An experimental investigation of furfural oxidation and the development of a comprehensive combustion model

Abstract

The oxidation of furfural has been studied experimentally in a jet-stirred reactor (JSR) under fuel-lean (Φ = 0.4) and fuel-rich conditions (Φ = 2.0) in the temperature range of 650–950 K; in addition, laminar burning velocity data have been measured at T = 473 K and p = 1 bar within a wide fuel-air range. From the JSR experiments, 13 species profiles have been identified and quantified by GC–MS and GC. A detailed kinetic reaction model involving 382 species and 2262 reactions was developed by exploiting the experimental data base provided within the present work as well as experimental data reported in literature. The rate coefficients of reactions of H abstraction, H addition as well as of decomposition of furfural were calculated by quantum chemical methods at CBS-QB3 level. A general agreement was achieved when simulating the experimental data. Rate of production analysis as well as sensitivity analysis were performed to get a deeper insight into the combustion of furfural, e.g. for the jet-stirred reactor data at around 50% fuel conversion, as well as sensitivity analysis of laminar flame speeds conducted for a fuel-air ratio Φ = 0.9, 1.2, and 1.6. According to the analysis, the main consumption pathways of furfural oxidation were identified as H abstraction reactions of the R-CHO (aldehyde) group by H, OH, O, and HO 2 to produce a furfural radical (furfural-6). At pyrolysis condition, the dominant pathways within the furfural decay were found to occur via ring opening by splitting the C O bond followed by isomerization to form α-pyrone (C 5 H 4 O 2 ). Even more, the measured laminar flame speed data are well reproduced by the reaction model developed within the present work. The experimental data base as well as the developed reaction model will assist and contribute to a more detailed understanding of the combustion behavior of furfural and of furan derivatives as well.