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
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
  • C11D7/50—Solvents
  • C11D7/5036—Azeotropic mixtures containing halogenated solvents
  • C11D7/504—Azeotropic mixtures containing halogenated solvents all solvents being halogenated hydrocarbons
  • C11D7/505—Mixtures of (hydro)fluorocarbons
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D2111/00—Cleaning compositions characterised by the objects to be cleaned; Cleaning compositions characterised by non-standard cleaning or washing processes
  • C11D2111/10—Objects to be cleaned
  • C11D2111/14—Hard surfaces
  • C11D2111/20—Industrial or commercial equipment, e.g. reactors, tubes or engines

Definitions

• the present invention relates to non-azeotrope, azeotrope, and azeotrope-like compositions. More specifically, this invention relates non-azeotrope, azeotrope, and azeotrope-like mixtures of hydrofluorocarbons and methods of using the same for removing contaminants from vapor compression systems.
• contaminants refers to processing fluids, lubricants, particulates, sludge, and/or other materials that are used in the manufacture of these systems or generated during their use.
• these contaminants comprise compounds such as alkylbenzenes, mineral oils, esters, polyalkyleneglycols, polyvinylethers and other compounds that are made primarily of carbon, hydrogen and oxygen.
• Vapor compression systems are used in a wide variety of applications such as heating and refrigeration. By compressing and expanding a heat transfer agent, such as a refrigerant, these systems are capable of absorbing and releasing heat according to the needs of a particular application.
• Common components of a vapor compression system include: vapor or gas compressors; liquid-cooled pumps; heat transfer equipment such as gas coolers, intercoolers, aftercoolers, heat exchangers, and economizers; vapor condensers such as reciprocating piston compressors, rotating screw compressors, centrifugal compressors, and scroll expanders; control valves and pressure-drop throttling devices such as capillaries; refrigerant-mixture separating chambers; steam-mixing chambers; connecting piping; and the like. These components are typically fabricated from copper, brass, steel, and the like, and have conventional gasket materials.
• Lubricants of a vapor compression system require lubrication to reduce friction caused by their relative physical contact and movements. These lubricants, which are compounds primarily composed of carbon, hydrogen, and oxygen, operate by coating the surfaces of component that are subjected to friction. Lubricants of a vapor compression system are typically mixed with the heat transfer agent which carries and disperses the lubricant throughout the system. However, during certain processes or procedures, it is desirable to remove these lubricants from the component surfaces, particularly during service operations. Such a need arises, for example, during the retrofitting of a chlorofluorocarbon (CFC) or hydrochlorofluorocarbon (HCFC) refrigerant-based system to a hydrofluorocarbon (HFC)-based system. There is also a need to remove processing lubricants during the manufacturing of a system. Failure to remove these types of contaminants from the system may lead to decreased efficiency or even to the failure of one or more components.
• CFC chlorofluorocarbon
• HCFC hydrochlor
• a vapor compression system may require cleaning after a catastrophic event, such as a compressor blowout.
• a catastrophic event such as a compressor blowout.
• This type of event can create contaminants, such as acids, sludge, and particulates, within the sealed system. Failure to remove these types of contaminants from the system may also lead to decreased efficiency or failure of one or more components.
• the aforementioned contaminants can typically be removed by flushing the vapor compression system with a flushing agent in which the contaminants are soluble or miscible.
• flushing agents contain one or more cleaning agents (for example, solvents for various types of hydrocarbons) and a propellant that carries the cleaning agent through the vapor compression system.
• the cleaning agent may also serve as the propellant.
• chlorofluorocarbons (CFC's) such as tricholormethane (R-11) and dichlorofluoroethane (R-141) were used as flushing agents for such systems. Although effective, CFC's are now considered environmentally unacceptable because of their contribution to the depletion of the stratospheric ozone layer. As the use of CFC's is reduced and ultimately phased out, new flushing agents are needed that not only perform well, but also pose no danger to the ozone layer.
• terpenes and low viscosity esters are known solvents of several types of lubricants commonly used in vapor compression systems, such as polyalkylene glycols, polyol esters, polyvinyl ethers, and the like.
