Abstract: While the SCR flu-gas de-NO_x catalyst has been used widely, a large number of deactivated catalyst are produced. Thus it is of great importance to regenerate those deactivated catalysts for economic purpose and environmental protection. The deactivated SCR flue gas denitrification catalyst which has been put into operation for nearly 25 000 hours in a coal-fired power plant is taken as the research object. Based on the deactivation principle of the catalyst, the main influencing factors (compressed air soot blowing pressure, ultrasonic cleaning time, etc.) in the regeneration process of the catalyst are analyzed. Then the regeneration process of deactivated catalyst is introduced, including ash removal, pre-cleaning, deep cleaning, active component loading, heat treatment and so on. The various testing results show that the pollutants such as alkali metal, alkaline earth metal and sulfate in the deactivated catalyst are removed effectively after regeneration process with the developed technology. The through-cell ratio of the catalyst reaches up to 98.7%. The specific surface area is obviously recovered and the relative activity of the regenerated catalyst is remarkably improved to 99%. The compressive strength and the single layer SO₂/SO₃ conversion rate of the catalyst are able to satisfy the application requirements, which means the physicochemical properties, the process performance and the mechanical strength of regenerated catalyst are effectively recovered for the continuing usage in the denitrification reactor.

Key words: coal-fired power plant, flue-gas de-NO_x, SCR, catalyst, deactivated, regeneration