JP2556223B2 - Method and apparatus for generating chemical cold heat - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical cold heat generating method and an apparatus therefor utilizing an endothermic action associated with a chemical reaction.

[0002]

2. Description of the Related Art In recent years, particularly in summer, people's demands for cooling have been increasing year by year, and as a result, the amount of power consumption has become unable to keep up with the demand.

Therefore, recently, as a refrigeration / cooling system for coping with such a situation, a chemical refrigeration system utilizing the endothermic / exothermic action associated with the chemical change of a substance.
Research on (so-called chemical heat pump systems) is becoming popular.

In the broad sense, the chemical refrigeration system includes an absorption refrigeration system and a hydrogen storage refrigeration system which have already been put to practical use, but in a narrow sense, it mainly uses a heat pump principle by a general chemical reaction. Become. And most of the chemical refrigeration systems mainly for such general chemical reactions are still in the research stage. For example, the candidate substances which have been studied up to now and their reaction examples are listed below. Table 1 is known.

(Table 1: Candidate substances and reaction examples)

[0006]

[Table 1]

FIG. 4 shows the structure of a chemical absorption / exothermic reaction system currently used, taking the case of the inorganic substance "slaked lime Ca (OH ₂ )" in the above table as an example. . In the figure, reference numeral 11 is a first reaction vessel, 12 is a second reaction vessel, and these first and second reaction vessels 11 and 12 are connected to each other via a valve 13.

[0008] Then, quick lime C is contained in the first reaction vessel 11.
aO is charged, and water H ₂ O is charged in the second reaction vessel 12.

Here, the reaction of slaked lime Ca (OH ₂ ) is

[0010]

[Equation 1]

The reaction proceeds in one direction under both temperature and pressure conditions. That is, the respective reactions proceed at different pressures under isothermal conditions and at different temperatures under isobaric conditions. Therefore, when quicklime CaO is put in the first reaction vessel 11 and water H ₂ O is put in the second reaction vessel 12 as shown in the figure, the equilibrium state between the pressure P and the temperature T of the substance in each vessel is schematically shown. As shown in FIG. 5, assuming that this system has the same temperature To, a pressure difference of ΔP occurs between the two containers 11 and 12. Therefore, when the valve 13 is opened in this state, the pressure of the second reaction container 12 having a high pressure is lowered, so that the water is boiled and the generated water vapor passes through the tube to the first position.
It moves to the reaction container 11 of and reacts with quicklime CaO. As a result, the reaction heat is released in the first reaction vessel 11,
The temperature of the reaction container 12 decreases due to the evaporation of water. Based on this basic principle, the reaction conditions can be arbitrarily controlled to utilize heat absorption or heat generation, or by using the product as a heat storage material, an air conditioning system is constructed (for example, published by Nikkan Kogyo Shimbun Co., Ltd. Heat pump "P52-P53).

[0012]

[Problems to be Solved by the Invention]
According to the (H) ₂ / H ₂ O / CaO reaction system, for example, a high temperature exhaust heat of about 673 K and a cold heat source of normal temperature water produce 800
It has also been reported that heat having a temperature of K or higher can be generated, and research into practical application as a heating system has been made.

However, when the reaction system of any of the above-mentioned various candidate substances including the system is examined as a cold heat generation system for cooling, the equilibrium temperature is higher than room temperature, and side reactions occur. However, there are problems in that it is easy to occur and efficiency is low, and the device is complicated, and there is no effective report as a cooling heat generation system for cooling at present.

[0014]

Claims 1 and 2 of the present application
The chemical cold heat generating method and the apparatus thereof according to the invention described above are provided for the purpose of solving the above-mentioned conventional problems, and are configured as follows.

(1) Method for generating chemical cold heat of the invention according to claim 1 In the method for chemical cold heat generation of the present invention, cold heat is obtained by evaporating liquefied isobutylene and then absorbing it in an aqueous tertiary butyl alcohol solution. It is characterized by having done.

(2) The invention according to claim 2 The chemical cold heat generating device of the present invention comprises, for example, as shown in FIG. 1, a storage means 5 for storing liquefied isobutylene supplied from a predetermined supply means, and the storage means 5. An isobutylene stored in the storage means 5 by including a reaction container 6 which is communicated through an open / close valve 2 and stores therein a predetermined amount of a tertiary butyl alcohol aqueous solution. Is evaporated and the third container in the reaction vessel 6 is
It is characterized in that cold heat is obtained by absorbing it in an aqueous butyl alcohol solution.

[0017]

The chemical cold heat generating method and the apparatus thereof according to the present invention are configured as described above, and as a result, the following action is achieved corresponding to each configuration.

That is, first, in the chemical cold heat generating method of the present invention, as is clear from the above description, first, a new reaction system of isobutylene / water / tertiary butyl alcohol is newly found and used.

In the chemical cold heat generating method such as the method of the present invention, it is essentially required that the above-mentioned equilibrium temperature is close to room temperature and that a side reaction hardly occurs and a reversible reaction is possible.

