NOx is the generic name given to Nitrogen Oxides. NOx is generated from many processes including nitration process, for both organic and several inorganic compounds (including a few important metals).
This is generated due to the partial degradation of Nitric Acid used in the nitration process, as well as to the final treatment of the "spent" acid.
These gases are also formed in the nitration of aromatic compounds (toluene, naphtalenes and many of their derivatives), including the production of practically all types of explosives, in the attack of some relevant metals (like copper, bismuth, etc.), in gold & silver refineries and also in the "Nitric Acid Concentration (NAC)" Plants.
BVRs NOx Absorption Plants, uses water or caustic solution as per the need.
Proper oxidation of NO is completed for the optimum absorption efficiency with minimal energy consumption. When absorbed with water Nitric acid produced can be re-used for re-use in the main process.