Method of Liquifying a gas

A method of liquefying a gas is disclosed and which includes the steps of pressurizing a liquid; mixing a reactant composition with the pressurized liquid to generate a high pressure gas; supplying the high pressure gas to an expansion engine which produces a gas having a reduced pressure and temperature, and which further generates a power and/or work output; coupling the expansion engine in fluid flowing relation relative to a refrigeration assembly, and wherein the gas having the reduced temperature is provided to the refrigeration assembly; and energizing and/or actuating the refrigeration assembly, at least in part, by supplying the power and/or work output generated by the expansion engine to the refrigeration assembly, the refrigeration assembly further reducing the temperature of the gas to liquefy same.

TECHNICAL FIELD

The present invention relates to a method of liquifying a gas, and more specifically to a method for generating hydrogen gas at high pressure and then later cooling the high pressure hydrogen gas to liquify same.

BACKGROUND OF THE INVENTION

The prior art is replete with numerous examples of references which discuss, in great detail, the advantages of utilizing hydrogen gas to replace fossil fuels in the production of energy, either by means of electrochemical devices such as fuel cells, or which further can be consumed in the internal combustion engines of various overland vehicles.

While the advantages of using fuels, such as hydrogen, to replace fossil fuel as a primary energy source are many, no single approach has emerged which will provide a convenient means whereby hydrogen can be economically liquified thereby rendering it more useful in the applications noted above. As a general matter, the current methods of producing liquid hydrogen have been viewed, by most investigators, as being expensive and very energy intensive. Consequently, hydrogen has not currently been embraced as a substitute fuel to replace the various hydrocarbon based fuels which are widely used in the marketplace.

In addition to the foregoing shortcomings, another impediment to the widespread adoption and use of hydrogen as an alternative or replacement fuel to various widely used hydrocarbon fuels relates to the lack of a hydrogen infrastructure which would permit a hydrogen fuel to be distributed at widely diverse geographical locations.

A method of liquifying a gas which addresses these and other perceived shortcomings in the prior art teachings and practices is the subject matter of the present application.

SUMMARY OF THE INVENTION

One aspect of the present invention is to provide a method of liquefying a gas, which includes pressurizing a liquid; mixing a reactant composition with the pressurized liquid to generate a high pressure gas; supplying the high pressure gas to an expansion engine which produces a gas having a reduced pressure and temperature, and which further generates a power output; coupling the expansion engine in fluid flowing relation relative to a refrigeration assembly, and wherein the gas having the reduced temperature is provided to the refrigeration assembly; and energizing the refrigeration assembly, at least in part, by supplying the power output generated by the expansion engine to the refrigeration assembly, the refrigeration assembly further reducing the temperature of the gas to liquefy same.

Another aspect of the present invention relates to a method of liquefying a gas which includes, providing a container; supplying a liquid to the container; coupling a charging pump in fluid flowing relation relative to the container to increase the pressure of the liquid within the container; providing a reactant compound and supplying the reactant compound to the liquid which is under pressure in the container, and wherein the reactant compound chemically reacts with the liquid to generate a high pressure gas; providing an expansion engine, and coupling the expansion engine in fluid receiving relation relative to the container to receive the high pressure gas, and wherein the expansion engine, upon receiving the high pressure gas, provides a resulting power output, and further provides a gas output having a reduced temperature and pressure; providing a refrigeration assembly, and coupling the expansion engine in fluid flowing relation relative to the refrigeration assembly, and wherein the gas output having the reduced temperature and pressure is supplied to the refrigeration assembly; and supplying the power output generated by the expansion engine to energize the refrigeration assembly, and wherein the refrigeration assembly, when energized, liquefies the gas having the reduced temperature and pressure, and which is delivered from the expansion engine.

Yet still another aspect of the present invention relates to a method of liquefying a gas which includes, providing a container having a volume; providing a source of water; providing a charging pump coupled in fluid flowing relation relative to the source of water, and with container, the charging pump supplying the source of water to the container and filling the volume thereof to a pressure of greater than about 150 pounds per square inch; providing a source of a chemical hydride; metering the source of the chemical hydride to the container, and wherein the source of chemical hydride chemically reacts with the water, under pressure, to produce a high pressure hydrogen gas which is enclosed within the container; providing an expansion engine and supplying the high pressure hydrogen gas enclosed within the container to the expansion engine, and wherein the expansion engine is operable to generate a power output while simultaneously reducing the pressure and the temperature of the hydrogen gas supplied by the container; providing a refrigeration assembly and supplying the hydrogen gas having a reduced temperature and pressure to the refrigeration assembly; supplying the power output generated by the expansion engine to the refrigeration assembly to energize the refrigeration assembly, and wherein the refrigeration assembly, when energized, reduces the temperature of the hydrogen gas so that it passes from a gaseous phase to a liquid phase; and supplying the liquid hydrogen to a container for storage.

