Polymerization of propylene in a minireactor: Effect of polymerization conditions on particle morphology

Document Type : Original research

Authors

Iran Polymer and Petrochemical Institute, P.O.Box 14185/458, Tehran, Iran

Abstract

Gas phase polymerization of propylene was carried out in a semi-batch minireactor using a commercially supported Ziegler–Natta (ZN) catalyst. The influence of variables including monomer partial pressure, external electron donor, reaction temperature and time on the particle morphology and size distribution was investigated. Generally, more uniform fragmentation and particle densities were obtained at lower reaction rates. Monomer partial pressure showed a significant role of particle size and its distribution, the higher the monomer partial pressure, the broader particle size distribution was obtained. Polymerization pressure had a significant role on the morphology of particles. Wider cracks and more porosity were resulted from the polymerizations at higher pressures. Furthermore, a broader particle size distribution was obtained from the polymerization at higher pressures. The particle size analysis revealed the monomer partial pressure as the most effective parameter on the distribution of particles. The SEM images showed that three different steps could be distinguished in the development of particle morphology within the particle, showing the initiation and development of cracks and appearance of fragments inside the particle.

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Main Subjects


  1. Weickert G, Meier GB, Pater, JT M, Westerterp KR (1999) The particle as microreactor: Catalytic propylene polymerizations with supported metallocenes and Ziegler–Natta catalysts. Chem Eng Sci 54: 3291-3296
  2. Severn JR, Chadwick JC Eds. (2008) Tailor-made polymers: via immobilization of alpha-olefin polymerization catalysts. John Wiley & Sons, GMBH, ch. 3, 79-81
  3. Pasquini N, Antonio A (2005) Polypropylene handbook. Hanser publisher, Munich, Ch.2, 75-82
  4. Martin C, Mc Kenna TF (2002) Particle morphology and transport phenomena in olefin poly-merisation. Chem Eng J 87: 89-99
  5. Cecchin G, Marchetti E, Baruzzi G (2001) On the mechanism of polypropene growth over MgCl2/TiCl4 catalyst systems. Macromol Chem Phys 202:1987-1994
  6. Grof Z, Kosek J, Marek M (2005) Modeling of morphogenesis of growing polyolefin particles. AIChE J 51: 2048-2067
  7. Zheng X, Pimplapure MS, Weickert G, Loos J (2006) Influence of porosity on the fragmentation of Ziegler-Natta catalyst in the early stages of propylene polymerization. E-Polymers 6: 356-365
  8. Ferrero MA, Chiovetta MG (1991) Effects of catalyst fragmentation during propylene polymerization. IV: Comparison between gas phase and bulk polymerization processes. Polym Eng Sci 31: 904-911
  9. Pater J, Weickert G, Van Swaaij WP (2003) Polymerization of liquid propylene with a fourth generation Ziegler–Natta catalyst: Influence of temperature, hydrogen, monomer concentration, and prepolymerization method on powder morphology. J Appl Polym Sci 87: 1421-1435
  10. Horackova B, Grof Z, Kosek J (2007) Dynamics of fragmentation of catalyst carriers in catalytic polymerization of olefins. Chem Eng Sci 62: 5264-5270
  11. Kittilsen P, Svendsen HF, McKenna TF (2003) Viscoelastic model for particle fragmentation in olefin polymerization. AIChE J 49: 1495-1507
  12. Kittilsen P, Mc Kenna TF, Svendsen H, Jakobsen HA, Fredriksen SB (2001) The interaction between mass transfer effects and morphology in heterogeneous olefin polymerization. Chem Eng Sci 56: 4015-4028
  13. Najafi M, Parvazinia M, Ghoreishy MHR, Kiparissides C (2014) Development of a 2D single particle model to analyze the effect of initial particle shape and breakage in olefin polymerization. Macromol React Eng 8: 29-45
  14. Noristi L, Marchetti E, Baruzzi G, Sgarzi P (1994) Investigation of the particle growth mechanism in propylene polymerization with MgCl2-supported Ziegler–Natta catalysts. J Polym Sci 32: 3047-3059
  15. Zheng X, Loos J (2006) Morphology evolution in the early stages of olefin polymerization. Macromol Symp 236: 249-258
