Novel hollow fiber membrane reactor for high purity H₂ generation from thermal catalytic NH₃ decomposition

Although storage of H₂ in various liquid chemicals makes it very attractive for practical applications, production and purification of H₂ from decomposition of these chemicals under relatively mild conditions is still challenging. In this work, we reported production of high-purity H₂ from NH₃ decomposition using a combined packed bed/membrane reactor loaded with Ru-based catalyst. Three types of membranes (modified MFI zeolite membrane, carbon molecular sieve membrane, and Pd/Ag membrane) were employed and compared for H₂ production and purification from NH₃ decomposition. All these membrane reactors exhibited high NH₃ conversion of >99% with H₂ recovery of >90% under pressurized NH₃ feed of 7 bar. Nevertheless, H₂ purity varied because of the different separation performance of these membranes. High H₂ purity of >99.999% with <10 ppb NH₃ concentration in permeate was achieved using high-quality Pd/Ag membrane reactor. These results suggest a feasible and highly energy efficient option for producing high-purity H₂ from NH₃ decomposition.