Background of the Invention
1. Field Of The Invention
Pure water is most commonly produced by distillation which is the oldest and well-known method. In practice, there are currently three different types of distillation systems, namely, standard thermal, multiple effect and vapor compression. All of these types purify by vaporizing a portion of the feed water thereby concentrating impurities in the remaining liquid and subsequently condensing the pure distillate. Often the vapor phase is further purified by filtration or baffling devices that eliminate particles, such as pyrogens, that may be carried over during the vaporization. To maintain the high level of purity, piping and components that are wetted by the vapor or condensate are fabricated from stainless steel or similar non-corrosive materials.
The thermal still is the simplest form. Feed water is passed through a heat exchanger that may be heated by steam or electrical resistance elements. It is brought to boiling and the vapor is then condensed in a second heat exchanger that is usually water cooled. While this is a very simple process there is an inherent and significant lack of efficiency.
Multiple effect stills provide multi-stage variations of the standard still that operate with greater efficiency. For example high pressure steam is used to vaporize feed water in the first stage of such a still. Vapor generated in the first stage is then condensed in a second heat exchanger. Heat released in this phase change is used to vaporize additional feed water. Theoretically given sufficient high steam supply pressure, any number of stages can be so arranged, each producing the same amount of distillate from essentially the same single quantity of latent heat. In practice typical designs incorporate four or five stages. While efficient, multiple effect stills are expensive and require pressure vessels and a reliable supply of high pressure steam.
The vapor compression still utilizes a mechanical compressor to increase the heat energy of the pure water vapor so that the latent heat of condensation can be transferred to the vaporizing feed water through a heat exchanger. Because this latent heat vaporization is recovered, this is a highly efficient system. Further high pressure equipment is not required. On the other hand the mechanical compressor which is most usually constructed from stainless steel is rather expensive and is subject to maintenance problems and contamination problems.
The present invention offers a high level of energy efficiency and yet does not require high pressures, special seals or a mechanical compressor for water vapor compression. The present system incorporates a very high temperature refrigeration circuit to transfer heat release during condensation of the distillate to the feed water.
2. Description Of The Prior Art
Various prior art devices have been utilized to provide high efficiency distillation systems, some utilizing refrigeration or heat pumping systems coordinated therewith such as U.S. Pat. No. 2,619,453 issued Nov. 25, 1952 to R. Andersen on a Vapor-Compression Distillation; U.S. Pat. No. 2,921,004 issued Jan. 12, 1960 to L. Wood on an Apparatus For The Evaporation Or Distillation Of Water; U.S. Pat. No. 3,203,875 issued to H. Sturtevant on Aug. 31, 1965 for an Apparatus For Distilling Water With Waste Heat; U.S. Pat. No. 3,226,306 issued to J. Hausner on Dec. 28, 1965 for a Rotary Film Distillation And Gas Refrigerant Condensing Apparatus; U.S. Pat. No. 3,234,109 issued to E. Lustenader on Feb. 8, 1966 on a Method And Apparatus For Flash Distillation; U.S. Pat. No. 3,299,649 issued to W. McGrath et al on Jan. 24, 1967 for Separation Systems; U.S. Pat. No. 3,404,537 issued to J. Leonard, Jr. on Oct. 8, 1968 for a Combined Refrigeration And Saline Water Conversion System; U.S. Pat. No. 3,461,041 issued to T. Snyder on Aug. 12, 1969 for Vapor Compression Distillation Of Chemically Treated Degassed Saline Water; U.S. Pat. No. 3,461,460 issued to W. McGrath on Aug. 12, 1969 for Flash Distillation With Condensed Refrigerant As Heat Exchanger; U.S. Pat. No. 3,486,985 issued to W. McGrath on Dec. 30, 1969 for Flash Distillation Apparatus With Refrigerant Heat Exchange Circuits; U.S. Pat. No. 3,492,205 issued t. R. Webber on Jan. 27, 1970 for a Distillation System And Method; U.S. Pat. No. 3,522,149 issued to J. Arvan on Jul. 28, 1970 for a Distillation Apparatus To Recover Potable Water From Non-Potable Water; U.S. Pat. No. 4,014,751 issued to J. McCord on Mar. 29, 1977 for a Vapor Generating And Recovering Apparatus; U.S. Pat. No. 4,181,577 issued to N. Foley on Jan. 1, 1980 for a Refrigeration Type Water Desalinization Units; U.S. Pat. No. 4,214,454 