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。
Ce-NaY zeolites with different cerium content were prepared by liquid phase ion exchange. The micro structure, textual properties and total acid content of the Y zeolites containing Ce were characterized by XRD, N2 adsorption and NH3-TPD. The influence of cerium on the acidity was studied by in-situ FTIR and the acid accessibility index（AAI）of Y zeolites before and after Ce modification were determined by different probe molecules. The micro-activities（MAT）of NaY/Ce-NaY zeolites were evaluated using Dagang light diesel as test feed. The results indicate that the original cage constructions of Y zeolites did not change after modification of cerium,while the crystal particle of Ce-NaY zeolites became smaller, and the pore structure turned to be more developed. With the introduction of more cerium,the extra-framework alumina reduced and the dealumination was suppressed, the AAI of Lewis acid gradually reduced and Bronsted acid AAI significantly increased,the MAT of REY zeolite is related with Ce content. The introduction of suitable amount of Ce species is very beneficial to improve the acid catalytic activity of the sieves.
出处
《石油炼制与化工》
CAS
CSCD
北大核心
2017年第6期14-19,共6页
Petroleum Processing and Petrochemicals
基金
国家自然科学基金项目(21376114)
