Sintering tests of coal ashes and measurement of thermal conductivity through ash layer were performed to obtain an understanding of ash deposition and agglomerate formation in combustion systems. The ash samples for sintering tests were preparedboth by the JIS ashing procedures and by burning in turbulent flow furnace fired 5-6kg of coal per hour to obtain fly ash. Linear shrinkage ratio of 12 ashes formed cylindrical shape were measured as an index of sintering behavior. The range of thetemperatures that shrinking started was from 700°C to 1100°C and were much lower than the Ash Fusion Temperatures. Scanning electron microscope examination provided information that ash particles have already melted at the sintering temperature. Alsothermal conductivity measurement of fly ash layer were performed. Its mean value ranges from 0.3 W/(mK) at a mean deposit temperature of 300°C to 0.45 W/(mK) at 700°C. Calculation of thickness of particulate layer and its surface temperature was carriedout using above values.
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