Steady-state behavior of slurry and bulk propylene polymerization

This paper analyzes the steady-state behavior of two typical processes to produce poly(propylene): the single-reactor, bulk. polymerization process and the slurry polymerization process in-a train- of continuous stirred tank reactors. The investigation is performed using a commercial process simulator-SIMULPOL 3.0(R) and aims at elucidating the general behavior of both processes when subject to perturbations of the input operation variables. Attention is given to the effect of the perturbations upon the polymer properties and to identification of process bottlenecks. Regarding the bulk polymerization process, unstable plant behavior was detected in the absence of a control policy. it was found that multiple steady-states are possible for this process as a consequence of the recycling of material. As a matter of fact, the reactor recycle flow rate was found to be a fundamental parameter for the bulk process. Unstable behavior can be eliminated with the implementation of classical control strategies.