The world’s first ME-GIE ethane-combusting two-stroke engine has been delivered from MAN Diesel & Turbo licensee Mitsui Engineering & Shipbuilding Co., Ltd. (MES) in Japan. The Mitsui-MAN B&W 7G50ME-C9.5-GIE is the first engine in a series of three.
Further research has led to new possibilities for this engine leading to new prospects for multi-fuel combustion including the combustion of waste gas. The benefits of the diesel-type combustion are now fully exploited in the ability of the two-stroke engine to run on almost any gas quality without efficiency reductions, and in the complete combustion maintained by a relatively high gas injection pressure.
|The engine top section of a 6-cylinder ME-GIE engine. Click to enlarge.|
The engine will be able to run on a mixture of LPG, among which are included VOCs, and methane or ethane with unchanged gas mode efficiency. The mixture may contain as much as 50% LPG and the findings so far indicate that even larger amounts of LPG may be added to the gas.
The ME-GI engine represents the culmination of many years’ work and gives shipowners and operators the option of utilizing fuel or gas depending on relative price and availability, as well as environmental considerations. The ME-GI uses high-pressure gas injection that allows it to maintain the numerous positive attributes of MAN B&W low-speed engines.
Research indicates that the ME-GI engine delivers significant reductions in CO2, NOx and SOx emissions. Furthermore, the ME-GI engine’s negligible fuel slip makes it the most environmentally friendly technology available. As such, the ME-GI engine represents a highly efficient, flexible, propulsion-plant solution. An ME-LGI counterpart that uses LPG, methanol and other liquid gases is also available, and has already entered service operating on methane.After methane, ethane is the second-largest component of natural gas with a content that varies from < 1% to > 6% by volume. However, before natural gas can be used as a commercial fuel, it must be processed to remove impurities, including ethane. Like many hydrocarbons, ethane is isolated on an industrial scale from natural gas, usually by liquefaction at cryogenic temperatures. Its chief use is within ethylene production. In 2016, Mitsui Engineering & Shipbuilding completed the first ME-GIE ethane-operated two-stroke diesel engine. The engines will be for propulsion of three ethylene carriers, which primarily will carry liquid ethane as cargo.
The ME-GIE engine was originally designed for the combustion of ethane gas, however, research has revealed that it is possible to operate the engine on volatile organic compounds as well. Accordingly, it is also a potential solution for the propulsion of shuttle tankers and VLCCs.—René Sejer Laursen, Sales & Promotion Manager at MAN Diesel & Turbo
MAN Diesel & Turbo sees significant opportunities in the development of this engine since the engine may also run on almost any form of waste gas. The waste gas could be the light hydrocarbons or volatile organic compounds (VOCs) emitted from crude oil during storage and when loading/unloading of crude oil.
This opens for new applications of the engine in for example shuttle tankers, for power generation in remote power plants or in off-shore applications, such as floating production storage and offloading vessels (FPSOs), where waste gas is abundant and poses a potential environmental hazard.
Tier III operation can also be met in combination with selective catalytic reduction (SCR) systems, either low- or high-pressure SCR.
The engine can be delivered in the power range 5-90 MW.