Particle size improvement by a countercurrent tower crystallizer

Farmer, Robert W.; Beckman, James R.

doi:10.1002/aic.690320706

Cited by 4 publications

(1 citation statement)

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“…Application of staged crystallizers to solution crystallization has been rather limited in the literature since Beckman and Farmer conducted their first study more than two decades ago. , There were no accessories on the partition plates in their countercurrent crystallizer except a circular opening in the center which doubled as the passage for the stirrer shaft. Aqueous solutions of cation and anion were introduced to the top and bottom compartment respectively to produce sparingly soluble salts.…”

Section: Introductionmentioning

confidence: 99%

Residence Time Distribution of Liquid and Solid Phases in a Novel Staged Crystallizer

Yu¹,

Tan²

2009

Ind. Eng. Chem. Res.

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A novel vertically staged continuous crystallizer is proposed in this work. It consists of a series of compartments stacked one above another with partition plates in between. A stirrer shaft with multiple impellers provides agitation in each compartment. Solution to be crystallized enters the crystallizer from the top and flows downward through all stages. Crystal product and mother liquor are collected from the bottom. Openings in partition plates with accessories attached serve as passages for slurry flow, allowing for control over interstage mixing of liquid phase and residence time distribution (RTD) of crystals. The hydrodynamics of such a crystallizer is investigated in a two-stage experimental setup. Water, PVC particles, and glass beads are used to investigate the influences of design and operating factors on interstage mixing of liquid phase and RTDs of both liquid and solid phases. Results show that interstage mixing of liquid phase can be repressed successfully to ensure the establishment of supersaturation gradient across stages. RTD of solid phase can be manipulated by adjusting the feeding rate of liquid phase and opening size in the partition plate. Average residence time of solids deceases with increasing particle size, leading to classification of particles. A model is proposed for the RTD of solid phase which agrees with experimental data very well.

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Section: Introductionmentioning

confidence: 99%