Robust planning of multisite refinery networks: Optimization under uncertainty

This paper considers the problem of multisite integration and coordination strategies within a network of petroleum refineries under uncertainty and using robust optimization techniques. The framework of simultaneous analysis of process network integration, originally proposed by Al-Qahtani & Elkamel [Al-Qahtani, K., & Elkamel, A. (2008). Multisite facility network integration design and coordination: An application to the refining industry. Computers & Chemical Engineering, 32, 2198], is extended to account for uncertainty in model parameters. Robustness is analyzed based on both model robustness and solution robustness, where each measure is assigned a scaling factor to analyze the sensitivity of the refinery plan and integration network due to variations. Parameters uncertainty considered include coefficients of the objective function and right-hand-side parameters in the inequality constraints. The proposed method makes use of the sample average approximation (SAA) method with statistical bounding techniques. The proposed model was tested on two industrial-scale studies of a single refinery and a network of complex refineries. Modeling uncertainty in the process parameters provided a practical perspective of this type of problems in the chemical industry where benefits not only appear in terms of economic considerations, but also in terms of process flexibility.