WO2021110008A1 - Composition for improving refrigeration energy efficiency of hfo1234yf - Google Patents

Abstract

Provided is a composition for improving the refrigeration energy efficiency of HFO1234yf, comprising a refrigerant HFO1234yf, a refrigerated lubricating oil PVE, a solubilizer absolute ethanol, and a high-polarity metal protective agent; according to mass percentage, the composition is: HFO1234yf: 85%; PVE: 12%; absolute ethanol: 1%; and metal protective agent: 2%; the metal protective agent is selected from chlorinated poly-α-olefins or chlorinated alkanes, the chlorinated poly-α-olefin being obtained by reacting poly-α-olefin with chlorine gas. The composition can effectively protect the compressor components while reducing the amount of refrigerated lubricating oil in an automobile air-conditioning system, extend its service life; at the same time, the invention can better improve the heat conduction performance of the condenser and the evaporator, increasing the air-conditioning refrigeration coefficient.

Description

Composition for improving refrigeration energy efficiency of HFO1234yf Technical field

The invention relates to a refrigerant composition, in particular to a composition for improving the refrigeration energy efficiency of HFO1234yf.

Background technique

For a China that takes the automobile industry as its pillar industry and has more than 320 million motor vehicles, the huge energy consumption and a series of environmental problems caused by it have attracted great attention from all parties. The air-conditioning system, which is the standard configuration of automobiles, not only provides a comfortable environment for drivers and passengers, but also further increases energy consumption and environmental pollution. In order to alleviate the environmental pressure caused by the use of car air conditioners, car air conditioners are shifting from function enhancement to efficiency enhancement. At present, some countries such as Europe, the United States, and Japan have issued relevant regulations to encourage the application of high-efficiency air-conditioning technology, and the my country Automobile Air-conditioning Association also plans to introduce related supporting measures to encourage the use of high-efficiency air-conditioning.

The role of air conditioners is to realize energy transfer, and the same is true for car air conditioners. In summer, the purpose of using air conditioners is to transfer heat from the car's driving space to the environment. The energy transfer of automobile air conditioning is accomplished by absorbing the heat in the passenger space when the "circulating refrigerant" in the evaporating box evaporates, and the condenser releases the absorbed heat to the environmental space outside the driving space. The process is: using a liquid phase refrigerant with a lower boiling point to evaporate in the evaporating box to absorb heat in the driving environment when the phase becomes low-temperature and low-pressure refrigerant vapor, and then the low-temperature and low-pressure refrigerant vapor is pumped into the compression chamber of the compressor Compressed into high-temperature and high-pressure refrigerant vapor and sent to the condenser, the high-temperature and high-pressure refrigerant vapor exchanges heat with the environment in the condenser, and releases the heat absorbed in the driving environment and condenses into a liquid refrigerant, liquid refrigeration The agent enters the evaporating box through the throttling device to evaporate and absorb heat again, so as to realize the transfer of heat from the riding space to the environment. In this process, the evaporator box and the condenser play the role of heat absorption and heat release. The heat exchange efficiency of this heat absorption and heat release will directly determine the quality and efficiency of the air conditioning refrigeration performance. One of the indicators that best reflects the performance of air conditioning refrigeration efficiency is the "refrigeration coefficient of performance", which is represented by COP (COP is the abbreviation of Coefficient Of Performance), which refers to the ratio of cooling capacity that can be obtained per unit power consumption. This refers to the amount of cold obtained refers to the heat absorbed by the evaporator, expressed in terms of cooling capacity. The formula is expressed as: COP = refrigeration capacity/input power, this coefficient is an important technical and economic indicator of the refrigeration system (refrigerator). A large refrigeration performance coefficient indicates high energy utilization efficiency of the refrigeration system.

