Optimization approaches to the integrated system of catalytic reforming and isomerization processes in petroleum refinery

In this paper, we deal with the optimization of a cluster comprising two key processes in petroleum refinery: catalytic reforming, and light naphtha isomerization. We propose a novel hybrid methodology which combines direct and indirect approaches. In the direct approach we consider the complete kinetic model and we adopt derivative-free approaches since the analytic expression of the model is not available. In the indirect approach we propose a surrogate modelling based optimization and we apply state-of-the-art solver to retrieve the optimal operating condition and flowsheet configuration of the process. The hybrid method consists of two steps: (i) we compute different good feasible solutions by means of the indirect approach, and (ii) we apply the direct approach using the solutions of the previous step as starting points. Computational experiments for different scenarios are finally discussed.