CIESC Journal ›› 2016, Vol. 67 ›› Issue (8): 3380-3386.DOI: 10.11949/j.issn.0438-1157.20160403

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Solid-state reaction mechanism of ammonium molybdate with LaHY

ZHANG Weiqing, GUO Wenguang, CHU Lili, KONG Lingpeng, JIN Guangzhou   

  1. Department of Chemical Engineering, Beijing Institute of Petro-Chemical Technology, Beijing 102617, China
  • Received:2016-03-31 Revised:2016-05-16 Online:2016-08-05 Published:2016-08-05
  • Supported by:

    supported by the National Basic Research Program of China (2012CB215002).

钼酸铵与LaHY固相反应机理

张伟清, 郭文光, 储丽丽, 孔令朋, 靳广洲   

  1. 北京石油化工学院化学工程系, 北京 102617
  • 通讯作者: 靳广洲
  • 基金资助:

    国家重点基础研究发展计划项目(2012CB215002)。

Abstract:

Mass loss behavior in air and solid-state reaction mechanism of ammonium molybdate with LaHY were investigated by TG-DSC technique, and the physical structure, specific surface area, and surface acid sites by XRD, BET and NH3-TPD techniques. It showed that surface speicies of Mo arising from decomposition of (NH4)6Mo7O24·4H2O, over solid-state reaction of (NH4)6Mo7O24·4H2O with LaHY, allocates in LaHY molecular sieve cage as molybdenum-oxygen clusters to form a single-phase complex nMoOx·LaHY. The single-phase complex contributes to the lattice shrinkage, the reduced lattice parameter a0, and the decrease in specific surface area. The as-prepared nMoOx·LaHY possesses a slightly variation of weak acid center sites, an increase in medium strong acid center sites, a slightly decrease in strong acid center sites, and an increase in total acid sites, in comaprision with LaHY. The hydrodesulfulrization (HDS) performance of the single-phase complex nMoOx·LaHY was evaluated by using 0.6% (mass) dibenzothiophene(DBT)/decane as the representative reactants. The conversion of DBT in HDS process at 290℃ and 310℃ over nMoOx·LaHY catalyst with 5.0% (mass) of Mo loading, reached 56.38% and 88.79% under conditions of 4.0 MPa, 20 h-1 of space velocity and 500:1 of H2/oil volumetric ratio, which increased 12 and 28 percentage than that of MoO3/Al2O3 with 20% (mass) of Mo loading, respectively. The nMoOx·LaHY catalyst exhibited higher activity for DBT HDS reaction.

Key words: TG-DSC, solid-state reaction, single-phase complex, DBT, HDS

摘要:

采用TG-DSC技术研究了钼酸铵和LaHY在空气气氛中的失重行为,考察了钼酸铵与LaHY的固相反应机理,用XRD、BET和NH3-TPD对其物相结构、比表面积和表面酸性进行了表征。结果表明,(NH46Mo7O24·4H2O分解产生的表相Mo物种借助固相反应以金属-氧簇定位在LaHY分子筛体相笼中形成nMoOx·LaHY单相复合体,引起分子筛的晶胞收缩,晶胞参数a0减小,比表面积下降。制备的nMoOx·LaHY较相应LaHY分子筛的弱酸中心变化较小,中强酸中心增加,强酸中心略有减少,总酸量增加。以质量分数为0.6%的二苯并噻吩/正癸烷溶液为模型反应物,评价了制备的nMoOx·LaHY催化剂的加氢脱硫性能。负载Mo质量分数为5.0%制得的nMoOx·LaHY催化剂在反应压力4.0 MPa,反应液时空速20 h-1,H2/原料液体积比500:1的实验条件下,290℃和310℃的二苯并噻吩加氢脱硫转化率达到了56.38%和88.79%,较相应负载Mo质量分数为20.0%制备的MoO3/Al2O3催化剂分别提高了约12个百分点和28个百分点,表现出了较高的二苯并噻吩加氢脱硫反应活性。

关键词: TG-DSC, 固相反应, 单相复合体, 二苯并噻酚, 加氢脱硫

CLC Number: