Efficient Zero-Carbon Ammonia Production

The Department of Energyĺs Industrial Decarbonation Roadmap aims to decarbonize energy- intensive sectors reaching net zero carbon emissions nationwide by 2050. The chemical industry sector accounts for 20% of CO2 emissions where new innovations in chemical manufacturing can help mitigate CO2 emissions. One chemical whose manufacturing contributes a substantial emission of CO2 at 1.8% of global CO2 emissions is ammonia, commonly produced from feedstocks of coal, oil, and natural gas. Toward attaining a net-zero carbon process for producing ammonia, concepts have been proposed using renewable solar or wind energy to operate water electrolyzers feeding hydrogen to the Haber-Bosch reactors. However, with low 10-15% equilibrium conversions, this approach meets net-zero carbon targets but inefficiently produces ammonia requiring larger and costlier plants to meet ammonia demand. A Phase I program developed an electrochemical synthesis method that produces ammonia from water and air. When powered by renewable energy, this ammonia generator produces green ammonia which will be conducted on-site in agricultural environments producing fertilizer for farmers. The Phase I project showed new catalyst designs applied to a novel reactor that helps form ammonia. The Phase II project will optimize this electrochemical ammonia reactor and package it into a refrigerator size unit that operates with intermittent renewable energy sources forming ammonia over time for use as a fertilizer. The main benefit of this compact ammonia fertilizer generator is that it can operate autonomously with renewable energy forming both green ammonia and hydrogen for energy storage. Hydrogen can be used as a fuel directly on farms replacing common practices of combusting propane further mitigating carbon dioxide emissions.