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ABSTRACT
The chemical compositions of, and structural types in, vacuum residues from Daqing, Shengli, Renqiu and Linpan crude oil vacuum residues were investigated. The residues were separated into six fractions by use of normal pentane precipitation and liquid adsorption chromatography using alumina containing 5% water as adsorbent. The nitrogen and nickel distributions in every fraction were then observed. The removal of nickel, nitrogen and residual carbon with the liquid chromatography separation techniques are comparable with the solvent deasphalting pilot plant data. The structural parameters were calculated with modified Brown-Ladner's method on the basis of elementary analysis, molecular weight determination and 1H-NMR spectroscopy, the results obtained show that the six fractions are obviously different in their chemical compositions and structures.