JP3327705B2 - Refrigerant composition and refrigeration apparatus using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a refrigerant composition and a refrigeration system using the same.

[0002]

2. Description of the Related Art A conventional refrigeration system using a non-azeotropic mixed refrigerant is constructed by condensing a refrigerant having the highest boiling point contained in the non-azeotropic mixed refrigerant in order from a refrigerant having a lower boiling point in a single condenser. After the pressure is reduced, the refrigerant having the highest boiling point is evaporated from the refrigerant having the lowest boiling point in a single evaporator.

[0003] The non-azeotropic mixed refrigerant is used to obtain the extremely low temperature of about -150 ° C. The refrigerant R141b i.e. 1,1-dichloro-1-fluoroethane _{(CC1 2 F-CH 3)} , refrigerant R152a i.e. 1.1-difluoroethane (CHF _2- CH ₃ ), refrigerant R23 or trifluoroethane (CHF ₃ ), and refrigerant R142 or tetrafluoromethane (C
F ₄ ) and refrigerant R50, that is, methane (CH ₄ ).

[0004]

However, the refrigerant R141b contained in the non-azeotropic refrigerant mixture is subject to the first regulation of international regulation measures for preventing ozone layer destruction. CFCs (R1
1, R12, R113, R114, R115, etc.), that is, so-called alternative chlorofluorocarbon HCFC (R22, R141b, R142b, R123)
Etc.).

[0005] However, since alternative CFC HCFCs still have the possibility of depleting the ozone layer, their reduction schedule has been determined as the subject of the second regulation. Therefore, development of a refrigerant composition having no possibility of destruction of the ozone layer and an ultra-low-temperature refrigeration apparatus using the refrigerant composition has been an issue.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the gist of the first invention is to provide octafluorocyclobutane, difluoromethane, trifluoromethane and tetrafluoromethane. A refrigerant composition comprising methane and methane.

[0007] The composition of the refrigerant composition is 30 to 80% by weight of octafluorocyclobutane, 1 to 20% by weight of difluoromethane, 5 to 30% by weight of trifluoromethane, 5 to 40% by weight of tetrafluoromethane and 5 to 40% by weight of methane. It can be 0.5 to 20% by weight.

[0008] Argon can be added. In this case, the composition of the refrigerant composition is 30 to 80% by weight of octafluorocyclobutane, 1 to 20% by weight of difluoromethane, 5 to 30% by weight of trifluoromethane, 5 to 40% by weight of tetrafluoromethane, and 0.5 to 40% by weight of methane. 20% by weight,
Argon can be 0.5 to 15% by weight.

The gist of the second invention is that a mixed refrigerant comprising the refrigerant composition according to claim 1, 2, 3 or 4 is filled therein, and a compressor for compressing the mixed refrigerant, A condenser that cools the high-temperature and high-pressure mixed refrigerant compressed by the compressor, a gas-liquid separator that mainly separates the cooled mixed refrigerant into a high-boiling liquid refrigerant and a residual gas refrigerant, and is separated by the gas-liquid separator. And a middle heat exchanger for cooling the liquid refrigerant depressurized by the throttle by exchanging heat between the return gas refrigerant and the residual gas refrigerant separated by the gas-liquid separator. A plurality of cooling units for sequentially separating and cooling the low-boiling refrigerant from the high-boiling refrigerant, and a cooler for evaporating the low-boiling liquid refrigerant cooled by the final-stage cooling unit after reducing the pressure. Refrigeration equipment.

[0010]

Since the refrigerant composition of the present invention does not contain chlorine, there is no possibility of destroying the ozone layer.

According to the composition of the second aspect, an ultra-low temperature of -150 ° C. or less can be obtained by a refrigerating apparatus using the refrigerant composition.

If argon is added to the refrigerant composition,
It can improve the flowability of methane in the cryogenic cooler.

