Simulation of operational behaviour of patchily regenerated, rigid gas cleaning filter media

Particle removal from hot process gases is frequently accomplished with reg enerable ceramic filters. When regenerating such media periodically, the du st cake may be detached from parts of the filter surface while other region s remain intact ('patchy cleaning'). The filtration process depends on how these patterns of incomplete regeneration evolve over a number of cycles, h ow they change the build-up of the new cake, and how they affect the pressu re drop. A two-dimensional quasi stationary flow model is used to predict p ressure drops as a function of regeneration efficiencies and regeneration p atterns, taking into account the finite thickness and flow resistance of th e medium itself. The effect of non-uniform cake build-up on the pressure ri se during a filter cycle is also modelled for a partially regenerated filte r. The calculations prove that the pressure drop rises faster for lower reg eneration efficiencies and that also cycle times become briefer with lower regeneration efficiency. It can also be shown, that the regeneration patter n only influences the pressure drop curve at the very beginning of the filt ration cycle but does not influence the filtration cycle times. (C) 1999 El sevier Science S.A. All rights reserved.