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WO1991009089A1 - Compositions de type azeotrope de 1,1,1,2-tetrafluoroethane et de 1,1-difluoroethane - Google Patents

Compositions de type azeotrope de 1,1,1,2-tetrafluoroethane et de 1,1-difluoroethane Download PDF

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Publication number
WO1991009089A1
WO1991009089A1 PCT/US1990/006996 US9006996W WO9109089A1 WO 1991009089 A1 WO1991009089 A1 WO 1991009089A1 US 9006996 W US9006996 W US 9006996W WO 9109089 A1 WO9109089 A1 WO 9109089A1
Authority
WO
WIPO (PCT)
Prior art keywords
azeotrope
compositions
hfc
psia
tetrafluoroethane
Prior art date
Application number
PCT/US1990/006996
Other languages
English (en)
Inventor
Gary M. Knopeck
Earl A. E. Lund
Fun Y. Ng
S. Robert Orfeo
David P. Wilson
Original Assignee
Allied-Signal Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Allied-Signal Inc. filed Critical Allied-Signal Inc.
Priority to KR1019920701381A priority Critical patent/KR0143547B1/ko
Publication of WO1991009089A1 publication Critical patent/WO1991009089A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
    • C09K5/02—Materials undergoing a change of physical state when used
    • C09K5/04—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa
    • C09K5/041—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa for compression-type refrigeration systems
    • C09K5/044—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa for compression-type refrigeration systems comprising halogenated compounds
    • C09K5/045—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa for compression-type refrigeration systems comprising halogenated compounds containing only fluorine as halogen
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K2205/00—Aspects relating to compounds used in compression type refrigeration systems
    • C09K2205/22—All components of a mixture being fluoro compounds

