Chemical Tankers / Day 3 / Day 3 Topic 5 Tank Cleaning Guidelines

5.3 Industry best practice in tank cleaning

Hydrocarbon mixtures, Lubricating Oils

If cleaning stainless steel, zinc or epoxy tanks and subsequent cargo requires very clean tanks, spraying with degreaser before commencing of the initial washing should be considered.

5.3 Industry best practice in tank cleaning

Hydrocarbon mixtures, Lubricating Oils

Wash with ambient temperature water for 3 cycles (injection with degreaser may be used), followed by hot water (80C) for 4 hours. Recirculation with Caustic, Butyl Cellosolve or hand spraying with Butyl Cellosolve may be required.

5.3 Industry best practice in tank cleaning

Waxes

At the completion of discharge the tanks must be confirmed well stripped/empty. Any cleaning at sea should be carried out in full & strict compliance with MARPOL Annex II because the residues of these cargoes will float on the water surface.

5.3 Industry best practice in tank cleaning

Waxes

In all tank linings, the initial wash should be at the discharge temperature of the wax for 3 cycles, followed by hot (maximum temperature) water for at least 4 hours. If there is persistent residual odour, then re-circulation with odour removal, for example P3 NA Marine will assist.

5.3 Industry best practice in tank cleaning

Acrylates

The main difficulties in cleaning of Acrylates involve the removal of odor and problems with low PTT (due to Inhibitor presence) when cleaning to a wall wash standard.

The washing of Acrylates should always started with ambient

temperature.

5.3 Industry best practice in tank cleaning

Acrylates

In stainless steel tanks start with ambient temperature for 3 cycles, followed by hot for 2 hours. Odor can be removed by spraying with 1-2% Bleach solution, washed off immediately and completely with fresh water or re-circulation with P3 NA Marine odor removal. This will also assist with PTT increasing.

5.3 Industry best practice in tank cleaning

Acrylates

In epoxy tanks, a reference to Resistance Guidelines will indicate if there is a likelihood of softening of the coating. Wash with ambient water for 3 cycles, followed by hot water for 3 hours. If odor is still present, re-circulate with odor removal P3 NA Marine or hand-spray with Butyl Cellosolve followed by hot wash.

5.3 Industry best practice in tank cleaning

Practical Exercise.

End of Topic