Sensitivity of Vapor Cloud Explosion Exceedance Analysis to the Ignition Probability Model for Offshore Process Systems

Abstract

Probabilistic methodologies have been strictly recommended in the offshore field since the worst offshore explosion disaster in terms of lives lost in the North Sea in 1988. For todays offshore projects, essential design specifications including design loads for critical hazardous events are produced by quantitative risk analysis (QRA), which substantially governs the success of offshore projects. The offshore topside process systems are most vulnerable to hydrocarbon-relevant disasters such as vapor cloud explosion (VCE) and fire. However, it still remains extremely challenging to properly predict and mitigate the risk of such complex offshore topside systems, due to the nature of complexity in the system in addition to harsh environmental and operating conditions. Therefore, this study aims to advance the understanding of uncertainties and risk in the complex offshore systems exposed to multiple interrelated natural and man-made hazards (i.e. winds, VCEs). This study investigates the effects of uncertainties on the risk quantification focusing on VCE risk and ignition probability models, which has not been studied yet. A detailed probabilistic risk quantification of VCE is performed for a specific offshore topside system. The estimated design explosion load based on the VCE risk is compared for different ignition probability models.