JP2000171121A - Absorption refrigerating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the cooling of the product or the intermediate products obtained by a chemical plant or the like to be cooled, too, not to speak of the heating of the tower bottom, using the tower-head vapor or the like of a chemical plant as a heat source. SOLUTION: This absorption refrigerating machine is equipped with a high- temperature evaporator 7 which evaporates a refrigerant, using the tower-head vapor or the like of a chemical plant as a heat source, a high-temperature absorber 11 which makes absorbing solution absorb the refrigerant vapor supplied from this high- temperature evaporator, a low-temperature evaporator 5 which cools the fluid to be cooled with the heat of evaporation of the refrigerant, a low-temperature absorber 9 which makes the absorbing solution absorb the refrigerant vapor supplied from this low-temperature evaporator, a regenerator 1 which heats the absorbing solution with the vapor of the tower head or the like and evaporates and separates the refrigerant and circulates and supplies the absorbing solution where the refrigerant is in low concentration in order of the high-temperature absorber 11 and the low-temperature absorber 9, and condenser 3 which cools and condenses the refrigerant vapor supplied from this regenerator and supplies it to the high-temperature and low-temperature evaporators.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an absorption refrigerator driven by using exhaust heat as a heat source.

[0002]

2. Description of the Related Art A conventional absorption chiller, which is installed in a chemical plant or the like and is driven by using exhaust heat from the plant, is intended for heating and requires cooling of products and intermediate products. In some cases, a refrigerator was separately installed.

[0003]

Therefore, in the case where the heating and cooling functions are combined, a large installation space is conventionally required and the piping thereof is complicated. Had been an issue.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems in the prior art, the present invention provides a high-temperature evaporator to which a heat source fluid is supplied to evaporate a refrigerant, and a refrigerant vapor supplied from the high-temperature evaporator to an absorbing liquid. A low-temperature evaporator that cools the fluid to be cooled with the heat of evaporation of the refrigerant, a low-temperature absorber that absorbs the refrigerant vapor supplied from the low-temperature evaporator into the absorbent, and heats the absorbent. A regenerator that evaporates and separates the refrigerant and circulates the absorbent in which the refrigerant has become low in concentration in the order of a high-temperature absorber and a low-temperature absorber, and cools and condenses the refrigerant vapor supplied from this regenerator. And a condenser for supplying to the low-temperature evaporator, and an absorption refrigerator having a first configuration,

[0005] In the absorption refrigerator of the first configuration,
An absorption liquid supplied from the high-temperature absorber to the low-temperature absorber, a low-temperature heat exchanger in which heat exchange is performed between the absorption liquid returned from the low-temperature absorber to the regenerator, and an absorption liquid supplied from the high-temperature absorber,
An absorption refrigerator having a second configuration in which a high-temperature heat exchanger for exchanging heat with the absorption liquid supplied from the regenerator to the high-temperature absorber is provided;

[0006] In the absorption refrigerator of the first or second configuration, a pipe line is formed so that the absorption liquid having absorbed the refrigerant vapor in the high-temperature absorber can flow into the regenerator, and the absorption liquid is removed from the low-temperature absorber. An absorption refrigerator having a third configuration in which a valve is provided in a pipeline returning to the regenerator and a pipeline for flowing the refrigerant liquid from the condenser to the low-temperature evaporator;

[0007] In the absorption refrigerator of the third configuration,
A pipe valve that returns the absorbent from the low-temperature absorber to the regenerator
A first valve is provided downstream of the low-temperature heat exchanger, and a valve (hereinafter, referred to as a first valve) is provided downstream of the high-temperature heat exchanger in a pipeline for supplying the low-temperature regenerator with the absorbing liquid having absorbed the refrigerant vapor by the high-temperature absorber. , A second valve) and a line between the low temperature heat exchanger and the first valve and a line between the high temperature heat exchanger and the second valve. An absorption refrigerator having a fourth configuration connected by a pipeline;

