Study On Hydrogenation Pretreatment Process Of Waste Lubricating Oil Regeneration Suspension Bed

The year-on-year increase in global lubricant production and consumption has led to the generation of millions of tons of waste oil per year.Recycled waste lubricating oil can not only recycle non-renewable petroleum resources to a certain extent,but also effectively block the source of waste oil pollution and completely solve its environmental pollution problems.The traditional distillation method as the waste oil regeneration pretreatment process can not effectively remove the particulate matter and metal impurity elements in the waste oil,which is easy to poison the hydrotreating catalyst,and the direct distillation will bring the fouling blockage of the distillation device pipeline,so the research uses the suspended bed hydrogenation technology as a waste oil regeneration pretreatment process.Firstly,several kinds of dispersive catalysts,oil-soluble nickel,oil-soluble molybdenum and water-soluble molybdenum,were used to supercharge and depressurize the catalyst.The results show that the three catalysts have certain viscosity-reducing effects at 380°C,6 MPa and 1 h,and have the effect of inhibiting coke formation.Among them,the oil-soluble molybdenum catalyst has a higher base oil yield of about 80%-84%;the trace metal element in the product oil has an oil-soluble molybdenum catalyst superior to the oil-soluble nickel catalyst,and the optimized catalyst active metal addition amount is 600 ?g/ g,catalytic metal removal rate of 96.7%.Increasing the reaction conditions contributes to the removal of the metal,but causes problems such as heavy component coke formation and a decrease in the base oil yield.The composition and physical and chemical properties of the products under different reaction conditions were investigated by using a suspended bed hydrogenation unit and oil-soluble molybdenum as catalyst.After pretreatment,the basic properties of waste oil such as viscosity,density,ash,moisture,toluene insoluble is significantly reduced with increase of the temperature,catalyst content and time.The content of S and N in the oil decreased,and trace elements such as Cl,Si,Ca,Zn and P were almost completely removed.For the analysis of product composition,the cracking gas content increases with increasing temperature and reaction time,and the increase of catalyst addition can reduce the generation of cracking gas.The temperature has little effect on the changes of paraffins,naphthenes and aromatics in liquid products.As the catalyst content and time increase,the aromatic hydrocarbon content in the product oil decreases and the gum content decreases.The reaction conditions were optimized by the properties of the product: temperature 400° C,catalyst active metal addition amount 600 ?g/g,reaction time 90 min.Finally,the commercially available base oil was used as a research oil sample to examine the effects of temperature,pressure and catalyst.Under the low pressure hydrogen-free condition without catalyst,the product coke can not be inhibited as the reaction temperature increases.The rate of macromolecular condensation reaction is reduced after the addition of the catalyst.The partial pressure of hydrogen is increased,and the thermal cracking reaction can be further suppressed.When an additive is introduced into the base oil,the product base oil fraction is reduced,and the degree of hydrocracking in the reaction is deepened.The catalyst in the hydrothermal treatment of the suspended bed can effectively reduce the decomposition temperature of the lubricating oil additive.