The name is absent

Chapter 5

This experiment shows that the oil-in-water emulsion can be broken at a low
pH level, i.e. 5.0 or lower. Study of interfacial properties of emulsified bitumen
droplets also shows that bitumen drops are unstable at low pH ^t9j. When the pH is
low enough, all the soap will form naphthenic acid. The system will prefer to form
a water-in-oil emulsion. But because the oil layer contains demulsifier PR₅,
water-in-oil emulsions are not stable in the absence of clay solids. Thus clean oil
and bulk water layers can be obtained.

5.6. Three-step separation Ofdiluted bitumen emulsion

5.6.1. Methods

Afterfinding the optimal separation conditions in each step (section 5.3 - 5.5),
the entire three-step procedure was performed. 60 ml water-in-oil diluted bitumen
emulsion was prepared with 50 vol.% diluted bitumen and 50 vol.% synthetic
brine with 1x10'⁴ M silicate at 50 ⁰C, as described in section 5.2. 200 ppm PR₅
was added to 30 ml emulsion sample immediately after preparation. The clean oil
Iayerwas removed 24 h after emulsion preparation. 2x10^⁴ M NaOH was added to
aqueous phase to increase the initial pH to 8.8 with shaking. The emulsion layer
and solids layer were separated 24 hours later. Atotal of 0.15ml 1.0 M HCI was
added to the emulsion Iayerto Iowerthe equilibrium pH to 5.0. Photographs of the
separation were taken 24 hours later.

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