Optimization of biodiesel production from clary sage oil: A Taguchi approach

The transition to renewable alternatives is imperative to address the global fuel crisis, environmental degradation, and the depletion of fossil fuel reserves. This study investigates the production of biodiesel from Clary sage seed oil, with process optimization conducted using the L₉ Taguchi orthogonal array. Due to a high free fatty acid content of 5.07 %, a two-step transesterification process was employed, involving sulfuric acid-catalyzed esterification followed by sodium hydroxide-catalyzed transesterification. Optimal conditions were identified as 0.5 wt% catalyst loading, a reaction time of 60 min, a temperature of 70 °C, and a methanol-to-oil molar ratio of 6:1. The contributions of these parameters to biodiesel yield were 86.72 %, 10.58 %, 1.57 %, and 1.13 %, respectively. Under these conditions, a theoretical biodiesel yield of 95.12 % was predicted, closely matching the experimental yield of 94.86 %, with only a 0.26 % deviation. Gas chromatography analysis confirmed the presence of fatty acid methyl esters, with linolenic acid (46.96 %) as the predominant component, followed by linoleic (19.44 %) and oleic acids (15.34 %). The physicochemical properties of the resulting biodiesel were found to be in close agreement with EN 14214 standards, confirming its suitability as a sustainable fuel alternative.