Perovskite/Oxide Composites as Mixed Protonic/Electronic Conductors for Hydrogen Recovery in IGCC Systems

70103 Integrated Gasification Combined Cycle (IGCC) systems are promising new alternatives for highly efficient and environmentally friendly power generation. In order to make these systems commercially viable, a portion of the hydrogen in syngas needs to be recovered as a value-added byproduct through the use of hydrogen separation membranes such as proton-conducting membranes. Since current membrane technologies for hydrogen separation are incompatible with the high-temperature, high-pressure environment in IGCC systems, robust and efficient membrane systems are required. This project will develop a novel, dense, ceramic-composite membrane that will function as a mixed protonic/electronic conductor under expected IGCC operating conditions. These mixed-conducting composite membranes will allow pressure-driven hydrogen separation at 800-900¿C, and at higher flux-rates than possible with single phase membranes, thus resulting in a very-high-purity hydrogen stream. In Phase I, the feasibility of the process for forming mixed conducting protonic/electronic conductors was demonstrated. It was determined that a flux of over 9 cc/cm2/min through a 15 cm membrane can be achieved. Additionally, it was demonstrated that the new materials have increased thermochemcial stability in CO2-containing atmospheres, compared to materials in conventional proton conductors. In Phase II, a single-wafer module will be built and tested to demonstrate the hydrogen flux necessary for commercial feasibility. Commercial Applications and Other Benefits as described by awardee: The hydrogen separation membrane should have a major impact on the commercial feasibility of IGCC systems and other industrial hydrogen recovery/separation processes. Further, this membrane should be applicable to such emerging technologies as intermediate-temperature fuel cells based on proton-conducting electrolytes.