Automatic Control of Coal Flotation and Dewatering Processes

Abstract

Coal preparation plant operators often do not optimize the flotation and dewatering processes. In order for these processes to operate efficiently, the equipment should be adjusted after every change in feed rate or quality. Unfortunately, neglect of the final coal processes causes processing additives and coal to be wasted and in some cases, unnecessary outages of the entire cleaning plant. Consequently, revenues decrease. A control system for the froth flotation and dewatering processes was developed and is now operational in four bituminous coal preparation plants owned by Consolidation Coal Company (CONSOL Inc.). The system controls 1) the flotation tailings ash content via flotation reagent adjustment. 2) the froth cell level by adjusting the tailings dart valve positioning, and 3) the vacuum disc filter level via filter rotational speed and flocculant feed rate adjustments. Central to the system operation is a newly developed sensor. This innovative optoelectronic sensor is used to estimate the amou...