| 摘要 |
<p>1. Process for the removal of nitrogen oxides from waste gases, in which the waste gases containing the nitrogen oxides are treated with a circulated absorption fluid to absorb the nitrogen oxides, in which fluid the evaporated water is replaced by a corresponding quantity of fresh water, ozone being added to the waste gases to be freed from the nitrogen oxides in the gas phase to oxidise the nitrogen oxides contained in the waste gases, the amount of ozone, corresponding to the desired degree of separation of NO2 , such that the NO2 formed is absorbed in a subsequent absorption stage, ammonia or calcium compounds or sodium compounds having previously been added, and the absorption product obtained in this process is oxidised in a subsequent oxidation stage using a further oxidising agent to form ammonium nitrate or calcium nitrate or sodium nitrate and is then fed as a solution to an injection evaporator with subsequent pelletising or to a crystallisation plant, characterized in that, for setting a pH between 3.0 and 7.0, preferably between 3.5 and 5.5, a corresponding quantity of ammonia or a calcium compound or sodium compound is fed to the absorption stage to absorb of the NO2 .</p> |
