Start Date
4-1969 8:00 AM
Description
This paper discusses a new process for converting atmospheric nitrogen into nitric acid and nitric oxides based on technology and information developed by our aerospace programs. The basis of this process is the high temperature reaction of air to form appreciable percentages of nitric oxide. Nitric oxide is thermodynamically unstable at lower temperatures and the initial equilibrium must be frozen in a few milliseconds as the air temperature is decreased to a region of slow kinetics.
In this process, compressed air is heated in an electric arc to 3000 - 4000°K. Then it is immediately cooled very fast in a magnetohydrodynamic power conversion unit to about 2000°K and the generated electricity is recycled to the arc heaters. The nitric oxide (NO) formed in the arc is cooled further rapidly in a water spray to about 1400 K. This makes possible a recoverable concentration of 5.0 to 9.0% NO in air for this process. Finally, the nitric oxide reacts with more oxygen to form nitrogen dioxide which is converted to nitric acid by absorption in water.
Although some of the thermodynamics and kinetics for this process have been known for years, accurate quantitative determination of the equilibrium and reaction rate values was not done until the aerospace programs in reentry sciences and atomic physics were carried out in the last few years. Engineering and applied science data for this process are required for electric arc heaters, gas heat transfer, gas dynamics, and high temperature materials, and this has been obtained in various aerospace programs.
Process for Thermal Fixation of Atmospheric Nitrogen
This paper discusses a new process for converting atmospheric nitrogen into nitric acid and nitric oxides based on technology and information developed by our aerospace programs. The basis of this process is the high temperature reaction of air to form appreciable percentages of nitric oxide. Nitric oxide is thermodynamically unstable at lower temperatures and the initial equilibrium must be frozen in a few milliseconds as the air temperature is decreased to a region of slow kinetics.
In this process, compressed air is heated in an electric arc to 3000 - 4000°K. Then it is immediately cooled very fast in a magnetohydrodynamic power conversion unit to about 2000°K and the generated electricity is recycled to the arc heaters. The nitric oxide (NO) formed in the arc is cooled further rapidly in a water spray to about 1400 K. This makes possible a recoverable concentration of 5.0 to 9.0% NO in air for this process. Finally, the nitric oxide reacts with more oxygen to form nitrogen dioxide which is converted to nitric acid by absorption in water.
Although some of the thermodynamics and kinetics for this process have been known for years, accurate quantitative determination of the equilibrium and reaction rate values was not done until the aerospace programs in reentry sciences and atomic physics were carried out in the last few years. Engineering and applied science data for this process are required for electric arc heaters, gas heat transfer, gas dynamics, and high temperature materials, and this has been obtained in various aerospace programs.
Comments
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