In this work, steam reforming of natural gas is investigated with an application to a small-scale hydrogen production unit of industrial interest, coupled to PEM fuel cells. We carried out a thermodynamic analysis to estimate the efficiency of this overall process, which consists of a reformer reactor and two water gas shift reactors. We compare two different configurations: physical (PSA) or chemical (PROX) removal of CO from syngas. We find a similar global efficiency for both processes, although the PSA version has a relatively better performance. (c) 2007 Elsevier Ltd. All rights reserved.