The Regeneration Effect of H_2SO_4 on V-W-TiO_2 SCR Catalyst Deactivated by Alkali Metal

摘要

The sodium content in Zhundong coal is extremely high, which can accelerate the deactivation of the V-W-TiO_2 selective catalytic reduction (SCR) catalysts. Sulfuric acid solution (H_2SO_4) washing has been verified as a famous method to regenerate the de-NO_x performance for catalyst which has been poisoned by alkali metals. However, the performance of the regenerated catalyst in practice still needs to be investigated. In the present study, the resistance to sulfur dioxide (SO_2) and the mechanical strength of the regenerated catalyst were experimentally studied as well as the continuous operation performances under several conditions. The results indicate that the de-NO_x activity of H_2SO_4 regenerated catalyst is chemically stable below 300 °C and thermally stable below 450 °C. However, the catalytic activity of the regenerated catalyst could suffer a decline during operating under the SCR atmosphere at 450 °C, which is different from the fresh catalyst. Besides, the regenerated catalyst shows good SO_2 resistance, whereas the mechanical strength is likely to be affected by the H_2SO_4 washing treatment.