A refrigerant composition and use thereof

Abstract

The present application relates to the technical field of low GWP refrigerant, in particular to a refrigerant composition and its use. The composition comprises a refrigerant blend, which consists of 65wt% to 88wt% of HFO-1234ze(E), 12wt% to 32wt% of CO2, 0wt% to 10wt% of HFO-1243zf, and 0.01wt% to 0.1wt% of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid based on the refrigerant blend. The average temperature glide of the refrigerant composition is less than 2K. The composition has low GWP, good thermal performance, low environmental burden and adjustable flammability, and is suitable for vehicle thermal management and fixed refrigeration / air conditioning / heat pump systems. The present application also provides its use.

Description

Technical Field

[0001] This invention relates to the field of low-GWP refrigerant technology, and more specifically to a refrigerant composition and its use. Background Technology

[0002] As the automotive industry accelerates its transition to electrification, the widespread adoption of hybrid, plug-in hybrid, and all-electric vehicles has significantly reduced or even eliminated the heat source role of the internal combustion engine (ICE). Traditional methods of heating the passenger compartment using engine waste heat are no longer suitable. While existing technologies can employ auxiliary heating methods such as PTC heaters, their energy utilization efficiency is relatively low, making it difficult to meet the demands of electrified vehicles for efficient thermal management.

[0003] Meanwhile, as environmental regulations increasingly restrict the global warming potential (GWP) of refrigerants, traditional high-GWP refrigerants are gradually being replaced, and low-GWP refrigerants have become an important development direction in this field. Existing technologies such as CN102965082A and CN108753258A all involve low-GWP refrigerant compositions or related application schemes, indicating that the field has attempted to replace traditional refrigerants by optimizing refrigerant components and ratios. However, existing low-GWP refrigerants still have shortcomings in low-temperature heating performance, temperature glide control, system energy efficiency, and compatibility with system materials and lubricants, making it difficult to simultaneously achieve environmental friendliness, safety, and overall performance.

[0004] Therefore, in response to the demand for efficient, stable, and low-environmental-load thermal management media in electrified vehicles and stationary refrigeration, air conditioning, and heat pump equipment, it is still necessary to develop a new refrigerant composition that combines low GWP, high energy efficiency, low temperature glide, and good system compatibility. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a refrigerant composition that overcomes the deficiencies of existing low-GWP refrigerants in terms of refrigeration capacity, low-temperature heating performance, flammability, and environmentally persistent degradation products; the present invention also provides its uses.

[0006] The objective of this invention is achieved through the following technical solution: The refrigerant composition of the present invention is mainly based on HFO-1234ze(E), and includes HFO-1234ze(E), CO2, optional HFO-1243zf and trace amounts of [BMIM][PF6] ionic liquid.

[0007] Specifically, the refrigerant composition of the present invention comprises a refrigerant blend, said refrigerant blend being composed of the following components: 65wt% to 88wt% HFO-1234ze(E); 12wt% to 32wt% CO2; 0wt% to 10wt% HFO-1243zf; The total amount of the refrigerant blend is 100 wt%; The refrigerant composition further comprises 0.01 wt% to 0.1 wt% of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid ([BMIM][PF6] ionic liquid) based on the refrigerant blend. The average temperature slip of the refrigerant composition is less than 2K.

[0008] The GWP of the refrigerant composition is less than or equal to 2.

[0009] Preferably, the HFO-1243zf content in the refrigerant blend is 2 wt% to 8 wt%. In this case, the refrigerant composition provides an average temperature glide of 0.1 K to 1.6 K.

[0010] The refrigerant composition of the present invention may further include one or more additives to further improve its performance and stability in actual systems.

[0011] The preferred solution is as follows: The refrigerant composition further comprises a lubricant having a kinematic viscosity of 20 cSt to 500 cSt at 40°C and a volume resistivity greater than 10 at 20°C. 12 The lubricant is selected from Ω·m to ensure adequate lubrication of the compressor and maintain good electrical insulation properties. Preferably, the lubricant is one or more of polyalkylene glycol (PAG), polyol ester (POE), poly-α-olefin (PAO), and polyvinyl ether (PVE). Its dosage is from 0.1 wt% to 5 wt% based on the refrigerant blend.

