JP2775601B2 - Absorption liquid for absorption refrigerator and transfer device for this absorption liquid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention, absorption liquid used in the absorption chiller or absorption chiller heater, particularly, as a component of the absorbent, by the specific gravity is added heavy fluorine-based alcohol than the absorption liquid, Absorbing liquid for absorption refrigerator or absorption chiller / heater (hereinafter, simply referred to as absorption liquid for absorption refrigerator) and additive (absorption accelerator) added to promote absorption of water vapor by the absorption liquid. And a device for transferring the additive without retaining the additive.

[0002]

2. Description of the Related Art FIG. 3 shows a general absorption refrigerator. Conventionally, in an absorption refrigerator, a LiBr aqueous solution 10 is used as an absorption liquid. Further, the refrigerant absorption rate (heat transmission rate) of the absorber 12 of the absorption refrigerator is the smallest among the heat exchangers constituting the absorption refrigerator, and requires the largest heat transfer area. Therefore, conventionally, for example, 2-ethylhexyl alcohol (octyl alcohol, boiling point: 187 ° C.) or the like is added as an absorption-promoting additive, thereby increasing the heat transmission coefficient by circulating use, and reducing the size of the absorber. However, octyl alcohol flows out from the lower part of the absorber together with the solution, flows to the regenerator via the solution heat exchanger, is condensed in the condenser together with most of the refrigerant vapor, and is conveyed to the evaporator. And there it evaporates again with the refrigerant,
It reaches the absorber and condenses on the surface of the absorbing liquid, exhibiting an absorption promoting effect. However, the surfactant in contact with the absorbent is
A high-concentration inorganic aqueous solution in the absorbing solution is extracted, and the viscosity of the solution itself is very large. That is, octyl alcohol has a problem that when it comes into contact with a solution, it becomes high in viscosity and easily stays in the absorption refrigerator. In addition, since the surfactant easily stays in the condenser, a bypass circuit connecting the condenser and the absorber may be provided. However, in order to efficiently separate the surfactant, a large amount of surfactant is required. Agent is required. This has the disadvantage that the cycle efficiency is reduced and the incidental costs are also increased.

On the other hand, a regenerator 16, a condenser 18, and an evaporator 20, which are heat exchangers other than the absorber, are respectively provided with boiling evaporators,
Due to the heat transfer mechanism such as condensation heat transfer and film evaporation, the heat transmission rate is increased from the device design to almost the limit. Therefore, as a way to reduce the size of the absorption refrigerator, the key is to reduce the heat transfer area of the absorber, and the search and development of new additives for promoting absorption have been a challenge. In addition, absorption enhancing additives include:
There are many alcohol-based organic compounds having a relatively low specific gravity, and due to their properties (lipophilicity, etc.), they are dissolved in the LiBr aqueous solution by the amount corresponding to the solubility, and the remainder floats on the surface of the LiBr aqueous solution. Therefore, when supplying the absorbent into the regenerator, the absorption accelerator remains on the surface of the absorbent, and only the aqueous LiBr solution is supplied.
Reference numeral 14 denotes an absorption accelerator on the surface of the absorbing solution.

Japanese Patent Publication No. 52-48710 discloses an absorbent comprising a brine aqueous solution and a fluoroalcohol for increasing the absorption rate of the brine aqueous solution, which has excellent thermal stability and an increased absorption rate of the absorbing solution. An agent composition is described. Japanese Patent Publication No. 7-6704 discloses that an absorption solution composed of an aqueous solution containing an alkali halide as a main component contains 2-octanol, 1-heptanol, 2-methyl-1-hexanol, 1-hexanol as an absorption promoter. An absorption liquid of an absorption refrigerator in which an alcohol-based saturated hydrocarbon having a boiling point of 155 to 180 ° C. such as hexanol is added so that the retention of the absorption liquid hardly occurs.

