H-2 yield and purity from sorption enhanced steam reforming (SE-SR) are determined by temperature, S:C ratio in use, and feed gas composition in hydrocarbons, N-2 and CO2. Gases with high hydrocarbons composition had the highest H-2 yield and purity. The magnitude of sorption enhancement effects compared to conventional steam reforming (C-SR), i.e. increases in H-2 yield and purity, and drop in CH4 yield were remarkably insensitive to alkane (C1-C3) and CO2 content (0.1-10 vol%), with only N-2 content (0.4-70 vol%) having a minor effect. Although the presence of inert (N-2) decreases the partial pressure of the reactants which is beneficial in steam reforming, high inert contents increase the energetic cost of operating the reforming plants. The aim of the study is to investigate and demonstrate the effect of actual shale gas composition in the SE-SR process, with varied hydrocarbon fractions, CO2 and N-2 in the feedstock. (C) 2017 The Authors. Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.