Definitions

  • This invention relates to azeotrope-like compositions of 1,1,1,2-tetrafluoroethane and 1.1-difluoroethane. These mixtures are useful as refrigerants for heating and cooling applications.
  • Fluorocarbon based fluids have found widespread use in industry for refrigeration, air conditioning and heat pump applications.
  • Vapor compression is one form of refrigeration.
  • vapor compression involves changing the refrigerant from the liquid to the vapor phase through heat absorption at a low pressure and then from the vapor to the liquid phase through heat removal at an elevated pressure.
  • the refrigerant is vaporized in the evaporator which is in contact with the body to be cooled.
  • the pressure in the evaporator is such that the boiling point of the refrigerant is below the temperature of the body to be cooled.
  • the vapor formed is then removed by means of a compressor in order to maintain the low pressure in the evaporator.
  • the temperature and pressure of the vapor are then raised through the addition of mechanical energy by the compressor.
  • the high pressure vapor then passes to the condenser whereupon heat exchanges with a cooler medium.
  • the sensible and latent heats are removed with subsequent condensation.
  • the hot liquid refrigerant then passes to the expansion valve and is ready to cycle again.
  • While the primary purpose of refrigeration is to remove energy at low temperature, the primary purpose of a heat pump is to add energy at higher temperature.
  • Heat pumps are considered reverse cycle systems because for heating, the operation of the condenser is interchanged with that of the refrigeration evaporator.
  • Certain chlorofluorocarbons have gained widespread use in refrigeration applications including air conditioning and heat pump applications owing to their unique combination of chemical and physical properties.
  • the majority of refrigerants utilized in vapor compression systems are either single component fluids or azeotropic mixtures. Single component fluids and azeotropic mixtures are characterized as constant-boiling because they exhibit isothermal and isobaric evaporation and condensation.
  • the use of azeotropic mixtures as refrigerants is known in the art. See. for example. R.C. Downing, "Fluorocarbon Refrigerants Handbook", pp. 139-158. Prentice-Hall. 1988. and U.S. Patents 2.101.993 and 2.641.579.
  • Azeotropic or azeotrope-like compositions are desired because they do not fractionate upon boiling or evaporation. This behavior is desirable because in the previously described vapor compression equipment with which these refrigerants are employed, condensed material is generated in preparation for cooling or for heating purposes, and unless the refrigerant composition is constant boiling, i.e. is azeotrope- like. fractionation and segregation will occur upon evaporation and condensation and undesirable refrigerant distribution may act to upset the cooling or heating.
  • Non-azeotropic mixtures have been disclosed as refrigerants, see. e.g.. U.S. Patent 4,303.536. but have not found widespread use in commercial applications even though the ability of non-azeotropic refrigerant blends to exhibit improved thermodynamic performance has often been discussed in the literature. See, e.g., T. Atwood. "NARBS - The Promise and the Problem", American Society of Mechanical Engineers. Winter Annual Meeting, paper 86-WA/HT-61. 1986 and M.O. McLinden et al., "Methods for Comparing the Performance of Pure and Mixed Refrigerants in the Vapor Compression Cycle", Int. J. Refriq. 10, 318 (1987).
  • non-azeotropic mixtures may fractionate during the refrigeration cycle, they require certain hardware changes.
  • the added difficulty in changing and servicing refrigeration equipment is the primary reason that non-azeotropic mixtures have been avoided.
  • the situation is further complicated if an inadvertent leak in the system occurs during such use or service.
  • the composition of the mixture could change, affecting system pressures and system performance.
  • fractionation could shift the composition into the flammable region with potentially adverse consequences.
  • the substitute materials must also possess those properties unique to the CFC's including chemical stability, low toxicity, non-flammability. and efficiency in-use. The latter characteristic is important, for example, in refrigeration applications like air conditioning where a loss in refrigerant thermodynamic performance or energy efficiency may produce secondary environmental effects due to increased fossil fuel usage arising from an increased demand for electrical energy. Furthermore, the ideal CFC refrigerant substitute would not require major engineering changes to conventional vapor compression technology currently used with CFC refrigerants.
  • Another object of the invention is to provide novel environmentally acceptable refrigerants for use in the aforementioned applications.
  • the invention relates to novel environmentally acceptable azeotrope-like compositions of 1,1.1,2-tetrafluoroethane and 1.1-difluoroethane which are useful in heating and refrigeration applications.
  • novel azeotrope-like compositions comprising 1.1.1.2-tetrafluoroethane and 1,1-difluoroethane.
  • the azeotrope-like compositions comprise from about 5 to about 90 weight percent 1,1.1,2-tetrafluoroethane and from about 10 to about 95 weight percent 1,1-difluoroethane and have a vapor pressure of about 76 psia ⁇ 5 psia at 20°C.
  • These compositions are azeotrope-like because they exhibit essentially constant vapor pressure versus composition and essentially identical liquid and vapor compositions over the aforementioned ranges.
  • such azeotrope-like compositions comprise from about 40 to about 85 weight percent 1.1,1.2-tetrafluoroethane and from about 15 to about 60 weight percent 1.1- difluoroethane and have a vapor pressure of 76 psia + 3 psia at 20°C.
  • Vapor phase compositions containing in excess of about 80 weight percent 1.1.1.2-tetrafluoroethane were determined to be nonflammable in air at ambient conditions using the Bureau of Mines - style eudiometer apparatus.
  • the azeotrope-like compositions of this invention comprised of HFC-152a and HFC 134a, do not segregate. In addition, they exhibit a number of advantages over dichlorodifluoromethane (CFC-12), HFC-134. and HFC-152a.
  • CFC-12 dichlorodifluoromethane
  • HFC-134 HFC-134a
  • HFC-152a HFC-152a
  • the azeotrope-like mixtures are non-flammable above 80 weight percent HFC-134a thereby reducing the hazard of explosion which might occur if flammable HFC-152a vapors were used, stored, or handled in pure form.
  • azeotrope-like mixtures also exhibit zero ozone depletion potential and low atmospheric lifetime hence they contribute negligibly to the greenhouse warming effect. This is contrasted with the high ozone depletion potential and correspondingly high greenhouse warming potential of CFC-12. . . .
  • the energy efficiency and cooling capacity of the azeotrope-like compositions of the invention are superior to those of pure HFC-134a and. in addition, the 134a/152a compositions provide significantly reduced direct and indirect greenhouse warming potential over pure HFC-134a.
  • the azeotropic compositions of this invention uniquely possess all of the desireable features of an ideal refrigerant i.e.. safe to use, non-flammable, zero ozone depletion potential, negligible greenhouse warming effect, and attractive energy/cooling performance compared to the most relevant pure fluoromethane or fluoroethane fluids; i.e.. fluorocarbon refrigerants boiling between -19 C and o . . .