In the refrigeration system of the present invention, the high-temperature and high-pressure mixed refrigerant compressed by the compressor is cooled by the condenser,
In the process of flowing through the plurality of stages of cooling means, low-boiling refrigerants are sequentially separated from high-boiling refrigerants and cooled. The low-boiling liquid refrigerant cooled by the cooling means at the last stage is decompressed and then evaporated by the cooler.

[0014]

FIG. 1 shows a refrigerant system diagram of a refrigeration apparatus according to one embodiment of the present invention. The discharge side of the compressor 1 is connected to the inlet of the condenser 3 via the oil separator 2. The outlet of the condenser 3 is connected to the inlet of the first gas-liquid separator 5 via the auxiliary condenser 4. The gas phase 5a of the first gas-liquid separator 5 is connected to the outer tube inlet of the first intermediate heat exchanger 6, and the liquid phase 5b is connected to the first intermediate heat exchanger 6 via the first throttle 7. Connected to the inner pipe inlet.

The first intermediate heat exchanger 6 is formed of a double pipe, and has an outer pipe inlet and an inner pipe outlet in order to increase the efficiency of heat exchange between the refrigerant flowing in the outer pipe and the refrigerant flowing in the inner pipe. Are provided at one end of the intermediate heat exchanger 6, and the outer pipe outlet and the inner pipe inlet are provided at the other end.

Thus, the first gas-liquid separator 5 and the first
The first stage cooling means 1S is formed by the intermediate heat exchanger 6 and the first throttle 7.
Is formed. Similarly, the second gas-liquid separator 8, the second intermediate heat exchanger 9, and the second restrictor 10 allow the second stage cooling means 2S
Is a third gas-liquid separator 11, a third intermediate heat exchanger 12, and a third throttle.
13 forms a third stage cooling means 3S, and a fourth gas-liquid separator 14, a fourth intermediate heat exchanger 15 and a fourth throttle 16 form a fourth stage cooling means 4S.

The outer pipe outlet of the fourth intermediate heat exchanger 15 is connected to the inlet of a cooler 19 provided in the ultra low temperature storage via an auxiliary cooler 17 and a throttle 18. The outlet of the cooler 19 is connected to the inner pipe inlet of the fourth intermediate heat exchanger 15 via the auxiliary cooler 17.

The outlet of the inner pipe of the fourth intermediate heat exchanger 15 is located at the inlet of the inner pipe of the third intermediate heat exchanger 12, and the outlet of the inner pipe of the third intermediate heat exchanger 12 is located at the inner pipe of the second intermediate heat exchanger 9. At the inlet, the inner tube outlet of the second intermediate heat exchanger 9 is at the inner tube inlet of the first intermediate heat exchanger 6, and the inner tube outlet of the first intermediate heat exchanger 6 is at the compressor 1 via the auxiliary condenser 4. Is connected to the suction side.

In the refrigerant circuit of this refrigeration system, a refrigerant composition comprising five types of refrigerants having different boiling points is mixed, that is, a refrigerant.
RC318 (octafluorocyclobutane), refrigerant R32 (difluoromethane), refrigerant R23 (trifluoromethane),
Refrigerant R14 (tetrafluoromethane) and refrigerant R50 (methane)
And a non-azeotropic mixed refrigerant consisting of

Each refrigerant has a boiling point of RC318 at atmospheric pressure.
-5.75 ° C, R32 at -51.69 ° C, R23 at -82.15 ° C, R14 at -1
27.9 ℃, R50 is -161.5 ℃. The composition of each refrigerant is, for example, 56% by weight of RC318, 5% by weight of R32, and 17% by weight of R23.
% By weight, R14 by 17% by weight and R50 by 5% by weight.

Next, the operation will be described. The high-temperature and high-pressure gaseous mixed refrigerant discharged from the compressor 1 enters the oil separator 2 where oil is separated and removed, and then flows into the auxiliary condenser 3 where it is cooled to about 30 ° C. by cooling water. After that, it flows into the condenser 4. Here, low-boiling refrigerant therein by being further cooled to, for example, about 15 ° C. by the return refrigerant, that is,
All of RC318 and a part of R32 are liquefied and the first gas-liquid separator 5
Flows into.

