Ce改性对Y型分子筛酸中心可接近性及催化活性的影响

发布时间：2018-01-07 08:39

本文关键词：Ce改性对Y型分子筛酸中心可接近性及催化活性的影响　出处：《石油炼制与化工》2017年06期 　论文类型：期刊论文

【摘要】：以液相离子交换法制备了不同Ce含量的Ce-NaY分子筛,采用XRD、N2吸附-脱附、NH3-TPD等手段对分子筛微观结构、织构性质和总酸量等进行表征,采用原位FTIR光谱技术研究了Ce改性对分子筛酸性的影响,以不同探针分子测定改性前后分子筛的酸中心可接近性(AAI),并以大港轻柴油为原料对改性前后分子筛的催化裂化微反活性进行评价。结果表明:经不同含量的Ce改性后,NaY分子筛的骨架结构并未改变,但其颗粒更为精细,孔隙结构更为发达;随Ce含量的增加,分子筛的非骨架铝减少,脱铝过程得到抑制,L酸中心AAI降低、B酸中心AAI显著提高;Ce-NaY分子筛的催化裂化活性与Ce含量紧密相关,适宜含量Ce物种的引入对提高分子筛的酸催化活性十分有利。
[Abstract]:The ion exchange in liquid phase were prepared with different Ce content of Ce-NaY molecular sieve, by XRD, N2 adsorption desorption, NH3-TPD and other means of micro structure of molecular sieve, texture properties and total acidity were characterized. The research on Ce modified acid effect on molecular sieve by in situ FTIR spectroscopy, determination of acid center the molecular sieve accessibility to different probe molecules (AAI), and to evaluate the port light diesel oil as a raw material on the modified molecular sieve catalytic cracking and micro reaction activity. The results showed that the different content of Ce modified NaY molecular sieve skeleton structure has not changed, but the more particles the fine pore structure is more developed; with the increase of Ce content, the non framework aluminum molecular sieve reduces the dealumination process was inhibited, L acid decreased AAI, B acid AAI increased significantly; catalytic activity of Ce-NaY molecular sieve and Ce content are closely related, suitable content of Ce The introduction of species is very beneficial to improving the acid catalytic activity of molecular sieves.

【作者单位】：辽宁石油化工大学辽宁省石油化工催化科学与技术重点实验室;中国石油大学(华东)化学工程学院;
【基金】：国家自然科学基金项目(21376114)
【分类号】：TE624.9
【正文快照】： 稀土改性Y型分子筛(REY)在流化催化裂化反应中被广泛应用,关于稀土阳离子对Y型分子筛酸性及催化活性影响的研究从未间断。普遍认为,稀土物种可经离子交换首先定位于分子筛超笼,经焙烧迁移至SOD笼SI′位,通过极化作用增大超笼中桥羟基电子对密度,使分子筛的B酸强度提高[1-2]。

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