JPH05502468A - Azeotrope-like composition of 1,1,2,2-tetrafluoroethane and 1,1-difluoroethane - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] 1. 1. 2. 2-tetrafluoroethane and the present invention are characterized by: 1. 1. 2 ．． Azeotrope-like mixture of 2-tetrafluoroethane and 1,1-difluoroethane Regarding the composition. These mixtures are useful as refrigerants for heating and cooling applications. It is for use.

Background of the invention Fluorocarbon-based fluids for refrigeration, air conditioning and heat pump applications It has been widely used in industry.

Vapor compression is a form of refrigeration. In its simplest form, vapor compression transfers the refrigerant from the liquid to the vapor phase by heat absorption at low pressure, followed by heat removal at high pressure. It involves changing from vapor to liquid phase by First, contact with the body to be cooled The refrigerant is vaporized in an evaporator. The pressure in the evaporator is The boiling point of the medium is such that it is below the temperature of the body being cooled. Therefore, the heat is to the refrigerant, and vaporizes the refrigerant. The generated steam is then transferred to the evaporator removed by a compressor to maintain low pressure in the generator. Next, the temperature of the steam is increase the temperature and pressure by applying mechanical energy through a compressor . The high pressure steam is then passed through the cooler, so that the heat is exchanged by the cooler medium do. Significant and latent heat is removed by subsequent condensation. Then the thermal liquid refrigerant passes through an expansion valve 9 and is ready for circulation again.

The main purpose of cooling is to remove energy at low temperatures, but the main purpose of heat pumps is The key objective is to add energy with even more humid coal. The heat pump Therefore, it is considered to be a reverse cycle system, and the condensation operation is performed by a cooling evaporator. This is done alternately with the operation of

Certain chlorofluorocarbons are characterized by their chemical properties and physical properties. Widely used in refrigeration applications including air conditioning and heat pump applications due to different combinations. It's here. Most refrigerants used in vapor compression systems are single component fluids or It is an azeotrope. Single component fluids and azeotropes are characterized by the fact that they are isothermal and isobaric. It is characterized as having a constant boiling point because it exhibits evaporation and condensation of . Cool the azeotrope It is known in the art to use media such as Downing, R.C., “Fluorocarbon Refrigerant Handbook” (Fluorocarbon Refrigerant, Handbook )” 1.139-158, Prentice-Ha ll), 1988, as well as U.S. Pat. nol, 993 specification and the same no. See No. 2,641.579.

Azeotropes and azeotrope-like compositions are those that can be fractionated by boiling or evaporation. It is desirable because it does not. This behavior is similar to the evaporators described above where these refrigerants are used. In air compression equipment, condensed substances are produced in the production process for cooling or heating purposes. Preferably, if the refrigerant does not have a constant boiling point, i.e. it is not azeotrope-like. , resulting from fractionation and separation or evaporation and condensation, resulting in undesirable refrigerant distribution. This may disrupt cooling or heating.

Non-azeotropic mixtures with refrigerants are disclosed in, e.g., U.S. Pat. No. 536, even though improvements in its non-azeotropic refrigerant formulations Even if the ability to exhibit thermodynamic performance is often disclosed in the literature, commercial It has never been widely used for any purpose. For example, Tea Atwood (T.

The Promis eand the Probl, em)j, American Society of Mechanical Engineers, Winter Annual Meeting, Paper 86-WA/HT-61, 1-986 and M.O. McLinden (M. OMcLinden et al., “The properties of pure and mixed refrigerants in vapor compression cycles. Methods for Comparing the Per formation of Pure and l[ixed Refrigera nts in the Vapor Compression Cycle)J ,Int,J,Refrig,.

10.318 (1987). Non-azeotropic mixtures are They require some hardware changes.

Added difficulty when changing and repairing cooling equipment avoids non-azeotropic mixtures This is the main reason. The situation is such that an inadvertent leak in the system is even more complex when it occurs during repairs. Change the composition of the mixture (- to change the system can affect system pressure and system performance. Therefore, a non-azeotrope If one component of the compound is flammable, it may be necessary to separate it (and thus bring its composition into the flammable range). can be moved, potentially with the opposite result.

