Maximizing Profit of Semi Batch Autocatalytic Esterification Process in the Presence of Disturbance: Application of Cascaded-Conditional Based Online Dynamic Optimization

Abstract

Abstract This work addresses the implementation of an online dynamic optimization cascaded with a dual mode PID control strategy for improving the product quality and profit of an autocatalytic esterification of Propionic Anhydride with 2-Butanol. An orthogonal collocation method is implemented to re-optimize the feed rate and temperature trajectories to compensate the deviation of end product due to disturbance (variation of feed concentration). The problem of dynamic optimization is formulated to maximize the profit. The spec of final product (±5% of conversion) constraint is denoted as an active constraint which is applied as the trigger for activating re-optimization. The simulation results show that the proposed strategy offers a large improvement in semi batch reactor performance if compared to the method which the optimal trajectories set point is pre-determined (offline). Moreover, the online dynamic optimization of temperature and feed flowrate trajectories obtained able to sustain the limiting reactant concentration within active constraint. Meanwhile, the offline optimization failed to handle the effect of disturbance thus the end concentration produced is off-spec and can lead to loss in profit.