High Efficiency Low Cost Electrochemical Ammonia Production

Industrial processes for production of ammonia (NH3) and urea nitrogen-based fertilizers aremainly based on the Haber-Bosch process, which involves the heterogeneous reaction ofnitrogen (N2) and hydrogen (H2) on an iron-based catalyst at high pressure (150-300 atm) andhigh temperature (400 & deg;-500 & deg;C). The equilibrium conversion of H2 and N2 gas to NH3 in theHaber-Bosch process is generally only on the order of about 15%. Such low conversionefficiency gives rise to energy intensive, large scale chemical plants, with high CO2 emissions, atan installed cost of more than $1 billion per plant. More sustainable and economical productionmethods are required to support growing world demand. To specifically address this need,Proton Energy Systems, in collaboration with the Colorado School of Mines and the NationalInstitute of Standards and Technology (NIST), proposes development of an efficient solid stateelectrochemical process utilizing anion exchange membrane (AEM) technology, which can beoptimized for use with distributed renewable energy sources. The team has extensivecompetencies in cell design, tailoring of membrane and catalyst properties, and balance of plantdesign and integration, providing a strong foundation for the proposed work.A successful electrolytic ammonia process will enable establishing a new nitrogen fertilizerindustry based on networks of distributed-scale, near-point-of-use production plants. Thiselectrically driven process is able to achieve optimal efficiency soon after start-up, and iscompatible with intermittent operation. This feature enables utilization (and monetization) ofrenewable electricity without the need for transmission capacity expansion. To the extent thatrenewable electricity is utilized to drive the process, CO2 emissions will be eliminated from theproduction step, and further reduction of emissions will be realized through the reduced need forammonia transport. The proposed innovation will enhance soil productivity in developing partsof the world, and assure food security for domestic farmers by developing a low-cost andsustainable source of N-fertilizer. There is also a natural synergy in using distributed wind powerfor fertilizer production, as our best domestic wind resources are co-located with the highest useareas of ammonia-based fertilizers. In the Plains and Upper Midwest, excess wind productioncapacity, transmission limitations, and high regional demand for N-fertilizers combine to createexcellent economic drivers for this technology.