At present, a combination of tetrafluoropropylene (HFO1234yf) refrigerant and polyvinyl ether (PVE) refrigerating lubricating oil has been widely used in the latest environmentally friendly automotive air conditioning systems as refrigeration cycle compositions. Among them, HFO1234yf uses heat absorption and heat release to complete the heat transfer during the phase change of the system, while PVE is responsible for lubricating moving parts such as compressors to avoid excessive wear and failure of moving parts such as compressors. However, in the evaporation box, due to the low temperature and the large amount of liquid HFO1234yf evaporating, the viscosity of the liquid composition composed of HFO1234yf and PVE will increase and the fluidity will deteriorate, so PVE is not easy to return to the compressor part, so it needs to be used in the system. Higher percentage of PVE. The compressor is mainly used to compress HFO1234yf gas. When the amount of PVE in the refrigeration system increases, the amount of PVE sucked into the compression chamber of the compressor also increases, and the proportion of HFO1234yf gas decreases accordingly, resulting in a decrease in the volumetric efficiency of the compressor. The cooling effect of automobile air-conditioning deteriorates. Reducing the ratio of PVE will cause excessive wear of the metal moving parts of the compressor and shorten its service life. Additional anti-wear agents, extreme pressure agents, etc. need to be added to enhance the lubricity and reliability of the moving parts of the compressor. In addition, the PVE will form an adsorption film on the aluminum tube wall due to the adsorption effect. The heat in the riding space is transferred through the aluminum tube wall of the evaporation box to the PVE adsorbed on the tube wall with a small amount of HFO1234yf dissolved in it. Then the heat is transferred to the lower temperature HFO1234yf vapor to complete the heat exchange. During the heat conduction process, since the PVE film adsorbed on the tube wall has a high thermal resistance and a certain thickness, the heat exchange efficiency of the process is greatly reduced. In the condenser of another heat exchange component, because more high-temperature liquid HFO1234yf is almost miscible with PVE, the composition of HFO1234yf and PVE has low viscosity and fast flow speed, and PVE is not easy to accumulate, so its heat exchange efficiency is better. The evaporator box appears slightly higher. Even so, because the PVE in the composition has a certain polarity, it can still form a high-strength oil film with a certain thickness on the surface of the aluminum condenser pipe under the condition of higher temperature, lower viscosity, and faster flow rate of the condenser. The oil film with low thermal conductivity also hinders the heat transfer that occurs in the condenser.

Summary of the invention

The technical problem to be solved by the present invention is to provide a refrigerant composition which can effectively protect the compressor components and prolong their service life while reducing the amount of refrigerated lubricating oil in the automobile air conditioning system. Improve the heat transfer effect of the condenser and the evaporating box, and increase the refrigeration coefficient of the air conditioner.

The technical solution adopted by the present invention to solve the above-mentioned technical problems is: a composition for improving the refrigeration energy efficiency of HFO1234yf, the composition comprising refrigerant HFO1234yf, refrigerated lubricating oil PVE, solubilizing anhydrous ethanol and a highly polar metal protective agent.

According to mass percentage, its composition is:

HFO1234yf: 83-85%

PVE: 12-15%

Absolute ethanol: 1%

Metal protective agent: 1 to 2%.

The metal protective agent is selected from chlorinated poly-α-olefins or chlorinated alkanes, and chlorinated poly-α-olefins are prepared from poly-α-olefins and chlorine in the following specific ways:

(1) Adding 70% of its volume to the chlorination reactor, which is commercially purchased poly-α-olefin;

(2) Introduce liquid chlorine into the liquid chlorine vaporizer through the regulating valve to maintain the vaporizer pressure at 195～198kPa, open the flow meter needle valve to introduce chlorine into the chlorination reactor;

(3) Turn on the built-in UV lamp in the chlorination reactor, perform chlorination activation treatment, and control the reaction temperature at 40-60°C;

(4) When the reactant in the chlorination reactor turns into amber color, stop the chlorine gas and turn off the UV lamp to obtain the crude product of chlorinated poly-α-olefin;

(5) Pour the crude chlorinated poly-α-olefin product into the degassing tower for 3-4 hours to remove the hydrogen chloride and unreacted chlorine gas, and neutralize it with 40% caustic soda at 100°C to pH=6～ 7. Finally, the desired poly-α-olefin is obtained by dehydration and filtration.

The number of chlorine atoms in the chlorinated poly-α-olefin can be controlled by controlling the reaction time and the rate of chlorine gas introduction.

Chlorinated alkanes can be chlorinated paraffin-40 or chlorinated paraffin-42.

Preferably, in terms of mass percentage, its composition is:

HFO1234yf: 85%,

PVE: 12%,

Absolute ethanol: 1%,

Metal protective agent: 2%.

The HFO1234yf in the above components has a molecular formula of CF ₃ CF=CH ₂ , a molecular mass of 114, a boiling point of -29.5°C, a critical temperature of 94.7°C, and a critical pressure of 3.38 MPa.

The poly-α-olefin in the above components is mainly C10, with a flash point of 260°C, a pour point of -45°C, and a viscosity index of 133VI.

The chlorinated alkanes in the above components have a molecular formula of C ₂₅ H ₄₅ C _l7 , a molecular mass of 594.81, a freezing point of -30°C, a relative density of 1.16 g/cm ³ , and a flash point of 298.4°C.

