基于风险的检验（RBI）用于LNG储罐风险评估的改进研究

发布时间：2018-04-14 21:36

本文选题：LNG储罐 + 风险评估　；参考：《西南石油大学》2017年硕士论文

【摘要】：液化天然气(LNG)技术使得天然气以液态形式存在,方便了天然气的存储和运输,而且促进了天然气贸易,推动了天然气应用的发展。液化天然气既具有天然气易燃易爆的特点,同时还具有低温液体所特有的低温特性,一旦发生泄漏,将会导致严重的后果,对设备、企业、环境以及人们的生命安全造成严重的威胁。因此在LNG的存储中,LNG储罐泄漏失效就成了需要重点考虑的问题。基于风险的检验(RBI)是通过对检测结果的分析,确定导致缺陷发生的原因,并采用相应的措施进行预防,从而降低设备的风险。API 581资源文件提供了石化企业基于风险的检验方法。而API 581中的失效数据来源于欧美26家石化企业压力容器的历史失效数据并按统计学原理建立,由于我国与发达国家相比,存在工艺水平较低、材料性能较差以及超期服役现象,就导致API 581建议的通用失效频率并不能有效的用于我国LNG储罐的风险评估。针对这个问题,利用映射变换法对LNG储罐的通用失效频率进行修正,使之能更好的适用于我国LNG储罐的风险评估实际情况。通过建立LNG储罐泄漏事故树并进行分析,得到LNG储罐泄漏事故树最小割集与结构重要度,确定LNG储罐泄漏失效系统的薄弱环节,提高了检验的针对性,有效降低检验成本。利用贝叶斯网络对LNG储罐泄漏失效事故树中底事件的二态性进行修正。最后,通过DNV PASTSAFETI软件对某LNG储罐泄漏失效后果进行模拟分析,并将模拟得到的不同泄漏孔径下的失效后果面积和利用修正后的模型计算得到的后果面积用于风险计算公式,进行对比分析,验证了修正模型的正确性。
[Abstract]:Liquefied natural gas (LNG) technology makes natural gas exist in liquid form, which facilitates the storage and transportation of natural gas, promotes natural gas trade and promotes the development of natural gas application.Liquefied natural gas not only has the characteristics of flammability and explosion of natural gas, but also has the characteristic of low temperature liquid. Once leakage occurs, it will lead to serious consequences for equipment, enterprises,The environment and the safety of people pose a serious threat.Therefore, the leakage failure of LNG storage tank becomes an important problem to be considered.Risk-based testing (RBI) is based on the analysis of test results to determine the causes of defects and to take appropriate measures to prevent them, thus reducing the risk of equipment. API 581 resource file provides a risk based inspection method for petrochemical enterprises.The failure data in API 581 are derived from the historical failure data of pressure vessels in 26 petrochemical enterprises in Europe and America and established according to the principle of statistics.The general failure frequency suggested by API 581 is not effective for risk assessment of LNG tanks in China.In order to solve this problem, the general failure frequency of LNG tanks is modified by mapping transformation method, which is more suitable for the risk assessment of LNG tanks in China.By establishing and analyzing the LNG tank leakage accident tree, the minimum cut set and structural importance of the LNG tank leakage accident tree are obtained, the weak links of the LNG tank leakage failure system are determined, the pertinence of the inspection is improved, and the inspection cost is effectively reduced.Bayesian network is used to modify the bimodality of bottom events in LNG tank leakage failure tree.Finally, the DNV PASTSAFETI software is used to simulate and analyze the leakage failure consequences of a certain LNG tank, and the failure consequence area under different leakage aperture and the result area calculated by using the modified model are used in the risk calculation formula.The correctness of the modified model is verified by comparison and analysis.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE972

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