The primary fuel used within the general aviation industry is a petroleum based gasoline blended with small amounts of tetraethyl lead (a lead-based additive used to increase the octane number of gasoline without affecting its performance) called 100 LL aviation gasoline. Lately, concern has mounted regarding the health effects of leaded aviation gasoline. This, in addition to the increasing price of 100 LL, has led to research involved with developing an unleaded avgas with the ability to meet performance regulations and safely operate the entire general aviation fleet without engine modifications. In this paper, we assess the vapor liquid equilibrium of two newly developed unleaded avgas fluids. For complex fluids such as gasoline, the distillation curve provides the most practical approximation of this property. The distillation curves of these two fluids were measured using the advanced distillation curve method. The advanced distillation curve method uses temperature, volume, and pressure measurements of low uncertainty, providing true thermodynamic state points that can be modeled with an equation of state, greatly aiding in the design of new fuels. In addition, the advanced distillation curve method incorporates a composition explicit data channel allowing precise qualitative identification as well as quantitative analyses of each distillate fraction. In this paper we present the distillation curves and track the composite enthalpy of combustion of the two unleaded aviation gasolines throughout their distillation. The results from this study are compared to previous vapor liquid equilibrium and composite enthalpy of combustion measurements done on 100 LL aviation gasoline.
Citation: Energy and Fuels
Pub Type: Journals
aviation gasoline, chemical analysis, distillation curve, enthalpy of combustion