The molecular formula of PVE in the above components is CH ₂ =CH-OR, and R is an alkyl group or an aryl group.

The absolute ethanol in the above components has a molecular formula of CH ₃ CH ₂ -OH, a molecular mass of 40.07, a boiling point of 78.3°C, a critical temperature of 243.1°C, and a critical pressure of 6.38 MPa.

Compared with the prior art, the refrigerant composition provided by the present invention has the following advantages:

When the refrigerated lubricating oil attached to the metal surface of the compressor contains chlorinated poly-α-olefins or chlorinated alkanes with higher polarity and better load and lubricating ability, it is easy to be in the friction pair of the relative movement of the compressor. At the same time, a chemical protective film is formed under the higher temperature conditions of boundary lubrication, thereby avoiding the metal wear of the moving parts of the compressor due to the reduction of the use of refrigerated lubricating oil, and prolonging the service life of the compressor. In addition, chlorinated poly-α-olefins or chlorinated alkanes, which have a higher polarity than the refrigerated lubricating oil, can reduce the adsorption of the refrigerated lubricating oil film with high thermal resistance on the surface of the heat exchange aluminum tube through "competitive adsorption". -The thermal resistance of olefins or chlorinated alkanes is low, and the adhesion thickness is only molecularly different, so it has a smaller thermal resistance and higher heat transfer efficiency, and the solubilizer in the composition can reduce the viscosity of the composition to make the low temperature part The refrigerated lubricating oil in the evaporator is easier to return and the power consumption of the conveying cycle is reduced, thereby effectively improving the heat exchange efficiency of the condenser and the evaporator and the refrigeration performance of the automobile air conditioner.

Detailed ways

Hereinafter, the present invention will be further described in detail with reference to the embodiments.

First, experiments were conducted with only HFO1234yf and PVE as the circulating composition, and the optimal use ratio of PVE was screened when the metal protective agent and solubilizer were not introduced into the composition. According to the highest mass percentage (%) generally used, the ratio of refrigerant to refrigerating lubricating oil is 60:40, 65:35, 70:30, 75:25, 80:20, 85:15, 84:16, 83: 17 The coefficients of refrigeration performance of automobile air conditioners were tested under the simulation conditions of the same working conditions, and the results are as follows:

PVE(%)	0	5	0	5	0	7	6	5
COP	.77	.91	.02	.19	.28	.35	.44	.52

According to the above experimental results, as the use ratio of refrigerated lubricating oil in the circulating composition decreases, its energy efficiency ratio is correspondingly improved. However, when the proportion of refrigerating lubricants used was reduced to 17%, the noise produced by the refrigeration compressors began to appear and became more pronounced as the proportion of refrigerated lubricants decreased. At the same time, the temperature rise of the refrigeration compressors also began to rise significantly (exhaust temperature). Start to rise), the reason is that the compressor has deteriorated the lubrication conditions of the system due to the decline in the use of refrigerated lubricant. Therefore, the use ratio of refrigerated lubricating oil should not be less than 17% when the metal protective agent and solubilizer are not introduced into the composition.

Example

The preparation process of the refrigerant composition containing metal protective agent chlorinated poly-α-olefin or chlorinated alkane and solubilizer absolute ethanol is as follows:

First, fully mix PVE and chlorinated poly-α-olefin or chlorinated alkanes at normal temperature and pressure to form a homogeneous liquid mixture; then add the solubilizer absolute ethanol to the above-mentioned liquid mixture to fully mix the three to form a homogeneous phase ; Finally, the refrigerant HFO1234yf is added to the resulting ternary mixed liquid, and the refrigerant composition is obtained after being fully dissolved.

Although chlorinated poly-α-olefins or chlorinated alkanes and PVE can be freely miscible, the solubility of chlorinated poly-α-olefins or chlorinated alkanes, PVE, and mixtures of the two with refrigerants is limited. , Especially in the low temperature environment of the evaporator, layering will occur due to the decrease of solubility, so it is necessary to introduce the solubilizer absolute ethanol, and the solubilizer itself does not have a heat transfer effect, so the amount of the solubilizer absolute ethanol is to make each component Just completely dissolved as the standard. Because PVE, chlorinated poly-α-olefins or chlorinated alkanes and absolute ethanol all have strong water absorption, avoid contact with air during miscibility, and the resulting composition should be stored in a closed container.