• solvents have a boiling point above 100° C. and are difficult to remove from system components once they have been introduced during cleaning.
• Conventional techniques for removing these high boiling solvents prolongs the flushing operation which is economically disadvantageous.
• solvent remnants can have a deleterious effect on the performance of the vapor compression system.
• Certain embodiments of the present invention meet the aforementioned needs, among others, by providing novel non-azeotrope, azeotrope, and azeotrope-like compositions comprising HFC-mixtures of 1,1,1,2-tetrafluoroethane (HFC-134a) and one or more of 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,1,1,3,3-pentafluorobutane (HFC-365), and 1,1,1,2,2,3,4,5,5,5-decafluoropentane (HFC-43-10).
• HFC-134a 1,1,1,2-tetrafluoroethane
• HFC-245fa 1,1,1,3,3-pentafluoropropane
• HFC-365 1,1,1,3,3-pentafluorobutane
• HFC-43-10 1,1,1,2,2,3,4,5,5,5-decafluoropentane
• ⁇ refers to the amount of HFC-134a, that when combined with one or more of the other aforementioned components, results in the formation of an azeotrope or azeotrope-like composition.
• azeotrope-like refers to a combination of two or more compounds that behave substantially like a single compound in so far as the vapor in substantial equilibrium with the liquid has substantially the same concentration of components present in the liquid.
• azeotrope-like is intended to refer to both true azeotrope compositions and to compositions which are not strictly azeotropic, but in which the concentration of components in the vapor phase of the composition are so close to the concentration of components in the equilibrium liquid phase of the composition as to make separation of the components by ordinary distillation not practically possible. In essence, the admixture distills without substantially changing its composition. This is to be contrasted with non-azeotrope (or “zeotrope”) compositions wherein the liquid composition changes to a substantial degree during boiling or evaporation.
• Azeotropes-like compositions according to the present invention include absolute azeotropes (compositions in which azeotropic conditions are satisfied over all values of temperature (up to the critical stage)) or limited azeotropes (compositions in which azeotropic conditions are satisfied only in a certain temperature range).
• Azeotropes-like compositions according to the present invention also include homoazeotropes, wherein the composition exists in a single liquid phase, or heteroazeotropes, wherein the composition exists as two or more liquid phases.
• azeotrope-like compositions according to the present invention can be binary, ternary, quaternary, or quinary azeotropes depending on whether the composition is composed of 2, 3, 4, or 5 compounds, respectively.
• HFC-245fa, HFC-365, and HFC-43-10 can be used as flushing agents.
• a propellant may also be required.
• HFC-134a can serve as such a propellant.
• certain azeotrope-like compositions are formed by mixing an effective amount of HFC-134a with HFC-245fa, HFC-365, HFC 43-10, or some combination thereof.
• azeotrope-like nature of these compositions is useful when the composition is utilized as a flushing agent, as a heat transfer agent, as a blowing agent for foams, or as an aerosols because it allows for uniform condensation and vaporization to occur at a single temperature.
• azeotrope-like flushing composition can be recycled because of its constant composition ratio in both liquid and vapor states.
• azeotrope-like compositions according to the present invention may also be used in open-loop systems, such as flush guns, although non-azeotrope compositions are preferred.
• the preferred azeotrope-like compositions of the present invention have a number of attributes or properties that render them particularly effective as flushing agents for cleaning vapor compression systems.
• Many contaminants, including lubricants, that are commonly found in vapor compression systems are adequately miscible or soluble in the preferred azeotrope-like compositions of the present invention.
• the term “adequately miscible”, as used herein, refers to the azeotrope-like composition's ability to interact with a contaminant to form a solution, emulsion, suspension, or mixture under normal cleaning conditions in such a way that the contaminant can be effectively removed from the surface needing to be cleaned.
• lubricants include, but are not limited to, mineral oils, alkylbenzenes, polyvinylethers, polyalkylene glycols, and polyol ester oils.
• the preferred azeotrope-like compositions evaporate readily using conventional techniques known in the art such as flushing the system with an inert gas, pulling a vacuum on the system, and/or heating the system.
