Study On The Adsorption Of Different Mercury Forms From Flue Gas By Coal Char

As the largest source of anthropogenic mercury emissions, mercury emitted from coal-fired power plants has been identified as a hazardous pollutant to both human health and environment. Therefore, the control of mercury emission from coal-fired utilities is vital to mitigate global mercury pollution. In recent years, many studies have been conducted to evaluate the effectiveness of Hg0 adsorption by solid sorbents. These investigations will provide useful information for developing mercury emission control technologies.This paper mainly studied the coal char preparation under different kinds of coal, different heating rate, different retention time, at the same tima ,the paper studied the adsorption of mercury and chlorinated mercury with the coal char and modified coal char.First,this paper mainly focused on coal char preparation under different conditions. coal char was prepared using different coals (Datong coal and Xiaolongtan lignite) with different heating rate and varied retention time. Analysis of char found that coal rank, heating rate and retention time ould influence the surface area of coal char. Coal with lower range produced char with larger surface area. Char prepared at slowly rising temperature has the maximum surface. Among char prepared in quick heat condition, the char with a retention time of 15 minutes has the largest specific surface area.Meanwhile,two bench—scales that were mercury online analyzer and thermostatic release - adsorption apparatus were constructed. Separately studied mercury the adsorption of mercury and chlorinated mercury.Last, this paper also studied the adsorption of elemental mercury and chlorinated mercury by prepared char and char-based adsorbents which were modifed from raw char. The adsorption experiments were conducted in bench—scale. Specifically, the adsorption of Hg0 and chlorinated mercury were conducted using mercury online analyzer and thermostatic release - adsorption apparatus, respectively. From the study, the following conclusions were obtained. Hg0 and HgCl₂ could be adsorpted by both raw and modified char. The elemental mercury and chlorinated mercury adsorption abilities of raw char were positively correlated with the surface area of char. This indicated the adsorption of mercury by raw char belonged to physical adsorption. After modification, the adsorption capacity improved. This may be due to the surface functional groups (-Cl - OH) on modified char could promote Hg0 and HgCl₂ adsorption, which belonged to chemical adsorption.