Design Strategies for Development of SCR Catalyst: Improvement of Alkali Poisoning Resistance and Novel Regeneration Method

Abstract

Based on the ideas of the additives modification and regeneration method update, two different strategies were designed to deal with the traditional SCR catalyst poisoned by alkali metals. First, ceria doping on the V(2)O(5)-WO(3)/TiO(2) catalyst could promote the SCR performance even reducing the V loading, which resulted in the enhancement of the catalyst's alkali poisoning resistance. Then, a novel method, electrophoresis treatment, was employed to regenerate the alkali poisoned V(2)O(5)-WO(3)/TiO(2) catalyst. This novel technique could dramatically enhance the SCR activities of the alkali poisoned catalysts by removing approximately 95% K or Na ions from the catalyst and showed less hazardous to the environment. Finally, the deactivation mechanisms by the alkali metals were extensively studied by employing both the experimental and DFT theoretical approaches. Alkali atom mainly influences the active site V species rather than W oxides. The decrease of catalyst surface acidity might directly reduce the catalytic activity, while the reducibility of catalysts could be another important factor.

Efficient NH3-SCR removal of NOx with highly ordered mesoporous WO3(χ)-CeO2 at low temperatures

“…In thermal power plants and coal-fired boilers, the commercial V 2 O 5 -WO 3 /TiO 2 catalysts have been widely used. However, their working temperature window is too high, which is generally from 300 to 400 °C [5]. Moreover, several inevitable disadvantages of this commercial catalyst restrict its further usages, such as the toxicity of vanadium, weaker sulfur resistance, narrower and higher working temperature window, etc.…”

Regenerable magnetic octahedral layer catalyst for gaseous UPOPs removal

“…Previous studies considered K + as a toxicant to catalyst in flue gas treatment [19]. Our observations suggest that the role of K + should be re-considered in terms of chlorinate organics destruction.…”

“…In fact, it has already been proved that water-washing can efficiently remove soluble surface toxicant (i.e., alkali [19] and sulfate [20,21]) from deactivated catalysts. However, considering the hydrophilic property of OL [22], the recovery of OL from water phase will be a great challenge.…”

Rational Design of Alkali‐Resistant NO Reduction Catalysts using a Stable Hexagonal V‐Doped MoO3 Support for Alkali Trapping

“…Several ways have been reported for solving the problem of alkali poisoning: a) supports with stronger acidity can be used to interact preferentially with alkali metal ions to protect active species from alkali poisoning; b) “basic” transition metal oxides with less Brønsted acid sites can be used as active phases since they are not easily subject to alkali poisoning;, c) electrophoresis treatment or washing the alkali‐poisoned catalysts with water or diluted H 2 SO 4 can regenerate the alkali‐poisoned catalysts ,,. In addition, we recently established an ion exchange‐coordinate model as a guide for developing alkali‐resistant SCR catalysts .…”