[0012] The refrigerant composition further comprises a stabilizer, which is one or more of toluenetriazole, benzotriazole, tert-butylhydroquinone, d-limonene, n-butyl glycidyl ether, and butylated hydroxytoluene, and the amount of the stabilizer is 0.1 wt% based on the refrigerant blend to inhibit the polymerization or oxidative decomposition of the olefin component.

[0013] The refrigerant composition further comprises 50 ppm by weight of a tracer, where 50 ppm is based on the amount used in the refrigerant blend. The tracer is one or more of HFC-134a, HFO-1234yf, HCFC-22, and HFC-143a, to facilitate leak detection and system maintenance.

[0014] The degradation products of the refrigerant composition contain less than 0.5 mg / g of trifluoroacetic acid (TFA) in the refrigerant composition. This is significantly lower than that of existing HFO refrigerants, thereby further reducing environmental risks.

[0015] The method for preparing the composition of the present invention may include the following steps: Under vacuum conditions, HFO-1234ze(E), CO2, and optional HFO-1243zf are added to a sealed container in a preset ratio and stirred at room temperature (20-25℃) for 30-60 minutes to make it initially uniform; then [BMIM][PF6] ionic liquid and other additives are added, and stirring is continued for 30-60 minutes until completely mixed, which yields the final product.

[0016] The refrigerant composition of the present invention is used as a heat transfer fluid in heating and cooling hybrid vehicles, electric vehicles, or stationary refrigeration / air conditioning / heat pump systems.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Excellent environmental friendliness: GWP≤2, far lower than HFC-134a and HFO-1234yf; the content of trifluoroacetic acid (TFA) in the degradation products is extremely low, and the ODP is zero.

[0018] (2) Significantly improved thermal performance: The volumetric heat capacity is 18%~29% higher than that of HFC-134a and more than 23% higher than that of HFO-1234yf.

[0019] (3) Safe and controllable flammability: Through the synergistic effect of CO2 and ionic liquid, it can achieve A1 level non-flammable (burning rate is 0) or 2L weakly flammable level, which is safer than existing low GWP refrigerants.

[0020] (4) Excellent system operating characteristics: the average temperature slip is less than 2K (as low as 1.1K), which improves the efficiency of the heat exchanger; the COP is higher than that of HFO-1234yf, and the COP can reach more than 2.5 in the heat pump system of electric vehicles.

[0021] (5) Good compatibility and wide temperature range applicability: It has good compatibility with existing compressors, pipelines, lubricants and sealing materials, and can be applied to vehicle and stationary equipment thermal management systems.

[0022] (6) Wide range of applications: It is suitable for electric vehicle heat pump systems (without PTC), hybrid / internal combustion engine vehicle air conditioning, stationary refrigeration equipment (such as supermarket refrigerators), residential heat pumps, etc., and has a broad market prospect. Detailed Implementation

[0023] The present invention will be further described below with reference to the embodiments, but these embodiments do not limit the implementation of the present invention.

[0024] Unless otherwise specified, the raw materials used in the examples and comparative examples are all commercially available materials, and the process methods used in the examples and comparative examples are all conventional methods in the art.

[0025] 1-Butyl-3-methylimidazolium hexafluorophosphate ionic liquid: [BMIM][PF6] ionic liquid.

[0026] In the following examples and comparative examples, the refrigerant blend was prepared by mixing for 45 minutes before adding 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid; and by mixing for 45 minutes after adding 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid and additives.

[0027] In the examples and comparative examples, the contents of the 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid and the additives are based on the contents of the refrigerant blend.

