LIGHTER THAN AIR TRANSPORTATION SYSTEM USING CRYOGENIC ENERGY STORAGE

Abstract

A method for generating liquefied gas is provided. The method includes receiving air, refining the air to create refined air, performing liquefaction on refined air to form liquefied gas, and transferring at least one constituent liquefied gas of the liquefied gas to a storage tank in a lighter than air aircraft. The constituent liquefied gas(es) is configured to serve as an energy source for the lighter than air aircraft. The method may include distilling the liquefied gas to obtain liquid nitrogen and one or more other constituent gases. The liquid nitrogen may be configured to store at least 250 kilojoule per liter of energy. Additionally, the air may be refined to create refined air by compressing the air, separating water from the air, scrubbing carbon dioxide from the air, and/or filtering dust from the air. The method may be carbon-neutral or carbon-negative.

Claims

1. A method for generation of liquefied gas comprising: receiving air; refining the air to create refined air; performing liquefaction on the refined air to form liquefied gas; transferring at least one constituent liquefied gas of the liquefied gas to a storage tank in a lighter than air aircraft, wherein the at least one constituent liquefied gas of the liquefied gas is configured to serve as an energy source for the lighter than air aircraft.

2. The method of claim 1, further comprising: distilling the liquefied gas to obtain liquid nitrogen and one or more other constituent gases, wherein the at least one constituent liquefied gas of the liquefied gas includes the liquid nitrogen.

3. The method of claim 2, wherein the liquid nitrogen is configured to store at least 250 kilojoule per liter of energy.

4. The method of claim 2, wherein the liquid nitrogen possesses a storage temperature of greater than approximately −200 degrees Celsius.

5. The method of claim 2, wherein distilling the liquefied gas generates oxygen and argon.

6. The method of claim 1, wherein refining the air to create refined air includes at least one of: compressing the air; separating water from the air; scrubbing carbon dioxide from the air; or filtering dust from the air.

7. The method of claim 6, wherein refining the air to create refined air includes scrubbing carbon dioxide from the air, wherein the method further comprises: performing molten carbonate electrolysis to separate carbon from oxygen.

8. The method of claim 7, further comprising: manufacturing components of another lighter than air aircraft utilizing separated carbon.

9. The method of claim 1, wherein the method is carbon-neutral or carbon-negative.

10. A lighter than air aircraft comprising: an air inlet that is configured to receive air; one or more refinement equipment that is configured to refine the air to generate refined air; liquefaction equipment that is configured to perform liquefaction on the refined air to form liquefied gas; a storage tank that is configured to store at least one constituent liquefied gas of the liquefied gas; and a heat exchanger, wherein the heat exchanger is configured to induce a phase change in the at least one constituent liquefied gas from liquid to gas, wherein the phase change generates energy, and wherein the lighter than air aircraft is configured to use the energy to power one or more components or systems of the lighter than air aircraft.

11. The lighter than air aircraft of claim 10, wherein the one or more refinement equipment includes at least one of: an air compressor for compressing the air; a water filter for separating water from the air; a carbon dioxide scrubber configured to scrub carbon dioxide from the air; or a dust filter for filtering dust from the air.

12. The lighter than air aircraft of claim 11, wherein the one or more refinement equipment includes an air compressor for compressing the air, wherein the air compressor is a three-stage compressor.

13. The lighter than air aircraft of claim 10, wherein the liquefied gas is configured to store at least 250 kilojoule per liter of energy.

14. The lighter than air aircraft of claim 10, wherein the lighter than air aircraft is carbon-neutral or carbon-negative.

15. The lighter than air aircraft of claim 10, wherein the liquefaction equipment is configured to perform liquefaction using at least one of a Hampson-Linde cycle, a Siemens cycle, or a Claude cycle.

16. A lighter than air aircraft comprising: a storage tank that is configured to store a liquefied gas; a heat exchanger, wherein the lighter than air aircraft is configured to receive the liquefied gas for the storage tank from a liquefied gas production and storage facility or a second lighter than air aircraft, wherein the heat exchanger is configured to induce a phase change in the liquefied gas from liquid to gas, wherein the phase change generates energy, and wherein the lighter than air aircraft is configured to use the energy to power one or more components or systems of the lighter than air aircraft.

17. The lighter than air aircraft of claim 16, wherein the liquefied gas is nitrogen.

18. The lighter than air aircraft of claim 16, wherein the heat exchanger utilizes at least one of heat from ambient air or solar energy.

19. The lighter than air aircraft of claim 16, further comprising: a turboexpander; and a generator, wherein the liquefied gas is expanded through the turboexpander to convert the energy to rotational motion, and wherein the generator is configured to convert rotational motion into electrical energy.

