Environment-friendly azeotropic mixed refrigerant formula and preparation process thereof

Abstract

The application relates to the technical field of refrigerant preparation, and discloses an environmentally-friendly azeotropic mixed refrigerant formula and a preparation process thereof, wherein through the optimization design of HFOs double-component matching plus low-proportion HCs, the problems of high GWP of an existing azeotropic refrigerant, contradiction between thermal performance and environmental protection, and combustible risk are solved, phase change temperature drift is only 0.2 DEG C, no component separation occurs in the system operation with load fluctuation and small pressure change, no emptying and re-charging are needed after leakage, only the same type of refrigerant needs to be supplemented, maintenance cost is reduced, no corrosive impurities such as hydrogen fluoride and acidic substances are generated, pipeline corrosion is avoided, in the refrigerant preparation process, low-temperature operation is adopted, inert gas protection is matched, and oxygen content is monitored in real time, the explosion risk of R1270 and the decomposition of HFOs are eliminated, the safety requirements of commercial production are adapted, and ceramic membrane filter elements are adopted for filtration, so that trace solid particles can be effectively filtered to avoid affecting the subsequent mixing effect.

Description

Technical Field

[0001] This invention relates to the field of refrigerant preparation, specifically to an environmentally friendly azeotropic refrigerant formulation and its preparation process. Background Technology

[0002] Azeotropic refrigerants are azeotropic mixtures made by mixing two or more different refrigerants in a certain proportion. During the vaporization or liquefaction process under constant pressure, the vapor composition and solution composition do not change, and the corresponding temperature does not change. There is no component separation during evaporation or condensation, and the thermodynamic properties are stable. Even if there is a leak or maintenance and recharging, the composition will not change, and the remaining refrigerant can continue to be used, reducing resource waste. They are widely used in refrigeration and heat exchange equipment such as refrigerators, air conditioners, cold storage, and heat pumps.

[0003] Currently, the refrigerants used in commercial refrigeration appliances mainly include HFC-based mixed refrigerants (such as R410A), R1234ze(E), and some HCs (hydrocarbon)-based mixed refrigerants. Among them, some refrigerants contain chlorine components that can easily corrode pipelines and affect the service life of equipment; or they have large phase change temperature drift, which can easily lead to component segregation after leakage, resulting in a significant decrease in refrigeration performance, requiring purging and recharging, which is costly; or they pose a risk of combustion and explosion and have insufficient compatibility with commercial lubricants, resulting in significant shortcomings in terms of environmental protection, safety, and thermodynamic performance.

[0004] Furthermore, the existing preparation processes for azeotropic refrigerants mostly follow the traditional dynamic stirring and mixing method or simple static mixing method. The pretreatment, purification, and filling processes are scattered and have a low degree of intelligence, making it difficult to meet the preparation requirements of mixed refrigerants. Moreover, they cannot meet the commercial refrigeration requirements for high precision, high purity, low loss, and large-scale production of refrigerants. Summary of the Invention

[0005] This invention provides an environmentally friendly azeotropic refrigerant formulation and its preparation process to solve the above-mentioned problems.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] An environmentally friendly azeotropic refrigerant formulation, comprising: R1234ze(E), R1234yf, and R1270; the specific molar ratio is: R1234ze(E) is 68-72%, R1234yf is 13-17%, and R1270 is 13-17%.

[0008] Furthermore, R1234ze(E) is 70%, R1234yf is 15%, and R1270 is 15%.

[0009] Furthermore, R1234ze(E) is 72%, R1234yf is 14%, and R1270 is 14%.

[0010] Furthermore, R1234ze (E) is 68%, R1234yf is 13%, and R1270 is 13%.

[0011] An environmentally friendly azeotropic refrigerant preparation process, the preparation process comprising the following steps:

[0012] S1, Pretreatment: Dehydration, degassing, impurity removal, distillation and protection treatment of R1234ze(E), R1234yf and R1270;

[0013] S2, Material Mixing: The raw materials are mixed using a combination of graded metering and low-temperature, high-pressure static mixing.

[0014] S3, Finished Product Purification and Testing: The mixed and matured materials are further purified through a two-stage precision purification system to improve their purity, and are tested batch by batch.

