Study of catalytic cracking of asphaltene in near-critical water

摘要

The method of solvent division is adopted to separate asphaltene from Shengli heavy oil by n-heptane. ~1HNMR and ~(13)CNMR spectrum of asphaltene were determined with a Bruker Avance 400 NMR spectrometer. Combining with the elemental analysis results, the aromatic-ring structure is main structural composition in the asphaltene. Asphaltene was catalyzed and cracked with naphthenate nickel as catalytic cracking catalyst in near-critical water. The suitable reactional condition was obtained by orthogonal experiment method, reaction temperature 300°C, the mass fraction of catalyst used 0.6%, reaction time 24h. By testing element content of cracked asphaltene, carbon element content had reduced 0.06%~0.80%; hydrogen element content had reduced by 0.74%~3.41%; oxygen element content had reduced by 3.12%~27.1%; nitrogen element content had reduced by 0.40%~13.47%; sulfur element content had reduced by 9.85%~31.26%. As thin oil fields at later stage of mining, mining of heacy oil is being gradually focused. Heavy oil is rich in colloid and asphaltene. Due to its high viscosity, high density and poor liquidity, mining and gathering are more difficult than usual. The precipitation of high content of asphaltenes in Heavy oil will result in the congestion of pipelines and equipment. Because of high content Acidic functional group and active organic sulfur, the carbon steel pipe and equipment in the refinery will be eroded. FAN Hong-fu etc. researched and developed an new technology for mining heavy oil which is useing aquathermolysis. The effect of indoor experiment and oil field application is remarkable. Chen Eryue etc. studied the degradation of asphaltene coming from Liaohe heavy oil in the catalytic thermal cracking reaction, and the asphaltene in heavy oil can degrade about 20%. The catalytic cracking of asphaltene in near-critical water is being studied in this paper.