20. The lighter than air aircraft of claim 16, further comprising: a deployable boom, wherein the lighter than air aircraft is configured to receive the liquefied gas from the second lighter than air aircraft using the deployable boom or to transfer the liquefied gas to the second lighter than air aircraft using the deployable boom.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

[0023] FIG. 1 is a schematic view illustrating an example LTA aircraft flying in for a direct fill of liquefied gas, in accordance with some embodiments discussed herein;

[0024] FIG. 2 is a schematic view illustrating an example LTA tanker obtaining liquefied gas and then transferring the liquefied gas to another LTA aircraft by aerial transfer, in accordance with some embodiments discussed herein;

[0025] FIG. 3 is a schematic diagram of an example system for production of liquefied gas that may be used on land, at sea, or onboard an LTA aircraft, in accordance with some embodiments discussed herein;

[0026] FIG. 4 is a schematic view illustrating an example hybrid liquefied gas-electric power generation and propulsion system for an LTA aircraft, in accordance with some embodiments discussed herein; and

[0027] FIGS. 5A and 5B are block diagrams illustrating an example non-pollutant cargo transportation system with built-in carbon capture and sequestration, in accordance with some embodiments discussed herein.

DETAILED DESCRIPTION

[0028] Example embodiments of the present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the example embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. It should be understood that the drawings and detailed descriptions here are not intended to limit implementations to the particular form disclosed but that the intention is to cover all modifications, equivalents and alternatives falling within the scope and spirit of the description herein.

[0029] In some embodiments, liquefied gas production may be performed at a liquefied gas production and storage facility remote from an LTA aircraft, and an LTA aircraft may fly in for direct fill of liquefied gas. FIG. 1 is a schematic view illustrating an example LTA aircraft 140 flying in for a direct fill of liquefied gas. Electrical energy may be generated through one or more renewable sources 100. Renewable sources 100 may be solar photovoltaics in some embodiments, but renewable sources 100 may take other forms. The renewable source(s) 100 may be used to run a motor 110, and the motor 110 may be an electric motor. The motor 110 may power air liquefaction equipment 120. Once powered, the air liquefaction equipment 120 may produce liquefied gases, and these liquefied gases are pumped into and stored in one or more storage tanks 130. In some embodiments, the liquefied gases may undergo distillation to separate various atmospheric constituents within the liquefied gases (e.g. nitrogen, oxygen, argon, etc.), and each of these atmospheric constituents may be stored in separate storage tank(s) 130. Storage tank(s) 130 may be insulated and/or unpressurized storage tanks 130. Additionally, when stored within the storage tanks 130, the liquefied gases may be kept below their boiling points to limit boil-off losses.

[0030] As illustrated in FIG. 1, an LTA aircraft 140 may fly to a location proximate to the storage tank(s) 130. In the illustrated embodiment of FIG. 1, the LTA aircraft 140 follows the path 150 downwardly towards the liquefied gas production and storage facility 105 where its onboard liquefied gas storage tank is filled. Once filling is complete, the LTA aircraft 140 takes off along path 160 and resumes its course to its destination. These liquefied gas production and storage facilities 105 may be placed at the beginning, end, or at any point along a route.

[0031] Liquefied gas that has been transferred to an LTA aircraft may be stored in one or more storage tanks onboard the LTA aircraft. Liquefied gas may be pumped from the storage tank of the liquefied gas production and storage facility 105, and the liquefied gas may be pumped onboard the LTA aircraft 140. Liquefied gas may be transferred to the one or more storage tanks within the LTA aircraft 140 in some embodiments.

[0032] Once in the LTA aircraft 140, the liquefied gas may be pumped using heat exchangers using heat from ambient air or solar thermal energy. This heat may induce a phase change from liquid to gas and may expand the gas, such as through a turboexpander, converting the stored kinetic energy to rotational motion. This rotational motion may be converted into electrical energy with an electrical generator. Electrical energy that is produced may be used for various purposes on the LTA aircraft 140. For example, the electrical energy may be utilized to power electric motors for propulsion, electrical servomechanisms for attitude controls, avionics, navigation, radio equipment, and/or other applications aboard the LTA aircraft. However, other uses for the electrical energy can also be made.

[0033] In some embodiments, an LTA tanker may fly into a liquefied gas production and storage facility so that a storage tank of the LTA tanker may be filled with liquefied gas, and the LTA tanker may then fly to rendezvous points along predetermined transport routes where other LTA aircraft may rendezvous with the LTA tanker so that the LTA aircraft may refill liquefied gas by aerial transfer. FIG. 2 is a schematic view illustrating an example LTA tanker obtaining liquefied gas and then transferring the liquefied gas to another LTA aircraft by aerial transfer.

