Nitrogen oxides (NOx)
The high temperatures cause the release of nitrogen oxides because nitrogen (N) in the air reacts with oxygen (O). That happens in a number of different proportions (for example nitrogen monoxide, nitrogen dioxide, nitrous oxide). This group of nitrogen oxides and dioxides are therefore referred to as NOx.
The “deNox” process utilises two methods. Thermal deNOx takes place at very high temperatures. At lower temperatures, selective catalytic reduction is used (SCR). With this method, aqueous ammonia can also be used instead of ammonia (approx. 25% solution of ammonia in water).