In the brown coal liquefaction (BCL) process, a solvent de-ashing technique has been adopted to remove ash and heavy preasphaltenes from CLB (Coal Liquid Bottom, bp>420℃) as insoluble solids by gravity settling. This paper reveals the effects of de-ashing conditions on the concentration of the solids in a settler using a continuous de-ashing system and introduces an empirical equation for suitable de-ashing operation.
