Comparative study on soot characteristics of non-swirling and swirling inverse diffusion iso-octane flames with biofuel 2,5-dimethylfuran addition

Due to the heavy consumption of the fossil fuels in the transportation sector and the furnace factory, a large amount of soot is discharged and seriously threatened the environment and the human health. The present work focuses on examining the characteristics of soot produced from iso-octane/2,5-dimethylfuran (DMF) non-swirling and swirling inverse diffusion flames (IDFs). Morphology, nanostructure, graphitization and oxidation reactivity of nascent soot particles from 100% iso-octane, 50% isooctane/50% DMF and 100% DMF IDFs were investigated by using high resolution transmission electron microscopy, X-ray diffraction, and thermogravimetric analysis, respectively. The effect of swirling on the soot characteristics was discussed. Results demonstrate that the nascent soot from pure iso-octane flames shows the morphology with liquid-like deposition and turbostratic nanostructure, while the soot from pure DMF displayed more primary particle with the nanostructure contained by many well-organized lattice fringes. Because the mixability of air and fuel under the action of swirling is higher than that of non-swirling condition, the soot particles from swirling conditions reveal more ordered nanostructure with longer fringe length and lower fringe tortuosity, as well as higher soot graphitization and lower oxidation reactivity. (C) 2020 Energy Institute. Published by Elsevier Ltd. All rights reserved.