PATCHY CLEANING OF RIGID GAS FILTERS .1. A PROBABILISTIC MODEL

Filtration with ceramic filters is a major technology for removal of p articulate emissions at high temperatures. In combination with injecti on of a dry sorbent ('dry scrubbing'), ceramic filters are also used t o remove gaseous contaminants. Such filters are regenerated by applica tion of a reverse pulse of cleaning gas; this frequently leads to part ial or 'patchy' cleaning rather than complete simultaneous cake detach ment. This pager presents a probabilistic model to describe, as a resu lt of patchy cleaning, the area distribution of cake patches with diff erent ages, the thickness distribution, the velocity distribution, and the pressure drop history. A generalised probability distribution has been derived. Different modes of patchy cleaning have been proposed a nd can be simulated by changing the value of a weighting factor contai ned in the generalised distribution. Incorporated into a fixed-bed rea ction model, this model makes it possible to examine the effect of pat chy cleaning on dry scrubbing of acid gases in filter cakes. Copyright (C) 1996 Elsevier Science Ltd