UBC Theses and Dissertations
A study of heavy oil ultrafiltration using ceramic membranes Duong, Anna Manhoa
Heavy oil refining is complicated by the presence of relatively high concentrations of contaminants that include sulfur, nitrogen, heavy crude components (asphaltenes) and heavy metals such as nickel and vanadium. The heavy crude components lead to coke formation and the metals deactivate catalysts irreversibly during hydroprocessing. In the present study, the feasibility of heavy oil ultrafiltration using ceramic membranes to remove the problematic asphaltenic components has been examined. The study was divided into two parts: an experimental study and a modeling study of membrane fouling. A number of experiments were conducted to examine the effect of membrane pore size, crossflow velocity and membrane regeneration on the permeate flux and asphaltene reduction. Results from the experiments showed that both the flux and the asphaltene concentration of the permeate declined with time due to membrane pore restriction. For example, with a O.lfim nominal pore size membrane operating at 110°C, 600kPa and a cross-flow velocity of 6.9m/s, a flux of 55 kg/m2/day and an asphaltene reduction of 80wt% were obtained after 9 hours on stream. Permeate flux increased with increased cross-flow velocity and membrane pore size whereas asphaltene reduction increased with decreasing membrane pore size. A number of correlations were obtained for the viscosity, density, vanadium and nickel content versus asphaltene content in heavy oil.
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