Fragmentation of heated droplets of coal-water slurries containing petrochemicals

Abstract

This research presents experimental findings on the fragmentation of droplets of coal-water slurries containing petrochemicals heated on a substrate (300–600 °C), in an air flow (450–550 °C), and in a tubular muffle furnace (500–700 °C). The fuels were composed of water, coal, coal processing waste (filter cakes), used industrial turbine oil, sawdust, nut shells, and stabilizers (neonol, starch, and tween). Before ignition, heated droplets behaved in three possible ways: gradual shrinking due to moisture evaporation; significant surface deformation when subjected to heating and droplet breakup with large fragments separating from it; full breakup of a droplet into small fragments. We recorded the droplet breakup delay times and integral characteristics of secondary fragments (number, size, and surface area) in comparison with the same parameters of the initial droplet. We also established the impact of a set of factors (temperature, heating scheme, and component composition of droplets) on the above characteristics. Approximations were obtained for the dependences established to be used for mathematical modeling. Finally, the findings were compared with the earlier established characteristics of similar processes studied in experiments with emulsion droplets and two-component immiscible droplets containing liquid combustible and noncombustible components.