(435a) Boosting Ammonia Synthesis in NH3-Sieving Inorganic Membrane Reactor

Ammonia is one of the most important and widely produced chemicals worldwide, and a primary ingredient for fertilizer and hydrogen carrier for energy supplying. Currently, owing to the kinetic and thermodynamic restrictions of ammonia synthesis reaction, most of ammonia is produced under conditions of temperature up to 400-500 ^oC and pressure up to 100-200 bar (Haber-Bosch process), resulting to intensive energy input and accounting for 3% of global energy consumption annually. Although numerous NH₃ synthesis catalysts with high activity has been developed recently, but the yield of NH₃ is still low. Membrane reactor which can timely and exclusively remove trace amount of NH₃ in abundant H₂/N₂ gas mixture at high temperature and pressure will overcome the thermodynamic restriction and achieve higher NH₃ yield, thus, making ammonia synthesis less energy intensive and more affordable. But, it is very difficult to find such a membrane material due to the harsh conditions and small size difference between H₂ (0.289 nm) and NH₃ (0.26 nm). In this study, we successfully introduce a new type of inorganic membrane which shows NH₃-selective/sieving effect. After investigating the NH₃/H₂/N₂ separation performance in detail, NH₃ synthesis within membrane reactor was also performed.