Enhancing NOx removal in a high-gravity rotating packed bed with gaseous ClO2 oxidation-absorption: Kinetic, mass transfer, and cost analysis.

• A new method for NO oxidation using ClO 2(g) + RPB absorption is proposed. • Smaller doses of ClO 2(g) have comparable oxidation capacity to O 3. • Preliminary oxidation kinetic analysis predicts potential product distribution. • Favorable energy consumption leads to better NOx capture capacity. • ClO 2(g) oxidation with RPB absorption has better cost-effectiveness than scrubber technology. The application of ClO 2(g) for NO oxidation presents a promising approach to improving air pollution control technology. In this study, an integration of ClO 2(g) with absorption using a high-gravity rotating packed bed (HiGee RPB) was proposed for NOx removal. The results showed that ClO 2(g) has a comparable oxidation efficiency (close to 100%) to O 3 in converting NO to NO 2 , while the dosage of ClO 2(g) required was two times smaller than that of O 3. The gas-phase oxidation kinetic analysis between ClO 2(g) -NOx, using an ideal plug flow model, simulated the potential amount of NOx species produced in a short reaction distance in the pipeline. Furthermore, at higher gas-liquid ratios and in high-gravity fields, the effective mass transfer interfacial area for NO 2 absorption was mainly controlled by the liquid film rather than droplet behavior, resulting in decreased absorption capacity. The empirical model for predicting the gas-side mass transfer coefficient confirmed that the interaction between mass transfer performance and chemical absorption was independent. Therefore, selecting the appropriate absorbent is a key factor in achieving high-loading NO 2 concentrations after oxidation by ClO 2(g). Another interesting finding is that balancing system energy consumption and the target treated NOx concentration played a critical role in enhancing the NOx absorption capacity. The cost analysis showed that substituting existing scrubbers with RPB processes could facilitate NOx absorption capacity (g-NOx/kWh) with cost-effectiveness. Overall, this study provides valuable insights into the development of effective and efficient NOx removal technologies, and future research in this area can build on these findings. [ABSTRACT FROM AUTHOR]