(436g) Optimizing Energy Efficiency of Ammonia Production Via Electrochemical Reaction and Haber-Bosch Process

Ammonia (NH₃) synthesis is crucial to the production of fertilizers, and accounts for nearly 2% of total global energy consumption. Therefore, finding methods to produce ammonia employing only renewable energy and sustainable feedstocks is paramount. This project uses dynamic simulation to design a 100% renewable ammonia synthesis plant, using only air and water as raw materials. Energy is supplied from a solar source, which is supplemented with industrial batteries. The intermittent nature of solar energy production requires the development of a dynamic production profile for the plant.

In this work, an electrolytic cell powered by a time-varying solar source is employed for hydrogen production. Air is separated via a membrane to provide a nitrogen source, and then the Haber-Bosch reaction is used to produce the product. The degrees of freedom in this problem are the number of batteries purchased, as well as the dynamic production and charging schedules. To determine the optimal production profile, a mixed integer non-linear programing model is formulated and solved. Results demonstrate how varying levels of production and energy storage usage correspond to different levels of energy availability, and show the feasibility of completely sustainable ammonia production, using no raw materials other than water and nitrogen, and creating zero emissions.