JPH04244559A - Multi-stage multi-element freezer - Google Patents

Abstract

PURPOSE:To provide a multi-stage multi-element freezer capable of performing an efficient setting of a lower temperature. CONSTITUTION:A vapor outlet side of a gas-liquid separator 18 of a low temperature freezing cycle 12 is connected to a refrigerant separator 101 having a functional film having an easy selectiveness in respect to a transition of specified component of refrigerant and at the same time an outlet of the refrigerant separator 101 is connected to an evaporator 22 communicating with the second compressor 17 of a low temperature side freezing cycle 12 through the second heat exchanger 20 and the third throttle device 21 and then the transit refrigerant outlet of the refrigerant separator 101 is connected to a low pressure side of the second throttle device 19. It is possible to get a low temperature more efficiently by increasing a concentration of the characteristic component in the refrigerant with the refrigerant separator 101.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multistage refrigeration system using a mixed refrigerant to obtain a lower temperature.

0002

BACKGROUND OF THE INVENTION Conventionally, as a system for obtaining a low temperature using a refrigeration system, a multi-stage multi-component refrigeration cycle described in Japanese Patent Application Laid-Open No. 62-26458 has been used, and FIG. 4 shows an example of a conventional refrigeration system. It is a refrigeration cycle diagram.

In FIG. 4, the refrigeration system has a high temperature side refrigeration cycle 1 and a low temperature side refrigeration cycle 2, and the high temperature side refrigeration cycle 1 has a first compressor 3, a condenser 4, and a first expansion device 5.
The low temperature side refrigeration cycle 2 is connected to the high temperature side refrigeration cycle 1 via the heat exchanger 6.
It consists of a compressor 7, a second throttle device 8, and an evaporator 9.

In the refrigeration system configured as described above, refrigerant vapor compressed by the first compressor 3 of the high temperature side refrigeration cycle 1 is condensed by the condenser 4 to generate high temperature, and the first throttle It is expanded by the device 5, evaporated in the heat exchanger 6, and sucked into the first compressor 3 again. In the heat exchanger 6, the evaporated refrigerant of the high temperature side refrigeration cycle and the refrigerant vapor compressed by the second compressor 7 of the low temperature side refrigeration cycle are heat exchanged, and the refrigerant vapor of the low temperature side refrigeration cycle 2 is condensed. This condensed liquid is expanded by the second throttle device 8 and evaporated in the evaporator 9 to generate a low temperature. In this way, lower temperatures can be obtained without increasing the compression ratio of the refrigerant.

[0005]

[Problems to be Solved by the Invention] However, in the conventional configuration described above, the following problems were encountered in order to obtain a lower temperature.

1. It is necessary to lower the evaporation temperature of the low-temperature side refrigeration cycle, but lowering the evaporation temperature increases the compression ratio and reduces operational efficiency. 2. Furthermore, it is possible to obtain a low temperature by connecting independent refrigeration cycles to create a multi-component cycle, but the equipment becomes complicated.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a multi-stage, multi-component refrigeration system that can efficiently obtain lower temperatures.

[0008]

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a high temperature side refrigeration cycle in which a first compressor, a condenser, a first expansion device, and a first heat exchanger are connected in an annular manner. A non-azeotropic mixed refrigerant is used as the refrigerant, and the refrigeration cycle is connected to the high temperature side refrigeration cycle via a first heat exchanger, and the first heat exchanger, the second compressor, the gas-liquid separator, and the gas-liquid separator are connected to the high-temperature side refrigeration cycle. It has two independent refrigeration cycles, a second throttling device communicating with the liquid side outlet of the separator, and a low temperature side refrigeration cycle in which a second heat exchanger is connected in an annular manner. The vapor side outlet of the separator is connected to a refrigerant separator that easily permeates specific components in the refrigerant, and the outlet of the refrigerant separator is connected to an evaporator that communicates with a second compressor of the low temperature side refrigeration cycle. The second heat exchanger and the third expansion device are connected to each other, and the permeated refrigerant outlet of the refrigerant separation device is connected to the low pressure side of the second expansion device.

[0009] Furthermore, the refrigerant separator has a structure in which a plurality of refrigerant separators are connected in series to allow specific components in the refrigerant to pass through easily.

0010

[Operation] With the above configuration, in the high-temperature side refrigeration cycle, the refrigerant vapor compressed by the first compressor is condensed by the condenser to generate high temperature, and is expanded by the first expansion device to generate the first It is evaporated in the heat exchanger and sucked into the first compressor again.

