Sources of variance in BC mass measurements from a small marine engine: Influence of the instruments, fuels and loads

Publication date: June 2018
Source:Atmospheric Environment, Volume 182
Author(s): Yu Jiang, Jiacheng Yang, Stéphanie Gagné, Tak W. Chan, Kevin Thomson, Emmanuel Fofie, Robert A. Cary, Dan Rutherford, Bryan Comer, Jacob Swanson, Yue Lin, Paul Van Rooy, Akua Asa-Awuku, Heejung Jung, Kelley Barsanti, Georgios Karavalakis, David Cocker, Thomas D. Durbin, J. Wayne Miller, Kent C. Johnson
Knowledge of black carbon (BC) emission factors from ships is important from human health and environmental perspectives. A study of instruments measuring BC and fuels typically used in marine operation was carried out on a small marine engine. Six analytical methods measured the BC emissions in the exhaust of the marine engine operated at two load points (25% and 75%) while burning one of three fuels: a distillate marine (DMA), a low sulfur, residual marine (RMB-30) and a high-sulfur residual marine (RMG-380). The average emission factors with all instruments increased from 0.08 to 1.88 gBC/kg fuel in going from 25 to 75% load. An analysis of variance (ANOVA) tested BC emissions against instrument, load, and combined fuel properties and showed that both engine load and fuels had a statistically significant impact on BC emission factors. While BC emissions were impacted by the fuels used, none of the fuel properties investigated (sulfur content, viscosity, carbon residue and CCAI) was a primary driver for BC emissions. Of the two residual fuels, RMB-30 with the lower sulfur content, lower viscosity and lower residual carbon, had the highest BC emission factors. BC emission factors determined with the different instruments showed a good correlation with the PAS values with correlation coefficients R2 >0.95. A key finding of this research is the relative BC measured values were mostly independent of load and fuel, except for some instruments in certain fuel and load combinations.



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