Circular Economy Analysis of Helium Recovery from Sales Gas Product

Abstract

The helium presence in natural gas (NG) is usually low, thus it seems infeasible economically to recover it. However, the continuous increase in helium demand with a growing rate of about 5%, industrial projects are searching for economic approaches to recover helium from sales gas at the earlier stages of the liquefaction process. This work investigates the techno-economic and environmental benefits of recovering helium from sale gas product. Among the available recovery technologies, namely, cryogenic fraction, adsorption-based processes, and membrane-based processes, the cryogenic fractionation is considered for analysis due to its wide use in industry. The cryogenic fractionation represented by three different configurations; single column, double columns fractionation, and cold box are developed using Aspen HYSYS to perform the steady-state simulation with a basis of 1400 MMSCFD of natural gas. Aspen Process Economic Analyzer and Aspen Energy Analyzer, are then used to carry out the economic evaluation and utility optimization steps. The results for all alternatives are compared in terms of helium recovery, emissions reduction, energy savings, and economic profitability. An illustrative case study is presented for the assessment of helium recovery for different helium molar composition in the NG feedstock and various helium selling prices. The results demonstrate cold box as the optimal technology for 3.5 vol% helium recovery with approximately $25.4 per kg of helium produced (PHP) compared to approximately $24.2 and $24.3 PHP for double column and single column options, respectively. Moreover, higher concentration of helium at around 7% indicates a profitability profile with lower overall net economic value of approximately $11.7 PHP for cold box alternative. The results for all options indicate high purity for helium with more than 98% and a recovery of more than 99%.