JPS62213689A - Chemical heat-accumulating capsule - Google Patents

Abstract

PURPOSE:To prevent the carry-out of chemical heat-accumulating agent due to powdering as well as the clogging and solidifying of a heat resistant pourous body and permit to reuse it repeatedly by a method wherein the cylindrical body of the heat resistant porous body is filled with the powdered chemical heat accumulating agent. CONSTITUTION:A chemical heat-accumulating capsule 1 is prepared by a method wherein the cylindrical body 3 of heat resistant porous body is filled with chemical heat-accumulating agent 2, thereafter, both ends of the cylindrical body are sealed by employing the tubular plug of heat resistant porous body, provided with a fine hole diameter the same as or less than the hole diameter of the cylindrical body 3 of the heat resistant porous body, and inorganic binding agent such as clay, kaoline, ceramic cement or the like. This operation may be effected by forming previously a cylindrical body, whose one end is sealed previously or only one end is opened previously, and the chemical heat-accumulating agent 2 is loaded into the cylindrical body, thereafter, remaining one end may be sealed. In the chemical heat- accumulating capsule obtained in such a manner, the chemical heat-accumulating agent 2 will never be discharged to the outside of the cylindrical body and the capsule may be handled easily without handling the powdered body directly after sealing it. When the chemical heat- accumulating capsule is to be reproduced, the chemical agent is taken out of the capsule as it is or in a gas containing water vapor and heated by heat obtained by solar light heat collection, the heat exchange of exhaust gas or the like to reproduce it.

Description

[Detailed description of the invention] (Industrial application field) This invention relates to a novel chemical heat storage capsule.

More specifically, the present invention uses heat generated by an exothermic reaction of a chemical heat storage material that undergoes a reversible reaction to heat a fluid, etc.
After the reaction, the chemical heat storage material is heated to store heat,
This invention relates to a new chemical heat storage capsule that can be used repeatedly.

(Prior Art) Various heat storage methods have been studied in the past. For example, there is a heat storage method that uses sensible heat using water as a heat storage medium to store solar thermal energy. However, heat stored in such an obvious manner does not have a relatively high energy density, so a large amount of heat storage medium is required.
The initial investment in a large-capacity container and a material with excellent heat insulation effect for the container is large, and a considerable amount of energy is released before use, so that good heat storage efficiency cannot necessarily be expected.

There is also a method of storing heat using latent heat, but in this case, the amount of heat stored is larger than that of explicit use, and the heat radiation temperature is constant at the melting point, but it is not suitable for Nagato's heat storage.

(Problems to be Solved by the Invention) Research is also being conducted to utilize chemical heat storage as a heat storage method that does not have the above drawbacks.

In this case, the amount of heat stored per volume is large and there is no need for heat retention, so long-term heat storage is possible.

Furthermore, a heat storage unit device has been proposed that uses the heat generated by the exothermic chemical reaction of a powder or solid heat storage material that undergoes a reversible reaction to perform dehydration through an endothermic chemical reaction (
JP-A-54-142401>. This method has the advantage that the heat storage material does not deteriorate due to repeated use and can be recycled. However, in the method of using fine powder heat storage material, which has been shown to be promising so far, if it is used repeatedly, the mesh material becomes clogged, probably because the mesh size is not appropriate, and the amount of filling is not appropriate. Due to the weight of the accumulated heat storage material, assimilation of the heat storage material itself progresses, resulting in a delay in the reaction rate.
In the end, it had the disadvantage that it could not be recycled and used repeatedly.

This invention was created in view of the above circumstances, and the fine chemical heat storage agent is not powdered and carried out together with gas, and the heat-resistant porous material is not clogged and the heat storage agent itself is not solidified. The object of the present invention is to provide a chemical heat storage capsule that can withstand repeated recycling and use.

(Means for Solving the Problems) The above object is achieved by a chemical heat storage capsule characterized in that the powder chemical heat storage material of the present invention is filled into a cylindrical body of a heat-resistant porous body.

The present invention also relates to a capsule characterized in that the heat-resistant porous body is made of porous ceramic or porous powder sintered body.

MOOH2OHM (OH)2 10 KCal (where M=Ca, )tg, Sr, BaQ=positive value (
(Exothermic)) Next, the chemical heat storage capsule of the present invention will be specifically explained using the drawings.

