TABLE OF CONTENTS Frank M. Tiller, Ph.D.
M.D.Anderson Professor
Department of Chemical Engineering
University of Houston
Houston, TX
Wenfang Leu, Ph.D.
Research Scientist
Department of Chemical Engineering
University of Houston
Houston, TX
An overall filtration material balance based on a unit area is
or
where w c is total mass of dry-cake solids per unit area, ? is filtrate volume per unit area, s and s c are, respectively, the mass fraction and average mass fraction of solids in the slurry and cake, and ? is the density of filtrate. Solving for w c yields
where c is concentration expressed by mass of dry cake per unit volume of filtrate.
The value of c can be obtained from Eq. (14.1) (that is, c=w c / ? ) if it is possible to obtain the mass of solids in the cake. However, draining the slurry can often lead to difficulties in accurate determination of the cake mass. An alternative approach is to consider the cake thickness.
The cake thickness L can be related to the cake mass w c by
where ? s is the true density of the solid and ? av is the average porosity of the cake. Combining the two w c equations produces
where c L is the ratio of cake thickness L to the per-unit area filtrate volume ?. The thickness L is...
