Improving Combustion Characteristics of Fatty Acid Esters Derived From Coconut Oil for Aviation Biofuel Applications

In response to the growing demand for sustainable aviation fuels (SAFs) with reduced life-cycle CO2 emissions and lower production energy requirements, this study investigated the feasibility of producing aviation biofuels using a co-solvent method originally developed for biodiesel production. The proposed method enables transesterification reactions at ambient temperature and pressure, significantly lowering the energy consumption compared to conventional hydroprocessing-based aviation biofuel production techniques. Coconut oil was selected as the feedstock because of its favorable carbon number distribution, particularly its high lauric acid (C12) content. Ethyl laurate was synthesized as the main fuel component and several blended fuels were prepared by adding various bio-derived esters. Physicochemical properties, including the flash point, lower heating value (LHV), and freezing point, were evaluated. Combustion tests were conducted using a micro-jet engine to assess engine performance (combustion efficiency, thermal efficiency, and specific fuel consumption) and emissions (CO, CO2, HC, and NO). The results indicated that certain blends, particularly those containing 80–90% ethyl laurate and 10–20% pentyl acetate or ethyl butyrate—exhibited thermal and combustion efficiencies comparable to or exceeding those of Jet A-1, although their LHVs remained lower. A comparative evaluation using a usefulness index (Ui) demonstrated that ethyl laurate-based blends offer promising potential as SAFs, especially when optimized for the flash point and energy density. This study highlights the viability of low-energy, co-solvent-based production methods for SAFs and provides a foundation for further research on performance optimization and large-scale applications.