Pertaining to the sensitive topic of the Scrubber discharge line overboard pipe, we have been dealing with an ever increasing number of reported leaks in this distance piece of the EGCS discharge line.
Just only 3 months in operation a number of vessels are reporting water ingress to the Engine Room and have to box cement the OB or urgently resort to expensive underwater repairs to continue the EGCS operation. This is mainly due to the wrong design choice or the poor application during installation. In such cases where docking is not a possibility we perform remote underwater replacement of the overboard distance pieces/diffusors via our Principals HYDREX globally and the renewed pipe is coated with ECOSPEED* coating, or proactively we may only coat the pipe without replacement if unnecessary. There exist a number of “special” coatings in the market (glassflake, ceramic, PE, etc.), none however will warrant 10 years for this application. In practice, ECOSPEED will last the vessel lifetime with proper application.
*ECOSPEED is the main product line of Subsea Industries NV, a Hydrex company
The various available Overboard distance piece designs, including sleeves or direct welding of high alloy corrosion resistant metals, each come with its disadvantages (stagnant water, gasket leaks, galvanization corrosion, welding imperfections). From our experience with this issue arising from the aggressive low pH scrubber effluent, we have identified the method with ECOSPEED applied on mild steel and directly welded on to the hull to be the safest and probably amongst the most economical solutions there is available and will last for the expected lifetime of the Scrubber operation. Ecospeed demonstrates unparalleled resiliency against the low pH effluent, which can also be seen at the attached photo report and Scrubber applications. Applications include inside Scrubber towers, all closed loop EGCS effluent piping, holding tanks etc..