Mixed refrigerant suitable for cryogenic temperature zone as well as preparation method and application of mixed refrigerant

Abstract

The invention provides a mixed refrigerant suitable for a cryogenic temperature zone and a preparation method and application of the mixed refrigerant. The mixed refrigerant comprises a first refrigerant, a second refrigerant, a third refrigerant, a fourth refrigerant and a fifth refrigerant. The first refrigerant is argon and / or nitrogen, the second refrigerant is methane and / or krypton, the third refrigerant is selected from at least one of 1, 1-difluoroethylene, ethane and ethylene, the fourth refrigerant is 2, 3, 3, 3-tetrafluoro-1-propylene, and the fifth refrigerant is monochlorotrifluoropropene and / or hexafluoro-2-butene; based on the total mole number of the mixed refrigerant, the mole percent M1 of the first refrigerant is 0%-10%, the mole percent M2 of the second refrigerant is 5%-20%, the mole percent M3 of the third refrigerant is 25%-50%, the mole percent M4 of the fourth refrigerant is 10%-30%, and the mole percent M5 of the fifth refrigerant is 10%-30%. The ODP value of the mixed refrigerant is 0, the GWP value is lower than 150, and the mixed refrigerant is environmentally friendly, safe and suitable for an automatic cascade refrigeration system with the refrigeration temperature range from-100 DEG C to-150 DEG C.

Description

Technical Field

[0001] The present application relates to the field of refrigeration technology, and in particular to a mixed refrigerant suitable for cryogenic temperature zones, a preparation method thereof, and an application thereof. Background Art

[0002] Refrigerant, also known as coolant, is the medium substance used to complete energy conversion in refrigeration equipment. In modern refrigeration equipment, if a compressor is used to cool to a cryogenic temperature range of -100℃ to -150℃, a cascade refrigeration method is usually required. The refrigerants used in existing automatic cascade cryogenic systems usually require a mixture of multiple refrigerants. To reach the cryogenic temperature range of -100℃ to -150℃, a four- or five-stage automatic cascade refrigeration system is generally used, and the mixed refrigerant used usually requires a mixture of five or more refrigerants. When selecting a refrigerant, not only is it required to be non-toxic, have a low ozone depletion potential (ODP value) and global warming potential (GWP value), but it is also necessary to use a non-flammable refrigerant as much as possible.

[0003] Before the 21st century, traditional refrigeration systems used chlorine-containing refrigerants. Due to their ozone-depleting effects, the European Union banned the use of hydrochlorofluorocarbons (HCFCs) in refrigeration systems starting January 1, 2001, replacing them with hydrofluorocarbons (HFCs). With increasing environmental protection requirements, refrigerants must have minimal ODP and GWP values ​​to minimize their impact on the ozone layer and global warming. Although these HFC refrigerants have an ODP of 0, their GWP values ​​are generally high, making them greenhouse gases and slated for phase-out. In traditional -100°C to -150°C cascade refrigeration systems, tetrafluoromethane (R14) and trifluoromethane (R23) are almost standard and essential refrigerants. However, given the extremely high GWPs of R14 (5700) and R23 (12200), finding suitable alternatives is imperative.

[0004] Therefore, in order to meet environmental protection requirements to the greatest extent, there is an urgent need for a safe and environmentally friendly mixed refrigerant with an ODP value of zero, a GWP value less than 150, a refrigeration temperature range of -100℃ to -150℃, and suitable for automatic cascade refrigeration systems. Summary of the Invention

[0005] The purpose of this application is to provide a mixed refrigerant suitable for cryogenic temperature ranges, its preparation method, and application, to obtain a safe and environmentally friendly mixed refrigerant with an ODP value of zero, a GWP value of less than 150, a refrigeration temperature range of -100°C to -150°C, and suitable for automatic cascade refrigeration systems. The specific technical solution is as follows:

[0006] A first aspect of the present application provides a mixed refrigerant suitable for use in a cryogenic temperature zone, wherein the mixed refrigerant comprises a first refrigerant, a second refrigerant, a third refrigerant, a fourth refrigerant, and a fifth refrigerant;

