Contrast-matching small-angle neutron scattering to monitor the accessibility of solvents to the porosity of coked FCC catalysts

M. Castro-Diaz, P.J. Hall, Colin Snape, S.D. Brown, R. Hughes

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Small-angle neutron scattering (SANS) has been performed on fresh and deactivated fluid catalytic cracking (FCC) equilibrium catalysts. The catalysts were coked using a vacuum gas oil feed and stripped for varying periods of time in standard microactivity test (MAT) and fluidized-bed reactors. BET surface areas and contrast-matching SANS were measured on these samples to elucidate the influence of coke on the catalyst porosity. It was found that significant contrast matching could be obtained by mixing the catalyst with deuterated methanol, and there was good agreement between the gas adsorption and SANS results in terms of the mesoporosity. SANS indicated that the level of closed porosity is negligible in the fresh catalyst but significant in the deactivated catalysts and that the level decreases as the total coke content is reduced during stripping. Furthermore, the use of d-dodecane demonstrated that SANS can also provide information about sieving effects caused by the catalyst structure.
LanguageEnglish
Pages6566-6571
Number of pages5
JournalIndustrial and Engineering Chemistry Research
Volume41
Issue number25
DOIs
Publication statusPublished - 2002

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Fluid catalytic cracking
Neutron scattering
Porosity
Catalysts
Coke
Gas adsorption
Gas oils
Fluidized beds
Methanol
Vacuum

Keywords

  • chemical engineering
  • neutrons
  • porosity
  • solvents

Cite this

Castro-Diaz, M. ; Hall, P.J. ; Snape, Colin ; Brown, S.D. ; Hughes, R. / Contrast-matching small-angle neutron scattering to monitor the accessibility of solvents to the porosity of coked FCC catalysts. In: Industrial and Engineering Chemistry Research. 2002 ; Vol. 41, No. 25. pp. 6566-6571.
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Contrast-matching small-angle neutron scattering to monitor the accessibility of solvents to the porosity of coked FCC catalysts. / Castro-Diaz, M.; Hall, P.J.; Snape, Colin; Brown, S.D.; Hughes, R.

In: Industrial and Engineering Chemistry Research, Vol. 41, No. 25, 2002, p. 6566-6571.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Contrast-matching small-angle neutron scattering to monitor the accessibility of solvents to the porosity of coked FCC catalysts

AU - Castro-Diaz, M.

AU - Hall, P.J.

AU - Snape, Colin

AU - Brown, S.D.

AU - Hughes, R.

PY - 2002

Y1 - 2002

N2 - Small-angle neutron scattering (SANS) has been performed on fresh and deactivated fluid catalytic cracking (FCC) equilibrium catalysts. The catalysts were coked using a vacuum gas oil feed and stripped for varying periods of time in standard microactivity test (MAT) and fluidized-bed reactors. BET surface areas and contrast-matching SANS were measured on these samples to elucidate the influence of coke on the catalyst porosity. It was found that significant contrast matching could be obtained by mixing the catalyst with deuterated methanol, and there was good agreement between the gas adsorption and SANS results in terms of the mesoporosity. SANS indicated that the level of closed porosity is negligible in the fresh catalyst but significant in the deactivated catalysts and that the level decreases as the total coke content is reduced during stripping. Furthermore, the use of d-dodecane demonstrated that SANS can also provide information about sieving effects caused by the catalyst structure.

AB - Small-angle neutron scattering (SANS) has been performed on fresh and deactivated fluid catalytic cracking (FCC) equilibrium catalysts. The catalysts were coked using a vacuum gas oil feed and stripped for varying periods of time in standard microactivity test (MAT) and fluidized-bed reactors. BET surface areas and contrast-matching SANS were measured on these samples to elucidate the influence of coke on the catalyst porosity. It was found that significant contrast matching could be obtained by mixing the catalyst with deuterated methanol, and there was good agreement between the gas adsorption and SANS results in terms of the mesoporosity. SANS indicated that the level of closed porosity is negligible in the fresh catalyst but significant in the deactivated catalysts and that the level decreases as the total coke content is reduced during stripping. Furthermore, the use of d-dodecane demonstrated that SANS can also provide information about sieving effects caused by the catalyst structure.

KW - chemical engineering

KW - neutrons

KW - porosity

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DO - 10.1021/ie000868y S0888-5885(00)00868-X

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