Dynamic surface tensions of Athabasca bitumen vacuum residue including the effect of dissolved air

The pendant drop technique was used to measure the equilibrium and dynamic surface tensions of Athabasca bitumen vacuum residue (500 °C+) (AVR) between 150 and 280 °C. A significant (16%) slow (over hours) decrease from initial to equilibrium values was found. In addition, the effect of dissolved air on surface tension was studied at 150 °C by comparing dynamic surface tensions of air- or nitrogen-saturated AVR in contact with air or nitrogen. It was found that the presence of dissolved air significantly decreases the dynamic change in surface tension (from 16 to 5%). In order to perform the surface tension studies, the density of AVR was required. Archimedes method was used to measure the density of AVR from 98 to 335.8 °C.