After the refrigerant compositions with different mass fraction ratios were prepared according to the above method, performance tests were performed respectively. The results are shown in Table 1, where:

Condenser and evaporator heat exchange performance test: The test consists of a universal parallel flow automotive air-conditioning condenser with a size of 570mm×350mm×20mm. The driving device is a set of variable frequency and variable speed 4KW motor, a set of adjustable power and rated maximum electric heating power. It is a 2KW heater, an SSJ96 air-conditioning sliding vane circulating pump, the throttle device is an orifice tube with a diameter of 1.2mm and a length of 50mm, and a unit with a capacity of 170L can control the heat absorption (discharge) environment in- It is carried out in a closed heat preservation circulating system composed of a 40℃ to 85℃ calorimeter, temperature, pressure, and flow transmitters. Comparing the circulating composition of different components to simulate automobile air conditioner under the operating environment conditions 85℃, the flow composition in the condenser releases heat to the temperature of 32℃ in the calorimeter, and the 3℃ flow composition in the evaporator from the temperature of 25℃ The heat exchange performance of the medium in the calorimeter.

Car air conditioner refrigeration performance coefficient change test: The test consists of a universal parallel flow car air conditioner condenser with a size of 640mm×420mm×25mm. The driving device is a set of variable frequency and variable speed 4KW motor, a set of adjustable power and a rated maximum electric heating power of 6KW. Heater, a YFB508, a 164cc/r fixed displacement reciprocating piston air-conditioning compressor, a Volkswagen Passat B5 Lingyu evaporator, the throttling device is a 1.4mm diameter orifice tube with a length of 80mm , A calorimeter with a capacity of 220L that can control the heat absorption (discharge) environment at -40℃ to 85℃, temperature, pressure, flow transmitter and dynamic torque sensor (can instantly measure torque, speed, current power) It is carried out in a closed insulation circulation system composed of such components. The experiment adopts the national standard (GB5773-04) "Second Refrigerant Quantity Thermal Method" to measure the shaft input power and refrigeration capacity of the refrigeration compressor and obtain the value of the refrigeration coefficient COP. This test compares the COPs of different circulating compositions in a simulated automobile air conditioner at an engine speed of 1800 rpm and an ambient temperature of 35°C.

The test of the composition on the change of metal anti-wear performance: The test was conducted on a four-ball machine produced by Shanghai Experimental Instrument Factory in accordance with SH/T0189-92 "Lubricant Anti-wear Performance Test Method". The test ball is a chrome alloy steel ball made of Gcr15 with a diameter of 12.7mm, and its Rockwell hardness is a special test ball for the HRC64-66 standard. The long grinding experiment was carried out under the conditions of load 392N, rotation speed 1200 rpm, and test time of 60 minutes, and the wear scar diameter of the three test balls was used as the test reference and comparison result. This test compares the diameter of the ball wear scar of different compositions. The smaller the value of the ball wear scar, the better the wear resistance.

Table 1: Performance comparison of Examples 1-4.

The above results show that the addition of metal protective agent chlorinated poly-α-olefins or chlorinated alkanes can effectively reduce the amount of refrigerated lubricating oil. With the decrease of its amount, the heat exchange efficiency and refrigeration of the condenser and the evaporating box in the automobile air conditioning system The efficiency has also been improved, and the introduction of chlorinated poly-α-olefins or chlorinated alkanes has also significantly improved the wear resistance of metals. But when the amount of refrigerating lubricant is less than 12%, the compressor starts to be abnormal. Therefore, the optimal ratio of the refrigerant composition is HFO1234yf: 85% + PVE: 12% + anhydrous ethanol: 1% + metal protective agent : 2%. Under this condition, the amount of refrigerated lubricating oil in the automobile air-conditioning refrigeration system is reduced from the original 17% to 12%, the heat release efficiency of the condenser and the evaporator are increased by 2.87% and 7.83%, respectively, and the COP is increased by 7.89%.

The working principle of the refrigerant composition is:

