Hierarchical composite catalysts of MCM-41 on zeolite Beta for conversion of heavy reformate to xylenes
Hierarchical composite catalysts of MCM-41 on zeolite Beta for conversion of heavy reformate to xylenes
复制标题
DOI：
10.1016/j.jiec.2021.04.003
复制
发表时间：
2021-04-24
影响因子：
6.1
通讯作者：
Alasiri, Hassan S.
中科院分区：
文献类型：
--
作者：
Ali, Syed A.;Almulla, Faisal M.;Alasiri, Hassan S.
采用原位水热法在β沸石上合成了MCM-41层状复合材料，对其进行了表征，并对其催化重质重整油转化为有价二甲苯的性能进行了评价。通过改变碱性溶液（0.10 ~ 0.45 M NaOH）的强度，系统地优化了β沸石的分级孔生成。用氧化铝粘结剂挤压得到的纳米复合材料，并以4.0 wt% Mo浸渍。表征结果表明，随着碱浓度的增加，中间相发生了从无序相到有序/无序相再到有序中间相的转变。双层复合沸石的二甲苯收率是母沸石β的1.4倍。加入分散良好的轻度氢化功能（4 wt.% Mo）有利于提高二甲苯收率和选择性。以中碱性（0.2 M NaOH）溶液制备的配方具有最佳的双峰孔结构，改善了脱烷基和转烷基转化，二甲苯收率为33.0% wt.%，二甲苯选择性比母体沸石β提高1.7倍。30 h稳定性试验表明，性能稳定，二甲苯收率高。因此，分级沸石β和MCM-41复合催化剂在重芳烃转化生产二甲苯中的潜在应用已经成功证明。(c) 2021韩国工业与工程化学学会。Elsevier B.V.版权所有。
Hierarchical composites of MCM-41 on zeolite Beta were synthesized by in-situ hydrothermal technique, characterized and their catalytic performance for converting heavy reformate into valuable xylenes was evaluated. Systematic optimization of the hierarchical pore generation was carried out by varying the strength of the alkaline solution (0.10-0.45 M NaOH) during disintegration of zeolite Beta. The nanocomposites obtained were extruded with alumina binder and impregnated with 4.0 wt% Mo. The characterization results indicate the transition of mesophase occurs from distinct disordered phase to ordered/disordered and then to ordered mesophase with increasing alkaline concentration. The xylene yield over the hierarchical composite zeolite was 1.4 times more than the parent zeolite Beta. Incorporation of a well-dispersed mild hydrogenation function (4 wt.% Mo) was advantageous in improving the xylene yield and selectivity. The formulation prepared with moderately alkaline (0.2 M NaOH) solution exhibited optimum bimodal pore structure and improved dealkylation and transalkylation conversion resulting in a xylene yield of 33.0 wt.% and 1.7 times enhancement in xylene selectivity over parent zeolite Beta. A 30 h stability test showed steady performance and xylene yields. Hence, a potential application of hierarchical zeolite Beta and MCM-41 composite catalysts for the conversion of heavy aromatics to produce xylenes has been successfully demonstrated.(c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.