JPS61285284A - Chemical heat accumulation and apparatus therefor - Google Patents

Abstract

PURPOSE:To enable the accumulation of heat in high efficiency at a low cost, by generating NH3 gas in a high-temperature reactor filled with a specific powdery ammine complex, absorbing the gas in a low-temperature reactor, absorbing the generated NH3 gas in the complex in the high-temperature reactor and recovering the heat of reaction. CONSTITUTION:A high-temperature reactor 1 filled with powdery nickel chloride ammine complex 9 is heated to 100-200 deg.C with a heat-exchanger 5 for heating, and the generated ammonia gas is introduced into a low-temperature reactor 2 containing liquid ammonium nitrate ammine complex 15 in sealed state and is absorbed in the complex. The low-temperature reactor 2 is heated to normal temperature (0-30 deg.C) to release ammonia gas from the ammonium nitrate ammine complex 15 and the generated ammonia gas is introduced into the high-temperature reactor 1 and absorbed in the nickel chloride ammine complex 9. The generated reaction heat is recovered with the heat-exchanger 6 for recovery to effect the chemical heat-accumulation.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a chemical heat storage method and its device, and more specifically, it is applicable to late-night electricity, factory waste heat, power plant waste heat, garbage incinerator waste heat, etc. This method utilizes an inexpensive heat source, stores the heat in a heat storage device, radiates the heat when necessary, and recovers it for use in steam production, hot water production, space heating, etc.

[Conventional technology]

In recent years, interest in energy issues has increased, and various methods for effectively utilizing energy have been invented, among which heat storage technology is attracting attention.

This heat storage method includes sensible heat storage, latent heat storage, and chemical heat storage. The chemical heat storage method, which uses chemical reactions, can be said to be a promising method because it has a high heat storage density and long-term heat storage is possible if the reactants are separated.

Various chemical heat storage systems have been studied and proposed. That is, if a high-temperature gas phase reaction of 1000° C. or higher is used, there is a dissociation reaction of CaC01, Mg5O, and HBr, or a catalyst is required for the forward and reverse reactions. 500
Ca (OH)1, NH,, NH4H3O3, SO3
There is a methane reformation reaction, but Ca(OH),
With the exception of the dehydration reaction, all reactions require catalysts, and their application as chemical heat pipes in nuclear power generation and other applications is being considered.

Examples of reactions that utilize relatively high temperatures of 200 to 500°C include the water absorption reaction of sulfuric acid and the H2 addition reaction of Mg (OHh benzene-cyclohexane).
Reactions that can use affordable waste heat below 0℃ include hydrogen storage alloys, silica gel and zeolite adsorption reactions, nickel chloride ammonium salt reactions, calcium chloride water and methanol adsorption reactions, NaI ammonia absorption reactions,
Typical reactions include the dehydration reaction of borax and the dehydration reaction of hydrated sodium sulfide. Other chemical heat storage reactions include:
Examples include photochemical reaction heat storage using norbornagene, etc.

[The problem that the invention attempts to solve]

When putting chemical heat storage (chemical reaction heat storage) into practical use, reaction examples are naturally constrained by the temperature of the heat source such as exhaust heat and the usable temperature range. It is necessary to select a reaction from the viewpoints of ease of separation, transportation, and storage of gases and liquids as media, safety as a reaction and drug, and low drug cost.

Therefore, as a chemical reaction heat storage method that keeps the heat source temperature at 200° C. or lower with a low level of waste heat in mind, there is a reaction between metal chlorides and ammonia. Chemical reaction heat storage consists of a reaction on the high temperature side and a reaction on the low temperature side, and nickel chloride hexaammonium salt (Nf
CLm·6NHs) is said to be a desirable material from the viewpoint of heat storage density (reaction heat amount/weight or volume). On the other hand, calcium chloride/tetraammonium salt (
Possibly CaCA2/4NHs). Each of the above reactions is shown in the following formulas (1) and (2).

N'xCLz・6NHz (solid): N1Ct snow・2NHs
(solid) +4NH, (gas) (1) CaCAz @ 4NH3 (solid) + 48Hs (gas); CaC22.8NH3 (solid) (2) Compare the rightward reaction rates of reaction equations (1) and (2) in the heat storage process It may be a bit vague, but the reaction equation (1) for the heat dissipation process, (
It is desired that the leftward reaction speed of 2) is relatively fast. However, the leftward reaction of Reaction Formula (2) has the disadvantage that it is very slow at room temperature of 0 to 30°C and is therefore impractical.

