Viscosity and Density of Narrow Distillation Cuts from Refined Petroleum- and Synthetic-Derived Distillates in the −60 to +60 °C Range

Abstract

Aviation turbine fuel (jet fuel) must remain fluid enough for use at low temperatures typically experienced during high-altitude flights. The viscosity–temperature relationship of petroleum-derived jet fuel is described by the MacCoull correlation in ASTM D341. The maximum kinematic viscosity of jet fuel at −20 °C is regulated by specification, but for long-distance flights, viscosity of <12 mm2 s–1 at −40 °C is important. For synthesized paraffinic kerosene (SPK) to be approved as a synthetic jet fuel, compliance with these viscosity limits is imperative. A petroleum-based kerosene and SPK from wax hydrocracking were distilled into narrow cut (5 °C range) fractions, and for each narrow cut, density, viscosity, and refractive index values were measured over the temperature range from +60 to −60 °C. The viscosity–temperature dependences of the petroleum-derived and synthetic narrow cuts were described with comparable accuracy (relative deviation <5%) by the MacCoull correlation. Calculation of kinematic viscosity at −40 °C by extrapolating data measured at ≥−20 °C underpredicted viscosity for >200 °C boiling kerosene cuts, with a maximum relative deviation of 6.6%. The freezing point is another jet fuel property that is regulated by specification. Good agreement (±1.3 °C) was found between the end of the melting endotherm obtained by differential scanning calorimetry (DSC) and the freezing point determined according to ASTM D2386. Local maxima/minima in the freezing point of distillation cuts with increasing boiling point were observed and could be related to the freezing point characteristics of the n-alkanes.

Sustainable aviation fuel: Pathways to fully formulated synthetic jet fuel via Fischer–Tropsch synthesis

“…The low temperature flow properties of FT SPK obtained from wax hydrocracking was investigated and compared to petroleum derived kerosene 40 . For the materials used in this case study, it was found that the low temperature viscosity of the FT SPK was lower than that of the petroleum derived kerosene.…”

Error quantification of the Arrhenius blending rule for viscosity of hydrocarbon mixtures

“…It is worth noting however that the temperature dependence implied by Eq. 3 is significantly simpler than a variety of empirically derived relationships (Sloane and Winning, 1931;Link and de Klerk, 2022) that are more accurate over a limited temperature range, which implies that ΔE is also temperature dependent.…”