Simultaneous Removal of NOx and SOx from Flue Gases Using ClO₂: Process Scaling and Modeling Simulations

The concept of coabsorption of NO 2 and SO 2 from flue gases, in combination with the enhanced oxidation of NO by ClO 2 (g), is studied on three scales, 0.2, 100, and 400 N m 3 /h, all with flue gases of different origins. The results obtained from each setup are presented, together with modeling that was applied to assess the scale-up of the concept and to validate the model. The measurements confirm that ClO 2 is highly selective toward NO oxidation for temperatures in the range of 70–155 °C. A comparison of the results obtained for each scale reveals that the 0.2 N m 3 /h setup confers a higher level of NO x absorption than the other setups, although the trends remain similar. Simulations of the results underpredict the level of NO 2 absorption in the 0.2 N m 3 /h setup while capturing the levels of absorption in the 100 N m 3 /h setup. An important finding is the rapid and complete oxidation of S(IV) in the presence of NO 2, which is not represented in the reaction kinetics.