Design And Research Of LNG Leakage Multi-point Monitoring And Positioning System

With the environmental pollution becoming more and more seriously,island shipping has put forward a new direction of energy saving and emission reduction,shipping environmentally.The liquefied natural gas(LNG)has the advantages of clean emission,high energy utilization low shipping costs and so on.So LNG has been vigorously promoted in island shipping process,as LNG is a kind of dangerous chemicals,it determined high safety request of the LNG filling stations.Considering the safety of LNG and monitoring various information of the LNG gas,the LNG filling barge monitoring system has been designed.In order to improve the performance and efficiency of the monitoring system,then precisely located the position of the leakage gas,this thesis made the following research.According to the hardware requirements of the monitoring system,we selected appropriate sensors and main control chip,designed the circuits of the power module,data acquisition module data transmission module and so on.Considering the data processing ability,the main control chip used the STM32 series STM32F103ZET6,in order to improve the detection sensitivity of the sensors,we chosen the fiber Bragg temperature sensor and fiber concentration sensor.In terms of software,we designed and developed the software monitoring interface by C# language.We should analyzed the collected data,then upload the data to the interface through the communication protocol,finally integrated the hardware and software of the system into the entire monitoring platform.Based on the theory of the multi-point monitoring model,we established the multi-point monitoring model of the system,in order to meet the performance requirements of the system model,the model is solved by LINGO software.Then we used the principal component analysis to optimize the model,and obtain the optimal layout model of the sensor.Through the instantaneous leakage diffusion model,simulated the concentration distribution curve in the lateral wind direction.Then the concentration distribution curve of the down-wind direction was obtained by using the data of Safer trace simulation.Afterwards the concentration distribution curve and the formula of the arbitrary position were obtained by Gaussian curve fitting.Finally,by the optimal sensor layout model and the concentration calculation formula at any position we verified and determined the position of the leak point.By the study on the design of the LNG leakage monitoring system,the research of the multi-point monitoring model and the LNG leakage diffusion model,the location of leakage point can be accurately positioned,which has a certain significance for LNG leakage accident prevention and emergency rescue.