Here, the high-boiling refrigerants R50, R14, R23 are converted from the liquid refrigerant comprising all of the low-boiling refrigerant RC318 and a part of R32.
And the residual gaseous refrigerant consisting of uncondensed R32. All of the separated liquid refrigerant RC318 and a part of R32 are decompressed by the first throttle 7, and then flow into the inner tube of the first intermediate heat exchanger 6, where they join with the return gas refrigerant and evaporate.

On the other hand, part of the residual gaseous refrigerant R32 and R23
, R14 and R50 are cooled to, for example, about -15 ° C. by exchanging heat with the return refrigerant flowing through the inner pipe and the separated residual gaseous refrigerant during the flow through the outer pipe of the first intermediate heat exchanger 6. As a result, all of R32 and a part of R23 therein are liquefied.

Next, the refrigerant flows into the second gas-liquid separator 8, where it is separated into a liquid refrigerant and a residual gas refrigerant. After all the liquid R32 and a part of R23 are decompressed by the second throttle 10, they flow into the inner tube of the second intermediate heat exchanger 9, where they merge with the return refrigerant and evaporate.

On the other hand, a part of the residual gas refrigerant R23 and R14, R5
In the process of flowing through the outer tube of the second intermediate heat exchanger 9, all of R0 is cooled to, for example, about -40 ° C. by the refrigerant flowing through the inner tube, so that all of R23 and a part of R14 are liquefied. I do.

This refrigerant flows into the third gas-liquid separator 11, where it is separated into a liquid refrigerant and a gaseous refrigerant. Liquid R23
After a part of the pressure R and R14 are depressurized by the third throttle 13, they flow into the inner pipe of the third intermediate heat exchanger 12, where they merge with the refrigerant flowing through the outer pipe and evaporate.

On the other hand, part of the residual gas refrigerant R14 and all of R50 are cooled to, for example, about -17 ° C. by the refrigerant flowing through the inner tube in the process of flowing through the outer tube of the third intermediate heat exchanger 12. As a result, all of R14 and a part of R50 therein are liquefied,
It flows into the gas-liquid separator 14, where it is separated into a liquid refrigerant and a gaseous refrigerant.

Part of the liquid R14 and all of the R50 are subjected to the fourth drawing.
After the pressure is reduced in 16, it flows into the inner pipe of the fourth intermediate heat exchanger 15, where it joins with the return refrigerant and evaporates. On the other hand, part of the residual gas refrigerant R14 and most of R50 are stored in the fourth intermediate heat exchanger 15.
In the process of flowing through the outer tube, the whole of R14 and R5 are cooled by, for example, about −100 ° C. by the refrigerant flowing through the inner tube.
A considerable part of 0 liquefies and flows into the auxiliary cooler 17, where it is further cooled by the return refrigerant from the cooler 19 to, for example, about -115 ° C., and most of R50 is liquefied.

The liquefied R14 and R50 are supplied to the fifth throttle 18
The temperature is lowered by reducing the pressure to about 155 ° C., for example, and flows into the cooler 19 at about −155 ° C., where it is evaporated to cool the inside of the ultra-low temperature storage to −150 ° C.

The refrigerant evaporated in the cooler 19 is supplied to the auxiliary cooler 17,
Each intermediate heat exchanger 15, 12, 9, 6 and the condenser 4 are returned to the compressor 1 in this order. The lubricating oil mixed with the refrigerant discharged from the discharge pipe of the compressor 1 and flowing out is separated in the oil separator 2, merged with the refrigerant returned to the compressor 1, and returned to the compressor 1.

The composition of the non-azeotropic refrigerant mixture is such that RC318 is 30 to 80.
% By weight, R32 is 1 to 30% by weight, R23 is 5 to 40% by weight, R14 is 5 to 40% by weight, and R50 is 0.5 to 20% by weight. It was confirmed that a very low temperature could be obtained.

