聚乙烯醇罐区火灾爆炸事故树分析

Fault tree analysis of fire and explosion accidents in the PVA storage tanks

通过现场的调研与事故树分析相结合的手段对某厂聚乙烯醇车间聚合罐区火灾爆炸事故的危险因素进行了识别与分析。以该罐区可能发生的火灾爆炸事故作为顶上事件,对可能引发顶上事件的21个基本事件及一个条件事件构建事故树,利用最小割集、最小径集及结构重要性计算手段进行事故风险程度分析,从而确定醋酸乙烯暴聚是聚合罐区的首要危险源,而促发醋酸乙烯暴聚的物料长时间停留、气相氧含量过高、温度控制失效、阻聚剂含量不足等四个基本事件是导致聚合罐区火灾爆炸事故的最危险因素。本文对以上聚合罐区发生火灾爆炸事故的风险因素进行详细定性分析,并在此基础上有针对性的提出了相应的安全预防控制措施。同时,该聚合罐区的事故树分析结论也可以为同类别化工单位罐区的日常运行、设计改造、维护保养等工作提供理论依据。

According to the field investigation and fault tree analysis, the harmful factors which can cause the fire and explosion accident in the PVA storage tanks were analyzed. Taking fire and explosion accidents which may happen in the PVA storage tanks as the top event, the fault tree with 21 basic events and a conditional event that can lead to the top event was built. Then the level of accident risk was analyzed by some calculating methods, such as the least cut set, the least path set and the structure importance calculation, and it was ensured that terrible polynaerization of vinyl acetate was the first dangerous fact and the 4 basic events： long storage time, high oxygen content in gas phase, temperature control unserviceable, the lack of polymerization inhibitor were the most dangerous factors in the PVA storage tanks. A detailed qualitative analysis was made on the risk factors leading to the fire and explosion accidents in the PVA storage tanks. Based on the analysis, specific safety precaution and control measures were proposed. Meanwhile, the results of fault tree analysis can provide the similar chemical industry units with new theoretical basis for daily running, design modification and maintenance for the storage tanks.