DYNAMIC CHANGE OF ASPHALTENE MICROSTRUCTURE DURING RESIDUE SLURRY-BED HYDROCRACKING

Abstract

Abstract: In order to study the dynamic changes of asphaltene microstructure during residue hydrogenation, Karamay atmospheric residue was used as raw oil for slurry bed hydrocracking reaction with different reaction time. The asphaltenes in reaction products were separated, and their basic properties and coke yield were analyzed. The asphaltenes were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). The results suggested that the residue hydrocracking in slurry-bed could be divided into two reaction stages according to the change of asphaltenes microstructure. During the reaction time less than 20 min, the asphaltene content gradually increased, the surface changed from smooth to rough, and three-dimensional accumulation of particles appeared. The accumulation of aromatic lamellae tended to ordering changes, the number of layers increased gradually, and the interlayer spacing and alkyl side chain spacing decreased continuously. After the reaction time of 20 min, the asphaltenes converted to coke fast and the content of asphaltenes decreased significantly. The stacking of aromatic layers changed disorderly and the number of aromatic layers decreased, the spacing between aromatic layers and the spacing between alkyl side chains increased gradually.

Key words: asphaltenes, coking rate, microstructure, stacking of particles, stacking of aromatic layers

References

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