These and other aspects of the present invention will be discussed in greater detail hereinafter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first described arrangement which is useful in practicing the methodology of the present invention is shown inFIG. 1. As seen therein, the methodology includes providing a container which is generally indicated by the numeral11. The container11is defined by a sidewall12, and further includes a top surface13, and a bottom surface14which are attached to the sidewall and which define an internal cavity15. First, second and third passageways or apertures20,21and22are formed through the sidewall12and couple the internal cavity15in fluid flowing relation relative to other assemblies which will be discussed hereinafter.

The method of producing a high pressure gas10of the present invention includes a step of supplying the container11with a liquid, and increasing the pressure of the liquid within the container. In this regard, and referring toFIG. 1, a charging pump30is provided and is coupled to the second passageway21by way of a conduit or other fluid passageway31. The charging pump30is coupled in fluid flowing relation relative to a source of a liquid32by way of a conduit or fluid passageway which is generally indicated by the numeral33. The charging pump supplies the fluid to the container and increases the liquid pressure within the container11to greater than about 150 pounds per square inch. The liquid may include a substantially homogenous solution such as water, or a solution including two or more compositions, including catalysts which would facilitate the production or generation of the high pressure gas.

As seen inFIG. 1, the method of producing a high pressure gas10of the present invention further includes the step of supplying a reactant composition40which may include a metal or metal hydride to the liquid32which is under pressure within the container11. The reactant composition40chemically reacts with the liquid32to produce a resulting high pressure gas41.

The source of the reactant composition40is coupled in fluid communication with container11by way of a passageway or conduit42which allows the movement of the reactant composition into the cavity15. For purposes of the present application, the high pressure gas41will be described hereinafter as high pressure hydrogen gas. It should be understood that the present teachings are not limited to the production of hydrogen gas, but may be applied to other useful gasses. A hydrogen dryer50is provided, and a conduit or other fluid passageway51couples the third passageway22in fluid flowing relation relative to the hydrogen dryer. The hydrogen dryer50is operable to remove any undesirable gaseous fluids such as water vapor which is mixed with the released high pressure hydrogen gas41. The hydrogen dryer is coupled in fluid flowing relation relative to a storage container60by way of a fluid passageway which is generally indicated by the numeral61. The storage container for the high pressure hydrogen gas41may take on various forms including single or multiple containers and may further be integrated with other processes. It should also be understood in certain arrangements, a hydrogen dryer may not be required. For example, if the high pressure hydrogen gas41will be later supplied to an assembly such as a proton exchange membrane fuel cell, it may be actually advantageous to have a gaseous liquid, such as water vapor, supplied with same. Such gaseous liquids such as water vapor would actually encourage the production of electricity in various proton exchange membrane fuel cell arrangements.

