A model for pulverised fuel production in an air-swept tube mill

The grinding process of an air-swept tube mill can be modelled adequately using the selection and breakage functions approach to modelling comminution. However to model Pulverised Fuel (PF) production, all the other sub-processes that include: release of the ground product from the ball charge, internal air-classification within the mill and classification of an installed external classifier must be considered. Inefficiency in any one of these process steps can negate the overall mill capacity with little compensation from the other processes.Using industrial data from Kendal power station and data from a scaled down pilot mill at the University of Witwatersrand, a system of sub-process models have been defined and a simulator developed. We were able to simulate mill performance under different loading conditions over the entire liner life. The model details and some of the results of industrial modelling are discussed.

► Air swept mill model is developed based on PBM grinding model, virtual internal mill classifier and physical external classifier.
► A particle transport model from grind site that is dependent on liner condition is proposed.
► After parameterisation model remarkably predicts real industrial mill operation.