  • HFC-152a/HFC-134a are combined in effective amounts, a non-flammable, non-segregating, environmentally acceptable azeotrope-like refrigerant having improved thermodynamic performance results.
  • 1.1.1.2-tetrafluoethane and 1.1-difluoroethane are constant boiling or essentially constant boiling. All compositions within the indicated ranges, as well as certain compositions outside the indicated ranges, are azeotrope-like, as defined more particularly below.
  • thermodynamic state of a fluid is defined by four variables: pressure, temperature, liquid composition, and vapor composition, or P-T-X-Y, respectively.
  • An azeotrope is a unique characteristic of a system of two or more components where X and Y are equal at a stated P and T. In practice this means that the components cannot be separated during a phase change, and therefore are useful in the cooling and heating applications described above. . . .
  • azeotrope-like composition is intended to mean that the composition behaves like a true azeotrope in terms of this constant boiling characteristics or tendency not to fractionate upon boiling or evaporation.
  • the composition of the vapor formed during the evaporation is identical or substantially identical to the original liquid composition.
  • the liquid composition if it changes at all. changes only slightly. This is contrasted with non-azeotrope-like compositions in which the liquid and vapor compositions change substantially during evaporation or condensation.
  • vapor and liquid phases have identical compositions, then it can be shown, on a rigorous thermodynamic basis, that the boiling point versus composition curve passes through an absolute maximum or an absolute minimum at this composition. If one of the two conditions, identical liquid and vapor compositions or a minimum or maximum boiling point, are shown to exist, then the system is an azeotrope, and the other condition must follow.
  • One way to determine whether a candidate mixture is azeotrope-like within the meaning of this invention, is to distill a sample thereof under conditions (i.e. resolution - number of plates) which would be expected to separate the mixture into its separate components. If the mixture is non-azeotrope or non-azeotrope-like. the mixture will fractionate, i.e..
  • azeotrope-like compositions there is a range of compositions containing the same components in varying proportions which are azeotrope- like. All such compositions are intended to be covered by the term azeotrope-like as used herein.
  • azeotrope-like As an example, it is well known that at different pressures the composition of a given azeotrope will vary at least slightly as does the boiling point of the composition.
  • an azeotrope of A and B represents a unique type of relationship but with a variable composition depending on the temperature and/or pressure. As is readily understood by persons skilled in the art. the boiling point of an azeotrope will vary with the pressure.
  • the azeotrope-like compositions of the invention may be used in a method for producing cooling which comprises condensing a refrigerant comprising the azeotrope-like compositions and thereafter evaporating the refrigerant in the vicinity of the body to be cooled.
  • the azeotrope-like compositions of the invention may be used in a method for producing heating which utilizes condensing a refrigerant in the vicinity of the body to be heated and thereafter evaporating the refrigerant.
  • heat exchange applications For purposes of this application, the process embodiments for producing cooling or heating, discussed above, will generally be referred to as heat exchange applications.
  • the 1.1.1.2-tetrafluoroethane and 1.1-difluoroethane components of the novel azeotrope-like compositions of the invention are known materials. Preferably they should be used in sufficiently high purity so as to avoid the introduction of adverse influences upon the constant boiling properties of the system.
  • compositions may include additional components so as to form new azeotrope-like compositions. Any such compositions are considered to be within the scope of the present invention as long as the compositions are essentially constant boiling and contain all the essential components described herein.
  • azeotrope-like compositions of the invention may include components which may not form new azeotrope-like compositions.
  • lubricants like those discussed in U.S. Patent 4,755.316 may be added without departing from the scope of the invention..
  • compositions of 1.1.1.2-tetrafluoroethane and 1.1-difluoroethane are azeotrope-like, i.e., exhibit essentially identical liquid and vapor compositions, and are constant boiling, i.e., exhibit essentially constant vapor pressure versus composition within this range.
  • the performance of a refrigerant at specific operating conditions can be measured by the coefficient of performance and the capacity of the refrigerant.
  • the coefficient of performance, COP is a universally accepted measure, especially useful in representing the relative thermodynamic efficiency of a refrigerant in a specific heating or cooling cycle involving evaporation
  • the performance of a 78/22 HFC-134a/HFC-152a by weight azeotrope-like blend was evaluated in a typical automotive air conditioning unit operated under controlled laboratory calorimeter conditions.
  • the compressor and condenser sections of the air conditioning cycle were maintained in a controlled environment of 100°F.
  • Thermocouples were used to measure the temperature of the air flowing to and from the condenser and the temperature of the refrigerant at the discharge and suction ports of the compressor as well as at the condenser outlet.
  • the compressor was operated at a constant speed of 1188 revolutions per minute with an electric motor.
  • a Watt-hour meter was used to determine the mechanical work input to the compressor.
  • Heat removal from the condenser environment was achieved using chilled water flowing at a measured flow rate to a cooling coil in the condenser room.
  • the capacity of the air conditioning system is determined by performing an energy balance over the condenser room.
  • the evaporator and expansion valve section of the air conditioning cycle were maintained at 100°F and 40* relative humidity.
  • Thermocouples were used to measure the temperatures of the refrigerant leaving the evaporator and leaving the accumulator.
  • Two sets of electrical heaters in the evaporator room were continuously adjusted to balance the heat removed by the evaporator.
  • CFC-12 is a fully halogenated chlorofluorocarbon which has been used widely in air conditioning and refrigeration applications. CFC-12 has been determined to be a contributor to the depletion of the Earth's stratospheric ozone layer. Each test consisted of at least two consecutive experiments where the measured
  • Tests 4-6 represents a more extreme condition where the air flow over the condenser has been reduced which results in greater discharge pressures and temperatures.
  • the HFC-134a/HFC-152a blend provides a 4* improvement in COP and a slight (2*) drop -14-
  • Discharge Accumulator Discharge Acccumulator Capacity Work COP (psia) (psia) CF) CF) (Watt) (Watt)

