不同制备条件对锑钨改性钒基中低温SCR催化剂性能的影响

结合锑较优的抗水抗硫能力与钨提高钒基催化剂活性的能力,采用浸渍法制备了以锑-钨为双助剂的V-W-Sb/Ti催化剂,并探究了不同制备条件对改性催化剂脱硝性能的影响。催化剂脱硝活性测试及抗水抗硫实验在固定床反应器中进行,并利用氮气物理吸附-脱附测试、X射线衍射、NH_3-TPD测试和H_2-TPR测试对催化剂进行表征。结果表明,在洁净气氛下,以3V_2O_5-5WO_3-2Sb_2O_3/90TiO_2为例,采用醋酸锑为前驱物制备的催化剂脱硝效率高于以氯化锑为前驱物制备的催化剂; 400℃下焙烧制备的催化剂较500℃焙烧制备的催化剂有更优的脱硝活性;而浸渍步数的差异对催化剂的脱硝活性影响有限。在180℃的测试条件下,通入10%H_2O与0.01%SO_2后,以醋酸锑为前驱物、采用两步浸渍并在400℃下焙烧制备的催化剂的脱硝活性仅比以氯化锑为前驱物、采用一步浸渍并在400℃下焙烧制备的催化剂脱硝活性高2%,而后者制备过程相对简单方便,因此,其更具有工业应用价值。

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.