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Mitsubishi Heavy Industries, Ltd. (MHI) says it has developed Japan's first system for supplying high pressure gas that will enable the use of natural gas as fuel for marine engines.

The company has an agreement in place with Mitsui Engineering & Shipbuilding Co., Ltd. (MES) for delivery of the first unit. The use of liquefied natural gas (LNG) as fuel with the new system will also lead to a reduction of carbon dioxide (CO2) emissions compared with heavy fuel oil.

MHI's new high pressure gas supply system delivers LNG at 30 megapascals (MPa) gas by liquid pumping, which is characterized by its compact configuration and lower power consumption. The hydraulic driver is adopted for the liquid pump without a speed reduction mechanism, which is said to facilitate variable speed adjustment and high layout flexibility.

The company commercialized the system leveraging its broad technological expertise and R&D achievements not only in cryogenics and the construction of LNG carriers, but also in the field of marine engines, general machinery and sealing.

The system consists mainly of a unit to transfer LNG at high pressure according to fluctuations in the demand of the engine, a hydraulic unit as power source, a unit to produce a compressed natural gas (CNG) by heating LNG to normal temperature, a CNG bottle unit to buffer the CNG pressure variation and a gas combustion unit to safely dispose low pressure off-gas and to use its exhaust heat as a heat source.

MHI says that by combining the system with 2-stroke, low-speed marine diesel engines, the engine will be a high efficiency propulsion system. By using LNG as its fuel, an engine integrated with the new system also realizes reductions in emissions of sulfur oxides (SOx) and nitrogen oxides (NOx).

Delivery of the first unit to MES is slated to take place in early 2013. After installation at MES's Tamano Works in Okayama Prefecture, the system will undergo demonstration tests using marine diesels manufactured by MES.

The Japanese shipbuilding industry has been highly active in the development of so called 'eco-ships' in recent years. MHI says it views eco-ships as one of the key areas its Shipbuilding & Ocean Development division is focusing on with the aim of expanding its product line.

At the same time, the company has also been strengthening its engineering business in a quest to provide environment-related technologies to entities both in Japan and abroad.

MHI says it plans to aggressively promote the new high-pressure gas supply system by promoting it as an environment-related technology and as a means of differentiating its business from its competitors.