Mitsubishi Heavy Industries said it has received an order from Hitachi Zosen Corporation for a high-pressure gas supply system enabling use of natural gas as fuel in marine engines.
In lieu of conventional heavy oil, the system supplies liquefied natural gas, injected under high pressure, to the engine. This configuration curbs emissions of sulfur oxides (SOx), nitrogen oxides (NOx) and carbon dioxide (CO2), thus contributing to reduction of environmental loads, the company informed in a statement.
Delivery of the system is scheduled for the second half of 2016, for installation at Hitachi Zosen’s Ariake Works in Nagasu-machi, Kumamoto prefecture. After use in gas-fuelled demonstration testing of a marine diesel test engine, Hitachi Zosen will use the system to provide gas fuel for the marine diesel engines that the company manufactures.
The order is the second for this system received by MHI, as well as the first system delivered to Mitsui Engineering & Shipbuilding. The latest system enables higher gas pressure supply to the engines for enhancement of gas-fuelled performance.
With the new system, LNG is pressurized and delivered by a liquid pump. The system features a compact configuration and low power consumption. The adoption of a hydraulic driven pump system eliminates the need for a speed reduction mechanism, facilitates variable speed adjustment, and also enables installation in ships where space is limited.
The gas supply system consists primarily of four units: a unit that produces compressed natural gas (CNG) by raising the LNG’s pressure and then heating the gas to normal temperature according to engine load fluctuations; a hydraulic unit that serves as the power source; a CNG bottle unit to buffer fluctuations in CNG pressure; and a gas combustion unit that safely disposes of low-pressure off-gas and uses the waste heat as a heat source.
Image: MHI