Low Frequency Vibration Assisted Catalytic Aquathermolysis of Heavy Crude Oil

Abstract

Low frequency vibration was applied to assist the catalytic aquathermolysis reaction of heavy oil for the first time. The optimum vibration parameters were first optimized by orthogonal experiments: vibration acceleration is 3 m·s^–2, vibration time is 90 min, and vibration frequency is 20 Hz, and the efficient consequences of the parameters are as follows: vibration acceleration > vibration time > vibration frequency. Under the optimum vibration parameters, heavy oil viscosity could be reduced by 88.2% after reaction, and the viscosity bounce rate of treated oil is 4.9%. To evaluate the vibration’s performance, the structure and group compositions of the oil before and after reaction were characterized by modern chemical analysis techniques, such as column chromatography, elemental analysis, gas chromatography, and Fourier transform infrared spectrometery. It is found that vibration cannot initiate new reactions in the process of catalytic aquathermolysis, but it can promote the original reactions and deepen the reaction degree such as dealcoholization reaction, hydrogenation reaction, ring-opening reaction, and alkyl side chain removal reaction, etc. Compared to catalytic aquathermolysis reaction, vibration assisted catalytic aquathermolysis can further decrease the average molecular weight of heavy oil, increase the saturate and aromatic contents, decrease the resin and asphaltene contents, improve the ratio of <i>N</i>_H/<i>N</i>_C, and decrease the heteroatoms content of heavy oil. Vibration plays more important role in the in situ catalytic aquathermolysis reactions due to the fact that vibration could aid to reduce the adsorption of catalyst and help the catalysts contact with heavy oil sufficiently in the porous media. The preliminary results proved that the vibration assisted in situ catalytic aquathermolysis technique is feasible and it has some practical value