(38b) Combined Use of High and Low Fidelity Models for Refinery-Wide Simulation

Use of models to make refinery-wide decisions, such as optimize crude purchase is sought after. In the last few years, process simulators have made significant advances to enable process engineers extend scope of process simulations beyond individual process units. It is however true that process simulators have usually been thought in terms of rigorous first-principle models to model process units - which in turn is expected to bring more accurate results for design. Scaling up these first principle models across the refinery to build refinery-wide models to model refinery operations requires significant amount of investment in terms of personal as well as computing infrastructure. This therefore results in very limited use of such models to make refinery-wide decisions by process engineers. There have been developed approaches which combine use of simplified as well as rigorous first principle models to make refinery-wide decisions. This approach includes using first principles models where necessary and filling in gaps with lower fidelity models. Key challenges in such an approach involves maintaining consistency at boundaries where once transitions from a high fidelity to a lower fidelity model and vice-versa. Some examples will be demonstrated within this paper.