Flammability properties of hydrocarbon solutions in air

Abstract

Work on the interrelations of the flammability properties of n-olkanes in air has been extended to both vapor and liquid fuel mixtures. By 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 properties which were studied include: lower and upper flammability limits, heat of combustion, stoichiometric concentration, flash point, and flammability index ("explosiveness"). Experimentally determined flash points of multicomponent solutions were in good agreement with the calculated values, confirming the point that hydrocarbon solutions follow the above laws, and also confirming the concept of flash point as that temperature at which the vapor concentration above a liquid is equal to that at its lower flammability limit. The derived equations demonstrate why vapor pressure of individual constituents plays a more important role than concentration on the overall flammability properties of liquid solutions, and that a very small amount of a highly volatile contaminant in a relatively nonflammable fuel may make it flammable.

Flash-point prediction for binary partially miscible mixtures of flammable solvents

“…However, it deviated significantly from the experimental measurements for multiple organic-water solutions [16]. Overall, application of the former models [3,10,11,15] is limited to solutions that can be assumed as ideal within the composition range considered. The new models taking into account non-ideality of the solution through liquid phase activity coefficients have to be used to predict efficiently the flash point of these miscible mixtures [4,5,9,12,16].…”

“…Introducing activity coefficient models to model the non-ideal behavior of liquids, various models have been proposed recently for predicting the flash point of binary aqueous-organic and solvent/salt systems [5,9], with successful verification based on comparison with the experimental data. Previously, Affens and McLaren [10] (1972) have developed a predictive model to determine the flash points of binary hydrocarbon mixtures based on Raoult's law. White et al, [11] (1997) have reduced this model to a simpler equation by ignoring any dependence of the lower flammable limit on temperature.…”

Parameter's Estimate in Wilson Equation

“…Several prediction models are presented in the literature for the prediction of mixture flash point have reported a series of models, which could be used for predicting the flash points for ideal and non ideal solutions (see e.g., [1], [3], [5]- [9], [10], [12], [13]). The imperfectness of the liquid phase is accounted by liquid-phase activity coefficients by means of thermodynamic models.…”

The Measurement of Flash Point of Water-Methanol and Water-Ethanol Systems Using Seta Flash Closed Cup Tester

“…Affens and McLaren (6) (9) predicted the flash point of the binary flammable mixtures using the optimizing methods based on the van Laar and NRTL equations. Methanol is mixed with water and injected into high performance diesel and gasoline engines for an increase of power and a decrease in intake air temperature in a process known as water-methanol injection.…”