A simulated annealing optimization algorithm based nonlinear model predictive control strategy with application

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A simulated annealing optimization algorithm based nonlinear model predictive control strategy with application M. Mallaiah1 · K. Rama Rao2 · Ch. Venkateswarlu1  Received: 16 September 2019 / Accepted: 24 August 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020

Abstract Batch reactors are widely used in the production of fine chemicals, polymers, pharmaceuticals and other specialty products. For certain exothermic reactions, the transient operation of the reactor with respect to small changes in critical parameters like coolant temperature and initial composition of the reactants can lead runaway condition of the reactor. In order to avoid the hazards associated with runaway situations, it is imperative to operate the reactor by means of an efficient controller. This work presents a nonlinear model predictive control (NMPC) strategy based on simulated annealing (SA) for the temperature control of a batch reactor involving a highly exothermic runaway reaction. The efficacy of the proposed strategy is studied through simulation for the temperature control of the reactor in which a highly parametric sensitive exothermic reaction of hydrolysis of acetic anhydride with sulfuric acid as catalyst and acetic acid as a solvent is carried out. The controller is found effective in averting the runaway behavior with the smooth and quick attainment of the desired operating condition. The results demonstrate the better performance of the SA based NMPC over the linear model predictive controller (LMPC). Keywords  Exothermic batch reactor · Nonlinear model predictive control · Runaway reaction · Simulated annealing

1 Introduction Batch reactors are most commonly used in the production of fine chemicals, polymers, pharmaceuticals and other specialty products. Control of batch reactor is a challenging task, especially when exothermic chemical reactions takes place in the reactor (Rotstein and Lewin 1992). The excessive heat generated in the reactor due to such reactions makes it to exhibit highly nonlinear dynamic behaviour and may lead it to thermal runaway situation. Due to this, the system becomes parametrically sensitive where small changes in critical parameters like coolant temperature and initial composition of the reactants can cause drastic change in the dynamic behavior of the system (Jutan and Uppal 1984). To avoid the hazardous thermal runaway situation and its after effects, it is required to operate the reactor by means of an efficient controller. Conventional * Ch. Venkateswarlu [email protected] 1



Department of Chemical Engineering, B.V. Raju Institute of Technology, Narsapur, India



Petroleum and Chemical Engineering, Universiti Teknologi Brunei, Gadong, Brunei Darussalam

2

PID controllers are found unsatisfactory in the control of highly exothermic batch reactors with complicated inherent nonlinear dynamics (Aziz et al. 2000). To overcome the inadequacy of conventional controllers, various advanced controllers such as nonlinear adaptive control (Rotstein and Lewin 19