LNG carrier to have Wärtsilä dual fuel two stroke engine

Wärtsilä RT-flex50DF

MARCH 25, 2014 — A 14,000 cu.m LNG tanker being built to operate along the Chinese coastline is to have a five-cylinder Wärtsilä RT-flex50DF low-pressure, two-stroke, dual-fuel engine.

The engine, together with the gas valve unit and other relevant equipment, will be supplied to shipbuilder Qidong Fengshun Ship Heavy Industry Co., Ltd, which is building the new vessel according to Chinese Class Society (CCS) standards for Zhejiang Huaxiang Shipping Co.Ltd.  

When delivered in August 2015, the vessel will operate along the Chinese coastline to meet domestic LNG transportation requirements.

Wärtsilä unveiled its low-pressure, dual-fuel technology for two-stroke engines in November of last year. In gas mode, the engines are compliant with the IMO Tier III emission regulations without need of any exhaust gas cleaning systems. Compared to other technologies, says Wärtsilä, studies show that the Wärtsilä low pressure DF engines offer capital expenditure reductions of 15-20 per cent, while on the operating expenditure side, the ability of low pressure DF engines to operate on gas at all loads, including idling and maneuvering, substantially reduces costs.

“We feel that the Wärtsilä dual-fuel engine is excellent, especially the low pressure two-stroke DF version, which we see as being an innovation that meets the demand of the market,” says Mr Cai Dejiang, General Manager of Zhejiang Huaxiang. “As owners, we are very satisfied with this engine technology and believe that it will capture a large share of the market. We look forward to seeing this technology extended to cover other cylinder bores.”

“This second contract for the Wärtsilä low-speed dual-fuel engines in a few months demonstrates the fast market acceptance of this ‘game-changer’ technology,” says Mr. Martin Wernli, Vice President two-stroke, Wärtsilä Ship Power. “This is the first time that Wärtsilä low-speed DF engine will power an LNG carrier. It represents a very feasible solution for this vessel class. The extension of Wärtsilä low-speed DF engine portfolio to bigger bore sizes such as the Wärtsilä X62DF and Wärtsilä X72DF engines will further expand the range of applications for the low-speed DF engine family to larger container vessels, tankers, LNG carriers and bulk carriers.”

Wärtsilä’s low pressure LNG concept is a lean burning Otto-cycle gas engine that has additional liquid fuel back-up capability.

Wärtsilä low pressure DF technology allows stable operation on gas across the entire load range. This means that at low loads (below 15 per cent), there is no need to switch to diesel fuel.

The engine uses a low pressure gas handling system with a maximum 16 bar pressure. LNG and air are mixed in the cylinder prior to compression and, therefore, no additional external engine compressors are needed and additional parasitic load is avoided. Consumption of pilot fuel is approximately just one per cent of the total energy at full load.