Study On Visbreaking Of Liaohe Heavy Oil With Catalyst

Taking liao he heavy oil as object, the feasibility of aqua-thermolysis visbreaking at low temperature (180℃-300℃), the effects of reaction temperature, reaction time, and water content on the viscosity, composition, and average molecular weight of heavy oil were studied in detail. For further promoting aqua-thermolysis of heavy oil, based on the feasibility of aqua-thermolysis, catalyst for aqua-thermolysis of heavy oil was optimized, the influence on aqua-thermolysis of heavy oil of reaction condition, hydrogen donor and solvent was also investigated.The result show that when no catalyst was added, aqua-thermolysis of heavy oil can take place in the presence of water. The optimized reaction condition is 240℃for temperature, 24hrs for time and 20wt% for water content. Compared to no water existing in reaction system, the viscosity reduction rate of heavy oil was improved, when 20wt% water was added into reaction system. The amount of saturate and aromatic increases, and that of resin and asphaltene decreases, It's average molecular weight and density also decrease. When catalyst was added into the reaction system, aqua-thermolysis was promoted. NiSO4 was the best catalyst in the series of catalysts used in the experiments. Compared to no catalyst, adding NiSO4 0.1wt% in reaction system can increase viscosity reduction rate by about 30%. The combination of tetralin and solvent has a synergetic function to the reaction, adding 5wt% tetralin into reaction system can improve heavy oil viscosity reduction rate 6.3%, adding 8wt% tetralin can increase viscosity reduced rate 8.4%. Methanol as solvent of catalyst is also conducive to aqua-thermolysis, improving the quality of heavy oil.In summary, aqua-thermolysis of heavy oil is feasible and it is an economic way to improve the quality of heavy oil.