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ARS Home » Northeast Area » Beltsville, Maryland (BHNRC) » Beltsville Human Nutrition Research Center » Diet, Genomics and Immunology Laboratory » Research » Publications at this Location » Publication #356747
Title: Fuel composition effects on carbonyls and quinones in particulate matter from a light-duty diesel engine running biodiesel blends from two feedstocks

Author
item KASUMBA, JOHN - University Of Vermont
item Fukagawa, Naomi
item HOLMEN, BRITT - University Of Vermont

Submitted to: Energy and Fuels
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/22/2019
Publication Date: 1/22/2019
Citation: Kasumba, J., Fukagawa, N.K., Holmen, B.A. 2019. Fuel composition effects on carbonyls and quinones in particulate matter from a light-duty diesel engine running biodiesel blends from two feedstocks. Energy and Fuels. https://doi.org/10.1021/acs.energyfuels.8b03122.
DOI: https://doi.org/10.1021/acs.energyfuels.8b03122

Interpretive Summary: Several studies have linked diesel engine exhaust particulate matter (DPM) to adverse health effects. Some of the constituents of DPM could be attributed to unburned fuel, which implies that the fuels used in diesel engines are directly responsible for the toxicity associated with DPM. In this study, concentrations of a select number of target compounds (n-alkanes, PAHs, fatty acid methyl esters (FAMEs), carbonyls, and quinones) were determined in petrodiesel-biodiesel [waste vegetable oil (WVO) and soybean (SOY) feedstocks] fuel blends (0% (B00), 10% (B10), 20% (B20), 50% (B50), and 100% (B100) biodiesel by volume), lubricating oil, and biodiesel exhaust particulate matter (PM). PM was generated from a light-duty diesel engine running on a transient drive cycle, and fueled with WVO (B10,B20, B50, and B100) and SOY (B20 and B100) biodiesel fuels blended with ultra-low sulfurdiesel (ULSD) base fuel (B00). Results show that use of WVO and SOY biodiesel blends in a light-duty diesel engine is associated with significant emission reductions of some toxic and mutagenic compounds like aromatic carbonyls and quinones, but an increase in emission of other toxic compounds such as the low molecular weight aliphatic carbonyls (with less than 10 carbon atoms) which have been previously reported to induce oxidative stress in cells. Hence, differences in fuel composition alter the profile of compounds in emissions and consequently may induce variable biological effects that lead to adverse outcomes. This suggests that attention to the source of biodiesel and fuel composition may help to attenuate the adverse effects of the PM generated during combustion.

Technical Abstract: Several studies have linked diesel engine exhaust particulate matter (DPM) to adverse health effects. Some of the constituents of DPM could be attributed to unburned fuel, which implies that the fuels used in diesel engines are directly responsible for the toxicity associated with DPM. In this study, concentrations of a select number of target compounds (n-alkanes, PAHs, fatty acid methyl esters (FAMEs), carbonyls, and quinones) were determined in petrodiesel-biodiesel [waste vegetable oil (WVO) and soybean (SOY) feedstocks] fuel blends (0% (B00), 10% (B10), 20% (B20), 50% (B50), and 100% (B100) biodiesel by volume), lubricating oil, and biodiesel exhaust particulate matter (PM). Particulate matter was generated from a light-duty diesel engine running on a transient drive cycle, and fueled with WVO (B10,B20, B50, and B100) and SOY (B20 and B100) biodiesel fuels blended with ultra-low sulfurdiesel (ULSD) base fuel (B00). As expected, concentrations of individual n-alkanes (C12-C24) decreased with increasing biodiesel in the fuel for both WVO and SOY feedstocks. Only branched alkanes were detected in lubricating oil, while no n-alkanes were detected in B100 fuel samples for both feedstocks. Substituted naphthalenes were detected in B00 fuel, but no target PAHs, carbonyls and quinones were detected in B00 fuel, biodiesel fuel blends (for both WVO and SOY), or lubricating oil. Concentrations of FAMEs increased, the cis/trans isomer ratio decreased with increasing biodiesel in the fuel for both feedstocks, and no FAMEs were detected in either the neat petrodiesel fuel nor lubricating oil. Particle phase emission rates of the total aliphatic aldehydes in WVO blends increased by 0.02-2.49 ng/µgPM (56-4804%) and in SOY B20 and B100 blends were 0.05 and 0.49 ng/µgPM (106% and 1203%) higher than the petrodiesel emissions, respectively. In contrast, emission rates of target aromatic aldehydes, ketones, and quinones in both the WVO and SOY blends generally 48 decreased with increasing biodiesel in the fuel. Absence of aromatic compounds in the biodiesel fuels led to 3-50% lower quinone emissions in biodiesel exhaust PM for the B10 to B50 blends, and complete removal of quinones in the exhaust when operating on 100% neat biodiesel. FAMEs identified as the precursors to aliphatic aldehydes were polyunsaturated methyl linoleate and methyl linolenate. Mono-unsaturated methyl oleate and saturated methyl palmitate proportions relatively increased in PM compared to fuel. Both fuel endmembers contributed fuel components to exhaust, but at different mass fractions. N-alkanes in exhaust PM, originating from petrodiesel fuel, represented 0.1-0.9 of the injected fuel mass and FAMEs from biodiesel were a much smaller exhaust mass fraction (~ 10-5). Use of WVO and SOY biodiesel blends in a light-duty diesel engine therefore results in significant emission reductions of some toxic and mutagenic compounds like aromatic carbonyls and quinones, but an increase in emission of other toxic compounds such as the low molecular weight aliphatic carbonyls (with less than 10 carbon atoms) which have been previously reported to induce oxidative stress in cells. Hence, differences in fuel composition alter the profile of compounds in emissions and consequently may induce variable biological effects that lead to adverse outcomes.