Aerosols Emitted in Underground Mine Air by Diesel Engine Fueled with Biodiesel

Abstract

Using biodiesel in place of petroleum diesel is considered by several underground metal and nonmetal mine operators to be a viable strategy for reducing the exposure of miners to diesel particulate matter. This study was conducted in an underground experimental mine to evaluate the effects of soy methyl ester biodiesel on the concentrations and size distributions of diesel aerosols and nitric oxides in mine air. The objective was to compare the effects of neat and blended biodiesel fuels with those of ultralow sulfur petroleum diesel. The evaluation was performed using a mechanically controlled, naturally aspirated diesel engine equipped with a muffler and a diesel oxidation catalyst. The effects of biodiesel fuels on size distributions and number and total aerosol mass concentrations were found to be strongly dependent on engine operating conditions. When fueled with biodiesel fuels, the engine contributed less to elemental carbon concentrations for all engine operating modes and exhaust configurations. The substantial increases in number concentrations and fraction of organic carbon (OC) in total carbon over the baseline were observed when the engine was fueled with biodiesel fuels and operated at light-load operating conditions. Size distributions for all test conditions were found to be single modal and strongly affected by engine operating conditions, fuel type, and exhaust configuration. The peak and total number concentrations as well as median diameter decreased with an increase in the fraction of biodiesel in the fuels, particularly for highload operating conditions. The effects of the diesel oxidation catalyst, commonly deployed to counteract the potential increase in OC emissions due to use of biodiesel, were found to vary depending upon fuel formulation and engine operating conditions. The catalyst was relatively effective in reducing aerosol number and mass concentrations, particularly at light-load conditions, but also showed the potential for an increase in nitrogen dioxide concentrations at high-load modes. INTRODUCTION As of May 20, 2008, the U.S. Mine Safety and HealthAdministration (MSHA) regulation 1 limits exposures of underground metal and nonmetal miners to diesel particulate matter (DPM) to 160 g/m 3 of total carbon (TC). Improvements in mine ventilation and the curtailment of DPM and toxic gaseous emissions from existing and new diesel-powered equipment are commonly perceived as the most promising tools to meet MSHA technology forcing regulations. Although diesel particulate filter (DPF) systems are gradually becoming more utilized for controlling DPM emissions from underground mining vehicles, 2,3 their acceptance has been hindered by their relative complexity, implementation issues, and expense. Changing fuel supply from petroleum diesel to higherconcentration biodiesel blends is considered by several underground mine operators to be a viable alternative for controlling DPM emissions. The major advantages of biodiesel over petroleum-based diesel fuels with respect to DPM emissi...

Occupational Exposures to Emissions from Combustion of Diesel and Alternative Fuels in Underground Mining—A Simulated Pilot Study

“…(12,17,18,25) However, other studies have shown an increase in NO 2 or reductions in CO biodiesel emission concentrations compared to diesel fuel. (15,25) Our findings are also inconsistent with prior studies showing increased aldehyde concentrations with biodiesel use. (12,18) However, neither of the engines used in these studies used a DOC as was done in our study.…”

“…(25) Our research revealed increasing tOC and decreasing tEC concentrations associated with B75 use, consistent with previously published studies. (15,17,22,25,26) These studies used a variety of biodiesel blends, pollution control devices (or lack thereof), loading procedures, and engine configurations, all of which can influence vehicle emissions.…”

“…In general, biodiesel use appears to decrease total carbon output, but increases in organic carbon, aldehydes, and nitrogen dioxide have been reported. (12)(13)(14)(15)(16) One underground mine study showed that at idle and during operation, B20 reduced elemental carbon emissions by 14 and 31%, respectively, and B50 resulted in a reduction of 38 and 45%, respectively. (17) Conversely, other research demonstrated use of biodiesel mixtures increased aldehyde, nitrogen dioxide (NO 2 ), and organic carbon fraction concentrations.…”

“…(17) Conversely, other research demonstrated use of biodiesel mixtures increased aldehyde, nitrogen dioxide (NO 2 ), and organic carbon fraction concentrations. (15,18) In 2011, an Environmental Protection Agency (EPA)-approved natural gas/diesel (GD) fuel mixture, GDiesel, became commercially available. GD is prepared by combining diesel with natural gas, using a proprietary charged-catalytic reaction.…”

Energy supplies and future engines for land, sea, and air

“…This requires a multipollutant/multieffect air quality management strategy (Chow et al, 2010;Chow and Watson, 2011;Hidy et al, 2011;Hidy and Pennell, 2010). Transportation biofuels may reduce CO 2 emissions over their life cycles (Agusdinata et al, 2011;Hossain and Davies, 2010;Hsu et al, 2010;Meyer et al, 2011;Ou et al, 2010;Yan et al, 2010;Yu and Tao, 2009;Zhai et al, 2009), but they may result in increased gaseous and particulate pollutant emissions (Betha and Balasubramanian, 2011;Bugarski et al, 2010;Di et al, 2009; Guarieiro et al, 2009;Liu et al, 2009;Yanowitz and McCormick, 2009). Some of these emission rates may be small when engines are certified, but emission controls deteriorate over time; the more complex the after treatment, the greater is the potential for deterioration.…”