Bachelor of Science, McMaster University (2010)
Master of Science, McMaster University (2012)
Doctor of Philosophy, Universiteit Utrecht (2016)
- Nanoscale Chemical Imaging of an Individual Catalyst Particle with Soft X-ray Ptychography ACS CATALYSIS 2016; 6 (4): 2178-2181
Life and death of a single catalytic cracking particle.
2015; 1 (3)
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.
View details for DOI 10.1126/sciadv.1400199
View details for PubMedID 26601160
View details for PubMedCentralID PMC4640619
Mapping Metals Incorporation of a Whole Single Catalyst Particle Using Element Specific X-ray Nanotomography
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
2015; 137 (1): 102-105
Full-field transmission X-ray microscopy has been used to determine the 3D structure of a whole individual fluid catalytic cracking (FCC) particle at high spatial resolution and in a fast, noninvasive manner, maintaining the full integrity of the particle. Using X-ray absorption mosaic imaging to combine multiple fields of view, computed tomography was performed to visualize the macropore structure of the catalyst and its availability for mass transport. We mapped the relative spatial distributions of Ni and Fe using multiple-energy tomography at the respective X-ray absorption K-edges and correlated these distributions with porosity and permeability of an equilibrated catalyst (E-cat) particle. Both metals were found to accumulate in outer layers of the particle, effectively decreasing porosity by clogging of pores and eventually restricting access into the FCC particle.
View details for DOI 10.1021/ja511503d
View details for Web of Science ID 000348483500026
View details for PubMedID 25555190
View details for PubMedCentralID PMC4435782
- Agglutination of single catalyst particles during fluid catalytic cracking as observed by X-ray nanotomography CHEMICAL COMMUNICATIONS 2015; 51 (38): 8097-8100