Aerosols and Criteria Gases in an Underground Mine That Uses FAME Biodiesel Blends

Abstract

The contribution of heavy-duty haulage trucks to the concentrations of aerosols and criteria gases in underground mine air and the physical properties of those aerosols were assessed for three fuel blends made with fatty acid methyl esters biodiesel and petroleum-based ultra-low-sulfur diesel (ULSD). The contributions of blends with 20, 50, and 57% of biodiesel as well as neat ULSD were assessed using a 30-ton truck operated over a simulated production cycle in an isolated zone of an operating underground metal mine. When fueled with the B20 (blend of biodiesel with ULSD with 20% of biodiesel content), B50 (blend of biodiesel with ULSD with 50% of biodiesel content), and B57 (blend of biodiesel with ULSD with 57% of biodiesel content) blends in place of ULSD, the truck’s contribution to mass concentrations of elemental and total carbon was reduced by 20, 50, and 61%, respectively. Size distribution measurements showed that the aerosols produced by the engine fueled with these blends were characterized by smaller median electrical mobility diameter and lower peak concentrations than the aerosols produced by the same engine fueled with ULSD. The use of the blends resulted in number concentrations of aerosols that were 13–29% lower than those when ULSD was used. Depending on the content of biodiesel in the blends, the average reductions in the surface area concentrations of aerosol which could be deposited in the alveolar region of the lung (as measured by a nanoparticle surface area monitor) ranged between 6 and 37%. The use of blends also resulted in slight but measurable reductions in CO emissions, as well as an increase in NOX emissions. All of the above changes in concentrations and physical properties were found to be correlated with the proportion of biodiesel in the blends.

Effects of FAME biodiesel and HVORD on emissions from an older-technology diesel engine

“…The effects of FAME bio-diesel on NO X emissions appear to depend on a number of parameters, including engine technology, certification level (Durbin et al, 2007; Hoekman and Robins, 2012), and engine operating conditions (Muller, Boehman and Martin, 2014). The aerosols emitted by engines operated on FAME biodiesel fuels were found to be characterized by smaller median diameters than the corresponding size distributions observed for the ULSD (Bugarski et al, 2010; Bugarski et al, 2014). The formation of higher number concentrations in nucleation mode aerosols relative to ULSD were reported by Schönborn et al (2009) for several types of FAME bio-diesels.…”

“…Schönborn et al (2009) found that concentrations of nucleation mode aerosols were highest for the long-chained, fully saturated FAMEs. It is important to note that the formation of nucleation mode aerosols is strongly affected by dilution and environmental conditions, and that increase in nucleation particles was not observed in the studies conducted in underground environments where soybean oil-derived FAME biodiesels were used (Bugarski et al, 2010; Bugarski et al, 2014). …”

“…In addition, biofuels when used in high-concentration blends are perceived as a viable control strategy to reduce emissions from a variety of diesel-powered fleets (Durbin et al, 2007) as well as exposure of workers to diesel aerosols (Bugarski et al, 2010; Bugarski et al, 2014; Bugarski, Hummer and Vander-slice, 2015). …”

“…Because of their favorable effects on DPM and some gaseous emissions, biofuels — primarily FAME biodiesels — were for some time used as high-biodiesel-concentration blends or neat as a strategy to reduce diesel emissions or the exposure of workers to those pollutants (Bugarski et al, 2012). The fact that diesel engines, when fueled with FAME biodiesels in place of ULSD, emit less total DPM by mass (Yuan et al, 2007; Sappok and Wong, 2008; Gerlofs-Nijland et al, 2013) was extensively exploited to reduce concentrations of diesel aerosols and gases in underground mines (Bugarski et al, 2010; Bugarski et al, 2014). In addition, FAME biodiesels were found to have favorable effects on carbon monoxide and hydrocarbon emission reductions (Schönborn et al, 2009; Hoekman and Robins, 2012; Bugarski et al, 2014).…”

“…The fact that diesel engines, when fueled with FAME biodiesels in place of ULSD, emit less total DPM by mass (Yuan et al, 2007; Sappok and Wong, 2008; Gerlofs-Nijland et al, 2013) was extensively exploited to reduce concentrations of diesel aerosols and gases in underground mines (Bugarski et al, 2010; Bugarski et al, 2014). In addition, FAME biodiesels were found to have favorable effects on carbon monoxide and hydrocarbon emission reductions (Schönborn et al, 2009; Hoekman and Robins, 2012; Bugarski et al, 2014). It is universally accepted that those reductions in particulate, carbon monoxide and hydrocarbon emissions are primarily the result of the presence of fuel-bound oxygen in FAME biodiesel fuels (Schönborn et al, 2009).…”