Modeling the Crystallization of Aviation Fuels Containing Different Amounts of Aromatic Hydrocarbons

Thermodynamic modeling is used to study the effect additives of a number of organic substances have on the temperatures of incipient crystallization of kerosene fractions (KFes) derived from crude oil (straight-run KFes (SRKFs)) and produced in the catalytic hydrocracking of heavy oil residues (HCKFs). Normal paraffins \({{{\text{C}}}_{n}}{{{\text{H}}}_{{2n + 2}}}\) (n = 9, 11, 16) are used as additives to KFes, and m-ethylbutylbenzene is employed as an aromatic hydrocarbon. It is shown the UNIFAC and UNIQUAC models allow the reproduction of published experimental data showing that adding normal paraffins to HCKFs greatly raises the freezing point when n ≥ 11. For SRKFs, this rise starts at n = 16. Calculations show that m-ethylbutylbenzene additives have hardly any effect on the temperature of incipient crystallization.