Uptake of NOX by activated carbons: bench-scale and pilot-plant testing Original Research Article

The possibility of selectively removing NOx from gas containing CO2, N2, O2, H2O, SO2 and NOx has been examined using bench-scale and pilot-scale experimentation. These results have shown that NO can be selectively sequestered from the gas if the oxygen concentration is high enough and the SO2 concentration is low enough. Oxygen enhances the amount of NO removed, and promotes the conversion of NO to NO2 (via NO + 1/2O2 → NO2) and the adsorption of NO2 within the carbonsʹ micropores. The carbon is not consumed if during NO2 desorption its temperature is maintained below about 200 °C. The presence of SO2 inhibits the oxidation of NO and the subsequent storage of NO2 within micropores but, at concentrations typical to gases after post-combustion sulfur scrubbers, such inhibition is an immediate effect probably associated with selective site poisoning rather than a cumulative effect associated with pore blocking or sulfur retention.