[0028] Example 1 A refrigerant blend was prepared by mixing HFO-1234ze(E): 73wt%, CO2: 20wt%, and HFO-1243zf: 7wt%. Based on the refrigerant blend, 0.08wt% of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid was added; a polyalkylene glycol (PAG) lubricant (kinematic viscosity 50 cSt at 40℃, volume resistivity greater than 10 Ω·cm at 20℃) was also added. 12 The refrigerant content was 5 wt% based on the refrigerant blend (Ω·m); tert-butylhydroquinone stabilizer was added at a content of 0.1 wt%; and HFO-1234yf tracer was added at a content of 50 ppm.

[0029] The performance results of Example 1, HFO-1234ze(E), HFC-134a, and HFO-1234yf are shown in Table 1.

[0030] Table 1 Performance Indicators

[0031] Note: N / A indicates that Class A1 has no lower limit of flammability (no flame propagation).

[0032] The composition of Example 1 has a GWP of only 2, extremely low TFA formation (<0.5 mg / g), a volumetric heat capacity 29% higher than HFC-134a, and achieves A1 flammability (burning rate of 0). The unique synergistic effect of HFO-1234ze(E), HFO-1243zf, and [BMIM][PF6] results in almost no TFA formation, a significantly higher volumetric heat capacity than HFC-134a, and A1 non-flammability, demonstrating excellent overall performance.

[0033] Example 2 A refrigerant blend was prepared by mixing HFO-1234ze(E): 79 wt%, CO2: 15 wt%, and HFO-1243zf: 6 wt%. Based on the refrigerant blend, 0.01 wt% of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid was added; a polyalkylene glycol (PAG) lubricant (kinematic viscosity 50 cSt at 40°C, volume resistivity greater than 10 Ω·cm at 20°C) was also added. 12 The content of 5 wt% (Ω·m) was added; tert-butylhydroquinone stabilizer was added at a content of 0.1 wt%; and HFO-1234yf tracer was added at a content of 50 ppm.

[0034] The performance results of Example 2, HFO-1234ze(E), HFC-134a, and HFO-1234yf are shown in Table 2.

[0035] Table 2 Performance Indicators

[0036] The composition of Example 2 has a GWP of 1.8. The trifluoroacetic acid (TFA) content in the degradation products of the composition is less than 0.5 mg / g of the refrigerant composition. The volumetric heat capacity is 27% higher than that of HFC-134a, and the flammability reaches A1 level (burning rate of 0). The unique synergistic effect of HFO-1234ze(E), HFO-1243zf, and [BMIM][PF6] significantly improves the heat capacity and inhibits TFA formation, achieving A1 non-flammability and exhibiting excellent overall performance.

[0037] Example 3 A refrigerant blend was prepared by mixing HFO-1234ze(E): 74wt%, CO2: 18wt%, and HFO-1243zf: 8wt%. Based on the refrigerant blend, 0.01wt% of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid was added; a polyalkylene glycol (PAG) lubricant (kinematic viscosity 50 cSt at 40°C, volume resistivity greater than 10 Ω·cm at 20°C) was also added. 12 The content of 5 wt% (Ω·m) was added; tert-butylhydroquinone stabilizer was added at a content of 0.1 wt%; and HFO-1234yf tracer was added at a content of 50 ppm.

[0038] The performance results of Example 3, HFO-1234ze(E), HFC-134a, and HFO-1234yf are shown in Table 3.

[0039] Table 3 Performance Indicators

[0040] The composition of Example 3 has a GWP of 2, the content of trifluoroacetic acid (TFA) in the degradation products of the composition is less than 0.5 mg / g of the refrigerant composition, the volumetric heat capacity is 23% higher than that of HFC-134a, and the flammability reaches A1 level (burning rate is 0).

[0041] Example 4 A refrigerant blend was prepared by mixing HFO-1234ze(E): 66wt%, CO2: 25wt%, and HFO-1243zf: 9wt%. Based on the refrigerant blend, 0.03wt% of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid was added; a polyalkylene glycol (PAG) lubricant (kinematic viscosity 50 cSt at 40℃, volume resistivity greater than 10 Ω·cm at 20℃) was also added. 12 The content of 5 wt% (Ω·m) was added; tert-butylhydroquinone stabilizer was added at a content of 0.1 wt%; and HFO-1234yf tracer was added at a content of 50 ppm.

