CuO–CeO₂/TiO₂ catalyst for simultaneous NO reduction and Hg⁰ oxidation at low temperatures

Abstract

CuO-CeO 2 /TiO 2 (CuCeTi) catalyst prepared by a sol-gel method was employed for the first time to simultaneously reduce nitrogen monoxide (NO) and oxidize elemental mercury (Hg 0 ) in the presence of ammonia (NH 3 ) at low flue gas temperatures. The combination of copper oxides and cerium oxides yielded apparent synergy for NO reduction and Hg 0 oxidation. Over 90% of NO reduction and over 80% of Hg 0 oxidation were simultaneously obtained on the CuCeTi catalyst at 200°C to 250°C under simulated coal combustion flue gas with a gas hourly space velocity (GHSV) of 54 000 h −1 which is more than 10 times higher than the actual GHSV in selective catalytic reduction (SCR) reactors. The well-dispersed active species and abundant chemisorbed surface oxygen on the CuCeTi catalyst were responsible for its excellent catalytic performance. Neither Hg 0 vapor in flue gas nor HgO loaded on the catalyst surface inhibited NO reduction by NH 3 at 200°C. In the absence of gas phase oxygen (O 2 ), NH 3 consumed surface oxygen and hence resulted in the deactivation of Hg 0 oxidation. In the presence of O 2 , neither NO nor NH 3 individually exhibited an inhibition on Hg 0 oxidation. However, Hg 0 oxidation over the CuCeTi catalyst was inhibited by the co-presence of NO and HH 3 . Fortunately, this inhibitive effect was entirely scavenged when a lower GHSV was adopted. This study reveals the feasibility of simultaneously reducing NO and oxidizing Hg 0 at low flue gas temperatures. Such knowledge is of fundamental importance in developing efficient, practical and economical NO and Hg 0 control technologies for coal-fired power plants.Catal. Sci. Technol. This journal is

Insights into the Inhibitory Effect of H2O on Hg‐Catalytic Oxidation over the MnOx‐Based Catalysts

“…Hence, Hg 0 should be removed from the coal‐fired flue gas. Catalytic oxidation is one of the promising methods to remove Hg 0 from flue gas ,. Using this method, Hg 0 will be oxidized to Hg 2+ , which will be then efficiently captured by the wet flue gas desulfurization (WFGD).…”

Removal of elemental mercury from flue gas by recyclable CuCl 2 modified magnetospheres catalyst from fly ash. Part 1. Catalyst characterization and performance evaluation

“…m FA is the newly generated fly ash, and 5% is the yield of magnetospheres from fly ash [24]. (4) The cost of step (5) can be estimated as: y suppliedðnÞ ¼ Dm cata:n Á ðA þ BÞ (5) The cost of the matched facility in power plant and the operation cost, that is the cost of step (3), are not took into account in this work.…”

“…Recently, different technologies for Hg 0 removal have being investigated, such as catalytic oxidation [4][5][6][7][8][9][10] and sorbent injection [11][12][13]. Among these available technologies, activated carbon injection (ACI) has been considered as the most effective control http://dx.doi.org/10.1016/j.fuel.2015.08.012 0016-2361/Ó 2015 Elsevier Ltd. All rights reserved.…”

Role of Ceria in the Design of Composite Materials for Elemental Mercury Removal

“…The Hg 0 removal process could be described by the Langmuir‐Hinshelwood mechanism, with the active surface oxygen playing a significant role in Hg 0 oxidation process. Similar synergistic phenomena have also been observed over CuO‐CeO 2 , CuO‐CeO 2 /TiO 2 , and CoO x ‐CeO 2 /TiO 2 catalysts …”