Claims
- 1. Apparatus for delivering, on a demand basis, high pressure compressed natural gas comprising a relatively large storage tank for containing a quantity of LNG at a relatively low pressure, a plurality of separate pressurizing and heating vessels, means for selectively delivering LNG to individual ones of the vessels at a relatively low pressure, means for selectively supplying heat to individual ones of the vessels, each of said vessels being arranged so that heat from said heat supplying means is absorbed by LNG contained therein in a manner wherein the LNG in the vessel is elevated to a relatively high delivery pressure of several thousand psi and heated by energy received primarily in the form of heat from said heat supplying means, means for conveying natural gas pressurized to a high level in a vessel to a delivery point, a compressor having an inlet and an outlet and being capable of raising the pressure of natural gas from a pressure level at least as low as that at which LNG is delivered to the vessel by the delivery means, to a substantially higher pressure at its outlet, and means for selectively coupling the compressor inlet to any of said vessels, in a manner free of fluid communication with the tank, in which a charge of LNG has been substantially completely pressurized.
- 2. Apparatus for delivering, on a demand basis, high pressure compressed natural gas comprising a relatively large storage tank for containing a quantity of LNG at a relatively low pressure, a plurality of separate pressurizing and heating vessels, means for selectively delivering LNG to individual ones of the vessels at a relatively low pressure, means for selectively supplying heat to individual ones of the vessels, each of said vessels being arranged so that heat from said heat supplying means is absorbed by LNG contained therein in a manner wherein the LNG in the vessel is elevated to a relatively high delivery pressure of several thousand psi greater than the pressure existing in the storage tank and heated by energy received primarily in the form of heat from said heat supplying means, means for conveying natural gas pressurized to a high level in a vessel to a delivery point, a compressor having an inlet and an outlet and being capable of raising the pressure of natural gas from a pressure level at least as low as that at which LNG is delivered to the vessel by the delivery means, to a substantially higher pressure at its outlet, means for selectively coupling the compressor inlet to any of said vessels in a manner free of fluid communication with the tank in which a charge of LNG has been substantially completely pressurized and a cascade subsystem in which compressed natural gas converted from LNG in said vessels is stored in a series of gas storage tanks having a preselected range of differential pressures.
- 3. Apparatus as set forth in claim 2, including a means for directing natural gas from the outlet of the compressor to a gas storage tank having the highest operating pressure below that of the compressor outlet.
- 4. Apparatus as set forth in claim 3, including valving means for selectively connecting the outlet of the vessels to a gas storage tank having the highest operating pressure below that of the connected vessel.
- 5. Apparatus as set forth in claim 4, including valving means to direct gas to a low pressure service line when said gas storage tanks are filled to capacity.
- 6. A method of supplying high pressure compressed natural gas from a storage tank of LNG maintained at relatively low pressure to satisfy an intermittent demand substantially continuously through the period of the demand comprising the steps of providing a plurality of vessels, charging one of said vessels with a volume of LNG at a pressure not substantially greater than that existing in the storage tank, while the one vessel is being charged with LNG transferring heat to a charge of LNG previously introduced into another of said vessels to cause the LNG to be pressurized and heated to a gas at a relatively high pressure, substantially higher than the pressure in the storage tank, allowing high pressure gas to express itself from a vessel other than said one vessel in which such gas has been formed from a low pressure charge of LNG introduced therein in a manner substantially the same as that used to charge said one vessel and thereafter having been subjected to heating to convert it to a high pressure gas, and purging a vessel other than said one vessel from which a charge of LNG has been converted to and expressed as a high pressure gas by coupling the inlet of a gas compressor to the vessel being purged whereby such vessel is made ready to receive a new charge of LNG from the storage tank at a pressure not substantially greater than that existing in the storage tank, the charging, pressurizing and heating and purging operations in each vessel being performed successively and cyclically.
- 7. A method of refueling a road transportation vehicle comprising receiving and storing liquid natural gas in a relatively large supply tank capable of holding several thousand gallons at relatively low cryogenic temperature and moderate pressure of about 30 to 100 psi, dispensing the liquid natural gas from the supply tank generally exclusively on demand when a vehicle is present for refueling, converting the dispensed gas to compressed natural gas at relatively high pressure of several thousand psi and moderate near ambient temperature through the addition of energy to the gas primarily in thermal form while simultaneously delivering the gas to a high-pressure fuel tank on the vehicle, the liquid natural gas being dispensed from the storage tank into a closed vessel and being thereafter converted to high-pressure, moderate temperature gas by the addition of heat while in or in free communication with the closed vessel and being thereafter dispensed into a fuel tank on a vehicle.
- 8. A method of refueling a road transportation vehicle comprising receiving and storing liquid natural gas in a relatively large supply tank capable of holding several thousand gallons at relatively low cryogenic temperature and moderate pressure of about 30 to 100 psi, dispensing the liquid natural gas from the supply tank generally exclusively on demand when a vehicle is present for refueling, converting the dispensed gas to compressed natural gas at relatively high pressure of several thousand psi and moderate near ambient temperature through the addition of energy to the gas primarily in thermal form while simultaneously delivering the gas to a high-pressure fuel tank on the vehicle, liquid natural gas being dispensed from the storage tank at relatively low pressure and temperature into alternate units of a plurality of conversion vessels, the liquid natural gas dispensed in one of said conversion vessels being heated to convert it to a high-pressure, moderate temperature gas while another of said conversion tanks is being filled with liquid natural gas from the storage tank at relatively low temperature and pressure for subsequent pressurization and heating, relatively high-pressure, moderate temperature gas being dispensed from successive ones of the conversion vessels into a vehicle fuel tank.
- 9. Apparatus for delivering, on a demand basis, high pressure compressed natural gas comprising a relatively large storage tank for containing a quantity of LNG at a relatively low pressure, a plurality of separate pressurizing and heating vessels, means for selectively delivering LNG to individual ones of the vessels at a relatively low pressure, means for selectively supplying heat to individual ones of the vessels, each of said vessels being arranged so that heat from said heat supplying means is absorbed by LNG contained therein in a manner wherein the LNG in the vessel is elevated to a relatively high delivery pressure of several thousand psi and heated by energy received primarily in the form of heat from said heat supplying means, means for conveying natural gas converted to a supercritical state and pressurized to a high level in a vessel to a delivery point, a compressor having an inlet and an outlet and being capable of raising the pressure of natural gas from a pressure level at least as low as that at which LNG is delivered to the vessel by the delivery means, to a substantially higher pressure at its outlet, and means for selectively coupling the compressor inlet to any of said vessels in a manner free of fluid communication with said tank in which a charge of LNG has been substantially completely pressurized.
BACKGROUND OF THE INVENTION
This application is a continuation-in-part of application Ser. No. 649,238, filed Jan. 29, 1991, now U.S. Pat. No. 5,107,906, which application is a continuation of application Ser. U.S. Pat. No. 416,145, now abandoned filed Oct. 2, 1989.
US Referenced Citations (22)
Foreign Referenced Citations (2)
Number |
Date |
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5142198 |
Nov 1980 |
JPX |
1095012 |
May 1984 |
SUX |
Continuations (1)
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Number |
Date |
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Parent |
416145 |
Oct 1989 |
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Continuation in Parts (1)
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Number |
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649238 |
Jan 1991 |
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