Method and apparatus for fueling vehicles with liquefied natural gas

Claim 3

A method according to claim 1 in which: natural gas vapor accumulates in the primary insulated storage tank; and natural gas vapor is withdrawn from the primary insulated storage tank and is combined with the liquefied natural gas withdrawn from the primary insulated storage tank, after the pressure on the withdrawn liquefied natural gas has been increased, to form a combined stream which is fed through the heat exchanger.

Claim 4

A method according to claim 1 in which: some of the liquid natural gas withdrawn from the primary storage tank and then increased in pressure is mixed with the warmed and pressurized liquefied natural gas exiting the heat exchanger and the resulting mixture is fed to the vehicle tank.

Claim 5

A method according to claim 1 in which the liquefied natural gas in the primary insulated storage tank is at about 15 psia to 45 psia and a temperature of about -258° F. to -230° F.

Claim 6

A method according to claim 1 in which: the heat exchanger is a direct contact heat exchanger and the pressurized liquefied natural gas is warmed therein by direct contact with vapor withdrawn from the primary insulated storage tank.

Claim 9

A method according to claim 6 in which: the liquefied natural gas is delivered to the vehicle tank without a substantial change in temperature and pressure from that at which it is stored in the dispensing tank.

Claim 10

A method according to claim 6 in which: natural gas vapor accumulates in the primary insulated storage tank; and natural gas vapor is withdrawn from the primary insulated storage tank and is combined with the liquefied natural gas withdrawn from the primary insulated storage tank, after the pressure on the withdrawn liquefied natural gas has been increased, to form a combined stream which is fed through the heat exchanger.

Claim 11

A method according to claim 6 in which: vapor forms in the dispensing tank and the vapor is returned to the primary insulated storage tank.

Claim 12

A method according to claim 6 in which: some of the liquefied natural gas withdrawn from the primary storage tank and then increased in pressure is fed into admixture with liquefied natural gas withdrawn from the dispensing tank to form a blended mixture having a controlled temperature and pressure which is fed to the vehicle tank.

Claim 13

Amethod according to claim 6 in which: some of the liquefied natural gas withdrawn from the primary storage tank and then increased in pressure is fed into admixture with the warmed and pressurized liquefied natural gas from the heat exchanger, and then the resulting blended admixture is fed to the dispensing tank.

Claim 14

Apparatus comprising: a primary insulated storage tank containing liquefied natural gas at a pressure close to atmospheric pressure and at a temperature close to its boiling point; a heat exchanger; a first conduit communicating with the liquefied natural gas in the primary tank and with the heat exchanger, said conduit including a pump, for withdrawing liquefied natural gas from the primary tank, increasing the pressure of the withdrawn liquefied natural gas and feeding it to the heat exchanger wherein the pressurized liquefied natural gas is warmed to a temperature no more than about -220° F. to -126° F. when at a pressure of about 50 psig to 550 psig; a vehicle using liquefied natural gas as its fuel and having an insulated fuel tank on board for receiving liquefied natural gas; and a second conduit communicating with the heat exchanger and the vehicle fuel tank for receiving the warmed and pressurized liquefied natural gas from the heat exchanger and feeding it to the vehicle fuel tank for storage as a liquid therein at a temperature of about -220° F. to -126° F. and a pressure of about 50 psig to 550 psig and at an approximate saturated condition.

Claim 15

Apparatus comprising: a primary insulated storage tank containing liquefied natural gas at a pressure close to atmospheric pressure and at a temperature close to its boiling point; a heat exchanger; a first conduit communicating with the liquefied natural gas in the primary tank and with the heat exchanger, said conduit including a pump, for withdrawing liquefied natural gas from the primary tank, increasing the pressure of the withdrawn liquefied natural gas and feeding it to the heat exchanger wherein the pressurized liquefied natural gas is warmed to a temperature no more than about -220° F. to -126° F. when at a pressure of about 50 psig to 550 psig; a vehicle using liquefied natural gas as its fuel and having an insulated fuel tank on board for receiving liquefied natural gas; and a second conduit communicating with the heat exchanger and the vehicle fuel tank for receiving the warmed and pressurized liquefied natural gas from the heat exchanger and feeding it to the vehicle fuel tank for storage as a liquid therein at a temperature of about -220° F. to -126° F. and a pressure of about 50 psig to 550 psig and at an approximate saturated condition.

Claim 16

Apparatus according to claim 12 in which: the primary storage tank has a natural gas vapor space; and a natural gas vapor withdrawal conduit communicates with the primary tank vapor space and with the conduit communicating with the primary tank and with the heat exchanger.

