Dry coal cleaning process for high-quality coal.

Abstract

In this study, a dry coal cleaning process was developed for cleaning fine and ultrafine coal to obtain a high-quality coal. The design criterion was determined, and the operational conditions were formulated. In addition, the deash and desulfurization performances for this process were examined.A classification column was used for fine coal down to 45 microns, and a centrifugal classifier was also used for cleaning ultrafine coal particles of less than 38 microns. Some species of coal were cleaned into a high-quality coal that contained less than 1% ash content by the fluidized classification column. For finely ground coal, ash was concentrated in the ultrafine coal fraction. Pyritic sulfur was also removed to some extent in this process for fine coal particles. For most coals, the ash content could be reduced by half and the thermal recovery was up to 90%. The method of comminution was also found to play an important role in the coal cleaning process.