Nitrogen oxides removed from a gas - by absorption in sulphuric acid and conversion to nitrogen and water

摘要

The gas contains >=1 mole NO2 per mole NO, and through it is passed a >=80% soln. of H2SO4. After the H2SO4 is passed, NH3(NH4)2SO4, urea, or sulphamic acid is opt added to the acid to react with the absorbed N oxides followed by heating to 125-275 degrees C to convert the N oxides to N2 gas and H2O. The N oxides are readily absorbed by the H2SO4 and the products are innocuous.