LNG Fueling Facilities

The CFI fueling strategy is a “closed loop” design based on a patented two-line vent-fill fuel transfer procedure that eliminates temperature stratification at the gas/liquid interface inside the vehicle fuel tank. Using this procedure, the vapor that is vented from the tank during the fueling process is recovered to the bulk storage tank. With both lines connected the vent gas exiting from the ullage space at the top of the vehicle fuel tank is maintained at the same design temperature, -240° F, as the temperature of the LNG being transferred into the tank.

The operating pressure that is required in the vehicle fuel tank can then be maintained, totally independent of the LNG's saturation pressure, thus eliminating any need to heat or precondition the LNG to increase its saturation pressure. The result is a much lower cost, more reliable fueling facility and fueling operation.

LNG Enthalpy vs Temperature vs Density vs. Pressure
LNG PROPERTIES CRYOGENIC FUELS INC
TWO LINE FILL
CONVENTIONAL INDUSTRIAL GAS
SINGLE LINE FILL
Temperature: -260°F -240°F -220°F -200°F
Saturation Pressure: 0 psig 18 psig 50 psig 100 psig
Density: 26.5 lbs/ft3 25.5 lbs/ft3 24.3 lbs/ft3 21.6 lbs/ft3
Enthalpy: 122 btu/lb 138 btu/lb 157 btu/lb 174 btu/lb

The above data are from the “Pressure Enthalpy Chart for Methane”, published by the National Institute of Standards and Technology (NIST). This data is provided, as reference for users in understanding the phase change relationships that occur in LNG with respect to enthalpy, temperature, density, and pressure.

As the data clearly shows, the maximum fuel density/energy storage is at -240° F, or colder. Therefore, an LNG vehicular fuel tank and fueling facility capable of operating at these temperature and pressure conditions will benefit the fleet user with increased vehicle range, improved reliability in fueling and a substantial reduction in fueling facility capital and operating costs.

Technology Comparison

LNG PROPERTIES CRYOGENIC FUELS INC
TWO LINE VENT FILL
CONVENTIONAL INDUSTRIAL GAS
SINGLE LINE NO VENT FILL
Fill Pressure: 60 - 120 PSI 120 - 200 PSI
LNG Temperature: -240°F -200°F
LNG Density: 3.45 lbs/Gallon 3.0 lbs/Gallon
LNG Methane Content: Standard 95% Refined 99%
Energy Content: 1047 btu/SCF 900 btu/SCF