Winterthur Gas & Diesel Ltd. (WinGD), developer of two-stroke low-speed gas and diesel engines used for propulsion power in merchant shipping, has had its first dual-fuel two-stroke engine equipped with a low-pressure gas admission system successfully complete its Type Approval Test (TAT). The TAT took place at the works of WinGD’s Chinese licensee Yuchai Marine Power Co., Ltd. (YCMP), based in Zhuhai, China in early December 2015.
The TAT, on a 5 cylinder, 500 mm bore Wärtsilä brand RT-flex50DF engine employing WinGD’s dual-fuel (X-DF) technology, was witnessed by representatives from major Classification Societies ABS, BV, CCS, DNV-GL, KR, LR, NK and RINA. The dual-fuel engine is available in 5-cylinder up to 8-cylinder configuration, covering a power range from 4,775 to 11,520 kW at 99 to 124 rpm and allows merchant vessels to safely and reliably run on Liquefied Natural Gas (LNG).
With the TAT successfully completed, WinGD’s X-DF technology is now fully ready for commercial use in marine propulsion applications. Accordingly, this particular YCMP-built 5RT-flex50DF engine will be delivered in January 2016 to the shipyard building four 15,000 DWT tankers ordered by Terntank Rederi A/S, based in Skagen, Denmark as propulsion power. The tankers will operate mostly in northern European waters designated as Sulphur Emission Control Areas (SECAs).
The YCMP-built 5RT-flex50DF will enjoy two further distinctions. As well as being the first engine with WinGD’s two-stroke low-pressure dual-fuel X-DF technology for a commercial application, it represents a central element in the implementation of an EU-supported Joint Industry Project (JIP) aiming at greatly improving the environmental compatibility of energy transportation in the Baltic sea.
Under the title “Into The Future – Baltic SO2lution”, the project centres on cooperation between shipowner Terntank, marine solutions provider Wärtsilä, engine designer Winterthur Gas & Diesel, fuel and bio-products supplier North European Oil Trade (NEOT) and energy and environmental consultant Wega Enviro. It promotes the development of more environmentally sustainable and energy-efficient shipping in the Baltic Sea, and aims to validate dual-fuel propulsion concepts at sea, based on the high efficiency and intrinsically low emissions of SOx, NOx and particulates of engines burning LNG.
Accordingly, the RT-flex50DF engines with X-DF technology were chosen for the Terntank tankers due to their ability to achieve emissions of SOx and particulate matter at very low levels, NOx emissions are far below the levels demanded by IMO Tier III in ECAs. CO2 emissions are reduced by some 25 percent compared to conventional diesel engine operated on low sulphur diesel fuel.
In addition to the Terntank application of WinGD X-DF technology, the EU funded project also plans to promote retrofits of this more environmentally-friendly propulsion technology to achieve emissions reductions from existing vessels and, in parallel, the building of the prerequisite LNG infrastructure in the Baltic region.
“The successful TAT is proof that WinGD low-pressure X-DF Technology is not only commercially competitive, but also fulfils all the safety standards required”, notes Mr. Marcel Ott, General Manager Dual-fuel Technology at WinGD’s headquarters in Winterthur, Switzerland. “And, at the same time, the adoption of the RT-flex50DF engine for the Baltic SO2lution shows that the technology is already acknowledged as a very environmentally-friendly propulsion option”.
WinGD low-pressure DF technology
The low-pressure gas admission system designed and developed by WinGD for its X-DF engine series draws on Wärtsilä’s long experience with what has become a well-proven industry standard technology on medium-speed dual-fuel engines. In contrast to high-pressure gas injection engines, which operate on the Diesel cycle, WinGD’s low-pressure X-DF engines works on the lean burn Otto cycle when operated in gas mode – i.e. ignition of a compressed lean air-gas mixture by injection of a very small amount of liquid pilot fuel.
As demonstrated during the Type Approval Test, WinGD X-DF engines are characterised by stable combustion inherently low NOx emissions and high overall system efficiencies as well as safe gas operation. In terms of NOx, WinGD X-DF engines undercut IMO Tier III limits for Emission Control Areas (ECAs) by considerable margins without any additional measures, such as EGR or SCR while running on gas.
Moreover, with the low-pressure gas admission the gas fuelling system on the X-DF engine series does not require any high-pressure electrically-driven compressors, considerably reducing equipment costs, on-board energy consumption and maintenance during operation.
(Source: Winterthur Gas & Diesel Ltd)