image: (a) Working principle for conventional and EMF-assisted H-B strategies. (b) The technological flow diagram of EMF-assisted ammonia synthesis. (c) Digital photograph of the EMF reactor. (d) Digital photograph of a quartz tube filled with 80 g Fe-based catalyst for the scale-up experiment. (e) Infrared thermal imaging of the reaction zone with external heating of 200 ℃. view more
Credit: ©Science China Press
Ammonia (NH3), as one of the most common industrial chemicals, is essential for nitrogenous fertilizer production and shows potential as a next-generation green fuel. Industrial ammonia synthesis relies on the reaction of fossil fuel-derived hydrogen and nitrogen (Haber-Bosch method) under high temperature (~500 °C) and high pressure (>15 MPa), which consumes ∼2% of global power and discharges ∼1.5% of global greenhouse gas.
The team from Tianjin University in China developed an electromagnetic field (EMF)-assisted H-B technique for ammonia synthesis under mild conditions by adopting commercial iron-based catalysts. The onset temperature with EMF assistance is 100 °C, which is obviously lower than that without EMF assistance (300 °C). In a typical scale-up experiment with 80 g commercial catalysts, the EMF-assisted H-B technique obviously increases the ammonia yield (~5 times) and decreases the energy consumption (~2.7 times). The enhanced catalytic performance can be ascribed to the EMF inducing more electron transfer from Fe orbitals to N≡N orbitals in both side-on and end-on adsorption modes.
They constructed a pilot-scale system with a production capacity of 10,000 kg per year for EMF-assisted thermal catalysis at Tianjin University, taking the first step in the development of EMF-assisted thermal catalysis for industrialization from the laboratory. They are carrying out further scale-up research on EMF-assisted thermal catalysis in Qinghai Province, which is rich in renewable energy, to explore a feasible industrial path for the breakthrough of large-scale storage and transportation bottlenecks of renewable energy to promote the early realization of the "dual carbon" goal.
https://doi.org/10.1016/j.scib.2023.07.037
Journal
Science Bulletin