• Factors that affect evaporation include vapor pressure, the amount of heat that is applied, the heat conductivity of the liquid, the specific heat of the liquid, the latent heat of vaporization, surface tension, molecular weight, the rate at which the vapor is removed.
• the most appropriate method for removing the flushing agent for any given application is dependent upon the characteristics of the application involved and one skilled in the art could readily determine which method would be the most appropriate for each such application.
• each of HFC-245fa, HFC-134a, and HFC-43-10 are nonflammable as defined by ASTME681-94, and therefore azeotrope-like compositions made from mixtures of these materials are also non-flammable.
• other azeotrope-like composition according to the present invention such as certain azeotrope-like mixtures of HFC-365 and HFC134a, may also be non-flammable.
• non-flammable mixtures of the present invention are preferred because they are less dangerous and therefore easier to handle. How, it is understood that mixtures according to the present invention may also be flammable, and that in certain application, the flammability of these mixtures may be advantageous.
• the preferred azeotrope-like compositions of the present invention are generally compatible with the materials of vapor compression systems, including metals and sealants.
• the preferred azeotrope-like compositions of the present invention are environmentally acceptable and do not to contribute to the depletion of the earth's stratospheric ozone layer.
• Non-flammable, substantially constant boiling compositions can also be formed using ternary compositions that comprise HFC-134a and two of the other components.
• present invention also provides compositions that may also 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 provided that the compositions are essentially azeotrope-like and contain all of the essential components described herein.
• Preferred azeotrope-like compositions of the present invention include: suitable mixtures of HFC-245fa and HFC-134a having from about 1 to about 99 weight percent HFC-134a and from about 99 to about 1 weight percent HFC-245fa; suitable mixtures of HFC-134a and HFC-365 having from about 60 to about 99 weight percent HFC-134a and from about 1 to about 40 weight percent HFC-365; and suitable mixtures of HFC-134a and HFC-43-10 having from about 45 to about 99 weight percent HFC-134a and from about 1 to about 55 weight percent HFC43-10.
• compositions according to the present invention may include one or more components, such as additives, which may not form new azeotrope-like compositions.
• additives may be used in the present compositions in order to tailor the composition for a particular use.
• Inhibitors may also be added to the present compositions to inhibit decomposition, react with undesirable decomposition products, and/or prevent the corrosion of metal surfaces. Typically, up to about 2 percent of an inhibitor based on the total weight of the azeotrope-like composition may be used.
• HFC-134a Eighteen grams of HFC-134a were added to an ebulliometer at atmospheric pressure. It was determined that the compound boiled at about ⁇ 25° C. HFC-245fa was added to the ebulliometer in increments until there was 7.04 weight percent (wt. %) of HFC-245fa. Surprisingly, the boiling point remained at about ⁇ 25° C. to about ⁇ 26° C., indicating that an azeotrope-like composition had formed.
• a composition comprising 93 wt. % HFC-134a and 7 wt. % HFC-245fa was produced and then transferred into a cylinder having a dip tube.
• a flushing apparatus was assembled that included a cylinder to hold an initial charge of the azeotrope-like composition, a vaporizing expansion device, an oil separator, and a compressor.
• An article representing a typical vapor compression component, such as a condenser, was weighed and then soiled by depositing approximately 15 grams of polyalkylene glycol (PAG) oil onto its interior surface. The article was then attached to the dip leg of the cylinder containing the azeotrope-like composition so that it could be cleaned.
• PAG polyalkylene glycol
• the azeotrope-like composition while in liquid phase, was transferred from the cylinder and through the article. As it passed through the article, it contacted the soiled surface. As a result of this contact, the PAG oil was dissolved by the azeotrope-like composition, thereby removing it from the surface of the article. As the azeotrope-like composition and dissolved oil exited the article, they passed through the expansion device causing the liquid to evaporate. The resulting vapor was passed through an oil separator that removed the oil from the azeotrope-like composition. The azeotrope-like composition was then transferred to a compressor were it was transformed back to a liquid phase. The liquid azeotrope-like composition was then recycled through the article to further clean the article's surface.
• This example illustrates the formation of an azeotrope-like composition according to the present invention and the cleaning efficacy of that composition.
• a mixture of 10 wt. % of HFC-134a and 90 wt. % of HFC-245fa was formulated and utilized.
