An efficient process for sustainable and scalable hydrogen production from green ammonia

Abstract

This study comprehensively investigates hydrogen production from green ammonia reforming, including synthesis of catalysts, reactor development, process integration, and techno-economic analysis. In-house developed Ru/La-Al2O3 pellet catalyst having perovskite structure showed high catalytic activity of 2827 h(-1) at 450 degrees C and stability over 6700 h at 550 degrees C, exceeding the performance of the majority of powder catalysts reported in the literature. A scalable 12-faceted reactor adopting the as-produced catalyst was designed to enhance heat transfer, producing over 66 L min(-1) of hydrogen with state-of-the-art ammonia reforming efficiency of 83.6 %. Near-zero CO2 emission of hydrogen extraction from green ammonia was demonstrated by-product gas recirculation as a combustion heat source. A techno-economic assessment was conducted for system scales from 10 kW to 10 MW, demonstrating the effect of reduced minimum hydrogen selling prices from 7.03 USD kg(-1) at small modular scales to 3.98 USD kg(-1) at larger industrial scales. Sensitivity analyses indicate that hydrogen selling prices may reduce even further (up to 50 %). The suggested hydrogen production route from green NH3 demonstrates superior CO2 reduction ranging from 78 % to 95 % in kg CO2 (kg H-2)(-1) compared to biomass gasification and steam methane reforming. These findings can be used as a basis for following economic and policy studies to further validate the effectiveness of the suggested system and process for H-2 production from NH3.