[0007] The first refrigerant is argon and / or nitrogen, the second refrigerant is methane and / or krypton, the third refrigerant is at least one selected from 1,1-difluoroethylene, ethane, and ethylene, the fourth refrigerant is 2,3,3,3-tetrafluoro-1-propene, and the fifth refrigerant is monochlorotrifluoropropene and / or hexafluoro-2-butene;

[0008] Based on the total molar number of the mixed refrigerant, the mole percentage of the first refrigerant is M1, the mole percentage of the second refrigerant is M2, the mole percentage of the third refrigerant is M3, the mole percentage of the fourth refrigerant is M4, and the mole percentage of the fifth refrigerant is M5, M1 is 0% to 10%; M2 is 5% to 20%; M3 is 25% to 50%; M4 is 10% to 30%; M5 is 10% to 30%.

[0009] In some embodiments, M1 is 0% to 5%; M2 is 5% to 10%; M3 is 25% to 30%; M4 is 25% to 30%; and M5 is 25% to 30%.

[0010] In some embodiments, M1 is 0% to 5%; M2 is 5% to 10%; M3 is 30% to 35%; M4 is 20% to 25%; and M5 is 25% to 30%.

[0011] In some embodiments, M1 is 5% to 10%; M2 is 10% to 15%; M3 is 35% to 40%; M4 is 20% to 25%; and M5 is 20% to 25%.

[0012] In some embodiments, M1 is 5% to 10%; M2 is 10% to 15%; M3 is 35% to 40%; M4 is 15% to 20%; and M5 is 20% to 25%.

[0013] In some embodiments, M1 is 5% to 10%; M2 is 15% to 20%; M3 is 35% to 40%; M4 is 10% to 15%; and M5 is 15% to 20%.

[0014] In some embodiments, M1 is 5% to 10%; M2 is 15% to 20%; M3 is 40% to 50%; M4 is 10% to 15%; and M5 is 10% to 15%.

[0015] In some embodiments, the temperature range of the cryogenic zone is -100°C to -150°C.

[0016] The second aspect of the present application provides a method for preparing the mixed refrigerant provided in the first aspect of the present application, comprising: uniformly mixing the first refrigerant, the second refrigerant, the third refrigerant, the fourth refrigerant and the fifth refrigerant at room temperature to obtain the mixed refrigerant.

[0017] The third aspect of the present application provides an application of the mixed refrigerant provided in the first aspect of the present application in an automatic cascade refrigeration system.

[0018] The present application provides a mixed refrigerant suitable for cryogenic temperature zones, a preparation method thereof, and an application thereof, wherein the mixed refrigerant includes a first refrigerant, a second refrigerant, a third refrigerant, a fourth refrigerant, and a fifth refrigerant; the first refrigerant is argon and / or nitrogen, the second refrigerant is methane and / or krypton, the third refrigerant is selected from at least one of 1,1-difluoroethylene, ethane, and ethylene, the fourth refrigerant is 2,3,3,3-tetrafluoro-1-propylene, and the fifth refrigerant is chlorotrifluoropropylene and / or hexafluoro-2-butene; based on the total molar number of the mixed refrigerant, the mole percentage of the first refrigerant is M1, the mole percentage of the second refrigerant is M2, the mole percentage of the third refrigerant is M3, the mole percentage of the fourth refrigerant is M4, and the mole percentage of the fifth refrigerant is M5, M1 is 0% to 10%; M2 is 5% to 20%; M3 is 25% to 50%; M4 is 10% to 30%; and M5 is 10% to 30%. The present application adopts the above five types of refrigerants and mixes them according to the above ratio. The resulting mixed refrigerant can be used in the deep cold temperature zone of -100°C to -150°C. When used in an automatic cascade refrigeration system, the system temperature can reach -100°C to -150°C, and the automatic cascade refrigeration system can operate normally and efficiently. At the same time, the various refrigerants in the mixed refrigerant are mutually soluble in each other and have good mutual solubility with mineral oil and lubricating oil in the refrigeration system. The obtained mixed refrigerant has an ODP value of 0 and a GWP value of less than 150, and the preparation method is simple. It is non-toxic, environmentally friendly, easy to use, and safe, and is suitable for industrial large-scale production and application.

