Study On Regeneration Process Of Waste Lubricating Oil By Molecular Distillation And Flocculation

Waste lubricating oil was not only a kind of poisonous pollutant, which harmed the natural balance and environmental health, but also was valuable petroleum resource. With the development of social economic and increasing environmental awareness, regenerative technology of waste lubricating oil became the focus of current global scientific research. In spite of the increasing scale, outdated regenerative technology, low out- put regenerative oil, severe secondary pollution were still the major problems of the domestic regenerative oil industry. The research of new green regenerative technology of waste lubricating oil, which has simple program, low energy consumption and ideal regenerative effect, could promote the revolution of domestic regenerative oil industry and the development of circular economy. Based on the development of domestic regenerative oil industry and researches on the regenerative technology of waste lubricating oil, this article respectively investigated the processing feature and processing effect of molecular distillation and flocculation. And it proposed a combined regenerative route for waste lubricating oil, which combined the molecular distillation and flocculation. The research results were showed as follows.(1) The temperature, pressure and feed flow had major impact on the function indicators of regenerative oil, which came from the molecular distillation. With the growth of temperature, the value of function indicators, such as chroma, kinematic viscosity, carbon residue and acid number were all variously increased. With the growth of pressure, the value of function indicators, such as chroma, kinematic viscosity, carbon residue and acid number were all variously decreased. With the growth of feed flow, the value of function indicators, such as chroma, kinematic viscosity, carbon residue and acid number were all variously increased. Regenerated oil, which obtained in different condition, had distinct different quality. Meanwhile, the temperature had more significant influence on the function indicators of regenerative oil, followed by the pressure. The influence of the feed flow was relatively weakest.(2) The compound flocculants for the regenerative oil of molecular distillation were obtained by blending inorganic flocculants with organic flocculants. The ingredient of the compound flocculants, which obtained by selected experiments, was as follows: the mass ratio between the triethylene tetramine(TETA) and Potassium hydroxide(KOH) was 1:3. For the regenerated oil of molecular distillation, the optimal applied condition of the flocculants were as follows: flocculants dosage of 6%, reaction temperature of 60℃, stirring speed of 800 r/min, constant temperature of 80℃, and settling time of 24 hours. On that condition, with the compound flocculants, the transmittance of the regenerated oil was 89.23%, which increased 56.58% compared to the previous oil.(3) It could be found that, as the pivotal operation parameters in the molecular distillation-flocculation combined process, the temperature of molecular distillation had max effect on the transmittance of the regenerative oil, followed by the flocculants dosage, flocculation reaction temperature. The influence of the pressure of molecular distillation was relatively weak.The optimal controlling conditions for the molecular distillation-flocculation combined process were obtained by orthogonal optimization experiments.The results were showed as follows: the temperature of molecular distillation of 210℃, flocculants dosage of 6%, reaction temperature of 60℃, the pressure of molecular distillation of 70 Pa. On that condition, the regenerative effect of waste lubricating oil was notable and the transmittance of the regenerated oil was 91.36%. And, sectional function index of the regenerated oil can meet or exceed the standard of base oil HVI-200. The molecular distillation-flocculation combined regeneration process was relatively practical and environmental, which can achieve relatively notable regenerative effect.