Regeneration of PbO-deactivated Mn-Ce/Ti-bearing blast furnace slag SCR catalyst: Washing and Mn-Ce reloading

• Published in: Fuel (Guildford) 2024-02, Vol.357, p.129992, Article 129992
• Main Authors: Kong, Ming, Zhang, Shengchao, Wang, Yunchuan, Song, Linjiang, Zhang, Handan
• Format: Article
• Language: English
• Subjects: Catalyst regeneration; NH3-SCR; PbO poisoning; Ti-bearing blast furnace slag
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2023.129992

[Display omitted] •H2SO4 pickling markedly improved redox capacity of the PbO-doped Mn-Ce/Ti-bearing blast furnace slag catalyst.•Optimal conditions for the poisoned catalyst cleaning were 1.5 mol/L H2SO4 pickling at 30 °C for 2 h.•MnOx-CeO2 replenishment enhanced chemisorbed oxygen content while facilitated Mnn+/Cen+ electronic transfers on the catalyst. The NH3-SCR of NOx from sintering flue gas can be hindered by PbO, deactivating catalysts and making its regeneration a significant challenge. To address this issue, a novel MnOx-CeO2/Ti-bearing blast furnace slag catalyst was developed and its Pb poisoning mechanism was previously elucidated. In this work, regeneration of Pb-poisoned catalyst was systematically evaluated, including washing with different agents and replenishing MnOx-CeO2 components. The optimal conditions for catalyst cleaning were 1.5 mol/L H2SO4 pickling at 30 °C for 2 h. The doped SO42− could interact with catalyst ingredients, generating sulfate substances that partly transformed into various active sulfur-bearing species. These species enriched the catalyst surface and led to the formation of new S-OH/S = O chemical bonds. Loading MnOx-CeO2 further improved the catalyst's redox capacity by facilitating electronic conversions and increasing chemisorbed oxygen Oα content. The regeneration process also enhanced catalyst surface acidity by generating new N = O and N-OH bonds (N = Mn, Ce), intensifying the adsorption and activation of gaseous NH3. The present work offers new insights into the regeneration of MnOx-CeO2/Ti-bearing blast furnace slag catalyst, particularly for their application in flue gas streams with high Pb content.