Calibration of a polyethylene plant for grade change optimizations

Publication type: 
Conference paper
Author: 
Niklas Andersson, Per-Ola Larsson, Johan Ã…kesson, Staffan Haugwitz, Bernt Nilsson
Publication: 
21st European Symposium on Computer-Aided Process Engineering
Publisher: 
ESCAPE
Year: 
2011
Abstract: 
<p>A polyethylene plant model coded in Modelica and based on a nonlinear MPC model currently used at Borealis AB is considered for calibration. A case study of model calibration at steady-state for four different operating points are analysed, both when looking at one operating point separately, but also to calibrate several simultaneously. Both model parameters and reactor inputs are calibrated for true plant measurement data. To solve the parameter estimation problem, the JModelica.org platform is used, offering tools to express and solve calibration problems. Calibration was obtained with narrow confidence intervals and shows a potential to improve the model accuracy by changing the parameter values. The results will be used for dynamic optimisations of grade changes.</p>