For a denitration catalyst used for industry

experimental study on deactivation of calcium sulfate and regeneration was carried out. Different regeneration solutions and conditions were investigated. Several analysis

like the X-ray diffraction(XRD)

X-ray fluorescence(XRF) and specific surface area analysis were employed to characterize the catalysts before and after the regneration

and the catalytic activities were also tested on a laboratory bench with simulated flue gas. The results show that

after the catalysts' inside micro pores were blocked or masked by calcium sulfate

the NO conversion ratio decreased sharply. A kind of acid which was called X in the paper could remove part of the calcium compounds

however

it had no effect on calcium sulfate. A kind of chelating agent which was called Y

blending with aqueous ammonia

acted well on removing calcium sulfate and recovering the specific surface area. The chelating agent Y worked better in basic solutions. The content of vanadium oxides in the catalysts decreased when washing with chelating agent Y

therefore reduced the NO conversion ratio.The ammonium vanadate aqueous solution was employed to replenish the vanadium oxides. After drying and calcination

the NO conversion rate was recovered as high as that of the fresh catalyst.