In the absorption refrigerating machine of any of the first to fourth configurations, the fluid to be cooled is supplied to the low-temperature absorber based on the outlet-side temperature of the low-temperature evaporator or the temperature of the refrigerant in the low-temperature evaporator. An absorption refrigerator having a fifth configuration in which control means for controlling the flow rate of the absorption liquid is provided;

[0009] In the absorption refrigerator of any of the first to fifth configurations, based on the level of the refrigerant liquid in the low-temperature evaporator,
An absorption refrigerator having a sixth configuration in which control means for controlling the flow rate of the refrigerant liquid supplied from the condenser to the low-temperature evaporator is provided;

[0010] In the absorption refrigerator of any of the first to sixth configurations, based on the level of the absorbing liquid in the low-temperature absorber,
An absorption refrigerator having a seventh configuration in which control means for controlling the flow rate of the absorption liquid supplied from the low-temperature absorber to the regenerator is provided;

In the absorption refrigerating machine of any one of the first to seventh constructions, a pipe through which the cooling fluid flows is provided in parallel with the low-temperature absorber and the condenser, and the low-temperature absorption is performed based on the temperature of the fluid to be cooled. The flow rate of the cooling fluid supplied to the high temperature evaporator is controlled and supplied to the condenser based on the pressure or temperature of the refrigerant vapor generated in the high temperature evaporator or the inlet or outlet temperature of the fluid supplied to the high temperature absorber. An absorption refrigerator having an eighth configuration, wherein a control unit for controlling a flow rate of a cooling fluid to be provided is provided;

[0012] In the absorption refrigerator of any one of the first to eighth configurations, the absorption refrigerator having a ninth configuration in which a pipe is provided so that a refrigerant liquid can be supplied from a low-temperature evaporator to a high-temperature evaporator. When,

[0013] In the absorption chiller of the ninth configuration,
An absorption refrigerator having a tenth configuration in which control means for controlling supply of the refrigerant liquid from the low-temperature evaporator to the high-temperature evaporator is provided based on the amount of the refrigerant liquid in the low-temperature evaporator;

In the absorption refrigerator having any one of the first to tenth constitutions, the heat source fluid having completed the heating action in at least one of the regenerator and the high-temperature evaporator, and the heat source fluid supplied from the condenser to the high-temperature evaporator. And a heat exchanger for exchanging heat with the refrigerant liquid.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below in which water is used as a refrigerant and an aqueous solution of lithium bromide is used as an absorbing solution. Absorption refrigerating machine that obtains heat higher than the temperature to perform tower bottom heating and the like, and cools an appropriate fluid, for example, hexane produced in a chemical plant (hereinafter, referred to as a fluid to be cooled) to a predetermined temperature. This will be described using an example.

In FIG. 1, 1 is a regenerator having a heat transfer tube 2 inside, 3 is a condenser having a heat transfer tube 4 inside, 5 is a low-temperature evaporator having a heat transfer tube 6 inside, and 7 is a heat transfer tube. A high-temperature evaporator having a heat tube 8 therein; a low-temperature absorber 9 having a heat transfer tube 10 therein; a high-temperature absorber 11 having a heat transfer tube 12 therein; 13 and 14 low- and high-temperature heat exchangers; Fifteen, one
6, 17, 18 are valves, P1, P2, P3 are refrigerant pumps,
P4 and P5 are absorption liquid pumps, each of which is provided as shown in the figure to form a circulation path between the refrigerant and the absorption liquid.

Further, temperature sensors 19 and 20 are provided at the positions shown in FIG.
And the temperature of the hot water supplied to the heat transfer tube 12 can be detected.

In addition, flow control valves 21 and 22 are provided in each of the pipes connected to the heat transfer tubes 4 and 10 so that cooling water can be supplied to each of them independently.

The low-temperature evaporator 5 and the low-temperature absorber 9 include:
Liquid level sensors 23 and 24 are provided, respectively, so that the liquid level positions of the refrigerant liquid and the absorbing liquid can be respectively detected. Reference numeral 25 denotes a control unit including a microcomputer and the like.

