JPS5925159B2 - Heat release and storage method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a chemical heat release/storage method.

The need for heat storage is being avoided from the standpoint of effective energy use.

Heat dissipation and storage methods that utilize chemical reactions have many advantages, such as their high energy density and the ability to store heat for long periods of time because they do not necessarily require heat retention.

However, this method requires a heat exchange reactor that allows complete separation of chemical species and takes heat transfer into account so that heat can be easily released and stored.

Among chemical heat storage bodies, heat storage bodies that utilize the reaction between halides and NH3 gas can easily liquefy NH3 gas, so the NH3 storage container can be made smaller, and the heat dissipation and storage reaction is carried out with NH3 gas. It is attracting attention because it is easy to separate reactive species.

However, many complexes of halides and NH3 are considered to be operable at NH3 gas pressures of 0 to 5 kg/crA.
Under certain temperature conditions, many substances are in a solid state, and in order to utilize the heat of reaction between a solid and a gas, it is necessary to develop a reactor that takes heat conduction into consideration.

Therefore, if a liquid material is selected under these conditions, the reaction heat of the gas-liquid reaction will be utilized, and the heat transfer properties of the heat exchange reactor will be significantly improved.

ZnCl2 is 31 compared to CaCl2 ・MgCl2
Although it melts at a low temperature of about 8°C, its vapor pressure increases rapidly when the melting point is exceeded.

Therefore, if ZnCl2 is reacted alone and in a molten state with NH3 to release and store heat, ZnCl2 vapor will be mixed into the NH3 gas, making it difficult to separate it.

The present invention proposes a method of controlling the vapor pressure of ZnCl2 and carrying out the heat dissipation and storage reaction in a liquid and gas state with good heat transfer.

That is, a mixture of 0.1 mol - 0.8 mol of N a C1 or KCI per 21 mol of ZnCl and NH3
This heat release/storage method is characterized by reacting with a gas to form a complex and releasing heat, and thermally decomposing the complex and storing heat.

When NaCl or KCI is mixed with ZnCl2, ZnCl2 becomes NaCl or KCI and Na2ZnC in the molten state.
1”t Forms complex ions such as K2ZnC12+ and Z
The activity of nC1□ is decreased.

Therefore, by adding N a C1 or KCI, Z'
As the vapor pressure of nCl2 decreases drastically, ZnCl2
The melting temperature is also lower than when it is used alone.

The mixing amount of NaCl or KCl is 0.1 mol to 0.8
The reason why it is limited to the molar range is that below 0.1 mol, the effect of lowering the melting point and the vapor pressure of ZnCl2 is small, and when it exceeds 0.8 mol, the melting point gradually decreases with the amount added. This is because as the ZnCl2 content increases, the ZnCl2 content decreases and the energy density as a heat storage body decreases.

A particularly preferable addition amount is NaC per 21 mol of ZnCl.
1 or KCI 0.5 to 0.7 mol.

The heat radiation and storage power method of the present invention will be explained with reference to the drawings.

In Figure 1, ZnCl2 and NaCl or KCI
A mixture of NH3 complexes (hereinafter referred to as mixture) is placed in the heat exchange reactor 1.

This heat exchange reactor 1 is connected to an NH3 holder 2 through a connecting pipe 3.

4 is an on-off valve installed in the connecting pipe 3. When a heat medium such as exhaust gas is supplied to the heat transfer tube 5 attached to the heat exchange reactor 1, the NH3 complex in the mixture in the reactor 1 formed when the on-off valve 4 is opened is thermally decomposed, and NH3 is transferred to the connecting tube 3. Pass through and enter NH3 holder 2.

When the thermal decomposition reaction is completed, the on-off valve 4 of the connecting pipe 3 is closed as shown in FIG.

When using the stored thermal energy, as shown in Fig. 3, the NH3 holder 2ONH3 gas is introduced into the heat exchange reactor 1 through the connecting pipe 3 by opening the on-off valve 4, and the mixture reacts with the NH3 gas to form a complex. and releases the heat of reaction.

The heat is recovered and utilized by an appropriate heat medium supplied to the heat transfer tubes 5.

It is also possible to dissipate and store heat while controlling the pressure of the heat exchange reactor 1 and the NH3 holder 2ONH3 gas by installing a vacuum pump or a compressor in the middle of the connecting pipe 3.

Further, the heat exchanger tubes 5 of the heat exchange reactor 1 may be the same for heat release and storage as shown in FIG. 1, or heat exchanger tubes may be provided depending on each case.