issued Jul. 29, 1980 to J. Taylor on a Water Recovery System; U.S. Pat. No. 4,248,056 issued Feb. 3, 1981 to W. Beacham on a Heat Reclaimer For A Heat Pump; U.S. Pat. No. 4,267,022 issued May 12, 1981 to F. Pitcher on an Energy Efficient Process And Apparatus For Desalinizing Water; U.S. Pat. No. 4,278,502 issued to C. Stevens et al on Jul. 14, 1981 for a Chemical Recovery Apparatus; U.S. Pat. No. 4,345,971 issued Aug. 24, 1982 to W. Watson on a Distillation Employing Heat Pump; U.S. Pat. No. 4,390,396 issued to H. Koblenzer on Jun 28, 1983 for an Apparatus For The Distillation of Vaporizable Liquids; U.S. Pat. No. 4,463,575 issued to J. McCord on Aug. 7, 1984 for Vapor Generating And Recovery Apparatus Including A Refrigerant System With Refrigerant Heat Removal Means; U.S. Pat. No. 4,678,587 issued Jul. 7, 1987 to J. Voinche et al on a Water Distillation Method; U.S. Pat. No. 4,770,748 issued to J. Cellini et al on Sep. 13, 1988 for a Vacuum Distillation System and U.S. Pat. No. 4,955,207 issued Sep. 11, 1990 to C. Mink on a Combination Hot Water Heater-Refrigeration Assembly.
Summary of the Invention
The present invention provides a high efficiency water distillation process and apparatus including a heat pump process and system wherein the heat pump apparatus includes refrigerant passing through a refrigerant conduit. A liquid receiver is defined for accumulating the refrigerant therein in liquid form.
The heat pumping system further includes an expansion valve operatively connected with respect to the refrigerant conduit for receiving refrigerant from the liquid receiver. A refrigerant evaporator is operatively connected with respect to the refrigerant conduit for receiving refrigerant from the expansion valve. A compressor is operatively connected with respect to the refrigerant conduit for compressing the refrigerant vapor received from the refrigerant evaporator. An evaporator pressure regulator may be included positioned within the refrigerant conduit between the refrigerant evaporating device and the compressor to restrict the evaporation of the refrigerant such that it occurs at approximately 180 degrees Fahrenheit.
A refrigerant condensing device is adapted to receive the compressed refrigerant vapor from the compressor for condensing thereof into liquid phase at approximately 225 degrees Fahrenheit to facilitate accumulation of refrigerant within the liquid receiver. A sight glass may be positioned within the refrigerant conduit between the liquid receiver and the expansion valve to facilitate external viewing of operation of the system. Furthermore a filter dryer may be positioned within the refrigerant conduit between the liquid receiver and the expansion valve for processing of refrigerant passing therethrough. Additionally an oil separator may be positioned within the refrigerant conduit as required.
The water distillation device for use with the heat pumping apparatus may preferably include a feed water supply line defining an inlet therein adapted to receive feed water at approximately 70 degrees Fahrenheit. The water pre-heating device may be positioned within the feed water supply line or the water evaporator and is adapted to heat the feed water passing therethrough to a approximately 150 degrees Fahrenheit. A water evaporator is adapted to receive water through the feed water supply line from the water pre-heating means. The water evaporator is operative at a level of at least one atmospheric barometric pressure and is operatively positioned in thermal communication with respect to the refrigerant condenser to receive heat therefrom for vaporization of the feed water after pre-heating thereof and while passing through the water evaporator. The water evaporator heats the water to at least its saturation temperature, nominally 212 degrees Fahrenheit, to achieve the vaporization thereof by actual boiling.
The primary contaminant removal device is positioned adjacent the water evaporator and is adapted to remove contaminants accumulated by the evaporator and impurities accumulated by the evaporator for removal. Preferably the primary contaminant removal means comprises a blow down removal means. A secondary contaminant removal means is adapted to receive the vaporized feed water from the water evaporator for removal of contaminants. This secondary contaminant removal means preferably comprises a baffle device providing a plurality of surfaces which induce directional and velocity changes over which the water vapor therein passes to remove particulate contaminants and minute water droplets therefrom. This secondary contaminant removal means is adapted to supply purified water vapor to the water condensing device.
