Ammonia decomposition offers a scalable pathway for hydrogen production, combining efficient energy transport with low greenhouse gas (GHG) emissions. This study utilizes reactor modeling and techno-economic analysis (TEA) to evaluate ammonia decomposition technologies. High-temperature nickel-based reactors (650–950°C) and low-temperature ruthenium-based reactors (350–500°C) are modeled and analyzed with rigorous reactor models that account for heat and mass transfer limitations, enabling optimization of fuel consumption and process efficiency. Nickel catalysts achieve >90% conversion efficiency but require substantial high-quality heat input (e.g., combustion of H₂ or natural gas), resulting in significant energy penalties. In contrast, ruthenium-based systems achieve comparable conversion at lower temperatures, reducing thermal energy demand and enabling self-fueling through ammonia (thereby eliminating methane combustion), which improves energy efficiency and reduces direct GHG emissions. However, system economics are significantly affected by the elevated cost of ruthenium.
In addition to the energy demand of the cracking reaction, separating H₂ from the by-product N₂ incurs substantial energy input and presents a major opportunity for optimization. Two separation options—cryogenic separation (CS) and pressure swing adsorption (PSA)—are modeled with the reactor in an integrated process simulation, allowing evaluation and comparison of economic and emissions impacts for the pathways. Additionally, various fuel options, including natural gas, ammonia itself, are evaluated for their influence on process efficiency and emissions.
Using these modeling results, the economics and GHG emissions of ammonia cracking processes are evaluated across different catalytic technologies, separation methods, and fuel sources. This study informs stakeholdersabout the economic viability and GHG emissions impact of ammonia cracking, providing insights to advance scalable, low-carbon hydrogen production and support the industrial energy transition.
