Reacting flow field simulation of Hg-0 oxidation in flue gas by ozone injection

Ozone injection is an effective way to oxidate Hg-0 in flue gas. The reacting flow field for the oxidation of Hg-0 by O-3 is numerically studied in detail with a reduced chemical mechanism in this paper. Based on sensitivity analysis with detailed chemical mechanism, a 12-steps reduced chemical mechanism is obtained and used in the following three-dimensional simulations of the reacting flow field. Through the reacting flow field simulation, the influence of various factors on Hg-0 oxidation efficiency is calculated and analyzed, such as O-3/NO molar ratios, jet velocities, moisture, temperatures, NO concentrations and Hg-0 concentrations. Results show that temperature and O-3/NO molar ratio are the key factors, jet velocity and NO concentration are the important factors, while water content has little effect. It is also found that the oxidation efficiency of Hg-0 is shown to be highly correlated with the amount of NO3 generated in the flue gas. Increasing the local generation of NO3 may be the key to achieve efficient oxidation of Hg-0. This study is good help of subsequent engineering applications.

Automated summary

This paper numerically studies the reacting flow field for the oxidation of Hg-0 by O-3 through ozone injection method. A reduced chemical mechanism is obtained and used to simulate the reacting flow field. The study reveals that temperature and O-3/NO molar ratio are key factors, while jet velocity and NO concentration are important factors for Hg-0 oxidation efficiency. Moreover, the amount of NO3 generated in the flue gas is highly correlated with the oxidation efficiency of Hg-0, suggesting that increasing the local generation of NO3 could improve the efficiency of Hg-0 oxidation. This study provides valuable insights for future engineering applications.