A novel cost-effective silica membrane-based process for helium extraction from natural gas

Natural gas reserves with 0.3-2 mol% helium are considered as the only viable source for this noble gas. Currently, cryogenic separation is used to extract helium, but it is energy-intensive. While membrane-based separation is a promising alternative, it is still not considered economical. Even for an inorganic/silica membrane with relatively high selectivity and permeance, a multi-stage membrane system with inter-stage compression is required, which necessitates high CAPEX and OPEX. This study proposes a novel process to enhance the selectivity and permeance of an inorganic/silica membrane system to eliminate the costly inter-stage compression. A 16-24% reduction in the CAPEX and 23-57% in the OPEX are achievable for a natural gas feed with 3-5 mol% helium. In contrast, for a 2 mol% helium feed, the OPEX increases by 34%. However, a 30% decrease in the capital cost outweighs the OPEX increase to make the new process more profitable. (C) 2018 Elsevier Ltd. All rights reserved.