Moreover, it is also possible to use an ammonia liquefaction/vaporization reaction instead of the reaction of the above reaction formula (2).

Although the vaporization reaction of ammonia can be carried out extremely quickly under reduced pressure, it has the disadvantage that the power of a compressor is required during liquefaction. However, although the ammonia vaporization reaction is effective in large plants that require pressurization of about 8 degrees at room temperature (20° C.), a low-temperature ammonia storage method that requires as little power as possible is desired.

As a low-temperature ammonia storage method, there is a method of absorbing and storing ammonia in liquid ammonium. This is an advantage of the liquefaction method, in that it has a fast ammonia release rate and does not require external mechanical energy when liquefying ammonia gas. There is sodium NaI. Sodium iodide (NaI) has a relatively wide liquid phase region, making it a preferable substance, but it has the disadvantage that it is not desirable because a solid phase may precipitate at temperatures below 25°C and anthonia pressures below 3 atmospheres.

The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a chemical heat storage method and an apparatus thereof that can quickly advance the reaction on the low temperature side in the heat dissipation process and recover heat in a short time. It is something.

[Means for solving problems]

The first means for achieving the above object corresponds to the embodiment.
This will be explained using FIGS.

In the chemical heat storage method of the first invention, a high-temperature reactor filled with a powdered nickel chloride/ammine complex is heated to 100 to 200°C, and the generated ammonia gas is transferred to a low-temperature reactor filled with a liquid ammonium nitrate/ammine complex. Ammonia gas is generated from the ammonium nitrate/ammine complex by heating the low temperature reactor at room temperature of 0 to 30C, and the generated ammonia gas is guided to the high temperature reactor and absorbed by the nickel chloride/ammine complex. It consists of a heat dissipation process in which the reaction heat is recovered.

The second chemical heat storage device includes a heat exchanger (5
), (6) A high temperature reactor (1) filled with powdered nickel chloride ammine complex (9) is immersed in a heat transfer cylinder (4) equipped with・
A gas control valve (3) is provided in the gas pipe (12) connecting the low temperature reactor (2) filled with the ammine complex (15), and the upper space (18) and the lower part of the low temperature reactor (2) are connected to each other. A diffuser pipe (13) is provided to connect the upper space (18) and the diffuser pipe (
13) and a gas circulation pipe (16) equipped with a blower (14).
).

[Effect]

FIG. 1 shows a chemical heat storage cycle using a combination of nickel ammonium chloride and ammonium nitrate. The reaction formulas are summarized as the following formulas (1) and (3).

High temperature side reaction NiC4・6NH3 (solid) 2NI C4・
2NHs (solid) + 4NHs (gas) (1) Low temperature side reaction NH,NO3・nNH3 (liquid) + mNH3 (gas):
NH4NO3-(n+m)NH3 (liquid) (3) Ammonium nitrate/ammine complex can form a liquid ammonia compound even at room temperature and low pressure, so it can be used for low-temperature side reactions, and nickel chloride ammonium salt (nickel chloride ammonium salt) can be used for high-temperature side reactions.
A chemical heat storage cycle can be formed by combining the two using nickel chloride/ammine complex).

The action of the chemical heat storage cycle will be explained with reference to FIG. In the heat storage process, nickel chloride hexaammonium salt is thermally decomposed by receiving heat a of 150 to 200 degrees Celsius such as exhaust heat, and the generated ammonia gas is absorbed and stored in liquefied ammonium nitrate.In the heat release process, Ammonia gas is generated from the liquefied ammonium nitrate/ammine complex in response to low-level heat such as outside temperature, and the ammonia gas moves due to the pressure difference and chemically reacts with nickel chloride/diammonium salt, releasing reaction heat. In addition, in the heat storage process, the reaction on the high temperature side is 59.
It absorbs 4 moles of heat and dissociates ammonia, and the low-temperature side reaction absorbs it and releases 1 mole of 6.2 Kd of heat, and in the heat dissipation process, heat is transferred in and out in the opposite manner. Therefore, the amount of heat stored in the heat storage process is △H=59.1+4
(-6,2) = 1 mole per 34°3. Reaction formula (
The number of moles (m) of ammonia absorbed in 3) is
If the pressure is constant, the lower the temperature, and if the temperature is constant, the higher the pressure, the greater the value of m. The equilibrium composition at 0°C and 1 atm is the following reaction formula (4), where n = 0.9 mol, m = 1.75 mol, (n+m)-2.65 mol, and at 0° and 4 atm, (n+m ) zo, 9 moles.

