Coal Preparation » Process Control
When designing and operating coal preparation plants, it is essential to take into account potential variation in coal quality. Plant operations are also adversely affected by internal distribution biases. This ACARP funded project has studied these factors by making use of Monte Carlo simulation effects and sophisticated models of plant operations.
A survey of existing Australian coal preparation plants was undertaken to determine the magnitude of these factors. The replies indicated that a large number of plants have to deal with many different coal types, that can vary greatly in their characteristics, and that for a given coal type there can be variations in washability and sizing. Stockpiling and handling can create significant differences in plant feed sizing and hydraulic splitting within plants is often ineffective. Feed variations and maldistribution were said to result in lower throughputs and reduced efficiencies.
A simple Fortran model was initially employed to assess the impacts of variations in feed blend, fines content, slimes level, ROM coal quality, dilution and plant feed rate. A detailed model was developed by using individual unit process models, that incorporate the impact of feed rate on unit performance, and embedding them into the LIMN process simulator. The impacts of variations in coal type, coal sizing and feed rate were studied in association with variations in distribution (raw coal, DMC pairs, spiral units).
The results include consideration of the factors that influence a justifiable level of overdesign, by looking at capacity and production losses. Internal biases to different circuits can have a large impact on plant results, with dense medium cyclones showing some poor performances when overloaded due to maldistribution. Capital costs of overdesign have been considered in relation to the revenue losses due to production constraints.
When designing and operating coal preparation plants, it is essential to take into account potential variation in coal quality. Plant operations are also adversely affected by internal distribution biases. This ACARP funded project has studied these factors by making use of Monte Carlo simulation effects and sophisticated models of plant operations.
A survey of existing Australian coal preparation plants was undertaken to determine the magnitude of these factors. The replies indicated that a large number of plants have to deal with many different coal types, that can vary greatly in their characteristics, and that for a given coal type there can be variations in washability and sizing. Stockpiling and handling can create significant differences in plant feed sizing and hydraulic splitting within plants is often ineffective. Feed variations and maldistribution were said to result in lower throughputs and reduced efficiencies.