Suppressing Calcium Deactivation in Selective Catalytic Reduction of NOx from Diesel Engines Using Antimony
Suppressing Calcium Deactivation in Selective Catalytic Reduction

Resitoglu, Ibrahim Aslan

The selective catalytic reduction (SCR) of NOx emissions by hydrocarbons (HCs) using a silver (Ag)-based catalyst offers significant advantages over conventional SCR systems that rely on ammonia reductants and vanadium-based catalysts. However, the conversion rate of SCR is influenced by several factors, among which catalyst poisoning is a major concern. Toxic metals such as sodium (Na), potassium (K), magnesium (Mg), and calcium (Ca) can degrade catalyst activity and lead to deactivation. Poisoned catalysts suffer from reduced conversion rates and premature deactivation before reaching their intended operational lifespan. In particular, calcium poisoning results in the formation of CaO (calcium oxide), which reacts to produce a CaWO4 compound that severely impairs SCR performance. This st...