In the first heat exchanger, the evaporative refrigerant of the high temperature side refrigeration cycle and the second evaporative refrigerant of the low temperature side refrigeration cycle are
The refrigerant vapor compressed by the compressor exchanges heat with the refrigerant vapor in the low temperature side refrigeration cycle, and the refrigerant vapor in the low temperature side refrigeration cycle is partially condensed. This partially cooled and liquefied refrigerant enters a gas-liquid separator and is separated into vapor with a high concentration of low boiling point components and liquid with a high concentration of high boiling point components.

[0012] Then, the vapor with a high concentration of low-boiling point components flows into the refrigerant separation device, and among this vapor, the high-boiling point refrigerant that easily permeates through the functional membrane passes through the permeated refrigerant outlet to the low pressure of the second throttling device. returned to the side. On the other hand, since it is difficult for the refrigerant with low boiling point components to permeate through the functional membrane, the concentration of the low boiling point components becomes even higher at the outlet of the refrigerant separation device and enters the second heat exchanger.

Furthermore, in the second heat exchanger, the high temperature, high pressure refrigerant vapor with a high concentration of low boiling point components is cooled and liquefied by heat exchange with the low temperature, low pressure refrigerant with a high concentration of high boiling point components,
It is expanded by the third throttling device and evaporated in the evaporator. At this time, since the concentration of the low boiling point component is high, a lower temperature can be obtained.

Furthermore, when a plurality of refrigerant separators are connected in series, vapor with a high concentration of low-boiling point components flows into the first refrigerant separator, while high-boiling components that easily permeate through the functional membrane are permeated. It passes through the outlet pipe and returns to the low pressure side of the second throttling device. On the other hand, low boiling point components have difficulty permeating the functional membrane, so
At the outlet of the first refrigerant separator, the concentration of low-boiling components is further increased and enters the second refrigerant separator.

Furthermore, in the second refrigerant separation device, similarly,
High boiling point components that easily permeate the functional membrane are returned to the low pressure side of the second throttling device through the permeated refrigerant outlet, while low boiling point components that are difficult to permeate through the functional membrane are returned to the low pressure side of the second throttling device through the permeated refrigerant outlet. It becomes even more concentrated and enters the second heat exchanger.

In the second heat exchanger, the high-temperature, high-pressure refrigerant vapor with a high concentration of low-boiling components is cooled and liquefied by exchanging heat with the low-temperature, low-pressure refrigerant with a high concentration of high-boiling components. It is expanded by the device and evaporated in the evaporator. At this time, the concentration of low boiling point components is high, and a lower temperature can be obtained.

[0017]

[Example] First, the experimental results that revealed that it is possible to use a functional membrane for refrigerant separation will be explained.

In FIG. 1, a refrigerant separation device (hereinafter simply referred to as a separator) 101 using a functional membrane has a separator main body 1.
02 is partitioned into a high-pressure side space a and a low-pressure side space b by a net-like holder 104, and a functional membrane 103 is installed on the high-pressure side of the holder 104. In addition, a high pressure refrigerant inlet pipe 105 is provided in the high pressure side space a of the separator main body 102.
and an outlet pipe 106 are open, and a permeated refrigerant outlet pipe 107 is open to the low pressure side space b.

In the separator 101 configured as described above, a benzene solution of dimethyl silicone is spread on water to form an ultra-thin film, and then a porous film of polypropylene (
R-22 and R
A case will be described in which a mixed refrigerant of -13B1 is separated.

The mixed refrigerant pressurized by a compressor or the like is passed through the inlet pipe 105 to the high pressure side space a of the separator main body 102.
sent to. Here, due to the pressure difference between the high-pressure side space a and the low-pressure side space b, a part of the refrigerant permeates into the low-pressure side space b and is discharged from the permeated refrigerant outlet pipe 107. At this time R-22
Since R-13B1 permeates more easily than R-13B1, the refrigerant discharged from the permeated refrigerant outlet pipe 107 has a higher proportion of R-22 than the refrigerant composition of the inlet pipe 105. On the other hand, the refrigerant composition discharged from the high-pressure refrigerant outlet pipe 106 without passing through the functional membrane 103 has a lower R-22 ratio.

[0021] Here, an example of the experimental results is shown in Table 1. Table 1
Although the case in which refrigerant vapor was introduced from the inlet pipe of the separator 101 was shown in , separation is possible even if refrigerant liquid or a mixture of vapor and liquid is introduced.

[0022] Thus, it has become clear that refrigerant separation can be performed using a functional membrane.

[0023]

In the previous experiment, a polymer composite film was prepared by spreading a benzene solution of dimethyl silicone on water to form an ultra-thin film, and then transferring the film to a porous polypropylene film (Celanese: Duraguard). I used it, but
Natural rubber, polyethylene, polyvinyl acetate, etc. may be used as the non-porous polymer membrane material other than dimethyl silicone.

