Local filtration properties of microcrystalline cellulose

Paper in proceeding, 2015

One of the main challenges with obtaining energy-efficient solid-liquid separation in biorefineries is the formation of compressible filter cakes. In this study the effect of particle surface structure as well as particle surface charge on the local filtration behaviour of microcrystalline cellulose was investigated. The filtration kinetics was found to be affected by the particle surface structure as a rough particle surface increases the specific surface area subjected to drag forces. Similarly, it was found that the filtration kinetics was improved by a low particle surface charge as attractive particle interactions between particles/particle fragments results in a smaller specific surface area subjected to drag. However, filtration of microcrystalline cellulose may result in a rate limiting “skin layer” close to the filter media during conditions were the particle surface is charged and the attractive forces between particles as well as steric hindrance are insufficient to prevent a local collapse of the filter cake. This “skin layer” has a large influence on the required filtration time and/or filter area of the separation, and may not be detected without the use of local filtration properties.