Chapter 5
speed of the turbine was 3600 rpm, and the mixing time was 10 min at desired
temperature. The initial pH of brine was measured with a pH meter without
contacting with diluted bitumen. The equilibrium pH of brine was measured with
pH test paper when the brine reached equilibrium with diluted bitumen.
5.3. Emulsion coalescence and clean oil separation
5.3.1. Methods
To find optimal demulsifier, 200 ppm demulsifier PRi - PR6 (based on the total
volume of the emulsion sample) was added to the emulsion samples immediately
after emulsion preparation. Aftenzvards, all the samples were shaken by hand at
the same time for 1 minute and then stored at 50 0C. The photographs and
photomicrographs of the samples were taken at ambient temperature shortly after
removing samples from the oven. After photography, the samples were put back
into the oven for storage.
To study the effect of pH and silicate, NaOH or Na2SiO3 was added to the
aqueous phase to change the pH before emulsion preparation. 200 ppm optimal
demulsifier is added to the emulsion samples immediately after emulsion
preparation. Sample 1 was prepared as control without silicate. The initial pH (I.
pH) ofthe brine measured by pH meter was 8.3. The equilibrium pH (E. pH) of the
brine separated from the emulsion after addition of PR5 was 8.0, which was
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