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Tanker Shipping & Trade

Green Tanker Tech

Wed 11 Jul 2018 by Craig Jallal, tankers and markets editor

Green Tanker Tech
Elena H with ballast tanks filled with IMO-specified invasive animal-free water

 

Tanker newbuilding undergoes maiden voyage with shore-side ballast water

A tanker built in the Netherlands has had ballast tanks filled with IMO-specified invasive animal-free water via the Damen InvaSave system. 

The 5,000-dwt newbuild product tanker has been loaded with clean ballast water from a Damen InvaSave containerised treatment system for its delivery voyage from the Netherlands to Argentina. It will be operated by Navios Logistics, a subsidiary of Navios Maritime.

Inland coastal tanker Elena H will make its maiden voyage from the Netherlands to Argentina on its own keel but, once in service, will remain permanently in local waters, where it will not need to treat its ballast water.

In a statement, Damen Green Solutions explained that instead of installing a ballast water management system (BWMS) for this single international trip, its InvaSave system supplied clean ballast water that met IMO’s D-2 standard.

The statement did not say when the voyage is due to take place, but vessel-tracking site Vesselfinder.com shows the ship was still berthed in the Netherlands on 2 July.

Damen Green Solutions sales manager Philip Rabe said in the company’s statement that InvaSave has proved itself to be “a versatile tool to treat ballast water of vessels without the need to install a BWMS.” He said the company’s goal “is to build up a reliable worldwide ballast water service network” and that it is in talks with several yards and harbour service providers around the world.

Scrubbers are not fit-and-forget items

The running costs of scrubbers, and possible vessel downtime, need to be factored into the choice of equipment. 

French flue gas treatment and desulphurisation manufacturer, LAB SA, has suggested that tanker companies should consider lifecycle costs, including the cost of repairs, maintenance, and shipyard time, as part of the analysis when selecting exhaust gas cleaning, or scrubber, technology.

While the majority of scrubbers in use today are constructed from high-end alloys, there have been reports in the market of corrosion on some marine scrubber units. LAB has developed a composite scrubber - available in open, closed or hybrid format - as an alternative to its range of alloy units, providing customers with more choice and removing the risk of corrosion.

LAB’s composite units have undertaken thousands of hours of operational service onboard Brittany Ferries Mont Saint-Michel over the last three years. There has been no unscheduled repair and downtime, or associated yard costs or lost commercial opportunities while the vessel was out of service.

Neil Anderson (LAB SA): Consider running costs when choosing scrubbers

LAB SA director of marine technologies Neil Anderson said: “With the prime focus understandably on the economics, and the potential financial advantage to be gained from continuing to burn less expensive heavy fuel oil instead of the costlier, low sulphur fuel, discussion around the practicalities of design and installation has been muted. However, for those considering scrubbers, it is important to understand the available options in terms of design and materials.”

LAB SA’s DeepBlueLAB SOx corrosion-free composite units can be located on deck or around the funnel area, making them easier to install and maintain. Moreover, all engines and the vessel’s boiler can be linked to one scrubber unit, meaning there is less complex piping for installation. The composite material is 20-30% lighter than a similar version made from high-end alloys, reducing load at sea and reducing fuel consumption, while also allowing for a more cost-effective and environmentally friendly recycling processes.

Mr Anderson continued: “While scrubbers do not represent a single solution for the whole of the merchant fleet, for many ship owners, operators and cargo owners it is a viable and commercially compelling option. While there is a tendency to look at scrubber technology as a one-off capital expenditure, it is essential that the whole lifecycle costs are properly considered.”

The corrosion-resistant properties of the composite material makes it a robust and durable long-term solution, while its location can allow for increased accessibility and improved maintenance.

The DeepBlueLAB SOx scrubber is the only system on the market that can be manufactured in either composite or high-end alloys and available as an inline, offline or multi-streaming solution. Although inline systems can only be fitted to one engine, offline multi-streaming solutions offer greater flexibility, as they ensure that the scrubber can treat multiple engines, including auxiliary engines and boilers.

Low sulphur fuels require a new approach to cylinder lubrication

Maersk Fluid Technology's (MFT) SEA-Mate Blending-on-Board lubrication system is said to reduce fuel consumption by 1.5% at slow steaming and reduces lube oil consumption by up to 40%.

System oil is used as hydraulic oil for operating and controlling engine components and systems, fuel injection equipment, exhaust valves and turbochargers. Under normal circumstances, the system oil degrades between system oil changes, becoming thicker, losing its detergent characteristics and becoming contaminated by wear particles and possibly by leakage from the upper cylinder through the piston stuffing box.

When blending-on-board (BOB) is employed to produce cylinder-lubricating oil from the in-use system oil and an appropriate high base number oil product, the engine’s system oil is constantly replenished with fresh clean oil and therefore the protection and efficient operating of the engine is continually maintained.

BOB was developed in-house by the AP Møller subsidiary Maersk Fluid Technology (FLT) as a means of producing cylinder lubricant suited to different fuel types and engine operation modes for crosshead two-stroke engines. According to FLT, BOB significantly improves the system oil, making the engine more efficient and reducing fuel consumption. The consequent reduction in exhaust emissions is also beneficial to the environment.

