Prediction of Pulverizer Performance
This project examined the mill test data from ACIRL’s pilot scale vertical spindle mill on 96 coals. A total of 360 mill tests, conducted under a wide range of throughputs, roll pressures and classifier settings, were included into the data set.
The mill performance of maceral groups or microlithotypes was assumed to be additive, that is, each maceral group or microlithotype behaved independently and a size fraction of the product PF was the mass weighted sum of the petrographic components of that size fraction. Based on this assumption it was possible to determine the size distribution of the product PF for a wide range of milling conditions based solely on petrographic analysis. Microlithotypes were not determined directly but were estimated from the maceral analysis. The size distribution of individual maceral groups or microlithotypes can also be estimated based on developed correlations. Size distribution determined from petrographic analysis proved to be a better estimate than that obtained determined from the HGI.
Mill power can also be estimated from petrographic analysis, but the HGI is a better predictor of mill power.