Time- and space-resolved high energy operando X-ray diffraction for monitoring the methanol to hydrocarbons reaction over H-ZSM-22 zeolite catalyst in different conditions

SURFACE SCIENCE

卷:648

Article

del Campo, Pablo¹  Slawinski, Wojciech Andrzej¹  Henry, Reynald¹  Erichsen, Marius Westgard¹  Svelle, Stian¹  Beato, Pablo²  Wragg, David¹  Olsbye, Unni¹ 

[1] Univ Oslo, Dept Chem, SMN Ctr Mat Sci & Nanotechnol, POB 1033, N-0315 Oslo, Norway

[2] Haldor Topsoe, Nymollevej 55, DK-2800 Lyngby, Denmark

关键词: Methanol-to-hydrocarbons;    ZSM-22 zeolite catalyst;    Operando X-ray diffraction;    Mass spectrometry;    Co-feed;    Hierarchical;   

DOI  :  10.1016/j.susc.2015.10.049

来源: Elsevier

【 摘 要 】

The conversion of methanol to hydrocarbons (MTH) over H-ZSM-22 was studied by operando time- and space-resolved X-ray diffraction (XRD) at 370-385 degrees C and WHSV = 2 g/g hat the Swiss-Norwegian Beamline at ESRF. The performance of a commercial H-ZSM-22 sample was compared before and after acid-base treatment, and with and without propanol co-feed, respectively. N-2 adsorption, Scanning Electron Microscopy and propyl amine desorption experiments showed that acid-base treatment led to enhanced accessibility of acid sites, mainly due to the formation of mesopores between agglomerated H-ZSM-22 crystals. The catalytic set-up allowed us to simultaneously observe the catalyst activity and unit cell volume variations by time- and space-resolved HXRD in operando conditions. The expansion of the unit cell and final flattening at different positions in the catalytic bed matched very nicely with the catalytic activity gradients. Different scenarios provided different behaviors and gave insights in the effect of morphology and co-feed process on the activity in the MTH process. This technique is the only one which has so far been able to provide direct evidence of the behavior of the species inside the catalytic reactor. (C) 2015 Elsevier B.V. All rights reserved.

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