  16. Pater JT, Weickert G, Loos J, van Swaaij WP (2001) High precision prepolymerization of propylene at extremely low reaction rates—Kinetics and morphology. Chem Eng Sci 56: 4107-4120
  17. Taniike T, Funako T, Terano M (2014) Multilateral characterization for industrial Ziegler–Natta catalysts toward elucidation of structure–performance relationship. J Cat 311: 33-40
  18. McKenna TF, Di Martino A, Weickert G, Soares JB (2010) Particle growth during the polymerisation of olefins on supported catalysts, 1–nascent polymer structures. Macromol React Eng 4: 40-64
  19. Eberstein C, Garmatter B, Reichert KH, Sylvester G (1996) Gas phasen polymerisation von Butadien. Chemie Ingenieur Technik 68: 820-823
  20. Oleshko VP, Crozier PA, Cantrell RD, Westwood AD (2001) In-situ and ex-situ microscopic study of gas phase propylene polymerization over a high activity TiCl4-MgCl2 heterogeneous Ziegler-Natta catalyst. Macromol Rapid commun 22: 34-40
  21. Pater J, WeickertG, vanSwaaij WP (2003) Optical and infrared imaging of growing polyolefin particles. AIChE J 49: 450-464
  22. Abboud M, Kallio K, Reichert KH (2004) Video microscopy for fast screening of polymerization catalysts. Chem Eng Tech 27: 694-698
  23. Bneke Jnsm (2014) Microreactors: A new concept for chemical synthesis and technological feasibility. Mat Sci Eng 39: 89-101
  24. Mc Kenna TF, Tioni E, Ranieri MM, Alizadeh A, Boisson C, Monteil V (2013) Catalytic olefin polymerisation at short times: Studies using specially adapted reactors. Can J Chem Eng 91: 669-686
  25. Silva FM, Broyer JP, Novat C, Lima EL, Pinto JC, McKenna TF (2005) Investigation of catalyst fragmentation in gas-phase olefin polymerisation: A novel short stop reactor. Macromol Rapid Commun 26: 1846-1853
  26. Taniike T, Thang VQ, Binh NT, Hiraoka Y, Uozumi T, Terano M. (2011) Initial particle morphology development in Ziegler-Natta propylene polymerization tracked with stopped-flow technique. Macromol Chem Phys 212: 723-729
  27. Tioni E, Spitz R, Broyer JP, Monteil V, Mc Kenna TF (2012) Packed-bed reactor for short time gas phase olefin polymerization: Heat transfer study and reactor optimization. AIChE J 58: 256-267
  28. Browning B, Sheibat-Othman N, Pitault I, McKenna TF (2014) A 2-D observer to estimate the reaction rate in a stopped flow fixed bed reactor for gas phase olefin polymerization. AIChE J 60: 3511-3523
  29. Cancelas AJ, Monteil V, Mc Kenna TF (2017) Impact of catalyst injection conditions on the gas phase polymerization of propylene. React Chem Eng 2: 75-87
  30. Di Martino A, Broyer JP, Spitz R, Weickert G, McKenna TF (2005) A rapid quenched-flow device for the characterisation of the nascent polymerisation of ethylene under industrial conditions. Macromol Rapid Commun 26:215-220
  31. Di Martino A, Weicker G, McKenna TF (2007) Contributions to the experimental investigation of the nascent polymerisation of ethylene on supported catalysts. Macromol React Eng 1:165-184
  32. Di Martino A, Weickert G, McKenna TF (2007). Contributions to the experimental investigation of the nascent polymerisation of ethylene on supported catalysts. Macromol React Eng 1: 229-242
  33. Kanellopoulos V, Dompazis, G, Gustafsson B, Kiparissides C (2004) Comprehensive analysis of single-particle growth in heterogeneous olefin polymerization: The random-pore polymeric flow model. Ind Eng Chem Res 43: 5166-5180
  34. Dompazis G, Kanellopoulos V, Kiparissides C (2005) A multi scale modeling approach for the prediction of molecular and morphological properties in multi site catalyst, olefin polymerization reactors. Macromol Mat Eng 290: 525-536
  35. Di Martino A, Weickert G, Sidoroff F, McKenna TF (2007) Modelling induced tension in a growing catalyst/polyolefin particle: A multi scale approach for simplified morphology modelling. Macromol React Eng 1: 338-352
  36. Xalter R, Mülhaupt R (2010) Online monitoring of polyolefin particle growth in catalytic olefin slurry polymerization by means of lasentec focused beam reflectance measurement (FBRM) and video microscopy (PVM) Probes. Macromol React Eng 4: 25-39