New transformation proposed for improving CFD simulation of free radical polymerization reactions in microreactors

Abstract A new yet simple transformation is proposed to significantly improve the accuracy of computational fluid dynamics (CFD) modeling and simulations of free radical polymerization (FRP) reactions carried out especially in flow microreactors. The new transformation makes the kinetic rate coefficients dimensionless in terms of concentration. To that extent, the chemical data (chemical species concentration and kinetic rate coefficients values) can be fed in original molar form instead of usual mass form to CFD software package while simulating chemical species as passive scalars. The normalization of various variables (passive scalars) helps in reducing the numerical stiffness as well as numerical errors during simulations. Another advantage of this new transformation is that the expression for transformed reaction rate equations remains unchanged thus enabling an easy coding and debugging process. The new transformation was first validated through numerical simulation against theoretical analytical solution of FRP for homogeneous batch reactor. It was then validated through CFD simulation against published experimental data for FRP in coiled tube microreactor under steady-state flow condition. It has also been demonstrated that in CFD simulations of FRP in flow microreactors, significant error arises for the prediction of number-average chain length (and thus $${\text{MW}}_{n}$$MWn, number-average molecular weight) from the use of chemical data in mass form instead of original molar form. This new transformation is thus found to be more suitable for CFD simulations in flow reactors compared to previous Zhu’s transformation.

[1]  C. Kiparissides,et al.  Development of a unified mathematical framework for modelling molecular and structural changes in free-radical homopolymerization reactions , 1992 .

[2]  Yannick Hoarau,et al.  Numerical modeling of polystyrene synthesis in coiled flow inverter , 2011 .

[3]  Enrique Luis Lima,et al.  Free‐radical solution polymerization of styrene in a tubular reactor—effects of recycling , 2003 .

[4]  Chi-Chin Chen.  CONTINUOUS PRODUCTION OF SOLID POLYSTYRENE IN BACK-MIXED AND LINEAR-FLOW REACTORS , 2000 .

[5]  David S. Soong,et al.  Free-radical polymerization of methyl methacrylate in tubular reactors , 1985 .

[6]  D. Poulikakos,et al.  Laminar mixing, heat transfer and pressure drop in tree-like microchannel nets and their application for thermal management in polymer electrolyte fuel cells , 2004 .

[7]  Costas Kiparissides,et al.  Development of a General Mathematical Framework for Modeling Diffusion-Controlled Free-Radical Polymerization Reactions , 1992 .

[8]  Dimos Poulikakos,et al.  Effects of microreactor wall heat conduction on the reforming process of methane , 2005 .

[9]  D. Soong,et al.  Major factors contributing to the nonlinear kinetics of free-radical polymerization , 1985 .

[10]  V. Hessel,et al.  Numerical simulation of polymerization in interdigital multilamination micromixers. , 2005, Lab on a chip.

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

[12]  Shiping Zhu,et al.  Modeling of molecular weight development in atom transfer radical polymerization , 1999 .

[13]  E. F. Costa,et al.  On the numerical solution and optimization of styrene polymerization in tubular reactors , 2003, Comput. Chem. Eng..

[14]  Costas Kiparissides,et al.  Toward the Development of a General Framework for Modeling Molecular Weight and Compositional Changes in Free-Radical Copolymerization Reactions , 1992 .

[15]  Y. Hoarau,et al.  Analytical Solution of Free Radical Polymerization: Derivation and Validation , 2014 .

[16]  C. C. Chen,et al.  A Continuous Bulk Polymerization Process for Crystal Polystyrene , 1994 .

[17]  Christophe A. Serra,et al.  Free radical polymerization in multilaminated microreactors: 2D and 3D multiphysics CFD modeling , 2007 .

[18]  Costas Kiparissides,et al.  Development of a Comprehensive Model for Diffusion-Controlled Free-Radical Copolymerization Reactions , 2002 .

[19]  Robin H. Liu,et al.  Bubble-induced acoustic micromixing. , 2002, Lab on a chip.

[20]  P. Woias,et al.  Theoretical and Experimental Investigations of Convective Micromixers and Microreactors for Chemical Reactions , 2010 .

[21]  Y. Hoarau,et al.  Analytical Solution of Free Radical Polymerization: Applications- Implementing Gel Effect Using AK Model , 2014 .