Nickel Nanoparticle-Directed Flow Synthesis of Biodiesel from Waste Cooking Oil

Geopolitical turmoil and energy security drive the global demand of renewable fuel for affordable transportation purpose. Developing countries are divesting conventional agrarian products and simultaneously investing on biodiesel research to capture a significant renewable market share. The most promising features of biodiesel that are nothing, but methyl/ethyl esters of fatty acids are considered as clean fuel due to reduced CO 2 emission, less toxic, and biodegradable as well. Earlier the synthesis of biodiesel from fatty acids are performed by energy-intensive batch processes. In this work, we have designed a helical-straight-helical (HSH) glass reactor of one meter length with 5 mm internal diameter for flow synthesis of biodiesel. Transesterification reaction has been performed carried in a HSH flow reactor for conversion of waste cooking oil and crude palm oil to biodiesel. Magnetic Nickel nanoparticle has been utilized in presence alkali KOH as well for catalytic conversion of fatty acids. Progress of reaction has been visualized by capturing images at different zones of reactor. Biodiesel production has been optimized by varying the flow-rate and molar ratio between methanol and oil. In continuous synthesis at an oil flow rate of 350 µL/min, 12:1 molar ratio and 70 °C temperature we have achieved 82% conversion for waste cooking oil and 92% for crude palm oil to biodiesel. Biodiesel obtained has also been characterized from its properties like density, kinematic viscosity, calorific value, and acid value from both the feedstock and was found in the range of ASTM standards. Graphical Abstract