Biomassapohjaisten lietteiden suodattuvuuden mallinnus

The aim of this thesis was to investigate factors, which has the most effect on slurry filterability, and to create a model predicting filterability from collective slurry charasteristics with different slurries and process conditions. The work is focused on cake filtration, which is a major solid-liquid separation method in wide range of industries. The work consists literature review, experimental part and modeling part. In the experimental part both filterability and the material properties of different slurries were investigated. Filtration tests series consisted comparing filterability with eight different biomass based slurried in the same process conditions, but also a wider test series which investigated the effect of temperature and pressure was committed with three slurries. Also individual tests considering changes in pH, effect of selected filter cloth and effect of slow pressure increase was investigated. The slurry properties were either measured in laboratory or collected from literature. The measured slurry properties were selected based on literature review, being particle size, shape and density, liquid density and viscosity, zeta-potential and conductivity. The results of the work are, that especially slurry pH and particle interactions have a remarkable role on filterability. Instead, particle size distribution did not have a clear effect on filterability with slurries used in this work, even though particle size is widely recognized to be a decisive parameter affecting filterability in literature. The created model give remarkably better estimation of filterability compared to the convinental models, but because of the complication of filtration, a perfect model could not be created. More investigation is needed esipecially considering how different interparticle forces effect on filterability