Page 42: of Maritime Reporter Magazine (May 2021)

TECH FEATURE SCRUBBERS

The Scrubber Uptake:

Economics & Technologies

Expectations are high that exhaust gas scrubber technology demand will soon be resurge. But what lessons have been learned from installations and which type will dominate?

nstalling scrubber systems on ships structural changes and reinforcements process can take some time. On a cruise that were never envisaged to have that may be needed, said Olli Somerkal- ship, there is also guest disturbance to them on board has brought well doc- lio, COO, Foreship. As well as extra think about: the noise; the smells; and

Iumented challenges for older ton- tankage and other heavy components, the closure of some public spaces. Some nage, with accurate drawings and docu- he said, retro? tting a scrubber can in- cruise lines also indicate that an addi- ments sometimes hard to source. Where volve re-building parts of a vessel’s tional crew member is required to take class documentation is concerned, structure can be complex. “The required care of complex hybrid plant. meanwhile, different societies can have modi? cations can affect damage stabil- subtly different requirements and inter- ity; if tanks are added asymmetrically Operating lessons pretations vary by individual surveyor. for example. Passenger ships present With the number of scrubbers in op-

At a time when the owners backing particular challenges, where adding a eration rising, lessons have been ac- scrubbers over low sulfur content fuels scrubber system can bring the need for cumulating for cargo ship owners too. to meet IMO 2020 emissions require- a complex recalculation of the vessel “DNV has offered its thoughts on corro- ments report faster than expected re- stability. If the effect of the installation sion problems in scrubbing water in the turns on investment, any lessons learned on the vessel’s stability is not carefully discharge piping passing through hull merit review. Any future oil price re- considered, it can cause stability chal- penetrations,” said Somerkallio. covery will likely rein? ate the favorable lenges for the rest of the ship’s service The reference is to a well-documented differential high sulfur content fuels en- life, especially on cruise ships. Scrub- incident where corrosion in SOx scrub- joy over their low content counterparts. bers also use plenty of power, especially ber piping between the overboard valve

Having secured around 60 exhaust gas as a proportion of what is available on- and a ship’s hull led to a large quan- scrubber references, naval architecture board cargo ships, while closed loop tity of seawater entering a ship engine and marine engineering ? rm Foreship or hybrid systems create tank capacity room. During the damage survey, the suggests that future projects offers a issues that are sometimes passed over.” spool piece and the diffusor diluting the bountiful packet “lessons learned”, from In addition to ? nding the space on acidic wash water out? ow were found detail design to installation. Its scrubber an existing ship to install a scrubber to be heavily corroded, with the most selection recommendations are fully in- system, one of the main challenges for likely cause a ? aw in the application of dependent and based on cost, complex- cruise ship retro? ts has been owners de- the protective epoxy coating. DNV GL ity and the ship’s operating pro? le, and siring to avoid the ‘off-hire cost’ of tak- now requires an annual inspection of the its experience base includes open loop, ing working ships out of service. spool piece, either by Ultrasonic Thick- closed loop and hybrid systems, a vari- Therefore, many cruise owners have ness Measurements or by a diver.

ety of class rules and yard installations decided to do most of the work while the Cumulatively, installations have also in Europe, North America and Asia. vessel is operating. “Changes on the ves- ? agged up the heat loads generated by sel’s watertight integrity, like tank modi- scrubber systems as a problem for ma-

Melding Economics & Tech ? cations and bulkhead penetrations, can- chinery spaces. “Fire safety risks also

Should the economics driving scrub- not be done when the ship is at sea,” said have to be attended to, where scrub- ber uptake appear compelling for an in- Somerkallio. “This means that such in- ber system piping manufactured from dividual owner, they must ? rst consider, stallations must take place in short bursts combustible materials. In cases where for instance, space availability and any when the ship is in port, so that the entire ? res have occurred during the installa- 42 Maritime Reporter & Engineering News • May 2021

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