多IE复杂事故场景的LNG储罐工艺HAZOP与LOPA-SIL风险评估

Risk assessment of multiple IE complex accident scenarios LNG storage tank process HAZOP and LOPA-SIL

采用HAZOP分析法找出了5个LNG储罐工艺偏差,通过分析偏差产生的原因与事故后果,筛选出LNG储罐液位高、压力大、包容物损失(泄漏)3个高风险事故场景,再引入“多IE(初始事件)引发单事故后果的复杂事故场景”LOPA分析法,通过进一步评估初始事件、保护层的有效性、其他安全措施,计算事故发生频率发现:LNG储罐现有安全措施还不够完善、安全仪表功能没有区分明确;对事故发生频率不满足风险等级要求的事件,建议增加相应SIL的安全仪表系统(SIS)减缓事故风险等级,使企业事故风险等级在可接受范围之内,提高工艺安全设计的合理性与可靠性。

HAZOP analysis is used to find out the process deviation of 5 LNG storage tanks.By analyzing the causes and accident consequences of the deviation,three high-risk accident scenarios of LNG storage tank high liquid level,high pressure and containment loss(leakage)are screened out.Then LOPA analysis is introduced to“complex accident scenario with single accident consequence caused by multiple IE”.By further evaluating the initial event,the effectiveness of protective layer and other safety measures,and calculating the frequency of accidents,it is found that the existing safety measures of LNG storage tanks are not perfect enough,and the safety instrument functions are not clearly differentiated.It is suggested that the safety instrument system(SIS)of SIL should be added to mitigate the risk level of accidents that do not meet the risk level requirements,so that the risk level of enterprises can be within the acceptable range,and the rationality and reliability of process safety design can be improved.