Fundamental Study On Thermal Processing Of Oil Sands Bitumen With Hydrogen Donor

Unconventional crude oils are typically inferior in fluidity,ultra-viscosity,high asphaltene and metal content,and have brought great challenges to exploitation,transportation and processing.It is necessary to efficiently upgrade these high viscous crude oils for improving the processes.Thermal upgrading in the presence of hydrogen donors is one of good technologies for markedly decreasing the viscosities of these kind crudes.In this paper,fundamental study on technical adaptability,hydrogen donor selection and the performance of additives in the thermal processing of oil sands bitumen was carried out,aiming at laying the basis for the development of hydrogen-donated thermal upgrading process for bitumen.Distillation and systematic evaluation of oil sands bitumen were carried out first,and the thermal conversion of VR(bitumen vacuum residua with boiling ranges of 420 oC+)was then investigated in detail.The hydrogen donors were screened by the modified chemical probe method,and the relationship between upgrading effects and relative hydrogen donating ability was further investigated,on the basis of which the optimum thermal processing conditions were determined.Meanwhile,the upgrading effects of thermal conversion of Liaohe ultra-heavy oil were researched as confirmation.On this basis,the influence of PET-370,PET-380 and PET-395 on upgrading effects was also examined.Specific results were as follows: 1)The presence of HDB with high relative hydrogen donating ability in the thermal conversion of VR could effectively decrease the viscosity and density of visbroken oils,and increase the yields of high-valued products;2)With coke induction time as turning point,the viscosity and density of products reduced sharply first,then decreased smoothly even come to the trend of increscence with the reaction time,stability of visbroken oil also decreased;3)the optimum reaction condition of VR with distillate HDB(5 wt%)as hydrogen donor was 420 oC,10 min;4)Liaohe ultra-heavy oil with distillate DA(5 wt%)could been processed at 425 oC,30 min and if the mass ratio of DA increased to 10 wt%,the reaction condition of 428 oC,30 min would be reasonable.Three additives investigated in this paper have inhibition effects on asphaltene precipitation to different degrees,among which the inhibition rate of PET-395 was up to 33.8%,the optimal additive proportion was 200 ?g/g.The effective reaction time of PET-395 at 410 oC,420 oC and 425 oC was 21 min,15 min and 7 min,respectively.HDB and PET-395 were synergetic on inhibition of coke yields,the addition of hydrogen donors and additives would improve reaction severity and further contribute to better upgrading effects while the stability of upgraded oils was ensured.