Process optimization and catalyst poisoning study of biodiesel production from kusum oil using potassium aluminum oxide as efficient and reusable heterogeneous catalyst

Abstract

In present study, low cost single phase potassium aluminum oxide (K2Al2O4) was synthesized by solid state route and used as catalyst for production of biodiesel from a rural feedstock kusum oil via methyl transesterification reaction. The prepared catalyst was characterized by various techniques. Feedstock comprises high fatty acid content 20.19 mg of KOH/g. Conversion of biodiesel was performed by esterification, a pretreatment step followed by transesterification and best experimental conditions for esterification to lower FFA from 20.19 to 0.67 mg of KOH/g were molar ratio of 1:10 (oil: methanol), 1.5% v/v H2SO4 and 60 min of reaction time at 65 ± 0.5 °C temperature whereas for transesterification to obtain methyl esters were 1:15 M ratio of oil: methanol, 1.0 wt. % catalyst (K2Al2O4), at 65 ± 0.5 °C temperature, reaction time of 90 min and 650 rpm agitation speed resulted into 97.08% conversion. The catalyst showed five cycle reusability without significant erosion of the conversion after high temperature regeneration. In addition, the tolerance of prepared catalyst against water, FFA and phospholipids were also investigated. Kinetic and green chemistry metrics (E-Factor) formulation were also studied. The fatty acid composition of synthesized methyl ester was ascertained by GCMS. Moreover, the physicochemical properties of synthesized methyl ester fuel were appraised according to the ASTM standard and were found to be within the ASTM D 6751 specifications. © 2018 Elsevier Ltd