FIG. 1 is a partially cutaway perspective view of a chemical heat storage capsule 1 according to the present invention, in which a chemical heat storage material 2 is filled in a cylindrical body 3 made of a heat-resistant porous body. When exposed to a gas containing water vapor or a flow of water vapor, the chemical heat storage material in the capsule reacts with the water vapor.MO+H20';'! M (OH)
2 +QKcal), the fluid can be heated by its calorific value. Further, after the exothermic reaction is completed, it is possible to heat the chemical heat storage capsule by heating (M(OH)2→MO+H20) and store heat, and repeat these operations.

The chemical heat storage material 2 used in this invention has a reversible reaction [MO+
At least one substance selected from the group consisting of calcium oxide, calcium hydroxide, magnesium oxide, magnesium hydroxide, strontium oxide, strontium hydroxide, barium oxide, and barium hydroxide. It is of seeds. Further, it is also harmful if carbonate or the like is mixed in this chemical heat storage material in an amount of 0 to 10% by weight based on the chemical heat storage material. Further, the particle size of the chemical heat storage material 2 is 1 to 590 μm in the hydroxide state, more preferably 5 to 30 μm.
It is m.

The filling ratio of the chemical heat storage material 2 to the internal space of the cylindrical body is 60
~10% by volume, preferably ~40. ZO volume %.

If it is more than 60% by volume, the powder of the chemical heat storage material 2 will solidify after repeated use due to its own weight, and the heat generation and regeneration efficiency will be significantly lowered, and if it is less than 10% by volume, the desired effects such as heat generation cannot be obtained.

Further, the chemical heat storage material 2 is heated to store heat after the exothermic reaction is completed, and for example, in the case of calcium hydroxide, it is heat-treated at a temperature of 400 to 800°C, preferably 450 to 550°C, in order to reuse it. If heat treated at a temperature of 800°C or higher, chemical heat storage material 2 will not undergo a reversible reaction, and 4
Even when heat treated at a temperature of 00°C or lower, no reaction for heat storage occurs. 200-40 for magnesium hydroxide
Heat is stored at 0°C, 400-600°C for calcium hydroxide, 600-800°C for strontium hydroxide, and 800-1000°C for barium hydroxide.

The heat-resistant porous body used in this invention is an elongated cylindrical body that can be filled with the chemical heat storage material 2, and its cross-sectional shape in the direction perpendicular to the longitudinal direction is square or oval. , circular, triangular, etc.

In this case, the reaction rate can be adjusted by appropriately reducing the wall thickness of the tube or by decreasing the tube diameter. The wall thickness of the tube is 0.3
-3 mm, preferably 0.7-1.2 mm, the inner diameter of the tube is 2-50 mm, preferably 4-25 II1 m. In addition, the size of the pores is such that the filled chemical heat storage material 2 cannot be passed through the pores without clogging, and is preferably 1 to 10 μm, more preferably 3 to 10 μm.
It is m. The pore diameter here refers to the average pore diameter. The pores may communicate directly or intertwined within the porous body from the wall of the cylindrical body to the outer wall or vice versa. Moreover, the higher the porosity, the more desirable. Its porosity is usually 30-85%, preferably 40-85%.
It's %. When it is more than 85%, it is difficult to maintain the material strength, and when it is less than 30%, the reaction starts to slow down and is not practical.

In general, the material is SiC, carbon, alumina, activated alumina, glass, cordierite, mullite, lithium aluminum silicate, heat-resistant porous ceramic such as aluminum titanate, or Ni, Qu, △Ω, T.
At least one selected from the group consisting of heat-resistant porous powder sintered bodies such as i, Fe, Co, and alloys thereof is preferable.

In addition, since the heat-resistant porous body 3 is heated while being filled with the chemical heat storage material 2, it is made of a material that does not change in quality even at the processing temperature of the chemical heat storage material 2, and does not change in quality even after repeated treatments at the same temperature. Become. Note that heat-resistant porous ceramics have better pore homogeneity than heat-resistant porous powder sintered bodies, and are therefore more suitable for chemical heat storage encapsulation.

A chemical heat storage capsule consisting of such a chemical heat storage material 2 and a cylindrical body 3 made of a heat-resistant porous body is constructed by filling the chemical heat storage material 2 into a cylindrical body 3 made of a heat-resistant porous body, and then filling the chemical heat storage material 2 into a cylindrical body 3 made of a heat-resistant porous body A plug of a cylindrical body made of a heat-resistant porous body having a pore diameter of the same size or smaller as that of the cylindrical body 3 is used, and both ends are sealed using an inorganic binder such as clay, china clay, or ceramic cement. This operation may be performed by first forming a tube with one end sealed or a cylindrical body with only one end open, filling the inside with the chemical heat storage material 2, and then sealing the remaining end. In the chemical heat storage capsule thus obtained, the chemical heat storage material 2 does not come out of the cylindrical body, and there is no need to directly handle the powder thereafter, making the capsule easy to operate.

