LAUSR

Abstract Marine lubricants’ ability of dispersing Heavy Fuel Oil (HFO) can be quantitatively observed and evaluated with an efficient and economic method: heating capillary video microscopy. Effects on HFO dispersion included those of surfactants’ type, over-basing level and temperature, while also discussing what Carbon chain lengths can be expected to perform better. For same-chain-length surfactants, samples with higher concentration of base showed lower ability of dispersing HFO. Samples with medium surfactants chain length and no overbased particles, dispersed up to 81% of the HFO at 100 °C in 200 seconds. Dispersion of HFO happened mostly at the beginning of its introduction to lubricant oils, while undispersed HFO remained almost intact even after days. Discussion is provided on the possible asphltene dispersing action of surfactants, reflecting on Total Base Number (TBN) and surfactant chain length, which are important parameters in optimizing lubricant formulations. Graphical Abstract