Comparative techno-economic and life cycle greenhouse gas assessment of ammonia production from thermal decomposition of methane and steam methane reforming technologies

Abstract

This study assesses the life cycle greenhouse gas (GHG) and economic feasibility of applying thermal decomposition of methane (TDM) technology for ammonia production compared to the conventional steam methane reforming (SMR) technology. A detailed process model for each ammonia-based technology was developed to get data to perform energy, life cycle GHG emissions, and economic analyses. The results showed that the SMR plant consumes 30.3% more fuel than the TDM. The life cycle GHG emissions of TDM and SMR are 1.42 and 2.51 t CO2e/t NH3, respectively. The combustion and process emissions released to the environment and electricity emissions take a large share in the life cycle emissions of SMR and TDM, respectively. The production cost of ammonia from SMR is lower than TDM by $69/t NH3. TDM requires a higher investment because of high capital costs and the huge amount of natural gas needed as feedstock. For TDM, the sale of the oxygen product does not provide sufficient revenue to outperform SMR. However, integrating a carbon capture unit into TDM makes it economic performance better than SMR (with a carbon capture unit) when the sale of oxygen is considered. The results also showed that SMR (without carbon capture unit) is more economically attractive when the carbon price benchmark is below $99/t CO2. Above this carbon price, integrating a carbon capture unit into TDM is economically preferable.