Correlating metal poisoning with zeolite deactivation in an individual catalyst particle by chemical and phase-sensitive X-ray microscopy.
Correlating metal poisoning with zeolite deactivation in an individual catalyst particle by chemical and phase-sensitive X-ray microscopy.
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DOI：
10.1002/anie.201210030
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发表时间：
2013-06-03
影响因子：
16.6
通讯作者：
Weckhuysen, Bert M.
中科院分区：
文献类型：
--
作者：
Ruiz-Martinez, Javier;Beale, Andrew M.;Deka, Upakul;O'Brien, Mathew G.;Quinn, Paul D.;Mosselmans, J. Fred W.;Weckhuysen, Bert M.
化学工业严重依赖于多相催化剂的使用。然而，更可持续的化学工艺的发展需要更好的催化剂配方，并最终为特定应用定制这些催化材料。一个典型的例子是流化催化裂化（FCC），它在工业上用于将重油馏分转化为更有价值的化学品，如汽油和烯烃。[1]来自原油的金属，特别是Ni和V，对FCC催化剂的有害影响是公认的。[2]金属破坏活性沸石相，其为超稳定沸石Y（USY）或沸石ZSM-5。结果，孔隙可达性和酸度降低，而有利于加氢-加氢反应，导致焦炭形成增加。在Ni的情况下，主要的有害影响是焦炭的形成，[3]而V中毒与高温蒸汽存在下的永久性沸石损伤有关。[2a]几个研究小组试图通过观察金属在50-150 mm FCC催化剂颗粒上和在不同催化剂组分之间的分布来理解金属中毒的机理，所述催化剂组分即沸石、基质（例如氧化铝和粘土）和添加剂，其构成FCC催化剂颗粒。这种表征研究大多采用侵入性表征方法进行。[4]这些研究表明，V比Ni更易移动的，并且更快地向FCC催化剂颗粒的内部前进。[4d]这些先前研究的主要缺点是它们需要侵入性制备步骤，其中FCC催化剂颗粒沿所需分析平面沿着切割。这种对分远非微不足道，在大多数情况下，观察到不同FCC组分分布的改变。因此，非侵入性方法有望提供有关金属毒物位置的更真实信息。此外，金属中毒和沸石失活之间的关系还没有很好地理解，迄今为止，还没有研究提供关于失活对单个FCC催化剂颗粒内的结晶沸石结构的影响的详细信息。在此，我们首次报道了在商业FCC装置中在单个催化剂水平上失活后金属毒物对沸石材料的有害影响粒子使用基于同步加速器的硬X射线辐射，可以在2D或3D中以微米分辨率确定Ni、V以及晶相的存在。此外，实验方法的非侵入性避免了FCC颗粒的预平分，避免了对催化剂材料的损坏和污染。我们的研究结果导致更好地了解在现实生活中发生的FCC催化失活过程，并打开了将这种方法应用于研究其他重要催化材料（包括金属和结晶相）的可能性。
Chemical industries heavily rely on the use of heterogeneous catalysts. The development of more sustainable chemical processes requires, however, better catalyst formulations and ultimately tailoring of these catalytic materials for a specific application. A showcase example is fluid catalytic cracking (FCC), which is industrially applied to convert heavy oil fractions into more valuable chemicals, such as gasoline and olefins.[1] The detrimental effect of metals originating from crude oil, especially Ni and V, on FCC catalysts is widely recognized.[2] The metals damage the active zeolite phase, being either ultrastable zeolite Y (USY) or zeolite ZSM-5. As a result, pore accessibility and acidity are decreased, while dehydrogenation–hydrogenation reactions are favored, leading to increased coke formation. In the case of Ni, the main detrimental effect is coke formation,[3] while V poisoning is associated with permanent zeolite damage in the presence of steam at high temperatures.[2a] Several research groups have attempted to understand the mechanism of metal poisoning by observing the distribution of metals across the 50–150 mm FCC catalyst particle and between the different catalyst components; that is, zeolite, matrix (for example, alumina and clay), and additives, which comprise the FCC catalyst particle. Such characterization studies have been mostly conducted with invasive characterization methods.[4] These investigations revealed that V is much more mobile than Ni and proceeds more quickly towards the interior of the FCC catalyst particle.[4d] The mayor drawback with these previous studies is that they require an invasive preparation step, where the FCC catalyst particle is cut along the desired plane of analysis. This bisection is far from trivial and in most of the cases an alteration in the distribution of the distinct FCC components is observed. Therefore, a non-invasive approach can be expected to deliver more truthful information about the location of metal poisons. Furthermore, the relationship between metal poisoning and zeolite deactivation is not well understood, and to date there are no studies providing detailed information about the effect of deactivation on the crystalline zeolite structure within an individual FCC catalyst particle.Herein we report for the first time the detrimental effect of metal poisons on the zeolitic material after deactivation in a commercial FCC unit at the level of a single catalyst particle. Using synchrotron-based hard X-ray radiation, the presence of Ni, V, as well as the crystalline phases can be determined with micrometre resolution in 2D or 3D. Furthermore, the non-invasive nature of the experimental approach avoids the pre-bisection of the FCC particle, avoiding damage and contamination to the catalyst material. Our findings lead to a better understanding of the deactivation processes taking place in real-life FCC catalysis and open the possibility to apply this approach for the study of other important catalytic materials, comprising both metals and crystalline phases.
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影响因子：
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作者：
Beale, Andrew M.;Paul, Michael;Fowles, Martin
通讯作者：
Fowles, Martin
影响因子：
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作者：
Buurmans, Inge L. C.;Ruiz-Martinez, Javier;Weckhuysen, Bert M.
通讯作者：
Weckhuysen, Bert M.
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作者：
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Vaccari, Angelo
影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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