In this work, hydrogen was separated from CH4/H-2 gas mixtures via forming hydrate in water in oil emulsion. Aqueous phase is the aqueous solution of 3.0 wt% Span 20. Oil phase is the mixture of diesel and cyclopentane (CP) with a CP concentration of 50 volt Span 20 was used to disperse water or hydrate in diesel to form emulsion or hydrate slurry. CP was used to moderate the hydrate formation condition. Two H-2/CH4 feed gas mixtures, containing 68.0 mol% and 84.7 mol% of hydrogen respectively, were prepared. A series of experiments were performed with respect to two feed gas mixtures to investigate the influences of temperature, pressure, and water cut upon the separation efficiency. Our experimental results show that suitable low temperature (274.15 K or so), high pressure (5-6 MPa), and water cut around 20 vol% are favorable for H-2 separation. The highest separation factor of H-2/CH4 reaches 49. After a two-stage separation at 274.15 K, the concentration of H-2 in gas phase could be increased from 68 mol% to more than 92 mol% and nearly 90% of H-2 can be recovered in gas phase. (C) 2013 Elsevier B.V. All rights reserved.