Understanding the Microscopic Mechanism of Clogging of both Fibrous and Mesh Filters in Flooded-bed Wet Scrubbers

Abstract

Flooded-bed scrubbers are commonly employed in continuous miners to capture and remove dust particles at the cutting face in underground coal mines. To date, the mechanism of filter clogging as well as the evolution of pressure drop has not been well understood. In this work, clogging of filters in a relevant flooded-bed scrubber environment have been investigated in a laboratory setting by spraying a slurry onto a filter assembly while pulling the air through. Two types of filters have been investigated, including a) a multi-layer mesh filter and 2) a fibrous woven filter. Results showed that the differential pressure (or pressure drop) increased with an accumulation of clogged particles within the filter. The timed evolution of the pressure drop varied with both pore size and pore structure of the filter medium. When dust particles were much smaller than the pore size of the filter, dust particles predominantly accumulated inside the filter pack. When dust particles had comparable or larger sizes compared with the pore (or mesh) size of the filter medium, the filter was dominantly clogged at its front layers. Experimental results were compared with a modified model to account for the development of the pressure drop across the filter. The clogging of scrubber filters may be presented in two mechanisms, namely a) internal clogging and b) caking. The present result demonstrates the fundamental mechanism of clogging of dust particles within fibrous and mesh filters during dust capture and removal by flooded-bed wet scrubbers as well as other engineering applications involving in multi-phase interaction within a porous medium.