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Nitrogen Process
The Manufacturing Process
Steam
Steam and natural gas are combined at a three-to-one ratio. This mixture is preheated and passed through catalyst-filled tubes in the primary reformer.
Primary Reformer
Most of the natural gas is reformed to make hydrogen, carbon monoxide and carbon dioxide (H,CO,CO2). This mixture flows to the secondary reformer.
Secondary Reformer
Air is introduced as the nitrogen source. The oxygen burns off and additional reforming takes place in another catalyst bed, leaving a mixture of nitrogen, hydrogen, carbon oxides and other gases.
Shift Conversion
The carbon monoxide is converted to carbon dioxide with the assistance of catalyst beds at different temperatures.
Carbon Dioxide Removal
Carbon dioxide is removed by washing the gas mixture with a potassium carbonate solution.
Methanator
The gas steam, basically nitrogen and hydrogen, is passed over another catalyst bed in the methanator, where trace amounts of carbon oxides are converted back to methane.
Syngas Compressor
Here, the mixture of hydrogen and nitrogen (H2 and N2) is compressed.
Synthesis Converter
After leaving the compressor, the mixture goes through catalyst beds in the synthesis converter where ammonia (NH3) is produced with a three-to-one hydrogen-to-nitrogen ratio. However, not all the hydrogen and nitrogen are converted to ammonia.
Separator
The unconverted hydrogen and nitrogen are separated from the ammonia in the separator and re-cycled back to the syngas compressor.
Ammonia Storage
Ammonia is stored in tanks as a refrigerated liquid. Some ammonia is used directly as a fertilizer. Most ammonia is converted in downstream processes to urea (46% nitrogen) or ammonium nitrate (34% nitrogen) for use as fertilizer.
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