Laboratory Evaluation of Additives for Flame Luminosity Improvement in Neat Methanol Fuel

Neat methanol fuel (M100) has many advantages for achieving low emission levels as an automotive fuel, but there are several items that require attention before this fuel can replace conventional fuels. One item involves the low flame luminosity of methanol. An extensive literature search and laboratory evaluation were conducted to identify potential additive candidates to improve the luminosity of a methanol flame. Potential compounds were screened based on their concentration, luminosity improvement, and duration of luminosity improvement during the burn. Three compounds were found to increase the flame luminosity for segments of the burn at relatively low concentrations: toluene, cyclopentene, and indan. In combination, these three compounds markedly improved the luminosity of methanol throughout the majority of the burn. The two combinations were 1) 4 percent toluene plus 2 percent indan and 2) 5 percent cyclopentene plus 5 percent indan in methanol. Outdoor burns performed in bright sunlight were then performed on neat methanol, ethanol, M85, the two additive blends in methanol, and gasoline on five different surfaces: concrete, asphalt, sheet metal, grass, and soil to determine the flame luminosity under real world conditions. Test results indicated that the flames from methanol containing the luminosity additives were considered similar to flames produced by M85 and ethanol.