Effect of impeller design and power consumption on crystal size distribution

Crystallization processes in a 500 mL stirred tank crystallizer with computational fluid dynamics (CFD) and population balances toward estimating how crystal size distributions (CSDs) are influenced by flow inhomogeneities was explored. The flow pattern and CSD are presented here though extensive phase Doppler particle analyzer measurements and CFD predictions for three different impeller designs (disc turbine, pitched blade turbine, and Propeller) and each rotated at three different speeds (2.5, 5, and10 r/s). As crystallization processes in practice could involve break-up and aggregation of crystals, some selected break-up and aggregation kernels are incorporated. Extensive comparison of simulations with experimental data showed consistent trends in the proper quantitative range. An attempt has also been made to develop scaling laws: (a) mean particle size with average power consumption per unit mass and (b) particle-size distribution with the turbulent energy dissipation distribution. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3596–3613, 2014

[1]  Adel F. Sarofim,et al.  Models of secondary nucleation attributable to crystal‐crystallizer and crystal‐crystal collisions , 1974 .

[2]  Jerzy Bałdyga,et al.  Barium sulphate precipitation in a pipe — an experimental study and CFD modelling , 2001 .

[3]  R. Fox,et al.  Direct numerical simulation of gas–solid suspensions at moderate Reynolds number: Quantifying the coupling between hydrodynamic forces and particle velocity fluctuations , 2010 .

[4]  Zoltan K. Nagy,et al.  Detached eddy simulation on the turbulent flow in a stirred tank , 2012 .

[5]  Csaba Sinka,et al.  Modeling and measurement of granule attrition during pneumatic conveying in a laboratory scale system , 2008 .

[6]  J. Joshi,et al.  Critical impeller speed for solid suspension in mechanically agitated three-phase reactors. 1. Experimental part , 1991 .

[7]  Vivek V. Ranade,et al.  Gas–liquid flow generated by a Rushton turbine in stirred vessel: CARPT/CT measurements and CFD simulations , 2005 .

[8]  Zai-Sha Mao,et al.  Computational Fluid Dynamics Approach to the Effect of Mixing and Draft Tube on the Precipitation of Barium Sulfate in a Continuous Stirred Tank , 2006 .

[9]  Vivek V. Ranade,et al.  FLOW GENERATED BY PITCHED BLADE TURBINES I: MEASUREMENTS USING LASER DOPPLER ANEMOMETER , 1989 .

[10]  Peter J.T. Verheijen,et al.  Modeling of industrial crystallizers for control and design purposes , 2000 .

[11]  Chinmay V. Rane,et al.  CFD simulation of stirred tanks: Comparison of turbulence models. Part I: Radial flow impellers , 2011 .

[12]  Vivek V. Ranade,et al.  Flow generated by a disc turbine. II: Mathematical modelling and comparison with experimental data , 1990 .

[13]  Vivek V. Ranade,et al.  Comparison of axial flow impellers using a laser doppler anemometer , 1992 .

[14]  Wei Zhou,et al.  Computational Fluid Dynamics Modeling of the Precipitation Process in a Semibatch Crystallizer , 2001 .

[15]  Doraiswami Ramkrishna,et al.  Population balance modeling for bubble columns operating in the homogeneous regime , 2007 .

[16]  Zdzisław Jaworski,et al.  THE EFFECT OF SIZE, LOCATION AND PUMPING DIRECTION OF PITCHED BLADE TURBINE IMPELLERS ON FLOW PATTERNS: LDA MEASUREMENTS AND CFD PREDICTIONS , 2001 .

[17]  Alberto Brucato,et al.  Large-eddy simulation of turbulent flow in an unbaffled stirred tank driven by a Rushton turbine , 2005 .

[18]  Piotr Synowiec,et al.  Suspension flow in crystallizers with and without hydraulic classification , 2010 .

