We show from molecular dynamics insights that the nanoporous graphene (NPG) is an efficient membrane in hydrogen purification for separating gaseous H-2/CH4 mixtures with a high permeance and selectivity. The H-2 permeance is as high as 106 GPU, extremely higher than those of polymer membranes; the selectivity of H-2 over CH4 is up to 225, in the same order with those of polymer membranes. An economic analysis is performed from the aspects of compression energy consumption and required membrane area; it is shown that the NPG membrane requires less membrane area but a bit more compression energy compared with the polymer membranes. However, the slightly higher compression energy consumption can be totally offset by the remarkably smaller membrane area. In summary, the NPG membranes for hydrogen purification present an excellent separation performance with a high H-2 permeance, ultimately resulting in an impressive economic index comparing to the polymer membranes. (C) 2019 Elsevier Ltd. All rights reserved.