Comparative Evaluation of Biodiesel Yield, Fuel Properties and Oxidative Stability of Waste Cooking Oil and Selected Niger Delta Plant Oils

Abstract

Background: Biodiesel production from waste and locally available plant oils may support renewable fuel development while valorising lipid resources. Aim: This study comparatively evaluated biodiesel yield, fuel properties and oxidative stability of biodiesel produced from waste cooking oil, coconut oil, palm kernel oil and African oil bean seed oil. Materials and Methods: Biodiesel was produced by alkaline-catalysed transesterification. Yield, density, kinematic viscosity, acid value, flash point, cetane number, moisture content, calorific value, cold flow properties, oxidative stability and storage stability were evaluated using the stated ASTM, EN, AOAC and AOCS procedures. Data were analysed by one-way ANOVA at p < 0.05. Results: Biodiesel yield ranged from 88.7 ± 1.7% for African oil bean seed oil to 95.8 ± 1.1% for palm kernel oil. Density ranged from 0.869 ± 0.003 to 0.887 ± 0.004 g/cm³, while kinematic viscosity ranged from 4.06 ± 0.08 to 4.82 ± 0.12 mm²/s. Palm kernel oil biodiesel recorded the highest cetane number (62.8 ± 1.2), calorific value (41.3 ± 0.5 MJ/kg) and induction period (10.54 ± 0.24 h). Waste cooking oil biodiesel had the lowest induction period (6.94 ± 0.20 h) but retained acceptable measured fuel properties. Palm kernel and coconut oil biodiesel met the stated EN 14214 oxidative-stability threshold. Conclusion: The evaluated feedstocks produced biodiesel with distinct yield, fuel-quality and stability profiles, with palm kernel oil showing the strongest overall performance and waste cooking oil remaining a viable waste-derived feedstock.