Particle Size Distribution as a Nonindependent Variable Affecting Pulverized-Coal Burnout in Coal-Fired Power-Plant Boilers

The particle size distribution (PSD) is critical for pulverized-coal combustion in coal-fired power-plant boilers. However, the PSD might not necessarily be an independent variable in combustion analysis. Using industrial-scale combustion tests in a coal-fired power plant, this work aimed to explore the relationship between the PSD of pulverized coal and coal properties and to understand the role of coal properties in the PSD impacting coal burnout. The results showed that the 110–480-μm fraction of pulverized coal strongly affects coal burnout and that this coarse fraction is closely correlated with coal properties. Therefore, it was concluded that the PSD and its influence on coal burnout are essentially dependent on coal properties. The synthetic index F pp, combining the proximate and petrographic analyses, has a significantly high correlation with the 110–500-μm fraction of pulverized coal. Thus, F pp can be used to predict the coarse fraction of pulverized coal from coal mills. Additionally, maceral analysis showed that coal pulverization can lead to the partitioning of macerals.