Structural changes of FCC catalyst from fresh to regeneration stages and associated coke in a FCC refining unit: A multinuclear solid state NMR approach
IR@IIP: CSIR-Indian Institute of Petroleum, Dehradun
View Archive InfoField | Value | |
Creator |
Behera,Babita
Ray,S.S |
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Date |
2009-06-22T10:58:26Z
2009-06-22T10:58:26Z 2009-06-22T10:58:26Z |
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Identifier |
http://hdl.handle.net/123456789/237
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Description |
The changes in zeolitic structure (Y zeolite) of fresh, equilibrium, spent and regenerated FCC catalysts
obtained from an Indian FCC refining unit were investigated by 29Simagic angle spinning (MAS) and cross
polarization (CP)-MAS, 27Al MAS and multiple quantum MAS (MQMAS) NMR. Deconvoluted 29Si MAS
NMR along with 29Si CP-MAS NMR of these four catalysts provide the detailed local structural changes
occurring at all Si(nAl) sites. 27Al MAS NMR provides the relative changes of tetrahedral (Td) and
octahedral (Oh) aluminum sites of the FCC catalysts at different stages of the cracker. Second order
quadrupolar effect (SOQE) and quadrupole coupling constant (CQ) obtained from both computation of
27Al MQMAS and simulation of 27Al 1D MAS spectra of these catalysts give imposition of structural
asymmetries in Td and Oh sites that can be correlated with catalytic activities. Local structural changes are
explained by NMR and are supplemented by Si/Al ratio, shrinkage in unit cell size and crystallinity
obtained from XRD and BET. Si(3Al) sites of Y zeolite are found to be more deactivated and may be the
primary sites of coking. 13C single hard pulse excitation (SHPE)-MAS, CP-MAS, cross polarization-dipolar
dephasing (CPDD) NMR and CP dynamics analysis of hard coke extracted from the spent catalyst from the
FCC unit reveal essential structural properties and nature of coke
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Language |
en_US
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Subject |
FCC Catalyst
Coke Multinuclear solid state NMR NMR |
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Title |
Structural changes of FCC catalyst from fresh to regeneration stages and associated coke in a FCC refining unit: A multinuclear solid state NMR approach
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Type |
Article
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