Application of deep eutectic solvent in biodiesel reaction: RSM optimization, CI engine test, cost analysis and research dynamics

[Display omitted] •Application of DES as a partial substitute to methanol in transesterification reaction.•Processed crude glycerol was used first time in DES preparations.•At optimum conditions, biodiesel yield of 95% was obtained.•Biodiesel produced using this method showed lower emission. In this study, biodiesel was produced from waste cooking oil (WCO) in one step process with crude glycerol-ChCl based deep eutectic solvent (DES) and NaOH catalyst. Response surface methodology (RSM) technique was employed in predicting the optimal operating conditions and to study the relationship between reaction parameters and the yield of fatty acid methyl ester (FAME). The RSM coefficient of determination (R2) was observed to be 0.9965. The highest yield of biodiesel was 95% at the optimum reaction temperature of 65 °C with a reaction time of 90 min. The FAME produced was in compliance with the American standard for testing materials (ASTM) D6751-07 (2007) standards. CI engine test of B100 biodiesel fuel emitted lesser CO (2.01 g/kWh), HC (0.02 g/kWh) for engine load of 100% with little increase in CO2 when compared to petroleum-based diesel (PBD). Lower calorific value of biodiesel resulted in higher brake specific fuel consumption (BSFC) compared to the PBD. Computed biodiesel production cost was approximately 833.35 USD/ton. This investigation opens new pathway for utilizing crude glycerol-ChCl based DES as co-solvent for transesterification and other chemical reactions.