The regenerator 1 has an overhead liquid of about 90 ° C. supplied from a chemical plant passed through an internal heat transfer tube 2 as a heat source, and contains a large amount of refrigerant water and is sprayed from above, ie, an absorbing liquid. The diluent is heated by the heat of the overhead vapor to separate the refrigerant vapor from the absorbent.

The refrigerant vapor separated in the regenerator 1 is supplied to the condenser 3
Then, heat is radiated to the cooling water flowing inside the heat transfer tube 4 and condensed and liquefied.

The refrigerant liquid radiated by radiating heat in the condenser 3 is supplied to the low-temperature evaporator 5 and the high-temperature evaporator 7 by the refrigerant pump P1.

The refrigerant liquid entering the high-temperature evaporator 7 is sprayed by a refrigerant pump P3 on a heat transfer tube 8 disposed therein, and takes heat of a high-temperature fluid flowing therein, for example, the above-mentioned vapor at the top. Evaporates and enters the high-temperature absorber 11.

The refrigerant vapor entering the high-temperature absorber 11 is supplied from the regenerator 1 by the absorption liquid pump P5 and sprayed from above, that is, the refrigerant is evaporated and separated by heating with the top vapor, and the absorption liquid concentration is increased. Is absorbed by the increased concentrated liquid, becomes an intermediate liquid, and is supplied to the lower low-temperature absorber 9 by the pressure difference and its own weight.

The absorption liquid (concentrated liquid) supplied from the regenerator 1 to the high-temperature absorber 11 and the absorption liquid (intermediate liquid) supplied from the high-temperature absorber 11 to the low-temperature absorber 9 are separated by a high-temperature heat exchanger. 1
Since heat is exchanged in 4 and the temperature of the absorbing liquid (concentrated liquid) entering the high-temperature absorber 11 is increased, the amount of hot water that is heated by the heat transfer tube 12 and extracted from the high-temperature absorber 11 can be increased.

That is, hot water controlled at a predetermined temperature is supplied to the heat transfer tube 12 provided inside the high-temperature absorber 11, and cooling is performed so that the temperature of the absorbing solution sprayed from above does not become too high. Therefore, the absorption of the refrigerant vapor entering from the high-temperature evaporator 7 into the absorbing liquid is not hindered. Then, the absorbing liquid is cooled by the heat transfer tube 12 of the high-temperature absorber 11, and hot water whose temperature has been increased to about 130 ° C. is supplied to the tower bottom heating or the like.

On the other hand, the refrigerant liquid that has entered the low-temperature evaporator 5 is sprayed by the refrigerant pump P2 onto the heat transfer tube 6 provided therein, and removes the heat of the fluid to be cooled flowing inside the heat transfer tube 6. Evaporates, for example, the fluid to be cooled at 35 ° C. is cooled to 20 ° C.

The refrigerant vapor evaporated by the low-temperature evaporator 5 enters the low-temperature absorber 9 and is absorbed by the absorption liquid (intermediate liquid) supplied from the high-temperature absorber 11 and scattered from above, and the concentration of the absorption liquid further decreases. That is, the absorption liquid pump P
4 returns to the regenerator 1.

The absorption liquid (intermediate liquid) supplied from the high-temperature absorber 1 and entering the low-temperature absorber 9 and the absorption liquid (dilute liquid) returned from the low-temperature absorber 9 to the regenerator 1 are separated by a low-temperature heat exchanger. 1
3, the temperature of the absorbing solution (intermediate solution) entering the low-temperature absorber 9 decreases and the temperature of the absorbing solution (dilute solution) entering the regenerator 1 increases. The amount of cooling required in the low-temperature absorber 9 to promote the evaporation of the refrigerant in the low-temperature evaporator 5 is reduced.

The heat transfer tube 10 is provided inside the low-temperature absorber 9.
In this case, cooling water is supplied, and the absorbing liquid (intermediate liquid) sprayed from above is cooled.
The refrigerant vapor coming from is well absorbed by the absorbing liquid.