[0015] Furthermore, step S1 specifically includes the following steps:

[0016] S11, Dehydration treatment: A molecular sieve adsorption tower is used. The raw material passes through the adsorption tower at a flow rate of 0.5 m / s. The working temperature of the molecular sieve is 5~8℃ and the pressure is 0.8MPa. The moisture content of the raw material is reduced to <2ppm to avoid HFOs hydrolysis and ice blockage during subsequent mixing.

[0017] S12, Degassing and Impurity Removal: A vacuum degassing tower is used to remove inert gases from the raw materials, reducing the oxygen content to <5ppm, eliminating the risk of combustion and explosion of R1270 and the oxidative decomposition of HFOs;

[0018] S13, Precision Distillation: The raw material is passed through a packed precision distillation column with a reflux ratio controlled at 15:1, a bottom temperature of 20~25℃, and a top temperature of -20~-15℃ to remove particulate impurities and improve the purity of the raw material to ≥99.99%.

[0019] S14, Inert gas protection: High-purity inert gas is introduced into the mixing system during the pretreatment process, and the system is kept at a slight positive pressure to prevent air from seeping in.

[0020] Furthermore, the mixing system includes a high-precision metering tank group, a mass flow meter, a static mixer, a mixing buffer tank, and a low-temperature chiller unit.

[0021] Furthermore, step S2 specifically includes the following steps:

[0022] S21, Pre-cooling and inert gas replacement: Turn on the low-temperature chiller unit to lower the temperature of the metering tank group, static mixer and mixing buffer tank to 5~8℃, and repeatedly fill the mixing system with high-purity inert gas for replacement 3-5 times. After each replacement, evacuate to -0.095MPa to ensure that the oxygen content of the system is <5ppm and the inert gas protection pressure is maintained at 0.15MPa.

[0023] S22, Two-component premixing: R1234ze(E) and R1234yf are fed synchronously in a molar ratio of 70:15 through a closed-loop control of a mass flow meter. The feed rate ratio of the two components is the same as the molar ratio. They are then fed into a static mixer for primary mixing.

[0024] After primary mixing, the material enters the front section of the buffer tank and stays for 30-45 minutes to complete the initial compatibility of HFOs components. During the process, the temperature of the premixed material is maintained at 5~8℃ and the pressure is 1.0MPa.

[0025] S23, Secondary mixing: The premixed materials are mixed in a molar ratio of 85:15, and R1270 is precisely fed into the static mixer through a mass flow meter at the same speed ratio as the molar ratio for secondary mixing.

[0026] During secondary mixing, the pressure inside the static mixer is controlled at 1.2 MPa, the temperature at 6~8℃, and the residence time of the material in the mixer is ≥20s. Molecular-level uniform mixing is achieved through the secondary mixing unit, with no local concentration deviation.

[0027] S24, Post-mixing maturation and stabilization: After secondary mixing, the material enters the mixing buffer tank and is held at a temperature of 5~8℃ and a pressure of 1.0MPa for 2 hours to complete the gas-liquid phase maturation and compatibility, ensuring the near-azeotropic characteristics of the mixture are stable. Stirring is carried out continuously during the maturation process.

[0028] Furthermore, in step S3, the secondary precision purification system includes a deep dehydration module, a light component removal module, and a filtration and solid removal module. The deep dehydration module includes a 4A molecular sieve adsorption tower to reduce the moisture content of the finished product; the light component removal module uses a low-temperature light component removal tower to remove trace amounts of low-boiling-point impurities generated during the mixing process; and the filtration and solid removal module uses a ceramic membrane filter to remove trace amounts of solid particles from the finished product.

[0029] Furthermore, in step S3, the testing includes basic proportioning and purity testing, physical property testing, environmental and safety testing, and impurity testing. The basic proportioning and purity testing includes molar proportion and overall purity. The physical property testing includes phase change temperature drift, condensation pressure, evaporation pressure, and refrigeration capacity per unit volume. The environmental and safety testing includes ODP value, GWP value, flammability rating, and chemical stability. The impurity testing includes moisture, oxygen content, halide impurities, and solid particles.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] 1. In this invention, the optimized design of HFOs bicomponent compounding with a low proportion of HCs solves the problems of high GWP, contradiction between thermodynamic performance and environmental protection, and flammability risk of existing azeotropic refrigerants. The phase change temperature drift is only 0.2℃. There is no component separation in the operation of the system with load fluctuation and small pressure changes. After leakage, there is no need to vent and recharge. Only the same type of refrigerant needs to be added, which reduces maintenance costs. Moreover, no corrosive impurities such as hydrogen fluoride and acidic substances are generated, avoiding corrosion of pipelines.

