A heat transfer composition and preparation method thereof

Abstract

The present invention discloses a heat transfer composition comprising 15 to 60 parts by weight of trans-1,2-difluoroethylene and 35 to 85 parts by weight of 1,1-difluoroethane. The present invention also discloses a method for preparing the heat transfer composition. The heat transfer composition of the present invention has a global warming potential (GWP) value of less than 150, can replace 1,1,1,2-tetrafluoroethane in a heat transfer system, and has good cooling and heating effects and excellent flame retardancy.

Description

Technical Field

[0001] The present invention relates to the field of refrigeration and heating, and in particular to a heat transfer composition and a preparation method thereof. Background Art

[0002] As ozone depletion and greenhouse gas emissions became increasingly prominent, the international community enacted the Montreal Protocol to phase out chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), and the Kyoto Protocol to limit greenhouse gas emissions. The Montreal Protocol has phased out nearly 99% of ozone-depleting substances (ODS), including those with high global warming potential (GWP), such as CFCs. However, some ODS alternatives, such as hydrofluorocarbons (HFCs), also have high GWP. Since the Montreal and Kyoto Protocols, countries have increasingly stringent requirements for refrigerant replacements. In addition to the basic requirement that new refrigerants be ozone-safe, they are also required to have the lowest possible GWP (global warming potential).

[0003] 1,1,1,2-Tetrafluoroethane (HFC-134a) is non-toxic, non-corrosive, and has an ODP of zero, offering excellent safety and refrigeration performance. It is used to replace traditional HCFC-22 refrigerants in refrigeration applications such as automotive air conditioning, heat pumps, chillers, and refrigerators. However, HFC-134a has a high global warming potential (GWP) of 1430, making it a potent greenhouse gas and a target for regulation under the Kyoto Protocol. Currently, a variety of heat transfer fluids have been developed to replace 1,1,1,2-tetrafluoroethane, with GWPs ranging from below 150 to around 1000. Most of these mixtures are based on 2,3,3,3-tetrafluoropropene (HFO-1234yf), such as 2,3,3,3-tetrafluoropropene, propane, and their combinations. Comparisons have revealed that compositions with GWPs below 150 are more flammable and exhibit poor cooling and heating performance.

[0004] For example, CN101851490A discloses a mixed refrigerant containing 2,3,3,3-tetrafluoropropene (HFO-1234yf), E-1,3,3,3-tetrafluoropropene (E-HFO-1234ze) and 1,1-difluoroethane (HFC-152a). The GWP of the mixed refrigerant is less than 100, and the COP value (energy efficiency ratio) is close to that of HFC-134a. However, the mixed refrigerant has certain flammability and a high content of fluorinated olefins, which leads to a high replacement cost.

[0005] For example, CN110628389A discloses a ternary mixed refrigerant for replacing HFC-134a. The first component is the flame retardant trifluoroiodomethane, the second component is trifluoromethyl methyl ether, and the third component is one of 2,3,3,3-tetrafluoropropene, 3,3,3-trifluoropropene (HFO-1243zf), E-1,3,3,3-tetrafluoropropene, 1,1-difluoroethane, 1,1,1,2-tetrafluoroethane, and 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea). The GWP of the preferred refrigerant is less than 100, but the COP value of all mixed refrigerants is less than that of HFC-134a.

[0006] For example, CN107400502A discloses a ternary mixed refrigerant of difluoromethane, propylene, and trifluoroiodomethane for use in place of HFC-134a. The optimized mixed refrigerant can save up to 12% of energy compared to HFC-134a, but the mixed refrigerant still has a certain flammability risk.

[0007] For example, CN113348222A discloses a composition containing trans-1,2-difluoroethylene (HFO-1132(E)). This composition contains HFO-1132(E) and at least one additional compound. This composition is an azeotropic or azeotrope-like composition and can be used as a heat transfer medium, foaming agent, or propellant. However, a drawback is that the combined content of the additional compounds (including 1,1-difluoroethylene) is less than 10 parts per million, resulting in a COP value lower than that of HFC-134a. This results in low energy efficiency for the refrigeration system, preventing the composition from realizing its energy-saving and environmentally friendly advantages. Summary of the Invention

[0008] The purpose of the present invention is to provide a heat transfer composition with low GWP, high safety and good cooling and heating effects and a preparation method thereof in response to the deficiencies of the prior art.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is: a heat transfer composition, comprising, by weight:

[0010] 15-60 parts of trans-1,2-difluoroethylene (HFO-1132(E))

[0011] 35 to 85 parts of 1,1-difluoroethane.

[0012] Preferably, the heat transfer composition further comprises one of other fluoroalkanes, other fluoroolefins, and alkanes.

