Using the Quasi-Steady-State\nApproximation to Reduce\nthe Computation Time of the Polymeric Flow Model for Olefin Homopolymerization

In this article we propose a novel way to solve the Polymer\nFlow\nModel (PFM) using the quasi steady-state approximation (QSSA). The\naccuracy of the QSSA model was quantified by comparing polymerization\nrates, particle growth factors, mass transfer efficiencies, and molecular\nweight distributions simulated at different Thiele modulus values\nwith the predictions from two different non steady-state (dynamic)\nsolutions of the PFM. The QSSA model predictions become increasingly\nmore accurate after the first few minutes of polymerization for catalysts\nwith low to medium Thiele moduli. Even though the proposed QSSA method\ndeviates more significantly from the PFM dynamic solution at high\nThiele modulus values, from a practical point of view this is of little\nrelevance since this condition corresponds to high levels of mass\ntransfer limitations that are avoided in industrial processes. Finally,\nthe computation time of the QSSA method is drastically faster than\nthose of dynamic models, making the proposed approach ideal for integration\nwith large-scale industrial models that must describe whole polymer\nparticle populations instead of single particles.