Model-Based Optimization of Economical Grade Changes for the Borealis Borstar Polyethylene Plant
Författare
Summary, in English
Economical grade changes are considered for a Borealis Borstar polyethylene plant model, incorporating two slurry-phase reactors, one gas-phase reactor and a recycle area with three distillation columns. The model is constructed in the Modelica language and the JModelica.org platform is used for opti- mization. The cost function expresses the economical profit during a grade change and is formulated using on-grade intervals for seven polymer quality variables such as melt index, density and reactor split factors. Additionally, incentives to produce polymer with quality variables on grade target values, not only inside grade intervals, are added. Twelve inflows and three purge flows are used at optimization. Two grade changes are thoroughly reviewed, showing the effect of using a cost function that regards plant economy. Re- sulting trajectories can be divided into three phases with distinguishing fea- tures, and the synchronization of inflows and usage of recycle area off-gas flows are important in the grade changes.
Publiceringsår
2012
Språk
Engelska
Sidor
153-166
Publikation/Tidskrift/Serie
Computers & Chemical Engineering
Volym
46
Länkar
Dokumenttyp
Artikel i tidskrift
Förlag
Elsevier
Ämne
- Control Engineering
- Chemical Engineering
Nyckelord
- optimization
- grade change
- polymer
- economy
Status
Published
Projekt
- PICLU
Forskningsgrupp
- LCCC
ISBN/ISSN/Övrigt
- ISSN: 1873-4375