Super Eco-ship A Human And Environmentally Friendly Ship

Super Eco-Ship – A Human and Environmental Friendly Ship by

M. Abdul Rahim * and Naoto Ikeda † Nippon Kaiji Kyokai

Abstract Super Eco-Ship has been developed as part of a Japanese national research project under the leader ship of the Ministry of Land, Transport and Infrastructure in cooperation with the industry with the aim of designing and constructing a next-generation coastal ship which is highly efficient and which has a reduced impact on the environment.

A number of innovative technologies have been

adopted in the design and construction of the Super Eco-Ship.

These include the use of an electric

propulsion system powered by a highly efficient super marine gas turbine (SMGT), contra-rotating pod propellers, and a new low resistance hull form. Various user-friendly support systems of automation have also been adopted in the Super Eco-Ship that enhances efficiency while streamlining shipboard operations thus resulting in reduced crew requirement. Presented in this paper is an outline of the Super Eco-Ship including the different systems used on the Super Eco-Ship.

Introduction Global warming is one of the important environmental issues, and as a means of addressing this problem, the Kyoto Protocol came into force on 16 February 2005. As one result of its adoption by Japan, efforts are being made to encourage a shift from land based rail and truck to seaborne modes of shipping and distributing goods in the transport sector in Japan as a measure for protecting the environment. Against this backdrop, a national research and development project aimed at designing and constructing a next-generation coastal ship for domestic service in Japan capable of highly efficient sea transport that also reduces loads on the environment has been initiated under the leadership of the Ministry of Land, Infrastructure and Transport (MLIT) of Japan in cooperation with industry and other stakeholders. Termed “Super Eco-Ship Project,” this project culminated in the *

Manager, London Office, Nippon Kaiji Kyokai

†

Manager, Machinery Department, Nippon Kaiji Kyokai

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demonstration trials on a test ship and the introduction into actual service of a Super Eco-Ship (SES). It is anticipated that the Project, and the human friendly and environmentally friendly ships that will result, will also help to facilitate the revitalization of coastal shipping in Japan. A number of innovative technologies are being adopted in the design and construction of the Super Eco-Ship. These include the use of an electric propulsion system powered by a highly efficient super marine gas turbine (SMGT), contra-rotating pod propellers, and a new low resistance hull form that takes advantage of the range of freedom offered in arranging the propulsion equipment, which is a notable benefit of pod propeller propulsion plants. Various user-friendly support systems of automation have also been adopted in the Super Eco-Ship that can be expected to enhance efficiency while streamlining shipboard operations. This includes systems that reduce the amount of work loads that needs to be done onboard ship, thereby making it possible to realize a reduction in the number of crew necessary onboard, while at the same time ensuring safe navigation and ship operation. For tankers, it also includes systems that reduce oil leakage and spillage that can occur as a result of human error during loading and unloading, which could contribute to marine pollution. This includes the use of improved centralized computer control and the use of electric rather than hydraulic powered systems. The construction of a 4,200 GT Super Eco-Ship, M.V. SHIGE MARU, was completed at the Niigata Shipyard of Niigata Shipbuilding & Repair, Inc. in 2007 (See Fig. 1). The ship, a coastal tanker, has been built to NK class and now experimented as a test ship incorporating the SES buttock hull design and electric propulsion using a CRP pod driven by a high-efficiency super marine gas turbine together with various support systems to reduce manpower onboard the ship.

Fig. 1

Super Eco-Ship M.V. SHIGE MARU

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Some of the systems employed in the Super Eco-Ship are as follows.

Super Marine Gas Turbine (SMGT) At present, most ships use diesel engines as their main propulsion system onboard. Even so, gas turbines offer many benefits over diesel engines. First, the amount of NOx emissions emitted from a gas-turbine is significantly less than that from a diesel engine, due to differences in the combustion characteristics of the two types of engines. Gas turbines are also smaller and lighter in weight, have lower noise levels and less vibration, and are easy to maintain. They are also very powerful for their compact size and are highly reliable. In spite of this, however, the use of such engines in marine applications has in fact been limited due to economic reasons such as higher fuel costs, higher component costs and other factors. Thus, a cleaner, greener, more highly efficient next generation SMGT engine that is designed to overcome these limitations is used in the demonstration ship of the Super Eco-Ship Project. This engine is one response to calls for improvements in the operating efficiency and onboard environment of coastal ships as well as for reductions in manpower onboard, and is also intended to encourage the expanded use of gas turbine engines onboard marine vessels (See Figs. 2 and 3). The SMGT engine developed as part of the Super Eco-Ship achieved a thermal efficiency of more than 38% during shop tests, which is significantly better than the performance of traditional industrial gas turbines. In addition, the SMGT engine has also been designed to be compatible with the use of type A heavy marine diesel oil, taking into consideration the types of fuels currently available for ship use.