[0032] 2. It meets the core requirements of low-temperature universality, high-load continuous operation, large-capacity safety, high energy efficiency and low operating costs in commercial scenarios. While maintaining the stable advantages of ultra-low GWP (Global Warming Potential), A1-grade non-flammability and near-azeotropic properties, it optimizes low-temperature thermodynamic performance through fine-tuning of component ratios. It is more compatible with the lubricating oils of commercial appliances and equipment compatibility. It can be directly matched with lubricating oils and is non-corrosive to copper, steel, aluminum and rubber seals. Thus, it is fully compatible with traditional refrigeration system materials and ensures the scope of application.

[0033] 3. In the refrigerant preparation process of this invention, low-temperature operation, inert gas protection, and real-time oxygen content monitoring are adopted to avoid the risk of R1270 combustion and explosion and the decomposition of HFOs, which meets the safety requirements of commercial production. Furthermore, the use of ceramic membrane filter element for filtration can effectively filter out trace solid particles to avoid affecting the subsequent mixing effect. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the preparation process according to one embodiment of this application. Detailed Implementation

[0036] To make the purpose, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] Example 1:

[0038] Reference Figure 1 An environmentally friendly azeotropic refrigerant formulation, comprising R1234ze(E), R1234yf, and R1270; specifically, the molar ratios are: R1234ze(E) 68-72%, R1234yf 13-17%, and R1270 13-17%. In this embodiment, R1234ze(E) is 70%, R1234yf is 15%, and R1270 is 15%.

[0039] In this embodiment, R1234ze(E) is 70%, R1234yf is 15%, and R1270 is 15%.

[0040] An environmentally friendly azeotropic refrigerant preparation process includes the following steps:

[0041] S1, Pretreatment: The raw materials are dehydrated, degassed, impurity removed, distilled, and protected to ensure that the purity of the raw materials is ≥99.99%, moisture content is <2ppm, and oxygen content is <5ppm.

[0042] S2, Material Mixing: The raw materials are mixed using a combination of graded metering and low-temperature, high-pressure static mixing.

[0043] S3, Finished Product Purification and Testing: The mixed and matured materials are further purified through a two-stage precision purification system to improve their purity, and are tested batch by batch.

[0044] In this embodiment, step S1 specifically includes the following steps:

[0045] S11, Dehydration treatment: A molecular sieve adsorption tower (4A+5A composite molecular sieve) is used. The raw material passes through the adsorption tower at a flow rate of 0.5m / s. The working temperature of the molecular sieve is 5~8℃ and the pressure is 0.8MPa. The moisture content of the raw material is reduced to <2ppm to avoid HFOs hydrolysis and ice blockage during subsequent mixing.

[0046] S12, Degassing and Impurity Removal: A vacuum degassing tower (vacuum degree of 0.098MPa) is used to remove dissolved oxygen, nitrogen and other inert gases from the raw materials, reducing the oxygen content to <5ppm, eliminating the risk of combustion and explosion of R1270 and the oxidative decomposition of HFOs;

[0047] S13, Precision Distillation: The raw material is passed through a packed precision distillation column (the height of the rectification section is 8m, and the packing is stainless steel θ mesh rings), the reflux ratio is controlled at 15:1, the bottom temperature is 20~25℃, and the top temperature is -20~-15℃, to remove particulate impurities such as halides and heavy hydrocarbons, and to improve the purity of the raw material to ≥99.99%;

[0048] This allows for sufficient mass transfer between the gas and liquid phases in the 8m rectification section of the distillation column, achieving efficient separation of trace amounts of difficult-to-separate impurities from the raw material. This ensures that the content of halides and heavy hydrocarbons in the distilled raw material is <0.001%, thereby meeting the requirement of a raw material purity of ≥99.99%.

[0049] S14, Inert gas protection: During the pretreatment process, a high-purity inert gas (such as 99.999% nitrogen) is introduced into the mixing system, and the system is kept at a slightly positive pressure (0.1~0.2MPa) to prevent air from seeping in.

