JP2556222B2 - Chemical refrigeration equipment - 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 refrigerating apparatus which realizes a refrigerating function by 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 any of the reaction systems of the above-mentioned various candidate substances including the system is examined as a cooling system, the equilibrium temperature is higher than room temperature, and side reactions easily occur and the efficiency is high. There is a problem in that it is bad and the device becomes complicated, and there is no effective report as an air conditioning system at present.

[0014]

Claims 1 and 2 of the present application
The inventions described have been made for the purpose of solving the above conventional problems, and are configured as follows.

(1) Structure of the Invention According to Claim 1 In the chemical refrigeration apparatus of the invention according to claim 1, for example, as shown in FIG. 1, a tertiary butyl alcohol aqueous solution is heated to generate vapor containing isobutylene. Separator 1
And a condenser 2 for extracting only isobutylene gas having a high saturated vapor pressure by condensing and separating alcohol and water from the vapor containing isobutylene supplied from the separator 1.
A receiver 3 that cools the isobutylene gas supplied from the condenser 2 at a low temperature and stores it as a liquefied gas; a cooling evaporator 5 that introduces and decompresses the liquefied isobutylene gas stored in the receiver 3 to evaporate the liquefied isobutylene gas; An absorber 6 that absorbs the isobutylene gas that has been vaporized by the evaporator 5 to cause a hydration reaction to generate tertiary butyl alcohol, and a supply means 7 that supplies the tertiary butyl alcohol generated by the absorber 6 to the separator 1.
It is comprised including.

(2) Structure of the Invention According to Claim 2 The chemical refrigeration apparatus of the invention according to Claim 2 is such that, as illustrated in FIG.
A separator 1 which generates steam containing isobutylene by heating to a temperature of ℃ to 90 ℃, and alcohol and water are condensed and separated from the steam containing isobutylene supplied from the separator 1 and saturated at 2 to 4 atmospheres. The condenser 2 for extracting only isobutylene gas having a high vapor pressure and the isobutylene gas supplied from the condenser 2 are heated at 20 ° C to 30 ° C.
A receiver 3 that cools at a low temperature and stores as liquefied gas,
A liquefied isobutylene gas stored in the receiver 3 is introduced, and a cooling evaporator 5 for reducing the pressure to 1.5 atm to 2 atm to evaporate, and a low temperature isobutylene gas of 5 ° C. to 10 ° C. evaporated and vaporized by the evaporator 5. It is configured to include an absorber 6 that absorbs hydrogen and causes a hydration reaction to generate tertiary butyl alcohol, and a supply unit 7 that supplies the tertiary butyl alcohol generated by the absorber 6 to the separator 1.

[0017]

The chemical refrigerating apparatus of the inventions according to claims 1 and 2 of the present invention are configured as described above, respectively.
The following operations are performed corresponding to the respective configurations.

(1) Action of the chemical refrigeration system of the invention described in claim 1 In the chemical refrigeration system of the invention described in claim 1, as is clear from the above description, the reaction system is first isobutylene / water / second. We have newly found and used the 3-butyl alcohol reaction system.

In a chemical refrigeration system such as the device of the present invention,
It is essentially required that the above-mentioned equilibrium temperature is close to room temperature and that side reactions are less likely to occur and reversible reactions are possible.

[0020]

[Equation 2]

The reaction system of the apparatus of the present invention represented by the above formula (2), for example, has an equilibrium temperature of about 56.0 ° C. and reacts reversibly without side reaction in the presence of a catalyst. In addition, from the results that have already been researched on 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 that it is easy to separate, so that it can be used as a refrigerant for cold heat generation. Suitable to use.

Therefore, in the apparatus of the present invention, first, the tert-butyl alcohol aqueous solution introduced into the separator 1 is heated to a predetermined temperature to generate vapor containing isobutylene gas, and then in the condenser (condenser) 2. Isobutylene gas is separated from alcohol and water. Then, the separated high-pressure isobutylene gas is cooled at a predetermined temperature and stored as liquefied gas in the low-temperature receiver 3 which is a storage container.

