Effects of Mixing Ratio of Binary Fine Particles on the Packing Density and Filtration Characteristics

Abstract

Binary fine particles were dispersed in glycerol aqueous solutions with different mixing ratios to study the effects of particle size distribution and fluid viscosity on the cake properties in dead-end filtration, such as average porosity, average specific filtration resistance and compressibility of cake. The average specific cake filtration resistance increases with increasing the fraction of small particles. However, the lowest cake porosity occurs under the volume fraction of large particles of 0.75. Comparing different methods for porosity estimations, model estimation is more accurate for those particles near pure composition, while simulation method is more suitable for moderate composition of particle mixtures. Furthermore, the cake porosity increases but the average specific cake filtration resistance decreases with increasing fluid viscosity. An 18 % porosity increase and a 30 % filtration resistance decrease are obtained when fluid viscosity increases from 1 to 10 × 10−3 Pa·s. The cake properties, such as the particle packing structure in the cake and the resulting filtration resistance, are affected not only by the particle size distribution but also by the fluid viscosity. The particle size distribution plays a much more important role on the cake compressibility than the fluid viscosity does.

Keywords

• particle size distribution
• microfiltration
• cake properties
• fluid viscosity
• packing porosity
• filtration