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Thermal Sciences (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Detergent Compositions (AREA)
  • Lubricants (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)

Abstract

Nouvelles compositions de type azéotrope de 1,1,1,2-tétrafluoroéthane et de 1,1-difluoroéthane qui sont utiles pour des applications concernant le chauffage et le refroidissement.
PCT/US1990/006996 1989-12-11 1990-11-30 Compositions de type azeotrope de 1,1,1,2-tetrafluoroethane et de 1,1-difluoroethane WO1991009089A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1019920701381A KR0143547B1 (ko) 1989-12-11 1990-11-30 1,1,1,2-테트라플루오로에탄과 1,1-디플루오로에탄의 공비성 조성물

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US44901189A 1989-12-11 1989-12-11
US449,011 1989-12-11

Publications (1)

Publication Number Publication Date
WO1991009089A1 true WO1991009089A1 (fr) 1991-06-27

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Application Number Title Priority Date Filing Date
PCT/US1990/006996 WO1991009089A1 (fr) 1989-12-11 1990-11-30 Compositions de type azeotrope de 1,1,1,2-tetrafluoroethane et de 1,1-difluoroethane

Country Status (6)

Country Link
EP (1) EP0505436A1 (fr)
JP (1) JPH05502468A (fr)
KR (1) KR0143547B1 (fr)
CA (1) CA2069509A1 (fr)
MX (1) MX174019B (fr)
WO (1) WO1991009089A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0483573A1 (fr) * 1990-10-19 1992-05-06 Daikin Industries, Limited Mélanges azéotropiques ou pseudo-azéotropiques et systèmes de refrigération ou de conditionnement d'air les utilisant comme fluides de travail
EP0526477A4 (fr) * 1990-04-25 1992-12-15 Du Pont Melanges d'halocarbones.
US5725791A (en) * 1991-03-28 1998-03-10 E. I. Du Pont De Nemours And Company Azeotropic and azeotrope-like compositions of 1,1,2,2-tetrafluoroethane

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4303536A (en) * 1980-12-29 1981-12-01 Allied Corporation Nonazeotropic refrigerant composition containing monachlorodifluoromethane, and method of use
EP0314978A1 (fr) * 1987-10-19 1989-05-10 Daikin Industries, Limited Réfrigérants

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4303536A (en) * 1980-12-29 1981-12-01 Allied Corporation Nonazeotropic refrigerant composition containing monachlorodifluoromethane, and method of use
EP0314978A1 (fr) * 1987-10-19 1989-05-10 Daikin Industries, Limited Réfrigérants

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Japanese Patent Office, Tokyo, Japan, file supplier Japs; & JP-A-63 308 084 (ASAHI GLASS K.K.), 15 December 1988 *
Japanese Patent Office, Tokyo, Japan, file supplier Japs; & JP-A-63308084 (ASAHI GLASS K.K.), 9 June 1987 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0526477A4 (fr) * 1990-04-25 1992-12-15 Du Pont Melanges d'halocarbones.
EP0483573A1 (fr) * 1990-10-19 1992-05-06 Daikin Industries, Limited Mélanges azéotropiques ou pseudo-azéotropiques et systèmes de refrigération ou de conditionnement d'air les utilisant comme fluides de travail
US5725791A (en) * 1991-03-28 1998-03-10 E. I. Du Pont De Nemours And Company Azeotropic and azeotrope-like compositions of 1,1,2,2-tetrafluoroethane

Also Published As

Publication number Publication date
CA2069509A1 (fr) 1991-06-12
KR0143547B1 (ko) 1998-07-01
JPH05502468A (ja) 1993-04-28
EP0505436A1 (fr) 1992-09-30
KR927003753A (ko) 1992-12-18
MX174019B (es) 1994-04-14

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