engleski

Influence of impeller diameter on crystal growth kinetics of borax in mixed dual impeller batch cooling crystallizer

This work focuses on an analysis of an influence of impeller diameter on crystal growth kinetics of borax decahydrate in a batch cooling crystallizer of non-standard aspect ratio. Dual impeller configuration consisted of a pitched blade turbine (PBT) which was mounted below a straight blade turbine (SBT) on a single shaft. Three different impeller to tank diameter ratios in range from 0.27 to 0.46 were investigated. In all experiments, mixing was conducted at just suspended impeller speed. In order to examine hydrodynamic conditions, mixing time measurements were conducted. Also, fluid flow pattern and velocity distribution were evaluated by computational fluid dynamics. Results showed that the smallest but also, more regularly shaped crystals were produced in a system with standard diameter impellers, D/dT=0.33. Product yield was also highest in that case, as was the value of power consumption.

impeller diameter ; crystal growth kinetics ; mixed dual-impeller configuration ; CFD ; borax

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