Characterization of Particulate Emissions from Biodiesel using High Resolution Time of Flight Aerosol Mass Spectrometer

Abstract

In the past several decades, biofuels have emerged as candidates to help mitigate the issues of global warming, fossil fuel depletion and, in some cases, atmospheric pollution. To date, the only biofuels that have achieved any significant penetration in the global transportation sector are ethanol and biodiesel. The global consumption of biodiesel was rapidly increased from 2005. The goal of this study was to examine the chemical composition on particulate pollutant emissions from a diesel engine operating on several different biodiesels. Tests were performed on non-road diesel engine. Experiments were performed on 5 different fuel blends at 2 different engine loading conditions (50% and 75%). 5 different fuel blends were ultra-low sulfur diesel (ULSD, 100%), soy biodiesel (Blend 20% and Blend 100%) and canola biodiesel (Blend 20% and Blend 100%). The chemical properties of particulate pollutants were characterized using an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS). Organic matter and nitrate were generally the most abundant aerosol components and exhibited maximum concentration of <TEX>$1207{\mu}g/m^3$</TEX> and <TEX>$30{\mu}g/m^3$</TEX>, respectively. On average, the oxidized fragment families (<TEX>$C_xH_yO_1{^+}$</TEX>, and <TEX>$C_xH_yO_z{^+}$</TEX>) account for ~13% of the three family sum, while ~87% comes from the <TEX>$C_xH_y{^+}$</TEX> family. The two peaks of <TEX>$C_2H_3O_2$</TEX> (m/z 59.01) and <TEX>$C_3H_7O$</TEX> (m/z 59.04) located at approximately m/z 59 could be used to identify atmospheric particulate matter directly to biodiesel exhaust, as distinguished from that created by petroleum diesel in the AMS data.