Abstract
The homogeneous oxidation of elemental mercury (Hg0) can promote Hg pollution control in coal-fired power plants, while the mechanisms and quantitative contributions of homogeneous reactions in Hg0 oxidation, especially the reactions between Hg and chlorine (Cl), are still unclear. Here, a numerical study on the homogeneous reactions of Hg was conducted within a 600 MW tangentially fired boiler for the first time. A novel Hg sub-model was established by coupling the thermodynamics, reaction kinetics and fluid dynamics. The results showed that the higher Cl content in coal was beneficial to the oxidation of Hg0. The homogeneous reactions of Hg mainly occurred in the vertical flue pass at low temperature. Hg0 was still the dominant Hg-containing species at the boiler exit, and the concentration of mercury chloride (HgCl2) was the highest among the oxidized mercury. When low-Cl coal was fired, the addition of a small amount of chlorine species into the boiler at the burnout area increased the ratio of HgCl2 by over 16 times without causing serious chlorine corrosion problems.
Highlights
Academic Editor: GiancarloCoal-fired utility boilers are the predominant anthropogenic mercury (Hg) sources in many regions around the world [1,2]
In order to validate the model used in this study, the simulation results were compared with the practical measured data from the coal-fired power plant
The average flue gas temperature on each cross-section was calculated, with the results shown in Figure 5 shows the temperature contour of the cross-section at 25 m, from which it can be seen that the ideal tangential combustion was formed in the primary zone
Summary
Coal-fired utility boilers are the predominant anthropogenic mercury (Hg) sources in many regions around the world [1,2]. Most mercury emitted to the atmosphere from coal-fired power plants is in the form of gaseous elemental mercury, which is difficult to remove. Considering the decisive role of the forms of mercury species in choosing the mercury removal approach, it is necessary to investigate the homogeneous reactions between mercury and other flue gas components for mercury emission control from coal-fired power plants. In addition to the homogeneous reactions of Hg, the flow field, the temperature field and the flue gas component distribution within the boiler were analyzed. The results of this work are of significance in understanding the mechanisms of homogeneous Hg reactions and will lay a foundation for efficient mercury pollution control in coal-fired utility boilers
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
