Catalyst fragmentation during propylene polymerization: Part I. The effects of grain size and structure

Authors

  • Monica A. Ferrero,

    1. INTEC, (Universidad Nacional del Litoral—CONICET), Guemes 3450, (3000) Santa Fe, Argentina
    Search for more papers by this author
    • Research Assistant, INTEC, Consejo Nacional de Investigaciones (CONICET), Argentina.

  • Mario G. Chiovetta

    Corresponding author
    1. INTEC, (Universidad Nacional del Litoral—CONICET), Guemes 3450, (3000) Santa Fe, Argentina
    • INTEC, (Universidad Nacional del Litoral—CONICET), Guemes 3450, (3000) Santa Fe, Argentina
    Search for more papers by this author
    • Professor, INTEC, Universidad Nacional del Litoral, Santa Fe, Argentina: Researcher, Consejo Nacional de Investigaciones (CONICET), Argentina


Abstract

Fragmentation of support/catalyst particles during propylene polymerization in the gas phase is analyzed via a mathematical model including energy and mass transfer with chemical reaction processes. The rupture phenomenon is considered specifically by the model, and evaluated as it proceeds in time, Two different regions are recognized in the polymerizing particle at fragmentation time: an inner core resembling the original solid support/catalyst structure, and an external set of layers where most of the polymerization occurs. Model predictions concerning the effects of fragmentation on polymerization are discussed. The influence of different degrees of fragmentation on thermal runaways and monomer availability at active sites located inside the support/catalyst/polymer complex is shown. Monomer concentration profiles inside the growing particles are explained in terms of the combined fragmentation-polymerization interaction. Results show a strong influence of catalyst structure on critical phenomena during early polymerization stages, and suggest the possibility of controlling critical parameters via the definition of fragment structure at catalyst preparation time.

Ancillary