BOIL-OFF PREVENTION AND THERMAL MODELLING OF LNG FUELLING STATIONS

摘要

During Liquefied Natural Gas/Compressed Natural Gas from LNG (LNG/LCNG) station operation, boil-off gas (BoG) can be generated from different processes, like heat leak to the storage tank, cooling piping before fuelling, vapour return from LNG vehicles back to storage tank, evaporation of LNG, which was trapped in piping after fuelling process, etc. For modelling pressure dynamics in vacuum insulated storage tanks that are part of LNG fuelling stations, Heat-Management Program “Zero-loss” was developed. The program can be used for prediction of the pressure behaviour of the LNG storage tank that collects all the vapour inputs from operation of the station. The program can indicate optimal regimes of station operation, recommended frequency of vehicle fuelling, loading of the station, so that LNG venting is prevented or additional equipment for liquidation of BoG is not needed. Heat-Management Program “Zero-loss” gives possibility to fill input process data, the station construction and features, and obtain the result as a graph of pressure dynamics in time as a function of frequency of fuelling. If station works in operation mode, when pressure growth in storage tank is unavoidable due to low frequency of fuelling, several types of boil-off gas handling equipment can be applied for prevention of venting of gas and, consequently, loss of LNG.