(780b) Small-Scale Production of Ammonia From a Combined Reactor-Membrane-Adsorber

Ammonia is one of the world’s most important chemicals; over 130 million metric tons are produced annually.  Without modern fertilizers derived from ammonia two billion people would starve.  Ammonia is currently produced via the Haber-Bosch process in large capital-intensive factories.  Despite a century of optimization, single-pass ammonia production is only roughly 20% and requires large amounts of sacrificial fossil fuels to obtain raw materials.

We present work on a hybrid membrane/adsorption reactor system capable of producing ammonia from wind power.  Hydrogen and nitrogen are obtained from electrolysis of water and membrane separation of air, respectively.  The ammonia produced can be separated by either a selective membrane or pressure-swing adsorption.  We believe membrane separation is more effective for larger scale operation, but the simpler absorption is better for smaller scale.  By combining reaction and absorption into a single unit operation, ammonia conversion can be increased.  The system performs as a mixed-media membrane reactor without the potential physical limitations of a membrane structure.  Such a system may make sustainable distributed production of ammonia possible.