From Concept To Sea

23 June 2016

The Wärtsilä RT-flex50DF is designed for liquefied natural gas (LNG) carriers, Handysize tankers and bulk carriers, as well as feeder container vessel.
Click on the image for a 3D visualization of the Wärtsilä RT-flex50DF engine.

The first dual-fuel two-stroke engine employing the low-pressure X-DF gas admission technology developed by Winterthur Gas & Diesel (WinGD) has passed sea trials and is moving from concept to commercial operation as a marine main engine, the company said.

The five-cylinder, 500 mm bore, Wärtsilä RT-flex50DF engine employing X-DF technology is installed as the main engine driving a single propeller in the Ternsund, a low-emission 15 000 DWT chemical tanker. The ship underwent sea trials in May and is scheduled to be delivered by the end of June. The two-stroke dual fuel technology was developed to respond to the market requirements of providing a propulsion solution capable to run efficiently, effectively and safely on gas, on top of conventional heavy fuel oil or diesel oil, WinGD said.

During the trials, the Wärtsilä 5RT-flex50DF engine, rated 5850 kW at 102 rpm, was run continuously for several days in its gas mode and a series of automated fuel changeovers from diesel mode to gas mode and back were executed. In addition, as customary in sea trials, the engine was run at a range of load points in both gas and diesel mode, including a high load level set to fully exploit the sea margin of the Ternsund with its hull in new condition without fouling. All aspects of the trials have successfully passed, AVIC Dingheng Shipbuilding reports.

With an overall length of 147 m and a beam of 22 m, the 15 000 DWT Ternsund is a twin-hull chemical tanker designed to meet Ice Class 1A. It is the first of four vessels ordered by Terntank from AVIC Dingheng Shipbuilding. The Wärtsilä 5RT-flex50DF engine is matched to a design speed of 14.5 knots. It was delivered to the shipyard in October 2015 by WinGD’s engine manufacturer, Yuchai Marine Power Co., Ltd., based in Zhuhai, China. Destined to operate predominantly in northern European waters, the Ternsund will meet the strict limits on oxides of sulfur (SOx) in Sulfur Emission Control Areas (SECAs) because of the low sulfur content of natural gas. At the same time, the X-DF technology also enables compliance with IMO Tier III limits on oxides of nitrogen (NOx) in gas operation without additional exhaust gas after-treatment.

Ternsund was undertaken by AVIC International Ship Development Co., Ltd. (AVIC SHIP), Shanghai, China. It was completed by AVIC Dingheng Shipbuilding Co. Ltd., Jiangdu, China for Terntank Rederi A/S, which is based in Skagen, Denmark.

WinGD is joint venture between Wärtsilä and China State Shipbuilding Corp. (CSSC). The companies recently announced Wärtsilä would transfer its 30% of the company to CSSC, which controls 70% of the company. WinGD will continue to run as an independent company under the agreement.



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