Characters of Activated Carbon for Hg Removal of Flue Gas with H2S and Iron Oxide for Hg Removal of Coal Derived Fuel gas with H2S

Introduction The major anthropogenic sources of mercury emission are coal combustion and municipal waste incineration. However, it is very difficult to remove the mercury compounds, particularly elemental mercury vapor, which is not effectively captured in typical air – pollution control devices. It has been reported that activated carbon, particularly activated carbon impregnated with sulfur, chlorine, and iodine, are effective for Hg removal. However, the major drawbacks of activated carbons are high cost, poor capacity, narrow temperature range and slow regeneration and adsorption rates. We have presented a novel Hg removal method using H2S and adsorbents. This method based on the reaction of H2S and Hg over adsorbents. Although the reaction mechanism is not well understood yet, but it has been suggested in our previous report that Hg reacts with H2S and forms HgS. The sublimation point of HgS(cubic) is 446C. If the reaction (adsorption) between Hg and H2S over suitable adsorbent (catalyst) occurs at a temperature well below the sublimation point of HgS, then elemental mercury can be removed from the flue gas effectively. In this study, we tried to clarify the removal characters of an activated carbon and an iron oxide for the removal of Hg vapor: The activated carbon was useful for the Hg removal from a combustion flue gas; the iron oxide was useful for the Hg removal from a coal derived fuel gas.