Chemical Engineering Science 56 (2001) 3931–3949 www.elsevier.com/locate/ces Single particle modelling for olen polymerization on supported catalysts: A review and proposals for future developments Timothy F. McKenna a ; * ,Jo˜ ao B. P. Soares b a CNRS-LCPP=ESCPE-Lyon, BP 2077, 43 Blvd du 11 Novembre 1918, 69616 Villeurbanne Cedex, France b Department of Chemical Engineering, Institute for Polymer Research, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 Abstract In the present article, we review the state-of-the-art models for single particle olen polymerization models. Special attention is paid to particle growth, polymerization rates, concentration and temperature radial proles, polymer microstructure, and particle morphology. It is proposed that these models can be conveniently classied as polymer property and particle morphology models, according to their most important predictive abilities, even though particle morphology characteristics will inuence polymer properties and vice versa. Currently, there is no single model that incorporates all of these modelling aspects into a unied formulation. A great deal of progress has been made toward understanding the relationship between the important phenomena involved in modelling single particle growth. It seems that the basic understanding on modelling polymer properties is quite substantial, but there is still signicant contributions to be made when modelling the morphology evolution of these complex polymer particles. Some of these areas are discussed and suggestions for future development are made. ? 2001 Elsevier Science Ltd. All rights reserved. Keywords: Polymerization; Olen polymerization; Mass transfer; Heat transfer; Polyolens; Diusion 1. Introduction Based on production data for 1999 and 2000, 85–95 million tons of polyolens (essentially ho- mopolymers and copolymers of propylene and ethy- lene) are produced around the world. The worldwide polypropylene capacity is approximately 34 million tons, all of which is made with supported catalysts. Sixty percent of the remaining polyethylene is made on supported catalysts, bringing the current market for polyolens produced on supported catalysts to a to- tal of 65–70 millions tons per year (Razavi, 1999; Potter & Tattum, 1998, http:== www.spmp.proplast.org, http:== www.apme.org= europe). This already impressive market is still in full growth, with Foxely (1998) pre- dicting growth rates of about 30% for PP and about 18% for PE products for the period from 2000 to 2005. ∗ Corresponding author. Tel.: +33-4-724-31775; fax: +33-4-724- 31768. E-mail addresses: mckenna@cpe.fr (T. F. McKenna), jsoares@uwaterloo.ca (J. B. P. Soares). Most industrial catalysts for olen polymerization are heterogeneous Ziegler–Natta or chromium oxide systems (approximately 43% and 20% of all polyethylene prod- ucts, respectively, with almost all polypropylene resins produced with Ziegler–Natta catalysts). Metallocenes are very versatile catalysts for olen polymerization but still remain relatively small in terms of market share. For instance, Tattum and Potter (1998) project that by 2002, only 4% of all polypropylene will be made with metallocenes, while Foxely (1998) projects a 2.3% contribution for polyethylenes in the same time frame. However, it is expected that the contribution from met- allocene catalysts should increase signicantly over the next decade. Soluble Ziegler–Natta catalysts have only found industrial applications for the production of ethylene–propylene–diene rubbers, mainly because of insucient catalytic stability and stereochemical control. Ziegler–Natta catalysts are formed by a transition metal salt of elements of groups IV–VIII and a metal alkyl of a element of groups I–III (known as cocatalyst or ac- tivator). Phillips catalysts are typically based on chro- mium oxides. Metallocene catalysts are organometallic 0009-2509/01/$ - see front matter ? 2001 Elsevier Science Ltd. All rights reserved. PII:S0009-2509(01)00069-0