Technically, new fluorocarbons offer an alternative for cooling and heating pump applications. The search for carbon-based azeotrope-like mixtures continues. □In recent years, completely halo Generated chlorofluorocarbons are linked to the depletion of the Earth's protective ozone layer. Environmentally acceptable fluorocarbons have been implicated in causing environmental problems. Carbon-based refrigerants are of particular interest. Through a mathematical model, 1. 1. 1. 2-tetrafluoroethane (RFC-134a) and 1,1-difluoro Hydrofluorocarbons such as ethane (RFC-152a) are It is completely clear that halogens are contributing to global ozone depletion and global warming. It has no negative impact on atmospheric chemical phenomena because it can be ignored compared to the This has been proven.

Alternatives to CFCs further include chemical stability, low toxicity, flame retardancy and utilization efficiency. 1. have those properties specific to . must be maintained. The latter characteristic is e.g. Increased loss of thermodynamic performance or energy efficiency relative to electrical energy Demand-driven increased use of fossil fuels can lead to secondary environmental effects. Important in cooling applications such as air conditioning. Furthermore, the ideal CFC refrigerant replacement is , major engineering changes to conventional vapor compression techniques currently used with CFC refrigerants. It must not require any changes.

Therefore, it is an object of the present invention to: 1. be useful in cooling and heating applications; 1. Based on 2-tetrafluoroethane and 1,1-difluoroethane The object of the present invention is to provide novel azeotrope-like compositions.

Another object of the invention is to develop a novel environmentally acceptable method for use in the aforementioned applications. The objective is to provide a refrigerant that can

Other objects and advantages of the invention will become apparent from the description below.

Summary of the invention The present invention is useful in heating and cooling applications: 1. 1. 1. 2-te Novel environmentally acceptable compounds with I-difluoroethane and 1,1-difluoroethane The present invention relates to azeotrope-like compositions that can be mixed.

Description of the invention According to the present invention, the new azeotrope-like compositions are: 1. L 1. 2-tetraful It was discovered to contain oloethane and 1,1-difluoroethane. azeotropic mixture The product-like composition is 1+1. About 5 to about 90 weight of 1.2-tetrafluoroethane % and about 10 to about 95% by weight of 1,1-difluoroethane, and its vapor pressure is At 20°C, it is 76 ps ia ± 5 ps i, a. These) U, fl things are such that they exhibit an essentially constant vapor pressure over the composition and over the aforementioned ranges. It is azeotrope-like because it exhibits essentially the same liquid and vapor compositions.

In a preferred embodiment of the invention, such an azeotrope-like composition is 1 About 40 to about 85% by weight of 1,2-tetrafluoroethane and 1,1-diphroethane It contains about 15 to about 60% by weight of fluoroethane, and its vapor pressure is 76 psia at 20°C. ±3ps ia.

More than about 80% by weight 1, 1. 1. Vapor phase containing 2-tetrafluoroethane The string hook is a Bureau of Mines type knee. It was determined to be flame retardant at ambient conditions in air using a geometer device.

Azeotrope-like composition of the invention consisting of HFC-'L52a and HFC-134a Things don't separate. Furthermore, they are dichlorodifluoromethane (CFC-12) , exhibits numerous advantages over HFC-134 and HFC-152a. for example, Azeotrope-like mixtures are flame retardant when RFC-134a exceeds 80% by weight. , thereby allowing easily flammable RFC-152a vapors to be stored and stored in pure form. reduces the risk of explosion that may occur if handled.

Furthermore, azeotrope-like mixtures have zero ozone depletion potential and long atmospheric lifetimes. are short and therefore their contribution to greenhouse warming can be ignored.

This means that CFC-12 has a high possibility of ozone depletion and a relative possibility of greenhouse warming. Contrasted with being high.

The energy efficiency and cooling capacity of the azeotrope-like compositions of the present invention are similar to that of pure HFC. -134a, and furthermore, the 134a/152a compositions Significantly reduces direct and indirect greenhouse warming potential over pure HFC-134a. reduce

The azeotrope compositions of the present invention uniquely possess all of the desirable characteristics of an ideal 'I@ medium. i.e. safe for use, flame retardant, zero ozone depletion potential, ignore The most suitable pure of fluoromethane or fluoroethane fluid, i.e. -19°C to -30°C ( This range represents the boiling point of most air conditioning and refrigerant common fluids in use today. compared to fluorocarbon refrigerants, which boil at In summary, RFC-15 2a/RFC-134a in an effective amount, the thermodynamic performance was improved. A flame retardant, non-segregating, environmentally acceptable azeotrope-like refrigerant results.

