A study on the compression of compressible soft particles and filtration of its slurries
Date Issued
2005
Date
2005
Author(s)
Lin, Yu-Li
DOI
zh-TW
Abstract
The performance of the filtration of the compressible soft particle slurries is systematically studied in the following three aspects:
First of all, the uni-axial compression of a single compressible(volume variable) or incompressible(volume invariable) soft particle without or with surrounded by other particles are studied to obtain the compression models for characterizing the properties of the soft particles in a deformation course. It is shown that the incompressible soft particle expands more significantly during compression and therefore interacts with the surrounding ones more effectively than the compressible soft particle. The results calculated by the models can properly describe the compression behaviors of the soft particles as well.
Secondly, a method of dynamic analysis based on modified Ergun equation, which considering about the volume variation of the particles, was proposed to evaluate the structural and hydro-dynamic behaviors of the compressible soft particles bed under a constant pressure-drop or a constant rate operation. Experimental results show different mechanisms for bed-height variation of the constant pressure-drop and constant rate operations. The results of dynamic analysis indicate that without considering the volume variation of the particles, reasonable estimations of the properties of the compressible particle beds are not possible.
In the third portion, compressible Sephadex and Ca-alginate particles are adopted for the cake filtration experiments under a constant pressure(CPF) and a constant rate(CRF) operation. The method of dynamic analysis of cake filtration proposed by Lu et al.(2001b) is modified by the consideration of the volume variation of the particles to investigate the local cake properties of compressible soft particles. From the experimental results, the filtration curve shows various stages due to the deformability of compressible particles. Results obtained by dynamic analysis show that although the cake structures obtained by CPF and CRF differ obviously, the relations between the local porosity and the solid compressive pressure of the two operations are approximately the same. The verification of the cake characteristic values obtained by dynamic analysis by the estimation of the CPF filtration curve agrees with the experimental value as the curves remain linear. More factors must be considered for evaluating the compression behavior of the cakes of compressible soft particles.
Subjects
可壓縮
不可壓縮
軟粒子
壓縮模式
堆積床
濾餅局部性質
compressible
incompressible
compression model
particle bed
local cake properties
Type
thesis
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