A heat reclaiming device may be positioned within the feed water supply line between the inlet end thereof and the water pre-heating device. The heat reclaiming device is in thermal communication with respect to the primary and secondary contaminant removal means to recycle heat from the materials removed by these two contaminant removal means to the incoming feed water. In this manner reclaiming of this heat will provide significant economizing measures and minimize the amount of heating and thus energy required by the pre-heater.
A water condenser is adapted to receive the vaporized and purified water from the contaminant removal device. The water condenser is operatively positioned in thermal communication with respect to the refrigerant evaporator to be cooled therefrom to facilitate condensation of vaporized feed water within the water condenser means at approximately 180 degrees Fahrenheit. A water exit line is in fluid flow communication with respect to the water condenser to receive the high quality distilled water therefrom for usages thereof as desired.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein hot water distillate of such high quality is produced as to be usable within the pharmaceutical industry.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein vaporization of water within the water evaporator is achieved by boiling above atmospheric pressure.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein a pre-heater is included to help raise the operating temperature of the system in order to facilitate vaporization within the water evaporator by boiling above atmospheric pressure.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein heat is reclaimed from contaminant and condensate droplet removal.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein the latent heat of the distillate is reclaimed by the evaporating refrigerant.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein water vapor is condensed at approximately 180 degrees Fahrenheit.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein the water evaporator produces pure water vapor at approximately 215 degrees Fahrenheit.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein high pressure requirements are minimized and special seals are not required to facilitate system operation and which facilitates a very sanitary construction.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein initial capital outlay is minimized.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein maintenance requirements and costs are minimized.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein a great variety of different types and classes of refrigerants are usable.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein the latent heat of the purified water is recovered by evaporation of refrigerant in the adjacently positioned heat pump system.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein energy is added to the system during the compression of the refrigerant vapors.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein contamination of the distillate is minimized.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein a depyrogenating baffle removes contaminants and minute distillate particles from the pure water vapor.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein contaminants are removed from the water evaporator by continuous blow down purge with heat reclaiming thereof.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein water vaporization is achieved at approximately 220 degrees Fahrenheit to facilitate disinfection thereof.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein the heat pump system includes a thermal-expansion valve which can reduce refrigerant pressure to approximately 65 psi corresponding to a saturation temperature of 180 degrees Fahrenheit.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein the heat pump system includes a compressor for achieving a nominal 125 psi with the corresponding saturation temperature of 225 degrees Fahrenheit.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein vaporization of water is achieved by boiling rather than a flash distillation process at reduced pressure.
It is an object of the present invention to provide an improved highly efficient water distillation process and apparatus for use with a heat pump system wherein condensing of the water is achieved at approximately 180 degrees Fahrenheit.
Brief Description of the Drawing
While the invention is particularly pointed out and distinctly claimed in the concluding portions herein, a preferred embodiment is set forth in the following detailed description which may be best understood when read in connection with the accompanying drawing, in which the FIGURE illustrates a schematic representation of an embodiment of a high efficiency water distillation process and apparatus using a heat pump system of the present invention.
Detailed Description of the Preferred Embodiment
The present invention provides a high efficiency water distillation apparatus and process for use thereof using a heat pumping apparatus 10 which includes refrigerant 12 circulating through refrigerant conduit means 14. Liquid refrigerant is accumulated within the liquid receiver means 16. The liquid refrigerant 12 within conduit 14 may then be carried through a sight glass 28 to facilitate inspection thereof and through a filter dryer 30. An expansion valve 18 is subsequently positioned within the refrigerant conduit 14 to reduce the pressure thereof. Refrigerant 12 is then vaporized in the refrigerant evaporator means 20. This vaporized refrigerant is then compressed by way of compressor means 22.
A pressure regulator 24 may be positioned within the refrigerant conduit 14 between the refrigerant evaporator means 20 and the compressor means 22. Evaporator pressure regulator 24 will control the pressure within the refrigerant evaporator 20 to facilitate refrigerant vaporization at a predetermined temperature.
The compressed refrigerant vapor 12 will pass from the compressor means 22 to the refrigerant condensing means 26 wherein it will be condensed and cooled to give up the latent heat to facilitate boiling of the feed water. The heat pumping apparatus 10 can include an oil separator means 32 positioned adjacent the compressor means 22.
The water distillation means 34 of the present invention includes a feed water supply line means 36 which may include an inlet end 38 for admitting feed water therein at a temperature of approximately 70 degrees Fahrenheit. The feed water will pass through a water pre-heating means 40 which is designed to elevate the water temperature to a level between 100 and 200 degrees Fahrenheit preferably in the area of 150 degrees Fahrenheit.
