Chapter 5
5.4. Clay solids separation from rag layer (effects of pH and shaking)
In this section we show that a second step of the separation involving
increasing pH of the system can emulsify the oil to form an oil-in-water emulsion
and separate oil from clay solids.
5.4.1. Methods
Emulsion samples were prepared with silicate at initial pH 8.5. 200 ppm
demulsifier PR5 was added to the emulsion samples immediately after preparation.
Top clean oil layer was removed 24 hours after adding PR5. After separating the
clean oil layer, five samples were prepared then stored at 50 0C. Samples 7 -11
were prepared as shown in Table 5.2. Photographs were taken 24 hours later.
Table 5.2 Emulsion samples with 200 ppm PR5 and different alkali at different pH
after removing top clean oil layer
|
Sample |
Na2SiO3 |
NaOH |
Shaking |
Initial pH |
Equilibrium pH |
|
7 |
I |
I |
without |
8.5 |
8.0-8.5 |
|
8 |
I |
2.0x10'4 M |
without |
8.8 |
8.5 |
|
9 |
I |
I |
with |
8.5 |
8.0-8.5 |
|
10 |
I |
2.0x10'4 M |
with |
8.8 |
8.5 |
|
11 |
1.0x10^4M |
I |
with |
8.8 |
8.5 |
Slides were prepared by sampling from different positions of emulsion
samples for making microscopy observations. In the observation of clay solids
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