An innovative quantitative analysis methodology for Natech events triggered by earthquakes in chemical tank farms

Abstract

Natech events triggered by earthquakes are one of the major threats in chemical clusters. Earthquake can not only cause serious damage to equipment, but also hinder the rescue operations and exacerbate the evolution and escalation of accidents. In order to analyze the complicated domino accident scenarios under earthquake in chemical tank farms, an innovative quantitative analysis method is proposed. The algorithm based on Monte Carlo simulation for domino probabilities considers the multiple escalation vectors of the same accident unit and the synergistic effect of multiple escalation vectors from different units. Domino probabilities at different levels can be analyzed for specific primary scenario and overall scenarios. Two different rescue operation states considering and not considering the impact of earthquake are analyzed in case study. The results show that earthquake greatly increases the risk of chemical tank farm and rescue operations with longer time lead to higher domino probabilities due to higher escalation probabilities; the domino accident evolves faster and has higher probabilities in the primary scenario with multiple accident sources; the domino probabilities above third level are small for overall scenarios, especially in the case of high earthquake intensity. The methodology can also be applied to the analysis of complex specific accident scenarios and provide support for the setting of safety barriers and emergency resources.