[0019] Of course, it is not necessary to achieve all the advantages described above at the same time when implementing any product or method of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

[0021] Figure 1This is a schematic structural diagram of a five-stage automatic cascade refrigeration system used for the mixed refrigerant in Examples 1-6 of the present application. In the figure, 1. first heat exchanger, 2. second heat exchanger, 3. third heat exchanger, 4. fourth heat exchanger, 5. fifth heat exchanger, 210. solenoid valve, 310. capillary tube, 410. filter, 510. gas-liquid separator, 610. pressure gauge, 710. pressure sensor, 810. temperature sensor, 910. load, 1010. compressor, 1110. oil separator, 1210. condenser, 1310. buffer tank. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present application and the accompanying drawings to clearly and completely describe the technical solutions in this application. Obviously, the embodiments described are only part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0023] A first aspect of the present application provides a mixed refrigerant suitable for use in a cryogenic temperature zone, wherein the mixed refrigerant comprises a first refrigerant, a second refrigerant, a third refrigerant, a fourth refrigerant, and a fifth refrigerant;

[0024] The first refrigerant is argon and / or nitrogen, the second refrigerant is methane and / or krypton, the third refrigerant is at least one selected from 1,1-difluoroethylene, ethane, and ethylene, the fourth refrigerant is 2,3,3,3-tetrafluoro-1-propene, and the fifth refrigerant is monochlorotrifluoropropene and / or hexafluoro-2-butene;

[0025] Based on the total molar number of the mixed refrigerant, the mole percentage of the first refrigerant is M1, the mole percentage of the second refrigerant is M2, the mole percentage of the third refrigerant is M3, the mole percentage of the fourth refrigerant is M4, and the mole percentage of the fifth refrigerant is M5, M1 is 0% to 10%; M2 is 5% to 20%; M3 is 25% to 50%; M4 is 10% to 30%; M5 is 10% to 30%. For example, the M1 can be 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or a range consisting of any two of the values; the M2 can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or a range consisting of any two of the values; the M3 can be 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 35%, 36%, 38%, 40%, 42%, 43%, 45%, 46%, 48%, 50%, or a range consisting of any two of the values. % , 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or a range consisting of any two of the values; M5 can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or a range consisting of any two of the values. In this application, the sum of the mole percentages of the above five types of refrigerants in the mixed refrigerant is 100%.

[0026] Compared with existing mixed refrigerants, the mixed refrigerant of the present application has the following advantages: 1. Compliance with strict environmental protection requirements: The mixed refrigerant of the present application has an ODP value of 0 and a GWP value of less than 150, and has excellent environmental performance. 2. Good fluidity at low temperatures: The mixed refrigerant of the present application has good mutual solubility with the mineral oil and polyol ester lubricant (POE oil) used in the refrigeration system, and has good fluidity at low temperatures of -100°C to -150°C. When flowing through the capillary tubes and expansion valve throttling devices in the refrigeration system at low temperatures, there will be no oil solidification or wax blockage; and the temperature at which the mixed refrigerant solidifies is lower than -150°C. 3. Non-toxic and safe: In the present application, the refrigerants used are all non-toxic. The refrigerants hexafluoro-2-butene, argon, krypton, and nitrogen are all non-flammable refrigerants, and 1,1-difluoroethylene, monochlorotrifluoropropylene, and 2,3,3,3-tetrafluoro-1-propylene are all slightly flammable refrigerants. Among them, 2,3,3,3-tetrafluoro-1-propene, while slightly flammable, requires the presence of gasoline to ignite, making it safe to use as a refrigerant. Refrigerants like methane, ethane, and ethylene are flammable refrigerants. This application controls the proportion of flammable refrigerants in the mixed refrigerant, making the mixed refrigerant less hazardous and more secure.

[0027] In the present application, the molar amount of each refrigerant can be adjusted to control the molar percentage of each refrigerant in the mixed refrigerant, so that the mixed refrigerant can be applied to different cryogenic temperature zones.

