Influence of gas velocity on cake formation and detachment

This work presents an experimental study of the influence of gas velocity d uring filtration on cake formation and its removal. The experimental data w ere obtained using a polyester felt of squared section, with an area of 0.0 225 m(2), through which the dust laden air was driven. The behaviour of the filter during filtration and cleaning was studied using four filtration ve locities (0.048; 0.067; 0.074 and 0.089 m s(-1)). For each filtration veloc ity, four cakes with different thicknesses were tested. For each cake forme d, the cleaning of the fabric was pet-formed using the reverse flow techniq ue, and the cake/fabric adhesion force was estimated. The results showed th at the cake porosity decreased and the cake specific resistance increased w ith increase in the superficial velocity of filtration. Also, for the same powder (dust) being fed, the mean particle size of the material forming the cake increased with increasing filtration velocity, probably due to partic le settling before reaching the filter. The cake/fabric adhesion force was estimated as well as the effective distance between the particle surfaces. The calculated values of both were well within the range reported in the Li terature. The former increased and the latter decreased with increase in th e superficial velocity of filtration. (C) 1999 Elsevier Science S.A. All ri ghts reserved.