Preliminary economics for green ammonia synthesis via lithium mediated pathway

High energy density liquid fuel, ammonia, faces increasing interest globally as a carbon-free energy carrier that can be transported over long distances for decentralized and remote distribution. The dominant ammonia production method, Haber-Bosch, is both energy and carbon intensive to overcome the slow kinetics of the ammonia synthesis reaction from nitrogen and hydrogen. An early techno-economic model for lithium mediated electrochemical ammonia synthesis at mild process conditions using feed rates of 27 metric ton/day for lithium hydroxide, 127 metric ton/day for cryogenic nitrogen and 264 metric ton/day electrolysis grade water is presented. Further analysis was carried out to analyze the energy consumption and reduction per metric ton of ammonia in comparison to electrochemical ammonia using H+ conductive membrane and small-scale Haber-Bosch technology. Electrochemical ammonia synthesis using lithium-ion conductive membrane coupled with nitrogen generation by cryogenic distillation was found to be a sustainable pathway. The ammonia production cost via lithium mediated pathway was estimated to be less than $700 per metric ton and was found to be comparable with costs using traditional Haber Bosch. The environmental impact of electrochemical ammonia using the alkali group 1 metal, lithium, was also assessed from cradle to product.

Automated summary

Ammonia, a high energy density liquid fuel, is gaining global interest as a carbon-free energy carrier for long-distance transportation. The use of lithium-mediated electrochemical synthesis of ammonia is considered a sustainable pathway with lower costs and environmental impact compared to traditional methods.