| Summary: | 碩士 === 國立臺灣大學 === 化學工程學系 === 86 === As a first step to study the mechanism of cake filtration of deformable
particles, the compression and deformation behaviors of Ca-alginate gel
particles bed under mechanical loading and hydraulic drag in a particles
bed were conducted. Experimental results show that progressive decreases in
the bed height, volume, and porosity of the bed took place gradually as the
pressure on the bed was increased, with the particles being deformed into
flattened dodecahedrons.
Cake filtration experiments of S. cerevisiae and PMMA were conducted to
examine the structure of flux limiting layer formed by deformable particles.
Effect of particle deformation due to friction drag and mass of cake on the
reduction of porosity is studied to examine how this variation leads to the
increase in filtration resistance. Results show that as the cake formed by
deformable gel particles exhibits a rapid increase in flow resistance or
decrease in porosity due to area contact between particles,a flux limiting
layer, resistant material is formed next to the filter medium
during filtration.
A dynamic analysis proposed by Lu and Hwang (1993) was modified to
investigate cake formation in cake filtration of deformable particles by
taking the transient effect of cake compression and the effect of area
contact between particles into consideration. The simulated results agree
well with the experimental data.
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