Jens Byrgesen (MFT): BOB was developed for the Maersk fleet, and is available for all vessels

“Users of BOB have been impressed with the improved engine performance and maintenance that have resulted from the cleaner system oil and have welcomed the cost savings the improvements bring,” said MFT managing director Jens Byrgesen.

The BOB system was developed over more than a million hours of on-board testing in vessels in Maersk's worldwide fleet, and the system has recently been independently verified through tests at a stationary power plant in Barbados.

Selective catalytic reduction technology replaces urea with diesel

In order to meet the emissions limits set by IMO Tier III (see table), marine diesel engines typically use a system of selective catalytic reduction (SCR) in the exhaust flue. SCR technology uses a simple chemical reaction to neutralise the NOx in the exhaust. The catalyst promotes the reaction between NOx and a reducing agent such as ammonia at the relatively low temperatures of an exhaust stream.

This process produces harmless nitrogen and water. A high efficiency SCR is capable of removing up to 99% of the NOx. The technology has found widespread application in reducing NOx from power plants and in diesel cars, where it is often termed blue technology, Blutec or similar names.

On ships, the reductant needed is usually ammonia in the form of an aqueous urea solution, gaseous or aqueous ammonia. In diesel cars, the reductant is known as Adblu or similar, which is liquid urea recovered from farm animals.

Although there is no shortage of farm animal-derived urea, it does have its drawbacks in the shipping industry. Urea requires separate tanks and thus takes up cargo carrying capacity and space. It also needs to be sourced and it is an extra cost.

ADNOX A/S, a Danish research and development company, has released details of its Advanced Diesel NOx reduction method, “ADNOX”. The ADNOX System is an SCR system using diesel oil as the reductant (instead of urea) offering more than 80% NOx reductions. The injected diesel is cracked and converted to heat, leaving 50% more heat for recovery.

This means that no extra storage tanks are required, and no crystallisation of the reductant is experienced. Further to this, diesel oil is non-corrosive, and the evaporation and mixing of the diesel oil with the exhaust only needs a short pipe length, upstream the ADNOX reactor.

ADNOX A/S was founded in 2012 with the purpose of improving SCR technology. Founder and chief executive Ole Fanøe wanted to revolutionise the SCR NOx reduction system using only diesel oil as reductant.

The oil injected is converted to heat, that can be recovered and used for production of steam and electricity. The cost of oil corresponds to the cost of urea, for a urea-based SCR system. The ADNOX SCR system can be used on all diesel engines, from two-stroke to four-stroke and marine to power plant applications.

The ADNOX SCR system uses approximately 7% of the total oil consumption, an amount equivalent to 14 L/MWh. The oil injected is cracked on the multi-functioning catalyst and takes part in the NOx reduction (NOx -> N2 and H2O) which produces heat, increasing the exhaust temperature at the ADNOX reactor outlet.

The increased exhaust temperature means an exhaust-boiler can be installed after the ADNOX reactor and high-quality steam can be produced and used for production of water or electricity. In the case of an exhaust-boiler, an electricity amount in kW corresponding to 7% of the shaft power output can be produced, i.e. more than 80 % NOx reduction can be achieved at no extra overall cost of reductant. Furthermore, the ADNOX SCR system weighs approximately 40% less than a standard SCR system.

On four-stroke diesel engines, the ADNOX reactor is installed after the turbocharger turbine. On two-stroke diesel engines, the ADNOX reactor is installed between exhaust receiver and turbocharger turbine inlet.

The ADNOX SCR system is patented and has achieved an “Approval in Principle” by DNV-GL, confirming no risk of explosion. The ADNOX SCR system is fit for both retrofit and newbuilding application. In early 2018, a majority stake of the company was acquired by Hans Jensen Lubricators A/S, also of Denmark.

IMO code controlling NOx emissions

The IMO code on the control of diesel engine NOx emissions is listed in the mandatory regulations 13.8 and 5.3.2 respectively, NOx Technical Code 2008 (resolution MEPC.177(58) as amended by resolution MEPC.251.(66)).

The NOx control requirements of Annex VI apply to marine diesel engines of over 130 kW output power. Different levels (Tiers) of control apply based on the ship construction date, a term defined in regulations 2.19 and hence 2.2, and within any particular Tier the actual limit value is determined from the engine’s rated speed:

Tier

Ship construction date on or after

Total weighted cycle emission limit (g/kWh)

n = engine’s rated speed (rpm)

n < 130

n = 130 - 1999

n ≥ 2000

I

1 January 2000

17.0

45·n(-0.2)

e.g., 720 rpm – 12.1

9.8

II

1 January 2011

14.4

44·n(-0.23)

e.g., 720 rpm – 9.7

7.7

III

1 January 2016

3.4

9·n(-0.2)

e.g., 720 rpm – 2.4

2.0

The Tier III controls apply only to specified ships while operating in Emission Control Areas (ECA) established to limit NOx emissions; outside such areas the Tier II controls apply. A marine diesel engine that is installed on a ship constructed on or after 1 January 2016 and operating in the North American ECA and the United States Caribbean Sea ECA must comply with the Tier III NOx standards.

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