[0005]

However, since the specific gravity of these alcohol-based saturated hydrocarbons is lower than the specific gravity of the absorbing solution, they float on the surface of the absorbing solution, and therefore, as in the case of 2-ethylhexyl alcohol described above. When the absorption liquid and the absorption promoter are sent, there is a problem that only the absorption liquid is sent. In other words, the alcohols described in the above two publications have a lower specific gravity than the absorbing liquid, and float on the surface of the absorbing liquid in the absorbing liquid pool of the absorber after absorbing the refrigerant vapor (the dispersibility of the alcohol decreases). When the absorption liquid is sent into the regenerator by the suction force of the solution pump during startup or operation of the refrigerator, there is a problem that only the absorption liquid is sent. Accordingly, in the long-term operation, the amount of alcohol remaining in the absorption liquid reservoir increases, so that there is a problem in that the absorption promotion effect at the time of refrigerant vapor absorption decreases. In addition, a large amount of alcohol must be added or added to maintain the absorption promoting effect. The present inventor has conducted intensive studies in order to solve the above problems, and as a result, by adding a fluorinated alcohol to an absorbing solution mainly composed of LiBr and water, the water absorbing performance of the absorbing solution was It was found that the fluorinated alcohol floated on the surface of the absorbent and a part of the fluoroalcohol sank into the absorbent. In addition, the present inventor has found that by adding a hydrocarbon alcohol having a boiling point of 190 to 215 ° C to the absorbing solution, the water vapor absorbing performance of the absorbing solution is promoted.

The present invention has been made in view of the above-mentioned points, and has been made based on the above findings. It is an object of the present invention to promote the water vapor absorption performance of an absorption liquid for an absorption refrigerator, and to provide a heat transfer coefficient by a circulation action. And the size of the absorber for the absorption refrigerator can be reduced. Another object of the present invention is to provide a device for transferring an absorbing liquid that prevents only the absorbing liquid from being sent when an additive (absorption promoter) is added, and prevents the additive from staying. Is to provide. As described above, in the present invention, when the absorbing liquid is supplied to the regenerator, only the absorbing liquid is prevented from being sent by adding the alcohol having a higher specific gravity than the absorbing liquid to the absorbing liquid. Moreover, the water vapor absorbing performance of the absorbing liquid can be promoted. Furthermore, the dispersibility of the absorbing liquid and the fluorinated alcohol to be supplied to the regenerator from the absorbing liquid pool can be improved by adopting an apparatus structure as shown in FIG. 2 described later, and it is not necessary to add or add a large amount of alcohol. It is characterized by:

[0007]

To achieve SUMMARY and effects of the Invention The above object, the absorption chiller absorbing solution of the present invention, the alkaline absorbent solution mainly composed of a lithium bromide and water, the
Specific gravity than the heavier alkaline absorbent solution fluoric alcohol
It is configured to be added. Examples of the fluorinated alcohol include 2- (perfluorobutyl) ethanol (specific gravity 1.590), 2- (perfluorohexyl) ethanol, 2- (perfluoro-3-methylbutyl) ethanol, and 2- (perfluoro-5-ethanol). Methylhexyl)
Ethanol (specific gravity 1.762 or more), 3-perfluorobutyl-2-propen-1-ol, 3-perfluorohexyl-2-propen-1-ol, 6- (perfluorohexyl) hexanol, 1H, 1H, At least one alcohol selected from the group consisting of 3H-tetrafluoropropanol is used.

When these alcohols are added to the absorbing solution, an interface disturbance phenomenon is developed, and as shown in FIG. 1, these alcohols, especially the fluorinated alcohol 22, have a higher specific gravity than the dilute absorbing solution. A part of the fluorinated alcohol 2 is settled in the absorbing solution 10 mainly composed of an aqueous solution of LiBr and serves as an absorption accelerator (additive).
2 and the absorbing liquid 10 are sent together. It is more convenient to select a rare absorbing liquid having a high specific gravity and a thick absorbing liquid having a low specific gravity. The addition amount of the fluorinated alcohol is 0.001 to 5% by weight, preferably 0.01 to 3% by weight, and more preferably 0.05 to 2% by weight. When the addition amount of the fluorinated alcohol is less than these ranges,
It becomes insufficient to lower the surface tension of the absorbing solution, and there is a tendency that the interface disturbance phenomenon does not occur.On the other hand, if it exceeds these ranges, it affects the vapor pressure of the absorbing solution and increases the vapor pressure, There is a tendency that the water vapor absorption performance of the absorbent is reduced.