[0050] In this embodiment, the mixing system includes a high-precision metering tank group, a mass flow meter, a static mixer, a mixing buffer tank, and a low-temperature chiller.

[0051] In this embodiment, step S2 specifically includes the following steps:

[0052] S21, Pre-cooling and inert gas replacement: Turn on the low-temperature chiller unit to lower the temperature of the metering tank group, static mixer, and mixing buffer tank to 5~8℃, and repeatedly fill the mixing system with high-purity inert gas for replacement 3-5 times (evacuate to -0.095MPa after each replacement) to ensure that the oxygen content of the system is <5ppm and the inert gas protection pressure is maintained at 0.15MPa;

[0053] S22, Two-component premixing: R1234ze (E) and R1234yf are fed synchronously in a molar ratio of 70:15 through a closed-loop control of a mass flow meter. The feed rate ratio of the two components is the same as the molar ratio. They are then fed into a static mixer for primary mixing.

[0054] After primary mixing, the material enters the front section of the buffer tank and stays for 30-45 minutes to complete the initial compatibility of HFOs components. During the process, the temperature of the premixed material is maintained at 5~8℃ and the pressure is 1.0MPa.

[0055] S23, Secondary mixing: The premixed materials are mixed in a molar ratio of 85:15, and R1270 is precisely fed into the static mixer through a mass flow meter at the same speed ratio as the molar ratio for secondary mixing.

[0056] During secondary mixing, the pressure inside the static mixer is controlled at 1.2 MPa, the temperature at 6~8℃, and the residence time of the material in the mixer is ≥20s. Molecular-level uniform mixing is achieved through the secondary mixing unit, with no local concentration deviation.

[0057] S24, Post-mixing maturation and stabilization: After secondary mixing, the material enters the mixing buffer tank and is held at a temperature of 5~8℃ and a pressure of 1.0MPa for 2 hours to complete the gas-liquid phase maturation and compatibility, ensuring the near-azeotropic characteristics of the mixture are stable. During the maturation process, continuous stirring is carried out (stirring speed is 30r / min, no shear heat) to prevent slight component separation.

[0058] In this embodiment, in step S3, the secondary precision purification system includes a deep dehydration module, a light component removal module, and a filtration and solids removal module. The deep dehydration module includes reducing the moisture content of the finished product by passing through a 4A molecular sieve adsorption tower; the light component removal module removes trace amounts of low-boiling-point impurities generated during the mixing process by passing through a low-temperature light component removal tower (temperature -30℃, vacuum degree -0.09MPa); and the filtration and solids removal module removes trace amounts of solid particles (such as molecular sieve powder and pipe rust) in the system by passing through a ceramic membrane filter element (filtration accuracy of 0.1μm).

[0059] In this embodiment, step S3 includes detection of basic ratio and purity, physical property detection, environmental protection and safety detection, and impurity detection. The detection of basic ratio and purity includes molar ratio and overall purity. The deviation of molar ratio must be < ±0.3%, and the overall purity must be ≥ 99.95%. Gas chromatography can be used.

[0060] The physical property tests include phase change temperature drift, condensing pressure, evaporating pressure, and refrigeration capacity per unit volume. The phase change temperature drift range should be <0.22℃, which can be achieved using a low-temperature boiling point tester. The condensing pressure is 0.82±0.02MPa, the evaporating pressure is 0.12±0.01MPa, which can be achieved using a pressure-temperature tester, and the refrigeration capacity per unit volume is 2780±50kJ / m³.

[0061] Environmental and safety testing includes ODP value, GWP value, flammability rating, and chemical stability. The ODP value should be 0 to meet environmental protection requirements and can be tested using ozone depletion potential. The GWP value should be 5.9±0.2 and can be tested using greenhouse effect potential. The flammability rating should be A1 to eliminate the risk of combustion and explosion and can be tested using ASHRAE34. Chemical stability means that there is no decomposition or acidic substances in the high-temperature aging test within 72 hours at 160℃.

[0062] Impurity detection includes moisture, oxygen content, halide impurities, and solid particles. Moisture content <5ppm prevents ice blockage in the refrigeration system; oxygen content <10ppm further eliminates the risk of combustion and explosion; halide impurities <2ppm prevent corrosion of equipment pipelines; and solid particles <0.1μm, i.e., no particles, prevents dirt blockage in the refrigeration system.

