5 research outputs found
Structural characterization of coke deposits on industrial spent paraffin dehydrogenation catalysts
Coke deposition on spent noble metal catalysts used in petroleum/petrochemical industries is of serious concern on account
of its impact on the catalyst deactivation and consequent loss in the production yield. In order to counteract the effects of coke
deposition, it is vital to know the location as well as the nature and composition coke deposited on the spent catalysts. In the
present study, spent Pt-Sn/Al2O3 catalysts used in the industrial reactors for selective dehydrogenation of C10–C13 n-paraffins
to mono-olefins at different coke loading (approximately 7–9%, w/w) were characterized. The characterization of coke deposits
were analyzed by the combination of analytical techniques including HPLC, solid-state 13CCP/MASNMR,and TGA.Average
structural information has been obtained from the quantitative analysis of NMR data. The results indicate that the nature of
coke present in the soluble coke extracts of spent catalysts is rich in alkylated mono- and diaromatics with low percentage of
polyaromatics whereas the nature of insoluble coke is highly polyaromatic (aromaticity, fa > 0.95). In addition, temperature
programmed oxidation studies by TGA reveals that the coke is deposited on the dispersed metal as well as on the support.
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