An optimization approach to the integration of inherently safer design and process scheduling

This work introduces an optimization-based approach to the simultaneous consideration of process safety and process scheduling during the design phase. Expected variations in production schedule and associated environmental constraints are included early enough in the design phase. Additionally, safety metrics are used in screening and selecting design alternatives. The Dow Fire and Explosion Index is used as the safety-evaluation metric. An optimization formulation is developed to account for potential design and scheduling options while incorporating safety and environmental objectives. The proposed approach optimizes the process by establishing Pareto curves that demonstrate the tradeoff between the safety metrics and the economic objectives of the process. A case study on NOx removal in a refinery is solved to illustrate the applicability of the devised procedure.