On-line Estimation Of Plant Feed Washability

Plant feed washability determines the yield achievable for given product ash levels after cleaning. Plant feed washability can vary with time due to variations in feed coal characteristics as coal is sourced from different seams, different locations within a seam, and due to out of seam dilution. Hence, it is highly desirable to monitor the plant feed washability to optimise the cut-point of individual dense medium cyclone (DMC) operation.

This project has successfully developed the system for the on-line estimation of the plant feed washability through the activities listed below:

· Developed algorithm and software for the washability estimation;

· Carried out the evaluation of the method for the washability estimation using simulated cases studies;

· Implemented on-line sensors for medium densities and the DMC product yield in a coal preparation plant;

· Carried out plant sampling and float/sink testing of the sampled coal, and compared the float-sink washability data with those from on-line estimation; and

· Improved the determination of mass flowrates on screens.

Simulated cases have been used to thoroughly evaluate the performance of the method for the washability estimation under practical conditions. Three plant-based experiments were carried out to test the performance of the method and the approach for improving the yield monitoring.  A number of major findings were derived from these simulations and plant-based experiments.