[0013] Preferably, the other fluoroalkane is one of monofluoromethane, difluoromethane, pentafluoroethane, 1,1,1,2-tetrafluoroethane and trifluoroiodomethane.

[0014] Preferably, the weight proportion of the other fluoroalkanes is 4-12 parts.

[0015] Preferably, the other fluoroolefin is one of 1,1,2-trifluoroethylene, trans-1,3,3,3-tetrafluoropropene and 2,3,3,3-tetrafluoropropene.

[0016] Preferably, the weight proportion of the other fluoroolefins is 5-15 parts.

[0017] Preferably, the alkane is one of propane and isobutane.

[0018] Preferably, the weight portion of the alkane is 1-5 parts.

[0019] Preferably, the heat transfer composition has a global warming potential (GWP) of less than or equal to 150.

[0020] Preferably, the flammability of the heat transfer composition is less than or equal to A2.

[0021] The present invention also provides a method for preparing the heat transfer composition, which comprises physically mixing the components according to their weight ratio in a liquid phase to obtain the heat transfer composition.

[0022] While the trans-1,2-difluoroethylene described in this invention has excellent environmental performance and a high cooling capacity per unit volume, its cooling and heating cycle efficiency is relatively low. While mixing it with HFCs can improve their cycle efficiency, the GWP of such mixed heat transfer media exceeds 150, failing to meet environmental requirements.

[0023] The 1,1-difluoroethane described in the present invention has a GWP of 124 and offers the advantage of high cooling and heating cycle efficiency. However, its low vapor density results in a relatively low refrigeration capacity per unit volume.

[0024] The other fluoroalkanes or other fluoroolefins or alkanes described in this invention are technically mature heat transfer fluids, but they all have certain limitations. Adding these other fluoroalkanes or other fluoroolefins or alkanes to heat transfer compositions can further optimize the formulation's flammability, GWP, and cooling and heating performance for different applications.

[0025] The thermal composition of the present invention utilizes an optimized formulation, combining the advantages of each component. Through synergistic action, these components minimize adverse factors and exhibit excellent results. This composition simultaneously improves the cooling and heating cycle efficiency of trans-1,2-difluoroethylene and the cooling capacity per unit volume of 1,1-difluoroethane. The novel heat transfer composition of the present invention has a Globally Preservative Value (GWP) of less than 150, and exhibits superior cooling and heating performance and capacity compared to 1,1,1,2-tetrafluoroethane, making it a direct replacement for 1,1,1,2-tetrafluoroethane.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. Good environmental performance. The heat transfer composition of the present invention uses trans-1,2-difluoroethylene as its main component, has an ozone depletion potential (ODP) of 0 and a global warming potential (GWP) of less than 1. It has excellent environmental performance and a superior cooling capacity per unit volume, which can effectively improve the environmental performance of the heat transfer composition. The GWP of the heat transfer composition of the present invention is no more than 150.

[0028] 2. Good refrigeration performance. The thermal composition of the present invention contains trans-1,2-difluoroethylene and 1,1-difluoroethane at the same time. By optimizing the formula, the advantages of trans-1,2-difluoroethylene and 1,1-difluoroethane are combined, and the synergistic effect is achieved. At the same time, the refrigeration and heating cycle efficiency of trans-1,2-difluoroethylene is improved, and the unit volume refrigeration capacity of 1,1-difluoroethane is also increased. The refrigeration (heating) coefficient and unit volume refrigeration (heating) capacity of the heat transfer composition of the present invention are better than those of single working fluids 1,1,1,2-tetrafluoroethane and 2,3,3,3-tetrafluoropropylene, and can directly replace 1,1,1,2-tetrafluoroethane.

[0029] 3. Good safety performance. The thermal composition of the present invention combines the advantages of each component through optimized formula. Through the synergistic effect of each component, it has good flame retardancy. The flammability of the heat transfer composition is not greater than A2. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a temperature-pressure comparison chart of the heat transfer composition in Example 1 of the present invention and 1,1,1,2-tetrafluoroethane. DETAILED DESCRIPTION

[0031] The present invention is further described below with reference to specific embodiments, but the present invention is not limited to the embodiments.

[0032] Example 1

[0033] The following components were physically mixed in liquid phase according to their weight proportions to obtain a heat transfer composition. The mass ratio of the materials was: 25% trans-1,2-difluoroethylene and 75% 1,1-difluoroethane. The properties of the heat transfer composition are shown in Table 1.

[0034] Example 2

[0035] The following components were physically mixed in liquid phase according to their weight proportions to obtain a heat transfer composition. The mass ratio of the materials was: 50% trans-1,2-difluoroethylene and 50% 1,1-difluoroethane. The properties of the heat transfer composition are shown in Table 1.