[0028] In some embodiments, M1 is 0% to 5%; M2 is 5% to 10%; M3 is 25% to 30%; M4 is 25% to 30%; and M5 is 25% to 30%. The mixed refrigerant is suitable for use in a cryogenic temperature range of -100°C to -105°C.

[0029] In some embodiments, M1 is 0% to 5%; M2 is 5% to 10%; M3 is 30% to 35%; M4 is 20% to 25%; and M5 is 25% to 30%. The mixed refrigerant is suitable for use in a cryogenic temperature range of -105°C to -115°C.

[0030] In some embodiments, M1 is 5% to 10%; M2 is 10% to 15%; M3 is 35% to 40%; M4 is 20% to 25%; and M5 is 20% to 25%. The mixed refrigerant is suitable for use in a cryogenic temperature range of -115°C to -125°C.

[0031] In some embodiments, M1 is 5% to 10%; M2 is 10% to 15%; M3 is 35% to 40%; M4 is 15% to 20%; and M5 is 20% to 25%. The mixed refrigerant is suitable for use in a cryogenic temperature range of -125°C to -135°C.

[0032] In some embodiments, M1 is 5% to 10%; M2 is 15% to 20%; M3 is 35% to 40%; M4 is 10% to 15%; and M5 is 15% to 20%. The mixed refrigerant is suitable for use in a cryogenic temperature range of -135°C to -145°C.

[0033] In some embodiments, M1 is 5% to 10%; M2 is 15% to 20%; M3 is 40% to 50%; M4 is 10% to 15%; and M5 is 10% to 15%. The mixed refrigerant is suitable for use in a cryogenic temperature range of -145°C to -150°C.

[0034] In some embodiments, the temperature range of the cryogenic temperature zone is -100° C. to -150° C. The mixed refrigerant described in the present application is suitable for the cryogenic temperature range of -100° C. to -150° C.

[0035] In some embodiments, the first refrigerant is argon (R740) and / or nitrogen (R728).

[0036] In some embodiments, the second refrigerant is methane (R50) and / or krypton (R83).

[0037] In some embodiments, the third refrigerant is selected from at least one of 1,1-difluoroethylene (R1132a), ethane (R170), and ethylene (R1150).

[0038] In some embodiments, the fourth refrigerant is 2,3,3,3-tetrafluoro-1-propene (R1234yf).

[0039] In some embodiments, the fifth refrigerant is chlorotrifluoropropylene (R1233zd) and / or hexafluoro-2-butene (R1336mzz).

[0040] As used herein, GWP (Global Warming Potential) refers to the greenhouse effect of a greenhouse gas relative to the mass of carbon dioxide (CO2) with the same effect over a 100-year timeframe. A higher GWP indicates a greater greenhouse effect per unit mass per unit time. The GWP, ODP, and molecular weight of each refrigerant used in this application are shown in Table 1.

[0041] Table 1

[0042] Refrigerant code Chemical name GWP value (100y) ODP value Molecular weight R740 Argon 0 0 39.95 R728 Nitrogen 0 0 28.01 R83 krypton 0 0 83.798 R50 methane 28 0 16.043 R1132a 1,1-Difluoroethylene 0 0 64.034 R170 Ethane 10 0 30.07 R1150 Ethylene 6 0 28.054 R1234yf 2,3,3,3-tetrafluoro-1-propene 4 0 114.0416 R1233zd Chlorotrifluoropropene 1 0 130.4962 R1336mzz Hexafluoro-2-butene 7 0 164.049

[0043] The second aspect of the present application provides a method for preparing a mixed refrigerant provided in accordance with the first aspect of the present application, comprising: uniformly mixing the first refrigerant, the second refrigerant, the third refrigerant, the fourth refrigerant, and the fifth refrigerant at room temperature to obtain the mixed refrigerant. In the present application, the room temperature is room temperature, which is 20°C-30°C. The method for preparing a mixed refrigerant provided in the present application comprises uniformly mixing the above five types of refrigerants at room temperature in a reasonable proportion, thereby simplifying the preparation method.