In the absorption refrigerator in which the refrigerant and the absorption liquid circulate as described above, the control means 25 has at least the following functions.

For example, the bottom of the tower is heated with hot water that has been passed through the heat transfer tube 12 of the high-temperature absorber 11 and heated, and the fluid to be cooled supplied at, for example, 35 ° C. is passed through the heat transfer tube 6 for 20 minutes. The operation of the absorption type refrigerator having the above-described configuration by opening the valves 15, 16, and 18 and closing the valve 17 so as to cool the cooling unit to a temperature of 0 ° C. will be described. 20 so that the temperature of the hot water detected by
The opening of the flow control valve 21 is controlled.

That is, the flow control valve 21 narrows the opening (opening) when the temperature of the hot water detected by the temperature sensor 20 is higher (lower) than the set value, for example, based on a predetermined opening degree set in advance. The amount of cooling water supplied to the heat transfer tubes 4 of the condenser 3 is reduced (increased), the amount of heat taken from the overhead vapor in the regenerator 1 is reduced (increased), and the heat is heated from the high-temperature absorber 11. The temperature of the supplied hot water is lowered (increased) and is controlled by the control means 25 so as to reach a set value.

The control means 25 controls the opening of the flow control valve 22 so that the temperature of the fluid to be cooled detected by the temperature sensor 19 becomes a set value.

The flow rate control valve 22 opens (opens) when the temperature of the fluid to be cooled detected by the temperature sensor 19 is higher (lower) than a set value, for example, based on a predetermined opening degree set in advance. T) increasing (decreasing) the amount of cooling water flowing through the heat transfer tube 10 of the low-temperature absorber 9, and increasing (decreasing) the amount of heat radiation of the absorbing liquid and the refrigerant in the low-temperature absorber 9.
Is controlled by the control means 25 so as to accelerate (suppress) the evaporation of the refrigerant in the cooling medium and to lower (increase) the temperature of the fluid to be cooled and supplied from the low-temperature evaporator 5 so as to reach a set value.

The control means 25 operates the valve 1 so that the temperature of the fluid to be cooled detected by the temperature sensor 19 becomes a set value.
5 is controlled.

That is, based on, for example, a predetermined opening degree set in advance, when the temperature of the fluid to be cooled detected by the temperature sensor 19 is higher (lower) than a set value, the valve 15 opens the opening degree (throttles). T) increasing (decreasing) the flow rate of the absorbing liquid (intermediate liquid) supplied to the low-temperature absorber 9 and increasing (decreasing) the refrigerant absorption amount in the low-temperature absorber 9 to promote the evaporation of the refrigerant in the low-temperature evaporator 5. The temperature of the fluid to be cooled and supplied from the low-temperature evaporator 5 is suppressed (suppressed) by the control means 25 so as to lower (increase) the temperature to a set value.

The control means 25 controls the liquid level of the refrigerant liquid detected by the liquid level sensor 23 so as to be at a predetermined position.
The opening of the valve 18 is controlled.

That is, the valve 18 throttles the opening when the liquid level of the refrigerant liquid detected by the liquid level sensor 23 is higher than a predetermined position, based on a predetermined opening degree set in advance. When the liquid level of the refrigerant liquid detected by the controller is lower than a predetermined position, control is performed to increase the opening degree, or simply by opening and closing, so that the liquid level of the refrigerant liquid in the low-temperature evaporator 5 is controlled within a predetermined range. Is done.

Further, the control means 25 operates such that the liquid level of the absorbing liquid detected by the liquid level sensor 24 is at a predetermined position.
The operation of the absorbent pump P4 is controlled.

That is, the control means 25 controls the low-temperature absorber 9
By controlling the number of revolutions of the absorbent pump P4 so that the liquid level of the absorbent in the inside is within a predetermined range, or simply turning on / off the absorbent pump P4, the liquid level of the absorbent in the low-temperature absorber 9 is controlled. Control the position.

Instead of controlling the opening of the valve 15 based on the temperature of the fluid to be cooled detected by the temperature sensor 19,
The control unit 25 may be configured to perform control based on the temperature of the refrigerant in the low-temperature evaporator 5.

