Chemical, petrochemical, and refinery sectors have been facing tougher safety, environmental and mechanical integrity regulations as well as challenges associated with the need for cost reduction to improve competitiveness. Risk-based Inspection (RBI) is a cost-effective approach to manage operational risks by making an informed decision on inspection frequency, extent of inspections, and types of non-destructive testing. This paper presents a comprehensive practical risk model that can simulate all components of liquefied petroleum gas (LPG) tanks, that is, roof, shell, nozzles, and bottom plates. The probability of failure (PoF) model was developed based on failure frequency data from four different sources to determine the adequate general failure frequencies, moreover, it addresses the fatigue effect due to cyclic loading. Reviewing past losses of containment incidents revealed that fires and explosion are the most likely outcomes, therefore, this risk model introduced area affected consequence of failure (CoF) simulation. The CoF model addresses all the main components of the LPG tank and deploys a practical gas dispersion model to estimate the vapor cloud explosion (VCE) and flash fire consequence affected areas. Furthermore, modified mass release equations are presented to account for the decline in the release rate with time to determine the pool fire area and leak duration. Consequence areas are determined based on serious personnel injuries and component damage from thermal radiation and explosions. To validate the risk model, a proof of concept assessment was performed on seven tanks.

中文翻译：

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改进的液化石油气储罐完整性管理量化风险模型：数学基础和案例研究

化工、石化和炼油行业一直面临更严格的安全、环境和机械完整性法规以及与降低成本以提高竞争力的需求相关的挑战。基于风险的检查 (RBI) 是一种通过对检查频率、检查范围和无损检测类型做出明智决定来管理运营风险的经济高效的方法。本文提出了一个综合的实用风险模型，可以模拟液化石油气 (LPG) 储罐的所有部件，即顶盖、罐壳、喷嘴和底板。失效概率 (PoF) 模型是基于来自四个不同来源的失效频率数据开发的，以确定足够的一般失效频率，此外，它解决了循环载荷引起的疲劳效应。回顾过去的遏制事件损失表明，火灾和爆炸是最有可能的结果，因此，该风险模型引入了区域影响故障后果 (CoF) 模拟。CoF 模型解决了液化石油气罐的所有主要组件，并部署了一个实用的气体扩散模型来估计蒸气云爆炸 (VCE) 和闪火后果影响区域。此外，还提出了修正的质量释放方程，以解释释放速率随时间的下降，以确定池火灾面积和泄漏持续时间。后果区域是根据热辐射和爆炸造成的严重人员伤害和组件损坏确定的。为了验证风险模型，对七个坦克进行了概念验证评估。