A Hierarchical Optimization Approach to Optimal Production Scheduling in an Industrial Continuous Olefin Polymerization Reactor

Authors

  • Christos Chatzidoukas,

    1. Chemical Process Engineering Research Institute, CERTH, Thessaloniki, Greece
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  • Stratos Pistikopoulos,

    1. Center for Process Systems Engineering, Department of Chemical Engineering, Imperial College, London SW7 2AZ, UK
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  • Costas Kiparissides

    Corresponding author
    1. Department of Chemical Engineering, Aristotle University of Thessaloniki and Chemical Process Engineering Research Institute, P.O. Box 472, 54124, Thessaloniki, Greece
    2. Chemical Process Engineering Research Institute, CERTH, Thessaloniki, Greece
    • Department of Chemical Engineering, Aristotle University of Thessaloniki and Chemical Process Engineering Research Institute, P.O. Box 472, 54124, Thessaloniki, Greece. Fax: +30 2310 99 6198
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Abstract

The time-optimal grade-transition policies, as well as the selection of the optimal grade production sequence, are calculated for a gas-phase ethylene/but-1-ene copolymerization FBR. The tuning parameters (i.e., proportional gain and integral time) of the feedback PI process controllers, as well as the time-optimal trajectories of the feedforward controllers, are treated as decision variables. A two-level decomposition approach is applied for solving the optimal-grade transition-scheduling problem, taking into account the impact of both transient operation and the sequence of grade transitions on the overall amount of off-spec polymer and overall transition time.

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