The term "azeotrope-like" as used herein refers to 1. 1. 1. 2-tetrafluoroethane and 1,1-difluoroethane The mixture of the present invention has used in conjunction with All compositions within the indicated range as well as those outside the indicated range. The species composition is azeotrope-like, as defined in more detail below.

From basic principles, the thermodynamic state of a fluid is determined by four variables: pressure, temperature. , liquid composition and vapor composition, i.e. defined by P-T-:X-Y, respectively. be done. A co'4 mixture is a compound in which X and Y are defined as P and T and are equal to 1. Two types of cases It is a characteristic property of systems that have similar components. In fact, this can be either a component or a phase change. It is unlikely that they will separate during the process, and therefore, the cooling and It means that it is useful in JU thermal applications.

For the purpose of this discussion (7), an azeotrope-like composition is defined as A true azeotrope with respect to its point character or its property of not fractionating by boiling or evaporation. It is meant to mean that it behaves like a compound. Therefore, this In a system like this, the composition of the vapor produced during evaporation is the same as that of the original liquid. one or substantially the same. Therefore, during boiling or evaporation, the liquid composition changes Even if it does change, it changes very little. This applies to liquids and and non-azeotrope-like compositions whose vapor composition changes substantially upon evaporation or condensation. be compared.

If the vapor and liquid phases have the same composition, it is and that the boiling point versus composition curve passes through an absolute maximum or absolute minimum at this composition. can be shown. One of the two conditions, i.e. the same liquid and vapor composition or If < indicates the existence of a boiling point maximum, the system is an azeotropic mixture. compound and must be followed by the other condition.

One way to determine whether a candidate mixture is azeotrope-like within the meaning of the invention method under conditions expected to separate the mixture into its W# components (i.e. In other words, the sample is distilled using a single stage of decomposition. The mixture is a non-azeotrope or non-azeotrope-like, the mixture is fractionated, i.e. first distilled off. It is separated into its various components, including the lowest boiling component. The mixture is azeotrope-like contains all the components of the mixture and has a constant boiling point or is listed as a single substance. A somewhat finite amount of the first distillation fraction is obtained which moves. This phenomenon shows that the mixture is azeotropic when it is not mixture-like, i.e. when it is not part of an azeotrope system. It is impossible for it to occur.

From the above, it is a natural result and 1. Another feature of azeotrope-like compositions is that There exists a range of compositions containing various proportions of That's what it means. All such compositions are referred to as azeotropic mixtures as used herein. It means that it is included in the term ``thing-like point''. - Examples and 1. So, under various pressures, The composition of a given azeotrope, as well as the boiling point of that composition, changes at least slightly. It is well known that Therefore, the azeotrope of A and B is a unique type of shows a relationship, but has a composition that changes depending on temperature and/or pressure. Current As is readily understood by those in the industry, the boiling point of an azeotrope varies with pressure. Ru.

In one embodiment of the invention, the azeotropic mixture of the invention! The il paraboloid is an azeotrope After condensing the refrigerant containing the compound composition, the refrigerant near the main body to be cooled is evaporated. It can be used in a method for performing cooling including.

In another embodiment of the invention, the azeotrope-like composition of the invention is heated Heating that uses the condensation of refrigerant near the main body (after which the refrigerant is evaporated) It can be used in a method to perform

For the purposes of this application (and as mentioned in Section 7 above) Embodiments are commonly referred to as heat exchange applications.

'J-,1,1,2-tetrafluoroethane of the novel azeotrope-like compositions of the present invention and 1. l-Difluoroethane is a known substance. Preferably they is used at a sufficiently high purity to avoid introducing adverse effects due to the constant boiling point nature of the system. Should.

The present composition or the inclusion of additional components to create a novel azeotrope-like composition. It must be understood that this is possible. Any such composition is As long as the product is essentially of constant boiling point and contains all the essential components listed herein, are considered to be within the scope of the present invention.

Furthermore, the azeotrope-like compositions of the present invention produce novel azeotrope-like compositions such as 1- May contain ingredients that may be harmful. In particular, U.S. Patent No. 4,755.316 Adding lubricants as mentioned in the specification without departing from the scope of the invention be able to.

The invention is more fully illustrated by the following non-limiting examples.

Example 1 In this example, ], L i, 2-te)-difluoroethane and 1,1-diphthalene Certain compositions with fluoroethane are azeotrope-like, i.e., essentially has the same liquid and the above composition, and has a constant boiling point, i.e. within this range. [- indicates an essentially constant vapor pressure for the composition within the range [-].

