(730d) Dense Metallic Membrane Reactor Synthesis of Ammonia at Moderate Conditions and Low Cost
- Conference: AIChE Annual Meeting
- Year: 2017
- Proceeding: 2017 AIChE Annual Meeting
- Group: Topical Conference: NH3 Energy+ - Enabling Optimized, Sustainable Energy and Agriculture
Thursday, November 2, 2017 - 1:24pm-1:42pm
Dense metallic membranes are known to offer a unique mechanism for hydrogenation reactors by providing permeating atomic hydrogen for the preferential partial hydrogenation of some hydrocarbons. Yet, this concept for ammonia synthesis has not fully been explored. With additional motivation from electrochemical cells and recent DFT studies on the possible metal catalysts, a new concept for ammonia synthesis has been developed using a hydrogen permeable membrane made from cost effective group V metals. This base metal membrane is coupled with asymmetric catalyst coatings to allow hydrogen permeation and nitrogen dissociation on respective membrane surfaces. The combination of the modified nitrogen dissociation surface catalyst and the highly reactive permeating hydrogen allows ammonia to be formed at low pressures and moderate temperatures. Using this concept, we have measured NH3 synthesis rates as high as 6 × 10-9 mol cm-2 s-1 in preliminary experiments at 500 °C and 0.8 bar. These rates are competitive with analogous experiments using ceramic proton conducting membranes. Performance and stability will be discussed with various catalyst and hydrogen permeating base metal combinations to understand the full potential of this ambient pressure ammonia synthesis method.