基于光纤传感技术对天然气储罐泄漏的在线监测研究

发布时间：2018-05-18 18:22

本文选题：光纤传感 + 立式液化天然气储罐　；参考：《江西理工大学》2017年硕士论文

【摘要】：近年来因立式液化天然气储罐发生泄漏而导致的火灾爆炸事故在全球各地常有发生。一旦发生该类事故将极有可能造成人员的伤亡及大量的财产的损失,不仅严重威胁到人员的生命安全,同时对周边环境造成巨大影响。因此利用光纤温度传感测温技术针对立式液化天然气储罐外壁温度场进行实时的在线监测研究,可以较好地掌握储罐内液化天然气泄漏过程中储罐外部温度场的变化规律,并准确的找到泄漏区域,为安全管理人员针对天然气储罐破裂等情况所造成的液化天然气泄漏扩散做出及时的预防控制及补救措施提供必要的技术性指导。为企业减少安全风险并使生产达到本质安全提供保障。为了更好的研究立式液化天然气储罐的泄漏扩散所造成的周边环境温度变化规律,建立泄漏时期立式液化天然气储罐外壁温度场变化的数学模型,再基于分布式光纤温度传感技术定位原理,对立式天然气储罐进行合理的模拟光纤缠绕布置。通过光-电信号的转化将泄漏时期立式天然气储罐表面的温度场变化情况模拟展现出来。最后根据所反映的泄漏时期泄漏口区域及相关检测区域环境温度随泄漏时间曲线变化图的显示,得出当储罐中发生液态天然气泄漏时储罐外壁温度场的变化规律。最后进行分析并得出相应结论:在设定边界条件及基本假设的前提条件下,通过感温光纤监测所得的储罐外壁温度曲线在储罐泄漏时刻出现明显下降。并且距离泄漏口越近,温度下降越剧烈,温度发生改变所需时间越短,距离泄漏口越远,发生温度下降变化越小,温度发生变化所需时间越长。而同样泄漏口周边温度场也随距离泄漏口距离的远近呈现不同程度的降低变化。由于只有液化天然气泄漏发生后发生气化吸热,才会导致储罐外壁环境温度出现明显降低变化。因此可以判定该时刻立式液化天然气储罐发生了泄漏,并且可以通过光纤温度传感定位技术准确找出泄漏区域。给安全工作人员提供技术参考,为储罐的安全运行提供保障。
[Abstract]:In recent years, fire and explosion accidents caused by leakage of vertical LNG storage tanks occur all over the world. Once this kind of accident occurs, it is very likely to cause casualties and a large number of property losses, which not only seriously threatens the safety of personnel, but also has a great impact on the surrounding environment. Therefore, the temperature field of vertical liquefied natural gas tank can be monitored in real time by using optical fiber temperature sensor to monitor the temperature field of the external wall of the tank, and the variation of temperature field of the tank during the leakage of liquefied natural gas in the tank can be well grasped. It also provides necessary technical guidance for safety management to make timely preventive control and remedial measures for LNG leakage and diffusion caused by natural gas tank rupture and so on. For enterprises to reduce safety risks and make production to achieve essential safety to provide security. In order to better study the variation of ambient temperature caused by the leakage and diffusion of vertical LNG tank, the mathematical model of temperature field change on the outer wall of vertical LNG tank during the leakage period is established. Based on the principle of distributed optical fiber temperature sensing technology, a reasonable simulation fiber winding arrangement is carried out for the natural gas storage tank. The temperature field on the surface of vertical natural gas tank during the leakage period is simulated by photo-electric signal conversion. Finally, the variation law of temperature field on the outer wall of the tank when the liquid natural gas leak occurs in the tank is obtained according to the diagram of the environmental temperature changing with the leakage time curve of the leak opening area and the related detection area in the leakage period. At last, the conclusion is drawn: under the premise of setting boundary conditions and basic assumptions, the temperature curve of the outer wall of the tank monitored by temperature sensing fiber can obviously decrease at the time of tank leakage. And the closer to the leak, the more drastic the temperature drop, the shorter the time required to change the temperature, the farther away from the leak, the smaller the temperature drop, the longer the temperature change. At the same time, the temperature field around the leak also varies with the distance from the leak. Only after the leakage of liquefied natural gas (LNG), gasification and heat absorption will lead to a significant decrease in the temperature of the external wall of the tank. Therefore, it is possible to determine the leakage of the vertical LNG tank at this time, and to find out the leakage area accurately by the optical fiber temperature sensing technology. Provide technical reference for safety workers and guarantee safe operation of storage tank.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE88

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