A Quantum Leap In Shipping :Hull design and engine technology combine for more efficiency, fewer emissions in shipping vessel
by bo svensson
There is an increasing interest in improving seaborne transportation and lessening its impact on the environment. It is driven by factors such as increasing fuel prices, stricter emissions regulations and a public concern and awareness for the environment in general. As a consequence, the industry involved is concentrating research and development in finding ways to reduce the cost of shipping and reduce the negative environmental impact of seaborne transports.
There are different routes to achieving the goal of reducing the environmental impact of shipping. One way is to improve the hull of the vessels and to reduce speed. Another solution would be to select a less polluting fuel, such as liquefied natural gas (LNG). The industry is investigating alternative fuels for shipping, and LNG is expected to become an attractive option. LNG reduces emissions and is expected to cost less than fuel oil in the future because of large world reserves of natural gas.
DNV is introducing its new Quantum 9000, which has been designed to be more efficient and environmentally friendly than existing ships without introducing major complications when the ship is to be built or operated. By introducing a new system for LNGfueled ships, DNV and MAN Diesel & Turbo are taking the Quantum concept ship one stroke further. Both the hull design and the machinery and arrangements have been redesigned.
“When we introduced this concept a year ago, we called it a concept ship. And it still is, but by improving the machinery as well as the hull design and arrangement, we have moved it one step closer to becoming a real ship,” said Eirik Byklum, DNV’s project manager, who introduced the first version of the Quantum concept vessel a year ago and has also been in charge of its second phase. The hull of the Quantum 9000 has been given an increased beam for stability and a minimum ballast water requirement. A wide deck provides for an increased deck-load capacity. An optimization of the hull form, and a bulb design with a low block coefficient was designed to provide low resistance over a wide speed range, draught and trim. Another important detail for performance is the use of lightweight material, which results in lower fuel consumption.
A number of other improvements, such as increased cargo capacity and reduced need for ballast water, have been made possible by adopting a “twin island” arrangement. By moving the navigation bridge and accommodation five bays forward and the engine room and chimney six bays back, additional container space has been created in the vessel. With the more forward navigation bridge, containers can be stacked higher in front of the bridge (approximately 250 more) without losing visibility. And approximately 750 more containers fill the space behind the bridge above deck and below deck using the space created by the engine room’s position further to the back of the vessel.
Other major design factors are related to the engine. MAN Diesel & Turbo has developed a gas-fueled two-stroke ME-GI engine — 9S80ME-C9.2-GI. In addition to having a dual-fuel engine, Quantum 9000 achieves full fuel flexibility and at the same time meets the upcoming Emission Control Area (ECA) requirements. The 9S80ME-C9.2-GI engine provides power of 40 590 kW at a speed of 78 r/min. The bore of the engine is 800 mm and the stroke is 3450 mm. The length of the engine is 14.1 m and the height is 13.5 m.
The ship’s energy efficiency also meets IMO’s Energy Efficiency Design Index (EEDI) to a higher degree. The ME-GI engine will fulfill IMO Tier 3 NOx levels when utilizing the exhaust gas recirculation (EGR) technology. This technology is developed by MAN Diesel & Turbo for its complete lowspeed B&W engine program. “We are proud of the result. By mak-ing simple modifications, we have achieved high fuel efficiency, high fuel flexibility and high reliability,” said Lars Ryberg Juliussen, senior manager, MAN Diesel & Turbo. “The Quantum 9000 introduces LNG to the preferred containership propulsion system and thus makes LNG more available to containership owners.”
The ME-GI engine offers flexibility in selecting the best fuel. The vessel’s LNG tank capacity is 6500 m3 and the HFO tank capacity is 4000 tons. The pilot oil can be low sulfur marine gas oil for ignition and backup fuel, which is particularly useful when sailing in ECAs. The ship’s LNG fuel capacity will be similar to that needed to sail from East Asia to the East Coast of the United States — without any loss of cargo space. In addition to the use of gas fuel, the machinery includes waste heat recovery to improve the energy efficiency and exhaust gas circulation to reduce the emissions. Up to 30% reduced CO2 emissions is credited to the waste heat recovery system, actually a combinedcycle concept, under which the steam turbine generator produces electricity to the ship’s grid system.
“The size and cost of the waste heat recovery system is considerable and the installation is complicated, but it is well compensated by an energy saving of 9 to 12% of the main engine SMCR power,” said Ryberg Juliussen. MAN Diesel & Turbo has developed designed and manufactured its first exhaust gas recirculation (EGR) system for a two-stroke marine diesel engine aimed for operation on a container vessel in service. In partnership with A.P. Moller-Maersk, the EGR prototype system has been installed and commissioned on the vessel Alexander Maersk. Its main engine is a Hitachi B&W 7S50MC Mk 6, with a specified maximum continuous rating of 10 126 kW at 127 r/min. The Alexander Maersk has been en route from Europe to Northern Africa.
“Thirty to forty percent of the exhaust gas can be recirculated, and the EGR system has demonstrated an 80% reduced NOx emissions. And the gas fuel system provides for 95% reduced SOx emissions without methane slip, a problem commonly associated with dual-fuel engines,” said Ryberg Juliussen. “This is not an issue with the MEGI engine due to operation according to the diesel cycle principle.”