Removal of NOx and SO2 from the Coal-Fired Flue Gas Using a Rotating Packed Bed Pilot Reactor with Peroxymonosulfate Activated by Fe(II) and Heating

An advanced oxidation process involving combined activation of peroxymonosulfate (PMS) by Fe(II) ions and heating for NO and SO2 removal from coal-fired flue gas was conducted for the first time in a rotating packed bed (RPB) pilot reactor. The major influencing factors, radical species, reaction mechanisms and products, the mass transfer process, and the kinetics of simultaneous removal of NOx and SO2 were investigated. The results indicated that the NO removal efficiency reached above 70%, while SO2 and NO2 were almost completely removed. As the temperature increased, the (NO)-N-center dot removal efficiency increased. Moreover, the intensity of SO4 center dot-, center dot OH, and O-1(2) radicals generated by the activated PMS and (NO)-N-center dot radical converted by the radical-radical reaction enhanced with the increasing temperature, assessed by the electron spin resonance spectroscopy test. The increased liquid flow led to a higher NO removal efficiency, and the increased gas flow played the opposite role. The increased rotational speed first resulted in an increase in the NO removal efficiency and then its decrease. Furthermore, the mass transfer coefficient obtained in this RPB was significantly higher than that in the conventional bubbling reactor. Finally, the NO removal process in the PMS/Fe(II)/RPB system was proved to be a pseudo-first-order reaction and was considered to be a fast reaction as the reaction process completed in the liquid film based on the investigation of the Hatta number, strengthening factors, and the liquid-phase reaction utilization efficiency. The pilot experiment is conducted to further study the main parameters affecting the chemical reaction on a certain scale device and to solve the problems that the laboratory cannot solve or discover, and it is the necessary link for the transformation of scientific and technological achievements.