低温SCR三叶草形脱硝催化剂制备及催化反应机理的研究

发布时间：2018-12-10 15:25

【摘要】：氮氧化物(NOx)是全球大气污染主要污染物之一,以NH3作为还原剂的选择性催化还原技术,即NH3-SCR技术是目前应用最为广泛的氮氧化物脱除技术。本论文以分析纯偏钒酸铵、锐钛矿型钛白粉为主要原料,制备了三叶草形条状催化剂颗粒,通过改变焙烧温度,来考察其对于成型催化剂脱硝活性以及抗压机械强度的影响。结果表明,当焙烧温度为450℃时,催化剂样品具有最佳的脱硝催化活性以及抗压机械强度。通过DRIFTS研究了催化反应机理。结果表明,在低温条件下,NH3在催化剂表面主要吸附在在B酸位上和L酸位上;NO+O2的吸附分为双齿硝酸盐、(N2O2)2-、单齿硝酸盐、桥式硝基-亚硝酸盐物种以及表面吸附的N02等形式,但是相对于NH3的吸附来说,NO+02的吸附量是较少的;气相或弱吸附的NO2是NO主要反应的途径,Br(?)nsted酸位相对于Lewis酸位来说更容易参加反应,低温下的反应主要遵从L-H机理。通过改变催化剂制备过程中的干燥温度以及干燥时间来研究其对于催成型催化剂活性及抗压机械强度的影响,通过优化催化剂成型配方,找出最佳的H3BO3+SiO2添加量,并测试了最佳条件下的催化剂样品的抗水抗硫性。结果表明,在干燥温度为80℃,干燥时间为0.5 h时,催化剂样品具有最佳的脱硝催化活性以及抗压机械强度;添加H3BO3+SiO2量为7.5 %时,催化剂抗压机械强度提高最为明显,且稳定性较好。
[Abstract]:Nitrogen oxide (NOx) is one of the major pollutants in global air pollution. The selective catalytic reduction technology with NH3 as reducing agent, that is, NH3-SCR technology, is the most widely used nitrogen oxide removal technology at present. In this paper, the pure ammonium metavanadate and anatase titanium dioxide were used as the main raw materials to prepare the clover bar catalyst particles. By changing the calcination temperature, the effects of the catalyst on denitrification activity and compressive mechanical strength were investigated. The results show that the catalyst has the best denitrification activity and compressive mechanical strength when the calcination temperature is 450 鈩，

本文编号：2370808