Optimization and control of a continuous polymerization reactor

Abstract

-This work studies the optimization and control of a styrene polymerization reactor. The proposed strategy deals with the case where, because of market conditions and equipment deterioration, the optimal operating point of the continuous reactor is modified significantly along the operation time and the control system has to search for this optimum point, besides keeping the reactor system stable at any possible point. The approach considered here consists of three layers: the Real Time Optimization (RTO), the Model Predictive Control (MPC) and a Target Calculation (TC) that coordinates the communication between the two other layers and guarantees the stability of the whole structure. The proposed algorithm is simulated with the phenomenological model of a styrene polymerization reactor, which has been widely used as a benchmark for process control. The complete optimization structure for the styrene process including disturbances rejection is developed. The simulation results show the robustness of the proposed strategy and the capability to deal with disturbances while the economic objective is optimized.

Modifier Adaptation for Real-Time Optimization—Methods and Applications

“…(ii) Can one use the gradient information obtained for MA in the MPC layer? While there are answers to Question (i) [45,105]; Question (ii) remains largely unexplored. This also raises the research question of how to design (static) MA and (dynamic) process control in a combined fashion or, expressed differently, how to extend the MA framework toward dynamic RTO problems.…”

Economic optimality in MPC: A comparative study

“…The polymerization reactor is usually the heart of the polymer production process and its operation may be difficult as it involves exothermic reactions, unknown reaction kinetics and high viscosity [3]. Most styrene polymers are produced through batch or continuous polymerization processes.…”

A Modifier-Adaptation Strategy towards Offset-Free Economic MPC

“…As underlined above, the RTO and MPC hierarchical division issue has led to the increased interest in merging the two layers. Many works in the literature consider a combination between RTO and MPC through a target calculation level in the middle that coordinates the communication and guarantees stability to the whole structure calculating the feasible target for the optimal control problem [17,18]. There are also examples of integration between the modifier-adaptation technique and MPC [19]: in this way, the input targets calculated by the MPC are included as equality constraints into the modified RTO problem.…”