Effects of preparation conditions on the properties of the vanadium based middle-low temperature SCR catalysts modified with antimony and tungsten

Combined with the superior resistance to sulfur as well to water of antimony, and the ability of tungsten to increase the activity of vanadium-based catalysts, antimony and tungsten were used as promoters to prepare the V-W-Sb/Ti catalysts using impregnation method, and the denitrification of the modified catalysts made by different preparation conditions was investigated. The tests of the activity and the resistance to H₂O and SO₂ were carried out in a fixed bed reactor, and the catalysts were characterized by N₂ physical adsorption-desorption, X-ray diffraction, NH₃-TPD test and H₂-TPR. In the case of the selected catalyst formulation 3V₂O₅-5WO₃-2Sb₂O₃/90TiO₂, the experimental results show that the catalyst prepared by using antimony acetate as the precursor has better activity than that prepared by using antimony chloride as precursor; the catalyst prepared by calcination at 400℃ has higher denitrification efficiency than that prepared at 500℃; the difference in the number of impregnation steps has a limited effect on the activity of the catalyst. At the denitrification temperature of 180℃, and 10% (volume ratio) H₂O and 0.01%SO₂ added in the feed gas, under the same calcination temperature, the activity of the catalyst prepared by two-step impregnation and using antimony acetate as the precursor is only 2% higher than the catalyst prepared by one-step impregnation and using antimony chloride as the precursor, the latter one has a simple and convenient preparation process, so it has more industrial application value.