Technical comparative study between dimethyl ether and liquefied natural gas production from natural gas

Abstract

The demand for energy has increased significantly. On the other hand, energy production suppliers are located in different and remote locations around the world. This requires efficient transport and storage of large-scale energy. Usually, large-scale is stored and transported in liquefied forms due to its reduced volume. However, liquid cryogenic storage loses some of its energy due to evaporation, called boil-off gas (BOG), which is called by change in temperature between storage medium and environment. This study examines the production of Dimethyl Ether (DME) and Liquefied Natural Gas (LNG) from natural gas, comparing boil-off gas (BOG) generation, energy intensities, and environmental impacts using dynamic simulation. Results from the simulation indicate a significantly higher BOG rate for LNG, with storage pressure increasing from 0.5 atm to 4.1 atm over 15 days, compared to a minimal increase from 23.4 atm to 23.7 atm for DME in the same period. This suggests that DME offers superior storage stability with lower evaporative losses. However, DME production was found to be more energy-intensive, with an energy consumption of 37.9 GJ/tonne compared to 2.07 GJ/tonne for LNG, and also generated higher CO2 emissions, at 2.12 kg CO2/kg of DME versus LNG emission of 1.16 kg CO2/kg of LNG. These findings highlight a trade-off between the lower BOG rate of DME and its higher energy and environmental impacts. Thus, the choice between DME and LNG production pathways depends on the specific priorities of the application, whether it be minimizing evaporative losses or reducing energy consumption and emissions.