Also, instead of controlling the liquid level of the absorbing liquid in the low-temperature absorber 9 by the control by the absorbing liquid pump P4, the opening degree of the valve 16 is adjusted to adjust the opening of the low-temperature absorber 9. The control unit 25 may be configured to control the level of the absorbing liquid.

Further, instead of controlling the opening of the flow control valve 21 so that the temperature of the hot water detected by the temperature sensor 20 becomes a set value, the temperature of the hot water supplied by heating from the high temperature absorber 11 or the high temperature The control means 25 may be configured to control the opening of the flow control valve 21 so that the pressure or the temperature of the refrigerant vapor generated in the evaporator 7 becomes a predetermined value.

When the valves 15, 16, 17, and 18 are closed, the refrigerant and the absorbent can be circulated only by the regenerator 1, the condenser 3, the high-temperature evaporator 7, and the high-temperature absorber 11 only. It can also be used as a device having only a heating function.

When the absorbent pump P4 is operated with the valve 17 opened and the valves 15 and 16 closed, the absorbent circulates between the low-temperature absorber 9 and the low-temperature heat exchanger 13.
The low-temperature absorber 9 can perform a dilution operation of the absorbing liquid in which the absorbing liquid absorbs the refrigerant.

Further, as shown in FIG.
2 and a valve 26 is provided in the pipe so that the refrigerant liquid can be pumped from the low-temperature evaporator 5 to the high-temperature evaporator 7 so that the refrigerant liquid level in the low-temperature evaporator 5 becomes higher than a predetermined position. Alternatively, the valve 26 may be opened by a command from the control means 25, and a part of the refrigerant liquid sent by the refrigerant pump P2 may be pumped to the high-temperature evaporator 7.

Also, the amount of the refrigerant liquid pumped from the low-temperature evaporator 5 to the high-temperature evaporator 7 can be controlled by the rotation speed of the refrigerant pump P2.

Further, the supply of the refrigerant liquid from the condenser 3 to the low-temperature evaporator 5 can be configured so as to flow by the pressure difference and the own weight as shown in FIG.

Further, the refrigerant vapor supplied from the condenser 3 to the high-temperature evaporator 7 is supplied to either the regenerator 1 or the high-temperature evaporator 7,
Alternatively, a heat exchanger for exchanging heat with the drain of the overhead vapor which has been supplied to both and has performed the heating function is installed, and the condenser 3 is provided.
It is also possible to configure so that the refrigerant liquid from the tank is preheated and supplied to the high-temperature evaporator 7, so that the efficiency of heat recovery is further improved.

[0051]

As described above, according to the absorption refrigerator of the present invention, not only the heating action such as the heating at the bottom of the tower using the vapor at the top of the chemical plant as a heat source, but also the product obtained in the chemical plant or the like can be obtained. Since the cooling of products and intermediate products can be performed by a single device, a large installation space as in the related art is not required, and the piping thereof is not complicated.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing one embodiment.

FIG. 2 is an explanatory diagram showing another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Regenerator 2 Heat transfer tube 3 Condenser 4 Heat transfer tube 5 Low temperature evaporator 6 Heat transfer tube 7 High temperature evaporator 8 Heat transfer tube 9 Low temperature absorber 10 Heat transfer tube 11 High temperature absorber 12 Heat transfer tube 13 Low temperature heat exchanger 14 High temperature heat exchanger 15, 16, 17, 18 Valve 19, 20 Temperature sensor 21, 22 Flow control valve 23, 24 Liquid level sensor 25 Control means P1, P2, P3 Refrigerant pump P4, P5 Absorbing liquid pump

Claims (11)

