Effect of Oxygenated Turpentine and Alpha-Pinene on Diesel Fuel Physicochemical Properties

Abstract

The increasing demand for alternative fuels has led to extensive research on bio-additives to enhance fuel performance and reduce environmental impact. This study investigates the effect of turpentine and alpha-pinene, both in pure and oxygenated forms, on the physicochemical properties of diesel fuel. The fuel properties analyzed include density, kinematic viscosity, calorific value, and cetane number. The results indicate that adding bio-additives alters the fuel's characteristics significantly. The density of the test fuels increased compared to diesel (857.72 kg/m³), with the highest density observed in alphapinene diesel at 877.06 kg/m³. Kinematic viscosity decreased with the addition of bio-additives, with oxygenated alpha-pinene diesel showing the lowest value of 2.83 mm²/s, compared to 3.32 mm²/s for diesel. The calorific value of turpentine oxygenated diesel was the highest at 44.94 MJ/kg, while alphapinene oksigenasi had the lowest at 41.09 MJ/kg. The cetane number decreased in most test fuels, with the lowest value found in turpentine diesel at 63.78, while APD had the highest cetane number of 69.46, surpassing diesel (67.3). Gas chromatography-mass spectrometry analysis revealed significant compositional changes due to oxygenation, with α-pinene content reducing from 61.81% to 32.68% and new oxygenated compounds, such as α-pinene-oxide (6.15%) and trans-verbenol (6.66%), emerging. These findings suggest that turpentine and alpha-pinene bio-additives influence fuel properties differently, with turpentine-oxygenated diesel showing the highest calorific value and alpha pinene-diesel exhibiting the best cetane number. Further research is required to evaluate their impact on engine performance and emissions.