基于HAZOP技术和风险图法的可燃气体爆炸下限监测与控制回路SIS设计

SIS Design of Combustible Gas Explosion Lower Limit Monitoring and Control Loop Based on HAZOP Technology and Risk Map Method

以蓄热式热氧化工艺处理化学原料药制造企业挥发性有机废气(VOCs)为背景,给出蓄热式氧化炉(RTO)系统关键设备SIS设计与验证的研究方法与关键步骤。基于HAZOP技术进行风险识别,利用风险图法进行风险评估与安全完整性等级(SIL)定级,依据GB/T 20438—2017、HJ1093—2020和苏应急〔2021〕46号进行安全仪表系统(SIS)设计,借助多阶段马尔可夫模型对SIS进行验证。结果表明:RTO系统首要安全风险在于过高浓度VOCs废气进入其装置而引发爆炸;设计SIS以确保进入RTO装置的VOCs废气浓度低于其爆炸极限下限的25%;SIS包括传感器、逻辑解算器和最终执行元件;SIS的PFDavg为1.32E-04,满足SIL3等级要求;SIS中传感器部分是最不可靠的。

Taking the treatment of VOCs waste gas from API manufacturing enterprises as an example,both research methods and key steps of SIS design and verification of key equipment of RTO system were proposed,including the risk identification based on HAZOP,risk assessment and SIL grading through the risk graph,SIS system design according to GB/T 20438—2017,HJ1093—2020 and Su Emergency〔2021〕No.46 and verifying SIS system by multi-stage Markov model.The results show that,the primary safety risk of RTO system was that the high VOCs may concentrate within RTO and the explosion may be incurred;SIS designed can ensure that the concentration of VOCs entering the RTO unit is below 25%of the lower limit of its explosion limit.The SIS system designed includes sensor,logic solver and final actuator;The PFDavg of the SIS system is 1.32E-04 which meeting SIL3 level and the sensor part of SIS system is the least reliable.