NOx abatement from stationary emission sources by photo-assisted SCR: Lab-scale to pilot-scale studies

• Photo-SCR was systemically investigated on TiO2-coated α-Al2O3/γ-Al2O3 photocatalyst.
• A pilot-scale photoreactor was designed and carried out in the real conditions of flue gas.
• NO2 was nearly suppressed in the reaction temperature range of 110–200 °C.
• Spent TiO2/γ-Al2O3 photocatalyst has been regenerated via desulfurization.
• Using hydrogen at 500 °C in 1 h could completely regenerate the spent photocatalyst.

In developing a higher activity for NOx abatement from stationary emission sources, photo-assisted selective catalytic reduction (photo-SCR) was systematically investigated over TiO2 supported on a spherical α-Al2O3/γ-Al2O3. The formation of NO2 was virtually suppressed in the reaction temperature range of 110–200 °C. The NOx removal efficiencies of TiO2/γ-Al2O3 photocatalyst at 120 °C for real flue gas (in pilot-scale photoreactor) and simulated flue gas (in lab-scale photoreactor) were 68–75% and 43.5%, respectively, in the presence of reducing reagent (C4H10). SEM and XPS techniques revealed that sulfur temporarily occupied the active sites of the photocatalyst, causing deactivation. Spent TiO2/γ-Al2O3 photocatalyst was regenerated via desulfurization by either air or hydrogen at 400–500 °C. The effects of regeneration temperature and regeneration time on the photocatalytic activity are methodically investigated, demonstrating that using hydrogen at 500 °C in 1 h could completely regenerate the spent photocatalyst.

Photo-assisted selective catalytic reduction was systemically investigated on a TiO2-coated α-Al2O3/γ-Al2O3 spherical supports photocatalyst by using C4H10 as a reductant under UV-light irradiation.Figure optionsDownload high-quality image (207 K)Download as PowerPoint slide