Sustainable design and analysis for helium extraction from sale gas in liquefied natural gas production

Currently, natural gas (NG) is an economically proven source of helium with up to 8 mol% concentration. Helium extraction at earlier stages in the natural gas liquefaction plant shows a motivating initiative to improve the economics and environmental aspects. Cryogenic fractionation is the most industrially used technology to recover helium from natural gas compared to other available technologies such as adsorption and membrane. In this work, three cryogenic-based fractionation processes, namely cold box, single column, and double columns, are assessed from technical, economic, and environmental perspectives. Aspen HYSYS simulation package is utilized to develop 1400 MMSCFD NG liquefaction capacity models for different helium concentrations. Cold box technology indicates the highest net profit per kg of helium recovery approximated at $260 for the case of a 10% ratio of sales gas vs. 90% LNG with a 1% initial helium concentration scenario. However, single column and double column technologies report the highest reduction in energy and emissions when integrating helium recovery and NG liquefaction with a 86% reduction for the same scenario.