摘要
以水热合成法制备了结晶度良好的硼硅MFI沸石,对其进行碱处理并在此过程中添加Al^(3+)以达到脱硼补铝的目的,得到具有不同孔结构和酸性质的多级孔分子筛。采用X射线衍射(XRD)、扫描电镜(SEM)、物理吸附和氨气程序升温脱附(NH_(3)-TPD)等手段对合成的分子筛进行了表征,并在固定床反应器中考评了分子筛样品催化甲醇制丙烯(MTP)反应的性能。结合MTP反应评价和反应后分子筛样品的热重分析,发现碱处理过程中选择适宜的NaOH浓度有利于丙烯选择性提高,同时降低积炭速率。实验结果表明:在甲醇空速为3 h^(-1)的条件下稳定运行600 h,甲醇转化率大于99%,丙烯选择性保持稳定,失活催化剂积炭量约为40%(质量分数),催化剂容炭能力良好。
Boron-silicon MFI zeolites with good crystallinity were prepared by hydrothermal synthesis method.Alkali treatment to them was carried out with Al^(3+)addition to achieve the purpose of boron removal and aluminum insertion.Hierarchical molecular sieves with different pore structures and acid properties were obtained.The prepared sieves were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM),physical adsorption,NH_(3) temperature programmed desorption(NH_(3)-TPD)and other means.And the catalytic performance of zeolite samples for methanol to propylene(MTP)reaction was evaluated in a fixed bed reactor.Combined with the MTP reaction evaluation and the thermogravimetric analysis of the molecular sieve samples after the reaction,it was found that the selection of appropriate NaOH concentration in the alkali treatment process to zeolites was conducive to the improvement of propylene selectivity and the reduction of carbon deposition for MTP reaction catalyzed by the prepared sieves.The results of long-term running test showed that the methanol conversion was higher than 99% and the propylene selectivity remained stable during a stable operation of 600 h with methanol space velocity of 3 h^(−1).The coke deposition amount of the deactivated catalyst was about 40% mass fraction,indicating the good carbon capacity of the catalyst.
作者
徐滋溥
刘民
郭新闻
XU Zipu;LIU Min;GUO Xinwen(State Key Laboratory of Fine Chemicals,School of Chemical Engineering,Dalian University of Technology,Dalian 116024,China)
出处
《化学反应工程与工艺》
CAS
2022年第5期385-393,共9页
Chemical Reaction Engineering and Technology
基金
国家自然科学基金项目(21972013)
关键词
甲醇制丙烯
ZSM-5
催化剂
碱处理
积炭
methanol to propylene
ZSM-5 catalyst
alkaline treatment
carbon deposition
