Micro-Emulsification Vs. Transesterification: An Investigation Of The Efficacy Of Methanol Use In Improving Vegetable Oil Engine Performance

Biofuels have gained increasing prominence in recent times. Vegetable oils such as jatropha, koranja, and coconut oil have been investigated as alternatives to diesel in reciprocating engines. However, their use faces some challenges, prompting research into various methods for improving their performance. Among these, transesterification and micro-emulsification with methanol have emerged as key approaches. However, both require the use of additional materials and energy investments, which increases cost and reduces suitability. Despite this, the question of the comparative benefits of these approaches has not been thoroughly addressed. This work investigates the use of transesterification and micro-emulsification in improving coconut oil performance in a compression-ignition engine. Five fuels were tested, including diesel, biodiesel, and three methanol emulsions. Engine performance and emissions were assessed for each fuel at various engine load conditions. The additional energy requirement for both approaches was also considered. Both methods resulted in an improvement in combustion efficiency as compared to petro-diesel, but the additional energy requirement for biodiesel was higher. Micro-emulsification proved to be more energy efficient and yielded better emissions. The use of methanol in micro-emulsifications therefore has a clear advantage over its use in transesterification, for improving the performance of engines running on vegetable oils.