Production method of nitric acid at a concentration of 50 to 77.8 by weight

摘要

Disclosed it is possible to establish from about 50 to 77.8% by weight which can be industrially practiced, a method for producing a nitric acid concentration range around the azeotropic compound containing water in a simple way the interest. A above object, thereby obtaining a gas mixture comprising NO and O ₂ by the catalytic gas phase oxidation of process air and ammonia ultra stoichiometric ratio, the gas mixture comprising NO and O ₂ was cooled / concentrated, and NO further oxidized to _NO 2 / N 2 O 4 by O _2, thereby obtaining a gas stream comprising an aqueous solution and _NO 2 / N 2 O 4 containing nitric acid, and a _NO 2 / N 2 O 4 the _NO 2 / N 2 O 4 from the gas stream, is counter-current adsorption on process water in the adsorbent, the step of obtaining the adsorbent exhaust gas containing nitric acid and NO _X-ranging concentration of 50 to 77.8 wt% a method of concentration is to produce nitric acid in the range of 50 to 77.8 wt%, the water content of nitric acid is adjusted to a range of 50 to 77.8 wt%, and the NO _X-content of adsorbent exhaust gases adjusted to 20～500Ppm, the adjustment measures the moisture content of the process air to be introduced into the catalyst gas-phase oxidation continuously and in dependence on this, by adjusting the process water which is introduced into the adsorber It is achieved by a method characterized in that it is carried out. .FIELD 1