Heterogeneous catalytic reaction of elemental mercury vapor over cupric chloride for mercury emissions control

Authors:   Xin Li, Zhouyang Liu, Jinsoo Kim, Joo-Youp Lee

Abstract:
In this study, the reaction mechanism of Hg(0) vapor oxidation over cupric chloride (CuCl₂) was investigated using 10% (wt) CuCl₂/α-Al₂O₃ for mercury emissions control from coal-fired power plants. The CuCl₂/α-Al₂O3 sample showed >90% Hg(0) oxidation with excellent resistance to SO₂ at 140 ◦C in a simulated flue gas containing 10 ppmv HCl, 2000 ppmv SO₂, and 6% O₂ gases balanced with N₂ gas. In the absence of HCl and O₂ gases, Hg(0) vapor was found to be oxidized by consuming atomic Cl of CuCl₂ and reducing it to CuCl, following a Mars–Maessen mechanism. The reduced CuCl could be re-chlorinated back to CuCl₂ by replenishing empty Cl atoms under 10 ppmv HCl and 6% O₂ gases readily present in coal combustion flue gases even under 2000 ppmv SO₂ concentration for continuous Hg(0) oxidation. Cl₂ gas generation was not observed over CuCl₂ at 140^◦C, indicating a heterogeneous catalytic reaction. CuCl₂ shows potential that can be realized in a honeycomb or plate catalyst bed.

Keywords:
Elemental mercury oxidation
Cupric chloride
Redox catalyst
Coal combustion flue gas

Published in: Applied Catalysis B: Environmental (Volumes 132–133, Pages 1-552, 27 March 2013)

Publisher: Elsevier  

ISSN Information: 0926-3373

Heterogeneous catalytic reaction of elemental mercury vapor over cupric chloride for mercury emissions control

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