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SMM Gives Scrubbers a Chance to Shine


When it comes to the cost of the shipping industry meeting environmental regulations, the next expensive outlay on most owners’ shopping lists will be the purchase of a ballast water treatment system. That will need to happen within the next five or six years, but very shortly after that, owners will have another expense to consider – that of meeting the final MARPOL Annex VI sulphur in fuel limit.

At MEPC 70 in October this year, the IMO is scheduled to deliver its verdict on the availability of fuel oil needed for meeting the reduction in sulphur from the current 3.5% to 0.5% outside of ECAs that will be required under Annex VI in either 2020 or 2025. Such a significant reduction is only comparable to one in January 2015, when the sulphur limit in ECAs was reduced from 1.0% to 0.1%. Since January 1, 2010, there has been a 0.1% maximum sulphur requirement for fuels used by ships at berth in EU ports.

Fuel Premium

Compared with the 0.1% on sulphur in ECAs, the 0.5% global cap seems quite benign; but the cost implications are the main concern of hard-pressed operators. The premium on 1.0% low-sulphur fuels over standard 3.5% fuels has varied over time between 50% and more than 100%. Even with today’s low bunker prices, doubling the fuel cost of operations is something that no owner can be relishing.

Meeting ECA limits has been achieved in many ways; using distillates, blending fuels and with emission abatement technology or scrubbers. Ships that burn LNG or other alternate fuels are not affected because such fuels rarely contain sulphur.

Because LNG has not taken off as quickly as expected, and because converting diesel engines to run on LNG is an extremely expensive option, scrubbers are emerging as the likely favored option for most ship operators whenever the 0.5% becomes effective. With a potential market of around 60,000 vessels, the opportunities for system makers are extensive.

Reducing the Risk

Ships that currently must switch fuels to satisfy the rules have to manage the process carefully because despite some automatic switching equipment being available, it is fraught with danger and several incidents of fire and power loss have been recorded. Adding a scrubber would reduce the risk and reduce the cost of fuel used into the bargain.

Courtesy of P&O

Courtesy of P&O

When Annex VI was first adopted, the use of abatement technology was not envisaged but was later included. Many believe that its use will be essential if shipping is to remain economically viable although the changing bunker price obviously affects the payback period which was once down to as low as a few years.

Scrubbers have improved considerably since the first was installed in 2006 on the P&O ferry Pride of Kent and have now become mainstream proving extremely popular on cruise ships and ferries as well as cargo vessels of varying types.

A Growing Industry

From the initial two or three scrubber makers, the number has gradually expanded and is accelerating. Keeping up with numbers is not easy, as some of the newcomers are not well known names in the marine industry and seem to appear suddenly and without much fanfare. Most have a background in treating exhaust gas streams from shore-based industries.

More importantly, the systems they are producing are shrinking in size and weight compared to first-generation products, making them more attractive to operators of smaller and mid-size vessels. Fuji Electric claims to produce the smallest, with its Cyclone technology allowing a system just 7m tall and 2m in diameter for a 10MW engine but that claim is likely to be contested by several other system makers.

Membrane Scrubbing


Courtesy of Triton

As the name suggests, scrubbers wash the sulphur compounds out of the exhaust stream using water in a wet system or some reactant in a dry system. A third type of technology – membrane scrubbing – is a relative newcomer that employs a combination of the two. One scrubber maker, Triton, has also developed a device called DSOX-20, which removes some of the sulphur from the fuel before ignition rather than from the exhaust as is the conventional way.

For the sulphur oxides in the exhaust to react with the scrubbing water in a wet system the water needs to be alkaline. That means most seawater is usable, but fresh or brackish water needs added chemicals, usually sodium hydroxide (NaOH), but the Yara (formerly Green Tech Marine) system uses cheaper magnesium oxide, as do some others.

Wet systems come in three types; open loop, closed loop or a version that can operate in either mode. Open loop types use seawater whereas the closed loop types use chemically dosed process water.

In Force at SMM

At SMM this September, scrubber makers are expected to be out in force, with at least 13 names confirmed as of mid-June, and more could be present either as unknown newcomers or represented by agents. Other system makers known to be active in the field are not included in the directory of exhibitors on the SMM website. Our listing:

  • AEC Maritime (B7-448)
  • Alfa Laval (A1-226)
  • Andritz (A5-609)
  • Clean Marine (B7-132)
  • CR Ocean Engineering (B7-312.5)
  • DuPont Belco (B7-312.10
  • Ecospray (B3UF-140)
  • Envairtec (A4-219)
  • Fuji Electric (B2UF-101.1)
  • LAB (A1-109)
  • Saacke (A3-314)
  • Wartsila (B6-312)
  • Yara (A1-305)


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