重整加热炉模糊故障树分析研究

Fuzzy Fault Tree Analysis of Reforming Furnace

应用模糊故障树分析方法研究了连续催化重整装置中三合一组合式加热炉的可靠性.以重整加热炉工艺失常为顶事件,建立故障树,采用上行法定性分析找出该故障树的31个最小割集.引入模糊集理论中的模糊数概念,采用尖型L-R模糊数描述故障树中各底事件的发生概率.按照模糊逻辑门的运算法则定量计算故障树各中间事件及顶事件的发生概率区间.在各中间事件中,炉管故障的发生概率最高,且辐射室炉管故障明显高于对流室,从而确定出辐射室炉管为加热炉的薄弱环节.研究结果表明:对于很难或无法获得底事件发生概率准确值的石油化工设备而言,模糊故障树是一种有效实用的可靠性分析方法,与传统的故障树方法相比,计算得出的结果更加科学合理,更接近工程实际.

Reliability of the furnace in an existing industrial continuous catalytic reforming unit was investigated with the fuzzy fault tree analysis method.A fault tree was developed considering failure of the reforming furnace to be a top event.Thirty-one minimum cut sets were achieved by qualitative analysis with the ascending method.The concept of fuzzy number of the fuzzy sets theory was applied to describe the probability of basic event occurrence in the fault tree,and the fuzzy failure probabilities of the middle events and the top event were calculated with fuzzy AND and OR operators.Among all middle events the probability of tube failure is highest,and the tube failure probability in the radiant chamber is clearly higher than that in convection chamber,showing that the radiant chamber tube is a weak part in the furnace.The results show that the fuzzy fault tree proposed is an effective method of reliability analysis for petrochemical equipments and its calculation results are more reasonable than those of the conventional fault tree.