Biodiesels from non-catalytic transesterification of plant oils and their performances as aviation fuels

Abstract

In accordance with the rapid growth of aviation industry, consumption of aviation fuel played a critical role as one of the major contributors of anthropogenic CO2 emission. As such, the use of aviation fuels derived from the renewable resources have gained considerable attention. To this end, this study theoretically examined the performance of aviation fuels derived from lipids in six plant oils (olive, coconut, soybean, canola, avocado, and sesame). Prior to the thermodynamic calculations, biodiesels were produced by thermally induced non-catalytic transesterification of lipids. A non-catalytic conversion platform led to conversion of plant oils into biodiesels with higher than 90% yield at 380 degrees C in 1 min, while the base-catalyzed reaction with KOH showed same yields after 8 h of reaction at 60 degrees C. An ideal gas turbine cycle of an aircraft turbojet engine was adopted to calculate the jet fuel performances of biodiesels from non-catalytic transesterification of six plant oils. As references, performances of conventional jet fuels (Jet A and JP-4) through the turbojet engine were estimated with a constant air supply. For complete combustion of fuels, biodiesels required 14 - 18% more fuel consumption rate than conventional jet fuels. The more fuel consumption rate for combustion of biodiesel led to higher engine and specific thrusts of turbojet engine, comparing to conventional jet fuels. As the result, propulsion and thermal efficiencies of biodiesels were similar with those of conventional jet fuels. Given that biodiesel is considered as a carbon neutral fuel, it was offered that jet fuels blended with biodiesel can contribute to the mitigation of CO2 emissions with no fuel performance change.