Process and apparatus for conditioning cryogenic fuel to establish a selected equilibrium pressure

A method of conditioning cryogenic fuel comprising the steps of:

• (a) withdrawing liquefied cryogenic fuel from a primary storage tank at a low pressure and at a temperature close to the boiling point of the liquefied cryogenic fuel;
• (b) feeding the liquefied cryogenic fuel through an indirect heat exchanger;
• (c) feeding the liquefied cryogenic fuel to a sparger or mixer chamber;
• (d) withdrawing vapor from a vapor space in the primary storage tank and compressing the vapor;
• (e) feeding the compressed vapor to a vapor storage tank and storing the vapor therein at a selected pressure;
• (f) feeding the vapor from the vapor storage tank through the indirect heat exchanger wherein the vapor is cooled to near a saturation temperature thereof, and alternatively at least partially condensed, the heat from the cooling and condensing of the vapor warming the liquefied cryogenic fuel being fed through the heat exchanger;
• (g) sparging the vapor and any condensate exiting the heat exchanger into the liquefied cryogenic fuel in the sparger or mixer chamber, said sparging step condensing the remaining vapor from the heat exchanger;
• (h) feeding the warmed liquefied cryogenic fuel from the sparger or mixer chamber into a vehicle fuel tank;
• (i) measuring the temperature of the liquefied cryogenic fuel exiting the sparger or mixer chamber;
• and
• (j) providing liquefied cryogenic fuel at a selected equilibrium pressure to the vehicle fuel tank by varying a flow rate of the vapor exiting the vapor storage tank in response to the temperature of the liquefied cryogenic fuel exiting the sparger chamber.

A fuel delivery apparatus comprising:

• (a) a primary storage tank for storing liquefied cryogenic fuel, said tank having a vapor space;
• (b) a vapor storage tank in communication with the vapor space of the primary storage tank, said vapor storage tank for storing vapor from the primary storage tank at a selected pressure greater than a pressure in the primary storage tank;
• (c) means for warming liquefied cryogenic fuel from the primary storage tank by indirect transfer of heat from vapor from the vapor storage tank to the liquefied cryogenic fuel and subsequent transfer of heat of condensation of the vapor to the liquefied cryogenic fuel, said cryogenic fuel warming means in communication with both the primary storage tank and the vapor storage tank;
• (d) means for dispensing warmed liquefied cryogenic fuel from the cryogenic fuel warming means, said dispensing means in communication with said warming means and connectable to a vehicle fuel tank;
• (e) a temperature sensor disposed in the dispensing means;
• and
• (f) means for controlling a flow rate of vapor from the vapor storage tank to the cryogenic fuel warming means in response to a signal from the temperature sensor, said control means in communication with the vapor storage tank.

A fuel delivery apparatus comprising:

• (a) a primary storage tank for storing liquefied cryogenic fuel, said tank having a vapor space;
• (b) a first conduit having a compressor disposed therein and communicating with the vapor space of the primary storage tank;
• (c) a vapor storage tank communicating with the first conduit, said vapor storage tank for storing vapor from the primary storage tank at a selected pressure greater than a pressure in the primary storage tank;
• (d) a second conduit in communication with the vapor storage tank having a valve disposed therein;
• (e) a third conduit in communication with liquefied cryogenic fuel disposed in the primary storage tank;
• (f) a heat exchanger for transferring heat from vapor fed through said second conduit to liquefied cryogenic fuel being fed through said third conduit;
• (g) a sparger or mixer chamber in communication with both said second conduit arid said third conduit;
• (h) a fourth conduit communicating with a downstream portion of the sparger or mixer chamber with respect to a direction of flow of fluid through the sparger or mixer chamber;
• (i) a temperature sensor disposed in the fourth conduit;
• and
• (j) means for controlling a flow rate of vapor through the second conduit in response to a signal from the temperature sensor, said control means in communication with the valve in the second conduit.