Innovative Catalysts for Biodiesel Generation from Edible Oils: Paving the Way for Cleaner Automobiles

The study aims to produce biodiesel from waste cooking oil and compare the effects of two different catalysts (KOH and CaO) on the transesterification process. Homogeneous catalysts and heterogeneous catalysts are the two types of catalysts used in the transesterification process to produce biodiesel. In the present investigation, homogeneous catalysts KOH and heterogeneous catalyst CaO are used in the transesterification reaction. Catalysts are used to accelerate the reaction and increase reaction efficiency. The reaction temperature is set at 65°C. A methanol-to-waste cooking oil ratio of 6:1 is used for KOH and 8:1 for CaO. The catalyst amount is maintained at 2% of the weight of palmitic acid relative to the weight of waste cooking oil. The reaction time is 150 minutes for KOH and 240 minutes for CaO catalysts. The blends include B50C (50% biodiesel with CaO as catalyst and 50% conventional diesel fuel), B50K (50% biodiesel with KOH as catalyst and 50% conventional diesel fuel), B100C (100% biodiesel with CaO as catalyst), and B100K (100% biodiesel with KOH as catalyst). The characteristics of the blends are assessed through the measurement of properties like viscosity, density, cetane number, and flash point. Biodiesel produced with heterogeneous catalyst (CaO) has a higher flash point and increased viscosity. It may be related to a less heterogeneous catalyst remaining in biodiesel fuel. The experimental test results indicate that biodiesel produced with heterogeneous catalyst (CaO) showed more power than its counterpart. The GHG emission (CO₂) is slightly higher for B50C & B100C. In the case of NOx emissions, it is higher for blends and particularly for B50C & B100C as the flash point is higher leading to increased combustion temperature.