Montedison Alkaline NOx Abatement (Mont Alnoa). Compendium on Low- and Non-Waste Technology

摘要

Nitric acid manufacturing plants are characterized by single emission to the atmosphere, consisting of process tail gases. The stream is noxious due to the presence of nitrous oxides. The low waste technology applied to this process is a medium pressure (6-bar) process for soda (or potash) abatement of tail gases which permits a reduction of the NOX content in the gaseous emissions to levels below 200 ppm (Montedison Alkaline NOX Abatement). This step is inserted downstream of absorption and upstream of tail gas heating and expansion. A sodium (or potassium) nitrite solution is obtainable as a by-product from the alkaline abatement process; it may be oxidized to sodium nitrate and sold for commercial purposes.