Evaluation of fuel deposit and smoke emissions of Indonesian palm biodiesel B100 enhanced by BHT additive in a stationary diesel engine

Abstract As a tropical country, Indonesia has various plants that can be used as alternative energy sources, including palm oil as a biodiesel material. The use of biodiesel at a relatively high ratio continues to be encouraged by the government through various policies. The application of high concentrations of biodiesel in diesel engines needs to be supported by a series of studies to solve some of the problems that may occur and to ensure that no negative impacts occur. Oxidation stability and deposit formation are the main concerns in biodiesel use. In this study, an evaluation of B100 and B100+1000 ppm BHT fuel was carried out to determine its oxidation stability and its effect on the formation of deposits in the combustion chamber. Deposit evaluation is carried out on a stationary engine running for 70 hours (10 hours per day) with a constant load of 70% for each fuel. The addition of 1000 ppm BHT to B100 increased the oxidation stability by 171%, reduced smoke emissions by 24%, and lowered total deposit formation in the combustion chamber by 25%. A decrease in deposits was observed on the piston (32%), cylinder head (8%), and exhaust valve (23%). However, a slight increase in deposits was noted on the intake valve (11%) and injector tip, as seen from the photographic comparison. Importantly, the increase in injector tip deposits did not affect engine performance during the 70 hours of testing.