Modeling and analysis of a slurry reactor system for heterogeneous olefin polymerization: The effects of hydrogen concentration and initial catalyst size

Abstract

This article deals with the development of a model for the polymerization process using a Ziegler‐Natta catalyst in a slurry reactor system. Employed here is the hierarchical model describing the entire reactor system that is subcategoried by the gas bubble phase, the continuous gas phase, the liquid phase, the solid polymer particle, and the surface of catalyst where chemical reaction occurs. The concept of the multigrain model (MGM) is introduced to describe the growth of polymer particle from the original catalyst particle. We also adopt the concept of multiple active sites to elucidate the broad molecular weight distribution (MWD). The major concern here is the effects of the hydrogen concentration and the size of the initial catalyst on the performance of the polymerization reactor. It is demonstrated that the hydrogen gas can be used for the purpose of controlling not only the molecular weight but the molecular weight distribution (MWD) of the polymer. In addition, the relationship between the molecular weight and the concentration of hydrogen gas is investigated. The size of the initial catalyst is found to exercise a significant influence on the morphology of the resultant polymer particle. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2480–2493, 2001

Early Stages of Propylene Bulk Phase Polymerization with Supported Metallocene Catalysts

“…This situation is described by the multigrain model. [8][9][10][11][12][13] At this stage of polymerization about the highest overall activity is reached and the polymerization process should proceed at a relatively stable rate during the period of particle expansion.…”

Investigation of Alkoxysilanes in the Presence of Hydrogen with Ziegler-Natta Catalysts in Ethylene Polymerization

“…Then, the crystallinity was improved [28,30]. The MWD of polymer remained significantly unchanged with hydrogen concentration [31,32]. …”

Modeling and simulation of an industrial slurry-phase catalytic olefin polymerization reactor series

“…On the other hand, Zacca and Ray (1993) assumed that the flow behaviour in the loop reactor can be approximated by a series of tubular sections interconnected by perfectly mixed inlet and outlet zones. Ha et al (2001) investigated the operation of a semibatch slurry olefin polymerization reactor by employing a multiscale, multi-phase model in order to assess the effect of hydrogen concentration and catalyst initial size on the polymerization rate. Khare et al (2002) developed a generalized polymerization process simulator to describe the steady-state operation of a slurry-phase industrial plant.…”