LNG COCKTAILS AS ALTERNATIVE TRANSPORTATION FUELS
Liquid hydrocarbon fuels may be extended by liquefying natural gas under pressure at ambient temperature as a mixture with LPG (liquefied petroleum gas), gasoline, diesel or other appropriate hydrocarbon fuel. Such mixtures may be described as LNG (liquefied natural gas) cocktail fuels and would be marketed as a bottled gas-type fuel. The liquefaction pressures required are quite high particularly for the heavier fuels such as gas diesel oil. The minimum liquefaction pressures at 38-40 °C for 30% W/W liquefaction of methane in propane, n-butane, n-octane and cetane are approximately 90 (9.0), 120 (12), 260 (26) and 540 (54) bar (MPa) respectively (1 bar = 0.1 MegaPascal). Experimental conversion kits for LNG cocktail fuels need to be developed and tested for spark-ignition (SI) and compression-ignition (CI) engines. The conversion kit for SI engines could be based on commercially available LPG kits while that for CI engines would require a more detailed investigation.