FLAMMABILITY PROPERTIES OF HYDROCARBON FUELS. PART 3. FLAMMABILITY PROPERTIES OF HYDROCARBON SOLUTIONS IN AIR

Abstract : Previous work on the interrelations of the flammability properties of n-alkanes in air have been extended to both vapor and liquid fuel mixtures. Based on the application of Raoult's and Dalton's laws governing vapor pressure and composition above a solution of two or more liquid hydrocarbons to Le Chatelier's rule governing the flammability limits of vapor mixtures, equations have been derived which make it possible to predict overall flammability properties of mixtures from the properties and proportions of the individual components. The flammability properties which were studied include: lower and upper flammability limits, heat of combustion, stoichiometric concentration, flash point, and flammability index ('explosiveness'). The derived equations demonstrate, quantitatively, why vapor pressure of individual constituents plays a more important role than concentration on the overall flammability properties of liquid hydrocarbon solutions, and that a very small amount of a highly volatile contaminant in a relatively nonflammable fuel may make it flammable.