NH4No, 0.9NHs (liquid) + 1.75NH
s (GaX)-”NH4NOx ・2.65NHs
Solution C) (4) Therefore, to absorb 4 moles of ammonia gas generated in reaction formula (1), 2.3 moles of NH4No
,is necessary.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3.

Reference numeral 4 denotes a heat medium tank that is completely covered with a heat insulating material 7 and into which a heat medium 8 is injected almost completely. A reactor 1 is provided. 10 is a fin for promoting heating of the nickel chloride ammonia salt 9 in the high temperature reactor 1;
11 is nickel chloride ammonia salt 9 in the high temperature reactor 1
It is a thin mesh tube that cuts the powder and collects only the gas of the liquid salt 9. 5 is a heating heat exchanger that heats the heat medium 8 using waste heat or a cheap heat source, and 6 is a recovery heat exchanger that recovers heat from the heat medium 8 for use. 2 has a certain amount of liquid ammonium nitrate/ammine complex 15 sealed inside, and an upper space 18 and an aeration pipe 13 below. 8 and a diffuser pipe 13 are connected through a gas circulation pipe 16 equipped with a blower 14.

12 is a gas pipe that connects the high temperature reactor 1 and the low temperature reactor 2 and has a control valve 3 in the middle.

Note that the heat medium 8 is made as small as possible to improve thermal response and to allow the tank volume to be designed to be small. Further, the material of the heating medium 8 is determined by the chemical reaction employed, but in this case, there is a possibility of heating up to 200° C. during the heat storage process, so it is necessary to select a heating medium with excellent heat resistance.

In FIG. 2, waste heat or a cheaply available heat source is used to heat a heat medium 8 through a heating heat exchanger, and as a result, a high temperature reactor 1 is heated.
The nickel chloride ammonia salt 9 inside is heated and ammonia gas is generated. The generated ammonia gas is collected from the mesh pipe 11 that cuts the powder of the liquid salt 9, and is transported from the high temperature reactor 1 to the low temperature reactor 2 by the ammonia pressure difference generated through the gas pipe 12. The ammonia gas is then sent to the upper space 18 of the low-temperature reactor 2, and is sucked from the gas circulation pipe 16 by the blower 14, and the low-temperature reaction t
Air is diffused into the liquid of the ammonia nitrate/ammine complex 15 through the air diffuser pipe 13 provided at the bottom of the i2. In this process, gaseous ammonia is converted into ammonia nitrate/ammine complex 15
is absorbed to form ammonides.

In addition, since the thermal conductivity of the powdered nickel chloride ammonium salt 9 is low, there is a concern that the ammonia elimination reaction will not be completed within a predetermined time if only the fins 10 are provided in the container of the high temperature reactor 1. . Therefore, the speed of the rightward reaction in reaction formula (1) is relatively slow and takes time compared to the leftward reaction.

For example, when nickel chloride hexaammonium salt is heated at 200° C., the deammonification rate is 8096 over about 8 hours, depending on the equipment conditions such as heat transfer fins. This problem can be solved by using a rotary high temperature reactor shown in FIG. 3 to accelerate the reaction. That is, the high-temperature reactor 1 shown in FIG. 3 is installed horizontally in a heat medium 8 and is gently rotated in a heat medium tank 4 by a motor and a speed reducer 19 via a rotating shaft 20, thereby removing the powder inside. The nickel chloride ammine complex is mixed and uniformly contacts the fin 10 and the container wall,
The ammonia elimination reaction is accelerated.

Figure 4 1cNi Ct, -6NHs system NH4NO
The chemical heat storage operating line of the s system is shown below. For example, 16
When heating nickel chloride hexaammonium salt at 0 to 170°C, the ammonia pressure equilibrates at 1 v-. At that pressure, the temperature of the ammonium nitrate/ammine complex is 20 to 30°C, at which absorption and removal of ammonia are in equilibrium.

Therefore, if the liquid temperature of the ammonia nitrate/ammine complex is low, ammonia absorption will proceed and the equilibrium ammonia pressure will decrease, which is favorable for the reaction. Therefore, it is preferable to provide a heat exchanger 17 capable of cooling or heating the gas circulation pipe 16 as shown in FIG.

During the heat storage process, as the high temperature reactor 1 is heated, the rightward reaction in reaction formula (1) progresses and the ammonia pressure also decreases, so the heat storage reaction stops when it reaches equilibrium with the ammonia pressure in the low temperature reactor 2. However, in order to proceed with the rightward reaction as much as possible, it is necessary to keep the temperature of the low-temperature reactor 2 low.

