Plenty Tank Cleaning Report
Continued From Previous Page

Comments on Laboratory Report

From the sludge depth measurements, the calculated volume of sludge is 10,320 Bbls.

Laboratory Analysis:

Comments:

1) Water: There seems no doubt that tank No. 1141 contained approximately 4000 Bbls. of water. The laboratory analysis indicated 4117 Bbls. and the test team calculated at least 3600 Bbls. of water was drained from the tank.

2) Sediment: The laboratory analysis indicated 3081 Bbls. compared with the final tank condition of 2907 Bbls.

i.e. Average of 3" of sediment on tank bottom		1407 Bbls.
Plus B.S. & W. in suspension 0.5% Vol.		1500 Bbls.
NOTE: The laboratory analysis of the	Total:	2907 Bbls.
final samples showed that there was no
water and, therefore, must be all sediment.

The sediment found in the sludge samples which was heavier than water remains a mystery. The laboratory were unable to identify it, except to say that it was not sand or a hydrocarbon.

During the mixer test many samples were analyzed for B.S. & W. content and this sediment was never mentioned again.

Therefore, for the purposes of this test it was treated just as sediment.

Also, the volume concerned (437 Bbls.) is small enough to be considered insignificant.

3) Oil: The laboratory analysis indicated 3122 Bbls. compared with 3296 Bbls. calculated

SUMMARY

These figures are remarkable in that they are so close, and therefore, can only be regarded as factual.

EQUIPMENT USED

Two Plenty swivel angle heavy duty side entry mixers model No. 31P-SVM-37

complete with Heemaf 37 K.W. type UK 225MGQ-4 electric motor suitable for

460 volts 3 phase 60 Hertz.

Mixer Serial No. 62596/M41/1-2

Motor Serial No. 77.126452/01-02

MIXER INSTALLATION

The mixers were removed from the packing crate and lifted in a horizontal position by a mobile crane to the tank manway.

Still in a horizontal position the mixer was then swung round towards the tank wall and one blade of the propeller introduced into the manway.

The mixer was then gently swung back towards the center and at the same time the propeller was rotated.

With the propeller now in, the mixer and tank manways were lined up and bolted together.

Both mixers were in the tank and bolted up ready for the tank to be filled within 1½ to 2 hours.

TEST PROCEDURE

Originally Tank No. 1141 was in BERRI service, but it was found when the tank was ready for filling that all Berri production was being shipped through Terminal North.

In view of this it was requested and agreed that Tank 1141 change service to Arabian Light.

The tank was duly filled with Arabian Light to a height of 44 feet 7 inches (300,00 Bbls.). After a period of 10 hours setting time the first samples were taken.

As the tank was not filled completely, the top sample point on the tank was above the roof and, therefore, it was not possible to take a top sample.

However, samples were taken from the bottom and middle sample lines, each time ensuring the lines were flushed before taking the actual samples.

SAMPLE ANALYSIS

As this analysis showed the oil to be only just within shipping specifications ( Maximum 0.2% Vol. B.S. & W. Maximum 10 PTB Salt ) it was decided to start one mixer only.

Taking into account the high water content indicated by the sludge analysis, the mixer nearest the tank outlet and drain valve was used at 30° to the right to direct the flow past the outlet and drain valve with a cleaning this area of the tank first.

This would allow any ' free' water to be drained off.