X‐ray Fluorescence Tomography of Aged Fluid‐Catalytic‐Cracking Catalyst Particles Reveals Insight into Metal Deposition Processes

Abstract

Microprobe X-ray fluorescence tomography was used to investigate metal poison deposition in individual, intact and industrially deactivated fluid catalytic cracking (FCC) particles at two differing catalytic life-stages. 3 D multi-element imaging, at submicron resolution was achieved by using a large-array Maia fluorescence detector. Our results show that Fe, Ni and Ca have significant concentration at the exterior of the FCC catalyst particle and are highly co-localized. As concentrations increase as a function of catalytic life-stage, the deposition profiles of Fe, Ni, and Ca do not change significantly. V has been shown to penetrate deeper into the particle with increasing catalytic age. Although it has been previously suggested that V is responsible for damaging the zeolite components of FCC particles, no spatial correlation was found for V and La, which was used as a marker for the embedded zeolite domains. This suggests that although V is known to be detrimental to zeolites in FCC particles, a preferential interaction does not exist between the two.

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.…”

Magnetophoretic Sorting of Single Catalyst Particles

“…[18,19] During the FCC process, the catalyst deactivates irreversibly due to dealumination and the accumulation of metals, mainly Fe, Ni, and V. While Ni and V decrease the yield by promoting for example, coke formation, Fe is supposed to deactivate the particles by creating a shell of reduced porosity on the particles outer surface, either via vitrification of the particle matrix in the presence of Fe and/or co-deposition of silica. [20][21][22][23][24][25][26][27][28][29] Therefore, during operation, to create a stable process efficiency, a fraction of catalyst is being replaced on a daily basis, resulting in a mixture called equilibrium catalyst (ECAT). To investigate their deactivation, FCC ECAT particles are often sorted based on their skeletal density, which is associated with metal loading and age.…”

The curious case of zeolite–clay/binder interactions and their consequences for catalyst preparation

“…4,[7][8][9] Until recently, limited academic research has been reported on such industrial catalysts, but a spate in the development of advanced characterization techniques able to probe the multi-dimensional parameters of these materials with high spatiotemporal resolution (and also non-invasively) has provided signicant insights into the structure-performance relationships of these closely guarded materials. [10][11][12][13][14][15][16][17][18][19][20] Particularly in the eld of Fluid Catalytic Cracking (FCC) particles and zeolite-based binder-bound extrudates and pellets for e.g. methanol-tohydrocarbon (MTH) catalysis, combinations of chemical imaging and structural imaging techniques, together with standard physicochemical characterization of the materials, have enhanced our knowledge into how these complex materials function.…”