Comparison of filter smoke number and elemental carbon from thermal optical analysis of marine diesel engine exhaust

The interest on contribution of shipping to global warming and especially on polar ice melting has increased. The International Maritime Organization is working toward reporting and estimation of black carbon emissions from shipping. The filter smoke number method is discussed as one possible candidate for onboard determination of black carbon/soot concentration of the engine exhaust gas, and it has recently been considered as one of the best candidates for further evaluation in the International Council on Clean Transportation 4th workshop on marine black carbon emission. Proven, standardized technology and small size and simple operation of the filter smoke meter make it a potential choice for actual onboard use. In our study, we evaluated the validity of the filter smoke number method for measuring soot emission by looking at correlations between the filter smoke number and elemental carbon analyzed using thermal optical transmittance analysis. Until now the conversion of the filter smoke number to black carbon /soot emission has been performed with equations derived from high-speed engines operating with distillate fuels. We introduce optimized calculation parameters for filter smoke number to black carbon/soot conversion, which are derived from light and heavy fuel oil measurements. These new parameters can be utilized with improved accuracy for the estimation of the black carbon emission from filter smoke number measurement with marine fuel qualities.