Valorization of waste cooking oil based biodiesel for biolubricant production in a vertical pulsed column: Energy efficient process approach

Highlights: • Response surface methodology was applied for multi-objective optimization. • An optimal yield of 83.3% and power consumption of 1006 kW/m³ were obtained. • The interaction of molar ratio and catalyst load has greatest effects on yield. • Baffle spacing does not affect yield and power consumption considerably. • Waste cooking oil based biolubricant met the requirements of ISO-VG10 standard. -- Abstract: Development of bio-based lubricants have received growing interest as sustainable substitutes to petroleum-based lubricants due to their renewability, biodegradability and superior physicochemical properties. Biolubricant production from waste cooking oil in an intensified reactor, which is designed with the aim of scaling-up for industrial purposes, can effectively decrease the cost of finished product. In this study, a vertical pulsed column with tri-orifice baffles was applied to produce trimethylolpropane fatty acid triester (biolubricant) from waste cooking oil, which is a cost and environmentally effective feedstock. This type of reactor enables high interfacial areas between immiscible reactants, leading to improved reaction performance. In addition, response surface methodology was used to optimize the levels of different operating parameters to obtain the highest reaction yield and the lowest power consumption. An optimal reaction yield of 83.3% and power consumption of 1006 kW/m³ were obtained with an oscillation frequency of 3.6 Hz, a baffle spacing of 1.45d_e, a molar ratio of 4:1 and a potassium carbonate catalyst loading of 1%.