Physical Properties and Rheological Characteristics of Deasphalted Oil Produced From a Solvent Deasphalting Process

Because of conventional oil being-exhausted and its increasing price, the technologies to use unconventional oil and low value crude residues, which have not been fully exploited, are receiving more and more interest. Unconventional oil contains a lot of asphaltene which hinders utilizability of unconventional oil. As the asphaltene has high viscosity and contains large amounts of heavy metals, it decreases the fluidity of oil and causes catalyst poisoning. Furthermore, the process of desulfurization and denitrification are necessary to use unconventional oil because the asphaltene has a high sulfur and nitrogen content. As the unconventional oil has these drawbacks, an extraction process called solvent deasphalting is commonly used to acquire deasphalted oil(DAO) through the removal of asphaltene. The DAO is generally used for lube base oil, and besides, it is converted into transportation fuel and chemical raw materials by additional refinement. In this study, the physical properties and rheological characteristics of DAO were measured for more efficient utilization of DAO. Pentane and hexane were added into DAO to investigate the effect of the solvents on the viscosity of DAO solution. As the content of pentane and hexane was increased, the viscosity of DAO was decreased, resulting in the improved fluidity of DAO. The degree of decreasing rate in viscosity was declined with increasing amount of solvent. The viscosity of DAO was characterized using a rheometer under various temperature conditions to investigate the effect of temperature on the fluidity. The fluidity of DAO was rapidly increased with increasing temperature and the DAO showed the behavior of a Newtonian fluid above 70 ^OC, which is called the softening point. Additionally, the fluid behavior of DAO in a pipe was simulated using computer softwares, GAMBIT and FLUENT. The velocity profile of DAO in a pipe was rapidly changed around the softening point.