[0063] Example 2:

[0064] In this embodiment, the molar ratio of the azeotropic refrigerant mixture is: R1234ze(E) 72%, R1234yf 14%, and R1270 14%.

[0065] By increasing the proportion of the main component R1234ze (E) and proportionally reducing the proportions of R1234yf and R1270, targeted optimization of thermodynamic performance, process adaptability, and usage stability is achieved, while still meeting the phase change temperature drift requirements of azeotropic systems. It is suitable for use in all commercial refrigeration conditions, taking into account refrigeration energy efficiency, production safety, and equipment adaptability.

[0066] The phase change temperature drift is less than 0.15℃. Even if a small amount of leakage occurs in the refrigeration system, the composition ratio of the remaining refrigerant remains basically stable. Throughout the evaporation and condensation process of the refrigeration system, the molar ratio of the gas and liquid phases of the refrigerant is always close to 72:14:14, ensuring the continuity and stability of refrigeration performance and avoiding energy efficiency degradation due to composition changes.

[0067] The reduced molar ratio of R1270 significantly lowers the risk of combustion and explosion due to operational errors and equipment leaks, resulting in higher safety and more stable chemical properties. It is suitable for supermarket low-temperature island freezers, fresh food cold storage, and catering low-temperature freezers.

[0068] Example 3:

[0069] In this embodiment, the molar ratio of the azeotropic refrigerant mixture is: R1234ze (E) 68%, R1234yf 16%, and R1270 16%;

[0070] The reduced proportion of R1234ze (E) significantly improves the condensation heat exchange efficiency of the mixture. Under the core operating conditions of commercial air conditioning at 0~35℃, the system COP (coefficient of performance) is increased by 4%~6%, the cooling speed is faster, and the electricity operating cost is lower.

[0071] The slight improvement in R1270 further optimizes the refrigerant's flow and heat transfer characteristics, resulting in a significant increase in COP at medium temperatures and no performance degradation at low temperatures. It fully meets the requirements for light-load low-temperature refrigeration. Under commercial low-temperature conditions of -15℃, the evaporation pressure remains at a positive pressure of 0.10~0.14MPa, with no risk of ice blockage, gas blockage, or liquid slugging. It is suitable for central air conditioning or ducted air conditioners (0~25℃ medium-temperature refrigeration) in commercial office buildings and supermarkets, medium-temperature food freezers and refrigerators (2~8℃), and light-load low-temperature cold storage in the fresh food industry, greatly expanding its applicability.

[0072] It will be apparent to those skilled in the art that this application is not limited to the details of the exemplary embodiments described above, and that this application can be implemented in other specific forms without departing from the spirit or essential characteristics of this application. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this application is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalent elements of the claims are intended to be included within this application. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0073] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. An environmentally friendly azeotropic refrigerant formulation, characterized in that: The azeotropic refrigerant formulation includes R1234ze(E), R1234yf, and R1270; the specific molar ratio is: R1234ze(E) is 68-72%, R1234yf is 13-17%, and R1270 is 13-17%.

2. The environmentally friendly azeotropic refrigerant formulation according to claim 1, characterized in that: The R1234ze(E) is 70%, the R1234yf is 15%, and the R1270 is 15%.

3. A preparation process, according to the environmentally friendly azeotropic refrigerant formulation of claim 2, characterized in that: The preparation process Includes the following steps: S1， Pretreatment: The raw materials are dehydrated, degassed, impurity removed, distilled, and protected. S2, Material Mixing: The raw materials are mixed using a combination of graded metering and low-temperature, high-pressure static mixing. S3, Finished Product Purification and Testing: The mixed and matured materials are further purified through a two-stage precision purification system to improve their purity, and are tested batch by batch.