[0042] The performance results of Example 4, HFO-1234ze(E), HFC-134a, and HFO-1234yf are shown in Table 4.

[0043] Table 4 Performance Indicators

[0044] The composition of Example 4 has a GWP of 2, and the trifluoroacetic acid (TFA) content in the degradation products of the composition is less than 0.5 mg / g of the refrigerant composition. Its volumetric heat capacity is 18% higher than that of HFC-134a, and its flammability reaches A1 level (burning rate of 0). The synergistic effect enables the composition to exhibit superior thermal management performance under the test conditions while maintaining a low TFA level.

[0045] Example 5 A refrigerant blend was prepared by mixing HFO-1234ze(E): 83wt%, CO2: 13wt%, and HFO-1243zf: 4wt%. Based on the refrigerant blend, 0.03wt% of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid was added; a polyalkylene glycol (PAG) lubricant (kinematic viscosity 50 cSt at 40℃, volume resistivity greater than 10 Ω·cm at 20℃) was also added. 12 The content of 5 wt% (Ω·m) was added; tert-butylhydroquinone stabilizer was added at a content of 0.1 wt%; and HFO-1234yf tracer was added at a content of 50 ppm.

[0046] The performance results of Example 5, HFO-1234ze(E), HFC-134a, and HFO-1234yf are shown in Table 5.

[0047] Table 5 Performance Indicators

[0048] The composition of Example 5 has a GWP of 1.7, and the trifluoroacetic acid (TFA) content in the degradation products of the composition is less than 0.5 mg / g of the refrigerant composition. Its volumetric heat capacity is 22% higher than that of HFC-134a, and its flammability is rated at 2L. The synergistic effect results in outstanding low-temperature heating performance while maintaining extremely low TFA levels.

[0049] Example 6 A refrigerant blend was prepared by mixing HFO-1234ze(E): 84 wt%, CO2: 12 wt%, and HFO-1243zf: 4 wt%. Based on the refrigerant blend, 0.03 wt% of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid was added; a polyalkylene glycol (PAG) lubricant (kinematic viscosity 50 cSt at 40°C, volume resistivity greater than 10 Ω·cm at 20°C) was also added. 12 The content of 5 wt% (Ω·m) was added; tert-butylhydroquinone stabilizer was added at a content of 0.1 wt%; and HFO-1234yf tracer was added at a content of 50 ppm.

[0050] The performance results of Examples 6, HFO-1234ze(E), HFC-134a, and HFO-1234yf are shown in Table 6.

[0051] Table 6 Performance Indicators

[0052] The composition of Example 6 has a GWP of 1.6, and the trifluoroacetic acid (TFA) content in the degradation products of the composition is less than 0.5 mg / g of the refrigerant composition. Its volumetric heat capacity is 23% higher than that of HFC-134a, and its flammability is rated at 2L. The synergistic effect significantly improves high-temperature cooling capacity and thermal efficiency while maintaining extremely low TFA levels.

[0053] Example 7 A refrigerant blend was prepared by mixing HFO-1234ze(E): 80wt%, CO2: 15wt%, and HFO-1243zf: 5wt%. Based on the refrigerant blend, 0.05wt% of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid was added; a polyalkylene glycol (PAG) lubricant (kinematic viscosity 50 cSt at 40°C, volume resistivity greater than 10 Ω·cm at 20°C) was also added. 12 The content of 5 wt% (Ω·m) was added; tert-butylhydroquinone stabilizer was added at a content of 0.1 wt%; and HFO-1234yf tracer was added at a content of 50 ppm.

[0054] The performance results of Examples 7, HFO-1234ze(E), HFC-134a, and HFO-1234yf are shown in Table 7.

