Improving the Efficiency of Fine Coal Grinding Circuits - Tarong Power Station Sitework

The objective of the research is to improve the efficiency of power station fine coal grinding circuits through the application of modelling and simulation technology. The overall project is expected to complete in 3.5 years as a PhD study program. ACARP funded the first two years (Project C15079) related to the site work conducted at Tarong Power Station, the results of which are presented in this report.

A new sampling technique has been developed to collect samples from a fully enclosed vertical spindle ball-race mill and air classifier system and that around the milling circuit. This is crucial in providing reliable data of various streams in the system for model development.

Seven surveys on the full scale fine coal grinding operation were conducted at Tarong Power Station using this sampling technique. Extensive sample processing work has been completed. This included size analysis of 217 samples, float-sink tests on 255 samples, and ash content determination on 461 samples. A new float / sink testing technique was developed to process the fine coal samples. Preliminary breakage characterisation using HGI (Hardgrove Grindability Index) tests, DWT (Drop Weight Tester) on single coal particle, and DWT on coal beds of four coal samples was conducted at the JKMRC.

This report covers the details of the sampling technique, plant surveys, and preliminary coal breakage characterisation. The observed trends of size distributions, the washability curves, the density - size relation, the density - ash content - size relation, and the correlation among the three breakage characterisation methods are presented and discussed.