Improving cold flow and stability of leftover cooking oil based biodiesel through blending with kerosene and diesel

Abstract This study investigates the technical feasibility of producing biodiesel from leftover cooking oil, a non-edible feedstock that avoids competition with food supply and reduces the cost associated with biodiesel production. The leftover cooking oil, sourced from the one of UEM restaurant, initially had a high FFA content of 1.623%, necessitating a two-step transesterification process. The first step effectively reduced the FFA to 0.724%, making it suitable for further conversion. Key reaction parameters were optimized, concluding an oil-to-methanol ratio of 1:6, a reaction temperature of 60 °C under atmospheric pressure, and continuous mixing at 600 revolutions per second for one hour. Blending petroleum diesel and kerosene with the produced biodiesel was further explored, with blends prepared in 5% increments up to 50% by volume. Both diesel and kerosene demonstrated good miscibility with the biodiesel, and the resulting blends, along with the pure biodiesel, maintained physical and chemical properties within standard limits. The cetane number equation, which was originally developed for biodiesel based on saponification and iodine values, was fitted to accurately assess the cetane number of the biodiesel blends. Cold flow properties were evaluated in a designed and controlled environment maintained between −17.8 °C and −13 °C using ice and acetone. Both diesel and kerosene blends showed improvements in subpar properties of B100, with kerosene blends, particularly at 50% (K50), exhibiting slightly better enhancement than diesel blends. This research highlights the potential of utilizing LCO for biodiesel production and its subsequent enhancement through blending, contributing to the development of sustainable alternative fuels.