摘要
研究了不同硅铝比NaY沸石先混合再进行铵离子交换和水热处理对USY沸石孔结构和酸性质的影响。对改性所得的USY沸石进行X射线衍射、低温氮气物理吸附脱附、固体铝核磁、氨气程序升温吸附脱附、扫描电镜、投射电镜等表征分析,结果表明,混合改性所得USY沸石的相对结晶度为70%,孔分布比较集中,介孔体积为0.200 cm^(3)·g^(-1),最可几分布为10 nm,酸量较高。与高硅铝比NaY沸石单独改性所得USY沸石相比,能明显提高介孔体积和酸量。与低硅铝比NaY沸石单独改性所得USY沸石相比,能提高相对结晶度和酸量。与两种硅铝比NaY沸石分别改性后再进行机械混合所得的混合USY沸石相比,提高了酸量。混合改性USY沸石既含有丰富的介孔,又保留了较高的酸量。以重油为原料的催化裂化评价结果表明,混合改性所得USY沸石制备的催化剂与对比催化剂相比具有较好的重油转化能力,汽柴油总收率达到61.96wt%,焦炭收率为8.23wt%。
Two parent NaY zeolites with different framework silica to alumina ratios were mixed together, then modified by combining of ion-exchange and steaming treatment. The obtained zeolite USY was characterized by X-ray diffractometer(XRD),Nitrogen physisorption, 27Al solid state magic angle spining nuclear magnetic resonace(27Al MAS NMR), temperature-programmed desorption of ammonia(NH3-TPD), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The relative crystallinity of the one-pot USY zeolite was 70%. The mesopore volume was 0.200 cm^(3)·g^(-1) and mesopore size distribution was found to be present at about 10 nm. The obtained one-pot USY zeolite showed improved mesopore volume and higher acid amount compared with the USY prepared by the high silica to alumina ratio of the parent NaY zeolite. Compared with the USY zeolite prepared by the low silica to alumina ratio of the parent NaY zeolite, the one-pot USY showed higher crystallinity and acid amount. Compared with the mixture of two different USY zeolites, higher acid amount was observed for the one-pot USY. There is a balance between mesopore production and acidity preservation of the obtained USY zeolite. The results showed that catalyst with one-pot USY zeolite could improve VGO catalytic cracking, the yields of gasoline and diesel were 61.96wt%, and the yield of coke was 8.23wt%.
作者
郑庆庆
ZHENG Qingqing(Hongyang Yehua Engineering Technology Co.,Ltd,Beijing 102200,China)
出处
《石油科学通报》
2022年第4期604-612,共9页
Petroleum Science Bulletin
关键词
沸石
硅铝比
改性
孔结构
酸性
催化剂
催化
zeolite
silica to alumina ratio
modification
pore structure
acidity
catalyst
catalysis
