Alcohols, such as butanol, are a class of molecules that have been proposed as a bio-derived alternative or blending agent for conventional petroleum derived fuels. The structural isomer in traditional " bio-butanol" fuel is 1-butanol, but newer conversion technologies produce iso-butanol and 2-butanol as fuels. Biological pathways to higher molecular weight alcohols have also been identified. In order to better understand the combustion chemistry of linear and branched alcohols, this study presents a comprehensive chemical kinetic model for all the four isomers of butanol (e.g., 1-, 2-, iso- and tert-butanol). The proposed model includes detailed high-temperature and low-temperature reaction pathways with reaction rates assigned to describe the unique oxidation features of linear and branched alcohols. Experimental validation targets for the model include low pressure premixed flat flame species profiles obtained using molecular beam mass spectrometry (MBMS), premixed laminar flame velocity, rapid compression machine and shock tube ignition delay, and jet-stirred reactor species profiles. The agreement with these various data sets spanning a wide range of temperatures and pressures is reasonably good. The validated chemical kinetic model is used to elucidate the dominant reaction pathways at the various pressures and temperatures studied. At low-temperature conditions, the reaction of 1-hydroxybutyl with O 2 was important in controlling the reactivity of the system, and for correctly predicting C 4 aldehyde profiles in low pressure premixed flames and jet-stirred reactors. Enol-keto isomerization reactions assisted by radicals and formic acid were also found to be important in converting enols to aldehydes and ketones under certain conditions. Structural features of the four different butanol isomers leading to differences in the combustion properties of each isomer are thoroughly discussed.
|Original language||English (US)|
|Number of pages||28|
|Journal||Combustion and Flame|
|State||Published - Jun 2012|
Bibliographical noteFunding Information:
The US Department of Energy, Office of Vehicle Technologies and Office of Basic Energy Sciences supported the portion of this work performed at LLNL, and the authors thank program managers Kevin Stork and Wade Sisk. Research at LLNL was performed under the auspices of the US Department of Energy under Contract DE-AC52-07NA27344. The work at RWTH Aachen is part of the Cluster of Excellence “Tailor Made Fuels from Biomass”, which is funded by the Excellence Initiative by the German federal and state governments to promote science and research at German universities. The work in Bielefeld was supported by Deutsche Forschungsgemeinschaft under contract KO1363/18-3. S.V. gratefully acknowledges support from the Alexander Von Humboldt (AvH) Foundation. S.M.S. acknowledges fellowship support from NSERC of Canada.
- Alcohol combustion
- Butanol isomers
- Chemical kinetic modeling
- Reaction rate rules
ASJC Scopus subject areas
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology
- Physics and Astronomy(all)