Reactivity Trends in Furan and Alkyl Furan Combustion

Abstract

A systematic study of the ignition behavior of furan and the substituted furans 2-methyl furan (2-MF) and 2,5dimethyl furan (DMF) is presented. Ignition delay times are measured over a temperature range from 977 to 1570 K and pressures up to 12 atm for lean, stoichiometric, and rich mixtures of fuel, oxygen, and argon. It is found that when the equivalence ratio ϕ, the argon-to-oxygen ratio D, and pressure p are kept constant over a range of temperatures T, DMF generally has the longest, while 2-MF has the shortest, ignition delay times, and furan shows intermediate reactivity. Ignition delay times decrease with increasing equivalence ratios, except for DMF, which does not show a conclusive trend over the temperature range investigated. The experimental data are also found to agree with published ignition data, showing differences in some cases partly related to disparities in endwall and sidewall ignition measurements. The ignition delay times of 2-MF and DMF are compared to predictions using furan chemical kinetic models by Sirjean et al. 1 and Somers et al. 2 The models show qualitatively that DMF has longer ignition delay times than 2-MF under similar conditions of ϕ, D, p, and T, as revealed by the experiments. Quantitatively, the model predictions agree with experimental data at conditions similar to those used in their development, and deviations from experiment at other conditions are mostly related to unmatched temperature sensitivities over a wider temperature range, revealed by varying pressure and reduced dilution. The reported experimental data set contributes toward further understanding and improved modeling of the combustion of furans, a promising class of alternative fuels.

Recent Trends in the Production, Combustion and Modeling of Furan-Based Fuels

“…Another effort by Eldeeb and Akih-Kumgeh [25] involved the investigation of the comparative ignition behavior between 2,5-DMF and 2-ethylfuran (2-EF). The results of 2,5-DMF and 2-EF ignition delay time measurements revealed much shorter ignition delay times for 2-EF, and therefore, 2,5-DMF was established as the least reactive furan, combining these results with the result of a previous study [24]. Moreover, the findings indicate a universal reactivity behavior between dimethyl and ethyl isomers of cyclic compounds, based on the results of another study by Eldeeb and Akih-Kumgeh [197] that compared the ignition delay times of 2,5-DMF and 2-EF, along with another reactivity trend comparison between 1,3-dimethylcyclohexane and ethylcyclohexane, which revealed a similar trend.…”

“…Eldeeb and Akih-Kumgeh [24] used their ignition delay time measurements for 2,5-DMF and 2-MF for comparison with chemical kinetic models by Sirjean et al [10] and Somers et al [9]. The comparative reactivity trend was qualitatively captured by both models, indicating that 2,5-DMF is less reactive than 2-MF.…”

“…A number of studies focused on comparative reactivity trends among furans and alkyl furans through ignition delay time measurements [24,25,[197][198][199][200]. One of the leading efforts in this direction was a study by Eldeeb and Akih-Kumgeh [24], which systematically investigated the ignition behavior of furan, 2-MF and 2,5-DMF.…”

“…One of the leading efforts in this direction was a study by Eldeeb and Akih-Kumgeh [24], which systematically investigated the ignition behavior of furan, 2-MF and 2,5-DMF. Measurements of ignition delay times were performed in a shock tube for fuel/O 2 /Ar mixtures over a temperature range of 977-1570 K, pressures of 2-12 atm and equivalence ratios of 0.5-2.0.…”

“…Another group of chemical kinetic model validation studies focused on the validation of models against ignition and concentration data for multiple furans and tetrahydrofurans [24,29,139,155,198,227]. Eldeeb and Akih-Kumgeh [24] used their ignition delay time measurements for 2,5-DMF and 2-MF for comparison with chemical kinetic models by Sirjean et al [10] and Somers et al [9].…”