Removing nitrogen and nitrous oxides in exhaust gas from nitric acid production by adding ammonia and circulating hot gas over beta=zeolite iron catalyst

摘要

Ammonia is used to simultaneously remove nitrogen oxides and nitrous oxide from a gas that has 100 - 7000 ppmv of these gases and also oxygen and water vapor. The volumetric ratio of ammonia to nitrogen oxides in the gas is 0.7 - 1.4. The gas is circulated over a beta-zeolite iron catalyst at 200 - 600 deg C. The catalyst may be made up of granules and a binding agent. The volumetric gas flow rate over the catalyst may be 100 - 50000 hour-1.