[0034] As illustrated in FIG. 2, electrical energy generated through renewable sources 200, such as solar photovoltaics, is used to run an electrical motor 210, powering air liquefaction equipment 220 to produce liquefied gases, which are pumped into and stored in insulated, unpressurized storage tanks 230. An LTA tanker 240 is provided as one type of LTA aircraft. The LTA tanker 240 may land at the liquefied gas production and storage facility 205 so that its one or more liquefied gas storage tanks may be filled with liquefied gas. This liquefied gas may be cryogenic, liquefied gas. The LTA tanker 240 then takes off and navigates to a predetermined position along a designated transport route 250. Additionally, another LTA aircraft 260 may travel along path 280 to a location proximate to the stationed LTA tanker 245. When an LTA aircraft 260 arrives and needs its liquefied gas storage tanks refilled, the stationed LTA tanker 245 may deploy, for example, its liquefied gas transfer boom 270. The boom 270 may be a retractable, gimballed boom in some embodiments. The LTA aircraft 260 flies in formation with the stationed LTA tanker 245 while the boom is attached to the intake port of the LTA aircraft 260. The liquefied gas storage tanks of the LTA aircraft 260 are filled from the stationed LTA tanker 245 via the boom 270. When filling is complete, the LTA aircraft 260 disengages from the boom 270 and continues its journey along the transport route 280. The stationed LTA tanker 245 may or may not refill more than one LTA aircraft 260, or the same LTA aircraft 260 multiple times. When the stationed LTA tanker 245 is empty, it returns along path 290 to the liquefied gas production and storage facility 205 to refill its liquefied gas storage tanks. This cycle continuously repeats as necessary.

[0035] FIG. 3 is a schematic diagram of an example system for production of liquefied gas that may be used on land, at sea, and/or onboard an LTA aircraft. In FIG. 3, a Claude cycle is used to produce liquefied gas. However, Hampson-Linde and Siemens cycles may also be used for liquefied gas production, but are not shown. Electrical energy generated through renewable resources 300 is conducted to an electrical motor 303. The electric motor shaft turns a three-stage compressor including a first stage compressor 306, a second stage compressor 309, and a third stage compressor 312. As the 3-stage compressor turns, air is drawn into the first stage compressor 306, where the air is compressed and exits the first stage compressor 306 and is run through an intercooler 318 where heat generated through the compression process is rejected. This pressurized and cooled air is then drawn into the second stage compressor 309 where the air is further compressed and is then run through a second intercooler 321 where heat generated through the compression process is rejected. This pressurized and cooled air is then drawn into the third stage compressor 312 where the air is further compressed and is then run through a third intercooler 324 where heat generated through the compression process is rejected.

[0036] After running through the three-stage compressor, air may be high-pressure air that has been cooled to a temperature near the ambient temperature. The air may then pass through a regenerator 327. The regenerator 327 may be a heat exchanger. Upon leaving the regenerator 327, the air flow is divided into two separate lines at junction 330. For example, fifteen percent of the air flow may pass through a first line 331 into an expander 333, but other amounts of air may flow through the first line 331 to the expander 333 in other embodiments.

[0037] The expander 333 may be a turboexpander in some embodiments, and the expander 333 may be configured to convert stored energy (which may be kinetic energy) to rotational motion. This rotational motion may be converted into electrical energy with an electrical generator. Electrical energy that is produced may be used for various purposes on the LTA aircraft 140 (see FIG. 1) or at a liquefied gas production and storage facility 105 (see FIG. 1). For example, the electrical energy may be utilized to power electric motors for propulsion, electrical servomechanisms for attitude controls, avionics, navigation, radio equipment, and/or other applications aboard the LTA aircraft. However, other uses for the electrical energy can also be made.

