, the efficiency can be increased, it can solve the existing problem.

1 is a schematic view showing a method of manufacturing a heat storage material according to an embodiment of the present invention.

Figure 2 schematically shows a heat storage material according to an embodiment of the present invention.

Figure 3 is a schematic diagram showing the movement path of the wet air in the salt powder and the heat storage material according to an embodiment of the present invention.

Figure 4 is a schematic diagram showing a case where the salt powder and the heat storage material according to an embodiment of the present invention is filled in the reactor.

5 is a graph showing a change in temperature over time of the hydration reaction of the salt powder (TC2) and the heat storage material (TC1) according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

Preparation Example: Production of Heat Storage Material

An embodiment of manufacturing the heat storage material will be described with reference to FIG. 1.

First, calcium chloride anhydride (CaCl ₂ Anhydrous) was prepared as distilled water and salt powder as a solvent. 200 g of the distilled water and 600 g of the calcium chloride anhydride were mixed to prepare an aqueous salt solution having a concentration of 75% as shown in the second state of FIG. 1.

Next, perlite was prepared as a porous carrier, and it was supported in the aqueous salt solution as in the third state of FIG. 1. Thereafter, the salt aqueous solution was heated to about 100 ° C. to evaporate all of the water, and the salt impregnated in pearlite was made anhydrous using a hot air of about 120 ° C. to prepare a heat storage material as in the fourth state of FIG. 1. .

2 and 3, due to the irregular shape of the pearlite it can be seen that the area that can be in contact with moisture, including wet air is considerably wider than the general salt powder, the salt impregnated in the pearlite of irregular shape compared to the aggregated salt powder In some cases, the formation of the path of the wet air is smooth and excellent in breathability, it can be seen that more favorable to the hydration reaction and can induce a uniform reaction.

Example: Hydration Reaction Using Heat Storage Material

As the heat generating material, the heat storage material prepared in Preparation Example was introduced into the reactor. A temperature of about 30 ° C. and air containing about 70% of water vapor were added thereto to induce hydration of the heat storage material. The water provided for the hydration was about 70 g. The temperature of the air in the reactor rises from the time point at which the wet air is provided in the reactor and the temperature is maintained, and the results are shown in Table 1 and FIG. 5.

Comparative Example: CaCl ₂  Hydration Reaction with Anhydride

The hydration reaction was induced in the same manner as in the above example except that 600 g of CaCl ₂ anhydride was added to the reactor as a heating material. The temperature of the air in the reactor rises from the time point at which the wet air is provided in the reactor and the temperature is maintained, and the results are shown in Table 1 and FIG. 5.

Table 1 Temperature rise Time to reach maximum temperature Temperature retention time Example (heat storage material) 40 ℃ or more 10 minutes 70 mins Comparative Example (CaCl ₂ Anhydride) 11 ℃ or more 15 mins 60 mins

Referring to Table 1 and FIG. 5, in the case of Comparative Example (TC2), after 15 minutes, the temperature in the reactor was increased by about 11 ° C., and thus the elevated temperature was maintained for about 60 minutes or more. In the case of TC1), the temperature in the reactor was increased by about 40 ° C. or more within 10 minutes, and thus the elevated temperature was maintained at about 32 ° C. or more for about 70 minutes or more. Through this, when using the heat storage material as a heat generating material, it can be confirmed that the heating efficiency is increased.

As such, when the heat storage material is used, the time taken to reach the maximum temperature is shorter, and the maximum temperature increase is also larger. As shown in FIG. 4, the heat storage material has better air permeability than the general salt particles. It can be confirmed that it is because of the size.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (8)

Porous carriers; And a salt impregnated in the porous carrier. The method of claim 1, The porous carrier has a specific surface area of 0.001 to 10.0 m ² / g heat storage material. The method of claim 1, The salt is a heat storage material is any one selected from the group consisting of metal chloride salts, metal sulfate salts, metal nitrate salts and combinations thereof. The method of claim 1, The heat storage material is a heat storage material is generated by the hydration heat is lowered by the hydration heat energy is stored. The method of claim 4, wherein Lower heat of hydration energy of the heat storage material is recovered by heating dehydration. The method of claim 5, The heat dehydration reaction is heat storage material is carried out by any one heat selected from the group consisting of solar heat, waste heat and combinations thereof. The method of claim 1, The heat storage material is a heat storage material comprising an average apparent diameter of 0.5 mm to 50 mm. The method of claim 1, The heat storage material is any one selected from the group consisting of blocks, honeycombs and combinations thereof.

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