Furthermore, even if a porous polymer membrane, a biological membrane, or the like is used to separate the refrigerant by utilizing the ratio of permeation amounts, the gist of the present invention will not be exceeded. Next, as an example of a refrigeration cycle using the above-mentioned functional membrane, a non-azeotropic mixed refrigerant of R-22 and R-13B1 is used as the refrigerant in the low-temperature side refrigeration cycle, and R-13B1, which is difficult to permeate through the functional membrane, is used as a refrigerant. Figure 2 shows Example 1 in which a low temperature is obtained by increasing the component ratio of
The explanation will be based on.

In FIG. 2, the refrigeration system has a high temperature side refrigeration cycle 11 and a low temperature side refrigeration cycle 12, and the high temperature side refrigeration cycle 11 has a first compressor 13, a condenser 14, and a first
It is composed of a throttle device 15 and a first heat exchanger 16. In addition, a first heat exchanger 1 is provided in the high temperature side refrigeration cycle 11.
The low temperature side refrigeration cycle 12 connected via the second
It has a compressor 17, a gas-liquid separator 18, a second throttle device 19, and a second heat exchanger 20, and the liquid side outlet of the gas-liquid separator 18 is connected to the second throttle device 19 and the second heat exchanger 19. It is connected in an annular manner to the suction side of the second compressor 17 via the exchanger 20, and the vapor side outlet of the gas-liquid separator 18 is connected to the inlet pipe 105 of the separator 101 configured as described above. The outlet pipe 106 of the vessel 101 is connected to the evaporator 22 via the second heat exchanger 20 and the third throttling device 21, and the permeated refrigerant outlet pipe 107 is connected to the low pressure side after the second throttling device 19. ing.

The operation of the refrigeration cycle constructed as above will be explained. First, in the high temperature side refrigeration cycle 11, refrigerant vapor compressed by the first compressor 13 is condensed by the condenser 14 to generate high temperature, and expanded by the first expansion device 15 to perform the first heat exchange. It evaporates in the container 16 and is sucked into the first compressor 13 again.

[0028] In the first heat exchanger 16,
The evaporated refrigerant of the high temperature side refrigeration cycle 11 and the refrigerant vapor compressed by the second compressor 17 of the low temperature side refrigeration cycle 12 are exchanged to partially condense the refrigerant vapor of the low temperature side refrigeration cycle 12. This partially cooled and liquefied refrigerant enters the gas-liquid separator 18 and is separated into vapor with a high concentration of R-13B1, a low boiling point component, and liquid with a high concentration of R-22, a high boiling point component. .

Then, the vapor with a high concentration of low boiling point component R-13B1 flows into the separator 101, and among this vapor, the high boiling point component R-22 that easily permeates the functional membrane 103 passes through the permeation outlet pipe 107. It is returned between the outlet of the second throttling device 19 and the inlet of the second heat exchanger 20. On the other hand, the low boiling point component R-13B1 is difficult to permeate through the functional membrane 103.
In the outlet piping 106 of the separator 101, R-13
The concentration of B1 increases and enters the second heat exchanger 20.

Furthermore, in the second heat exchanger 20, the high-temperature, high-pressure refrigerant vapor with a high concentration of the low-boiling point component R-13B1 is cooled by heat exchange with the low-temperature, low-pressure refrigerant with a high concentration of the high-boiling point component R-22. It is liquefied, expanded by the third throttle device 21 and evaporated in the evaporator 22. At this time, since the concentration of the low boiling point component R-13B1 is high, a lower temperature can be obtained.

Next, FIG. 3 shows a second embodiment in which a plurality of refrigerant separators having functional membranes are connected to obtain an even lower temperature.
The explanation will be based on. Incidentally, members that perform the same functions as those in the first embodiment are given the same numbers and their explanations will be omitted.

In FIG. 3, the outlet pipe 106 of the first separator 101 is connected to the inlet side of the second separator 201, and the outlet pipe 206 of the second separator 201 is connected to the second separator 201.
It is connected to an evaporator 22 via a heat exchanger 20 and a third throttle device 21 . In addition, the first and second separators 10
1 , 201 permeated refrigerant outlet piping 107 , 207
is connected to the low pressure side of the second throttle device 19.

The operation of the refrigeration cycle constructed as above will be explained. First, in the high temperature side refrigeration cycle 11, refrigerant vapor compressed by the first compressor 13 is condensed by the condenser 14 to generate high temperature, and the first throttle device 1
5 and evaporated in the first heat exchanger 16, and then sucked into the first compressor 13 again.

