Partial upgrading of vacuum residue from Canadian oil sand bitumen under CO/H₂-H₂O

The upgrading of the vacuum residue from Canadian oil sand bitumen was performed in a batch reactor with the syngas (CO/H₂) and H₂O. The effect of CO/H₂-H₂O for residue upgrading was verified. In the presence of CO/H₂-H₂O, the coke induction period is postponed by 3.5-6.5 min. When the coke yield is about 0.1%, the viscosity reduction efficiency can be raised by 29.1% at 410℃ and even 54.6% at 420℃. The upgrading experiments were also carried out in the presence of N₂-H₂O, CO-H₂O, and H₂-H₂O, respectively. The results show that the capability to inhibit the coke formation was in the order of H₂-H₂O > CO/H₂-H₂O > CO-H₂O > N₂-H₂O. The impetus of CO/H₂-H₂O to BVR upgrading could be attributed to the active hydrogen mainly from H₂, nascent hydrogen by water-gas shift reaction as well as aqua-thermolysis. The thermal conditions such as the pressure of syngas, water content and reaction temperature could influence the coking propensity of BVR under CO/H₂-H₂O by affecting the three different attributions. These results indicate that the more accessible and low-cost syngas could provide the necessary hydrogen for BVR upgrading. Water presents a synergism with syngas for further promoting the BVR upgrading process.