Upgrading Of Oil Sand Bitumen For Viscosity Reduction By Supercritical Hydrothermal

Heavy oil,which accounts for two-thirds of the world’s total oil reserves,can alleviate the current energy crisis in the world,if it will be processed and utilized effectively.The supercritical water was used to modify the heavy oil,and the optimum conditions for supercritical hydrothermal upgrading of oil sand asphalt were explored.Corncob was selected as hydrogen donor in our upgrading system,and supercritical hydrothermal co-upgrading experiments of oil sand bitumen and corncob were carried out to verify the co-upgrading effects and to explore the synergistic effects of co-upgrading.First,the tubular reactor was improved.Adding the drive devices into reaction system to strengthen the mixing of materials in the reactor,and adding reactor accessories(asphalt bag and pressure-resistant liquid tank)to increase the accuracy of raw material addition and product extraction.It was found that the optimum reaction temperature was 390 °C,the optimum mass ratio of water to oil which were added into reactor was 1:1,the number of reaction stages was 3 and single reaction time was 15 min,the stirring rate was 30 r/min.As results,the viscosity of the modified product was 360 c P,the bromine value was 24.32 g Br/100 gsample,the coking rate of the system was 0.07 wt%,and the removal effects of sulfur,nitrogen,nickel and vanadium were 51.8%,57.9%,79.2% and 21.2%,respectively.It was found that the higher molecular weight of organic molecule is,the more difficult to diffuse to supercritical water phase for it.In the process of supercritical hydrothermal upgrading of heavy oil,oil phase and water phase will diffuse to each other,and the rate of water molecule diffusing to organic phase is faster than that of organic molecule to water phase.Through supercritical hydrothermal co-upgrading of oil sands bitumen and corncorb,the upgrading temperature of oil sands bitumen decreased,the viscosity of the modified product can be reduced to 37 c P,the bromine value was 18.93 g Br/100 gsample,the removal rates of Ni and V were 85.3% and 56.3%,respectively.At the conditions of the mass rate of oil sands bitumen: biomass: water was 8:2:10,reaction temperature was 400 C,stirring rate was 30 r/min and reaction time was 40 min.At the same time,carbohydrates,carboxylic acids,alcohols and otheroxygen-containing compounds produced by biomass pyrolysis will continue to pyrolysis or dehydration under such conditions,resulting in the reduction of oxygen content from 35.15% of biomass oil to 4.58% of co-pyrolysis products.