[0009] The upper Symbol absorption refrigerator absorption liquid, usually lithium hydroxide (LiOH) is added as a corrosion inhibitor.

FIG. 2 shows an embodiment of the absorption liquid transfer device for an absorption refrigerator according to the present invention. FIG. 2 is a detailed view around the bottom of the absorber in FIG. The transfer device of the present invention comprises a solution pump 3 for circulating an absorption liquid for an absorption refrigerator.
The suction pipe 32 is disposed so as to penetrate the bottom of the absorber 12 of the absorption refrigerator so that the suction port 34 at the upper end is located in the absorption liquid 10, and the suction is located near the bottom in the absorber 12. Tube 3
2, the additive (absorption enhancer) suction holes 36 to prevent stagnation of the additive was aspirated from the primarily absorbing liquid specific gravity additive (absorption enhancer) is provided, intake of the suction tube 32 the upper end
The area _{S A} of引口34, the total area _{S B} of the additive suction holes 36
The ratio S _{A /} S _B is, the liquid composition ratio of the absorption liquid to additives and
From the range of 19 to 99999,
Additives have settled mainly sucked from the additive suction holes, the ratio mainly of additives from the suction port of the upper end of the suction pipe
The absorption liquid having a light weight is sucked, and the dispersibility of the additive in the absorption liquid is improved. In this case, since the additive is mainly sucked from the additive suction hole 36, the absorption is performed.
The stagnation of the additive having a higher specific gravity than the liquid can be prevented. The upper limit h ₁ of the height of the suction pipe 32 in the absorber vessel may be lower than the height H ₁ to the absorption liquid surface of the reservoir absorption liquid,
The lower limit h _2, if higher than the bottom reservoir absorbing fluid, there is no particular problem. In addition, the shape of the suction tube 32 may be a cylindrical shape or a square tube shape, and is not particularly limited. As described above, the area S _A of the suction port 34 at the upper end of the suction tube 32 and the additive suction hole 36
The ratio _{n =} S A / _{S B} of the total area _{S B} of 19 to 9999
9 range. That is, n may be in the range of the liquid composition ratio between the absorbing liquid and the fluorinated alcohol. n = S _A : S _B = 99.999: 0.001 n = S _A : S _B = 95: 5 (assuming that the absorption liquid is 100) That is, the range of 19 <S _A / S _B <99999 is satisfied. Desirably the minimum, more desirably the maximum. The shape and number of the additive suction holes 36 are not particularly limited, but it is desirable to provide a plurality of additive suction holes 36 at the same height.

[0011]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following Examples and can be carried out with appropriate modifications. It is. Comparative Example 1 An aqueous solution containing 64 % by weight of LiBr was prepared, and 0.10% by weight of 2-ethylhexyl alcohol (octyl alcohol) was added to this aqueous solution to prepare a sample absorbing solution, and the water vapor absorption was measured. Table 1 shows the results. In Table 1, the water vapor absorption amount is represented by an absorption amount ratio, and the value in Comparative Example 1 is set to 1.0 to facilitate comparison with the embodiment.
It is displayed as 0.

[0012]

[Table 1]

Examples 1 and 2 An aqueous solution containing 64 % by weight of LiBr was prepared. As shown in Table 1, a fluorine-based alcohol and / or a hydrocarbon-based alcohol was added to this aqueous solution to prepare sample absorbing solutions, and the amount of water vapor absorption of each sample absorbing solution was measured. Table 1 shows the evaluation results. From Table 1, the absorption solution obtained by adding a fluorine-based alcohol in aqueous LiBr solution is found to promote water vapor absorption performance.

