E3 Journal of Environmental Research and Management

E3 Journal of Environmental Research and Management Vol. 5 (4) pp. 062-070, April 2014; © E3 Journals; ISSN 2141-7466

Application of solid-state NMR methods in Coke characterization

Awatef Al-Adwani¹^*, Andreâ€™ Hauser¹, Fatima A. Ali¹
¹ Kuwait Institute for Scientific Research, P.O. Box 24 885, Safat 13 109, Kuwait
^*Corresponding Author E-mail: awadwani@safat.kisr.edu.kw
Accepted 17 March 2014

Abstract

Catalyst deactivation is a problem of great and continuing concern in residue hydroprocessing operations. It is widely accepted that the deactivation of hydrotreating catalysts is to a great extent caused by coke deposition. Three used commercial catalysts were studied by solid-state 13C NMR to derive structural information on the coke. 13C NMR spectral editing (cross polarization technique in combination with the polarization inversion pulse sequence) was applied to distinguish on the one hand between quaternary and tertiary aromatic carbon and on the other hand between secondary and primary aliphatic carbon. Structural parameters, derived from those NMR measurements in combination with the aromaticity from single pulse excitation 13C NMR and the H/C ratio from elemental analysis, have been used to obtain structural information on coke.

Keywords: Coke, solid-state 13C NMR spectral editing, coke structure elucidation.

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