Loading identical contents of sodium and quartz into different ash-removed coals to elaborately investigate the real effects of coal particle combustion on the emission behavior of PM10

This contribution reports the real effects of coal particle combustion on the emission behavior of particulate matter (PM) with aerodynamic diameters of <10 µm (PM10). To do this, two coals, i.e., the ZD subbituminous coal and the PDS bituminous coal, were acid-washed to remove most inorganic compositions. The acid-washed coals were then loaded with identical contents of organically-bound Na and excluded quartz to produce the Na + Si loaded coals, which were then combusted via a high temperature drop tube furnace (DTF) at 1500 °C in air to collect the inorganic PM10 for subsequent analyses. Burning the Na + Si loaded coals with simplified and identical mineral compositions enabled us to purposely study the real effects of coal particle combustion on PM10 emission. The results demonstrate the trimodal distributions of PM10 produced from the Na + Si loaded coals containing such simple inorganic compositions. The combustion of PDS Na + Si loaded coal seems to form more PM than that of ZD Na + Si loaded coal. In contrast to the combustion of the ZD subbituminous coal, more Na and SiO are vaporized to form more PM0.5 due to the higher peak burning temperature of the PDS bituminous coal during the stage of volatile matter combustion, meanwhile, more coalescence of quartz occurs due to its melting point being decreased by the heterogeneous condensation of Na, causing more PM2.5-10 being generated from the combustion of the PDS bituminous coal. When the PDS Si-only loaded coal is burned, the coalescence of quartz particles should be suppressed due to the lack of condensed Na. In addition, its lower char burning temperature can also suppress the coalescence of fine quartz particles, forming less PM2.5-10 compared with the combustion of the ZD Si-only loaded coal. The results suggest that both the stages of volatile matter combustion and char combustion of coal particles can affect the emission of PM10.