Boil-off gas emission from the fuel tank of a LNG powered truck

LNG fueled vehicles are growing in many countries as a convenient solution for heavy duty and collective passenger transport due to the development of a capillary refueling infrastructure. Due to the known pressure build-up phenomenon, long duration parking of vehicles could cause flammable gas emission and potential explosive atmospheres in closed environments like repair workshops. In this paper, a model of pressure build-up and discharge is applied to small LNG tanks to evaluate the consistency of the phenomenon when pure methane is taken as reference for the calculation rather than the natural gas mixture. Moreover, it is compared with flow and pressure measurements performed for the first time, through a specifically developed suitable test facility. The scope of this study is to improve the awareness about the flammable gas emission from LNG fueled trucks in the safety framework. The expected results can be used to design ventilation systems to lower the flammable gas concentration and mitigate the explosion risk in closed environments.