Modeling mass transport of propylene polymerization on Ziegler–Natta catalyst

Abstract In the present article, a comprehensive mathematical model for single particle propylene polymerization mainly extended from polymeric multigrain model (PMGM) and multigrain model (MGM) has been developed to describe kinetic behavior, molecular weight distribution, monomer concentration, degree of polymerization and polydispersity index (PDI) for slurry-phase propylene polymerization using heterogeneous Ziegler–Natta catalysts. The modified model gives a more valid mathematical description by accounting for the monomer diffusion phenomena at two levels, namely, taking the effect of monomer diffusion at both the macro- and microparticle levels into account, and the latter is aside from the subject under consideration by PMGM. It has been observed that the present model can predict higher values of polydispersity index (PDI about 6–25) with obtaining some results which are more applicable to the conditions existing in most polymerizations of industrial interest such as the reasonable monomer concentration at the center of particles throughout polymerization process and the effect come nearer to the actual physical process of the initial radius of macro- and microparticles as well when using single-site, non-deactivating catalyst. Further, special attention is also paid in this article to discuss the computational rate, which is the most disadvantage of MGM. It has been shown that the significant computational time saving is also acquired by employing the novel solution methodology.

[1]  Argimiro Resende Secchi,et al.  Modeling and Simulation of Propylene Polymerization in Nonideal Loop Reactors , 2003 .

[2]  W. H. Ray,et al.  Polymerization of olefins through heterogeneous catalysis X: Modeling of particle growth and morphology , 1992 .

[3]  Daljit Singh,et al.  MOLECULAR WEIGHT DISTRIBUTION OF POLYETHYLENE PRODUCED BY ZIEGLER-NATTA CATALYSTS , 1971 .

[4]  R. Galván,et al.  Orthogonal collocation applied to analysis of heterogeneous Ziegler-Natta polymerization , 1986 .

[5]  W. Ray,et al.  Polymerization of olefins through heterogeneous catalysis. II. Kinetics of gas phase propylene polymerization with Ziegler–Natta catalysts , 1985 .

[6]  C. Kiparissides,et al.  Heat and mass transfer phenomena during the early growth of a catalyst particle in gas-phase olefin polymerization : the effect of prepolymerization temperature and time , 2001 .

[7]  P. McLellan,et al.  Effects of operating conditions on stability of gas‐phase polyethylene reactors , 1995 .

[8]  M. Boyce,et al.  Multiscale micromechanical modeling of polymer/clay nanocomposites and the effective clay particle , 2004 .

[9]  Alexander Penlidis,et al.  Mathematical Modeling of Multicomponent Chain-Growth Polymerizations in Batch, Semibatch, and Continuous Reactors: A Review , 1997 .

[10]  D. Estenoz,et al.  Olefin polymerization using supported metallocene catalysts: Process representation scheme and mathematical model , 2001 .

[11]  W. Ray,et al.  Polymerization of Olefins through Heterogeneous Catalysis. III. Polymer Particle Modelling with an Analysis of Intraparticle Heat and Mass Transfer Effects. , 1986 .

[12]  J. R. Street,et al.  Polymerization in expanding catalyst particles , 1971 .

[13]  M. Kakugo,et al.  Growth of polypropylene particles in heterogeneous Ziegler-Natta polymerization , 1989 .

[14]  Timothy F. L. McKenna,et al.  Single particle modelling for olefin polymerization on supported catalysts: A review and proposals for future developments , 2001 .

[15]  M. Ferrero,et al.  Catalyst fragmentation during propylene polymerization: Part I. The effects of grain size and structure , 1987 .

[16]  S. Gupta,et al.  SIMULATION OF PROPYLENE POLYMERIZATION: AN EFFICIENT ALGORITHM , 1992 .

[17]  Shiping Zhu,et al.  Effects of Diffusion‐Controlled Radical Reactions on RAFT Polymerization , 2003 .

[18]  V. W. Buls,et al.  A uniform site theory of ziegler catalysis , 1970 .

[19]  W. Harmon Ray,et al.  PREDICTION OF MOLECULAR WEIGHT DISTRIBUTIONS FOR HIGH-DENSITY POLYOLEFINS , 1980 .

[20]  K. Westerterp,et al.  The particle as microreactor: catalytic propylene polymerizations with supported metallocenes and Ziegler-Natta catalysts , 1999 .

[21]  Modelling of propylene polymerization in an isothermal slurry reactor , 1991 .

[22]  Hallvard F. Svendsen,et al.  Modeling of transfer phenomena on heterogeneous Ziegler catalysts. IV. Convection effects in gas phase processes , 2001 .

[23]  David W. Bacon,et al.  Modeling molecular weight development of gas‐phase α‐olefin copolymerization , 1995 .

[24]  T. McKenna,et al.  Modeling of transfer phenomena on heterogeneous Ziegler catalysts: Differences between theory and experiment in olefin polymerization (an introduction) , 1995 .

[25]  W. Harmon Ray,et al.  Nonlinear dynamics found in polymerization processes — a review , 2000 .

[26]  W. H. Ray,et al.  Polymerization of olefins through heterogeneous catalysis. VI. Effect of particle heat and mass transfer on polymerization behavior and polymer properties , 1987 .