LNG加气站HAZOP定量分析方法研究

发布时间：2018-03-01 00:28

本文关键词： LNG加气站 HAZOP 定量分析偏差临界值 SDG模型后果严重度分析　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：LNG加气站一般建于城市边缘,一旦发生事故将造成严重的后果,所以采用危险辨识技术对LNG加气站潜在的危险进行分析,针对存在的危险提出有效的防治措施,防止发生事故是非常重要的。众多的危险辨识方法中,危险与可操作性分析(HAZOP)具有系统性、全面性、结构性、细致性等优势,所以,本文运用HAZOP对LNG加气站进行安全分析。HAZOP自问世以来,一直以定性的风险分析方法广泛应用于各个领域,但HAZOP定性分析存在诸多不足：不能明确指出所分析参数偏差的具体数值,即偏差模糊性大；分析所得结果针对性差,不能使工作人员明确系统的薄弱环节,从而抓住主要风险。故本文提出对LNG加气站进行HAZOP定量分析。本文提出的HAZOP定量分析方法是在定性分析的基础上进行的,所以文章首先介绍了HAZOP定性分析方法的原理和分析步骤,并以四川某LNG加气站为例进行分析。为了克服定性分析偏差模糊性大的缺点,本文提出界定偏差临界值,可根据LNG加气站工艺参数控制指标界定,对于不能由工艺指标确定的,采用HYSYS软件动态模拟偏差发生时对系统的影响,通过其他参数指标界定偏差临界值。为使HAZOP分析结果具有针对性,让人们明确LNG加气站的薄弱环节和主要危害,文章提出结合风险矩阵确定偏差风险等级。偏差风险等级由偏差发生可能性等级和偏差导致的后果严重度等级确定。由于SDG(符号有向图)与HAZOP推理机制类似,两种方法有着天然的联系,故将SDG与HAZOP结合。首先根据LNG加气站工艺流程画出SDG模型,再以发生偏差的参数所在节点为对象进行拉偏(偏离偏差临界值),找出所有偏差传播通路,原因事件概率用基于专家意见的模糊处理方法求得,传播变量概率用基于贝叶斯网络的SDG概率计算规则求得,便可计算偏差发生概率,进而确定偏差发生可能性等级。鉴于LNG加气站工艺流程的特殊性(同一设备用于不同工艺流程中),HAZOP分析的偏差不能以一笼统的值确定,偏差所致的后果也不同,本文提出将偏差后果分为工艺后果(影响工艺生产)和安全后果(偏差导致安全事故发生)两大类,当存在安全后果时,考虑安全后果,进行安全后果严重度评价；当偏差导致工艺后果而未引起安全事故时,进行工艺后果严重度评价。参考国内相关条例,并结合LNG加气站自身规模和特点进行了事故后果严重度等级划分,以确定偏差后果严重度等级。最后以四川某LNG加气站为研究对象,进行了HAZOP定量分析,辨识出LNG储罐超压是该加气站最大的潜在危害,符合现场运行情况,验证了本文提出的LNG加气站HAZOP定量分析方法的实用性。
[Abstract]:The LNG filling station is generally built on the edge of the city, once an accident occurs, it will cause serious consequences, so the potential hazard of LNG filling station is analyzed by using hazard identification technology, and effective prevention measures are put forward in view of the existing danger. Prevention of accidents is very important. Among many hazard identification methods, HAZOPhas the advantages of systematic, comprehensive, structural and meticulous, so, In this paper, HAZOP is used to analyze the safety of LNG filling station. HAZOP has been widely used in various fields with qualitative risk analysis method since its inception. However, HAZOP qualitative analysis has many shortcomings: it can not clearly point out the specific value of the deviation of the parameters analyzed. That is, the ambiguity of deviation is big, the result of analysis is poor, and the staff can not make clear the weak link of the system, so the main risk can be grasped. Therefore, this paper puts forward the HAZOP quantitative analysis of LNG filling station. The HAZOP quantitative analysis method proposed in this paper is carried out on the basis of qualitative analysis, so this paper first introduces the principle and steps of HAZOP qualitative analysis method. Taking a LNG gas station in Sichuan province as an example, in order to overcome the shortcoming of the ambiguity of qualitative analysis deviation, the critical value of deviation is proposed in this paper, which can be defined according to the control index of process parameters of LNG gas filling station, but can not be determined by the process index. HYSYS software is used to dynamically simulate the influence of deviation on the system, and the critical value of deviation is defined by other parameter indexes. In order to make the results of HAZOP analysis targeted, the weak link and main harm of LNG filling station are made clear. In this paper, it is proposed to determine the deviation risk grade by combining the risk matrix. The deviation risk grade is determined by the possibility class of deviation and the consequence severity grade caused by deviation. Because the HAZOP (symbolic directed graph) is similar to the reasoning mechanism of HAZOP, There is a natural connection between the two methods, so the SDG and HAZOP are combined. Firstly, the SDG model is drawn according to the process flow of the LNG filling station. Then taking the node where the parameter of the deviation occurs as the object to pull the deviation (deviating from the critical value of deviation) and finding out all the propagation paths of the deviation, the probability of the cause event is obtained by the fuzzy processing method based on the expert opinion. The probability of propagation variable can be calculated by using the SDG probability calculation rule based on Bayesian network, and the probability of occurrence of deviation can be calculated. In view of the particularity of the process flow of the LNG filling station (the deviation of the same equipment used in different processes cannot be determined by a general value, the consequences of the deviation are also different. In this paper, the deviation consequences are divided into two categories: process consequences (affecting process production) and safety consequences (resulting in safety accidents). When there are safety consequences, safety consequences are considered and the severity of safety consequences is evaluated. When the deviation causes the process consequence but does not cause the safety accident, carries on the craft consequence severity appraisal. Referring to the domestic related regulations, and combined with the LNG filling station own scale and the characteristic, the accident consequence severity grade is divided. To determine the severity of deviation consequences. Finally, taking a LNG gas station in Sichuan province as the research object, the HAZOP quantitative analysis is carried out, and it is identified that the overpressure of the LNG tank is the biggest potential hazard of the station, which is in line with the field operation. The practicability of the HAZOP quantitative analysis method proposed in this paper for LNG filling station is verified.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE88

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