title: Life and death of a single catalytic cracking particle.
abstract: Fluid catalytic cracking (FCC) particles account for 40 to 45% of worldwide gasoline production. The hierarchical complex particle pore structure allows access of long-chain feedstock molecules into active catalyst domains where they are cracked into smaller, more valuable hydrocarbon products (for example, gasoline). In this process, metal deposition and intrusion is a major cause for irreversible catalyst deactivation and shifts in product distribution. We used x-ray nanotomography of industrial FCC particles at differing degrees of deactivation to quantify changes in single-particle macroporosity and pore connectivity, correlated to iron and nickel deposition. Our study reveals that these metals are incorporated almost exclusively in near-surface regions, severely limiting macropore accessibility as metal concentrations increase. Because macropore channels are "highways" of the pore network, blocking them prevents feedstock molecules from reaching the catalytically active domains. Consequently, metal deposition reduces conversion with time on stream because the internal pore volume, although itself unobstructed, becomes largely inaccessible.
authors.affiliation: Debye Institute for Nanomaterials Science, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, Netherlands.
authors.forename: Florian
authors.initials: F
authors.lastname: Meirer
authors.affiliation: Debye Institute for Nanomaterials Science, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, Netherlands.
authors.forename: Sam
authors.initials: S
authors.lastname: Kalirai
authors.affiliation: Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA. ; Research Centre for Catalysts, Albemarle Corporation, 13000 Baypark Road, Pasadena, TX 77507, USA.
authors.forename: Darius
authors.initials: D
authors.lastname: Morris
authors.affiliation: Research Centre for Catalysts, Albemarle Corporation, 13000 Baypark Road, Pasadena, TX 77507, USA.
authors.forename: Santosh
authors.initials: S
authors.lastname: Soparawalla
authors.affiliation: Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors.forename: Yijin
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Research Centre for Catalysts, Albemarle Corporation, 13000 Baypark Road, Pasadena, TX 77507, USA.
authors.forename: Gerbrand
authors.initials: G
authors.lastname: Mesu
authors.affiliation: Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors.forename: Joy C
authors.initials: JC
authors.lastname: Andrews
authors.affiliation: Debye Institute for Nanomaterials Science, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, Netherlands.
authors.forename: Bert M
authors.initials: BM
authors.lastname: Weckhuysen
keywords: Catalysis; Catalyst deactivation; Chemical Imaging; Chemistry; Crude Oil Processing; Fluid Catalytic Cracking; Metal Poisons; X-ray Microscopy; Zeolite