[0055] Table 7 Performance Indicators

[0056] The composition of Example 7 has a GWP of 1.7, and the trifluoroacetic acid (TFA) content in the degradation products of the composition is less than 0.5 mg / g of the refrigerant composition. It has a volumetric heat capacity 22% higher than HFC-134a and a flammability rating of 2L. A synergistic effect further reduces the slip to 1.1 K while maintaining high heat capacity and extremely low TFA.

[0057] Example 8 A refrigerant blend (total 100 wt%) was prepared by mixing HFO-1234ze(E): 65 wt%, CO2: 32 wt%, and HFO-1243zf: 3 wt%. Based on the refrigerant blend, 0.05 wt% of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid was added; a polyalkylene glycol (PAG) lubricant (kinematic viscosity 50 cSt at 40°C, volume resistivity greater than 10 Ω·cm at 20°C) was also added. 12 The refrigerant content was 5 wt% based on the refrigerant blend (Ω·m); tert-butylhydroquinone stabilizer was added at a content of 0.1 wt%; and HFO-1234yf tracer was added at a content of 50 ppm.

[0058] The performance results of Examples 8, HFO-1234ze(E), HFC-134a, and HFO-1234yf are shown in Table 8.

[0059] Table 8 Performance Indicators

[0060] The composition of Example 8 has a GWP of 2, a TFA content of 0.24 mg / g of refrigerant composition, a volumetric heat capacity 26% higher than HFC-134a, and an A1 flammability rating. The synergistic effect achieves excellent properties of low GWP, high heat capacity, and TFA suppression.

[0061] Example 9 A refrigerant blend (total 100 wt%) was prepared by mixing HFO-1234ze(E): 68 wt% and CO2: 32 wt%. Based on the refrigerant blend, 0.05 wt% of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid was added; a polyalkylene glycol (PAG) lubricant (kinematic viscosity 50 cSt at 40°C, volume resistivity greater than 10 Ω·cm at 20°C) was added. 12The refrigerant content was 5 wt% based on the refrigerant blend (Ω·m); tert-butylhydroquinone stabilizer was added at a content of 0.1 wt%; and HFO-1234yf tracer was added at a content of 50 ppm.

[0062] The performance results of Examples 9, HFO-1234ze(E), HFC-134a, and HFO-1234yf are shown in Table 9.

[0063] Table 9 Performance Indicators

[0064] The composition of Example 9 has a GWP of 2, a TFA content of 0.22 mg / g refrigerant composition, a volumetric heat capacity 28% higher than HFC-134a, and an A1 flammability rating. The synergistic effect achieves excellent properties of low GWP, high heat capacity, and TFA suppression.

[0065] The tests in Examples 1-9 above were based on the SAE automotive heat pump system characterization standards and ANSI / ASHRAE Standard 34 for flammability and toxicity classification. All compositions had a GWP ≤ 2, and the trifluoroacetic acid (TFA) content in the degradation products of these compositions was less than 0.5 mg / g of the refrigerant composition. Their volumetric heat capacity was significantly higher than that of HFC-134a. Examples 1-4 achieved A1 non-flammability through the synergistic effect of CO2 and [BMIM][PF6], fully demonstrating the unique technical effects of this invention.

[0066] Comparative Example 1 A refrigerant blend was prepared by mixing HFO-1234ze(E): 85wt%, CO2: 8wt%, and HFO-1243zf: 7wt%. The same additives as in Example 1 were added to the refrigerant blend. Test results: The average temperature glide increased to 2.8K, the low-temperature heating capacity was insufficient, and the overall thermal performance was significantly worse than that of Example 1.

[0067] Comparative Example 2 A refrigerant blend was prepared by mixing HFO-1234ze(E): 61wt%, CO2: 35wt%, and HFO-1243zf: 4wt%. The same additives as in Example 1 were added to the refrigerant blend. Test results: The system pressure was too high, compatibility decreased, and the temperature glide increased to 3.1K.

