Optimization of quicklime-catalyzed biodiesel production from hemp (Cannabis sativa L.) seed oil

This study focuses on the development of a sustainable biodiesel production process using non-edible hemp seed oil (HSO) and an environmentally friendly, lowcost quicklime catalyst. HSO was recovered via cold-pressing, with major fatty acids identified as linoleic acid (55.70%), linolenic acid (15.59%) and oleic acid (13.72%). Due to the slightly elevated free fatty acids (FFAs) content in HSO, a two-stage process was employed: esterification of FFAs in HSO catalyzed by sulfuric acid, followed by methanolysis of the esterified HSO using quicklime as a catalyst. The methanolysis reaction was optimized using a 33 factorial design with three central points, combined with response surface methodology (RSM). The optimal reaction conditions for achieving maximum fatty acid methyl esters (FAME) content were determined to be: methanol-to-HSO molar ratio of 6:1, catalyst concentration of 6.8%, and reaction time of 45 min. Additionally, the produced biodiesel meets the EN 14214 biodiesel quality standard specifications, with the exception of the iodine value. Overall, the methanolysis of non-edible HSO using low-cost quicklime presents a promising, sustainable approach for biodiesel production.