4. The preparation process of the environmentally friendly azeotropic refrigerant mixture according to claim 3, characterized in that: Step S1 specifically includes the following steps: S11, Dehydration treatment: A molecular sieve adsorption tower is used. The raw material passes through the adsorption tower at a flow rate of 0.5 m / s. The working temperature of the molecular sieve is 5~8℃ and the pressure is 0.8MPa. The moisture content of the raw material is reduced to <2ppm to avoid HFOs hydrolysis and ice blockage during subsequent mixing. S12, Degassing and Impurity Removal: A vacuum degassing tower is used to remove inert gases from the raw materials, reducing the oxygen content to <5ppm, eliminating the risk of combustion and explosion of R1270 and the oxidative decomposition of HFOs; S13, Precision Distillation: The raw material is passed through a packed precision distillation column with a reflux ratio controlled at 15:1, a bottom temperature of 20~25℃, and a top temperature of -20~-15℃ to remove particulate impurities and improve the purity of the raw material to ≥99.99%; S14, Inert gas protection: High-purity inert gas is introduced into the mixing system during the pretreatment process, and the system is kept at a slight positive pressure to prevent air from seeping in.

5. The preparation process of the environmentally friendly azeotropic refrigerant mixture according to claim 3, characterized in that: The mixing system includes a high-precision metering tank group, a mass flow meter, a static mixer, a mixing buffer tank, and a low-temperature chiller.

6. The preparation process of the environmentally friendly azeotropic refrigerant mixture according to claim 3, characterized in that: Step S2 specifically includes the following steps: S21, Pre-cooling and inert gas replacement: Turn on the low-temperature chiller unit to lower the temperature of the metering tank group, static mixer and mixing buffer tank to 5~8℃, and repeatedly fill the mixing system with high-purity inert gas for replacement 3-5 times. S22, Two-component premixing: R1234ze(E) and R1234yf are fed synchronously in a molar ratio of 70:15 through a closed-loop control of a mass flow meter. The feed rate ratio of the two components is the same as the molar ratio. They are then fed into a static mixer for primary mixing. After primary mixing, the material enters the front section of the buffer tank and stays for 30-45 minutes to complete the initial compatibility of HFOs components. During the mixing process, the temperature of the premixed material is maintained at 5~8℃ and the pressure is 1.0MPa. S23, Secondary mixing: The premixed materials are mixed in a molar ratio of 85:15, and R1270 is precisely fed into the static mixer through a mass flow meter at the same speed ratio as the molar ratio for secondary mixing. S24, Post-mixing maturation and stabilization: After secondary mixing, the material enters the mixing buffer tank and is held at a temperature of 5~8℃ and a pressure of 1.0MPa for 2 hours to complete the gas-liquid phase maturation and compatibility, ensuring the near-azeotropic characteristics of the mixture are stable. Stirring is carried out continuously during the maturation process.

7. The preparation process of the environmentally friendly azeotropic refrigerant mixture according to claim 6, characterized in that: In step S21, after each replacement, the system is evacuated to -0.095 MPa to ensure that the oxygen content is <5 ppm and the inert gas protection pressure is maintained at 0.15 MPa.

8. The preparation process of the environmentally friendly azeotropic refrigerant mixture according to claim 6, characterized in that: In step S23, during the secondary mixing, the pressure inside the static mixer is controlled at 1.2 MPa, the temperature is 6~8℃, and the residence time of the material in the mixer is ≥20s. Molecular-level uniform mixing is achieved through the secondary mixing unit, with no local concentration deviation.

9. The preparation process of the environmentally friendly azeotropic refrigerant mixture according to claim 3, characterized in that: In step S3, the secondary precision purification system includes a deep dehydration module, a light component removal module, and a filtration and solid removal module. The deep dehydration module includes a 4A molecular sieve adsorption tower to reduce the moisture content of the finished product; the light component removal module uses a low-temperature light component removal tower to remove trace amounts of low-boiling-point impurities generated during the mixing process; and the filtration and solid removal module uses a ceramic membrane filter to remove trace solid particles from the finished product.

10. The preparation process of the environmentally friendly azeotropic refrigerant mixture according to claim 3, characterized in that: In step S3, the testing includes basic proportioning and purity testing, physical property testing, environmental and safety testing, and impurity testing. The basic proportioning and purity testing includes molar ratio and overall purity. The physical property testing includes phase change temperature drift, condensation pressure, evaporation pressure, and refrigeration capacity per unit volume. The environmental and safety testing includes ODP value, GWP value, flammability rating, and chemical stability. The impurity testing includes moisture, oxygen content, halide impurities, and solid particles.

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