[Claims] 1. A high-temperature evaporator to which a heat source fluid is supplied to evaporate a refrigerant, a high-temperature absorber to absorb refrigerant vapor supplied from the high-temperature evaporator into an absorbent, and a refrigerant to be cooled by the heat of evaporation of the refrigerant. A low-temperature evaporator for cooling, a low-temperature absorber for absorbing the refrigerant vapor supplied from the low-temperature evaporator into an absorbing liquid, and an evaporating and separating the refrigerant by heating the absorbing liquid to remove the absorbing liquid having a low concentration of the refrigerant. A regenerator that circulates and supplies a high-temperature absorber and a low-temperature absorber in this order, and a condenser that cools and condenses the refrigerant vapor supplied from the regenerator and supplies the refrigerant vapor to the high-temperature and low-temperature evaporators. Absorption refrigerator. 2. A low-temperature heat exchanger for exchanging heat between an absorption liquid supplied from a high-temperature absorber to a low-temperature absorber and an absorption liquid returned from the low-temperature absorber to a regenerator, and an absorption supplied from the high-temperature absorber. 2. The absorption refrigerator according to claim 1, further comprising a high-temperature heat exchanger for exchanging heat between the liquid and the absorption liquid supplied from the regenerator to the high-temperature absorber. 3. A pipe line is formed so that the absorbing liquid having absorbed the refrigerant vapor in the high-temperature absorber can flow into the regenerator, a pipe line for returning the absorbing liquid from the low-temperature absorber to the regenerator, and a low-temperature pipe line from the condenser. 3. The absorption refrigerator according to claim 1, wherein a valve is provided in a pipe for flowing the refrigerant liquid to the evaporator. 4. A valve for returning the absorbent from the low-temperature absorber to the regenerator (hereinafter, referred to as a first valve) is provided downstream of the low-temperature heat exchanger, and a refrigerant vapor is supplied to the high-temperature absorber. A valve (hereinafter, referred to as a second valve) provided downstream of the high-temperature heat exchanger in a pipeline for supplying the absorbent absorbing the water to the low-temperature regenerator, and between the low-temperature heat exchanger and the first valve 4. The absorption refrigerator according to claim 3, wherein the pipeline of (1) and the pipeline between the high-temperature heat exchanger and the second valve are connected by a pipeline provided with a valve. 5. A control device for controlling a flow rate of an absorbing liquid supplied to a low-temperature absorber based on a low-temperature evaporator outlet side temperature of a fluid to be cooled or a temperature of a refrigerant in the low-temperature evaporator. The absorption refrigerator according to any one of claims 1 to 4, wherein: 6. A control means for controlling the flow rate of the refrigerant liquid supplied from the condenser to the low-temperature evaporator based on the level of the refrigerant liquid in the low-temperature evaporator.
6. The absorption refrigerator according to any one of claims 1 to 5. 7. A control means for controlling the flow rate of the absorbing liquid supplied from the low-temperature absorber to the regenerator based on the level of the absorbing liquid in the low-temperature absorber.
7. The absorption refrigerator according to any one of claims 6 to 6. 8. A cooling fluid flowing pipe is provided in parallel with the low temperature absorber and the condenser, and a flow rate of the cooling fluid supplied to the low temperature absorber is controlled based on a temperature of the fluid to be cooled, and Control means is provided for controlling the flow rate of the cooling fluid supplied to the condenser based on the pressure or temperature of the refrigerant vapor generated in the high-temperature evaporator or the inlet or outlet temperature of the fluid supplied to the high-temperature absorber. The absorption refrigerator according to any one of claims 1 to 7, wherein: 9. A pipe line is provided for supplying a refrigerant liquid from a low-temperature evaporator to a high-temperature evaporator.
8. The absorption refrigerator according to any one of 8. 10. A control means for controlling the supply of the refrigerant liquid from the low-temperature evaporator to the high-temperature evaporator based on the amount of the refrigerant liquid in the low-temperature evaporator.
2. The absorption refrigerator according to 1. 11. A heat exchanger for exchanging heat between a heat source fluid that has been heated by at least one of a regenerator and a high-temperature evaporator and a refrigerant liquid supplied from the condenser to the high-temperature evaporator is provided. The absorption refrigerator according to any one of claims 1 to 10, wherein