FREMGANGSMAADE TIL FJERNELSE AF NITROGENOXIDER FRA AFGANGSGASSER

摘要

Process for eliminating nitrogen oxides NOx from residual gases contg. a large amt. of oxygen and/or oxygen cpds. e.g. nitrous oxide, the process being used in a plant mfg. adipic acid. The NOx are reduced by ammonia at high temp. employing as a catalyst a mixt. of an iron oxide and a chromium oxide. The catalyst is pref. distributed throughout several stages and part of the current of ammonia introduced before each stage, and the residual gas is pref. heated to 260-310 degrees C. for removal of the NOx. The residual gases arising in mfg. adipic acid contain up to 10000 ppm. NOx which is removed to avoid environmental pollution when the gases are discharged into the atmos. An economic process which is effective despite the presence of large amts. of O2 and N2O in the gas.