Referring now toFIG. 2, a greatly simplified view of a second arrangement for practicing the method of the present invention10is shown. To the extent that like assemblies are described, similar numbers will be utilized. The method for producing a high pressure gas10includes providing a container11which is operable to enclose a fluid32under pressure. Similar to that described withFIG. 1, the container has a sidewall12, and top and bottom surfaces13and14which are joined together to form a cavity15. First, second, third and fourth passageways20,21,22and23are formed through the sidewall12and couple the cavity15in fluid flowing relation relative to other assemblies which will be described hereinafter. As was the case withFIG. 1, a charging pump30is provided and is coupled, by way of a fluid passageway31to the cavity15. Still further, the method comprises supplying a source of a fluid32to the cavity15and increasing the pressure of the fluid enclosed within the container11by means of the charging pump30. In the arrangement as shown inFIG. 2, the method further includes rendering a reactant composition40substantially chemically non-reactive, as will be described below. The supply of the reactant compound40performs in a manner similar to that described inFIG. 1, that is when the reactant compound is combined with the liquid32which has been pumped to high pressure within the container11, it produces a high pressure hydrogen gas41. The supply of the reactant compound40which is substantially chemically non-reactive includes a step of enclosing the reactant composition40in a frangible substantially chemically non-reactive enclosure43. The usefulness of compositions within these types of enclosures are discussed in greater detail in U.S. Pat. Nos. 5,728,464 and 5,817,157, the teachings of which are incorporated herein. Therefore the supply of the reactant composition40includes a plurality of these frangible containers43. As further seen inFIG. 2, a second source of a fluid44is provided, and a fluid passageway or conduit45couples the second source of fluid44in fluid flowing relation relative to the first passageway20. The fluid passageway45provides a course of travel for the fluid stream46, which is also coupled in fluid flowing relation relative to the conduit or fluid passageway42. As illustrated, the frangible containers43are operable to move along the conduit or passageway42and travel along with the fluid stream46which is produced from the second source of fluid44. The fluid passageway45is coupled in fluid flowing relation relative to a valve assembly47. The valve assembly is operable to selectively remove a portion of the fluid stream46which contains some of the frangible containers43from the remaining fluid stream, and deliver the isolated portion of the fluid stream along with some of the frangible containers43to the cavity15of the container11. A valve assembly47is coupled in fluid flowing relation relative to an assembly48which is operable to fracture or otherwise split open the frangible containers43thereby releasing the reactant composition40which may include a metal or metal hydride to the source of liquid32which has been placed under pressure by the charging pump30. The release of this reactant compound40causes a chemical reaction which produces the high pressure hydrogen gas41which was discussed above. Similar to that earlier discussed with respect toFIG. 1, the assembly shown inFIG. 2includes a hydrogen dryer50for removing gaseous water vapor which may be mixed with the hydrogen gas41and a storage container60for receiving and storing the high pressure hydrogen gas41which is generated as a result of this methodology.FIG. 2further illustrates a by-product container which is generally indicated by the numeral70, and which is coupled by way of a fluid conduit or passageway71to the container11. A valve assembly72is provided, and is disposed in fluid metering relation along the fluid conduit71. The by-product container70is operable to selectively receive the resulting by-products produced as a result of chemical reaction when the valve assembly72is operated. For example, in the instance where, sodium hydride, or sodium borohydride are employed as the reactant compound40, the by-product container70would be operable to receive the by-products of a chemical reaction which may include sodium hydroxide or sodium borate. The by-products may also include the remains of the frangible containers43which have been fractured by the assembly48.

Referring now toFIG. 3, a greatly simplified view of a third arrangement which can be utilized to practice the method of the present invention is shown.FIG. 3shows many of the features ofFIGS. 1 and 2. As was discussed with respect toFIG. 2, similar numbers indicate similar assemblies. As seen inFIG. 3, a container11defining a cavity15for enclosing a liquid32which has been placed under pressure by a charging pump30is provided. InFIG. 3it will also be seen that a source of reactant compound40(such as a metal or metal hydride) is provided and is coupled by way of a conduit42in dispensing relation relative to a fluid passageway45similar to that shown inFIG. 2. A second source of a fluid44is shown coupled in fluid flowing relation relative to the passageway45, the source of the second fluid is substantially inert and forms the fluid stream46which is subsequently mixed with the source of the reactant compound40which is supplied by way of the passageway42to the passageway45. The mixture of the inert fluid44, and the reactant compound40is supplied to an assembly49, here illustrated as a continuous screw or auger, and which is operable to supply the mixture of the inert fluid44and the reactant compound42to the chamber15. Once the reactant compound and the inert fluid is received in the chamber15, the reactant compound40chemically reacts with the fluid32in order to produce the high pressure hydrogen gas41. Similar to that shown withFIGS. 1 and 2, the high pressure hydrogen gas is subsequently supplied to a hydrogen dryer50by way of a conduit51, and then is provided to a storage container60. As was discussed withFIG. 1, the hydrogen dryer may be omitted under certain circumstances.

