Simulation of boil-off gas effect along LNG supply chain on quantity and quality of natural gas

Abstract

Liquefied natural gas (LNG) is the most economical way of transporting natural gas over long distances. During LNG transportation and storage at -163 °C, boil-off gas (BOG) losses are unavoidable, its effects on the quantity and quality of natural gas. The number of BOGs that are formed along the supply chain changes over time. This study aims to determine the amount of BOG formed and changes in gas quality such as the Wobbe Index, methane number and heating value along the supply chain and also to determine the effect of shipping distance. The method used is a dynamic simulation process using UniSim Design R390.1 software. The results show 2,966 m3 of BOG occurred in the LNG loading process, corresponding to 2.7% of total LNG carried. For the shipping process, 4,118 m3 (4%) of the remaining LNG turn into BOG and 2,545 m3 (2.63%) of the remaining LNG in the unloading process. Longer shipping time causes heating value, Wobbe Index to increase and reduce the methane number.