Characterization of a Fluidized Catalytic Cracking Catalyst on Ensemble and Individual Particle Level by X‐ray Micro‐ and Nanotomography, Micro‐X‐ray Fluorescence, and Micro‐X‐ray Diffraction

Abstract

A combination of advanced characterization techniques: synchrotron X‐ray micro‐ and nanotomography, micro‐X‐ray fluorescence, and micro‐XRD have been used to characterize a commercial spent equilibrium fluid catalytic cracking catalyst (ECAT) at both the ensemble and individual particle level. At the ensemble level, X‐ray microtomography was used to determine the average size, shape, and respective distributions of over 1200 individual catalyst particles. This information is important to determine performance in commercial operation. It is shown that a large fraction of the particles contained large internal voids (5–80 μm diameter), and these voids likely aid the accessibility for large hydrocarbon molecules. At the individual particle level, by using X‐ray nanotomography, these voids were visualized at a much smaller scale (≈100 nm–12 μm in diameter). In addition, the individual phases that are present in the particle, for example, TiO2 and clay, are readily visualized in 3 D. Micro‐X‐ray fluorescence (XRF) was used to map, and semiquantitatively determine, both the contaminant (Ni, V, Fe) and inherent (La) catalyst elemental distributions. The distribution of zeolite Y in the ECAT particle was inferred from the La XRF map. Micro‐XRD determined the lattice constant of the zeolite Y at the individual catalyst particle level. This in‐depth characterization study at the ensemble and individual ECAT particle level presents a robust methodology that provides an understanding of the ECAT at both the micro‐ and nanometer scales.

Relating structure and composition with accessibility of a single catalyst particle using correlative 3-dimensional micro-spectroscopy

“…1, the morphological information obtained by nano-TXM is displayed. The particle appears to be a typical FCC catalyst particle when compared with previous studies181920212941: it has a diameter of about 40 μm, shows a denser surface layer of 1–2 μm thickness and a complex macro-pore structure throughout the rest of the particle; the total porosity was determined to 18.8%. In this study, we additionally performed a pore throat analysis45, which revealed a pore throat size distribution peak at about 320 nm.…”

Tailoring and visualizing the pore architecture of hierarchical zeolites

“…Furthermore, no information about size and shape of the mesopores can be obtained because the resolution is limited. [171][172][173] Recently, Mitchell et al used synchrotron radiation X-ray tomography microscopy (SRXTM) to visualize the internal pore architecture of an industrial granule consisting of hierarchical alkaline-treated ZSM-5 zeolite and the binder attapulgite. Besides imaging porosity, the recently developed optical method based on microimaging by interference and infrared microscopy was successfully used to monitor diffusion of non-fluorescent guest molecules, such as methanol and ethanol, through nanoporous zeolites.…”

Management and valorisation of wastes through use in producing alkali‐activated cement materials

“…SEM image of a spent fluid cracking catalyst particle, showing a spherical particle morphology and absence of micron‐scale pores, as well as bright regions which are likely to correspond to high local concentrations of heavy metals. From Bare et al , copyright John Wiley & Sons.…”