Reactor Modeling, Convergence Tips and Data-Fit Tool

This chapter provides a comprehensive exploration of kinetic reactor modeling in Aspen Plus/Polymers for polyolefin manufacturing, introducing three distinct reactor types: continuous stirred-tank reactors (RCSTR), plug-flow reactors (RPLUG), and batch/semi-batch reactors (RBATCH). Detailed configurations and specifications of these reactors are examined, alongside methodologies for representing nonideal reactor behavior. The chapter presents innovative strategies for optimizing computational efficiency, including accelerated solution techniques for conservation equations and phase-equilibrium calculations. It further highlights a robust data-fitting tool, enabling regression of critical simulation parameters such as reaction kinetics, heat-transfer coefficients, and property model inputs. Practical application is emphasized through hands-on workshops demonstrating kinetic parameter estimation using time-evolution concentration profiles and polymer attribute metrics like number-average and weight-average molecular weights. This focused discussion provides actionable insights into advanced reactor modeling and parameter optimization, enhancing predictive accuracy and process efficiency for polyolefin manufacturing systems. This is a preprint version of a chapter from our book-Integrated Process Modeling, Advanced Control and Data Analytics for Optimizing Polyolefin Manufacturing. Please cite the original work if referenced [12,15] 3.1 Kinetic or Rate-Based Reactors We introduce the three types of kinetic or rate-based reactor models available within Aspen Plus/Polymers for polyolefin manufacturing, including continuous stirred-tank reactor (RCSTR), plug-flow reactor (RPLUG), and batch or semi-batch reactor (RBATCH). We focus on configurations and specifications of the three kinetic reactors in Sections 3.2 to 3.4, and on the representation of nonideal reactors in Section 3.5. We present practical tips to speed up the solution of mass, energy and polymer attribute conservation equations and phase-equilibrium calculations in Sections 3.6 and 3.7. Section 3.8 discusses the data-fit tool for regressing all types of simulation parameters, such as reaction kinetics, heat-transfer coefficients, and any accessible model input parameters (including property model parameters). Sections 3.9 and 3.10 cover hands-on workshops applying the data fit for kinetic parameter estimation using time-evolution concentration profile and polymer attribute values (such as MWN and MWW). Section 3.11 presents the bibliography.