부산대학교 도서관

Membrane-mediated gas separation has aroused substantial interest in He recovery from natural gas, while process simulation and optimization are frequently challenged by the rather low He concentration in most natural gas resources. Herein, we report the process design and techno-economic analysis using Aspen HYSYS V.14 to assess the potential of a two-stage membrane process for He recovery from low-grade natural gas pipelines containing 0.05–0.7% He with a target purity of 90% and a recovery rate of 95%. Two polypyrrolones with either high He permeance or high He-related selectivities are employed as the membrane materials, and the techno-economics of a two-stage membrane process is evaluated by the net present value and the specific He breakeven price with different membrane configurations according to the optimal membrane area and energy consumption under different He concentrations. It is proven that exploiting a high permeance membrane in the initial stage and a high selectivity membrane in the second stage leads to the lowest specific He breakeven price, and the membrane process is economically competitive when the He concentration is ≥0.1% in the feed. The annualized cost analysis reveals that the membrane process is dominated by compressor power consumption and membrane-related costs. The sensitivity analysis demonstrates that developing high-performance and low-cost membrane materials is necessary to reduce the breakeven price of recovering He from natural gas with extremely low He content. The low energy consumption and absence of waste emission render the membrane process with outstanding operational capability for sustainable He recovery.