LDPE装置管式反应器紧急泄压联锁系统可靠性分析

Research on Reliability of Emergency Relief System of LDPE Tubular Reactor

低密度高压聚乙烯(LDPE)装置反应系统的安全与紧急泄压系统的安全与可靠性密切相关。为评估紧急泄压安全联锁系统的安全要求及可靠性,采用精确的过程安全分析方法,对LDPE装置管式反应器紧急泄压联锁系统执行机构的冗余要求进行了分析。通过对泄压阀的开启及对泄压影响的研究,提出了LDPE反应器自分解泄压方程的修正模型,采用数值仿真方法研究了反应器内不同管段及全线自分解时紧急泄压阀开启数量、开启速度对反应泄压的关系。得出五取二以上的紧急泄压阀开启可以满足反应系统的紧急泄压要求。本研究结果确定了紧急泄压联锁系统执行机构的安全要求,为LDPE装置的联锁系统的安全完整性评估(SIL)提供了技术依据。文中还提出了反应过程的泄压系统设计要求,对提高装置的安全完整性具有借鉴意义。

The safety integrity of reaction system of low density polyethylene（LDPE） plant is mainly depending on the availability of emergency relief system.A state-of-the-art precise process safety analysis method was applied to evaluate the redundancy requirement of emergency relief valves of LDPE plant.Took relief valve opening characteristic into consideration,a modified emergency relief model was proposed by revising of the pressure relief model which was put forward by DuPont.Numerical simulation method was used to study run away situation in tubular reactor.The pressure fluctuation in reactor under different run away situations,e.g.relief valves operation strategy,valve operation speed as well as run away location were also studied.The conclusion of 2 out of 5 required relief valves under decomposition situation was obtained,which was benefit for the assessment of safety integrity level（SIL） of emergency SIS system.Detailed safety requirement specification of pressure relief system for reaction process was also discussed,which was benefit for improvement of safety integrity of process installations.