Investigating the Effects of Boil-off Gas on Liquefied Energy Carriers During Land Storage and Ocean Transportation

Abstract

As the largest energy production suppliers are in different locations of the world and the demand for energy increases significantly, storage and transportation of large-scale energy with high storage and transportation efficiencies are desired. Large-scale energy is stored and shipped in liquefied forms due to reduction in volume however storage medium in a liquid form with low boiling temperature loses some of its energy because of evaporation, called boil-off gas (BOG), which is caused by a change in temperature between the storage medium and the ambient. Therefore, this study presents sensitivity analysis for three types of energy carriers: liquefied natural gas (LNG), dimethyl-ether (DME), and methanol to store and transport energy in liquid form from an exporting country to an importing country. A calculation method is used to determine the daily BOG rates accounting for storage and transporting for the three liquefied energy carriers. A sensitivity analysis is presented to reveal the effects of changes in duration of land storage and ocean transportation on the total stored and transported masses. LNG has lost 7% of its mass as BOG after 60 day of shipping and this lost percentage is the highest compared to DME and methanol. Due to low mass loses during storage and transportation phases, methanol and DME are potential alternatives for storage and transportation of large energy quantities.