[0038] The remaining air may pass through a second line 354. The air passing through the expander 333 produces energy. In some embodiments, the expander 333 produces at least 250 kilojoules of energy for each liter of liquefied gas. In some embodiments, the expander 333 produces approximately 287 kilojoules of energy for each liter of liquefied gas. The air exiting the expander 333 is substantially cooled. This cooled air from the expander 333 is then combined at junction 339 with gas 345 from the liquid/gas separator 342 and put through a second regenerator 351, where it is used to chill the compressed air coming in the second line 354 from the junction 330. The second regenerator 351 may be a heat exchanger. The chilled, compressed air coming out of the second regenerator 351 passes into a valve 357 where it is further cooled, liquefying a portion of the air and passing into the liquid/gas separator 342. The valve 357 may be a well-insulated throttling valve in some embodiments, and the valve 357 may be a Joule-Thomson valve in some embodiments. Liquefied air 348 may then be pumped via a pump 360 to a distiller 362 for fractional distillation and/or to a storage tank 364 so that liquified air 348 may be stored for later distribution. The gas 345 from the liquid/gas separator 342 and the gas from the expander 333, which combine at junction 339 to pass through the second regenerator 351, then passes through the first regenerator 327 to pre-cool the gas passing through the other side of the first regenerator 327 before it is divided at junction 330. After pre-cooling the incoming gas in the first regenerator 327, this gas may be recycled back to the intake 363 and mixed into the incoming air.

[0039] FIG. 4 is a schematic view illustrating an example hybrid liquefied gas-electric power generation and propulsion system for an LTA aircraft. Liquefied gas 400 is stored in an insulated, low-pressure storage tank 403 aboard an LTA aircraft. To start the power generation system, the starter/generator 406 draws power from an onboard starter battery (not shown), which is connected to common shaft 415 by a reduction mechanism 407. The starter/generator 406 turns the gas compressor 409 and gas expander 412 which are both connected to the common shaft 415. The operator may open the control valve 424. The gas compressor 409 draws in ambient air through the air inlet 418. The gas compressor 409 compresses the air, heats the air, and pumps the air through flow splitter 422, with some of the hot air flowing to air ejector 421, which creates negative pressure that draws in liquefied gas 400 from the liquefied gas storage tank 403 through the liquefied gas intake 427 and the control valve 424. The liquefied gas 400 mixes with the hot air from the gas compressor 409 in the air ejector 421, where the mixed gases then pass into the cold-side heat exchanger 430 where the mixed gases are heated through indirect contact with ambient air or air heated with solar thermal energy. The air in the hot-side heat exchanger 431 may be mixed with the additional flow of air from gas compressor 409. The air in the hot-side heat exchanger 431 may pass through the air ejector 423, and this may create negative pressure that draws in ambient or solar heated air at inlet 425, mixing air entering at inlet 425 with hot air from the gas compressor 409. This mixed air may pass through hot-side heat exchanger 431. In some embodiments, the air exiting hot-side heat exchanger 431 may be recycled to the solar heater for reheating. In some embodiments, the air exiting the hot-side heat exchanger 431 may be vented to the atmosphere 432.

[0040] The now heated air flowing from the cold-side heat exchanger 430 now expands through the gas expander 412 generating power on the common shaft 415. The common shaft then turns the gas compressor 409 to sustain the system for as long as there is liquefied gas 400 to pull from the storage tank 403. The expanded gas is exhausted to the atmosphere through the gas outlet 433. The shaft 415 also turns the reduction mechanism 407 which in turn drives the starter/generator 406. This may induce the starter/generator 406 to generate electrical energy which is then distributed to one or more propulsion unit motors 436. The propulsion unit motors 436 in turn convert the electrical energy into rotational motion, transmitting that motion, for example, through a clutch and reduction gearbox 439 to an aircraft propeller 441, which provides propulsion for the LTA aircraft. Generated electrical energy may also be used for other purposes in the aircraft.

[0041] Methods are also contemplated for the generation of liquefied gases. FIG. 5A and 5B are block diagrams illustrating an example non-pollutant cargo transportation system with built-in carbon capture and sequestration. Starting with FIG. 5A, electricity generation 500 occurs using wind energy 501 and solar energy 503. Electricity generation 500 results in the generation of electricity 502, and this electricity 502 may be considered renewable electricity. As described further herein, the electricity 502 may be utilized to provide energy during various processes described in FIG. 5B.

[0042] Looking again at FIG. 5A, air 507 is introduced. The air 507 may be introduced from the atmosphere or from some other source. The air 507 may undergo dust filtration 506 using a dust filter in some embodiments. The filtered air may be compressed at operation 505, and electricity 502 generated during operation 500 may be utilized to compress the filtered air. The compressed air is run through water separation 510, and fresh water 511 may be generated as an output of water separation 510 alongside dewatered, compressed air. The dewatered, compressed air generated by water separation 510 is run through a carbon dioxide scrubber 515, which removes carbon dioxide (CO2) 516. In some embodiments, the carbon dioxide 516 may be stored at the carbon dioxide scrubber 515 and/or at a storage tank outside of the carbon dioxide scrubber 515.

