In situ regeneration of commercial NH3-SCR catalysts with high-temperature water vapor

The performance of a commercial NH3-SCR catalyst used for 20,000 h in a 660 MW coal fired power plant was evaluated after treated in situ with water vapor at 300-350 degrees C for 336 h. The conversion of NOx reached 91.4% after this water treatment. The recovery of catalytic activity is mainly due to the removal of potassium, arsenic and sulfate-containing deposits from the catalyst surface, as well as the increase of surface active oxygen species and specific surface area. These results indicate that commercial NH3-SCR catalysts are deactivated by the deposition of water-soluble substances and which can be in situ regenerated cost-effectively with high-temperature water vapor treatment.