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采用溶胶凝胶法制备TiO_2-SiO_2载体,浸渍法制备出V_2O_5-WO_3/TiO_2-SiO_2催化剂,利用BET、FESEM、XRD、TGA和激光拉曼对催化剂进行表征,研究催化剂的理化性质。以NH_3为还原剂,考察反应温度、SiO_2掺杂量、焙烧温度、空速和使用时间对SCR催化还原NO的性能影响。结果表明,V_2O_5-WO_3/TiO_2-SiO_2催化剂最佳反应温度在250~350℃。SiO_2掺杂能提高活性组分V_2O_5和WO_3在载体表面的分散性,制备出的催化剂具有更大的比表面积和更宽的温度区间,提高脱硝活性及稳定性。SiO_2掺杂量对催化剂性能影响较大,制备的催化剂中,TiO_2/SiO_2=2显示了最大催化活性,脱硝率均在60%以上,TiO_2/SiO_2=0.5制备的催化剂稳定性最差。焙烧温度对催化剂性能也有影响,焙烧温度在500和600℃时,最低脱硝率为58%和23%,最佳焙烧温度为400℃,脱硝率均在80%以上,具有优越的脱硝性能。实验结果还表明,空速对V_2O_5-WO_3/TiO_2-SiO_2催化剂的影响不大,在20 000 h~(-1)空速下催化剂的使用时间对脱硝率的影响也不大,48 h内能保持在99%左右,非常稳定。
V2O5-WO3 / TiO2-SiO2 catalysts were prepared by sol-gel method. The catalysts were characterized by BET, FESEM, XRD, TGA and laser Raman spectroscopy to study the physico-chemical properties of the catalysts. The effects of reaction temperature, amount of SiO 2, calcination temperature, space velocity and reaction time on the performance of SCR catalytic reduction of NO were investigated using NH_3 as reductant. The results show that the optimum reaction temperature of V_2O_5-WO_3 / TiO_2-SiO_2 catalyst is 250 ~ 350 ℃. SiO 2 doping can improve the dispersibility of the active components V 2 O 5 and WO 3 on the surface of the carrier. The prepared catalyst has larger specific surface area and wider temperature range, and improves the denitration activity and stability. The amount of SiO_2 doping has a great influence on the catalyst performance. In the prepared catalyst, the maximum catalytic activity of TiO_2 / SiO_2 = 2 shows that the denitrification rate is above 60%, and the catalyst prepared with TiO_2 / SiO_2 = 0.5 has the worst stability. The calcination temperature has an influence on the catalyst performance. When the calcination temperature is 500 and 600 ℃, the minimum denitrification rate is 58% and 23% respectively. The optimum calcination temperature is 400 ℃ and the denitrification rate is above 80%. The experimental results also show that the space velocity has little effect on the V 2 O 5 -WO 3 / TiO 2 -SiO 2 catalyst, and the effect of the catalyst time on the denitrification rate is not significant at a space velocity of 20 000 h -1. Maintain at about 99%, very stable.