Sulfated Fly‐Ash Catalyzed Biodiesel Production from Maize Acid Oil Feedstock: A Comparative Study of Taguchi and Box‐Behnken Design

Abstract

AbstractIn the present investigation, the waste utilization approach has been followed for the bioenergy production. The focus is on the fly ash utilization for the development of heterogeneous catalyst synthesis under solvent‐free conditions. The fly ash is one of the environmental pollutant and unwanted material in thermal power plants. The sulfated fly ash (SFA) catalyst is synthesized by the sulfonation of waste fly ash. This catalyst has been characterized by various analysis such as elemental, thermal, spectral, surface area, acidity and basicity etc. The catalyst has been found to exhibit various phases such as Quartz, Mullite, Hematite, Lime etc. and thermally stable upto 550 °C. The results obtained from NH3‐TPD and CO2‐TPD analysis, confirms the presence of acid (0.401 mmol / g) and basic (0.197 mmol / g) sites in the SFA catalyst. Further, the utility of SFA catalyst has been demonstrated in the biodiesel production via esterification reaction from maize acid oil (MAO) feedstock containing high free fatty acid (FFA) (127.21 mg KOH / g). The maize acid oil is one of the biowaste feedstock, mainly a by‐product obtained from the refining of crude maize oil. Taguchi method and Box‐Behnken Design (BBD) have been applied to investigate the effect of different reaction parameters on the biodiesel production. The use of SFA catalyst has been found to be advantageous especially, in the biodiesel production from feedstock with high FFA content.