[0068] Comparative Example 3 A refrigerant blend was prepared by mixing HFO-1234ze(E): 73 wt%, CO2: 20 wt%, and HFO-1243zf: 7 wt%. The same additives as in Example 1 were added to the refrigerant blend, but without the addition of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid. Test results showed that the composition was inferior to Example 1 in terms of degradation stability and flammability control.

[0069] Comparative Example 4 A refrigerant blend was prepared by mixing HFO-1234ze(E): 73 wt%, CO2: 20 wt%, and HFO-1243zf: 7 wt%. The same additives as in Example 1 were added to the refrigerant blend; however, the amount of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid was adjusted to 0.2 wt%. Test results showed an abnormally high viscosity and a decreased heat exchange efficiency.

[0070] Comparative Example 5 A refrigerant blend was prepared by mixing HFO-1234ze(E): 70wt%, CO2: 18wt%, and HFO-1243zf: 12wt%. The same additives as in Example 1 were added to the refrigerant blend. Test results: The average temperature glide increased to 2.7K, and stability decreased.

[0071] The performance results of Example 1 and Comparative Examples 1-5 are shown in Table 10.

[0072] Table 10 Performance Indicators

[0073] System Application Examples The thermal management system of an electric vehicle consists of an evaporator, compressor, condenser, expansion unit, and reheater, all circulating within the system. In cooling mode, the condenser releases heat, and the evaporator cools the air entering the passenger compartment. In heating mode, a four-way valve switches the refrigerant flow, the evaporator absorbs ambient heat, and the condenser releases heat to the passenger compartment. The reheater dehumidifies while maintaining the cabin temperature. Excess heat can be used for battery thermal management via a battery heat exchanger.

[0074] When using Embodiment 1 or 2, the system exhibits excellent safety and thermal management performance, making it suitable for electric vehicles, hybrid vehicles, and stationary refrigeration / air conditioning / heat pump systems.

[0075] The application of supermarket refrigerated display cases is similar to that of residential heat pump systems. The composition of this invention is highly compatible with existing systems and can be used to replace existing low-GWP refrigerants. The system operates stably and has a long service life.

Claims

1. A refrigerant composition, characterized in that, The refrigerant blend comprises the following components: 65wt% to 88wt% HFO-1234ze(E); 12wt% to 32wt% CO2; 2wt% to 8wt% HFO-1243zf; The total amount of the refrigerant blend is 100 wt%; The refrigerant composition further comprises 0.01 wt% to 0.1 wt% of a 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid based on the refrigerant blend; The average temperature slip of the refrigerant composition is less than 2K; The content of trifluoroacetic acid in the degradation products of the refrigerant composition is less than 0.5 mg / g of the refrigerant composition; The GWP of the refrigerant composition is less than or equal to 2.

2. The refrigerant composition according to claim 1, characterized in that, It also contains a lubricant having a kinematic viscosity of 20 cSt to 500 cSt at 40°C and a volume resistivity greater than 10 at 20°C. 12 Ω·m.

3. The refrigerant composition according to claim 2, characterized in that, The lubricant is one or more of polyalkylene glycol, polyol ester, poly-α-olefin, and polyvinyl ether, and its amount is 0.1 wt% to 5 wt% based on the refrigerant blend.

4. The refrigerant composition according to claim 1, characterized in that, It also contains a stabilizer, which is one or more of toluenetriazole, benzotriazole, tert-butylhydroquinone, d-limonene, n-butyl glycidyl ether, and butylated hydroxytoluene, and the amount of the stabilizer is 0.1 wt% based on the refrigerant blend.

5. The refrigerant composition according to claim 1, characterized in that, It also contains 50 ppm of tracer by weight, which is based on the amount used in the refrigerant blend.

6. The refrigerant composition according to claim 5, characterized in that, The tracer is one or more of HFC-134a, HFO-1234yf, HCFC-22, and HFC-143a.

7. Use of a refrigerant composition according to any one of claims 1-6, characterized in that, Used as a heat transfer fluid for heating and cooling hybrid vehicles, electric vehicles, or stationary refrigeration / air conditioning / heat pump systems.

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