Washing of Tanks and Pipe Lines on Chemichal Tankers

Abstract

This is to report on the results of the tank and pipe line washing experiment carried out on small chemical tanker of Japan in its actual operation.
In the period from January to March 1994, after-discharge washing tests were carried out on a small chemical tanker which had carried Alpha-Methylstyrene and m-Disopropylbenzene. At this time, freshwater washing by using washing machine was conducted at the prescribed number of cycles. Wash water was accomodated in the slop tank through a discharge line and the amount of the wash water was mesured. Samples of this wash water were taken at the manifold in the couse of transfer to the slop tank and the times of sampling were recorded by a stop watch. Concentration of the residual substances in the wash water was mesured in the laboratory and the relation between the amount of the wash water and the residual concentration was graphically shown at every passage of time.
In the tests, the required wash procedure was accomplished using a smalll amount of water that calculated by the formular in the International Maritime Organization P & A standard.
Using these results, the required average amount of wash water is estimated in the case of the small chemical tankers.
In order to decrease the required amount of washwater, it is necessary to decrease the dead spaces in the pipe lines during the washing.