Vapor-liquid equilibrium experiments were conducted with a mixture of HFC-134a and RFC-152a at ca. This was done by manufacturing in a 50 cubic centimeter container. electromagnetic drive star Equipped with a pressure transducer that is accurate to +/-0.2% The vessel was submerged in a constant temperature bath controlled to within ±0.02°C. constant steam pressure reading Once thermal equilibrium is achieved, as determined by Body samples were collected from the containers and analyzed by standard gas chromatography methods.

This method is carried out in HFC-152a with RFC-134a of approximately 25.50 and 75 A nominal mixture of 3 mole % and 3 temperatures, -20, 20 and and repeated at 60°C. Table ■ summarizes the results of these experiments.

The data presented in Table ■ are based on chromatography with an experimental imprecision of ±2.0% by weight The equipment involved in the analysis shows that the vapor and liquid compositions are essentially the same. There is. The vapor pressure data measured at =20°C shows a minimum value for the composition and is This is evidence of compound behavior. The vapor pressure of the formulation ranges from about 5 to about 90% by weight and for a composition range of about 10 to about 95% HFC-152a. essentially constant to within ±5 ps i a, i.e. these formulations is a constant boiling point, ie azeotrope-like.

Example 2 In this example, the azeotrope-like RFC-134a/RFC-152a blend is When compared to FC-134a alone, it is expected to have some performance advantages. show.

The performance of a refrigerant at specific operating conditions is measured by the coefficient of performance and the capacity of the refrigerant. can be done. The coefficient of performance, COP, is a universally acceptable measure; Especially in certain heating or cooling cycles that involve evaporation or condensation of refrigerant. Useful for expressing the relative thermodynamic efficiency of refrigerants. In cooling engineering, this The term refers to the energy given by the compressor when compressing vapor. Represents the rate of cooling required. The capacity of a refrigerant represents the volumetric efficiency of the refrigerant. compressor technology For users, this value is the pressure to pump the amount of heat for a constant volumetric flow rate of refrigerant. Represents the capacity of the compressor. In other words, given a particular compressor, the volume is high The refrigerant provides greater cooling or heating efficiency.

-20,036,035,917,1 -20,064,], 63,4 17.2-20.2 77.4 79,5 17.7-20.0 100.0 1.00.019320,OO,00,07 4,7 20,034,736,475,0 20,160,863,476,7 20,078,480,179,0 20,0100,0100,082,960,00,00,0218,9 60,034,736,7219,5 60,160,863,2225,7 Azeotrope profile of 78/22 HFC-134a/HFC-152a (by weight) The performance of the compound was demonstrated in a typical automotive air conditioner operated under controlled laboratory calorimeter conditions. evaluated with the device. The compressor and condenser areas of the air conditioning cycle should be kept at a 100°F limit. kept in a controlled environment. to the condenser and the condenser using a thermocouple temperature of the air stream from the compressor at the outlet and suction, as well as at the condenser outlet. The temperature of the refrigerant was measured. The compressor uses an electric motor at a constant speed of 1188 rotations/rotation. was operated on. A power integrating meter was used to determine the mechanical work input to the compressor.

The removal of heat from the condenser environment is determined by the measured flow to the cooling coils in the condenser chamber. Achieved using cold water flowing in volume. The capacity of the air conditioning system is Determined by performing an energy balance.

The evaporator and expansion valve sections of the air conditioning cycle are at 100'F and relative The humidity was maintained at 40%. Using a thermocouple, the output from the evaporator is and from the accumulator? The temperature of lI was measured. Compressor suction and discharge lines using four pressure transducers located in the chamber and immediately after the condenser and accumulator. The refrigerant pressure throughout the cycle was measured. Two sets of electric heaters in the evaporator room The evaporator was constantly adjusted to balance the heat removed by the evaporator.

The test was conducted using three types of refrigerants: CFC-12 (dichlorodifluoromethane) and HF. Azeotrope of HFC-134a/RFC-152a of C-143a and 78/22 The conditions detailed above for compound-like formulations were followed. CFC-12 is used for air conditioning and A fully halogenated chlorofluorocarbon that has been widely used in It is. CFC-12 is contributing to the depletion of Earth's stratospheric ozone layer This was confirmed. Each test shall be performed at least with a measured COP that agrees within 1%. The experiment consisted of 20 consecutive experiments. Data from these studies are reported in Table II.

