ARS | Publication request: THE EFFECT OF ANTIOXIDANT ADDITION AND BIODIESEL FEEDSTOCK ON NOX EMISSIONS

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 28, 2005
Publication Date: January 30, 2005
Citation: Hess, M.A., Haas, M.J., Foglia, T.A., Marmer, W.N. 2005. The effect of antioxidant addition and biodiesel feedstock on nox emissions [abstract]. National Biodiesel Conference & Expo. p. 21.

Technical Abstract: Biodiesel is a renewable, domestically produced fuel that has been shown to reduce particulate, hydrocarbon, and carbon monoxide emissions from diesel engines. Biodiesel produced from certain feedstocks, however, has been shown to cause an increase in nitrogen oxides (NOx), which is of particular concern in urban areas that are subject to strict environmental regulations. We proposed that if specific radical reactions could be terminated, NOx production from biodiesel combustion would decrease. To test this hypothesis, we investigated the ability of antioxidants, which terminate these radical reactions, to reduce NOx levels in biodiesel exhaust. Several antioxidants added to a 20% soy biodiesel/80% diesel fuel blend (B20) at a concentration of 1000 ppm were screened using a small, minimally instrumented diesel engine to test their ability to reduce NOx emissions. The engine used for these studies was a single cylinder, direct injection, air-cooled, naturally aspirated Yanmar engine. The NO and NO2 in the exhaust stream were quantified using electrochemical sensors, and differences in NOx emissions from the combustion of B20 with and without antioxidant were compared. The addition of butylated hydroxyanisole or butylated hydroxytoluene reduced NOx emissions, but the other antioxidants tested did not have this effect. The use of biodiesel made from tallow, lard, and chicken fat was also investigated. Biodiesel made from these feedstocks was shown to reduce NOx emissions as compared to biodiesel made from soy oil.