Study Of Modified Activated Carbon On Catalytic Oxidation Of NO In Low Temperature

As air pollution is getting worse in recent years, the technology of flue gas denitration is getting more and more attention. Selective catalytic oxidation(SCO) is a new dry denitration technology, but it cannot be applied to industry because of some reasons, one of which is the difficulty in finding a suitable catalyst to catalytic oxidate NO. Now we use activated carbon(AC) as SCO catalyst and utilize impregnation method to modify it with nitric acid.And then we research how the catalytic activity changes and discuss the mechanism of catalytic reaction as well as the activated center. The result shows that after modification the catalytic activity of activated carbon improves significantly. Combined with BET、FTIR and TPD, it shows that there is no direct relationship between catalytic activity and pore structure of activated carbon. Moreover, nitro and carbonyl on the surface of activated carbon promote the NO conversion. We can speculate that the nitro and carbonyl may be one of the active centers. Besides, this article also investigates the selection of types of activated carbon, modification technology, reaction condition as well as the water-resistance and sulfur-resistance of catalyst. As know from the experimental data, the activity of catalyst without calcining can achieve best by modifying the coconut shell activated carbon with impregnation method in the concentration of nitric acid up to 20%. Under the condition that reaction temperature is 40℃, catalyst volume is 3.6ml, space velocity is 20000h-1, gas composition is φ(NO)=1000ppm,φ(O2)=4%, the rest with N2, the reaction conversion can reach up to 68.5%. However, the water-resistance and sulfur-resistance of activated carbon catalyst are not ideal. H2O can make the catalyst reversible inhibition; meanwhile SO2 can make it irreversible inhibition.