Experimental study on mercury removal by Taixi activated coke under complex atmosphere of flue gases

In order to clarify the adsorption characteristic of activated coke under complex atmosphere of flue gases, a series of tests were conducted with a bench-scale fixed bed reactor. The simulated flue gas was prepared by mixing main composition of flue gas with mercury vapors generated through permeation tube. The surface properties were characterized by FT-IR. The results show that the performance of mercury removal is related to the surface chemistry of activated coke,and the oxygen-containing functional groups are the important factor affecting the adsorption and catalysis of Hg⁰. The adsorption performance of Hg⁰ with activated coke is influenced by SO₂ obviously and inhibition is observed in the removal process. With increasing concentration of SO₂, from 400, 855 to 1 520 mL/m³, the concentration of Hg⁰ at the outlet of the reactor increased from 36, 43 to 48 μg/m³. The complex impact of NO on the adsorptive capacity of Hg⁰ is found that NO with lower concentration promotes the adsorption of elemental mercury while inhibits it at higher value in CO₂/N₂/O₂/NO/Hg⁰ system. The increasing concentration of NO with the stationary concentration of SO₂ has a promotion to mercury adsorption while O₂, NO, SO₂ and Hg⁰ exists simultaneously. However, the increasing concentration of SO₂ could enhance the mercury adsorption at initial stage and prevents it at the latter stage.