大型LNG储罐安全性分析及检验监控方法研究

发布时间：2018-03-23 14:45

本文选题：大型LNG储罐　切入点：安全性分析　出处：《首都经济贸易大学》2013年硕士论文

【摘要】：随着天然气产业的发展,多座接收站用大型LNG储罐正在沿海地区服役及兴建。我国大型LNG储罐建造技术刚刚起步,各相关规范正在建立与完善阶段。介于LNG储罐存储容量大、存储介质危险、存储条件特殊等原因,对储罐运行过程中的安全性分析与检验、监控方面的研究亟待深入。本文对典型16万立方米LNG全容储罐结构、安全性及检验监控方法进行研究： (1)储罐安全性分析储罐事故类型包括火灾、爆炸、窒息、冷爆炸等,利用ALOHA软件模拟储罐结构失效后果发现储罐发生火灾爆炸事故的后果最为严重。从内部因素、外部因素及点火源三个方面分析引起储罐事故的危险因素,采用FTA方法分析储罐火灾爆炸事故的原因事件并进行重要度排序,得出引起火灾爆炸事故的17个基本事件中与监控、检验效果有关的基本事件重要度最高,其次为与储罐结构完整性相关的其他基本事件。 (2)储罐有限元分析利用ANSYS有限元软件分析储罐结构的薄弱环节。分析了9%Ni钢内罐LNG充装满罐、半罐和空罐三种情况,得出内罐最下层壁板的应力应变最为集中。对混凝土外罐进行静力与地震惯性力加载分析,因拉应力对预应力混凝土外壁结构影响较大,最大拉应力集中出现在储罐外壁与罐顶结合部位的环方向以及安全停机地震时罐壁底侧的竖向上。得出混凝土罐壁底侧、罐顶下沿的强度需要重点监测与检验,内罐最下层底板在正常工作条件下应进行重点监控检验的结论。 (3)检验监控方法研究大型LNG全容储罐在正常运行阶段不能进行开罐检验,只能进行在线检验,对储罐的检验包括：内衬钢板预应力混凝土结构外罐应采用超声回弹综合法检验混凝土强度；预应力水平利用形变压力测读与预应力筋强度监测的方法检测；内罐与外罐内衬钢板的腐蚀程度应采用声发射检验等。针对所分析储罐危险因素分析了大型LNG储罐的监控方法,监控内容包括内部压力监控,LNG分层趋势的监控,液位监控以及火灾监控等。利用RBI技术可对LNG储罐检验部位、方法和周期进行决策和优化,并可实现降低储罐控制阀门等监控设施失效风险的目的。
[Abstract]:With the development of natural gas industry, large LNG tanks used in many receiving stations are in service and construction in coastal areas. The construction technology of large LNG tanks in China is just beginning, and the relevant specifications are being established and perfected. Because of the danger of storage medium and the special storage condition, the research on safety analysis and inspection and monitoring of storage tank is urgently needed. In this paper, the structure, safety, inspection and monitoring methods of a typical 160000 cubic meter LNG full capacity storage tank are studied. Safety analysis of storage tank. The types of tank accidents include fire, explosion, asphyxiation, cold explosion and so on. Using ALOHA software to simulate the consequences of tank structure failure, it is found that the consequences of tank fire and explosion accidents are the most serious. The external factors and ignition sources are used to analyze the dangerous factors causing the tank accidents, and the FTA method is used to analyze the cause events of the tank fire and explosion accidents and to rank the importance of the accidents. The 17 basic events causing the fire and explosion accidents and their monitoring are obtained. The importance of the basic events related to the inspection effect is the highest, followed by other basic events related to the structural integrity of the tank. Finite element analysis of storage tank. ANSYS finite element software is used to analyze the weak links of the storage tank structure. The LNG filling tank, half tank and empty tank of 9%Ni steel inner tank are analyzed. It is concluded that the stress and strain of the bottom wall of the inner tank are the most concentrated. The static and seismic inertial force loading analysis of the concrete outer tank is carried out because the tensile stress has a great influence on the prestressed concrete outer wall structure. The maximum tensile stress concentration occurs in the annular direction of the joint between the outer wall of the tank and the top of the tank and the vertical elevation of the bottom side of the tank wall during the safe shutdown earthquake. It is concluded that the strength of the bottom side of the concrete tank wall and the bottom edge of the tank roof need to be monitored and checked. The conclusion that the bottom plate of the inner tank should be monitored and inspected under normal working conditions. Research on Inspection and Monitoring method. Large LNG full capacity storage tank can not be opened in normal operation, but can only be tested on line. The inspection of storage tank includes: the ultrasonic rebound comprehensive method should be used to test the strength of concrete in the external tank of prestressed concrete structure with steel plate lining; The pre-stress level is measured by deformation pressure reading and the strength of prestressing tendons is monitored, the corrosion degree of inner and outer tank lining steel plates should be examined by acoustic emission test, and the monitoring method of large LNG storage tank is analyzed in view of the risk factors of the tank analyzed, and the corrosion degree of the inner lining steel plate of the inner and outer tank should be examined by acoustic emission test. The monitoring contents include internal pressure monitoring, liquid level monitoring and fire monitoring, etc. RBI technology can be used to make decision and optimize the inspection position, method and period of LNG storage tank. The purpose of reducing the failure risk of tank control valves and other monitoring facilities can be achieved.
【学位授予单位】：首都经济贸易大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：X937;TE88

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