Browsing by Author "Rehail Yasser Zennir Youcef Tchouar Noureddine"

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    An Integrated Approach to Safety Instrumented System Lifecycle Management: Risk Evaluation and Optimization in the Petrochemical Industry Using Genetic Algorithms
    (Instrumentation Mesure Métrologie Vol. 24, No. 1, February, 2025, pp. 23-34, 2025-02-28) Rehail Yasser Zennir Youcef Tchouar Noureddine
    This study aims to present a complete methodology that integrates evaluation and optimization to address the entire Safety Instrumented Systems (SIS) lifecycle. A comprehensive methodology for SIS evaluation and optimization is proposed, specifically targeting a system, called I-1165, responding to a high-high level alarm in a De-ethanizer Reflux Drum V-2, which is used to separate ethane and lighter components from heavier hydrocarbons. The methodology begins with a comprehensive HAZOP study to identify and assess potential risks, which are then estimated using PHAST software. SIL allocation is performed using the LOPA method, followed by the determination of Achieved SIL through analytical formulas. The Achieved SIL is iteratively validated by comparing it with the Required SIL. If the Achieved SIL does not meet the required standards, a genetic algorithm (GA) is employed to optimize the SIS design and maintenance strategies. This process continues until the target SIL is achieved, or an alternative architecture is proposed, ensuring that the SIS performance aligns with safety requirements. Optimization results for the I-1165 system reveal a significant improvement in PFDAvg from 2.1E-2 to 6.10537E-4, meeting and exceeding the required SIL 2 performance. This improvement not only enhances system safety and reliability but also ensures compliance with IEC 61508 standards while reducing lifecycle costs by optimizing the frequency of maintenance and testing intervals.