Understanding the synergistic blending octane behavior of 2-methylfuran
KAUST DepartmentMechanical Engineering Program
Physical Science and Engineering (PSE) Division
Clean Combustion Research Center
Biological and Environmental Sciences and Engineering (BESE) Division
Chemical Engineering Program
Embargo End Date2022-12-07
Permanent link to this recordhttp://hdl.handle.net/10754/666289
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AbstractThe autoignition kinetics of hydrocarbons is an important criterion for selecting fuels for piston reciprocating engines, and it can be determined by relative performance to mixtures of alkanes, n-heptane and iso-octane, under certain standardized operating conditions. 2-methylfuran is a potential biofuel candidate, whose autoignition chemistry is markedly different from alkanes. Its octane behavior when blended with paraffins also shows a marked difference. The blending octane behavior of a fuel is characterized by its Blending Octane Number (BON). The BON of 2-methylfuran was extensively characterized in this work. 2-methylfuran's BON was mapped from experimental ignition delay times measured in a constant volume combustion chamber using established correlations. The effect on BON was studied depending on the RON of the base fuel into which 2-methylfuran was blended, as well as the quantity of 2-methylfuran blended. BON of 2-methyfuran was greater than its RON by a factor of four or more for some blends studied. BON reduced with increasing RON of the base fuel, as well as with increasing quantity of 2-methylfuran blended. A chemical kinetic model was created by integration of well validated sub-models for the blend components, and then used to explain the chemical kinetics leading to the extremely high BON values of 2-methylfuran. The synergetic anti-knock blending effect of 2-methylfuran is partially due to its physical properties leading to a greater molar fraction per volume fraction in the blend compared to iso-octane. Analysis using chemical kinetic model revealed that the chemical action behind 2-methylfuran's blending octane behavior was due to its ability to quench OH radicals which are important to the low-temperature oxidation chemistry of alkanes. This quenching effect is achieved due to the more rapid reaction rate of 2-methylfuran with OH radical compared to iso-octane, followed by the immediate conversion of the adduct shifting the equilibrium towards the product.
CitationShankar, V. S. B., Li, Y., Singh, E., & Sarathy, S. M. (2020). Understanding the synergistic blending octane behavior of 2-methylfuran. Proceedings of the Combustion Institute. doi:10.1016/j.proci.2020.06.277
SponsorsThe work at King Abdullah University of Science and Technology (KAUST) was supported by the KAUST Clean Fuels Consortium (KCFC) and its member companies.