Ammonia decomposition process efficiency is a key parameter to ensure its utilization as hydrogen carrier. In addition to the decomposition reactor studies, the evaluation of the separation steps of the forming gas generated is essential to ensure the recovery of high-purity hydrogen. However, detailed modeling and simulation, along with comprehensive techno-economic and environmental analyses (TEA) of these separation processes, have not been extensively explored in the literature. In this work, a rigorous modeling and simulation of the H2 + N2 mixture separation process is conducted, followed by a techno-economic assessment using the GREENSCOPE multi-criteria analysis framework. Namely, two routes were selected: pressure swing adsorption (PSA) and the cryogenic process. The four bed PSA unit simulation was carried out using Aspen Adsorption. In the cryogenic process the mixture is submitted to high compression followed by isenthalpic expansion which allows cooling below -230°C. Simulation was developed in Aspen Plus, while Aspen EDR was used for the cryogenic multi-stream heat exchanger sizing. Economic analysis was performed following established methodology for chemical processes. Finally, a multicriteria assessment was performed employing the GREENSCOPE methodology. The results indicate that the PSA unit resulted in nearly 50% H2 recovery versus >99% in the cryogenic process. Additionally, the PSA process achieved a lower LCOH: 0,50 versus 0,72 (US$/kg). The multicriteria analysis has shown that the cryogenic process presents a better performance regarding H2 recovery and solid waste disposal. On the other hand, the PSA process succeeds in the remaining scores – energy, GWP and LCOH – as it doesn’t require utilities, thus reducing its operating expenses and associated emissions. The results of this work can support future studies on the conceptual design of ammonia decomposition processes by providing insights into the techno-economic and environmental performance of each separation technology.
