A mixed refrigerant and its use

Abstract

This invention belongs to the field of refrigerant technology and discloses a mixed refrigerant and its application. The mixed refrigerant is composed of two or three of ethane, propane, propylene, and difluoroethane. When ethane is included, its mass percentage in the mixed refrigerant does not exceed 10%, or is between 21% and 50%. When difluoroethane is included, its mass percentage is between 65% and 85%. This invention, by improving the composition and proportion of each component of the mixed refrigerant, solves the technical problems of high GWP values, low energy efficiency, low volumetric refrigeration capacity, and poor refrigeration performance associated with existing refrigerants. It can be used to replace R32 or R290, has a low exhaust temperature, high volumetric refrigeration capacity, and requires less refrigerant charge, and can be used to replace high GWP refrigerants such as R32 and R410A.

Description

Technical Field

[0001] This invention belongs to the field of refrigerant technology, and more specifically, relates to a mixed refrigerant and its application, which is an environmentally friendly mixed refrigerant that can replace R32 or R410A. Background Technology

[0002] As people pay more attention to ozone layer depletion and the worsening 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, making the task of finding high-performance alternative refrigerants all the more urgent.

[0003] In recent years, difluoromethane (R32) has been widely used in the residential air conditioning sector as a transitional alternative to R410A, offering higher volumetric cooling capacity and coefficient of performance (COP) as well as lower gas fluorinated greenhouse gases (GWP). However, according to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR6), the GWP of R32 has been revised to 771, exceeding the limit set by the European Parliament's F-gas Regulation for refrigerants used in residential air conditioning. According to the European Parliament's regulations, after 2025, fluorinated greenhouse gases with a GWP of 750 or higher will be prohibited in split-type air conditioning systems with a charge of less than 3 kg. Therefore, research into alternatives to R32 used in air conditioning is urgently needed.

[0004] Currently, propane (R290), a natural refrigerant, is one of the main approaches to replacing R32 refrigerant. However, air conditioning systems using R290 have excessively low volumetric cooling capacity, requiring further energy efficiency improvements, and their refrigerant charge is strictly limited. Therefore, a new refrigerant is urgently needed to address these issues.

[0005] Professor He Guogeng reported a binary mixed refrigerant constructed using ethane and propylene (see Chinese patent application CN114752357A), in which ethane accounts for 11%–20% by mass and propylene accounts for 89%–80% by mass, capable of replacing R32 and R410a refrigerants. Although this refrigerant can replace R32 to some extent, there is still room for improvement in system energy efficiency, refrigeration capacity per unit volume, and safety (the components of this refrigerant are the same as R290, both being highly flammable refrigerants, thus not improving the safety of pure R290).

[0006] In addition, Professor He Guogeng reported a ternary mixed refrigerant constructed using ethane, propylene, and propane (see Chinese patent application CN114752356A), wherein ethane comprises 12%–20.5%, propylene 75.5%–87%, and propane 1%–4%, which 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 terms of system energy efficiency, refrigeration capacity per unit volume, and safety (the components of this refrigerant are the same as R290, both being highly flammable refrigerants, and it does not improve the safety of pure R290). Summary of the Invention

[0007] To address the aforementioned deficiencies or improvement needs of existing technologies, the present invention aims to provide a mixed refrigerant and its applications. By improving the composition and proportions of the components of the mixed refrigerant, the technical problems of high GWP values, low energy efficiency, low volumetric refrigeration capacity, and impaired refrigeration performance of existing refrigerants can be solved. The refrigerant obtained by this invention is a mixed refrigerant, belonging to the category of energy-saving and environmentally friendly refrigerants. It has high energy efficiency and can be used to replace R32 or R290 (or even directly replace R32 or R290 without replacing refrigeration components). It has a low exhaust temperature, high volumetric refrigeration capacity, and low refrigerant charge. The present invention has an ODP value of 0 and a GWP value below 150, exhibiting significant environmental advantages and 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, and automotive air conditioning.

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

[0009] When the component contains ethane, the mass percentage of ethane in the mixed refrigerant shall not exceed 10%, or be 21% to 50%;

[0010] When the component contains difluoroethane, the mass percentage of difluoroethane in the mixed refrigerant is 65-85%.

[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 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%.

[0013] As a further preferred embodiment of the present invention, the mixed refrigerant is composed 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.

[0014] As a further preferred embodiment of the present invention, the mixed refrigerant is composed of two components, ethane and propylene, wherein 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.

[0015] As a further preferred embodiment of the present invention, the mixed refrigerant is composed of two components, ethane and propane, wherein 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 is composed of three components: propane, propylene, and difluoroethane, wherein 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, wherein 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 may consist of two components: propylene and difluoroethane, wherein 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 application of the above-described mixed refrigerant as a refrigerant working fluid.

