Application of Surrogate Models as an Alternative to Process Simulation for Implementation of the Self-Optimizing Control Procedure on Large-Scale Process Plants—A Natural Gas-to-Liquids (GTL) Case Study
Vahid Khezri, Mehdi Panahi, Elham Yasari, Sigurd Skogestad
Abstract
High computational loads, time-consuming convergence, and simulation crashes are common when using process simulators for flowsheet optimization. In this paper, by replacing the large-scale physical process simulations by surrogate models, the optimization time and computational load are reduced significantly along with maintaining the accuracy and reliability. A gas-to-liquids (GTL) plant was used as a large-scale process plant case study. The multilayer perceptron neural network (MLP-ANN), radial basis function neural network, support vector machine, and adaptive neuro-fuzzy inference system models were selected as alternative surrogate models. These alternatives were investigated for implementation of the self-optimizing control procedure on the above case study to find the best individual and combined self-optimizing controlled variables. The MLP-ANN surrogate model showed the best performance in predicting the optimum points and for selecting the best self-optimizing CVs. In fact, it even performed better than using the full process simulator.