Modeling the Dynamics of the Xylene Soluble Fraction (XS) in a Bulk Propylene Polymerization Process (original) (raw)

Mathematical Modelling and Simulation of an Industrial Propylene Polymerization Batch Reactor

The aim of this research is to develop a mathematical model for the propylene polymerization batch reactor for a local petrochemical company. The kinetics of polymerization is based on a single type of active sites on Ziegler–Natta catalyst. The model is composed of a number of algebraic and stiff ordinary differential equations which are solved simultaneously using MATLAB script language. The developed model was used to predict the properties of end-product, which include weight and number average molecular weight, polydispersity index (PDI) and melt flow index (MFI). The simulated batch runs were validated against real batch runs for the values of melt flow index. An average absolute error of 10.8 % was achieved.

Control of industrial gas phase propylene polymerization in fluidized bed reactors

Journal of Process Control, 2012

The control of a gas phase propylene polymerization model in a fluidized bed reactor was studied, where the rigorous two phase dynamic model takes into account the polymerization reactions occurring in the bubble and emulsion phases. Due to the nonlinearity of the process, the employment of an advanced control scheme for efficient regulation of the process variables is justified. In this case, the Adaptive Predictive Model-Based Control (APMBC) strategy (an integration of the Recursive Least Squares algorithm, RLS and the Generalized Predictive Control algorithm, GPC) was employed to control the polypropylene production rate and emulsion phase temperature by manipulating the catalyst feed rate and reactor cooling water flow, respectively. Closed loop simulations revealed the superiority of the APMBC in setpoint tracking as compared to the conventional PI controllers tuned using the Internal Model Control (IMC) method and the standard Ziegler-Nichols (Z-N) method. Moreover, the APMBC was able to efficiently arrest the effects of superficial gas velocity, hydrogen concentration and monomer concentration on the process variables, thus exhibiting excellent regulatory control properties.