Mixed refrigerant and application thereof

Abstract

The invention belongs to the technical field of refrigerants, and discloses a mixed refrigerant and application thereof, the mixed refrigerant is composed of two or three of ethane, propane, propylene and difluoroethane; when the component contains ethane, the mass percent of the ethane in the mixed refrigerant is not more than 10% or 21-50%; when difluoroethane is contained in the components, the mass percent of the difluoroethane in the mixed refrigerant is 65-85%. By improving the components of the mixed refrigerant and the proportion of all the components, the technical problems that an existing refrigerant is high in GWP value, low in energy efficiency and low in refrigerating capacity per unit volume and affects the refrigerating performance can be solved, and the mixed refrigerant can be used for replacing R32 or R290, is low in exhaust temperature, large in refrigerating capacity per unit volume and small in refrigerant charging amount and can be used for replacing R32 refrigerants, R410A refrigerants and other high GWP refrigerants.

Description

Technical Field

[0001] The present invention belongs to the technical field of refrigerants, and more specifically, relates to a mixed refrigerant and an application thereof. The mixed refrigerant is an environmentally friendly mixed refrigerant that can replace R32 or R410A. Background Art

[0002] As people pay more attention to the depletion of the ozone layer and the intensification of the greenhouse effect, countries around the world have gradually phased out chlorine-containing refrigerants with an ODP greater than zero, and have begun to restrict the use of hydrofluorocarbon (HFC) refrigerants with high global warming potential (GWP). In October 2016, the Kigali Amendment to the Montreal Protocol clarified the control of 18 HFCs, and the task of finding alternative refrigerants with excellent performance is urgent.

[0003] In recent years, difluoromethane (R32) has been widely used in the field of household air conditioning as a transitional substitute for R410A. It has a higher unit volumetric cooling capacity and system application performance coefficient (COP) and a lower GWP. However, according to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR6), the GWP of R32 was revised to 771, which is higher than the limit of the European Parliament's fluorinated gas regulation (F-gas) for refrigerants used in household air conditioners. According to the regulations of the European Parliament, after 2025, fluorinated greenhouse gases with a GWP of 750 or higher will be banned in split air conditioning systems with a charge of less than 3 kg. Therefore, research on alternatives to R32 used in air conditioners is also imminent.

[0004] Currently, one of the main ideas for replacing R32 refrigerants is natural refrigerant propane (R290). However, the unit volume cooling capacity of air-conditioning systems using R290 as refrigerant is too low, the energy efficiency needs to be further improved, and the charging amount is strictly limited. Therefore, new refrigerants are urgently needed to solve the above problems.

[0005] Professor He Guogeng reported a binary mixed refrigerant constructed by using ethane and propylene (see Chinese patent application CN114752357A), in which the mass percentage of ethane is 11% to 20% and the mass percentage of propylene is 89% to 80%, which can replace R32 and R410a refrigerants. Although this refrigerant can replace R32 to a certain extent, this new refrigerant still has room for improvement in system energy efficiency, unit volume refrigeration capacity and safety (the components of this refrigerant are all highly flammable refrigerants like R290, and the safety of pure R290 has not been improved).

[0006] In addition, Professor He Guogeng reported a ternary mixed refrigerant constructed by using ethane, propylene and propane (see Chinese patent application CN114752356A), in which ethane 12% to 20.5%, propylene 75.5% to 87% and propane 1% to 4%, can also replace R32 and R410a refrigerants. Although this refrigerant can replace R32 to a certain extent, this new refrigerant still has room for improvement in system energy efficiency, unit volume refrigeration capacity and safety (the components of this refrigerant are all highly flammable refrigerants like R290, and the safety of pure R290 has not been improved). Summary of the invention

[0007] In view of the above defects or improvement needs of the prior art, the object of the present invention is to provide a mixed refrigerant and its application, wherein by improving the components of the mixed refrigerant and the proportion of each component, it is possible to solve the technical problems of the existing refrigerants having high GWP value, low energy efficiency, low refrigeration capacity per unit volume, and affecting refrigeration performance. The refrigerant obtained by the present invention is a mixed refrigerant, which is an energy-saving and environmentally friendly refrigerant with high energy efficiency. It can be used to replace R32 or R290 (even directly replace R32 or R290 without replacing refrigeration components), has low exhaust temperature, large refrigeration capacity per unit volume, and small refrigerant charge. The ODP value of the present invention is 0, the GWP value is less than 150, the environmental protection advantage is outstanding, and it has broad application prospects. It can be used to replace high GWP refrigerants such as R32 and R410A. It is applicable to refrigeration equipment such as household and commercial air-conditioning systems, heat pump water heaters, cold storage refrigeration, and automotive air conditioners.