[0014]

As described above, the present invention has the following effects. (1) By adding a fluorinated alcohol having a higher specific gravity than the absorption liquid as an absorption accelerator (additive) to an absorption liquid containing LiBr and water as main components, an interface disturbance phenomenon is developed and the absorption liquid Promotes the water vapor absorption performance, increases the heat transmission rate by the circulation function, and makes it possible to reduce the size of the absorber for the absorption refrigerator. (2) When a fluorine-based alcohol having a higher specific gravity than the absorption liquid is added to the absorption liquid as an absorption promoter, a part of the absorption promoter sinks in the absorption liquid, and the absorption promoter is supplied when the absorption liquid is supplied. By remaining on the surface of the absorbing liquid, it is possible to prevent the supply of only the LiBr aqueous solution. (3) In the absorption liquid transfer device of the present invention, the additive (absorption accelerator) having a higher specific gravity than the absorption liquid is mainly sucked from the additive suction hole, so that when the additive (absorption accelerator) is added, In addition, it is possible to prevent only the absorbing liquid having a specific gravity lower than that of the additive from being sent, prevent the additive from staying therein, and improve the dispersibility of the additive in the absorbing liquid.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an example of an absorption refrigerator showing a case where the absorption liquid for an absorption refrigerator of the present invention is used.

FIG. 2 is an enlarged detail view showing the area around the bottom of the absorber in FIG. 1;

FIG. 3 is a system diagram of an absorption refrigerator showing a case where a conventional absorption liquid for an absorption refrigerator is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Absorbent liquid 12 Absorber 14 Absorption promoter 16 Regenerator 18 Condenser 20 Evaporator 22 Fluorinated alcohol (absorption promoter, additive) 30 Solution pump 32 Suction pipe 34 Suction port 36 Additive suction hole

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Akihiro Murakami 1-1, Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries, Ltd. Akashi Plant (72) Inventor Kunihiko Nakajima 1000, Aoji-cho, Kusatsu-shi, Shiga (56) References JP-A-49-101949 (JP, A) JP-A-1-184371 (JP, A) JP-A-58-219938 (JP, A) JP-B-52-48710 (JP, B2)

Claims (6)

(57) [Claims] 1. An absorption liquid for an absorption refrigerator, wherein a fluorine-based alcohol having a higher specific gravity than the alkaline absorption liquid is added to an alkaline absorption liquid containing lithium bromide and water as main components. 2. The fluorinated alcohol is 2- (perfluorobutyl) ethanol, 2- (perfluorohexyl) ethanol, 2- (perfluoro-3-methylbutyl) ethanol, or 2- (perfluoro-5-methylhexyl). ) From ethanol, 3-perfluorobutyl-2-propen-1-ol, 3-perfluorohexyl-2-propen-1-ol, 6- (perfluorohexyl) hexanol, 1H, 1H, 3H-tetrafluoropropanol 2. The absorption liquid for an absorption refrigerator according to claim 1, wherein the absorption liquid is at least one alcohol selected from the group consisting of: 3. The amount of the fluorine-based alcohol added is 0.0
3. The absorption liquid for an absorption refrigerator according to claim 1, wherein the amount is from 01 to 5% by weight. 4. The absorption liquid for an absorption refrigerator according to claim 1, wherein lithium hydroxide is added as a corrosion inhibitor. 5. A solution pump for circulating an absorption liquid for an absorption refrigerator.
Through the bottom of the absorber of the absorption refrigerator
Is arranged so that the suction port of
The suction tube located near the bottom of theRatio than absorption liquid
HeavyTo prevent additives from staying by sucking additives
The additive suction hole ofSuction port area S at top of suction tube
_A And the total area S of the additive suction holes _B Ratio S _A / S _B But,
From the range of the liquid composition ratio of the absorbing solution to the additive, from 19 to 9
In the range of 9999,Additives that have settled
Suction is mainly performed from the additive suction hole, and the upper end of the suction tube is
Mainly from the suction portLighter specific gravity than additiveAspirate absorbing liquid
And improve the dispersibility of the additive in the absorbing solution.
An absorption liquid transfer device for an absorption refrigerator. 6. The absorption liquid transfer device for an absorption refrigerator according to claim 5, wherein a plurality of additive suction holes are provided at the same height.