Although it is desirable to keep the heat exchange reactor 1 warm, it does not necessarily need to be kept warm.

When using the stored thermal energy, if the mixture in the heat exchange reactor 1 is solidified, NH3 may be supplied after the mixture is heated by the heat exchanger tube 5 and melted, or the mixture may be solidified. Even if NH3 is supplied as it is, the mixture will be melted by the heat of reaction, so the heat medium can also be passed through the melting diameter heat transfer tube 5.

In the NH3 holder 2, it is preferable to store NH3 in liquid form in order to reduce the volume of this holder.

In that case, the liquefaction device using a compressor etc. is connected to the connecting pipe 3.
will be installed in the middle of.

Further, it is also possible to store NH3 as a complex by placing halides that form a complex with NH3 gas different from the mixture in the holder 2.

The effects of the present invention will be explained using experimental results.

Experimental example 1 An experimental apparatus as shown in Figure 1 was made, and ZnC was placed in the heat exchange reactor.
12 was filled, heated to 320° C., and then NH3 gas was bubbled gradually.

At the same time as the NH3 gas was supplied, heat medium oil at 320° C. was poured into the heat transfer tube, and the amount of heat released was determined from the difference between the inlet temperature and the outlet temperature of the heat medium oil, and the amount of heat released was approximately 13 kcal per mole of supplied NH3.

When 2 mol of NH3 was supplied per 1 mol of ZnCl2, the pressure of NH3 in the pyrolysis reactor reached about 1000 TMLHg.

Next, NH3 was separated from the complex by reducing the pressure in the thermal decomposition reactor while flowing heat medium oil at 320°C.

When the pressure reached 50 mmHg, the complex solidified, and even if the pressure was further reduced, it was difficult to decompose the complex.

When the solidified material was analyzed after cooling, it was found that ZnCl2
0.4 mol of NH3 remained in 1 mol.

After repeating this experiment three times, Z was found at the NH3 gas outlet.
The fourth repetition was difficult because the nCl2 solidified.

This is considered to be because ZnCl2 vapor was condensed and solidified at the low temperature NH3 gas outlet when the pressure was reduced.

Experimental Example 2 (Example) As in Experimental Example 1, a heat exchange reactor was filled with a mixture of 21 mol of ZnCl and 10.6 mol of NaC.

Since it melted when heated to 270°C, NH3 gas was supplied without flowing the 270°C heat transfer oil.

The amount of heat released was calculated from the difference between the inlet temperature and the outlet temperature of the heat transfer oil, and the amount of heat released was approximately 13 kcal per mole of NH3 supplied.

When 2 moles of NH3 were supplied per mole of ZnCl2, the pressure of NH3 in the pyrolysis reactor was 500 mmHg.

When NH3 was supplied until the pressure of NH3 reached 1000 mmHg, 45 moles of NH3 reacted with 21 moles of ZnCl.

Next, while the heat transfer oil at 270°C is flowing, reduce the pressure and NH3
The complex was decomposed.

Solidification did not occur even when the reactor pressure reached 20 rran.

When this material was cooled and solidified and analyzed, ZnCl21
0.1 mole of NH3 remained.

This experiment was repeated 12 times, but no problems occurred with the experimental equipment.

Experimental Example 3 As in Experimental Examples 1 and 2, a mixture of 21 mol of ZnCl and 0.7 mol of KCl was charged into a heat exchange reactor, and the mixture melted at 260°C.

Experimental examples 1 and 2 while flowing heat transfer oil heated to 270°C
When similar experiments were carried out, almost the same results as in Experimental Example 2 were obtained, and no problems occurred with the experimental equipment even after seven repeated experiments.

As can be clearly seen from the above experimental examples, according to the present invention, Z
Since NaCl or KCl is mixed with nCl2, Zn
Z at various times to change the complex formation ability of Cl2 and NH3
It has the effect of suppressing the vapor pressure of nCl2 and widening the range of liquids that can easily exchange heat.

[Brief explanation of drawings]

FIGS. 1 to 3 are conceptual diagrams of the heat dissipation and storage system. 1... Heat exchange reactor, 2... NH3 holder, 3...
... Connecting pipe, 5... Heat transfer tube.

Claims (1)

[Claims] I NaCl or KCl for 1 mole of ZnCl
A heat release/storage method characterized by reacting a mixture of 0.1 mol to 0.8 mol of NH3 gas with NH3 gas to form a complex and releasing heat, and thermally decomposing the complex and storing heat. Method.