Hybrid entropy-VIKOR optimization of Jatropha curcas biodiesel synthesis with advanced transesterification reaction input parametric analysis for yield, viscosity, and density

Abstract

Biodiesel, derived from triglyceride conversion, presents itself as a sustainable and environmentally friendly alternative to fossil diesel fuel to meet the increasing global energy demand. Lipid-rich, non-edible Jatropha curcas oil presents itself as a prime feedstock for biodiesel synthesis. A batch transesterification reactor was used in this research to experimentally facilitate the conversion of Jatropha curcas oil into biodiesel with homogenous KOH as a catalyst. The present study investigates a combined approach using a fractional factorial design for screening, followed by a novel hybrid Entropy-VIKOR approach for ranking experimental alternatives to achieve maximum yield and minimum viscosity of produced biodiesel. A separate statistical approach is also employed to analyze the combined effects of transesterification reaction input parameters (catalyst loading and reaction temperature; chemical interaction time, and methanol-to-lipid molar ratio) on the resulting yield, viscosity, and density, using 3D surface plots and empirical relations. The combined experimental and numerical based investigation indicated that the optimum biodiesel produced from Jatropha curcas oil with yield: 93.16 %, viscosity: 4.0 cSt, and density: 871–881 kg/m³ and these results are obtained under the following conditions: Homogenous base catalyst loading of 1.5 % (w/w), reaction temperature of 65 °C, chemical interaction time of 120 min, and a methanol-to-lipid molar ratio of 6:1. The resulting composition of Jatropha curcas oil-based biodiesel have physicochemical characteristics within specified limits as per international EN 14214 standards.