Determination of size and porosity of chars during combustion of biomass particles

This research focused on the size and overall porosity (pore volume) of carbonaceous chars, originating from high-heating rates high-temperature pyrolysis and/or combustion biomass. Emphasis was given to torrefied biomass chars. First, char residues single particles known mass determined, based an assumed value skeletal density by comparing experimentally observed temperature-time histories with numerical predictions their burnout times. The average porosities (effective porosities) several raw were calculated be in range 92–95%. Thereafter, these deduced values input again model calculate chars other particle precursors, whose initial not known. Such sieve-classified different nominal ranges. time, besides porosity, representative time-temperature profiles aforementioned ranges also model. Biomass are highly irregular large aspect ratios and, many cases, they melt spherodize under high heating elevated temperatures. Knowledge upon extinction volatile flames, is needed for modeling heterogeneous phase. For this purpose, general agreement measurements obtained both scanning electron microscopy captured real-time high-speed, high-magnification cinematographic observations combustion. Results showed that generated examined types porous cavities. dimension rapid pyrolysis, 50–60% mid-value mesh sieves used size-classify parent particles.