Abilities for removal of SOx and NOx as well as mechanical strength of some carbon blacks, active cokes, active carbons, PAN-ACF and sponge coke were tested using three kinds of reactors to evaluate them as a moving bed material for the dry simultaneous removal of SOx and NOx in the flue gas. Among the carbons texted, PAN-ACF A and B activated with H2SO4 had the highest catalytic activities for NO-NH3 reaction in a circulating reactor. The three active cokes, BF, Mitsui A and B cokes, were tested using a midget reactor (10m3/h) by repeating the operations of NO reduction with NH3 at 150°C, SOx removal at 150°C, and SO2 recovery at 400°C. An enhancement of catalytic and adsorption activity, maintaning the enough mechanical strength for the moving bed, was observed after several cycles of these operations. The coke gained through the cycles of SO2 adsorption and desorption no sulfur but some oxygens, which appear to be related to the enhanced activity.
A pilot plant of 1000m3/h was successfully operated with BF and Mitsui A cokes, which behaved as expected from the results obtained with a midget reactor. These results may indicate a practical application of a dry process for a simultaneous removal of SOx and NOx with active cokes in the moving bed. A better carbon such as PANACF which can be explored with ease by a circulating reactor can reduce the size and cost of the plant.