MAY 15, 2017 8:13 AM PDT

Making fertilizer from thin air

Ever since the Haber–Bosch process of artificial nitrogen fixation revolutionized the agricultural world, the race to continue developing more and more efficient fertilizers has been on. That race just picked up speed as farmers may soon be able to create fertilizers out of thin air.

Bhaskar S. Patil, from the Eindhoven University of Technology, has developed a reactor that coverts nitrogen from the atmosphere into NOx, the raw material for fertilizer. This strategy is potentially five times as efficient as current methods and could change the way small farmers run their farms.

Looking for alternative ways of producing ammonia and nitrogen oxides, Patil built two reactors: the Gliding Arc (GA) reactor and the Dielectric Barrier Discharge (DBD) reactor. The GA reactor proved to be most successful at producing nitrogen oxides. Science Daily explains: “In this reactor, under atmospheric pressure, a plasma-front (a kind of mini lightning bolt) glides between two diverging metal surfaces, starting with a small opening (2 mm) to a width of 5 centimeters. This expansion causes the plasma to cool to room temperature. During the trajectory of the 'lightning', the nitrogen (N2) and oxygen (O2) molecules react in the immediate vicinity of the lightning front to nitrogen oxides (NO and NO2).”

Patil was able to achieve an energy consumption level of 2.8 MJ/mole with the GA reactor. That is a step up from the other methods that use around 0.5 MJ/mole. “With the theoretical minimum of Patil's reactor, however, being that much lower (0.1 MJ/mole),” reports Phys, “…in the long term this plasma technique could be an energy-efficient alternative to the current energy-devouring ammonia and nitrate production.”

The most exciting aspect of Patil's method is that it does not need any raw materials and production can rely on renewable energies. His model is ideal for farms in rural regions that have little or no access to power grids.

This method is well suited for small rural farms. Photo: JAM Canada

Further research is still needed to make this method an industrial reality. Currently the German Evonik Industries, is continuing to enhance the reactor. The hope is that in addition to small farms, the technology could be utilized to improve growth of plants in greenhouses and to store sustainable energy in liquid fuels.

Furthermore, this breakthrough also comes as a positive light for reducing carbon dioxide emissions that spur climate change. Producing ammonia (NH3) and nitrogen oxide (NOx) requires a lot of energy and this process makes up about 2% of all global CO2 emissions. Changing our reliance on such high-energy processes to generate fertilizers would help curb our CO2 emissions worldwide.

Sources: Science Daily, Phys

About the Author
Bachelor's (BA/BS/Other)
Kathryn is a curious world-traveller interested in the intersection between nature, culture, history, and people. She has worked for environmental education non-profits and is a Spanish/English interpreter.
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