PRECAUTION AGAINST ASPHALTENES IN BUNKER OIL
Vessel face sometimes troubles while using residual fuels, even though fuel testing lab shows results to be in satisfactory condition.The root cause of such troubles is due to presence of asphaltenes. Asphaltenes are components of asphalt that are insoluble in petroleum naphtha but are soluble in carbon di sulfide. They are hard and brittle and are made up largely of high molecular weight poly nuclear hydrocarbon derivatives containing carbon, hydrogen, sulfur, nitrogen, oxygen and usually three heavy metals:- nickel, Iron, vanadium. As per fuel standards ISO 8217: 2010 carbon content limit is 18% m/m, whereas once the carbon content exceeds 15% m/m chances are higher for asphaltenes. Though asphaltenes are useful component of fuel oil but high level of asphaltenes can impair the combustion quality of the fuel oil, promoting increased wear and fouling of engine components. Asphaltenes cause sludge fo...