Closed loop scrubber system


The closed loop system uses seawater to wash the sulphur content of the exhaust gasses to an equivalent of 0,1%. In compliance with IMO regulations Seawater used in the process is continuously re-circulated.

Closed loop systems are primarily used for vessels that operate in ports and sailing areas where overboard discharge is prohibited.

Working principle

1. Exhaust gasses enter via the bottom side of the scrubber tower
2. Seawater is inserted at the top of the scrubber through spraying nozzles
3. This results in an equally divided spray pattern throughout the scrubber
4. Sulphur particles in the exhaust gas attach to the water droplets under the right temperature and process conditions
5. Process water is led to the circulation tank
6. NaOH is added to the process water to neutralize acidity
7. Cleaned process water is pumped upwards again to the top
8. Polluted water is drained and led through a separator
9. Solids and oil are removed from the polluted water forming sludge
10. Sludge is pumped to the sludge storage tank on the ship

*pH, turbidity and PAH are continuously monitored in accordance with IMO regulations, MARPOL Annex VI resolution MEPC.259 (68)

We were intrigued by the simplicity of the VDL AEC scrubbing system.
Their technology works without filters.
There is no pollution on the deck, no filters to clean and no maintenance.
After testing the VDL AEC Maritime closed loop scrubber on the Schleswig-Holstein
we were so convinced, we ordered scrubbing systems for three more vessels.

Fini Alsted Hansen, Technical Superintendent Fleet Management at Scandlines.