Experimental investigation of fuel properties and engine operation with natural and synthetic antioxidants added to biodiesel
Gediz Uğuz, Abdülvahap Çakmak, Carlos da Silva Bento, Nalan Türköz Karakullukçu
Abstract
Abstract yClove (CEO) and thyme (TEO) essential oils were added to a colza biodiesel–diesel blend (B20) as natural antioxidants, and butylated hydroxytoluene (BHT) was added as a synthetic antioxidant, at 3000 ppm concentration. Fuel properties, instrumental characterizations, engine performance, combustion characteristics, and emissions of the blends were analyzed. Fourier Transform Infrared Spectroscopy (FT-IR) spectra showed that the transmission intensities of samples increased with antioxidant addition. B20 and B20–antioxidant blends were subjected to engine tests under various loads and a fixed engine speed of 1500 rpm to determine the combustion, performance, and emissions. Engine tests revealed that antioxidants caused an increase in specific fuel consumption by 0.9–2.4% and a drop of 1.1–2.2% in thermal efficiency compared to B20. Antioxidants increased in hydrocarbons HC emission due to their oxidation-inhibitive nature, while they provided substantial improvements in smoke opacity and CO2 emission. BHT reduced NO emissions by 21% compared to B20 fuel without antioxidants. BHT was more successful in curbing NO emissions but caused an average increase in CO emissions of 3.68%. CEO-blended fuel offers better engine performance and emissions improvement than TEO-blended fuel.Keywords: Biodieselclove oilengine testnatural antioxidantsynthetic antioxidantthyme oil AcknowledgmentsThe authors thank TBE Agricultural Biodiesel Energy Company in Kocaeli, Turkey, for providing colza biodiesel and assisting in the analysis. In addition, the authors thank Dr Tuna DEMİRCİ for the FT-IR analysis and İbrahim Ethem OLUKÇUOĞLU (Head of Library Department of Ondokuz Mayıs University) for literature research support.Author contributionsAll authors contributed equally to the study conception and design. All authors read and approved the final manuscript.Disclosure statementNo potential conflict of interest was reported by the authors.