Toward a viable ecological method for regenerating a commercial SCR catalyst – Selectively leaching surface deposits and reconstructing a pore landscape

Research on structural strengthening technology for regenerative denitration catalysts

“…7,8 SCR catalysts are affected by dust and water vapor in flue gas during operation, leading to wear and a lower compressive strength of the spent SCR catalyst surface. 9,10 Long-term operation at high temperatures can easily cause clogging and sintering of vanadium and titanium SCR catalysts, thus severely wearing the catalyst surface and further degrading the catalyst strength. 11 Regeneration techniques for deactivated SCR catalysts include water-wash regeneration, 12,13 thermal reduction regeneration, 14,15 acid (alkali)-wash regeneration, 12,16 and compound regeneration.…”

Formic Acid-Mediated Regeneration Strategy for As-Poisoned V2O5-WO3/TiO2 Catalysts with Lossless Catalytic Activity and Simultaneous As Recycling

“…9,10 Preliminary statistics suggest that the annual production of spent SCR catalysts in China had reached up to 2.4 × 10 5 m 3 /a after 2020. 11 Because of the heavy metal content, spent SCR catalysts are categorized as hazardous waste, which is a potential threat to the environment and requires a high cost for processing the wastes. 12 In consideration of the very high cost, environmental risk, and resource wastage of replacing deactivated commercial catalysts, regeneration and recycling of spent V 2 O 5 -WO 3 /TiO 2 catalysts are highly desirable.…”

“…Selective catalytic reduction (SCR) denitrification as the state-of-the-art NO x emission control technology has been practiced worldwide in power plants for a long time. − The commercial SCR catalyst is commonly composed of V 2 O 5 -WO 3 /TiO 2 , which is very expensive (3500–4000 $/ton) and makes up around half of the total cost of the SCR control system . However, the severe deactivation and short operating life is a grand challenge for these catalysts due to the complex composition of industrial flue gas, including heavy metals, alkali/alkaline-earth metals, and sulfur dioxide. , Preliminary statistics suggest that the annual production of spent SCR catalysts in China had reached up to 2.4 × 10 5 m 3 /a after 2020 . Because of the heavy metal content, spent SCR catalysts are categorized as hazardous waste, which is a potential threat to the environment and requires a high cost for processing the wastes .…”

“…To date, great efforts have been made to achieve an environmentally friendly and economical approach for the regeneration treatment of As-deactivation catalysts. The main methods have been developed, including acid/alkali/H 2 O 2 leaching, advanced oxidation process, bioleaching microbe, and so on. ,,− However, in terms of regeneration efficiency and cost, two aspects still need to be improved. On the one hand, leaching of active ingredients (V and W) together with As removal should be suppressed.…”

Catalytic Removal of NOx on Ceramic Foam-Supported ZnO and TiO2 Nanorods Ornamented with W and V Oxides

“…Specifically, NOx needs to be removed from the flue gases, particularly in electric power stations where generally TiO 2 -SCR catalysts are used. Regenerating the spent TiO 2 -SCR catalysts is a significant problem that needs further improvement despite many available options [15,16]. Currently, industrial TiO 2 -based SCR systems suffer from surface deposits.…”