CFD analysis of mixing in thermal polymerization of styrene

Abstract Thermal polymerization of styrene in a lab-scale CSTR equipped with a pitched blade turbine impeller was simulated using a computational fluid dynamics (CFD) software package. The rotation of the reactor impeller was modeled using the multiple reference frames (MRF) technique. The path lines of the particles, released at the reactor inlet, were also generated to analyze the reaction progress throughout the reactor vessel. The effects of the impeller speed, the input–output stream locations and the residence time were investigated. The simulation showed the formation of a well-mixed region around the impeller and stagnant or slow moving fluids elsewhere in the reactor due to high viscosity of the polymer mass. The monomer conversion computed using the CFD model was in good agreement with that obtained from the CSTR model at low residence time. The input–output locations have a significant impact on the monomer conversion and the system homogeneity in the CSTR.

[1]  Elizabeth M. Marshall,et al.  Modeling LDPE Tubular and Autoclave Reactors , 2001 .

[2]  F. Ein-Mozaffari,et al.  Using dynamic tests to study the continuous mixing of xanthan gum solutions , 2008 .

[3]  F. Mayo,et al.  The dimerization of styrene , 1968 .

[4]  Mf Maartje Kemmere,et al.  Emulsification in batch-emulsion polymerization of styrene and vinyl acetate : a reaction calorimetric study , 2001 .

[5]  Rodney O. Fox,et al.  PDF modeling of turbulent‐mixing effects on initiator efficiency in a tubular LDPE reactor , 1996 .

[6]  Guray Tosun.  A mathematical model of mixing and polymerization in a semibatch stirred‐tank reactor , 1992 .

[7]  Sandro Macchietto,et al.  A general methodology for hybrid multizonal/CFD models: Part II. Automatic zoning , 2004, Comput. Chem. Eng..

[8]  Heidari Javad,et al.  Effects of the Temperature and Mixing Rate on Foaming in a Polymerization Reaction To Produce Fatty Polyamides in the Presence of Catalyst , 2004 .

[9]  Farhad Ein-Mozaffari,et al.  Using ultrasonic Doppler velocimetry and CFD modeling to investigate the mixing of non-Newtonian fluids possessing yield stress , 2009 .

[10]  E. L. Paul,et al.  Handbook of Industrial Mixing , 2003 .

[11]  A. Hui,et al.  Thermal polymerization of styrene at high conversions and temperatures. An experimental study , 1972 .

[12]  W. Harmon Ray,et al.  Simulations of a LDPE reactor using computational fluid dynamics , 1997 .

[13]  P. Bartlett,et al.  The Thermal Reaction of Styrene with Ethyl Thioglycolate; Evidence for the Termolecular Thermal Initiation of Styrene Polymerization , 1959 .

[14]  M. Alpbaz,et al.  The effect of operational conditions on the performance of batch polymerization reactor control , 2002 .

[15]  Dong Min Kim,et al.  Solution viscosity of polystyrene at conditions applicable to commercial manufacturing processes , 1992 .

[16]  Hans-Ulrich Moritz,et al.  Increase in viscosity and its influence on polymerization processes , 1989 .

[17]  Alexander Penlidis,et al.  Simulation of Free Radical Bulk/Solution Homopolymerization Using Mono- and Bi-functional Initiators , 2000 .

[18]  Moustafa A. Soliman,et al.  Simulation of bulk free radical polymerization of styrene in tubular reactors , 1994 .

[19]  Sandro Macchietto,et al.  A general methodology for hybrid multizonal/CFD models: Part I. Theoretical framework , 2004, Comput. Chem. Eng..

[20]  A. Hamielec,et al.  Bulk and suspension polymerization of styrene in the presence of n‐pentane. An evaluation of monofunctional and bifunctional initiation , 1993 .

[21]  W. Harmon Ray,et al.  Modeling of imperfect mixing and its effects on polymer properties , 1997 .

[22]  Alexander Penlidis,et al.  A Comprehensive Simulator/Database Package for Reviewing Free-Radical Homopolymerizations , 1996 .

[23]  W. Harmon Ray,et al.  Effects of imperfect mixing on low‐density polyethylene reactor dynamics , 1998 .

[24]  A. Gosman,et al.  PREDICTION OF IMPELLER- INDUCED FLOW IN MIXING VESSELS USING MULTIPLE FRAMES OF REFERENCE , 1994 .

[25]  R. Laurence,et al.  The mixing effect on the free radical MMA solution polymerization , 1998 .

[26]  Rodney O. Fox,et al.  CFD analysis of micromixing effects on polymerization in tubular low-density polyethylene reactors , 1999 .