The isobutylene gas liquefied in this way is then evaporated by depressurizing it in the evaporator 5 and sent to the absorber 6 which is a reaction vessel, whereby a hydration reaction occurs and tertiary butyl alcohol is produced, and further isobutylene gas is produced. Absorbs. At this time, the isobutylene in the evaporator 5, which is the storage container, has a suitable low temperature as a cold refrigerant, and the cold heat for freezing is obtained by recovering this cold heat using a heat exchanger.

(2) Action of the chemical refrigeration system of the invention described in claim 2 In the chemical refrigeration system of the invention described in claim 2, as is clear from the above description, the reaction is the same as in the invention described in claim 1. As a system, first, an isobutylene / water / tertiary butyl alcohol reaction system is newly found and used.

In the chemical refrigerating apparatus such as the apparatus of the present invention, it is essentially required that the equilibrium temperature is close to room temperature as described above and that side reactions are less likely to occur and reversible reactions are possible.

[0026]

[Equation 2]

The reaction system of the apparatus of the present invention represented by the above formula (2), for example, has an equilibrium temperature of 56.0 ° C. and reacts reversibly in the presence of a catalyst without side reactions. In addition, from the results that have already been researched on 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 that it is easy to separate, so that it can be used as a refrigerant for cold heat generation. Suitable to use.

Therefore, in the apparatus of the present invention, first, the tert-butyl alcohol aqueous solution introduced into the separator 1 is heated to 70 ° C.
It is heated to 90 ° C. to generate a vapor containing isobutylene gas, and then a condenser (condenser) 2 separates the isobutylene gas from alcohol and water. Thereafter, the separated high-pressure (2-4 atm) isobutylene gas is cooled at 20-30 ° C. and stored in the receiver 3 as a storage container as a liquefied gas.

The isobutylene gas liquefied in this way is then evaporated under reduced pressure to 1.5 to 2 atm by the evaporator 5 and sent to the absorber 6 which is a reaction vessel to cause a hydration reaction to produce tert-butyl alcohol. Further, it absorbs isobutylene gas. At this time, the isobutylene in the evaporator 5 serving as the isobutylene storage container has a low temperature of about 5 to 10 ° C., which is suitable as a cold refrigerant, and the cold heat for freezing can be obtained by recovering this cold heat using a heat exchanger.

[0030]

As is apparent from the above description, the chemical refrigerating apparatus of the present invention can obtain the following remarkable effects due to its structural characteristics.

(1) Since the endothermic reaction temperature is as low as 70 to 90 ° C., low quality exhaust heat can be easily utilized.

(2) As the cooling temperature, the ambient temperature (20 to
30 ° C) 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.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the structure of an absorption / heating system of a chemical refrigeration system according to an embodiment of the present invention.

First, the chemical refrigerating apparatus comprises a separator 1,
The endothermic reaction operation system consisting of the condenser 2 and the receiver 3, the evaporator 5, and the exothermic reaction operation system consisting of the absorber 6 are connected endlessly by a refrigerant pipe as shown in the figure to form a refrigeration cycle.

In the chemical refrigeration system of this embodiment,
As the reaction system, an isobutylene / water / tertiary butyl alcohol reaction system has been found and used.

As described above, in the chemical refrigeration apparatus such as the apparatus of the present invention, it is essentially required that the equilibrium temperature is close to room temperature and that a side reaction hardly occurs and a reversible reaction is possible. . First, the reaction system of the present embodiment is represented by, for example, the following formula (2).

[0039]

[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. Also, from the results that have already been studied for high temperature parts, isobutylene has a saturated vapor pressure of 20 ° C.
Since 2.6 atm is considerably higher than the other two components (alcohol and water), a pressure source is unnecessary and it is very easy to separate, so it is suitable for use as a refrigerant for cold heat generation.

First, the separator 1 is, for example, a pump 7
The liquid refrigerant (tertiary butyl alcohol aqueous solution) having a high alcohol concentration supplied from the absorber 6 side via, for example, Ts = 70 ° C. by a heat exchanger 9 equipped with an external heater.
After being heated to a temperature of .about.90.degree. C., it is introduced to cause an alcohol decomposition reaction (endothermic reaction), thereby evaporating and vaporizing each of the three components of water, alcohol and isobutylene.

