Homogeneous-Base Catalysed in Situ Transesterification of Desert Date Kernels: Biodiesel Yield and Methanol Recovery Maximization

Depletion of petroleum reserves and environmental-related problems such as climate change have triggered research towards sustainable and green substitutes for petroleum-based products. Biodiesel has been identified as a good replacement for conventional diesel. The traditional two-step biodiesel production approach can increase the capital and operating costs due to the requirement of two different units for extraction and the reaction. To overcome the problem, this research was carried out to produce biodiesel from desert date seeds through in situ potassium-hydroxide-catalysed methanolysis. Experimental investigations were conducted under different operating conditions, including temperature, time, and catalyst dosage. The optimal yield of 98.1% was achieved in 120 minutes at 50 °C using 3 g of catalyst. The one-factor at-time designed experimental data were analysed using Design Expert 13. Catalyst dosage was a significant model term, while time and temperature were not statistically significant, corroborating the experimental observation. The optimisation results predicted an optimal biodiesel yield of 86.9% at a reaction temperature of 50 °C, a reaction time of 160 minutes, and a 3 g catalyst dosage, which is close to the result obtained from the experimental investigation. The results from the characterisation showed that the product has the properties of biodiesel, and the cake can be useful for pyrolytic production of bio-oil and biochar since the cake had fat and carbohydrate contents of 38.432 and 43.911%, respectively.