[0008] To achieve the above object, according to one aspect of the present invention, there is provided a mixed refrigerant consisting of two or three of ethane, propane, propylene and difluoroethane;

[0009] When ethane is included in the components, the mass percentage of ethane in the mixed refrigerant does not exceed 10%, or is 21% to 50%;

[0010] When difluoroethane is included in the components, the mass percentage of difluoroethane in the mixed refrigerant is 65 to 85%.

[0011] As a further preferred embodiment of the present invention, the mixed refrigerant is composed of at least one of propane and propylene and difluoroethane, and the mass percentage of difluoroethane in the mixed refrigerant is 65-85%.

[0012] As a further preferred embodiment of the present invention, the mixed refrigerant is composed of ethane and at least one of propane and propylene; and the mass percentage of ethane in the mixed refrigerant does not exceed 10%, or is 21% to 50%.

[0013] As a further preferred embodiment of the present invention, the mixed refrigerant consists of three components: ethane, propane and propylene, and the mass ratio of ethane, propane and propylene in the mixed refrigerant is 0.1:0.05:0.85, or 0.21:0.64:0.15, or 0.25:0.1:0.65, or 0.25:0.25:0.5, or 0.35:0.05:0.6, or 0.5:0.05:0.45.

[0014] As a further preferred embodiment of the present invention, the mixed refrigerant consists of two components, ethane and propylene, and the mass ratio of ethane and propylene in the mixed refrigerant is 0.05:0.95, or 0.1:0.9, or 0.21:0.79, or 0.25:0.75, or 0.3:0.7, or 0.4:0.6, or 0.5:0.5.

[0015] As a further preferred embodiment of the present invention, the mixed refrigerant consists of two components, ethane and propane, and the mass ratio of ethane to propane in the mixed refrigerant is 0.21:0.79, or 0.25:0.75.

[0016] As a further preferred embodiment of the present invention, the mixed refrigerant consists of three components: propane, propylene and difluoroethane, and the mass ratio of propane, propylene and difluoroethane in the mixed refrigerant is 0.05:0.1:0.85, or 0.05:0.3:0.65, or 0.1:0.05:0.85, or 0.3:0.05:0.65.

[0017] As a further preferred embodiment of the present invention, the mixed refrigerant is composed of two components, propane and difluoroethane, and the mass ratio of propane to difluoroethane in the mixed refrigerant is 0.2:0.8, or 0.25:0.75, or 0.3:0.7;

[0018] Alternatively, the mixed refrigerant consists of two components, propylene and difluoroethane, and the mass ratio of propylene to difluoroethane in the mixed refrigerant is 0.2:0.8, or 0.3:0.7.

[0019] According to another aspect of the present invention, the present invention provides the use of the above mixed refrigerant as a refrigerant.

[0020] As a further preferred embodiment of the present invention, the mixed refrigerant is used as a refrigerant for household air conditioners, central air conditioners, heat pump water heaters, cold storage or automotive air conditioners; preferably, the application is to replace R32, R410A or R22 refrigerants.

[0021] Compared with the prior art, the above technical solutions conceived by the present invention can achieve the following

[0022] Beneficial effects:

[0023] 1. The refrigerant used in the present invention has a low GWP value. Within the mass concentration range of the mixture involved in the present invention, the GWP value of the mixture does not exceed 150, which meets the requirements of the EU F-gas regulations for alternative refrigerants. Compared with R32 and R410A, the present invention is environmentally friendly and has broad application prospects.

[0024] 2. The COP value of the refrigerant provided by the present invention is higher than that of R32 and R410A, and has the advantage of significant energy saving and emission reduction.

[0025] 3. The present invention can be preferably composed of at least one of propane and propylene and ethane, and the mass percentage of ethane in the mixed refrigerant is not more than 10% or is 21% to 50%. The working pressure and unit volume refrigeration capacity of the refrigerant obtained by these preferred formulas are close to those of R32 and R410A, higher than those of R290, and can be directly used to replace R32 and R410A without replacing too many parts, or only some parts can be changed. At the same time, based on the present invention, it can be preferably composed of at least one of propane and propylene and difluoroethane, and the mass percentage of difluoroethane in the mixed refrigerant is 65 to 85%. The working pressure and unit volume refrigeration capacity of the refrigerant obtained by these preferred formulas are close to those of R290, and can be directly used to replace R290 without replacing too many parts, or only some parts can be changed.