The pre-warmed feed water will then pass into a water evaporator means 42 positioned in thermal communication with respect to the refrigerant condensing means 26. At a pressure of approximately one atmosphere the water will be boiled and the temperature of the water vapor exiting will be increased to approximately 220 degrees Fahrenheit.
A primary contaminant removal means 44 such as a blow down removal means 46 will be operatively connected with respect to the water evaporator means 42 to remove contaminants therefrom. A secondary contaminant removal means 48 such as a baffle means 50 will be adapted to remove particles and condensate droplets from the distilled vapor after it has exited the water evaporator means 42. The pure water vapor now at 220 degrees Fahrenheit will pass directly to the water condensing means 54 positioned immediately adjacent the refrigerant evaporator means 20 such that the latent heat of the distillate can be reclaimed by water condensation within water condensing means 54 simultaneously with refrigerant vaporization within the refrigerant evaporating means 20. The condensed high quality pure water have a temperature thereof of approximately 180 degrees Fahrenheit will then exit through the water exit line 56.
It is desirable to reclaim the heat of contaminants removed from the water distillation means 34. For this purpose a heat reclaiming means 52 will be positioned within the feed water supply line means 36 upstream from the water pre-heating means 40. Heat reclaiming means 52 will be in thermal communication with respect to both the primary contaminant removal means 44 and the secondary contaminant removal means 48 in order to remove the heat thereof to facilitate economizing of operation of the water pre-heating means 40.
The simultaneous operation of the heat pumping apparatus 10 and the water distillation means 34 is best shown by viewing the figure of the present invention. The main water supply line 36 is shown in darker outline to facilitate analysis of the figure. As shown in that drawing, feed water is brought in through the feed water supply line means 36 and passes through the heat reclaiming means 52 wherein heat from the system blow down is recovered. The blow down is needed to prevent impurities from becoming too highly concentrated. The blow down removal means 46 is a continuous removal of contaminants from the water evaporator means 42.
The feed water then passes through the water pre-heating means 40 where its sensible heat and temperature are increased. The feed water is boiled in the water evaporator means 42 where the heat source is the refrigerant condensing within the coils of the refrigerant condensing means 26. This condensation occurs at a temperature above 212 degrees Fahrenheit. The distillate vapor is then passed through a baffle means 50 that utilizes flow kinetics to separate particles such a pyrogens and/or minute droplets of condensate from the water vapor. This pure water vapor is then condensed at approximately 180 degrees Fahrenheit in the water condensing means 54 where its latent heat is transferred to the evaporating refrigerant 12 of refrigerant evaporator means 20.
The elevated condensing temperature is desirable in order to insure maintenance of disinfection. Furthermore this elevated temperature constrains the entire thermodynamic cycle to run at higher temperatures and corresponding pressures above atmosphere.
Within the heat pumping apparatus 10 the expansion valve means 18 is preferably adapted to reduce the pressure of the refrigerant 12 to approximately 65 psi which for trichloromonofluoromethane corresponds to a saturation temperature of 180 degrees Fahrenheit. Subsequent thereto the refrigerant is vaporized in the refrigerant evaporator means 20 which is positioned adjacent the water condensing means 54 to be in thermodynamic communication therewith. In this manner the latent heat of the distillate will be absorbed and reclaimed. The refrigerant will then pass through an evaporator pressure regulator 24 which will be adjusted to maintain the pressure within the refrigerant evaporator means 20 as desired.
The refrigerant vapor is then compressed by compressor means 22 to a nominal 125 psi with a corresponding saturation temperature of 220 degrees Fahrenheit. The super-heated vapor may then passed through an oil separator 32 and returned to the refrigerant condensing means 26 positioned adjacent the water evaporator means 42 where it is cooled and condensed again giving up its latent heat to boil the water within the water evaporator means 42.
As such the total heat available for heating and boiling includes latent heat of condensation and the heat of compression of the refrigerant gas. For most applications this total heat will not be quite sufficient to permit operation at the desired temperature and must be supplemented by the water pre-heating means 40.
While particular embodiments of this invention have been shown in the drawings and described above, it will be apparent, that many changes may be made in the form, arrangement and positioning of the various elements of the apparatus and process. In consideration thereof it should be understood that preferred embodiments of this invention disclosed herein are intended to be illustrative only and not intended to limit the scope of the invention.