Nitrogen oxides, very high pressure chemical reactions

Industrial fertilizer synthesis starts from ammonia synthesis, and ammonia is then easily oxidized in a separate reactor to nitric oxide over PtRh wire gauze catalyst. Formation of nitric acid requires further oxidation of nitric oxide to nitrogen dioxide (NO2) and absorption of the nitrogen dioxide in water. Overall, three different chemical process plants are used for the synthesis of nitric acid. The ammonia synthesis reaction takes place in a high-tem-perature, high-pressure reactor that requires recycling of products due to the thermodynamic limitations of chanical conversion. The ammonia oxidation reaction is very fast and takes place over a very small reactor length. Finally, nitric acid synthesis takes place in absorption columns. 

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