(42o) Novel Solvent Recovery Method for Solvent Deasphalting Process
Recently, demand for crude oils has been increased but their reserves have been diminishing, leading to more attention toward unconventional oils. Unconventional oils account for 70% of total oil reserves but they cannot be easily utilized because of highly contained heteroatoms such as metal (V, Ni), nitrogen and sulfur, and their high viscosity causes transportation problem. Therefore, heavy oil upgrading processes are required for unconventional oil to be converted into light oils, and these processes can be categorized as carbon rejection and hydrogen addition. Solvent deasphalting (SDA) process is a carbon rejection process for heavy oil upgrading in which solvents (C3-C7) extract asphaltene-removed light components that are called deasphalted oil (DAO) and alkane-insoluble component, asphaltene, is enriched in the bottom of extractor. In SDA process, required amount of solvent is normally four to ten times higher than that of heavy oil feed, which makes solvent recovery process important to save operating cost. Conventional solvent recovery process is operated in supercritical conditions of solvent, obtaining phase separation between DAO and solvent, and high temperature and pressure are required, resulting in high energy consumption. In this study, novel solvent recovery process is proposed, which can separate solvent selectively from DAO using supercritical CO2 (Sc-CO2). The results show that at moderate pressure (<100 bar) and temperature (<60 °C), solvent recovery reaches over 80%, indicating the possibility of alternative solvent recovery process.