Effects of substitution on counterflow ignition and extinction of C3 and C4 alcohols
KAUST DepartmentClean Combustion Research Center
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AbstractDwindling reserves and inherent uncertainty in the price of conventional fuels necessitates a search for alternative fuels. Alcohols represent a potential source of energy for the future. The structural features of an alcohol fuel have a direct impact on combustion properties. In particular, substitution in alcohols can alter the global combustion reactivity. In this study, experiments and numerical simulations were conducted to investigate the critical conditions of extinction and autoignition of n-propanol, 1-butanol, iso-propanol and iso-butanol in non-premixed diffusion flames. Experiments were carried out in the counterflow configuration, while simulations were conducted using a skeletal chemical kinetic model for the C3 and C4 alcohols. The fuel stream consists of the pre-vaporized fuel diluted with nitrogen, while the oxidizer stream is air. The experimental results show that autoignition temperatures of the tested alcohols increase in the following order: iso-propanol > iso-butanol > 1-butanol ≈ n-propanol. The simulated results for the branched alcohols agree with the experiments, while the autoignition temperature of 1-butanol is slightly higher than that of n-propanol. For extinction, the experiments show that the extinction limits of the tested fuels increase in the following order: n-propanol ≈ 1-butanol > iso-butanol > iso-propanol. The model suggests that the extinction limits of 1-butanol is slightly higher than n-propanol with extinction strain rate of iso-butanol and iso-propanol maintaining the experimentally observed trend. The transport weighted enthalpy (TWE) and radical index (Ri) concepts were utilized to rationalize the observed reactivity trends for these fuels.
CitationEffects of substitution on counterflow ignition and extinction of C3 and C4 alcohols 2016 Energy & Fuels
SponsorsThis work was performed by the Clean Combustion Res earch Center with funding from King Abdullah University of Science and Technology (KAUS T) and Saudi Aramco under the FUELCOM program. Research reported in this publicat ion was also supported by competitive research funding from KAUST. The research at the Un iversity of California at San Diego was supported by UC Discovery/West Biofuels, LLC Grant # GCP06(10228. We thank Professor Kalyanasundaram Seshadri, Samah Y. Mohammed and Nou r Atef for their contribution.
PublisherAmerican Chemical Society (ACS)
JournalEnergy & Fuels