Techno-Economic and Environmental Assessment of Hydrogen Production from Ammonia Cracking in Modified Methane Reactor

This paper evaluates the technical performance, economics, and cradle-to-gate environmental impacts of producing hydrogen by cracking ammonia in a,modified steam-methane reformer (SMR). Top-fired SMR furnace was retrofitted into an ammonia cracker using a non-noble Ba–Co–Ce catalyst (98% conversion), followed by thermal-swing adsorption (TSA) for NH₃ removal and pressure-swing adsorption (PSA) for H₂/N₂ separation. The modified unit delivers 7,000 Nm³ h⁻¹ of 99.99% H₂ at 70% recovery. A detailed energy balance, including pumping, evaporation, preheating, cracking, cooling, vacuum, and recompression, yields an overall process efficiency of 58%. The levelized cost of hydrogen (LCOH) falls with increasing gas hourly space velocity (GHSV): $ 5.75 to 4.74 kg⁻¹ across 25–1000 kmol h⁻¹; the current operating case yields $ 4.84 kg⁻¹. Scenario analysis reveals an LCOH of $ 5.50 kg⁻¹ with grid-mix electricity versus $ 5.34 kg⁻¹ using photovoltaic (PV) power for electric loads. Life-cycle assessment indicates that upstream ammonia production and electricity usage dominate impacts: total Global Warming Potential (GWP) is 19.51 kg CO₂-eq kg⁻¹ H₂ (grid) and 14.83 kg CO₂-eq kg⁻¹ H₂ (PV), with a 24% reduction. The obtained results demonstrate that retrofitting SMRs for ammonia cracking is technically feasible and near-term deployable; meaningful decarbonization, however, hinges on cleaner electricity and a low-carbon ammonia supply.