[0043] Liquefaction 520 is then performed on the dewatered and scrubbed air. With liquefaction 520, dewatered and scrubbed air undergoes a phase change from gas to liquid. Oxygen (O.sub.2) 521 may be used in liquefaction 520. The liquid air formed by liquefaction 520 then passes to distillation 525. At distillation 525, the liquid air may be separated into liquid oxygen (O.sub.2) 526, liquid argon (Ar) 528, and liquid nitrogen (N.sub.2) 527. Each of these gases may be stored in storage tanks, and these storage tanks may be insulated, low-pressure storage tanks. Liquid oxygen 526 and liquid argon 528 may be used for commercial purposes.

[0044] Looking now at FIG. 5B, it can be seen that the liquid nitrogen 527 obtained through distillation 525 in FIG. 5A may be used for filling energy storage tanks of cargo airships 535. Liquid nitrogen 527 may be used for filling storage tanks on the ground using ground refill 530 in some embodiments. In some embodiments, liquid nitrogen 527 may be used for filling storage tanks in the air using aerial refill 531.

[0045] Cargo airships 535 may pick up cargo and use liquid nitrogen 527 as an energy source. The liquid nitrogen may be expanded to gas, resulting in the release of energy. This released energy may propel the cargo airship 535 so that transportation 540 may be completed. During transportation 540 with the cargo airship 535, the cargo may be transported to its destination. In some embodiments, the only output during transportation 540 of the cargo airship 535 is inert, gaseous nitrogen 541 into the atmosphere. Thus, an environmentally conscious design may be accomplished.

[0046] Additionally, scrubbed carbon dioxide 516 may be used for beneficial purposes as well. Molten carbonate electrolysis 545 may be performed to convert the scrubbed carbon dioxide 516 into carbon nanotubes 546. Another byproduct of molten carbonate electrolysis 545 is oxygen 521, which may be utilized in liquefaction 520 as illustrated in FIG. 5A. Molten carbonate electrolysis 545 may be powered by the electricity 502 generated through electricity generation 500, using wind energy 501, and/or using solar energy 503. However, molten carbonate electrolysis 545 may be powered by other energy sources such as thermal energy, electric energy from another source, solar energy from another source, etc.

[0047] Carbon nanotubes 546 may be used as a feedstock for component manufacturing 550. Component manufacturing 550 may produce carbon nanotube (CNT) reinforced epoxy resin and spun 551A and/or woven carbon nanotube yarns and fabrics 551B. Component manufacturing 550 may rely upon electricity 502 generated through electricity generation 500. The carbon nanotube reinforced epoxy resin and spun 551A and/or woven carbon nanotube yarns and fabrics 551B may be used in manufacturing 560 of airship components 561, and the manufacturing 560 may be a composite manufacturing process in some embodiments. Manufacturing 560 may be performed to generate airship components 561. However, in other embodiments, the carbon nanotubes 546, the carbon nanotube (CNT) reinforced epoxy resin and spun 551A, and/or the woven carbon nanotube yarns and fabrics 551B may be utilized to generate components for other systems. Manufacturing 560 may rely upon electricity 502 generated through electricity generation 500.

[0048] Once manufactured, assembly 570 may be performed so that airship components 561 are assembled into cargo airships 535. In this way, cargo may be transported without carbon dioxide or other greenhouse gas emissions, and with the added benefit of atmospheric carbon dioxide capture within the cargo transport system and carbon sequestration within the cargo airships themselves. Energy for assembly 570 may be provided by electricity 502 generated through electricity generation 500.

[0049] In FIGS. 3 and 4, various lines are shown. Additionally, in FIGS. 5A and 5B, various operations are described where substances are transferred from one location to another. In some embodiments, an operator may manually control the flow of liquefied gas and other substances through the system, and this may result in an adjustment of the amount of power generated by the system. The control of the flow of liquefied gas and other substances may be accomplished by an automated electronic digital controller in some embodiments.

[0050] In some embodiments, LTA aircraft may utilize energy through liquefied gas expansion alongside other energy sources. For example, the LTA aircraft may utilize energy generated from solar-photovoltaic power alongside energy generated through liquefied gas expansion. In some embodiments, solar-photovoltaic power may be utilized for daytime running, and liquefied gas expansion may be utilized for energy generation during nighttime or periods of low solar availability. In some embodiments, energy generated from solar-photovoltaic power may be stored for use during nighttime or periods of low solar availability, and liquefied gas expansion may be utilized alongside solar-photovoltaic power during the daytime in other embodiments.

CONCLUSION

[0051] Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the embodiments of the invention are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the invention. Moreover, although the foregoing descriptions and the associated drawings describe example embodiments in the context of certain example combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the invention. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated within the scope of the invention. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.