油气储运设施事故风险指数模糊逻辑评估方法

油气储运设施风险是其事故发生概率和事故后果的综合度量,而事故概率和后果的定量评估结果往往是具有不确定性的数据,以确定性风险评估准则为基础的传统风险矩阵法和风险值法显然难以评估油气储运设施风险。为此提出开展油气储运设施事故风险的模糊逻辑推理法,首先,对风险矩阵的概率语言等级和损失语言等级的边界进行定量划分;然后,建立油气储运设施风险矩阵模糊集和模糊逻辑推理规则;最后,通过风险模糊推理运算和模糊风险解模糊化以确定油气储运设施的风险水平。实例应用与分析表明,利用推荐方法可得到较为详尽的风险数据信息,不但风险指数更加清晰,而且其所属风险等级类别也更加明确,评估结果能更好地指导油气储运设施的风险管理。

Fuzzy logic inference method for the accident risk probability matrix of the oil-gas storage installations

This paper intends to bring about a fuzzy logic inference method of OGSI's accident risk indexes,while we would like also to study the fuzzy logic theory based on the fuzzy sets in dealing with the information processing and uncertainty reasoning due to the accident probability and consequence improper or uncertain for accurate and imprecise calculations.For example,it wouldn't be convenient and possible to measure or examine the exact risk levels of the oil and gas storage and transportation installations in terms of a combination of the accident probability and its consequence.In the evaluation practice,however,it is also necessary to provide the actual quantitative assessment results.Therefore,it is obvious that,two most widely used assessment approaches can be adopted based on the deterministic assessment criteria,though they are full of uncertainty and imprecision.Hence,this paper tends to focus itself on the fuzzy logic inference of the OGSI's accident risk indexes.And,then,it is also necessary to introduce here the 7 × 5 cells standard matrix,representing a typical risk matrix encountered in many processing industries.For the said research purpose,it is necessary to quantify the linguistic scales of the 7 probability categories and 5 consequence categories of the said risk matrix,with a monetary quantification for the consequence loss of OGSI's accident being introduced,here,too.For instance,we have to apply the Gaussian type of membership function with the good nonlinear characteristics to establish the fuzzy sets of the OGSF's risk assessment matrix.What is more,it is also necessary to establish the fuzzy inference rules by joining the 7 × 5 cells matrix and the basic form of fuzzy If-Then rules so as to identify and depict the relation among the OGSI's accident probability,loss and risk categories.And,finally,it is also in need to transform the fuzzy sets of the accident probability and accident loss into fuzzy sets of the risk index through Mamdani fuzzy inference engine and fuzzy relationships in fuzzy If-Then rules.Besides,it is also in need to bring about the central average defuzzification technique to get the crisp index of OGSI's accident risk.Thus,in comparison with the traditional approach,it can be found that the method we have proposed can provide more risk-involving data with more precise risk indexes and more explicit risk categories.Thus,in conclusion,we can deduce that the method somehow overcomes the defects of the traditional risk matrix approach,and will be of help for making more accurate designs of the OGSI's risk management and the risk decision making.