Abstract: The protective layer analysis (LOPA) method was used to identify the effectiveness of each protective layer in the dangerous scenario of high pressure string and low pressure in petrochemical plant. The LOPA method and its characteristics are introduced, and the failure data of various dangerous scenarios are compared according to the actual transformation cases. The total protection layer failure data is calculated according to the LOPA Settings in different series pressures. By exploring the better series pressure transformation scheme, the risk reduction in different scenarios can be identified effectively, and reasonable and effective improvement measures can be selected, which provides a theoretical basis for the high pressure series low pressure transformation of petrochemical equipment

Key words: high pressure string to low pressure, layers of protection analysis, independent protective layer, common cause failure

摘要： 针对石化装置高压串低压的危险场景，采用保护层分析(LOPA)方法识别危险场景中各个保护层的有效性。介绍了LOPA方法及其特点，并结合现场实际改造案例对比各危险场景的失效数据，根据不同串压中的LOPA设置情况，计算总的保护层失效数据。通过探讨更优的串压改造方案，进行有效地辨识不同场景下的风险消减，选择合理有效的改进措施，为石化装置高压串低压改造提供了理论依据

关键词: 高压串低压, 保护层分析, 独立保护层, 共因失效