NOx removal in a rotating packed bed: Oxidation and enhanced absorption process optimization

Abstract In view of the continuously stringent standard of nitrogen oxides (NO x ) emissions, developing new technologies for NO x removal or updating the existing NO x removal system is very urgent. This work introduces a novel technology for NO x removal in an RPB reactor by the combination of oxidation and enhanced absorption. Experimental results show that a rotating packed bed (RPB) reactor, having high gas-liquid mass transfer efficiency, is a more appropriate choice for NO x removal. Then a series system combining firstly a stirred tank reactor (STR) and secondly an RPB reactor, has been developed in order to oxidize more NO to NO 2 that is very soluble and enhances the subsequent absorption in the RPB reactor. The higher oxidation degree (~99%) was achieved with a sodium chlorite concentration of 0.10 mol L −1 and a liquid volume of 5.0 L in the STR. An absorbent containing sulfonated cobalt phthalocyanine (CoPcS) was employed in the RPB reactor to meet the demand of very efficient denitrification for a long-term running. Compared to the traditional urea/sodium chlorite composite absorbent in a single RPB system, the total NO x removal efficiency increased by approximately 30% through the absorbent containing CoPcS in a series system under the optimized conditions.