In the first heat exchanger 16, the evaporative refrigerant of the high temperature side refrigeration cycle 11 and the low temperature side refrigeration cycle 12
The refrigerant vapor compressed by the second compressor 17 is exchanged with the refrigerant vapor, and the refrigerant vapor in the low-temperature side refrigeration cycle 12 is partially condensed. This partially cooled and liquefied refrigerant enters the gas-liquid separator 18 and is separated into vapor with a high concentration of low boiling point component R-13B1 and liquid with high concentration of high boiling point component R-22.

[0035]Then, the vapor with a high concentration of the low boiling point component R-13B1 flows into the first separator 101 and passes through the functional membrane 10.
R-22 that easily permeates through the permeation outlet pipe 107 is returned between the outlet of the second throttle device 19 and the inlet of the second heat exchanger 20. On the other hand, R-13B1 has a functional film 103
Because R-13B1 is difficult to pass through, the concentration of R-13B1 becomes even higher in the outlet pipe 106 of the first separator 101 and enters the second separator 201.

Furthermore, in the second separator 201, similarly, R-22, which easily permeates the functional membrane 203, passes through the permeate outlet pipe 207 and reaches the permeate outlet pipe 107 of the first separator 101, and R-13B1 Because it is difficult to permeate through the functional membrane 203, the outlet piping 2 of the second separator 201
In 06, the concentration of R-13B1 was further increased and the second
into the heat exchanger 20.

In the second heat exchanger 20, the high temperature, high pressure refrigerant vapor with a high concentration of the low boiling point component R-13B1 is cooled by heat exchange with the low temperature, low pressure refrigerant with a high concentration of the high boiling point component R-22. It is liquefied, expanded by the third throttle device 21 and evaporated in the evaporator 22. At this time, low boiling point component R-1
The concentration of 3B1 is higher and lower temperatures can be obtained.

As described above, according to this embodiment, a lower temperature can be obtained by connecting two refrigerant separators having functional membranes. Although the second embodiment shows a case in which two refrigerant separators having functional membranes are connected, a lower temperature can be obtained by connecting more separators in the same way.

[0039]

As described above, according to the present invention, a refrigerant separator having a functional membrane that facilitates the passage of a specific type of refrigerant is provided at the vapor side outlet of the gas-liquid separator of the low temperature side refrigeration cycle. This has the effect that lower temperatures can be efficiently obtained.

Furthermore, by providing a plurality of refrigerant separation devices each having a functional membrane, the performance of the separation circuit can be further improved and a lower temperature can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a detailed sectional view of a refrigerant separator in one embodiment of the present invention.

FIG. 2 is a refrigeration cycle diagram showing Example 1 in which the same separator is used.

FIG. 3 is a refrigeration cycle diagram showing a second embodiment in which two separators are used.

FIG. 4 is a diagram of a refrigeration cycle in a conventional example.

[Explanation of symbols]

11 High temperature side refrigeration cycle 12 Low temperature side refrigeration cycle 13 First compressor 14 Condenser 15 First aperture device 16 First heat exchanger 17 Second compressor 18 Gas-liquid separator 19 Second diaphragm device 20 Second heat exchanger 21 Third diaphragm device 22 Evaporator 101 First refrigerant separation device 103 Functional membrane 201 Second refrigerant separation device

Claims (2)

[Claims] 1. A high-temperature side refrigeration cycle in which a first compressor, a condenser, a first expansion device, and a first heat exchanger are connected in a ring, a non-azeotropic mixed refrigerant is used as a refrigerant, and the high-temperature side a second throttling device connected to the refrigeration cycle via the first heat exchanger and communicating with the first heat exchanger, the second compressor, the gas-liquid separator, and the liquid side outlet of the gas-liquid separator; It has two independent refrigeration cycles, including a low-temperature side refrigeration cycle connected in a ring with a second heat exchanger, and the vapor side outlet of the gas-liquid separator of the low-temperature side refrigeration cycle is connected to the vapor side outlet of the gas-liquid separator to facilitate the removal of specific components in the refrigerant. The outlet of the refrigerant separator is connected to an evaporator communicating with a second compressor of the low-temperature side refrigeration cycle via a second heat exchanger and a third throttling device. , a multi-stage multi-component refrigeration system in which a permeated refrigerant outlet of the refrigerant separation device is connected to a low pressure side of a second expansion device. 2. The multi-stage multi-component refrigeration system according to claim 1, further comprising a plurality of refrigerant separators connected in series that allow specific components in the refrigerant to pass through easily.