Chapter 5
Based on comparison of the five samples, increasing pH only cannot
separate oil from clay solids. Shaking only can offer external energy and separate
part of the oil from clay solids, but the skins of clay solids do not completely
disappear. A combination of increasing pH and shaking can separate the oil from
clay solids and destroy all the skins. After removing top clean oil layer, increasing
the pH of emulsion samples using NaOH or Na2SiO3 (samples 10 and 11) have
similar separation results. So increasing the pH to 8.8 with shaking is a good
method for the separation of clay solids.
5.5. Separation of oil-in-water emulsion (effects of pH)
5.5.1. Methods
30 ml of an oil-in-water diluted bitumen emulsion was prepared with 20 vol.%
diluted bitumen and 80 vol.% synthetic brine. 200 ppm PR5 was added to the
diluted bitumen before emulsion preparation. 1x104 M silicate and 2x10'4 M
NaOH were added to synthetic brine to increase the initial pH to 8.8. Then the
emulsion sample was formed by shaking the bottle for 1 minute at ambient
temperature. Several drops of 1.0 M HCI were added to the samples immediately
after emulsion preparation. The samples were put into the oven at 50 0C. The pH
was measured by pH paper when the system reached equilibrium.
Slides were prepared by sampling from different positions of emulsion
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