Methane Propane LNG Gasoline Diesel Hydrogen Methanol Ethanol
Formula CH4 C3H8 CH4 C8 H18 C12H26 H2 CH3OH C2H5OH
Research Octane Number 130 112 130 91-98 N.A 130+ 107 108
Motor Octane Number 130 97 130 83-90 N.A N.A 91 92
Cetane Number -10 5-10 -10 8-14 40-65 N.A 3 8
Density of Liquid Fuel(kg/lt) N.A 0.509 0.421 0.746 0.808 0.0708 0.79 0.783
Density of Gas (kg/m3) 0.6512 0.508 N.A 4.4 0.0838
Boiling Point (C) -162 -42 -162 27-240 -252.7
Lower Heating Value (kj/kg) 49,913 46,238 49,913 42,661 43,419 119,444 19,859 26,855
Energy Content (Volume) (BTU/gallon) 121,459 84,448 28,287 114,194 125,881 N/A N/A 57,449
Energy Compared to Gasoline 65% 72% 66% 100% 113% 26% 47% 66%
Energy Compared to Diesel 57% 64% 60% 88% 100% 23% 41% 58%
Stoichometric A/F Ratio (mass) 17.3 15.7 17.3 14.7 15 34.3 6.5 9
Heat of Vaporization (kj/kg) 507 423 507 355 286 N.A 1186 842
Energy of Stoich. Mixture (Vapor) 3.58 3.79 3.58 3.55 3.61 3.58 3.45 3.46
Wobbe Number (Mj/m3) 50.66 74.7 50.66 N.A N.A
Autoignition Temperature (C) 540 482 450 257 316 574 464 423
Peak Flame Temperature (C) 1790 1990 1790 1977 2054 2045
Spark Ignition Energy (mj) 0.29 0.305 0.29 0.24 0.24 0.02
Flammability Limits (vol %) 5.3-15 2.1- 10.4 1.4- 7.6 0.6- 5.5 4-75
Max. Burning Velocity in NTP air (cm/s) 37-45 43-52 37-45 37-43
Specific Gravity at NTP (60 deg F) 0.55 1.52 0.55 2-4 4-6
Reid Vapor Pressure (psi) 2400 208 8-15 0.2 4.6 2.3
Flame Visibility, relative 0.6 0.6 0.6 1 1
Flash Point (F) -300 -100 to -150 -306 -45 165 52 55

* @ 3500 psi