Last month our diver/technicians carried out several scrubber overboard pipe repairs in Rotterdam. On both a 140-meter roro vessel and a 200-meter container ship the corroded areas of the scrubber pipes were grinded out and rewelded. In both cases the pipes were protected with Ecospeed, a chemically resistant coating produced by Subsea Industries. The same protection was given to the three new pipes that were installed on a 400-meter container ship.

Exhaust scrubbers are systems that filter out all harmful toxins from exhaust gases of marine diesel engines. These can severely corrode the pipes of the scrubber which can result in water ingress if not handled quickly enough.

Scrubber pipe replacement

This was the case for one of the three overboard pipes of the 400-meter container ship. The owner asked us to replace the leaking pipe and to perform an inspection of the other two pipes. This revealed that they were also heavily corroded.

In communication with the owner it was decided to replace these scrubber pipes during the same operation to prevent new leaks in the near future.

Three cofferdams were constructed at our workshop based on the drawings sent by the customer. The team installed these over the outlets of the pipes. This allowed them to perform work inside the engine room without water ingress.

Next the team cut away the old pipes. The shell plating was then prepared for the installation of the replacement part. New pipes had also been constructed at our warehouse in Antwerp with a diffuser and flange already in place. The pipes were then positioned and secured with a full penetration weld. Next an independent inspector carried out NDT testing of the welding work.

To prevent the new pipe from corroding, the inside was coated with Ecospeed. This product is produced by Hydrex sister company Subsea Industries.  Ecospeed is highly chemically resistant. Taking into account the nature of the process taking place inside a scrubber, this is essential for a lasting protection of the pipe. Ecospeed can also be used to protect a newly installed scrubber system from day one.

Lasting corrosion protection

The corrosion on the scrubber overboard pipes of the other two ships was less severe. It was situated on the flange weld seams. A full replacement of the pipes was not needed.

In both cases our diver/welders grinded away the affected area before rebuilding it back to its original thickness with clad welding.

When the welding was complete the surface was polished and a MPI was carried out by an independent inspector.

The inside of the pipes was then coated with Ecospeed to keep them safe from further corrosion.

Conclusion

We offer a full package to owners that are experiencing similar damage. We replace the corroded exhaust pipe while your vessel stays on schedule and we make sure that you will not have to call us again in a few months’ time for the same problem.

Most ships sail on a tight schedule. We know how important it is to prevent any loss of time. Our technical department has many years of experience in drawing up a repair plan that fits in perfectly with a vessel’s schedule. Working in shifts or splitting up an operation in stages are just a few of the many ways we can make sure that the impact of the repair is limited to the absolute minimum.

Contact us to find out how we can assist you. We are available 24/7.

+32 3 213 53 00
hydrex@hydrex.be