[0036] Example 3

[0037] The following components were physically mixed in a liquid phase according to their weight proportions to produce a heat transfer composition. The mass ratio of the materials was: 43% trans-1,2-difluoroethylene, 45% 1,1-difluoroethane, and 12% iodotrifluoromethane. The properties of the heat transfer composition are shown in Table 1.

[0038] Example 4

[0039] The following components were physically mixed in a liquid phase according to their weight proportions to produce a heat transfer composition. The mass ratio of the materials was: 35% trans-1,2-difluoroethylene, 60% 1,1-difluoroethane, and 5% trans-1,3,3,3-tetrafluoropropylene. The properties of the heat transfer composition are shown in Table 1.

[0040] Example 5

[0041] The following components were physically mixed in a liquid phase according to their weight proportions to produce a heat transfer composition. The mass ratio of the materials was: 35% trans-1,2-difluoroethylene, 50% 1,1-difluoroethane, and 15% 2,3,3,3-tetrafluoropropylene. The properties of the heat transfer composition are shown in Table 1.

[0042] Example 6

[0043] The following components were physically mixed in a liquid phase according to their weight proportions to produce a heat transfer composition. The mass ratio of the materials was: 20% trans-1,2-difluoroethylene, 65% 1,1-difluoroethane, and 15% 1,1,2-trifluoroethylene. The properties of the heat transfer composition are shown in Table 1.

[0044] Example 7

[0045] The following components were physically mixed in a liquid phase according to their weight proportions to produce a heat transfer composition. The mass ratio of the materials was: 34% trans-1,2-difluoroethylene, 62% 1,1-difluoroethane, and 4% difluoromethane. The properties of the heat transfer composition are shown in Table 1.

[0046] Example 8

[0047] The following components were physically mixed in a liquid phase according to their weight proportions to produce a heat transfer composition. The mass ratio of the materials was: 56% trans-1,2-difluoroethylene, 41% 1,1-difluoroethane, and 3% propane. The properties of the heat transfer composition are shown in Table 1.

[0048] Example 9

[0049] The following components were physically mixed in a liquid phase according to their weight proportions to produce a heat transfer composition. The mass ratio of the materials was: 48% trans-1,2-difluoroethylene, 46% 1,1-difluoroethane, and 6% 1,1,1,2-tetrafluoroethane. The properties of the heat transfer composition are shown in Table 1.

[0050] Table 1 Comparison of thermal parameters and thermal performance under air-conditioning conditions

[0051]

[0052]

[0053] Flammability testing first involves conducting flammability tests on each refrigerant mixture according to the US ASTM-E681-04 standard to determine whether the refrigerant is flammable. For flammable refrigerants, the maximum burning rate of each mixture is evaluated by calculating the fluorine substitution ratio and maximum adiabatic flame temperature for each example. The safety classification of each refrigerant mixture is then determined according to GB / T7778-2017.

[0054] Table 1 compares the thermal parameters (i.e., average boiling point, flammability, GWP value, cooling (heating) capacity per unit volume) and thermodynamic performance (Coefficient of Refrigeration (COPc) and Coefficient of Heating (COPh)) of the heat transfer compositions prepared in Examples 1 to 9 above with those of 1,1,1,2-tetrafluoroethane, 2,3,3,3-tetrafluoropropylene, propane, R513A, and R454C under air-conditioning conditions (evaporating temperature 5°C, condensing temperature 45°C, superheat 10K, subcooling 5K).

[0055] As can be seen from Table 1, under air conditioning conditions, the heat transfer compositions prepared in Examples 1-9 exhibit low GWP. Their cooling (heating) coefficients and cooling (heating) capacity per unit volume are superior to those of single refrigerants such as 1,1,1,2-tetrafluoroethane and 2,3,3,3-tetrafluoropropylene. Furthermore, the cooling (heating) coefficients and GWP values of the heat transfer compositions prepared in Examples 1-9 are superior to those of existing compositions such as R513A and R454C.

Claims

1. A heat transfer composition, characterized in that The materials are mixed in the following proportions by mass: 20% trans-1,2-difluoroethylene, 65% 1,1-difluoroethane, and 15% 1,1,2-trifluoroethylene.

2. The heat transfer composition according to claim 1, characterized in that The heat transfer composition has a global warming potential of less than or equal to 150.

3. The heat transfer composition according to claim 1, wherein The flammability of the heat transfer composition is less than or equal to A2.

4. The method for preparing the heat transfer composition according to any one of claims 1 to 3, characterized in that: The components are physically mixed in a liquid state according to their weight ratio to obtain the heat transfer composition.

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