In addition, argon (R740) was added to the non-azeotropic refrigerant mixture, and the composition thereof was 30 to 80% by weight of RC318 and 1% of R32.
30 to 30% by weight, R23 is 5 to 40% by weight, R14 is 5 to 40%
% By weight, R50 in the range of 0.5 to 15% by weight, and R740 in the range of 0.5 to 15% by weight.
Ultra-low temperatures below ℃ were obtained.

Incidentally, argon (R740) has a low boiling point (−18).
5.65 ° C.), although it does not itself exhibit a refrigeration effect, it improves the fluidity of methane (R50) in the final stage cooler 19 as a carrier gas to promote its evaporation and improve the refrigeration capacity.

[0034]

According to the refrigerant composition of the present invention, there is no possibility of destroying the ozone layer. Further, according to the refrigerating apparatus of the present invention, an ultra-low temperature of -150 ° C or lower can be stably obtained in the cooler.

[Brief description of the drawings]

FIG. 1 is a refrigerant system diagram of a refrigeration apparatus according to an embodiment of the present invention.

[Description of Signs] 1 Compressor 3 Condenser 5, 8, 11, 14 Gas-liquid separator 6, 9, 12, 15 Intermediate heat exchanger 19 Cooler 1S, 2S, 3S, 4S Cooling means

──────────────────────────────────────────────────続 き Continuing on the front page (72) Takayoshi Hamada 1st Takamichi, Iwazuka-cho, Nakamura-ku, Nagoya-shi Nagoya Research Laboratory, Mitsui Heavy Industries Co., Ltd. Mitsuo Yoneda, Nagoya Laboratory, Nagoya-shi, Nakamura-ku, Nagoya-shi, Nagoya Laboratory (72) Reference: JP-A-4-96989 (JP, A) JP-A-5-118677 (JP, A) JP-A-1-247479 (JP, A) JP-A-6-220433 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 7/00 C09K 5/04 F25B 1/00

Claims (5)

(57) [Claims] 1. A refrigerant composition comprising octafluorocyclobutane, difluoromethane, trifluoromethane, tetrafluoromethane and methane. 2. The composition of the above refrigerant composition comprises 30 to 80% by weight of octafluorocyclobutane and 1% of difluoromethane.
-20% by weight, trifluoromethane 5-30% by weight,
5 to 40% by weight of tetrafluoromethane, 0.5% of methane
The refrigerant composition according to claim 1, wherein the content is from 20 to 20% by weight. 3. The refrigerant composition according to claim 1, wherein argon is added. 4. The composition of the refrigerant composition, wherein octafluorocyclobutane is 30 to 80% by weight and difluoromethane is 1% by weight.
-20% by weight, trifluoromethane 5-30% by weight,
5 to 40% by weight of tetrafluoromethane, 0.5% of methane
4. The refrigerant composition according to claim 3, wherein the content of argon is 0.5 to 15% by weight and the content of argon is 0.5 to 15% by weight. 5. A mixed refrigerant comprising the refrigerant composition according to claim 1, 2, 3 or 4, and a compressor for compressing the mixed refrigerant, and a high-temperature and high-pressure compressed by the compressor. A condenser that cools the mixed refrigerant, a gas-liquid separator that mainly separates the cooled mixed refrigerant into a high-boiling liquid refrigerant and a residual gas refrigerant, and a throttle that depressurizes the liquid refrigerant separated by the gas-liquid separator. An intermediate heat exchanger for cooling the liquid refrigerant depressurized by the throttle by exchanging heat between the return gas refrigerant and the residual gas refrigerant separated by the gas-liquid separator,
A plurality of stages of cooling means for separating and cooling the low-boiling refrigerant sequentially from the high-boiling refrigerant, and a cooler for evaporating the low-boiling liquid refrigerant cooled by the final-stage cooling means after reducing the pressure thereof. Refrigeration equipment.