Low cost catalytic sorbents for NOx reduction. 2. Tests with no reduction reactives

Coal, char and activated char doped with model vanadium compounds (V₂O₅ and NH₄VO₃) and petroleum coke ash, PCA, (main metal components: V, Fe and Ni) have been tested as catalytic sorbents for NO reduction without the addition of a reduction reactive. The sorbents prepared have shown to be active for NO reduction at temperatures higher than 350 °C. The most efficient sorbents are those obtained from unactivated chars and doping with model vanadium compounds or PCA does not upgrade significantly their behaviour. On the other hand, for the samples prepared from activated char, an improvement of the reduction efficiency is observed after impregnation with model vanadium compounds or PCA.SSA of the samples does not play a relevant role on the NO reduction efficiency while surface chemistry significantly affect the samples’ behaviour: higher the CO₂/CO ratio determined by TPD, higher the NO reduction efficiency of the sample.Slightly higher NO conversions are observed for the samples loaded with pure compounds but PCA is perspective for producing catalyst doped activated carbons.