conventional dispersants under Japanese effectiveness test standard called Hakusa 52,
2.1 Summary of Japanese effectiveness test standard
In order to conduct Japan's effectiveness test standard, 2ml of pre-mixed oil with
dispersant is added into each of two ,100-me separatory funnels containing 50 of sea water
each. Next, the separatory funnels are placed in a vertical shaker which shakes the
separatory funnels vertically ~t a rate of 300 reciprocations per minute at 40mm of
amplitude. The shaker is run for 5 minutes.(Photo l)
The separatory funnels are set on the shaker and the contents of one of them is allowed
to stand undisturbed for 30 seconds. The other funnel is allowed to stand undisturbed for
10 minutes before running off 30ml of the oily water through the taps into beakers.
Next, an extraction procedure is conducted with carbon tetrachloride. The absorbance of
the extract is measured against a carbon tetrachloride blank at a wavelength of 650nth.
Dispersion rate of the approval dispersants must be more than 6096 for the test funnel
after a settling time of 30 seconds and more than 20% for the test funnel after a settling
time of 10 minutes.
Photo I A seperstory funnel on a vertical shaker
2.2 Oil used in the tests
Heavy fuel oils(bunkerC) was used for the tests. The properties of the oil is given in
Table 1.
Viscosity of the oils corresponding to 201C and 501C were measured with a capillary
viscosimeter and viscosity of the oils corresponding to 100~C were measured with an
automatic viscosimeter. Relation between viscosity and temperature on the oil' is given in
Fig.1. Besides, viscosity of the oil C corresponding only to 20℃ was measured.
Table 1 Properties of the heavy fuel oil
| oil |
A |
B |
C |
| specific Gravity(15℃）g/c? |
0.951 |
0.956 |
0.972 |
| Flashu Point
℃ |
123 |
106 |
96 |
| Viscosity(cSt) |
at 20℃ |
800 |
1600 |
2700 |
| at 50℃ |
116 |
195 |
- |
| at 100℃ |
17 |
24 |
- |
| Pour Point
℃ |
0 |
-5.0 |
2.5 |
| Carbon Residue
wt% |
10.2 |
12.3 |
15.3 |
| Total Sulfur
wt% |
2.43 |
2.84 |
2.84 |
| Total Ash
wt% |
0.02 |
0.02 |
0.02 |
Fig 1 Relation between viscosity and temperature
2.3 Dispersants used
Two conventional dispersants currently available in Japan were used. These physical
properties are given in Table 2.
Table 2 Properties or two conventional dispersants
| |
Dispersant W |
Dispersant X |
| Liquid Nature |
colourless |
Light brown |
| Specific Gravity(15℃) |
0.793(20℃） |
0.853 |
| Flash Point(℃) |
94 |
106 |
| Viscosity（cSt/30℃） |
3.93 |
11.0 |
| Biodegradability（%） |
99 |
100 |
| Toxicity |
Skefetonema costatum(ppm) |
180 |
>100 |
| Killfish(TLm24,ppm) |
>24.000 |
14.500 |
2.4 Tests result
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