Clinker production is a high-temperature combustion process that generates nitrogen oxides (NOx), one of the most significant kiln emissions. To reduce these emissions, selective catalytic reduction (SCR) has been widely acknowledged as the best available technology. By Area Impianti SpA, Italy.

Among the NOx reduction techniques, selective catalytic reduction (SCR) is the best available technique to achieve the highest efficiency in NOx removal. SCR reduces NOx to N2 by ammonia (NH3) injection upstream of catalyst, via the following reactions:
4NO + 4NH3 + O2 → catalyst → 4N2 + 6H2O
6NO2 + 8NH3 → catalyst → 7N2 + 12H2O

As the efficiency of NH3 conversion is very high, the risk of non-reacted NH3 (ammonia slip) losses is very low.

In the cement sector, the DENOX SCR has two possible configurations:
1. high-dust set-up, between the preheater and dedusting system
2. low-dust configuration, downstream of the dedusting system.