Research On Leakage Monitoring And Early Warning Technology Of Long Tube Trailer

Long tube trailer is a kind of mobile pressure vessel.It is a gas transportation equipment consisting of three parts: walking device,large volume seamless steel cylinder and connecting device.The long tube trailer is mainly used to store and transport compressed natural gas CNG.It is a flammable and explosive dangerous gas.When it is in the air concentration range of 5% to 15%,it can explode when it occurs in open fire.When the concentration is above 15%,it can burn normally.Long tube trailers usually run or park in main roads or residential areas of cities.Once the accidents such as leakage occur,the social harm and economic losses caused by long tube trailers can hardly be estimated.Therefore,effective measures must be taken to ensure the safe operation of long tube trailers.Based on the leakage monitoring and early warning of long tube trailers,a monitoring and early warning method of compressed natural gas leakage based on Fiber Bragg grating temperature sensor has been determined.1)The structure,gas cylinder and safety accessories of the long tube trailer are studied.Accident analysis of gas leakage may lead to the defects of the statistical model in the recent 6 years long tube trailer for regular inspection found,the leak is one of the main failure mode of long tube trailer,and the cylinder end plug and valve tube trailer is the main parts of the leakage may occur.2)The current situation of fiber Bragg grating sensing technology and the working principle of fiber Bragg grating temperature sensor are studied.The feasibility and reliability of leakage monitoring and early warning of long tube trailer based on Fiber Bragg grating sensing technology is verified.3)Fluent software is used to simulate the leakage and diffusion of compressed gases,and the path and mode of gas diffusion are obtained,and the distribution rule of gas components,temperature and flow rate is also obtained.It is found that the simulation results are consistent with the analysis results of regular trailers and gas leakage models,indicating that the simulation results are highly reliable.4)Through analyzing the leakage failure mode and Fluent leakage simulation results of long tube trailers,the layout location of fiber Bragg grating temperature sensor is determined and on-site installation is made.The leakage monitoring and early warning of long tube trailer is experimentally studied,and it is concluded that the most likely place to leak is the connection between the cylinder and the stopper near the outer side of the long tube trailer.