[19]  Vivek V. Ranade,et al.  CFD simulation of stirred tanks: Comparison of turbulence models (Part II: Axial flow impellers, multiple impellers and multiphase dispersions) , 2011 .

[20]  Catherine Xuereb,et al.  3-D hydrodynamics in a tank stirred by a double-propeller system and filled with a liquid having evolving rheological properties , 1996 .

[21]  Marjatta Louhi-Kultanen,et al.  Application of CFD simulation to suspension crystallization—factors affecting size-dependent classification , 2001 .

[22]  Jyeshtharaj B. Joshi,et al.  Effect of impeller design on the flow pattern and mixing in stirred tanks , 2006 .

[23]  Adrian E. Flood,et al.  NUMERICAL SIMULATION AND ANALYSIS OF FLOW IN A DTB CRYSTALLIZER , 2008 .

[24]  Vivek V. Ranade,et al.  Flow generated by a disc turbine. I: Experimental , 1990 .

[25]  J. Joshi,et al.  CFD simulations of gas-liquid-solid stirred reactor: prediction of critical impeller speed for solid suspension , 2007 .

[26]  J. Derksen.  Numerical Simulation of Solids Suspension in a Stirred Tank , 2003 .

[27]  H. Muhr,et al.  CFD simulation of precipitation in the sliding-surface mixing device , 2001 .

[28]  Vivek V. Ranade,et al.  FLOW GENERATED BY PITCHED BLADE TURBINES II: SIMULATION USING κ-ε MODEL , 1989 .

[29]  Ping Li,et al.  Optimization Design for DTB Industrial Crystallizer of Potassium Chloride , 2010 .

[30]  Bhaskar D. Kulkarni,et al.  Identification and characterization of flow structures in chemical process equipment using multiresolution techniques , 2008 .

[31]  M. Vakili,et al.  CFD analysis of turbulence in a baffled stirred tank, a three-compartment model , 2009 .

[32]  Z. Sha,et al.  Mixing and crystallization in suspensions , 2000 .

[33]  D. Thévenin,et al.  Numerical and analytical investigation of barium sulphate crystallization , 2006 .

[34]  Alvin W. Nienow,et al.  CFD modelling of continuous precipitation of barium sulphate in a stirred tank , 2003 .

[35]  Adel F. Sarofim,et al.  Mechanisms of secondary nucleation in agitated crystallizers , 1974 .

[36]  Vivek V. Ranade,et al.  Computational fluid dynamics for designing process equipment: Expectations, current status, and path forward , 2003 .

[37]  H. Svendsen,et al.  Theoretical model for drop and bubble breakup in turbulent dispersions , 1996 .

[38]  Jyeshtharaj B. Joshi,et al.  Assessment of standard k–ε, RSM and LES turbulence models in a baffled stirred vessel agitated by various impeller designs , 2008 .

[39]  Gabriel Wittum,et al.  Simulation of crystal growth and attrition in a stirred tank , 2006 .

[40]  Mandar Tabib,et al.  Analysis of dominant flow structures and their flow dynamics in chemical process equipment using snapshot proper orthogonal decomposition technique , 2008 .

[41]  Suzanne M. Kresta,et al.  Active volume of mean circulation for stirred tanks agitated with axial impellers , 2000 .

[42]  Bhaskar D. Kulkarni,et al.  Application of multiresolution analysis for simultaneous measurement of gas and liquid velocities and fractional gas hold-up in bubble column using LDA , 2001 .

[43]  A. Bakker,et al.  Modelling of Turbulence in Stirred Vessels Using Large Eddy Simulation , 2004 .

[44]  S. Katz,et al.  Some problems in particle technology: A statistical mechanical formulation , 1964 .

[45]  D. Pinelli,et al.  Dispersion coefficients and settling velocities of solids in slurry vessels stirred with different types of multiple impellers , 2004 .

[46]  Allan S. Myerson,et al.  CFD simulations for analysis and scale‐up of anti‐solvent crystallization , 2006 .