Fig. 2 SMGT on board MV SHIGE MARU

Fig. 3 A cross Section of SMGT

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Major characteristics of the SMGT engine are as follows: 1) The combustor utilizes a dry, pre-vaporizing and pre-mixing lean combustion [dry low NOx: DLN] method in which neither water nor steam is injected into the combustor. Further, supplemental firing after the main combustion stage helps to reduce NOx levels by increasing combustion efficiency. 2) A regenerative cycle approach has been adopted using a compact highly efficient plate fin type regenerated heat exchanger (recuperator) to improve both thermal efficiency and fuel consumption. This system recovers heat from the exhaust which is then used to pre-heat the air delivered to the compressor prior to combustion. 3) The compressor consists of a four-stage axial flow compressor, adopted for the low pressure range, and a single stage centrifugal compressor, adopted for the high pressure range, for a total compression ratio of 8:1. 4) In order to enhance efficiency further, the design temperature at the turbine inlet is about 1,200ºC, which is 50 to 100ºC higher than that in comparable class gas turbines. As a result, it was also necessary to develop cooling blades with a very high cooling efficiency. 5) In order to better withstand the rigors of ship use, research has also been conducted into the development of measures to protect each part against corrosion, and into the development of structural bearings and seals capable of enduring the oscillations and movement of the hull, amongst other things.

Contra-rotating Pod Propellers Design plans call for electric motor driven contra-rotating pod propellers to be adopted in the propulsion system of the Super Eco-Ship. A full-scale model test of the contra-rotating pod propellers was carried out in July 2004 (See Figs. 4 and 5). Usually, the adoption of an electric propulsion system makes it possible to reduce the size of the machinery space thanks to the compact size of the engine system itself and the greater degree of freedom that becomes possible in laying out machinery and equipment. As a

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result, the amount of cargo space can be expanded. Further, the adoption of an electric propulsion system also makes it possible to reduce the amount of engine maintenance work that needs to be done, and low energy operation resulting from improved power management and lower vibration due to the constant speed operation of the electric generator motors becomes easy. In addition, the adoption of contra-rotating pod propellers makes it possible to achieve improvements in propulsion system efficiency due to the contra-rotating effect and thus obtain greater freedom in ship design. The adoption of a new “buttock flow” hull form that takes full advantage of these innovative characteristics in the Super Eco-Ship also makes it possible to realize substantial improvements in propulsive efficiency that can lead to fuel savings of as much as 10%.

Fig. 4 Schematic diagram

Fig. 5 Contra-rotating pod propellers fitted on SES

Human Friendly Support Systems A very high level of automation has been achieved in the Super Eco-Ship thereby reducing the onboard workload. The work environment has also been improved through low noise, low vibration and increased accommodation spaces. Some of the highly automated support systems are:

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• • • •

Navigation support system Berthing support system Cargo operation (loading and unloading) support system Mooring support system

The navigation support system includes a route planning and tracking system. The display unit employs an integrated indication system which displays the navigational information from the RADAR, ARPA and AIS together on the electronic chart display to make it easy to read on a single display. (See Fig. 6) The hovering and lateral movement of the ship towards the berth is finely controlled using the pod propeller and bow thruster thereby improving the maneuverability at berthing. The position and movement of the ship are constantly monitored and indicated on the display along with berthing speed and distance between the ship and berth both at bow and stern. (See Fig. 7)

Fig. 6 Navigation Support System

Fig. 7 Berthing Support System

The cargo operation is automatically carried out to preset cargo operation plan. The cargo pumps, ballast pumps, valves for cargo lines and ballast lines are operated by the system with necessary guidance being issued for confirmation by the operator at each stage. The conditions of cargo pumps, ballast pumps, valves, cargo and ballast tank level, etc are monitored and indicated on the display. (See Fig. 8) In the mooring support system, the tension and length of each mooring rope is monitored on the display with ship’s position using DGPS, and adjusted automatically and remotely to adjust external force. (See Fig. 9) 6

Fig. 8 Cargo Operation Support System

Fig. 9 Mooring Support System

These and other similar support systems are designed to help realize a safe reduction in the amount of manpower needed onboard while improving operational efficiency.

Environmental Impact The adoption of a SMGT in the Super Eco-Ship with the above features makes it possible to realize a 90% decrease in NOx emissions, a 60% decrease in SOx emissions and a 25% decrease in CO2 emissions, while at the same time eliminating the need for engine maintenance onboard the vessel. Moreover, use of such an engine also makes it possible to reduce the amount of fuel consumed by about 30% compared with conventional gas turbine engines. In addition, propulsive efficiency can be increased by as much as 10% with the adoption of contra-rotating pod propellers and the adoption of an optimal hull form. Safe and reliable operation is anticipated with the adoption of a LAN-based control and instrumentation system, as well as various other systems including the navigation support system, berthing support system, loading and unloading support system, and mooring support system, amongst others, that are designed to help realize a safe reduction in amount of manpower needed onboard while improving operational efficiency.

Conclusion ClassNK has actively contributed to the realization of this project at the request of the Ministry of Land, Infrastructure and Transport. Part of this work included assessing the safety and other aspects of the Super Eco-Ship from the design stage from the perspective 7

of ship classification. It also includes playing an important role in evaluating how effectively the various support systems with centralized computer system developed for enhancing shipboard control efficiency and operations noted above reduces the workload onboard ship. The test ship, a 4,200 GT SES design tanker, M.V. SHIGE MARU, incorporates the SES buttock hull design and electric propulsion using a CRP pod driven by a high-efficiency super marine gas turbine together with various support systems to reduce manpower onboard the ship. It is a notable example of an actual application of the results of the SES research and development being brought to fruition, thus bringing the next generation of ship design for a safer and cleaner marine environment yet another step closer to reality.

Acknowledgement The authors wish to thank all the parties associated with the development, construction, operation and testing of the Super Eco-Ship for their kind support and permission in presenting some of the results in this paper.

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