GRAVITY-DRIVEN THICKENING IN A LONG, VERTICAL TUBE

The problem of gravity-driven thickening of a dispersion in a long, ve rtical tube of diameter larger than the dimensions of the dispersed ph ase particles has been treated. Inflow of the suspension takes place t hrough the porous tube wall and suspension is pumped away both at the upper and lower ends. A theoretical analysis of the problem is given. A material balance over a differential element spanning the cross-sect ion leads to a model equation that has been solved analytically and nu merically. The behaviour of the model as a function of various paramet ers, such as the axial dispersed phase concentration profile and the r atio of flows through the upper and lower pumps, is discussed. Compari son with the experimental results obtained in an industrial system sho ws good agreement. Copyright (C) 1996 Elsevier Science Ltd