Impact of Sulfur Oxides on Mercury Capture by Activated Carbons

摘要

Recent field tests of mercury removal with activated carbon injection (ACI) have revealed that mercurycapture is limited in flue gases containing high concentrations of sulfur Oxides (SO_x). In order to gain amore complete understanding of the impact of SO_x on ACI, we tested mercury capture under varyingconditions of SO_2 and SO_3 concentration using a packed bed reactor and simulated flue gas (SFG). Thefinal mercury content of the activated carbons is independent of the SO_2 concentration in the SFG, butthe presence of SO_3 inhibits mercury capture even at the lowest concentration tested (20 ppm). Themercury content decreases as the sulfur content of the activated carbons increases from 1-10%. In oneextreme case, an activated carbon with 10% sulfur, prepared by H_2SO_4 impregnation, shows almost nomercury capacity. The results indicate that mercury and SO_x are in competition for the same bindingsites on the carbon surface.