Green ammonia production via a catalytic membrane reactor: Proof of concept through experiments and simulations

Ammonia (NH₃) plays a vital role in fertilizer production, but an energy-saving NH₃ production process compared to the Haber–Bosch process is urgently being developed. A catalytic membrane reactor (CMR) that integrates the reaction with a Ru (10 wt%)/Cs/MgO catalyst and the membrane separation with a sulfonated (3-mercaptopropyl)trimethoxysilane (MPTMS) membrane in one unit was used for green NH₃ production at 300°C and 200–300 kPa. Consequently, the NH₃ mole fraction was greatly increased to 0.031–0.046 in the permeate side of the membrane, which is 10 times higher than 0.0028–0.0039 in a packed bed reactor, together with an improved conversion from ~0.5% to 6%–9%. Process simulation of the CMR was formulated, confirming that the simulated performance agreed with experiments. Process simulation and experimental results show that increasing the feed pressure and flow rate would decrease the NH₃ molar fraction in the permeate side of the membrane and conversion, since high pressures promote H₂ and N₂ permeation more than NH₃.