In order to insert this chemical heat storage capsule into a gas flow path containing water vapor and cause the chemical heat storage material to generate heat by reaction with the water vapor, the chemical heat storage material must be in the form of an MO-type oxide. It is. When M(OH)2-type hydroxide is heat-treated and subjected to an exothermic reaction immediately, it can be left as is, but when it is left for a long time and then used, or it must be stored in a state with a high amount of moisture or steam. If not, put dehumidified air, a reactive inert stable gas such as He, N2 or Ar gas into the capsule, or store it in a dehumidified state by covering it with water vapor impermeable plastic or plastic film. is preferred.

Furthermore, when heat is generated, it is usually at normal pressure, but by pressurizing it, higher temperature generation can be realized. Low-temperature regeneration treatment can also be realized by reducing the pressure.

(Function) When the chemical heat storage capsule 1 shown in FIG. 1 is put into a gas containing water vapor, the chemical heat storage material becomes MO+H20HM
) 2 + Reacts like QKCal and generates heat. This heat can be used to heat the fluid, heat the steam to higher temperatures, and operate turbines, engines, radiators, etc. In this case, the longitudinal direction of the chemical heat storage capsule is preferably perpendicular or approximately perpendicular to the flow of the fluid.

On the other hand, when regenerating chemical heat storage capsules,
It can be heated and regenerated as it is or by taking it out of a gas containing water vapor and using heat from solar heat collection, exhaust gas heat exchange, etc.

By repeating these operations, reuse becomes possible.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 A schematic diagram of an apparatus using the chemical heat storage capsule of the present invention is shown in FIG. A heat exchanger 4, a rotameter 5, and a reaction section 6 are set in a constant temperature bath 15 having a capacity of 1 m3. In the figure, 12 is a gas burner, 13 is a steam generator, 14 is a power source, 9 is a thermocouple, 10 is a heater, and 16 is a fan. The temperature inside the tank is maintained at a constant temperature of 120° C., and the superheated steam is passed through the copper pipe heat exchanger 4, and the steam that has been raised to the temperature inside the tank is introduced from the lower part of the reaction section.

Detailed views of the reaction section are shown in FIGS. 3(A) and 3(B).

FIG. 3 (A> is a schematic cross-sectional view of the reaction part in FIG. 2,
FIG. 3(B) is a perspective view of the main part of the reaction section in FIG. 2. In the figure, the heat-resistant porous pipe 3 is an alumina pipe with a diameter of 10 mmφ, a length of 5 Q mm, and a thickness of "+ mm" (pores of 3 to 4 μm).
m, porosity 42%) using a pipe with both ends closed,
Powdered calcium oxide CaO (quicklime > 0.6Q) was used as a chemical heat storage material. (Particle size is 0.59 mm as calcium oxide or approximately 10 μm as calcium hydroxide) Steam entering from the bottom flows into the porous pipe. reacts with CaO, causing a temperature rise.This temperature was measured with thermocouples 7 and 8, and the temperature rise ΔT was determined.

After flowing N2 into the reaction section to bring the sample to the set temperature, water vapor is introduced to start the reaction. In order to investigate the change in conversion rate over time, the reaction was allowed to take place for a certain period of time, then the steam was stopped and N2 was introduced to stop the reaction. After flowing N2 for several minutes, the sample was weighed and then placed in the electric furnace (approximately 700°C, 1
time) and Ca.

Weigh it after heating and decomposing it.

The CaO mass is 0.69, and the water vapor flow is 2°0~
The relationship between the conversion ratio (m1 is the mass after reaction, ~2 is the mass after heating) and time was determined and is shown in FIG.

Matc water vapor flow lm = 6.2 cl/min, CaO
The relationship between conversion rate and time was determined for quality ff1o, 6c+ and 0.3C7 and is shown in FIG.

Furthermore, test results and actual measurements (city = 5.2 g/min.

m=0.6g) is shown in FIG.

From the above results, the conversion rate depends on the water vapor storage temperature, and furthermore, the conversion rate is approximately 5℃ over time per chemical heat storage material capsule.
A temperature rise of (m-5°2o/min, m=
0.6g>.

