Green impacts of transforming green electricity into microwave for ammonia and urea production

Green NH3 production is challenged by high energy consumption, costs, and low yields. Here, we proposed a new green NH3 process utilizing microwave (MW)-driven N-2 transformations (GreenE+MW). This process integrates water electrolysis, air separation, MW-assisted NH3 synthesis, and NH3 separation. For comparison, a green NH3 process using the Haber-Bosch technology (GreenE+HB) was established, and the energy, economic, and environmental impacts were evaluated. The GreenE+MW process increased NH3 yield by 25.14% and reduced energy consumption by 20.69% compared to the GreenE+HB process. Furthermore, it demonstrated notable advantages in cost and carbon footprint, with green NH3 production costs potentially reduced to 326.84 USD/tNH(3) at electricity price of 0.02 USD/kWh. Based on which, a green urea process was proposed, achieving an 85% reduction in carbon emissions (0.128 kgCO(2)e/kgUrea) compared to conventional methods. This work offers a unique electrification technology to reconstruct the industrial NH3 and urea production processes with a lower carbon footprint.