New Ethane Carriers Use Cargo, Fuel MAN ME-GI Engines
MAN Diesel & Turbo say that Ocean Yield ASA, the Oslo-based shipowner, has placed orders for three LEGCs (Liquefied Ethylene Gas Carriers) of 36,000 cbm capacity, to be built at Sinopacific Offshore & Engineering, China. Each will be powered by a single MAN B&W ME-GI low-speed, dual-fuel engine. The engines will run on the ethane cargo, and this will be the first time, according to MAN, it has been used as fuel to propel an oceangoing vessel.
Hartmann Schiffahrt, part of Hartmann AG, the German ship-owning and management group, has acted as technical leader on the LEGC project, while Gaschem Service, another Hartmann division, is commercially responsible for the employment of the vessel. The vessels are scheduled for delivery in August, October and December 2016 respectively.
MAN Diesel & Turbo reports that ethane was chosen as fuel, in preference to HFO, due to its more competitive pricing as well as the significantly shorter bunkering time it entails. As a fuel, its emissions profile is also superior to HFO – in which respect it is similar to methane – and compared to HFO contains negligible sulphur, 15-20% lower CO2 and emits significantly fewer particles under combustion. MAN Diesel & Turbo also states that the ME-GI engines will be set up such that they can easily be converted to run on methane as an alternative, as per the owner’s wish.
Ethylene carriers are generally considered the most sophisticated of all gas tankers and are capable of carrying most liquefied gas cargoes, but also ethylene at its atmospheric boiling point of −104 °C. These vessels have insulated, 5% nickel-steel cargo tanks and can accommodate most liquefied gas cargoes up to a maximum specific gravity of 1.8 at temperatures ranging from −104°C to +80 °C at a maximum tank pressure of 4 bar.
While ME-GI engines have been designed for use by several, different fuel types to date, ethane is a new departure. Ethane is one of the natural-gas liquids (NGLs) that are naturally occurring elements found in natural gas (and frequently separated removed and sold as a separate product), and include propane and butane, among others.
The ME-GI engine
MAN explains that this engine represents the culmination of many years’ work and gives shipowners and operators the option of utilising 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 that have made them the default choice of the maritime community.
An ME-LGI counterpart that uses LPG, methanol and other liquid gasses is also available, and has already been ordered.