[0044] The third aspect of the present application provides a use of the mixed refrigerant provided in the first aspect of the present application in an auto-cascade refrigeration system. In some embodiments, the use includes: adding the mixed refrigerant to the auto-cascade refrigeration system.

[0045] Example

[0046] Hereinafter, the embodiments of the present application will be described in more detail with reference to examples. Various tests and evaluations were performed according to the following methods.

[0047] Calculation method for GWP value of mixed refrigerants:

[0048] Taking Example 1 as an example, 1. GWP value of mixed refrigerants

[0049] Calculation method of ODP value of mixed refrigerant:

[0050]

[0051] Application of mixed refrigerants in five-stage automatic cascade refrigeration system:

[0052] The structural diagram of the five-stage automatic cascade refrigeration system used in the mixed refrigerant of Examples 1-6 is as follows: Figure 1 As shown, the mixed refrigerant is added to the refrigeration system, and the operating parameters are set: condensing temperature and refrigeration temperature. The reagent of the condenser 1210 is water (H2O). The mixed refrigerant flows to the first heat exchanger 1, the second heat exchanger 2, the third heat exchanger 3, the fourth heat exchanger 4 and the fifth heat exchanger 5 for heat exchange. When the refrigeration system is running, the high pressure exhaust pressure of the compressor 1010 is lower than the upper limit of 300psi, indicating that the refrigeration system is operating normally. While ensuring the normal lubrication and safe operation of the refrigeration system, the refrigeration system reaches the deep cold temperature zone of -100℃ to -150℃.

[0053] Example 1

[0054] A mixed refrigerant for use at -100°C is configured by uniformly mixing a first refrigerant, a second refrigerant, a third refrigerant, a fourth refrigerant, and a fifth refrigerant at a molar ratio of 0:10:30:30:30 at room temperature to obtain the mixed refrigerant. Based on the total moles of the mixed refrigerant, the mole percentage M1 of the first refrigerant is 0%; the mole percentage M2 of the second refrigerant is 10%; the mole percentage M3 of the third refrigerant is 30%; the mole percentage M4 of the fourth refrigerant is 30%; and the mole percentage M5 of the fifth refrigerant is 10% R1336mzz, 20% R1233zd, and 30% R1336mzz. The calculated GWP of the mixed refrigerant is 2.66, and the ODP is 0.

[0055] The mixed refrigerant is added to the automatic cascade refrigeration system. The operating parameters of the refrigeration system are: condensing temperature 25℃, refrigeration temperature -100℃, compressor exhaust pressure high pressure 160psi, low pressure 25psi, and the pressure is lower than the upper limit of 300psi. The refrigeration system can operate normally, indicating that the mixed refrigerant is suitable for -100℃ refrigeration.

[0056] Example 2

[0057] A mixed refrigerant configured for use at -110°C is prepared by uniformly mixing a first refrigerant, a second refrigerant, a third refrigerant, a fourth refrigerant, and a fifth refrigerant at a molar ratio of 3:10:32:25:30 at room temperature to obtain the mixed refrigerant. Based on the total moles of the mixed refrigerant, the first refrigerant is R740 with a mole percentage M1 of 3%; the second refrigerant is R83 at 5% mole percentage, R50 at 5% mole percentage, and M2 of 10% mole percentage; the third refrigerant is R170 with a mole percentage M3 of 32%; the fourth refrigerant is R1234yf with a mole percentage M4 of 25%; and the fifth refrigerant is R1336mzz at 15% mole percentage, R1233zd at 15% mole percentage, and M5 of 30% mole percentage. Calculated GWP of the mixed refrigerant is 4.80 and ODP is 0.

[0058] The mixed refrigerant is added to the automatic cascade refrigeration system. The operating parameters of the refrigeration system are: condensing temperature 25℃, refrigeration temperature -110℃, compressor exhaust pressure high pressure 180psi, low pressure 30psi, and the pressure is lower than the upper limit of 300psi. The refrigeration system can operate normally, indicating that the mixed refrigerant is suitable for -110℃ refrigeration.