• Example 2 The procedure specified in Example 1 was followed to prepare the composition, except that a mixture of 10 wt. % of HFC-134a and 90 wt. % of HFC-245fa was formed. Surprisingly, this composition also exhibited azeotrope-like characteristics.
• Example 2 The cleaning efficacy of this composition was tested using the same procedure specified in Example 1. After this azeotrope-like composition had circulated through the article for 45 minutes, it was found that the substantially all of the PAG oil was removed from the article. The apparatus was turned off and the article was weighted and found to be approximately at its original weight. Thus, none of the azeotrope-like composition or PAG oil remained in the article.
• This example illustrates the cleaning efficacy of an azeotrope-like composition according to this invention when a flush gun apparatus is utilized.
• two pounds of a mixture of 20 wt. % of HFC-134a and 80 wt. % of HFC-245fa were formulated and then charged into a flush gun.
• the interior of an air conditioning condenser was soiled with 15 grams of PAG oil.
• the condenser is arranged so that the azeotrope-like composition can flow through it.
• the outlet of the condenser is connected to an evacuated recovery cylinder via a high pressure refrigeration hose.
• the recovery cylinder is cooled by dry ice.
• the inlet of the condenser is attached to the nozzle of the flush gun by a secure fitting and valve.
• the valve was opened to allow the azeotrope-like composition to flow from the flush gun through the condenser and ultimately into the recovery cylinder.
• the azeotrope-like composition passed through the condenser, it contacted the condenser's soiled surface.
• the PAG oil was dissolved by the azeotrope-like composition, thereby removing it from the surface of the condenser. If required, any excess HFC-245fa that became trapped in the condenser was removed by dry nitrogen or by passing pure HFC-134a through the condenser.
• This example illustrates the cleaning efficacy of an azeotrope-like composition according to this invention when a flush gun apparatus is utilized.
• a mixture of 20 wt. % of HFC-134a, 30 wt. % of HFC-365, and 50 wt. % of HFC-245fa was formulated and utilized.
• HFC-134a Approximately 18.97 grams of HFC-134a was added to an ebulliometer equipped with a vacuum jacket having a condenser on top and a quartz thermometer. HCF-365mfc is added in small increments. Temperature depression was observed when the HFC-365mfc is added, indicating a minimum boiling azeotrope. As shown in Table 1 below, the boiling point of this composition fluctuates only about 0.7° C. as the HFC134a: HFC-365mfc mixture changes from a weight ratio of 100:0 to a weight ratio of 65:35. TABLE 1 HFC134a: HFC365mfc Composition at 14.4 psia ⁇ from 100% HFC Wt. % HFC 365 mfc Wt.
• HFC-134a Approximately 19.86 grams of HFC-134a was added to the ebulliometer described in Example 5. HCF-43-10 is added in small increments. Temperature depression was observed when the HCF-43-10 is added, indicating a minimum boiling azeotrope. As shown in Table 2 below, the boiling point of this composition fluctuates only about 0.7° C. as the HFC134a: HCF-43-10 mixture changes from a weight ratio of 100:0 to a weight ratio of 45:55. TABLE 2 HFC134a: HFC-43-10 Composition at 14.4 psia T Wt. % HFC-43-10 Wt.

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• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
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• Combustion & Propulsion (AREA)
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• Detergent Compositions (AREA)
• Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
• Cleaning By Liquid Or Steam (AREA)

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• 2005
  • 2005-02-16 US US11/059,485 patent/US20060179852A1/en not_active Abandoned
• 2006
  • 2006-02-13 WO PCT/US2006/004908 patent/WO2006088764A1/en not_active Ceased
  • 2006-02-13 CA CA002597914A patent/CA2597914A1/en not_active Abandoned
  • 2006-02-13 CN CNA2006800126412A patent/CN101160368A/zh active Pending
  • 2006-02-13 EP EP06734856A patent/EP1848785A1/en not_active Withdrawn
  • 2006-02-13 JP JP2007556221A patent/JP2008531768A/ja not_active Withdrawn
  • 2006-02-15 TW TW095105104A patent/TW200636059A/zh unknown

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