[0020] As a further preferred embodiment of the present invention, the mixed refrigerant is used as a refrigerant in household air conditioners, central air conditioners, heat pump water heaters, cold storage refrigeration systems, 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 in this invention can achieve the following results.

[0022] Beneficial effects:

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

[0024] 2. The refrigerant provided by this invention has a higher COP value than R32 and R410A, and has significant advantages in energy saving and emission reduction.

[0025] 3. The present invention particularly preferably comprises a refrigerant composed of at least one of propane and propylene with ethane, wherein the mass percentage of ethane in the mixed refrigerant is no more than 10% or is 21%–50%. These preferred formulations result in refrigerants with operating pressures and volumetric cooling capacities close to those of R32 and R410A, and higher than those of R290. They can be directly used to replace R32 and R410A without requiring extensive component replacement, or only requiring modifications to some components. Furthermore, based on the present invention, a mixed refrigerant composed of at least one of propane and propylene with difluoroethane is also preferred, wherein the mass percentage of difluoroethane in the mixed refrigerant is 65%–85%. These preferred formulations result in refrigerants with operating pressures and volumetric cooling capacities close to those of R290, and can be directly used to replace R290 without requiring extensive component replacement, or only requiring modifications to some components.

[0026] 4. The refrigerant provided by this invention has a lower discharge temperature than R32, which is beneficial to the operation of the refrigeration compressor and makes the refrigeration compressor more reliable.

[0027] 5. The present invention preferably uses a mixed refrigerant composed of at least one of propane and propylene and difluoroethane, wherein the mass percentage of difluoroethane in the mixed refrigerant is 65-85%. The refrigerants obtained by these preferred formulations are less flammable than R290 and the prior art CN114752357A and CN114752356A, thereby improving safety.

[0028] 6. The refrigerant provided by this invention can fill the gap in alternatives to R32 and R410A refrigerants and solve the problems of low volumetric 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 phasing out and replacement of high GWP refrigerants.

[0029] Compared to CN114752357A and CN114752356A, although both belong to environmentally friendly mixed refrigerants that can replace R32 or R410A, this invention overcomes the composition and ratio limitations of these prior art technologies, obtaining more mixed refrigerants that are more beneficial to refrigeration cycle performance. This invention optimizes system energy efficiency, cooling capacity per unit volume, and safety compared to existing technologies. Based on the non-azeotropic mixed refrigerants obtained by this invention, it is possible to further construct refrigeration and air conditioning systems using non-azeotropic mixed refrigerants as the working fluid. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0031] The mixed refrigerant in this 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 name R170 R290 R1270 R152a Molecular formula <![CDATA[C2H6]]> <![CDATA[C3H8]]> <![CDATA[C3H6]]> <![CDATA[C2H4F2]]> relative molecular mass 30.069 44.096 42.08 66.051 Latent heat of vaporization (1 atm) 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 of the prior art, for example including the following steps: mixing gaseous ethane, gaseous propane, gaseous propylene and gaseous difluoroethane in a certain proportion to obtain the mixed refrigerant.

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

[0037] The aforementioned refrigerants are mutually soluble according to the principle of "like dissolves like," and can therefore be physically mixed by being added to the refrigerant tank in descending order of boiling point according to their weight ratio. Alternatively, they can be added to the compressor in descending order of boiling point according to their weight ratio, and then used after thorough mixing.

[0038] The following are specific examples:

[0039] Example 1: Take ethane, propane and propylene refrigerants commonly used in the refrigerant field, and in the liquid phase, take 10% ethane, 5% propane and 85% propylene by mass and mix them thoroughly to obtain a mixed refrigerant.

[0040] Example 2: Take ethane, propane and propylene refrigerants commonly used in the refrigerant field, and in the liquid phase, take 21% ethane, 64% propane and 15% propylene by mass and mix them thoroughly to obtain a mixed refrigerant.

[0041] Example 3: Take ethane, propane and propylene refrigerants commonly used in the refrigerant field, and in the liquid phase, take 25% ethane, 10% propane and 65% propylene by mass and mix them thoroughly to obtain a mixed refrigerant.

[0042] Example 4: Take ethane and propylene, commonly used refrigerants in the refrigerant field, and in the liquid phase, take 5% ethane and 95% propylene by mass and mix them thoroughly to obtain a mixed refrigerant.

[0043] Example 5: Take ethane and propylene, commonly used refrigerants in the refrigerant field, and in the liquid phase, take 25% ethane and 75% propylene by mass and mix them thoroughly to obtain a mixed refrigerant.

[0044] Example 6: Take ethane and propylene, commonly used refrigerants in the refrigerant field, and in the liquid phase, take 50% ethane and 50% propylene by mass and mix them thoroughly to obtain a mixed refrigerant.

[0045] Example 7: Take ethane and propane refrigerants commonly used in the refrigerant field, and in the liquid phase, take 21% ethane and 79% propane by mass and mix them thoroughly to obtain a mixed refrigerant.