[0059] Example 3

[0060] A mixed refrigerant for use at -120°C is configured by uniformly mixing a first refrigerant, a second refrigerant, a third refrigerant, a fourth refrigerant, and a fifth refrigerant at a molar ratio of 5:12:38:20:25 at room temperature to produce the mixed refrigerant. Based on the total moles of the mixed refrigerant, the first refrigerant is R740 with a mole percentage M1 of 5%; the second refrigerant is R50 with a mole percentage M2 of 12%; the third refrigerant comprises R1132a at 15% mole percentage, R1150 at 23% mole percentage, and M3 of 38%; the fourth refrigerant is R1234yf with a mole percentage M4 of 20%; and the fifth refrigerant comprises R1233zd at 15% mole percentage, R1336mzz at 10% mole percentage, and M5 of 25%. Calculated global warming potential (GWP) of the mixed refrigerant is 4.04, and its average annual distribution (ODP) value is 0.

[0061] The mixed refrigerant is added to the automatic cascade refrigeration system. The operating parameters of the refrigeration system are: condensing temperature 25℃, refrigeration temperature -120℃, compressor exhaust pressure high pressure 190psi, low pressure 28psi, and the pressure is lower than the upper limit of 300psi. The refrigeration system can operate normally, indicating that the mixed refrigerant is suitable for -120℃ refrigeration.

[0062] Example 4

[0063] A mixed refrigerant configured for use at -130°C is prepared by uniformly mixing a first refrigerant, a second refrigerant, a third refrigerant, a fourth refrigerant, and a fifth refrigerant at a molar ratio of 10:10:35:20:25 at room temperature to obtain the mixed refrigerant. Based on the total moles of the mixed refrigerant, the first refrigerant comprises 8% R740 and 2% R728, with a mole percentage M1 of 10%; the second refrigerant comprises 7% R83 and 3% R50, with a mole percentage M2 of 10%; the third refrigerant comprises R1150, with a mole percentage M3 of 35%; the fourth refrigerant comprises R1234yf, with a mole percentage M4 of 20%; and the fifth refrigerant comprises R1336mzz, with a mole percentage M5 of 25%. The calculated GWP of the mixed refrigerant is 5.38 and the ODP is 0.

[0064] The mixed refrigerant is added to the automatic cascade refrigeration system. The operating parameters of the refrigeration system are: condensing temperature 25℃, refrigeration temperature -130℃, compressor exhaust pressure high pressure 210psi, low pressure 28psi, and the pressure is lower than the upper limit of 300psi. The refrigeration system can operate normally, indicating that the mixed refrigerant is suitable for -130℃ refrigeration.

[0065] Example 5

[0066] A mixed refrigerant configured for use at -140°C is prepared by uniformly mixing a first refrigerant, a second refrigerant, a third refrigerant, a fourth refrigerant, and a fifth refrigerant at a molar ratio of 10:20:35:15:20 at room temperature to obtain the mixed refrigerant. Based on the total moles of the mixed refrigerant, the first refrigerant is R740 with a mole percentage M1 of 10%; the second refrigerant comprises 10% R83 and 10% R50, with a mole percentage M2 of 20%; the third refrigerant is R1150 with a mole percentage M3 of 35%; the fourth refrigerant is R1234yf with a mole percentage M4 of 15%; and the fifth refrigerant is R1336mzz with a mole percentage M5 of 20%. Calculated global warming potential (GWP) of the mixed refrigerant is 5.45, and its average annual distribution (ODP) value is 0.

[0067] The mixed refrigerant is added to the automatic cascade refrigeration system. The operating parameters of the refrigeration system are: condensing temperature 25℃, refrigeration temperature -140℃, compressor exhaust pressure high pressure 215psi, low pressure 25psi, and the pressure is lower than the upper limit of 300psi. The refrigeration system can operate normally, indicating that the mixed refrigerant is suitable for -140℃ refrigeration.

