Process implications of electrifying ammonia production

Current ammonia production, based on Steam Methane Reforming (SMR) coupled to the Haber–Bosch (HB) process, is responsible for about 1.2% of global CO2 emissions. Therefore,also the NH3 industry is considering a full or partial electrification, for example, by replacing SMR-based with electrolytic H2 production. This paper critically considers the implications of such a shift for two alternative scenarios, namely combining HB with either low- or high-temperature electrolysis. Regarding emissions, electrification can indeed be beneficial with a cut of up to 96–99%, but only when using 100% renewable electricity rather than coupling to the currently still mainly fossil-driven grid. Also, energy efficiency can be improved, thanks to the availability of high-purity electrolytic hydrogen and electrical rather than steam-based compressors. However, due to the higher intrinsic energy demand of electrolytic H2, the total energy consumption (in GJ/t NH3) for both alternative scenarios exceeds that of the conventional process.