When the heating of the heat storage reaction is completed and the temperature of the high-temperature heat transfer medium 4 decreases, ammonia flows back from the low-temperature reactor 2 to the high-temperature reactor 1. The control valve 3 provided at 12 must be controlled.

In the heat dissipation process, the control valve 3 is opened and the low temperature reactor 2
When heated to an appropriate temperature, ammonia gas is generated and transferred to the high temperature reactor 1, and the nickel chloride ammonia salt reacts with ammonia and generates heat. Recovering this heat completes the chemical heat storage cycle.

Although ammonium nitrate/ammine complex was used as the liquid ammonium compound in the above examples, it is not limited to the above examples (for example, ammonium chloride (NH4C1), ammonium bromide, (NH4SCN), lithium nitrate (LiN
Os) etc. may also be used. Among them, NH4Br, N
An imaginal line of liquid ammonia of H4Ct is shown in FIG. At normal pressure of ammonia pressure I Wd, the range of normal temperature is 0 to
At 30℃, NH4Ct, NH4Br, NH4NO3
is a good candidate liquid ammonide because it can be manipulated.

〔effect〕

According to the present invention, in the heat dissipation process, the deammonification reaction from the low-temperature reactor proceeds in approximately 1 hour at 0°C, so the conventional deammonification reaction of CaCLz・f3 NH3 is carried out at 0°C.
It takes approximately 5 hours to recover the heat in a shorter time compared to the 6096 reaction rate. Further, according to the present invention, anthonia nitrate
Since the circulating aeration method is adopted for the ammonia absorption reaction of the ammine complex liquid, the ammonia absorption rate can be reduced to 1 within about 5 hours.
0096, which falls within the time required to complete the deammonization reaction of the nickel chloride hexaammonium salt, so this reaction is not rate-limiting.

[Brief explanation of drawings]

FIG. 1 is a block diagram explaining the chemical heat storage method of the present invention, FIG. 2 is a schematic sectional view showing the chemical heat storage device of the present invention, and FIG. 3 is a schematic sectional view showing another embodiment of the high temperature reactor. FIG. 4 is an explanatory diagram showing the chemical heat storage operating line. Explanation of symbols 1...High temperature reactor 2...Low temperature reactor 3...
・Control valve 4...Heat medium tank 5...Heating heat exchanger 6...Recovery heat exchanger 7...Insulating material
8... Heating medium 9... Nickel chloride ammine complex powder 10... Fin 11... Mesh tube 12... Gas pipe 13... Diffusion pipe 14...
・Prower 15...ammonia nitrate/ammine complex 16...gas circulation pipe 17...-heat exchanger 18--upper space 19...motor and speed reducer 3 < 1 ・Kiichi 4 Shin 1 ・Base heat stage (high 5 side) (temperature side) Fig. 1 Fig. 2 Fig. 3 Fig. 3 Jl Jl ('C) 2.0 25 3.0 35
4.0103/T (K”') Fig. 4

Claims (1)

[Claims] 1. A high-temperature reactor filled with a powdered nickel chloride/ammine complex is heated to 100 to 200°C, and the generated ammonia gas is introduced into a low-temperature reactor filled with a liquid ammonium nitrate/ammine complex. The absorption process and the heating of a low temperature reactor at room temperature of 0 to 30°C to generate ammonia gas from the ammonium nitrate/ammine complex, the generated ammonia gas is led to the high temperature reactor, where it is absorbed by the nickel chloride/ammine complex and generated. A chemical heat storage method that consists of a heat dissipation process that recovers the heat of reaction. 2. The liquid ammine complex sealed in the low temperature reactor (2) is an ammine complex of ammonium chloride, ammonium thiocyanate, ammonium bromide, or lithium nitrate containing ammonium nitrate, or any mixture thereof. A chemical heat storage method according to claim 1. 3. Powdered nickel chloride/ammine complex (
9) is immersed in the high temperature reactor (1) and the liquid ammonium nitrate/ammine complex (15
) A gas pipe (12) connecting the low temperature reactor (2) filled with
is equipped with a gas control valve (3) and a low temperature reactor (2).
Upper space (18) above and air diffuser pipe (13) below
A chemical heat storage device characterized in that an upper space (18) and a diffuser pipe (13) are connected by a gas circulation pipe (16) provided with a blower (14).