Catalytic Cracking Of Asphaltene In Near-critical Water

The method of solvent division is adopted to separate asphaltene from four kinds of oil sample from Shengli Oilfield by n-heptane. ¹H and ¹³C NMR spectrum of asphaltene were determined with a Bruker Avance 400 NMR spectrometer. By combining the infrared spectrum and the elemental analysis results, the mass fraction of carbon and hydrongen elements reach 91%⁹4%, the contents of oxygen, nitrogen and sulphur elements are 5%⁸%. There is the aromatic-ring structure in the four kinds of asphaltene. The four kinds of asphaltene contain N-H, cycloalkane, C-H of alkane and -CH₂-.Asphaltene was catalyzed and cracked with naphthenate nickel and naphthenate ferrous as catalytic cracking catalyst in near-critical water. The reaction temperature, reaction time and the amount of catalyst are investigated influence of the conversion rate of asphaltene respectively by orthogonal experiment method, the same time, the suitable reaction conditions were obtained.The elemental analysis is carried out on cracked asphaltene respectively, then analyze the element composition of the asphaltene before and after reacted, and calculate the conversion rate of asphaltene. Through analysis, sulphur element contents had reduced Obviously on the cracked asphaltene. The contents of carbon , hydrongen,oxygen and nitrogen elements also had reduced differently.The cracked asphaltene was determined by infrared spectrum, then results of the aspphaltene before and after reacted were analyzed. Through analysis, cycloalkane, C-H of alkane and -CH₂- had broken in the cracked asphaltene, the fragrant ring number had falling off.Through comparison of the four kinds of cracked asphaltene in the system of near-critical water with catalyst and without catalyst. We can know that naphthenate nickel and naphthenate ferrous have better results on catalytic cracking of asphaltene in the system of near-critical water.