A Model-Based Assessment of the Added Values of Hydroprocessed Esters and Fatty Acids–Synthetic Paraffinic Kerosene Blends on Aircraft Performance, Emissions, and Safety

Abstract

The aviation industry tries to reduce its carbon footprint by shifting toward sustainable aviation fuel (SAF). With the increasing proportion of SAF in the fuel mix, careful consideration must be given to mitigating any safety risks while realizing its full benefits. In this context, this study presents a comprehensive framework for assessing safety aspects together with the added values of SAF on aircraft performance and emissions. The framework enables the prediction of various performance metrics using composition-based property models and empirical correlations. A key aspect of this research is the systematic propagation of uncertainties inherent in the property prediction models and correlations. To illustrate the framework’s capabilities, two fuels representing the spectrum of conventional jet fuels were blended with hydroprocessed esters and fatty acids–synthetic paraffinic kerosene (HEFA-SPK) synthetic blend component (SBC) at various ratios. These blends were compared to a reference fuel, and the range of conventional fuels documented in the Coordinating Research Council (CRC) world fuel survey. The results indicate that the selected SBC can improve aircraft performance through enhanced specific energy (energy per unit mass). Additionally, the study reveals that HEFA-SPK can substantially reduce emissions, particularly nvPM, and thereby mitigate contrail-induced radiative forcing. However, the study also points out that safety-related properties, such as density and aromatic content, constrain higher blending ratios. Additionally, the study evaluates different modeling approaches for predicting soot emissions and LBO, revealing potential limitations in the existing models. The findings underscore the importance of a multimetric approach for fuel assessment. This work aims to provide a foundation for informed decision making in the development and implementation of SAF, ultimately contributing to the industry’s sustainability goals.