Techno-economic analysis of integrating methane pyrolysis and reforming technology for low-carbon ammonia

Industrial ammonia production, primarily achieved through steam methane reforming (SMR) technology significantly contributes to CO₂ emissions. To align with global climate goals and limit temperature rise below 1.5 °C, retrofitting existing plants becomes imperative. Methane pyrolysis (MP) emerges as a promising solution, enabling hydrogen or ammonia production without carbon dioxide emissions while yielding marketable solid carbon. This study investigates the technical and economic feasibility of integrating MP into a conventional SMR-ammonia plant by splitting the natural gas (NG) feed between the MP and SMR sections. Operating at 33 bar and 1,400 °C, the MP section achieves an impressive 71.2 % conversion rate, concurrently producing carbon black as a valuable co-product. Under the greenhouse gas (GHG) Scope 1 emission protocol, our integrated model shows reduced CO₂ emissions from 1.3 to 0.23 tons per ton of NH₃ produced, along with lower energy consumption compared to the conventional plant. Sensitivity analysis confirms the economic viability of the integrated model under various CO₂ tax and carbon black price scenarios. Considering current and projected Middle Eastern prices for NG, ammonia, carbon black, and a CO₂ tax, the 50 % integration scenario emerges as approximately 48 million USD more profitable annually than the baseline model. This enhanced profitability stems from additional revenue generated by carbon black sales and decreased CO₂ emissions. The levelized cost of ammonia from the proposed model stands at 187 USD/ton when accounting for carbon black revenue and 240 USD/ton without it.