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

[0047] Example 9: Propane, propylene and difluoroethane, commonly used refrigerants in the refrigerant field, were taken and, in the liquid phase, 5% propane, 10% propylene and 85% difluoroethane were thoroughly physically mixed to obtain a mixed refrigerant.

[0048] Example 10: Propane, propylene and difluoroethane, commonly used refrigerants in the refrigerant field, were taken and, in the liquid phase, 30% propane, 5% propylene and 65% difluoroethane by mass percentage were thoroughly physically mixed to obtain a mixed refrigerant.

[0049] Example 11: Propane and difluoroethane, commonly used refrigerants in the refrigerant field, were taken and, in the liquid phase, 20% by mass of propane and 80% by mass of difluoroethane were thoroughly physically mixed to obtain a mixed refrigerant.

[0050] Example 12: Propylene and difluoroethane, commonly used refrigerants in the refrigerant field, were taken and, in the liquid phase, 20% by mass of propylene and 80% by mass of difluoroethane were thoroughly physically mixed to obtain a mixed refrigerant.

[0051] Comparative Example 1: Ethane, propane and propylene refrigerants commonly used in the refrigerant field were taken and, in the liquid phase, 80% ethane, 10% propane and 10% propylene by mass were fully physically mixed to obtain a mixed refrigerant.

[0052] Comparative Example 2: Propane, propylene and difluoroethane, commonly used refrigerants in the refrigerant field, were taken and mixed thoroughly in the liquid phase with a mass percentage of 30% propane, 50% propylene and 20% difluoroethane to obtain a mixed refrigerant.

[0053] To compare performance, theoretical cyclic calculations of the air conditioning system were performed using the above embodiments and R32 and R290. The cooling conditions of the air conditioner were taken as follows: evaporation temperature 10℃, condensation temperature 47℃, condenser outlet temperature 38℃, compressor inlet temperature 20℃, and compressor isentropic efficiency 0.8. This invention focuses on optimizing the cooling conditions of the air conditioner. In actual production, air conditioners using non-azeotropic refrigerants as the working fluid may experience problems such as excessively low evaporator inlet temperatures leading to frost formation and affecting performance during winter heating. Therefore, the cyclic calculations also considered the evaporator inlet temperature during heating (too low an evaporator inlet temperature will cause frost formation on the outdoor unit evaporator during heating, which will reduce the actual system energy efficiency). The heating conditions were: evaporation temperature 2℃, condensation temperature 45℃, condenser outlet temperature 35℃, compressor inlet temperature 5℃, and compressor isentropic efficiency 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 1-6

[0055]

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

[0057]

[0058]

[0059] Based on the theoretical calculations for the above working conditions, we can conclude that:

[0060] 1. The refrigerants provided in Examples 1 to 12 of this invention have higher coefficient of performance (COP) than R32 and R290, with the highest COP being 22.2% higher than that of R32, resulting in significant energy-saving and emission-reduction benefits.

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

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

[0063] 4. Under the same operating conditions, the condensing pressure, evaporating pressure, and cooling capacity per unit volume of Examples 1-5 and 7-8 of this invention are similar to those of R32, and their COP is higher than that of R32. Therefore, they are feasible to directly replace R32 and R410A under operating conditions (without replacing system components). The condensing pressure, evaporating pressure, and cooling capacity per unit volume of Examples 9-12 are similar to those of R290, and their COP is higher than that of R290. Therefore, they are feasible to directly replace R290 under operating conditions (without replacing system components). The increased COP means improved energy efficiency.

[0064] 5. All four components used in this invention are environmentally friendly refrigerants, posing no ozone layer hazard and exhibiting extremely low greenhouse effect. The GWP of each of the above embodiments does not exceed 150, meeting the EU F-gas regulations for environmentally friendly refrigerants in household air conditioning. This invention can be widely applied in various fields of refrigeration, especially in household air conditioning, central air conditioning, heat pump water heaters, cold storage, and automotive air conditioning systems.

[0065] 6. Furthermore, based on the present invention, in the embodiments using difluoroethane (e.g., Examples 9 to 12), since difluoroethane is a weakly flammable substance, the flammability of the mixture is reduced, thereby improving safety.

[0066] Those skilled in the art will readily understand that the above description is merely 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 within the scope of protection of the present invention.

Claims

1. A mixed refrigerant, characterized in that, It is composed of three components: propane, propylene, and difluoroethane. The mass percentage of difluoroethane in the mixed refrigerant is 65-85%.

2. The mixed refrigerant as described in claim 1, characterized in that, 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.

3. The application of the mixed refrigerant as described in any one of claims 1-2 as a refrigerant.

4. The application as described in claim 3, characterized in that, The mixed refrigerant is used as a refrigerant in household air conditioners, central air conditioners, heat pump water heaters, cold storage facilities, or automotive air conditioners; the application is to replace R32 and R410A refrigerants.

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