Date of Publication:2022-10-07

Journal:CIESC Journal

Volume:70

Issue:8

Page Number:3078-3085

ISSN No.:0438-1157

Key Words:"MnO_x; SO_2; activated carbon; sorption; flue gas; elemental mercury; MnO_x; SO_2"

CN No.:11-1946/TQ

Abstract:The MnO_x modified activated carbon (MnO_x/AC) was prepared by impregnation method to simulate the removal of elemental mercury in coal combustion flue gas. The effects of Mn loading on sorbent, sorption temperature and flue gas composition on removal performance of elemental mercury in simulated flue gas were investigated. Mechanism of SO_2 inhibition on mercury removal was revealed. The average Hg~0 removal efficiency on MnO_x/AC is 97.0% at 150℃ in 3 hours when Mn loading is 14% (mass) with 5% (vol) O_2 in simulated flue gas. A small amount of O_2 and trace amounts of HCl and NO promoted the removal of mercury in gas phase, while trace amount of SO_2 inhibited it. TG/DTG, XPS and Hg-TPD analyses of spent MnO_x modified activated carbon indicated that the inhibition of SO_2 on Hg~0 removal of modified activated carbon is due to the consumption of lattice oxygen in MnO_x by formation of sulfate that occupies active sites on the surface of 14Mn/AC. This inhibition of SO_2 on removal of elemental mercury could be effectively reduced by adding trace amount of NO.

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