[0026] 4. The refrigerant provided by the present invention has a lower exhaust temperature than R32, which is beneficial to the operation of the refrigeration compressor and makes the refrigeration compressor have higher reliability.

[0027] 5. The present invention may preferably use a mixed refrigerant consisting of at least one of propane and propylene and difluoroethane, and the mass percentage of difluoroethane in the mixed refrigerant is 65-85%. The flammability of the refrigerants obtained corresponding to these preferred formulations is weaker than that of R290 and the prior art CN114752357A and CN114752356A, thereby improving safety.

[0028] 6. The refrigerant provided by the present invention can fill the gap in the alternative solutions for R32 and R410A refrigerants, and solve the problems of low unit volume refrigeration capacity and energy efficiency of R290 refrigerant. It is of great significance for the development of environmentally friendly refrigerants in the field of low-temperature refrigeration in my country, and for accelerating the elimination and replacement of high GWP refrigerants.

[0029] Compared with CN114752357A and CN114752356A, although both are environmentally friendly mixed refrigerants that can replace R32 or R410A, the present invention overcomes the composition and ratio limitations of these prior arts, and obtains more mixed refrigerants that are more conducive to refrigeration cycle performance. The present invention is optimized in terms of system energy efficiency, unit volume refrigeration capacity and safety relative to the prior art. Based on the non-azeotropic mixed refrigerant obtained by the present invention, a refrigeration air conditioner using the non-azeotropic mixed refrigerant as a working fluid can be further constructed. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] The mixed refrigerant of the present invention is composed of two or three of ethane, propane, propylene and difluoroethane; the mass percentage of ethane in the mixed refrigerant is 0-10% or 21%-50%, and the mass percentage of difluoroethane is 0 or 65-85%.

[0032] The basic physical properties of the four components are shown in Table 1.

[0033] Table 1: Basic physical properties of the four components

[0034] Components Ethane Propane Propylene Difluoroethane Code R170 R290 R1270 R152a Molecular formula <![CDATA[C2H6]]> <![CDATA[C3H8]]> <![CDATA[C3H6]]> <![CDATA[C2H4F2]]> Relative molecular weight 30.069 44.096 42.08 66.051 Latent heat of vaporization (1atm) kJ / kg 489.41 425.60 438.89 329.92 Standard boiling point℃ -88.586 -42.119 -47.625 -24.027 Critical pressure kPa 4872.2 4251.2 4555.0 4516.8 Critical temperature℃ 32.172 96.74 91.061 113.26 <![CDATA[Critical density kg / m 3 > 206.18 220.48 229.63 368.0 ODP 0 0 0 0 GWP ～20 ～20 ～20 124

[0035] Based on the present invention, the mixed refrigerant formed by the above components can be prepared by conventional methods in the prior art, for example, comprising the following steps: mixing gaseous ethane, gaseous propane, gaseous propylene and gaseous difluoroethane in proportion to obtain the mixed refrigerant.

[0036] For another example, the preparation method may also include the following steps: liquid ethane, liquid propane, liquid propylene and liquid difluoroethane are uniformly mixed according to a certain proportion to obtain the mixed refrigerant.

[0037] The above refrigerants can be dissolved in each other according to the principle of like dissolves like, and thus can be charged into the refrigerant tank in the order of boiling point from high to low according to the weight ratio for physical mixing. Alternatively, they can be charged into the compressor in the order of boiling point from high to low according to the weight ratio, and can be used after being evenly mixed.

[0038] The following are specific embodiments:

[0039] Example 1: Take ethane, propane and propylene refrigerants commonly used in the refrigerant field, and in a liquid state, take 10% by mass of ethane, 5% by mass of propane and 85% by mass of propylene for thorough physical mixing to obtain a mixed refrigerant.

[0040] Example 2: Take ethane, propane and propylene refrigerants commonly used in the refrigerant field, and in a liquid state, take 21% by mass ethane, 64% by mass propane and 15% by mass propylene for thorough physical mixing to obtain a mixed refrigerant.

[0041] Example 3: Take ethane, propane and propylene refrigerants commonly used in the refrigerant field, and in a liquid state, take 25% by mass of ethane, 10% by mass of propane and 65% by mass of propylene for thorough physical mixing to obtain a mixed refrigerant.

[0042] Example 4: Take ethane and propylene refrigerants commonly used in the refrigerant field, and in a liquid state, take 5% by mass ethane and 95% by mass propylene for thorough physical mixing to obtain a mixed refrigerant.

[0043] Example 5: Take ethane and propylene refrigerants commonly used in the refrigerant field, and in a liquid state, take 25% by mass ethane and 75% by mass propylene for thorough physical mixing to obtain a mixed refrigerant.

