Predicting the slagging potential of co-fired coal with sewage sludge and wood biomass

Operational issues, such as slagging, fouling and corrosion of boilers during co-firing are yet to be fully understood. A numerical slagging index (NSI) to predict the slagging potential of coals and coal blends has been developed by some of the present authors, and this has been successfully validated with some Australian bituminous coals. In this paper, the NSI has been modified in order to predict the slagging potential of coal and biomass blends. The modified slagging index (MSI) considers the effects of the ash properties, the ash content and the heating values of the individual fuels in predicting the slagging potential of each blend. The results of the MSI predictions on coal/sewage sludge and coal/saw-dust blends produce a very good correlation with the reported experimental data. It has been observed that the ash content and the composition of the ash in the blends can be used to predict the behaviour of the ash mixture according to the proportional weights of the individual fuels.