Dynamic Modeling and Analysis of Process Constraints for Improvement for an Industrial Unipol® Polypropylene Fluidized Bed Reactor

Many researchers report optimizations of chemical processes based on steady-state analysis. However, neglecting the time factor may lead sometimes to more waste generation and/or hazardous safety consequences. In this regard, we recently detailed a comprehensive modeling of a fluidized bed reactor (FBR) for Unipol® polypropylene process using the sequential modular simulation approach while incorporating the hydrodynamic correlations. Furthermore, a steady-state analysis and optimization technique was used to increase the plant profitability. The current manuscript presents dynamic modeling to identify process constraints that obstruct the process improvement recommended by the previous study. The current dynamic model was validated using industrial operational scenarios. The dynamic model was then utilized to explore the response of the FBR control system protection layer to unplanned operational scenarios, its ability to avoid waste generation, and achieve process safety. As such, an automated HAZOP study based on layer of protection analysis concept was applied for this purpose. As a result, to apply the recommended scheme by the steady-state study while ensuring safety and cleaner production in the process, it is necessary to revamp the existing FBR cooling system. The extra cost for revamping the cycle gas cooler is trivial compared to the potential increase in the process safety besides the plant productivity.