The data for tests 1-3 listed in this table are 78/22) T, FC-13 Azeotrope-like formulations of 4a/HFC-152a outperform RFC-134a. shown to increase COP by 66% and give similar capacity to HFC-134a. There is. Additionally, the formulation has COP and COP comparable to that achieved with CFC-12. Give capacity. Compressor discharge pressure for the formulation was given for HFC-434a , eliminating the need to design air conditioners to withstand higher operating pressures.

Tests 4-G reduce airflow to the condenser to achieve greater discharge pressure and temperature. Represents more extreme conditions that result in severe symptoms. RFC-134a/HFC-152a combination The product has a 4% odor modified COP, and the capacity is slightly (2%) compared to RFC-1,34a. ) and also reduce the discharge pressure.

Table IT Performance discharge of HFC-124a/HFC-152a blend of 78/22 Akyem 1 note discharge accumulator work COP test 1: CFC-12 255, 260, 8174, 053, 25194, 72153, 42, 41 exam 2:RFC-134a 284.0 59.5 163.6 5 completed, 3 4948.8 2224.2 2.23 Test 3: HFC-134a/RFC-152a (78/22) 27 0.9 5? , 1. 171.2 52.3 5069.7 2128.6 2 ．． 38 Test 41 CFC-12 313,760,7187,’8! 53.1 3957.4 2332.8 1.70 Test 5: RFC-134a 352.7 59.6 111+(1,451,33538,92881,0! , 49 Test 6: RFC-134a/HFC-152a (78/22) 339 ．． 1 57.2 194.4 51.6 3603.1 2321.7 1.5 5 Having described the present invention in detail, reference to its preferred embodiments allows for modifications and Changes may be made without departing from the scope of the invention as defined in the appended claims. It is clear that there is.

Submission of translation of written amendment (Article 184-8 of the Patent Law) June 11, 1992 ″：’Fff!’″ R? Rm’la country 1 patent application display PCT/US 90106996 3. Patent applicant Name: Allied-Signal Incoho (Note Sodo 4 agent) 5 Submission date of written amendment Translation of replacement sheet (claims) Request to replace pages 12 to 13 of the original translation scope of request 1, 1. 1. 1. About 85 to about 95% by weight of 2-teI difluoroethane and 1,1-difluoroethane in an amount of about 5 to about 15% by weight, at a vapor pressure of 20°C. an azeotrope-like composition having a pressure of about 76 psia.

2. After condensing the composition according to claim 1, the area near the main body to be cooled. A method of providing cooling comprising evaporating said composition.

3. Condensing the composition according to claim 1 near the main body to be heated (7 times) A method of heating said composition comprising evaporating said composition.

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Claims (9)

[Claims] 1.1,1,1,2-tetrafluoroethane and 1,1-difluoroethane an azeotrope-like composition having a vapor pressure of about 76 psia ± 5 psia at 20° C. . 2.1,1,1,2-tetrafluoroethane and 1,1-difluoroethane Contains an amount effective for heat exchange applications, with a vapor pressure of approximately 76 psia ± 5 psia at 20°C. Certain azeotrope-like compositions. 3.1,1,1,2-tetrafluoroethane and 1,1-difluoroethane an azeotropic mixture consisting essentially of object-like composition. 4. About 5 to about 90% by weight of 1,1,1,2-tetrafluoroethane and 1,1 - Contains about 10 to about 95% by weight of difluoroethane and has a vapor pressure of about 76 ps at 20°C An azeotrope-like composition that is ia. 5. The composition may contain about 40 to about 85 1,1,1,2-tetrafluoroethane. % by weight and about 15 to about 60% by weight of 1,1-difluoroethane, and has a vapor pressure of 5. The azeotrope-like composition of claim 4, wherein the azeotrope-like composition is about 76 psia at 20<0>C. 6. About 5 to about 90% by weight of 1,1,1,2-tetrafluoroethane and 1,1- consisting essentially of about 10 to about 95% by weight difluoroethane, having a vapor pressure of about 20°C. Azeotrope-like composition that is 76 psia. 7. The composition may contain about 40 to about 85 1,1,1,2-tetrafluoroethane. % by weight and about 15 to about 60% by weight of 1,1-difluoroethane, and has a vapor pressure of 7. The azeotrope-like composition of claim 6, wherein the azeotrope-like composition is about 76 psia at 20<0>C. 8. After condensing the composition according to claim 1, the A method of effecting cooling comprising evaporating a composition of. 9. After condensing the composition according to claim 1 near the body to be heated, A method of heating the composition comprising evaporating the composition.