The strongly exothermic polymerization process is a nonlinear process which generally have multi-stable phenomenon. Different steady state has different local stability. The Innovene process which uses gas-phase horizontal stirred bed reactor

is one of the most advanced technology for propylene polymerization. A reactor model using Polymer Plus was built. This model is more consistent with actual cases and suitable for steady-state multiplicity analysis. The reaction parameters were obtained by fitting the GPC data of products. The steady-state multiplicity characteristics by the sensitivity analysis of steady-state model were also analyzed. An inferential analysis method for judging the stability of steady-state solutions was proposed

and the intrinsically safe operating range for each reactor area was identified finally. This is an important work for the stable operation and the development of new grades of polypropylene.