Novel Supports and Materials for Oxygen Separation and Supply

Existing coal gasification and combustion processes employ air as the oxidant, which leads to nitrogen oxide formation and dilute product/waste streams that are difficult and expensive to separate. This project will develop a more economical, non-cryogenic, and non-membrane means for separating, storing, and releasing pure oxygen for use in coal gasification and oxycombustion. Not only will nitrogen oxides be eliminated, but also product/waste streams will be more concentrated and easier to separate. The technology is based on the application of mixed metal oxide materials on novel supports capable of separating oxygen from air. The materials will possess large surface area, large oxygen storage capacity, and long term stability, and will not contain costly noble metals. In Phase I, a number of mixed metal oxide materials with large oxygen storage capacities were identified and shown to be capable of releasing large amounts of stored oxygen under ambient pressures and moderate temperatures. When supported on sintered metal fiber filters, these materials demonstrated improved oxygen production at lower temperatures. The ability to coat the supports with various ceramics and glass, in order to improve surface area, was demonstrated, and the coatings were shown to be stable up to 700oC. Phase II will involve optimizing the materials and coating process. Kinetic data will be obtained for the uptake and release of oxygen from preferred materials. Using the kinetic data, as well as other information, a bread-board reactor will be designed, fabricated, and tested. Commercial Applications and Other Benefits as described by the awardee: The cryogenic separation of oxygen is extremely expensive and remains the main obstacle to the commercialization of more environmentally-friendly fossil fuel processes (coal gasification, oxycombustion). By utilizing pure oxygen instead of air in these processes, a much more concentrated, easily separated carbon dioxide gas stream can be produced and NOx emissions can be eliminated.