Review of Biofuel from Waste Cooking Oil for Compression Ignition Engines

Biodiesel derived from waste cooking oil (WCO) appears to be a promising renewable fuel for compression ignition (CI) engines, potentially reducing environmental impact while utilizing waste resources.This review synthesizes current research on WCO biodiesel, focusing on production methods, properties, engine performance, emissions, and comparisons with other biodiesels like soybean and rapeseed.Transesterification, often requiring pre-treatment for high free fatty acid (FFA) content, is the primary production method.WCO biodiesel exhibits higher viscosity and density but comparable cetane numbers to diesel.Engine performance studies suggest slightly lower brake thermal efficiency (BTE) and higher specific fuel consumption (SFC), while emissions data indicate reductions in carbon monoxide (CO), hydrocarbons (HC), and particulate matter (PM), though nitrogen oxides (NOx) may increase.Compared to other biodiesels, WCO biodiesel offers sustainability advantages but faces challenges like feedstock variability and production costs.This paper highlights WCO biodiesel's potential and identifies future research directions to optimize its use in CI engines.