Investigation of skin formation during filtration of micro crystalline cellulose

Artikel i vetenskaplig tidskrift, 2013

Separating solids from liquids through filtration is an important unit operation employed in a wide range of industrial sectors. It is vital that accurate and applicable models are employed when designing industrial sized filters. Comprehensive models are readily available for materials that form incompressible cakes, whereas those for compressible cakes are lacking. Materials that form compressible filter cakes may also form a dense initial cake close to the filter medium, i.e. a 'skin'. In this study the local filtration properties of a model material, TiO 2 , and micro-crystalline cellulose (MCC), are measured to investigate skin formation in a compressible filter cake. Indications of the formation of a skin in the filtration experiments using MCC could be observed; local pressure measurements were found to be useful in the investigation of its formation. Both the choice of the filter medium and the electrostatic interactions affected the skin formation. The tendency for skin to form was reduced at a lower pH, this lower pH corresponding to less charged particles and filter media.