When higher-polar chlorinated poly-α-olefins or chlorinated alkanes coexist with relatively low-polar PVE on the heat exchange surface of the condenser or evaporator in a liquid state, chlorinated poly-α-olefins or chlorinated alkanes Due to the uneven distribution of the electron cloud in the molecule, it is negatively charged, so that the force between it and the metal surface increases the electrostatic association force in addition to the van der Waals force. This association force is much stronger than the PVE film solely relying on the van der Waals interaction between the molecules. The adhesion of the force to the metal surface. Therefore, chlorinated poly-α-olefins or chlorinated alkanes can easily replace the PVE attached to the metal surface, and the chlorinated poly-α-olefins or chlorinated alkanes, which have lower thermal resistance and are only molecularly thick, have high thermal resistance to PVE. The replacement of the membrane will greatly improve the heat exchange performance of the condenser and the evaporator; the high-polarity chlorinated poly-α-olefin or chlorinated alkane has a low friction coefficient, and it is easy to have a higher boundary lubrication between the friction pairs of the compressor relative to the movement. A chemical protective film is formed under high temperature conditions, which can prolong the service life of the compressor and provide better lubricity, reduce frictional resistance and reduce shaft input power; the introduction of solubilizer absolute ethanol can increase the solubility of HFO1234yf in PVE , Reduce the viscosity of the PVE, so that the PVE can pass through the condenser and the evaporator pipe more freely and effectively return to the air-conditioning compressor to reduce the power consumption of the conveying cycle, which also improves the heat exchange efficiency of the evaporator.

Claims (10)

1. A composition for improving the refrigeration energy efficiency of HFO1234yf, which is characterized in that it comprises refrigerant HFO1234yf, refrigerated lubricating oil PVE, solubilizer anhydrous ethanol and a highly polar metal protective agent, and its composition is HFO1234yf: 83-85 according to mass percentage %, PVE: 12-15%, absolute ethanol: 1%, metal protective agent: 1-2%; the metal protective agent is selected from chlorinated poly-α-olefins or chlorinated alkanes; the chlorinated poly-α- Olefins are made by reacting poly alpha-olefins with chlorine gas.
2. The composition for improving refrigeration energy efficiency of HFO1234yf according to claim 1, wherein the composition is HFO1234yf: 85%, PVE: 12%, absolute ethanol: 1%, and metal protective agent: 2 in terms of mass percentage. %.
3. The composition for improving refrigeration energy efficiency of HFO1234yf according to claim 1, wherein the chlorinated poly-α-olefin is prepared by the following specific methods:

   (1) Add 70% of the poly-α-olefin by volume to the chlorination reactor;

   (2) Introduce liquid chlorine into the liquid chlorine vaporizer through the regulating valve to maintain the vaporizer pressure at 195～198kPa, open the flow meter needle valve to introduce chlorine into the chlorination reactor;

   (3) Turn on the built-in UV lamp in the chlorination reactor, perform chlorination activation treatment, and control the reaction temperature at 40-60°C;

   (4) When the reactant in the chlorination reactor turns into amber color, stop the chlorine gas and turn off the UV lamp to obtain the crude product of chlorinated poly-α-olefin;

   (5) Pour the crude chlorinated poly-α-olefin product into the degassing tower for 3-4 hours to remove the hydrogen chloride and unreacted chlorine, and neutralize it with 40% caustic soda at 100°C to pH=6～ 7. Finally, the desired poly-α-olefin is obtained by dehydration and filtration.
4. The composition for improving refrigeration energy efficiency of HFO1234yf according to claim 3, wherein the number of chlorine atoms in the chlorinated poly-α-olefin can be controlled by controlling the reaction time and the rate of chlorine gas introduction.
5. The composition for improving the refrigeration energy efficiency of HFO1234yf according to any one of claims 1 to 4, wherein the HFO1234yf has a molecular formula of CF ₃ CF=CH ₂ , a molecular mass of 114, and a boiling point It is -29.5°C, the critical temperature is 94.7°C, and the critical pressure is 3.38MPa.
6. The composition for improving the refrigeration energy efficiency of HFO1234yf according to any one of claims 1 to 4, wherein the poly-α-olefin is mainly C10, has a flash point of 260°C, and a pour point of -45℃, viscosity index is 133VI.
7. The composition for improving refrigeration energy efficiency of HFO1234yf according to claim 1, wherein the chlorinated alkane has a molecular formula of C ₂₅ H ₄₅ C _l7 , a molecular mass of 594.81, a freezing point of -30°C, and a relative density It is 1.16g/cm ³ and its flash point is 298.4°C.
8. The composition for improving refrigeration energy efficiency of HFO1234yf according to claim 1, wherein the chlorinated alkane is chlorinated paraffin-40 or chlorinated paraffin-42.
9. The composition for improving refrigeration energy efficiency of HFO1234yf according to claim 1, wherein the molecular formula of the PVE is CH ₂ =CH-OR, and R is an alkyl group or an aryl group.
10. The composition for improving the refrigeration energy efficiency of HFO1234yf according to claim 1, wherein the absolute ethanol has a molecular formula of CH ₃ CH ₂ -OH, a molecular mass of 40.07, a boiling point of 78.3°C, and a critical temperature It is 243.1°C and the critical pressure is 6.38MPa.