Due to constantly growing environmental awareness and the resulting obligation to protect the world around us (in this case the water) against pollution, a countless variety of barriers have been developed.
Most of these barriers consist of floating booms which contain oil and floating debris within their sub-surface portion (the skirt).
During an emergency situation where the floating boom has to be transported to the place of need, generally there is no alternative to a floating boom. However, for the protection of permanent installations, such as harbour entrances, tanker berths and water intakes, pneumatic oil barriers are an alternative with many advantages over conventional floating booms.
Pneumatic oil barriers
The pneumatic oil barrier generates a current on the water’s surface with sufficient velocity to stop oil from overrunning it. The current is produced by rising air bubbles which cause an upward water flow. When this vertical flow reaches the surface of the water it divides into two horizontal currents which flow away from the vertical stream of bubbles (see Figure 1).
The air for the bubbles is distributed along the barrier line by special nozzle pipes which are placed on the seabed. A compressor station located on the shore generates the compressed air for the pneumatic oil (bubble) barrier. The service pressure generated by the compressor station has to be higher than the hydrostatic pressure of the water.
During extensive practical tests carried out by the University of Hannover, the results showed that compressed air systems can retain thick oil layers.
The following products were retained during the tests:
• 52 mm petrol
• 70 mm gas oil
• 85 mm raw oil
• 167 mm machine oil
To ensure that the barrier will meet its purpose…
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