화학공학소재연구정보센터
Energy & Fuels, Vol.11, No.6, 1127-1136, 1997
Nonconventional Residuum Upgrading by Solvent Deasphalting and Fluid Catalytic Cracking
This work presents the deasphalting characteristics of nonconventional vacuum tower bottoms (VTB) from Athabasca oil sands bitumen and Lloydminster heavy oil. These materials were deasphalted using four solvents (propane, n-butane, n-pentane, and n-heptane) over a range of solvent/VTB ratios, temperatures, and pressures. The objective was to provide an experimental data base for assessing the applicability of deasphalting and catalytic cracking technology to nonconventional residuum upgrading. Sufficient data were collected from deasphalting experiments to develop ternary phase envelopes for the eight solvent-residuum systems and to establish the effects of solvent type and operating conditions on deasphalted oil (DAO) yield and quality. Deasphalting experiments were carried out in a single equilibrium cell and solvent-rich and lean phases were analyzed for oils, resins, and asphaltenes. The system was represented as a pseudoternary system where the resins could be combined with the oils or with the asphaltenes as asphalt. The deasphalting results showed that as the molecular weight of solvent decreased from n-heptane to propane, the DAO yield decreased while its quality improved : Conradson carbon residue (CCR), sulfur,nitrogen, and metals, as well as the density, decreased, and the oil content of DAO increased. Upon catalytic cracking at constant severity, product yields could be correlated with either oil or asphalt content of DAO. For a given composition of DAO, it was found that roughly 50% of oils and 20% of resins in DAO were converted to gasoline.