Inhibition effect of naphthalene on V2O5-WO3/TiO2 catalysts for low-temperature NH3-SCR of NOx

Abstract

Coal tar in the glass furnace flue gas can poison the V2O5-WO3/TiO2 (VWTi) catalyst used for ammonia selective catalytic reduction (NH3-SCR) of NOx. Herein, naphthalene (Nap), as one of the main components of coal tar, was selected to investigate the poisoning effect of coal tar on VWTi catalyst in the range of 200–280 ℃. The experimental results showed that the activity of VWTi catalyst decreased sharply with the introduction of Nap vapor, and the NOx conversion was less than 20% after the introduction of 1 h at the temperature range of 200–280 ℃. The poison processing and mechanism were systematically investigated. It was found that the Nap preferentially consumes active oxygens on the catalyst to form phthalic anhydride (PA) with a higher boiling point, which covers the active sites and leads to the deactivation of VWTi catalyst. Temperature affects the accumulation of deposits and the conversion rate of Nap, thus poisoning effect of Nap on VWTi is temperature-sensitive. The deposited Nap can be removed at high temperatures. Therefore, the inactivated catalysts can be regenerated by high temperature treatment.