[0020]

[Equation 2]

The reaction system according to the method of the present invention represented by the above formula (2), for example, has an equilibrium temperature of about 56.0 ° C. and reacts reversibly in the presence of a catalyst without side reactions. In addition, from the results that have already been studied for the high temperature part, the isobutylene has a saturated vapor pressure of 2.6 atm at 20 ° C., which is considerably higher than the other two components, so separation is easy, so a refrigeration system is assumed. It is suitable for use as a refrigerant for generating cold heat.

Therefore, in the chemical cold heat generating method of the present invention, the reaction system is employed so that the liquefied isobutylene is first evaporated and then absorbed in the tertiary butyl alcohol aqueous solution, and the effective absorption of isobutylene by the absorption is performed. Sufficient cold heat is obtained by utilizing the latent heat of vaporization due to the evaporation action of.

In the chemical cold heat generator of the present invention,
Adopting the above-mentioned configuration on the premise of the above method, first, liquefied isobutylene is collected from the predetermined liquefied isobutylene supply means in the storage container 5, while the reaction container 6 is further provided.
Is charged with a tertiary butyl alcohol aqueous solution. Here, when the on-off valve 2 between them is opened, the storage means 5
Liquefied isobutylene inside is evaporated and absorbed in the tertiary butyl alcohol aqueous solution in the reaction vessel 6. Reaction vessel 6
If there is a catalyst therein, the absorbed isobutylene undergoes a hydration reaction with water to produce tertiary butyl alcohol. At this time, the target cold heat is generated by the latent heat of vaporization of isobutylene taken away in the storage means 5.

[0024]

Therefore, as is apparent from the above description, according to the chemical cold heat generating method and the apparatus thereof of the present invention, the following remarkable effects can be obtained due to the structural characteristics.

(1) Since the endothermic reaction temperature is relatively low, low quality exhaust heat can be easily utilized.

(2) As the cooling temperature, the ambient temperature can be used as it is.

(3) No compressor is required to utilize the high saturated vapor pressure generated during the production of isobutylene gas as a pressure source.

(4) From the above points, it is possible to provide an economical chemical heat pump having a simple system configuration.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of a chemical heat generation method according to an embodiment of the present invention and a cold heat generation system of an apparatus for carrying out the method.

First, the chemical cold heat generator of the present embodiment is
As the reaction system, an isobutylene / water / tertiary butyl alcohol reaction system has been found and used.

As described above, in the chemical cold heat generator such as the device of the present invention, the equilibrium temperature is close to room temperature,
In addition, it is essentially required that side reactions hardly occur and reversible reactions are possible. First, the reaction system of this embodiment is represented by the following formula (2), for example, as described above.

[0032]

[Equation 2]

The reaction system of the apparatus of the present invention represented by the above formula (2) has an equilibrium temperature of 56.0 ° C. and reversibly reacts in the presence of a catalyst without side reactions. In addition, isobutylene has a saturated vapor pressure of 20 from the results that have already been studied for high temperature parts.
2.6 atm at ℃, which is considerably higher than the other two components (alcohol and water) after decomposition, so no pressure source is required and it is very easy to separate, so it is suitable for use as a refrigerant for cold heat generation. Is.

In the figure, first, reference numeral 3 is liquefied isobutylene (C ₄
H ₈ ) is housed in the isobutylene cylinder, and the isobutylene cylinder 3 is connected to the storage container 5 via a first pipe 13 provided with a first valve 1 on the way. Then, when the first valve 1 is opened, the liquefied isobutylene housed inside is supplied into the storage container 5 through the first pipe 13 and stored in a high pressure state.

On the other hand, the storage container 5 has a second
It is connected to the reaction vessel 6 through a second pipe 14 provided with a valve 2, and when the second valve 2 is opened, the pressure in the storage vessel 5 is reduced and the evaporated isobutylene gas is transferred to the second vessel. It is adapted to be supplied into the reaction vessel 6 through the pipe 14. Then, a predetermined amount of tertiary butyl alcohol (CH ₃ ) ₃ COH aqueous solution is stored in the reaction vessel 6, absorbs the isobutylene gas supplied from the storage vessel 5 and the presence of a catalyst (for example, a cation exchange resin). The isobutylene gas C ₄ H absorbed by
₈ reacts with water H ₂ O (hydration reaction) to give tert-butyl alcohol
(CH ₃ ) ₃ COH is produced. The generated tertiary butyl alcohol aqueous solution is taken out from the take-out port 15 and sampled if necessary.

In this case, in constructing an actual refrigerating apparatus, the tertiary butyl alcohol aqueous solution produced by the hydration reaction is sent to, for example, a separator to cause an alcoholysis reaction under a predetermined temperature condition. , Isobutylene, alcohol and water are evaporated. Then, it may be configured to be used in place of the isobutylene cylinder 3 by condensing in a low-temperature condenser to separate alcohol and water, and extracting only isobutylene gas having a high saturated vapor pressure and cooling and liquefying it.

