Asphaltene Adsorption from Hydroconverted Bottoms

Abstract

The adsorption of asphaltenes from hydroconverted bottoms (HCB) was evaluated using the Asphaltene Determinator to quantify the amount of asphaltenes removed, track the changes in the asphaltene solubility profile, and gauge the selectivity of removing the most aromatic asphaltenes as judged by the 500 nm Coke Index. Adsorption onto a variety of silica gel sorbents was investigated to determine the importance of surface area relative to pore diameter and pore volume. The adsorption behavior of HCB was compared with that of unprocessed bitumen from the Peace River area (PRFR), which contains significantly larger asphaltenes that were more sensitive to sorbent pore properties. Additionally, the optimum adsorption temperature for the unprocessed PRFR asphaltenes was much higher than that for HCB asphaltenes. Adsorption of asphaltenes from HCB improved the quality of the oil by significantly reducing its viscosity, increasing the H/C ratio, decreasing the nitrogen and total basic nitrogen, increasing the P value, removing precoke-type asphaltenes, and reducing Ni and V.