Dairy waste scum as a potential feedstock for bio-diesel production: optimisation, quality and reliability studies

ABSTRACT Dairy waste scum obtained from the downstream milk production process is a potential source to produce biodiesel. It’s a less dense floating solid mass that primarily consists of triglycerides and fatty acids, which are important constituents for fuel. The present study aims to produce biodiesel using dairy waste scum by a transesterification process using NaOH/KOH catalysts. The present work identifies the better catalyst between two alkaline catalysts NaOH and KOH, using low-cost methodologies. The preliminary confirmation characteristics, such as density, calorific value, Kinematic Viscosity, Specific Gravity, Flash Point, and Fire Point will support the formation of synthesised biodiesel via the proposed methodology. The experimental results lead to a yield of 89.02% of biodiesel using NaOH catalyst with optimised process parameters of the temperature of 55°C, the reaction time of 120 min, and catalyst loading of 1 wt./wt.%. Finally, biodiesel was tested for emission and combustion characteristics in a CI engine. To optimise the process parameters, the response surface methodology (RSM) along with Bootstrap estimation has been performed using MINITAB19. Furthermore, the experimental and predicted yields obtained from ANOVA were reported.