(A: porous tube heat transfer area, h: heat transfer coefficient, To: outlet steam temperature, T: inlet steam temperature, C: Trial example 2 0.105 to 0.250 mm calcium oxide (0.5
Using each alumina porous body with pores of 1,2.3 to 4 μm, the influence of the pores of the porous body was investigated using the same method as in Example 1, and the results are shown in Figure 7. .

As can be seen from the figure, the time θ at which ΔT reaches its maximum, that is, θAyuX, is almost constant, and within this range, the influence of the pores of the porous body was not seen much.

Example 3 The chemical heat storage material capsule (calcium oxide 0.60) used in Example 1 was taken out from the reactor after the reaction was completed, heated and regenerated at 600'C x 0° for 2 hours, and then carried out again. Same method as Example 1 (output = 6.20/
min, m=o, 6q), a temperature increase of about 5°C was obtained for each chemical heat storage capsule.

After the above heating regeneration treatment 10 times, when carried out in the same manner as in Example 1, the temperature was approximately 5°C per chemical heat storage capsule.
A temperature increase of .

Comparative Example Calcium oxide used in this invention (0.105-0.
250 mm, 0.6 g> was wrapped in a heat-resistant glass mesh cloth with a pore diameter of 20 μm and reacted in the same manner as in the apparatus of Example 1. In both cases, the exothermic reaction occurred. , could not be used for playback.

These embodiments are merely for understanding the invention, and various modifications may be made thereto without departing from the spirit and scope of the invention.

(Effects of the Invention) As described above, this invention is a chemical heat storage capsule in which a powdered chemical heat storage material is filled into a cylindrical body made of a heat-resistant porous material. Since the pores of the porous body are set to be relatively smaller than the particle size when the powder is pulverized by reaction, the porous body is not transported out of the porous body together with the gas. It can be recycled and used repeatedly without clogging and because of the appropriate amount of powder, it does not solidify. Furthermore, the generated heat can be used to further heat the steam to a higher temperature and further operate turbines, engines, radiators, etc. In addition, it is possible to regenerate heat storage using waste heat, heat collected by solar collectors, heat from electric furnaces, high frequency heating (microwave oven), and infrared heat lamps as regenerative heat sources for chemical heat storage material capsules. .

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of a chemical heat storage capsule showing an embodiment of the present invention, FIG. 2 is a schematic diagram of an apparatus showing an embodiment of the chemical heat storage capsule (A> is a schematic sectional view of the reaction section in FIG. 2, FIG. 3(B) is a perspective view of the main part of the reaction section in FIG. 2, and FIGS. 4 and 5 are reaction times in an embodiment of the chemical heat storage capsule of the present invention. FIG. 6 is a diagram showing the relationship between the reaction time and temperature difference (ΔT) in an embodiment of the chemical heat storage capsule of the present invention, and FIG. 7 is a diagram showing the relationship between the chemical heat storage capsule of the present invention and the rate of change. It is a diagram showing the relationship between the pore diameter of the porous body and the time until the maximum temperature is reached (θmax) in one embodiment of the capsule. 1... Chemical heat storage capsule, 2... Chemical heat storage material, 3
...A cylindrical body of a heat-resistant porous body, 4...A heat exchanger,
5... rotor router, 6... reaction section, 7.
8, 9...Thermocouple (thermometer), 10... Heater,
11...Fan, 12...Gas burner, 13...Steam generator, 14...Power supply,
15... Constant temperature chamber, 16... Fan,
17...Silicone rubber. Patent applicant: Mitsui Grinding Wheel Co., Ltd. (and 1 other person) Engraving of the drawing (no changes to the content) Drawing 1 Drawing 2 @ Drawing 3 (A)
(8＠Figure 4, Figure 5, Figure 11 M (?fi Time Yudai 6)
Figure @ 7 Figure Wandering υ! :P] Procedure Neichi Masai H (Method) 1. Indication of the case 1985 Special Mu' [Application No. 57,669 2. Name of the invention Chemical thermal storage capsule 4. Agent

Claims (3)

[Claims] (1) A chemical heat storage capsule characterized by filling a cylindrical body of a heat-resistant porous body with a powder chemical heat storage material. (2) The capsule according to claim 1, wherein the heat-resistant porous body is made of porous ceramic or porous powder sintered body. (3) The capsule according to claim 1 or 2, wherein the powder chemical heat storage material is at least one material that performs the following reaction. MO+H_2O■M(OH)_2+QKcal (where M=Ca, Mg, Sr, Ba, Q=positive value (heat generation)
)