Referring now toFIGS. 1,2and3, the method of liquifying a gas10of the present invention, as earlier discussed includes the steps of pressurizing a liquid32within the container11and mixing a reactant composition40(which may comprise a metal or metal hydride) with the pressurized liquid to generate a high pressure gas41which may have a preponderance of hydrogen. As seen inFIGS. 1,2and3, the high pressure gas41, following treatment by the hydrogen dryer50, is delivered to an expansion engine which is indicated by the numeral60. The expansion engine is coupled in fluid flowing relation relative to the hydrogen dryer50by way of the conduit or fluid passageway61. Expansion engines are well known in the art and include internal turbines (not shown) and which when exposed to the flow of high pressure hydrogen gas41, produces a first mechanical output62, and a second gas output63having a reduced pressure and temperature. The mechanical output of the expansion engine is converted into various power or work outputs which may include, but are not limited to, mechanical, electrical, hydraulic or others and which are transmitted by way of a transmission pathway or other force or work transmission means64to a refrigeration assembly which is generally indicated by the numeral80. The refrigeration assembly80is of conventional design, and is coupled in fluid flowing relation relative to the gas output63of the expansion engine60and by way of a fluid conduit or passageway81. The refrigeration assembly80is coupled, by way of the transmission pathway or other force or work transmission means64, to the expansion engine60. The expansion engine is operable to generate, at least in part, the power or work output necessary to energize or actuate the refrigeration assembly80. The gas output63of the expansion engine60, once received by the refrigeration assembly80, is further reduced in temperature thereby liquifying same. The liquified gas41now moves on to a storage container90by way of a fluid passageway82which couples the storage container90, and the refrigeration assembly80, in fluid flowing relation one relative to the other.

In the method10as described above, the step of pressurizing the liquid32includes pressurizing the liquid to a pressure which causes the resulting high pressure gas41to have a pressure of at least about 150 pounds per square inch. Still further, the step of supplying the high pressure gas41to the expansion engine80comprises providing a gas output63having a reduced temperature of less than about 50 degrees C., and a pressure greater than about 1 ATM or ambient. In the embodiments as shown inFIGS. 1,2and3, and which are useful in practicing the method of the present invention, the expansion engine60may comprise a turbo-expander which is coupled in fluid receiving relation relative to the high pressure gas42. In this arrangement, the turbo-expander generates a power output which is transmitted by way of the transmission pathway or other force or work transmission means64and which provides a preponderance of the power or other work needed by the refrigeration assembly80to liquefy the gas41. The liquified gas is delivered to the storage container90and may be utilized for a number of different purposes including being utilized as a fuel. In the step of providing the expansion engine60, and coupling it in fluid flowing relation relative to the hydrogen dryer50, and the source of high pressure gas41which is generated by the container11, the expansion engine60is operable to reduce the temperature of the high pressure gas to at least about −200 degrees F., and further reduce the pressure of the gas to less than about 150 pounds per square inch.

Operation

The operation of the described embodiments of the present invention are believed to be readily apparent and are briefly summarized at this point.

A method of liquefying a gas10of the present invention includes the steps of providing a container11and supplying a liquid32to the container. Still further, the method comprises coupling a charging pump30in fluid flowing relation relative to the container11to increase the pressure of the liquid within the container. Still further, the method comprises providing a reactant compound40such as a metal or metal hydride and supplying the reactant compound40to the liquid30which is under pressure in the container. One example of an acceptable liquid is water, and an acceptable metal hydride is sodium borohydride or sodium hydride. The reactant compound40upon being received in the container11, chemically reacts with the liquid32to generate a high pressure gas41. If a chemical hydride such as sodium borohydride is supplied, the resulting high pressure gas41comprises hydrogen. An expansion engine60is provided and is coupled in fluid flowing relation relative to the container11by way of a conduit61and is operable to receive the high pressure gas41. The expansion engine60, upon receiving the high pressure gas, provides a resulting power or work output which is supplied to a refrigeration assembly80, and also produces a gas output63having a reduced temperature and pressure. As earlier disclosed, the expansion engine is coupled in fluid flowing relation relative to the refrigeration assembly80. The gas having reduced temperature and pressure provided by the expansion engine60, is supplied to the refrigeration assembly for further cooling. The power or work output provided by the expansion engine is supplied by the expansion engine to energize and/or actuate, at least in part, the refrigeration assembly. The refrigeration assembly80, when energized and/or actuated, liquifies the gas having reduced temperature and pressure and which is delivered from the expansion engine60. As earlier disclosed, the reactant compound40may comprise metals or metal hydrides and the gas which is liquified comprises liquid hydrogen which is held in the storage container90. The liquified hydrogen may be used as a fuel for various devices such as fuel cells and internal combustion engines.

Therefore, the present method of liquifying a gas provides a convenient means for both generating a high pressure gas such as hydrogen and then liquifying same. The present method also provides a convenient solution to the acknowledged problem of a hydrogen infrastructure which would permit hydrogen to be generated in an acceptable form at remote geographical locations and which would be suitable as a fuel.