Further, reference numerals 11 and 12 are thermo-containers (constant temperature baths) for maintaining the storage container and the reaction container 6 at a predetermined temperature, respectively. Predetermined heat medium in the thermo containers 11 and 12
It is soaked in (eg water). Also, reference numerals 7 and 8
Is a pressure gauge for measuring the pressure in each of the containers 5 and 6 described above.
Is a thermocouple for measuring the reaction temperature.

Therefore, for example, in the above-mentioned configuration, while a predetermined amount of liquefied isobutylene from the isobutylene cylinder 3 is sampled and placed in the storage container 5 as described above, the reaction container 6 is further charged with a tertiary butyl alcohol aqueous solution. Here, when the open / close valve 2 between them is opened, the liquefied isobutylene in the storage container 5 evaporates and is absorbed in the tertiary butyl alcohol aqueous solution in the reaction container 6. When there is a catalyst in the reaction vessel 6, the absorbed isobutylene undergoes a hydration reaction with water to produce tertiary butyl alcohol.
At this time, the target cold heat is generated by the latent heat of vaporization of isobutylene taken in the storage container 5.

Next, in order to confirm the effectiveness of the above reaction system,
An experiment was conducted to determine the absorption rate of isobutylene in an aqueous tertiary butyl alcohol solution.

First, FIG. 2 shows the measurement results of an experiment in which the absorption rate of isobutylene gas was determined without using a catalyst with respect to the concentration of the tertiary butyl alcohol aqueous solution in the reaction vessel 6. The vertical axis represents the mole fraction of isobutylene in the tertiary butyl alcohol aqueous solution. The curve in the figure is based on the mass transfer equation shown in the following equation (3).

N ′ = Ky ′ · A (y−y ′) [kmol / h] (3) Represents a gas phase concentration that is in equilibrium with the concentration of the liquid phase body at a certain moment.
The activity coefficient required to obtain y ′ was estimated using the UNIFAC method, which is one of the group contribution methods.
Similarly, y, which represents the gas phase concentration at a certain moment, is UNIFA
The gas phase concentration at the time of gas-liquid equilibrium obtained by the C method (a method of estimating the activity of the target component from the statistical parameters for each functional group group by considering the target component as an aggregate of functional group) was used. Using these numbers, the Ky'.A that appeared to be the best fit to the plot was given and the curve was drawn.

Further, FIG. 3 shows the result of calculation of the coefficient of performance (COP) of this chemical heat pump. On the endothermic reaction side, the condenser temperature was 40 ° C., the vapor pressure of isobutylene gas was 3.5 atm, and the liquefaction temperature was 30 ° C. On the exothermic reaction side, the temperature and vapor pressure of isobutylene gas were 5 ° C.
The COP was determined when the absorption temperature of isobutylene was changed to 20 to 40 with the decomposition temperature of tert-butyl alcohol on the separator 1 side as a parameter being 1.6 atm.

COP was calculated by dividing the cold heat Qe in the evaporator 5 parts obtained during the isobutylene absorption reaction by the heat quantity Qs required for the tertiary butyl alcohol decomposition reaction on the separator 1 side.

As a result, when the decomposition temperature of tert-butyl alcohol was 70 ° C. and the absorption temperature of isobutylene was 20 ° C., C
OP became a practical value of 0.64.

[Brief description of drawings]

FIG. 1 is a system diagram showing a chemical cold heat generating method according to an embodiment of the present invention and a configuration of an apparatus for carrying out the method.

FIG. 2 is a characteristic diagram of a mole fraction showing an absorption rate of isobutylene in the method and the apparatus.

FIG. 3 is a characteristic diagram showing a coefficient of performance (COP) with respect to an operating temperature of the method and apparatus.

FIG. 4 is a schematic view showing the principle of heat absorption and heat generation of a conventional chemical refrigeration system.

FIG. 5 is a schematic diagram showing a relationship between pressure and temperature in the same apparatus.

[Explanation of symbols]

Reference numeral 1 is a first valve, 2 is a second valve, 3 is an isobutylene cylinder, 5 is a storage container, and 6 is a reaction container.

Claims (2)

(57) [Claims] 1. A chemical cold heat generation method, wherein cold heat is obtained by evaporating liquefied isobutylene and then absorbing it in a tertiary butyl alcohol aqueous solution. 2. A storage means (5) for storing liquefied isobutylene supplied from a predetermined supply means and a storage means (5) communicated with the storage means (5) through an opening / closing valve (2), and a predetermined amount of a third portion Reaction container (6) containing butyl alcohol aqueous solution
And opening the on-off valve (2) to evaporate the isobutylene stored in the storage means (5) and absorb it in the tertiary butyl alcohol aqueous solution in the reaction vessel (6) to cool the heat. A chemical cold heat generator that can be obtained.