Mercury reduction

Both post-combustion and pre-combustion processes are being evaluated for mercury emission reduction from coal powered power plants. Most of the post-combustion processes are based on the collection of the mercury with an activated carbon absorbent using a baghouse. Pre-combustion processes are based on the fact that the mercury present in most coals is associated with the pyrite. It has been demonstrated that based on the specific coal and the topsize of that coal, that significant amounts of the mercury can be removed through specific gravity beneficiation processes. In addition, KFx has demonstrated significant mercury removal through the reduction step in their process (vaporization of the mercury which is subsequently captured by an absorbent). Most of the emphasis on mercury reduction is being addressed through the use of the post-combustion lignite based activated carbon process. The lack of interest in the demonstrated pre-combustion processes is partially attributed to the demise of the US Department of Energy’s Coal Preparation Research Division and the elimination / downsizing of in-house coal research facilities.