Cottonseed Oil Biodiesel: Production, Properties, Engine Performance, Emissions, Tribological, and Life Cycle Assessment

Abstract

The growing depletion of fossil fuel reserves and the environmental impacts of their use in internal combustion engines have accelerated the search for cleaner, renewable alternatives. Biodiesel has emerged as a promising candidate; however, many feedstocks still face challenges related to production methods, engine performance, emissions, and tribological compatibility. Cottonseed oil has attracted increasing attention as a sustainable and efficient biodiesel feedstock. This review highlights the major production techniques applicable to cottonseed oil biodiesel and evaluates its physicochemical properties, which conform to international American Society for Testing and Materials (ASTM) and European Norms (EN) standards. Studies have shown that cottonseed oil biodiesel blends offer improved environmental performance, with reduced emissions of Carbon monoxide (CO), Hydrocarbons (HC), and smoke opacity, although slightly elevated Nitrogen Oxide (NOx) emissions are observed. Engine performance metrics such as Brake-Specific Fuel Consumption (BSFC) and Brake Thermal Efficiency (BTE) are analyzed and compared with those of petroleum diesel, revealing the potential for optimization. Moreover, the high content of unsaturated fatty acids in cottonseed oil contributes to enhanced tribological properties, which may extend the engine component life. In addition, studies indicate that Life Cycle Assessment (LCA) is a key tool for analyzing cottonseed biodiesel as a renewable energy source. Overall, cottonseed oil biodiesel has strong potential as a renewable, low-emission fuel with improved lubrication characteristics, making it a viable alternative for use in existing internal combustion engines.