The vaporized refrigerant consisting of the three components of vaporized water, alcohol and isobutylene is then supplied to the condenser 2 and condensed at a relatively low temperature of, for example, temperature Tc = 40 ° C. Particularly, isobutylene gas having a high saturated vapor pressure is easily separated from water and alcohol.

The separated isobutylene gas
(Atmospheric pressure 3.5 atm) is further supplied to the receiver 3 and Tr =
It is cooled and liquefied at an ambient temperature of about 30 ° C. (heat radiation amount Qc). At this time, the pressure on the high pressure side is determined by the value of the temperature Tr of the receiver 3.

The isobutylene liquefied as described above is evaporated under reduced pressure through the low pressure evaporator 5 of about 1.6 atm by opening the valve 4, and then absorbed by the absorber 6 which is a hydration reaction container. On the other hand, the absorber 6 is supplied with the alcohol and water from which the isobutylene has been separated from the separator 1 side via the valve 8, and causes the vaporized isobutylene gas and the alcohol and water to undergo a hydration reaction. As a result, tert-butyl alcohol is produced, and further acts to effectively absorb the isobutylene gas. The calorific value Qa when absorbing the isobutylene gas is radiated to the outside.

As a result, the isobutylene in the evaporator 5 is Te = 5 ° C. due to the progress of the evaporation and absorption action.
The temperature becomes an optimum low temperature as a cooling medium for cooling at about 10 ° C., and the cooling heat can be effectively obtained by recovering the cooling heat using a heat exchanger.

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, 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 absorber 6 are shown in FIG.
Shown in 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 necessary to obtain y ′ is the UNIFAC method, which is one of the group contribution methods (think of the target component as an aggregate of functional group, and use the statistical parameters for each functional group to determine the activity of the target component. (How to estimate the amount)
It was estimated using. Similarly, for y representing the vapor phase concentration at a certain moment, the vapor phase concentration at the vapor-liquid equilibrium determined by the UNIFAC method 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 refrigeration circuit diagram showing a configuration of a chemical refrigeration apparatus according to an embodiment of the present invention.

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

FIG. 3 is a coefficient of performance for operating temperature of the device.
It is a characteristic view showing (COP).

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]

1 is a separator, 2 is a capacitor, 3 is a receiver, 5 is an evaporator, and 6 is an absorber.

Claims (2)

(57) [Claims] 1. A separator (1) for heating a tertiary butyl alcohol aqueous solution to generate vapor containing isobutylene.
And a condenser for taking out only isobutylene gas having a high saturated vapor pressure by condensing and separating alcohol and water from the vapor containing isobutylene supplied from the separator (1).
(2) and a receiver that cools the isobutylene gas supplied from the condenser (2) at low temperature and stores it as liquefied gas
(3) and a cooling evaporator for introducing and reducing the pressure of the liquefied isobutylene gas stored in the receiver (3) to evaporate
(5), an absorber (6) which absorbs the isobutylene gas vaporized and vaporized by the evaporator (5) to cause a hydration reaction to generate tertiary butyl alcohol, and the absorber (6)
The tert-butyl alcohol produced in (6) is used as the separator
A chemical refrigeration system comprising: a supply means (7) for supplying (1). 2. A tert-butyl alcohol aqueous solution at 70 ° C.
A separator (1) which is heated to a temperature of 90 ° C. to generate vapor containing isobutylene, and alcohol and water are condensed and separated from the vapor containing isobutylene supplied from the separator (1) to 2 atm to 4 atm. Of a condenser (2) for taking out only isobutylene gas having a high saturated vapor pressure and isobutylene gas supplied from the condenser (2) at 20 ° C to 3 ° C.
Receiver that cools at low temperature of 0 ℃ and stores as liquefied gas
(3), a cooling evaporator (5) for introducing and liquefying the liquefied isobutylene gas stored in the receiver (3) by reducing the pressure to 1.5 atm to 2 atm, and evaporating by the evaporator (5) An absorber (6) that absorbs low-temperature isobutylene gas at 5 ° C to 10 ° C to cause a hydration reaction to produce tertiary butyl alcohol, and tertiary butyl alcohol produced by the absorber (6) are added to the separator (1). A chemical refrigeration system comprising a supply means (7) for supplying.