Study on Regeneration of Used SCR Catalysts Containing Ba

The regeneration of deactivated commercial selective catalytic reduction(SCR) catalysts is helpful to improve the economic efficiency of power plants and protect the environment. Take the example of the deactivated SCR catalysts containing Ba from a power plant as the study object, three methods, i.e., combined sodium hydroxide and citric acid cleaning, dilute sulphuric acid cleaning and ammonium sulfate solution cleaning, are adopted to conduct the regeneration processing of the catalysts. The physicochemical properties of the catalysts before and after the regeneration are tested, then the deactivation causes and the performance recovery are analyzed by various characterization and evaluation methods. Moreover, the regeneration effects of the three methods are compared. The results show that the deposit of the impurities such as BaSO₄, K and Na detected on the surface of the used catalysts are the root cause leading to the catalytic activity deterioration. The three regeneration methods can all remove the impurities of K and Na at different levels. After the regeneration the denitration efficiency is improved substantially at different molar ratios of ammonia to nitrogen, among which, ammonium sulfate solution cleaning method produces the most desirable effect.