Stone Fruit Seed: A Source of Renewable Fuel for Transport

Abstract

This study investigated the suitability of stone fruit seed as a source of biodiesel for transport. Stone fruit oil (SFO) was extracted from the seed and converted into biodiesel. The biodiesel yield of 95.75% was produced using the alkaline catalysed transesterification process with a methanol-to-oil molar ratio of 6:1, KOH catalyst concentration of 0.5 wt% (weight %), and a reaction temperature of 55 °C for 60 min. The physicochemical properties of the produced biodiesel were determined and found to be the closest match of standard diesel. The engine performance, emissions and combustion behaviour of a four-cylinder diesel engine fuelled with SFO biodiesel blends of 5%, 10% and 20% with diesel, v/v basis, were tested. The testing was performed at 100% engine load with speed ranging from 200 to 2400 rpm. The average brake specific fuel consumption and brake thermal efficiency of SFO blends were found to be 4.7% to 15.4% higher and 3.9% to 11.4% lower than those of diesel, respectively. The results also revealed that SFO biodiesel blends have marginally lower in-cylinder pressure and a higher heat release rate compared to diesel. The mass fraction burned results of SFO biodiesel blends were found to be slightly faster than those of diesel. The SFO biodiesel 5% blend produced about 1.9% higher NOx emissions and 17.4% lower unburnt HC with 23.4% lower particulate matter (PM) compared to diesel fuel. To summarise, SFO biodiesel blends are recommended as a suitable transport fuel for addressing engine emissions problems and improving combustion performance with a marginal sacrifice of engine efficiency.