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Stabilité thermique de la fraction aromatique de l'huile brute Safaniya (Moyen Orient) : étude expérimentale, schéma cinétique par classes moléculaires et implications géochimiques

Abstract : The thermal evolution of reservoired oils is controlled by the kinetics of cracking reactions. The present work is concerned with the study of the thermal stability of the light aromatic components (C6-C14) of crude oils under geological conditions. The aim is to predict this stability through a model derived from laboratory pyrolyses. The light cut <250 °C of Safaniya crude oil, corresponding to the C15- components, was obtained by fractionated distillation; pure aromatic fraction was then separated by liquid chromatography. Detailed molecular characterisation of the aromatic fraction was acquired using HPLC, GC and GC/MS. Then, quantified individual aromatic compounds were lumped into six molecular classes: BTXN, methylaromatics, alkylaromatics, naphthenoaromatics, indenes and sulphur-containing aromatics. Pyrolyses of the aromatic fraction were performed in gold tubes at 100 bars and different temperature/time conditions in a wide range (1 to 93%) of global conversion. Pyrolysis effluents were analysed and lumped into classes. The pyrolysis data were used to elaborate a semi-empirical kinetic scheme of 13 stoichiometric reactions for the primary and secondary cracking of the unstable classes. The scheme kinetic parameters were first estimated, and then numerically optimised, with the constraints of mass balance and hydrogen conservation. A set of pyrolysis experiments was performed at 375 °C under high pressures: 400, 800 and 1200 bars. Increasing slowing down in conversion rate with increasing pressure was thus observed compared to experiments at 100 bars. A slight selective effect of pressure on the different aromatic classes of the charge and on the product distribution was evidenced. The extrapolation of the kinetic model to the conditions of Elgin Field (North Sea) showed that pressure effect should shift the thermal cracking of light aromatics to higher temperatures by almost 8 °C.
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https://pastel.archives-ouvertes.fr/pastel-00001352
Contributor : Ecole Chimie Paristech <>
Submitted on : Friday, September 10, 2010 - 3:55:56 PM
Last modification on : Wednesday, October 14, 2020 - 3:57:59 AM
Long-term archiving on: : Friday, September 10, 2010 - 4:19:16 PM

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  • HAL Id : pastel-00001352, version 1
  • PRODINRA : 246366

Citation

Tammam Al Darouich. Stabilité thermique de la fraction aromatique de l'huile brute Safaniya (Moyen Orient) : étude expérimentale, schéma cinétique par classes moléculaires et implications géochimiques. Chimie. Chimie ParisTech, 2005. Français. ⟨pastel-00001352⟩

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