Coal breakage characterisation – Part 3: Applications of the multi-component model for HGI prediction and breakage simulations

Abstract

A new method was developed to infer the HGI (Hardgrove Grindability Index) values from the product fineness indicator, t10, predicted by the multi-component breakage model. A total of 41 sets of JKFBC (JK Fine-particle Breakage Characteriser) tests, on coals from Australia and China, plus ores containing various minerals and a clinker, were used to validate this method. The JKFBC and the multi-component breakage model have the potential to improve or replace the traditional HGI test. A new coal grindability index can be generated from the multi-component model parameters. As the major error sources associated with the traditional HGI test have been removed in this new approach, superior repeatability and reproducibility can be expected. More work is recommended in this area to validate this novel approach and to identify its limitations.Simulations were conducted by employing the multi-component breakage model to demonstrate the effects of particle size and density on pulverised fuel (PF) grinding; to troubleshoot the PF production problems related to the coal properties; and to elucidate the observed trend of the non-linear phenomenon of the HGI effect on the PF milling capacity; whereby a 10 unit reduction in HGI from 50 to 40 requires four times more energy than a 10 unit HGI reduction from 90 to 80 in order to achieve the same PF production rate.