Abstract

This study deals with the modelling and simulation of low density polyethylene (LDPE) production. LDPE is one of the most widely produced polymers which ap-pears in the form of simple goods in our everyday life (e.g. food and pharmaceutical packaging, carrier bags). It is produced in a complex industrial process which takes place under extreme operating conditions (at pressure of ca. 2000-3000 bar) and may lead to nonlinear dynamics due to highly exothermic addition polymerization reactions. In principle, the process is represented by a distributed system with an external coordinate (the reactor length > 1000m) and various internal coordinates (the chain length of the polymer molecules, short and long chain branching and the number of double bounds), which can have strong effect on product properties. In this con-tribution a detailed reference model is introduced and possible model simplifications are discussed systematically from an on-line optimization and control point of view.