We present here a study of the water gas shift membrane reactor (WGS-MR) in the context of its potential application in the IGCC process for power generation from coal. In our research, we use in the WGS-MR a sour-shift WGS catalyst and carbon molecular sieve (CMS) membranes, and show that the reactor displays higher conversions than a conventional packed-bed reactor (PBR) under the IGCC-relevant conditions, i.e., for temperatures up to 300 degrees C and pressures up to 25 bar. Our experimental results manifest the ability of the WGS-MR to operate under the desired conditions and to improve the efficiency of the WGS reaction. They demonstrate, in addition, the potential of the MR to carry out the in-situ separation of hydrogen using the CMS membranes. We conclude from our study, that the CMS-membrane-based WGS-MR is a good candidate technology for incorporation into IGCC power plants for environmentally-benign power generation.