Modeling elementary reactions in coke formation from first principles - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Molecular Simulation Année : 2009

Modeling elementary reactions in coke formation from first principles

Karen Hemelsoet
  • Fonction : Auteur
  • PersonId : 878605
Bert Minner
  • Fonction : Auteur
  • PersonId : 880643
Guy B Marin
  • Fonction : Auteur
  • PersonId : 878608
Michel Waroquier
  • Fonction : Auteur
  • PersonId : 878609

Résumé

Theoretical calculations are presented on elementary reactions which are important during coke formation in a thermal cracking unit. This process is known to proceed through a free radical chain mechanism. The elementary reaction steps that lead to the growth of the coke surface can be divided into five classes of reversible reactions : hydrogen abstraction, substitution, gas phase olefin addition to radical surface species, gas phase radical addition to olefinic bonds and cyclization. To identify the elementary reaction classes that determine the coking rate, all microscopic routes that start from benzene and lead to naphthalene have been investigated. It is found that initial creation of surface radicals, either by hydrogen abstraction or substitution and subsequent hydrogen abstractions, determines the global coking rate. The influence of the local polyaromatic structure on the kinetics of the hydrogen abstraction reactions is determined by performing calculations on a large set of polyaromatic hydrocarbons (PAHs). On basis of the BDE values six types of possible reactive sites at the coke surface can be distinguished. For the initial hydrogen abstraction the local polyaromatic structure strongly influences the reaction kinetics and abstraction is preferred from less congested sites of the polyaromatic.

Mots clés

Fichier principal
Vignette du fichier
PEER_stage2_10.1080%2F08927020701308315.pdf (1.32 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

hal-00526213 , version 1 (14-10-2010)

Identifiants

Citer

Veronique van Speybroeck, Karen Hemelsoet, Bert Minner, Guy B Marin, Michel Waroquier. Modeling elementary reactions in coke formation from first principles. Molecular Simulation, 2009, 33 (09-10), pp.879-887. ⟨10.1080/08927020701308315⟩. ⟨hal-00526213⟩

Collections

PEER
41 Consultations
490 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More