ESTABLISHED TECHNOLOGIES AND OPTIONS
Ammonia is mainly produced at commercial scale using the HB process, with technologies being developed to optimize it. This process produces ammonia from atmospheric nitrogen (N2) and H2
using a metal catalyst at high temperature and pressure. Traditionally, H2
is extracted from fossil fuels, as explained above.
The HB process is well established. It consumes 8 MWh of energy per tonne of ammonia produced, with the natural gas reforming process for H2 production (where applicable), and accounts for ~75% of total energy demand. The remaining 25% is needed during ammonia synthesis, gas compression and ammonia separation. The H2 generation process accounts for 90% of CO2 emissions involved in the HB process, which, over the course of its evolution, has been subject to development and optimization that have increased its efficiency.
Recent trends show that producing green hydrogen for all energy requirements is the only viable way to achieve deep decarbonization. The process uses water electrolysis and, ideally, renewable electrical sources to prevent the emissions generated by the SMR process.
Another step to improve efficiency is by using water electrolysis technology based on solid oxide cells (SOC), recovering the heat released from the synthesis reaction to perform steam-based electrolysis.
Alternative approaches to the HB process include electrochemical ammonia production and non-thermal plasma synthesis. These are promising technologies, but still need to reach commercially viable applicability.