Claim 17

Apparatus according to claim 12 comprising: a third conduit communicating with the first conduit and the second conduit for admixing streams of liquefied gas to be fed through the first and second conduits to the third conduit to form an admixed stream and for delivering the admixed stream to the vehicle fuel tank.

Claim 18

Apparatus according to claim 12 in which: the heat exchanger is a direct contact heat exchanger and the pressurized liquefied natural gas is warmed therein by direct contact with vapor withdrawn from the primary insulated storage tank.

Claim 19

Apparatus comprising: a primary insulated storage tank containing liquefied natural gas at a pressure close to atmospheric pressure and at a temperature close to its boiling point; a heat exchanger; a first conduit communicating with the liquefied natural gas in the primary tank and with the heat exchanger, said conduit including a pump, for withdrawing liquefied natural gas from the primary tank, increasing the pressure of the withdrawn liquefied natural gas and feeding it to the heat exchanger wherein the pressurized liquefied natural gas is warmed to a temperature of about -220° F. to -126° F. when at a pressure of about 50 psig to 550 psig and so that the liquefied natural gas is at an approximate saturated condition; a stationary insulated natural gas dispensing tank located at a vehicle liquefied natural gas refueling facility; a second conduit for feeding the warmed and pressurized liquefied natural gas from the heat exchanger to the stationary insulated natural gas dispensing tank for storage in the said dispensing tank at an approximate saturated condition and at a temperature of about -220° F. to -126° F. and a pressure of about 50 psig to 550 psig; a vehicle using liquefied natural gas as its fuel and having an insulated fuel tank on board for receiving liquefied natural gas; and a third conduit communicating with the dispensing tank and the vehicle fuel tank for receiving warmed and pressurized liquefied natural gas from the dispensing tank and feeding it to the vehicle fuel tank for storage therein at a temperature of about -220° F. to -126° F. and a pressure of about 50 psig to 550 psig and at an approximate saturated condition.

Claim 20

Apparatus comprising: a primary insulated storage tank containing liquefied natural gas at a pressure close to atmospheric pressure and at a temperature close to its boiling point; a heat exchanger; a first conduit communicating with the liquefied natural gas in the primary tank and with the heat exchanger, said conduit including a pump, for withdrawing liquefied natural gas from the primary tank, increasing the pressure of the withdrawn liquefied natural gas and feeding it to the heat exchanger wherein the pressurized liquefied natural gas is warmed to a temperature of about -220° F. to -126° F. when at a pressure of about 50 psig to 550 psig and so that the liquefied natural gas is at an approximate saturated condition; a stationary insulated natural gas dispensing tank located at a vehicle liquefied natural gas refueling facility; a second conduit for feeding the warmed and pressurized liquefied natural gas from the heat exchanger to the stationary insulated natural gas dispensing tank for storage in the said dispensing tank at an approximate saturated condition and at a temperature of about -220° F. to -126° F. and a pressure of about 50 psig to 550 psig; a vehicle using liquefied natural gas as its fuel and having an insulated fuel tank on board for receiving liquefied natural gas; and a third conduit communicating with the dispensing tank and the vehicle fuel tank for receiving warmed and pressurized liquefied natural gas from the dispensing tank and feeding it to the vehicle fuel tank for storage therein at a temperature of about -220° F. to -126° F. and a pressure of about 50 psig to 550 psig and at an approximate saturated condition.

Claim 21

Apparatus according to claim 16 in which: the primary storage tank has a natural gas vapor space; and a natural gas vapor withdrawal conduit communicates with the primary tank vapor space and with the conduit communicating with the liquefied natural gas in the primary tank and with the heat exchanger for combining the vapor with the liquefied natural gas.

Claim 22

Apparatus according to claim 16 including: a fourth conduit communicating with the first conduit and the third conduit for feeding pressurized liquefied natural gas into admixture with warm liquefied natural gas withdrawn from the dispensing tank to thereby form a blended stream of liquefied natural gas to feed to the vehicle tank.

Claim 23

Apparatus according to claim 16 including: conduit means for withdrawing natural gas vapor from the dispensing tank and returning it to the primary storage tank.

Claim 24

Apparatus according to claim 16 comprising: a fourth conduit communicating with the first conduit and with the second conduit for feeding pressurized liquefied natural gas into admixture with warm liquefied natural gas withdrawn from the heat exchanger to thereby form a blended stream of liquefied natural gas to feed to the dispensing tank.