[0044] Example 6: Take ethane and propylene refrigerants commonly used in the refrigerant field, and in a liquid state, take 50% by mass ethane and 50% by mass propylene for thorough physical mixing to obtain a mixed refrigerant.

[0045] Example 7: Take ethane and propane refrigerants commonly used in the refrigerant field, and in a liquid state, take 21% by mass ethane and 79% by mass propane for thorough physical mixing to obtain a mixed refrigerant.

[0046] Example 8: Take ethane and propane refrigerants commonly used in the refrigerant field, and in a liquid state, take 25% by mass ethane and 75% by mass propane and fully physically mix them to obtain a mixed refrigerant.

[0047] Example 9: Take propane, propylene and difluoroethane refrigerants commonly used in the refrigerant field, and in a liquid state, take 5% by mass of propane, 10% by mass of propylene and 85% by mass of difluoroethane for thorough physical mixing to obtain a mixed refrigerant.

[0048] Example 10: Take propane, propylene and difluoroethane refrigerants commonly used in the refrigerant field, and in a liquid state, take 30% by mass of propane, 5% by mass of propylene and 65% by mass of difluoroethane and fully physically mix them to obtain a mixed refrigerant.

[0049] Example 11: Take propane and difluoroethane refrigerants commonly used in the refrigerant field, and in a liquid state, take 20% by mass of propane and 80% by mass of difluoroethane and fully physically mix them to obtain a mixed refrigerant.

[0050] Example 12: Take propylene and difluoroethane refrigerants commonly used in the refrigerant field, and in a liquid state, take 20% by mass of propylene and 80% by mass of difluoroethane and fully physically mix them to obtain a mixed refrigerant.

[0051] Comparative Example 1: Take ethane, propane and propylene refrigerants commonly used in the refrigerant field, and in a liquid state, take 80% by mass of ethane, 10% by mass of propane and 10% by mass of propylene for thorough physical mixing to obtain a mixed refrigerant.

[0052] Comparative Example 2: Take propane, propylene and difluoroethane refrigerants commonly used in the refrigerant field, and in a liquid state, take 30% by mass of propane, 50% by mass of propylene and 20% by mass of difluoroethane for thorough physical mixing to obtain a mixed refrigerant.

[0053] In order to compare the performance, the above embodiment is used to perform theoretical cycle calculation of the air conditioning system with R32 and R290, and the refrigeration conditions of the air conditioner are: evaporation temperature is 10°C, condensation temperature is 47°C, condenser outlet temperature is 38°C, compressor inlet temperature is 20°C, and compressor isentropic efficiency is 0.8. The present invention focuses on optimizing the refrigeration conditions of the air conditioner. In actual production, the air conditioner using non-azeotropic mixed refrigerant as the working fluid may have the problem of too low evaporator inlet temperature and frosting affecting performance during winter heating conditions. Therefore, in the calculation of the cycle, the evaporator inlet temperature during heating conditions is also concerned (the evaporator inlet temperature, if too low, will cause the outdoor unit evaporator to frost during heating operation, and frosting will reduce the system energy efficiency during actual operation). The heating conditions are: evaporation temperature is 2°C, condensation temperature is 45°C, condenser outlet temperature is 35°C, compressor inlet temperature is 5°C, and compressor isentropic efficiency is 0.8. The calculated parameters are shown in Tables 2 and 3 below.

[0054] Table 2: Refrigeration cycle performance parameters of R32, R290 and Examples 1 to 6

[0055]

[0056] Table 3: Refrigeration cycle performance parameters of Examples 7 to 12 and Comparative Examples 1 to 2

[0057]

[0058]

[0059] According to the theoretical calculation results of the above working conditions, it can be concluded that:

[0060] 1. The COP of the refrigerants provided in Examples 1 to 12 of the present invention is higher than that of R32 and R290, and the COP of R32 is increased by 22.2% at most, which has significant benefits of energy saving and emission reduction.

[0061] 2. The unit volumetric refrigeration capacity of the refrigerants provided in Examples 1 to 12 of the present invention, except for Example 9, is higher than that of R290; and the unit volumetric refrigeration capacity of Examples 3 and 5 is close to that of R32 (correspondingly, they are feasible for directly replacing R32 and R410A in working conditions without replacing system components); the unit volumetric refrigeration capacity of Example 6 is 19.5% higher than that of R32, which has a great advantage in terms of unit volumetric refrigeration capacity (correspondingly, although it is not a direct replacement for R32 and R410A in working conditions, it is worthwhile to redesign system components for this formulation).

