Ash deposits reduce heat transfer rates to furnace walls, superheat tubes, and other heattransfer surfaces in coal-fired power plants. Thermal conductivity and emissivity are the twodeposit properties that influence strongly this heat transfer. These properties are thought todepend mainly on the microstructure of the deposit. To estimate the thermal conductivity, themicrostructure of two sample ash deposits was quantitatively characterized using image analysistechniques. A ballistic deposition model was adopted and modified to simulate the depositstructure having the particle sintering. Model inputs include fly ash size distribution, particleviscosity, and particle rolling, which are chosen to match boiler operations and coal quality. Themicrostructure of the simulated deposits and the sampled deposits are quantitatively comparedusing a variety of structural parameters. Both sampled and simulated deposits are coincident interms of the structural parameters.
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