Improving Fine Coal Cleaning Performance by High-Efficiency Particle Size Classification

Abstract

The presence of high-ash ultrafine particles often deteriorates the fine coal cleaning performance due to its hard-to-clean characteristics and entrainment in the clean coal product. Classification before and after have therefore become standard practice to produce a fine clean coal product. A conventional flowsheet has been considered to be adequate for several decades. However, an ever-demanding challenge for improved fine coal cleaning performance requires an increased fine particle size classification performance. This article reviewed the current fine coal classification technologies, including classifying cyclones, sieve bend, Pansep Screen, and Stack Sizer. A partition-based classification model was also discussed and adopted to simulate the fine coal classification performance. Four fine coal cleaning circuits with alternative classification technologies were compared for their respective ash-cleaning performance. The plant water within the fine coal cleaning circuit has to be recycled by proper thickening and dewatering processes. It has become an important operational concern due to its large volume, increased capital, and operational cost. A comparative study was conducted to evaluate the effects of different classification technologies on the requirements of water-recycling processes within the coal processing plants.