High Ash Fine Coal Dry Cleaning and Stability of Shallow Bed Dense-Phase Gas–Solid Separation Fluidized Bed

Abstract

Fine coal dry separation technology has been one of the international research hotspots in the field of coal preparation. This article proposes the shallow bed dense-phase gas–solid fluidized bed separation technology to remove gangue from the high ash fine coal. According to the criterion of center pressure drop, the CP value can be finally reduced by reducing the bed height, H, to decrease the bed pressure drop, ΔPB, under the condition of a fixed gas distributor pressure drop, ΔPD. A fluidized bed of uniform and stable density was formed. The medium of 33% fine particles showed a better performance in −6+3 mm, −3+2 mm, and −2+1 mm fine coal separation than the medium of different fine particles content by ash segregation. A 100 mm bed height with a medium of 33% fine particles was selected to separate −6+3 mm fine coal. The ash content of cleaned coal reached 9.66% under the optimized conditions, whereas the clean coal yield reached more than 77.75%. For −3+2 mm fine coal, the cleaned coal yield was 82.59%, the ash content of clean coal was 10.93%, and the deash rate could reach 51.96%. The shallow bed dense-phase gas–solid fluidized bed exhibited poor liquidity and high viscosity under conditions of low gas velocities. The shallow bed dense-phase gas–solid fluidized bed (100 mm bed height) with medium containing 33% fine particles can separate the −6+2 mm fine coal.