The path to a zero sulphur emission marine industry is well-set. It started in January 2015 targeting to a global cap of 0.5% within 2025, with intermediate but challenging steps for the whole marine industry.

There are several compliance options:

The usage of distillate fuels and the Branded ECA  marine fuel. There are some common advantages as the simplified fuel and waste stream operations in which you don’t need to treat any water, you have a limited CAPEX to retrofit, a dedicated MGO/MDO circuit and very importantly there is no cargo space loss. There are also big challenges like the high fuel oil cost, differential higher than 150$ ton, the lower lubricity compared to the high-sulphur fuel and the Wax formation.

The liquefied natural gas which has great advantages because it is likely to maintain long-term fuel price advantage, also a clean burning addressing the NOx and SOx regulations at the same time. Its supply chain is not well developed but it will be at 100% in 10/15 year time. The conversion option is not so attractive because it’s three times more expensive than a scrubber system retrofit and the ships have to accommodate 7 times the cubic footprint for gas tanks.

With an exhaust gas cleaning system, operators can always burn the low-cost fuel, greatly available and far more affordable compare to distillates. As for the challenges, we have the initial capital investment, the waste water management and the slight increase in operations complexity.

In the end what counts most is the operators’ point of view that was captured from the Lloyd’s Register latest sulphur survey. Taking a look to the strategies that operators think are more viable for the future after 2020, the LNG and exhausted cleaning systems options are the most popular. While since 2015, the usage of distillate fuels have been more popular among the marine industry.

Scrubbers are an effective and IMO approved SOx abatement devices using alkaline water, such as seawater, to convert harmful SO2 into harmless aqueous SO4. There are added benefits by using scrubbers like global acid rains prevention, the particulate removal and the noise attenuation.

The map below shows our experience of executed projects in land-based and application of marine scrubber system. We have great experience in America as well as in Far-East and Europe.

Dierico 1

There are five well-known essential components of a scrubbing system.

  1. A source of water (seawater, fresh water +reagent)
  2. Centrifugal pump(s)
  3. Scrubbing tower
  4. Treatment plant for the wash water
  5. Monitoring system (air and water continuous monitoring)

There are three typical operating modes. The easiest is the open loop where sea water and its alkalinity are used to control pH, no chemicals are used in the system. The closed loop operational mode uses fresh water and base reagent to control pH instead. The system is not subject to alkalinity/water temperature variation and the system has the highest efficiency. Capital expenses are also lower because you don’t need special alloys to sustain the chlorine content of the sea water. The most flexible solution is the hybrid mode where you can use a combination of both the operating modes where the closed is preferable during port operations (no water discharge) while the open loop during sailing at full power (no usage of chemicals and water discharge to sea).

About design configurations, the single-stream, is the preferred solution for cruises and the ferries where you can have multiple and narrow funnels surrounded by ship’s superstructures. Shipyards can easily fit the towers for each exhaust gas source to reduce the amount of the installation costs (steel modifications).

About the cargo market, the multi-stream approach is the preferred one because shipyards have to insert the scrubbing tower from the top of the funnel with limited or absent steel modifications. In fact using this configuration operators can treat multiple exhaust sources with a single tower: auxiliary engines, main engines and boilers.

Above text is an edited article of Marco Dierico’s presentation during 2016 GREEN4SEA Conference & Awards

You may view his video presentation by clicking here


Click here to view all the presentations of 2016 GREEN4SEA Conference & Awards

The views presented hereabove are only those of the author and not necessarily those of  GREEN4SEA and are for information sharing and discussion  purposes only.


DiericoMarco is the business development manager Europe for DuPont Marine business, mainly involved in promoting the exhaust gas cleaning systems business. He joined DuPont in 2014 after a seven year experience in the most relevant Italian shipbuilding group: Fincantieri S.p.a. He spent 6 years in the basic design department for cruise and ferries taking care of several aspects of a ship design, from stability calculation, weight evaluation to the technical specifications. Most recently he spent a year in the engineering department for the machinery systems and he was in charge of a project for the integration of the B.A.T for DeSox and DeNox on board of cruise ships. He serves customers around Europe (with a special focus on Greek and Italian territory) and offers his experience to prepare tailored technical proposals for the passengers and cargo market (dry & wet), newbuildings and retrofits applications. He holds a marine engineering degree from the University of Trieste and a maritime science diploma. Passionate about new technologies applied to the marine industry.