The emission of particulate matter from ships does great harm to human health and atmospheric environment. Sulfur emission regulations also affect particulate matter emissions due to fuel change. Particulate matter (PM) emitted from low-speed, two-stroke, large-power diesel engine were studied in test-bed experiments. Experiments were conducted at 25%, 50%, 75%, and 100% load with heavy fuel oil (HFO, 3.36%m/m S) and a lighter marine diesel oil (MDO, 0.1%m/m S). The experiments revealed that using MDO could decrease the mass emission factors (EFs) of PM compared to HFO due to the fuel quality and content; however, there was no obvious difference for the number EFs of PM. The main particle when using HFO consists sulfates and bound water, and the hydrate sulfur increased with the increased engine loads. Then, another 21% is organic carbon (OC). Emission factors for inorganic elements were also studied in particles from combustion of HFO and MDO. The EFs of OC and elemental carbon (EC) were affected by engine loads, fuel type, fuel sulfur content (FSC), and combustion conditions. The size distribution of OC was similar to EC, and there were two clearly peaks for every particulate matter sample. The key effect factor for EFs of PM with marine fossil fuels was FSC.
Keywords: Emission factors; Fuel sulfur content; Marine diesel engine; Particulate matter; Size distribution.