Slow Speed Steaming

[The Dieselduck]

Slow progress Wärtsilä fits upgrade kit
Jamie Dale, 4 December 2008 Lloyds List

FINNISH engine manufacturer Wärtsilä has started to retrofit its new Slow Steaming Upgrade Kit to the German-owned containership Aglaia, which will help reduce fuel costs and engine wear, writes Jamie Dale.

Shipowners have turned to slow steaming this year, firstly to offset higher bunker costs and then to deal with a tonnage oversupply.

“Every charterer is asking for it,” said a London broker yesterday.

But without modification to vessels’ engines, there was increased risk of engine fouling and excessive component temperatures when operating continuously below 50% engine load, Wärtsilä said.

The upgrade kit is designed to improve the fuel consumption for low-speed engines and allows vessels to operate at any power in the range of 20%-100%.

“This means that ships can sail continuously at sea speeds down to some 60% full speed,” Wärtsilä said.

German owner Koepping Shipping made the first orders last November for two containerships, each with a Wärtsilä low-speed engine. The two ships, Aglaia, pictured, and Lantau Arrow, are fast feeder containerships.

A source told Lloyd’s List that the units were expected to take around two and a half months to fit, with work on the first vessel expected to be completed in February 2009.

Koepping Shipping managing director Joerg Koepping said: “The kits will give these ships considerable flexibility to adapt to difficult market conditions, allowing great cost savings while slow steaming, but retaining the capability for full speed whenever necessary.”

Wärtsilä said that installation and commissioning of the upgrade kits could be completed during normal commercial operation and during normal port calls.

[conrod]

I can help but think this is all alittle bit of ..........whats that word, deja vu..........as a 3/E on a box boat, powered by a Sulzer 6 RND 76, I beleive, we used to change injectors regularly depending on what the charter required. Each set had different nozzles........slow speed, and .........yes..........high speed. Fancy that.........Oh and by the way, this was back in 1986

[Madzng]

I know that my company are looking at implimenting this system, but last time I spoke with Wartsila it was still being finalised. I guess they think they have got it right......

Below info and more available from the Wartsila Website.

The Upgrade Kit is available for all RTA and RT-flex engines with multiple turbochargers. For ships that must comply with the IMO NOX emissions regulations, the restrictions imposed by the emissions limits will be evaluated in each case and a customized turn-key package may be offered.

The concept of the Upgrade Kit is to cut out a turbocharger when the engine is to be operated at low load. This increases the scavenge air delivery at low load for better combustion and more optimum temperatures of engine components. The cut-out point depends upon the engine configuration.

The Upgrade Kit involves fitting shut-off valves in the exhaust duct before the turbocharger turbine and in the scavenge air duct after the compressor, together with a bypass line to keep the turbocharger rotor spinning at a preset constant speed. The valves are remotely operated and the Kit includes fitting a control system to operate the valves.

Low-speed two-stroke crosshead diesel engines are normally operated in a load range above 60 % CMCR.

Slow speeds result in a continuous engine operation between 20 % and 40 % engine load. The Slow Steaming Upgrade Kit allows continuous operation between 20 % and 100 % CMCR without additional operational restrictions, assuring reduced fuel consumption.

Main principles

Engine operation in the load range between 20 % and 100 % CMCR without any additional restrictions
Can be fitted during commercial operation
Selective turbocharger shut-off (accordingly, the upgrade kit is yet available only for multi-turbocharger engines)
Electronically-controlled turbocharger cut-off without compromising engine reliability
Retrofit Pulse Lubricating System for proper low-load cylinder lubrication assurance required
Package content

Turbocharger shut-off valves installation including operating control system
Engine performance analyses, eventually required overhaul and parts optional
New engine tuning standard (optional supply)
Cabling and installation
Material, man-power and transportation (FAS vessel)
Complete upgrade kit installation and commissioning
Emission measurement & certification
Retrofit Pulse Lubricating System

A typical brake specific fuel consumption (BSFC) curve for RTA and RT-flex engines, as standard and with the Upgrade Kit for Slow-Steaming. Note that it is not desirable to operate engines continuously at less than 50% load without modification.

Wartsila.jpg (16.59 KiB) Viewed 3968 times

ESTIMATED FUEL COST SAVINGS
• Engine type 12RTA96C
• CMCR 68640 kW @ 102 rpm
• Load 45% of CMCR
• Annual running hours 7000
• HFO price US$ 650.00 / ton

Slow steaming scenario at 45 % engine load
• Saving in SFOC 8.8 g/kWh
• Total annual savings 1’236’756 US$

Slow steaming scenario at 45 % engine load compared to 75 % original engine load
• Saving in SFOC 3.5 g/kWh
• Total annual savings 15’970’074 US$