[0062] 3. The exhaust temperature of the refrigerant provided in Examples 1 to 12 of the present invention is about 30° C. lower than the exhaust temperature of R32, which is beneficial to the operation of the compressor and the refrigeration compressor has higher reliability.

[0063] 4. Under the same working conditions, the condensing pressure, evaporating pressure and unit volume refrigeration capacity of Examples 1 to 5 and 7 to 8 of the present invention are close to those of R32, and the COP is higher than that of R32, and they are feasible to directly replace R32 and R410A under working conditions (without replacing system components); the condensing pressure, evaporating pressure and unit volume refrigeration capacity of Examples 9 to 12 are close to those of R290, and the COP is higher than that of R290, and they are feasible to directly replace R290 under working conditions (without replacing system components). The improvement of COP means that energy efficiency can be improved.

[0064] 5. The four components used in the present invention are all environmentally friendly refrigerants, have no ozone layer damage, and have extremely low greenhouse effect. The GWP of the above embodiments does not exceed 150, meeting the requirements of the EU F-gas regulations for environmentally friendly refrigerants for household air conditioners. The present invention can be widely used in various fields of refrigeration, especially in refrigeration devices such as household air conditioners and central air conditioners, heat pump water heaters, cold storage or automobile air conditioners.

[0065] 6. In addition, based on the present invention, for the embodiments using difluoroethane (eg, embodiments 9 to 12), since difluoroethane is a weakly flammable substance, the flammability of the mixture is reduced, which can improve safety.

[0066] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A mixed refrigerant, characterized in that: It is composed of two or three of ethane, propane, propylene and difluoroethane; When ethane is included in the components, the mass percentage of ethane in the mixed refrigerant does not exceed 10%, or is 21% to 50%; When difluoroethane is included in the components, the mass percentage of difluoroethane in the mixed refrigerant is 65 to 85%.

2. The mixed refrigerant according to claim 1, characterized in that: The mixed refrigerant is composed of at least one of propane and propylene and difluoroethane, and the mass percentage of difluoroethane in the mixed refrigerant is 65-85%.

3. The mixed refrigerant according to claim 1, characterized in that: The mixed refrigerant is composed of at least one of propane and propylene and ethane; and the mass percentage of ethane in the mixed refrigerant does not exceed 10%, or is 21% to 50%.

4. The mixed refrigerant according to claim 1, characterized in that: The mixed refrigerant consists of three components: ethane, propane and propylene. The mass ratio of ethane, propane and propylene in the mixed refrigerant is 0.1:0.05:0.85, or 0.21:0.64:0.15, or 0.25:0.1:0.65, or 0.25:0.25:0.5, or 0.35:0.05:0.6, or 0.5:0.05:0.

45.

5. The mixed refrigerant according to claim 1, characterized in that: The mixed refrigerant consists of two components, ethane and propylene, and the mass ratio of ethane to propylene in the mixed refrigerant is 0.05:0.95, or 0.1:0.9, or 0.21:0.79, or 0.25:0.75, or 0.3:0.7, or 0.4:0.6, or 0.5:0.

5.

6. The mixed refrigerant according to claim 1, characterized in that: The mixed refrigerant consists of two components, ethane and propane, and the mass ratio of ethane to propane in the mixed refrigerant is 0.21:0.79, or 0.25:0.

75.

7. The mixed refrigerant according to claim 1, characterized in that: The mixed refrigerant consists of three components: propane, propylene and difluoroethane. The mass ratio of propane, propylene and difluoroethane in the mixed refrigerant is 0.05:0.1:0.85, or 0.05:0.3:0.65, or 0.1:0.05:0.85, or 0.3:0.05:0.

65.

8. The mixed refrigerant according to claim 1, characterized in that: The mixed refrigerant is composed of two components, propane and difluoroethane, and the mass ratio of propane to difluoroethane in the mixed refrigerant is 0.2:0.8, or 0.25:0.75, or 0.3:0.7; Alternatively, the mixed refrigerant consists of two components, propylene and difluoroethane, and the mass ratio of propylene to difluoroethane in the mixed refrigerant is 0.2:0.8, or 0.3:0.

7.

9. Use of the mixed refrigerant as claimed in any one of claims 1 to 8 as a refrigerant.

10. The use according to claim 9, characterized in that: The mixed refrigerant is used as a refrigerant for household air conditioners, central air conditioners, heat pump water heaters, cold storage or automotive air conditioners; preferably, the application is to replace R32, R410A or R22 refrigerants.

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