In response to the IMO 2020 regulations that came into effect on 1st January 2020 under the MARPOL Annex VI Regulation, Scrubbers or Exhaust Gas Cleaning Systems (EGCS) have become a preferred option for ship owners as vessels with scrubber installations are allowed to run on HFSO under the new regulations.
These scrubbers are used to remove particulate matter and harmful components, such as sulphur oxides (SOx) and nitrogen oxides (NOx) from the exhaust gases generated as a result of combustion processes in marine diesel engines. The scrubbing process of filtering out toxic chemicals enables better pollution control, ensuring that no damage is done to human life or the environment.
However, these hazardous pollutants, extracted during the scrubbing process, can heavily corrode the pipes of the scrubber. The wash water from scrubbers is highly acidic, hence, the corrosion of scrubber pipes. The deterioration is further aggravated by high temperatures of exhaust gases. Therefore, the scrubber and associated pipework should be regularly checked for any signs of leakage or corrosion.
Since the beginning of this year we have witnessed an increase in these corroded scrubber pipes and the demand for repair. We have successfully completed several scrubber overboard pipe renewals in the past 6 months in a timely and efficient manner, allowing vessels to stay on their tight sailing schedule.
Preliminary visual inspection
Recently, we have completed a scrubber pipe renewal on a 87,000dwt bulk carrier here in Singapore. The following illustrates how we, Dive Marine Services, approach and carry out such high precision, underwater repair jobs.
The vessel was anchored in Singapore and experienced water ingress as a result of a corroded scrubber outlet pipe. Hence, our experienced dive team was mobilised to the vessel’s anchorage location and conducted a preliminary inspection of the affected scrubber outlet pipe.
Removal of the existing pipe
A customised cofferdam was then installed over the pipe outlet, temporary sealing off the space beneath the water surface that allows the repair works to be carried out internally in a dry environment.
Due to the limited space, the disassembly of the existing, corroded pipe and valve are done step-by-step, following a systematic and pre-planned methodology.
With the offsite pre-fabricated section of the pipe, the spool piece was properly aligned and welded onto the outlet using the full penetration welding technique. Once the NDT measurements have been taken from the welding, the mechanical and chemical cleaning was carried out before applying two protective layers of coating inside the pipes for corrosion protection.
Installation of the new pipe/section
The coatings are highly chemical resistant providing a long-lasting protection of the scrubber overboard pipe.
After the pipe had undergone successful Non-destructive Testing (NDT), the cofferdam was removed and our divers completed the grinding of the pipe’s external parts and applied the epoxy before carrying out a final visual inspection.
If you are experiencing any issue with your scrubbers, contact us for more information on scrubber pipe replacements or a bespoke quotation. Dive Marine Services also offers a wide range of other specialist underwater repair and maintenance services for your assets in Singapore, Gibraltar, Panamas, Scandinavia and the Baltic States.
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Eugene’s responsibilities include business development and performance of the company’s business. He has spear headed the diversification of businesses and developed the various subsidiaries within the Group.
