Water gas shift (WGS) reaction enhanced by a membrane reactor technology has emerged as a high-efficiency alternative to conventional fixed-bed reactors in integrated gasification combined cycle (IGCC) plants for the electrical power generation with carbon dioxide capture. Herein, the WGS performance of a catalyst-free membrane reactor made of a CO2-permeable ceramic-carbonate dual-phase (CCDP) membrane for converting coal gasification syngas to H-2 with CO2 capture is studied using a one-dimensional and nonisothermal mathematical model coupled with a CO2 permeation equation. The catalyst-free CCDP membrane reactor offers significantly enhanced WGS performance at high reaction pressures than a fixed-bed reactor. At 30 atm and 900 degrees C, WGS conducted in the single-stage, catalyst-free CCDP membrane reactor features a CO conversion >95%, a pure (100%) CO2 flow at the permeate side with ultrahigh CO2 capture ratio (>98%), and a retentate stream consisting of 100% recovered H-2 at a H-2 purity >90%. Due to a strong shift in thermodynamic equilibrium and the unique membrane characteristics, the CCDP membrane reactor achieves a superior performance in WGS, which will trigger innovation in catalytic membrane reactors and increase the competitiveness of a membrane reactor technology-based IGCC process with CO2 capture.