Enhanced biodiesel synthesis from palm fatty acid distillate and modified sulfonated glucose catalyst via an oscillation flow reactor system

Abstract

Due to potential depletion and environmental issues caused by fossil fuel usage, the search for alternative source became necessary. Biodiesel synthesis in recent times has received research attention as an energy source that is renewable and sustainable. In this study, glucose acid catalyst was synthesized via modified sulfonation approach and was successfully utilized in a continuous oscillatory flow reactor to produce an environmentally friendly biodiesel under atmospheric conditions. Palm fatty acid distillate (PFAD) feedstock consisting of >90% free fatty acid was employed in a single step esterification reaction. The prepared modified sulfonated glucose catalyst was characterized utilizing FTIR, XRD, TPD-NH3, FESEM, EDX and BET. The optimization of the process parameters conducted in the oscillation flow reactor (OFR) achieved >97% conversion of the PFAD to biodiesel with 94.21% FAME yield. The optimum process parameters for optimum conversion by the synthesized catalyst were 2.5 wt.% catalyst loading, 6 Hz oscillation frequency, 9:1 molar ratio, 60 °C temperature of reaction and 50 min residence time. The OFR consisting of tubes with orifice plate baffles spaced equally has indicated to be an efficient technology for biodiesel synthesis utilizing the heterogeneous acid catalyst. The efficient catalyst was reusable for up to four cycles with minimal loss in activity achieving about 80% conversion at the fourth cycle.