(199f) Combustion and Emission from Biodiesel/Diesel and Alcohol/Diesel Surrogate Flames

Authors: 
Ghiassi, H., University of Utah
Lighty, J. S., Boise State University
Jaramillo, I., University of Utah

With the growing interest and utilization of oxygenated fuels as alternatives or additives to petroleum-derived fuels, there are a number of critical aspects about these fuels that need to be studied and well understood. The present study focuses on analyzing the impact of two main oxygenated fuels—alcohol and ester—on the sooting tendency and the soot oxidative reactivity, two important aspects of particulate matter (PM) emissions. Biodiesel is an ester content fuel known to improve the combustion properties and to reduce PM emission from conventional diesel fuel. Methyl decanoate (biodiesel surrogate) was added to n-dodecane (diesel surrogate) to understand the effect of the ester moiety in the mixture of biodiesel/diesel surrogate. The effect of addition of alcohol on the sooting behavior of n-dodecane was also investigated by using n-butanol. A two-stage burner was used to characterize the oxidation of soot for different mixtures and to isolate the soot oxidation from the soot formation process. A scanning mobility particle sizer (SMPS) was used to measure the soot particle size distributions (PSDs) at different heights in the flame during oxidation, and soot oxidation rates were estimated using the PSDs. Temperature profiles were measured along the centerline of the flame for the fuel mixtures. Gaseous species such as O2, CO, CO2, H2 were measured by online gas chromatography and used to validate a detailed kinetic model which predict the OH concentration in the secondary flame. Soot oxidation rates were calculated by Neoh expression and compared with experimental data.