(425g) Modeling Helium Extraction and Liquefaction from Natural Gas

Helium, a critical yet limited rare resource, is present in trace amounts in LNG boil-off gas (BOG) and can be efficiently recovered through advanced cryogenic processes. Previous studies have focused on helium extraction from natural gas and LNG production, but limited research addresses its recovery directly from BOG. This study builds upon our previous LNG liquefaction research, proposing an industrial complex where LNG production, LNG storage, nitrogen rejection unit (NRU), and helium liquefaction subsystems are well integrated. Generally, the helium contained in the BOG stream from the LNG storage subsystem will be separated and purified in the NRU subsystem, where a nitrogen refrigeration cycle and a helium refrigeration cycle support the separation. After that, the recovered helium vapor will undergo multi-stage compressions, cooling, and expansion to finally be liquefied. The simulation results indicate that the BOG stream contains approximately 1.12% helium by mass, which, after processing through the NRU, yields a helium-rich stream with 99.96% purity. The entire industrial complex has been modeled and simulated with optimal considerations to minimize energy consumption. Meanwhile, the economic analysis has also been performed. The study provides deep insights into helium recovery and liquefaction from LNG production, making LNG production infrastructure a more viable resource for future sustainable helium production.