SIL verification and re-validation for LNG receiving terminal in operation

doi:10.11949/j.issn.0438-1157.20150721

Abstract

Abstract:

As the earliest in-service LNG terminal in China, GDLNG terminal had adding/modifying some equipments and safety instrumented function (SIF) after five years' heavy duty operation.To ensure the integrity and reliability of the safety instrumented system (SIS) in terminal, and the availability under heavy duty operation, terminal had performed Hazard and operability study (HAZOP).Based on the hazardous scenarios identified in HAZOP, Safety integrity level (SIL) classification, SIL verification and SIL re-validation had been performed to LNG terminal.The SIL classification is using layer of protection analysis (LOPA) method, which is less conservative than risk graph method used in design phase.According to SIL verification result, some SIFs in the terminal can not match SIL classification requirement.Sensitivity analysis had been performed to those SIFs.Impacts of optimizing SIS system configuration (without component hardware change, i.e., proof test interval, proof test coverage etc.) to the probability of failure on demand (PFD) had been studied.According to the sensitivity study result, SIL level can be somehow modified without component hardware change.Under certain circumstance, it can help us to a more cost-effective approach to fulfill company SIL requirement or risk acceptance criteria.Key technical points/difficulties and its possible solutions with SIL verification study are summarized, as well as the prospective development of SIL study.

Key words: natural gas, process control, safety instrumented system, SIL validation, PSMSuite^®, , Markov model, sensitivity study

摘要：

广东大鹏LNG接收站作为中国最早投用的LNG接收站,在5年的高负荷运行后中新增并改造了部分设备及功能安全回路(SIF),为确保接收站功能安全仪表系统(SIS)的完整性与可靠性以及高负荷生产的可用性,对所有生产设施及管线场站进行了HAZOP分析,并在HAZOP分析的基础上进行了SIL定级及再验证(re-validation)工作。本文以SIL再验证工作为例介绍SIL验算/再验证在在役装置中的应用,以及如何通过敏感性分析优化SIS系统配置与校验管理,满足企业风险可接受标准,最后总结并展望了实施SIL验算工作中的技术难点和未来的技术方向。

关键词: 天然气, 过程控制, 安全仪表系统, SIL验证, PSMSuite^®, , 马尔可夫算法, 敏感性分析

CLC Number:

YUAN Xiaojun, LU Yi, ZHENG Shifu. SIL verification and re-validation for LNG receiving terminal in operation[J]. CIESC Journal, 2015, 66(S2): 271-278.

袁小军, 鲁毅, 郑士富. 在役LNG接收站的SIS系统再验证[J]. 化工学报, 2015, 66(S2): 271-278.

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