[0068] Example 6

[0069] A mixed refrigerant for use at -150°C is configured by uniformly mixing a first refrigerant, a second refrigerant, a third refrigerant, a fourth refrigerant, and a fifth refrigerant at a molar ratio of 10:20:40:15:15 at room temperature to produce the mixed refrigerant. Based on the total moles of the mixed refrigerant, the first refrigerant comprises 7% R740, 3% R728, and a mole percentage M1 of 10%; the second refrigerant comprises R50, with a mole percentage M2 of 20%; the third refrigerant comprises R1150, with a mole percentage M3 of 40%; the fourth refrigerant comprises R1234yf, with a mole percentage M4 of 15%; and the fifth refrigerant comprises 5% R1336mzz, 10% R1233zd, and a mole percentage M5 of 15%. Calculated global warming potential (GWP) of the mixed refrigerant is 5.25, and an optical density (ODP) of 0.

[0070] The mixed refrigerant is added to the automatic cascade refrigeration system. The operating parameters of the refrigeration system are: condensing temperature 25℃, refrigeration temperature -150℃, compressor exhaust pressure high pressure 215psi, low pressure 23psi, and the pressure is lower than the upper limit of 300psi. The refrigeration system can operate normally, indicating that the mixed refrigerant is suitable for -150℃ refrigeration.

[0071] In summary, the mixed refrigerant provided in this application has an ODP value of 0 and a GWP value of less than 30, and is suitable for automatic cascade refrigeration systems with a refrigeration temperature range of -100°C to -150°C, achieving the effects of being non-toxic, environmentally friendly, convenient and safe.

[0072] It should be noted that, in this article, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method or article comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method or article. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method or article comprising the element.

[0073] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A mixed refrigerant suitable for cryogenic temperature range, wherein: The mixed refrigerant includes a first refrigerant, a second refrigerant, a third refrigerant, a fourth refrigerant and a fifth refrigerant; The first refrigerant is argon and / or nitrogen, the second refrigerant is methane and / or krypton, the third refrigerant is at least one selected from 1,1-difluoroethylene, ethane, and ethylene, the fourth refrigerant is 2,3,3,3-tetrafluoro-1-propene, and the fifth refrigerant is monochlorotrifluoropropene and / or hexafluoro-2-butene; Based on the total molar number of the mixed refrigerant, the mole percentage of the first refrigerant is M1, the mole percentage of the second refrigerant is M2, the mole percentage of the third refrigerant is M3, the mole percentage of the fourth refrigerant is M4, and the mole percentage of the fifth refrigerant is M5. M1 is 0% to 10%; M2 is 5% to 20%; M3 is 25% to 50%; M4 is 10% to 30%; M5 is 10% to 30%.

2. The mixed refrigerant according to claim 1, wherein M1 is 0% to 5%; M2 is 5% to 10%; M3 is 25% to 30%; M4 is 25% to 30%; M5 is 25% to 30%.

3. The mixed refrigerant according to claim 1, wherein M1 is 0% to 5%; M2 is 5% to 10%; M3 is 30% to 35%; M4 is 20% to 25%; M5 is 25% to 30%.

4. The mixed refrigerant according to claim 1, wherein M1 is 5% to 10%; M2 is 10% to 15%; M3 is 35% to 40%; M4 is 20% to 25%; M5 is 20% to 25%.

5. The mixed refrigerant according to claim 1, wherein M1 is 5% to 10%; M2 is 10% to 15%; M3 is 35% to 40%; M4 is 15% to 20%; M5 is 20% to 25%.

6. The mixed refrigerant according to claim 1, wherein M1 is 5% to 10%; M2 is 15% to 20%; M3 is 35% to 40%; M4 is 10% to 15%; M5 is 15% to 20%.

7. The mixed refrigerant according to claim 1, wherein: M1 is 5% to 10%; M2 is 15% to 20%; M3 is 40% to 50%; M4 is 10% to 15%; M5 is 10% to 15%.

8. The mixed refrigerant according to any one of claims 1 to 7, wherein: The temperature range of the deep cooling zone is -100°C to -150°C.

9. A method for preparing a mixed refrigerant according to any one of claims 1 to 8, comprising: The first refrigerant, the second refrigerant, the third refrigerant, the fourth refrigerant and the fifth refrigerant are uniformly mixed at room temperature to obtain the mixed refrigerant.

10. Use of the mixed refrigerant according to any one of claims 1 to 8 in an auto-cascade refrigeration system.

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