Development And Application Of Pressure Testing System For LNG Gas Cylinder Inner Liner

Since 2020,the proportion of liquefied natural gas(LNG)in the total energy consumption has been increasing.As a clean fossil energy,it has the advantages of low price,high safety,green environment and long mileage in the application of transportation.Especially under the influence of achieving carbon peak and carbon neutrality,the country has paid more attention to energy conservation and emission reduction,and implemented some policies such as "oil to gas" and "coal to gas" The application of taxis and heavy-duty trucks has achieved significant results,providing a reference for natural gas to replace traditional highly polluting fossil fuels in the field of transportation.Therefore,vehicle LNG cylinders have broad development prospects in the future.According to the design standards for LNG cylinders both domestically and internationally,pressure tests,also known as pressure tests,are required during the manufacturing and production process of LNG cylinders to test their reliability and safety.At present,scholars and enterprises at home and abroad have conducted a lot of research on the methods and system equipment for pressure testing of LNG cylinder liners.However,there are still problems in the actual production testing of cylinder liners,such as unreasonable testing methods,low testing efficiency,poor sealing effect,and difficulty in collecting and processing test data.In response to the current problems,this article conducts research on the accurate input of the pressure process,sealing effect,automatic control of the test,and multi station parallel testing in pressure testing.A multi station automatic pressure testing system for pressure testing of large volume LNG cylinder liners has been designed and developed.Firstly,based on the national standards and technical requirements for pressure testing,a comprehensive analysis was conducted on the testing methods and advantages and disadvantages of hydraulic and pneumatic tests.Combined with the characteristics of the cylinder liner,the testing method was determined.Determine the basic functions that the system needs to have based on the processing technology of the cylinder liner and the technical requirements for pressure testing,and complete the development of the entire system plan;We have optimized the energy consumption of the testing system,improved the system scheme,and designed the structure of the testing pipeline and cylinder liner support conveyor frame.Then,in response to the connection and sealing issues during the testing process,a quick plug-in compression fixture is designed,and its strength is verified and the sealing structure is optimized using finite element analysis.By analyzing the sealing principle and material characteristics of nitrile rubber O-rings,the influence of different influencing factors on the sealing performance of the compression fixture is studied,and the structural parameters are optimized;Then,an automatic control logic flow was designed for the voltage withstand test steps.Using VB.NET programming language,a Windows operating system based upper computer control software was developed to achieve automatic control of the voltage withstand test process,real-time monitoring of the voltage withstand test process,and collection and processing of test data.Finally,on-site installation and debugging of the entire testing system will be carried out.The system basically meets the design requirements of automatic control for withstand voltage testing,reduces testing time,improves production efficiency,records test data in detail,and can generate test reports for easy archiving and processing,bringing good economic benefits.