【作者】

Magnus Kronholm

【摘要】

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。ABSTRACT The arctic areas are environmentally very sensitive from both the airborne emission and fuel spill point of views. Operating in the arctic climate puts high demands on the equipment since the range of the ambient temperature is very wide. The new, stricter, Sulphur Emission Controlled Area limitation came into force for Baltic Sea area in the beginning of 2015 and the NOx Emission Controlled Area limitations are coming .The Finnish transport agency ordered the first LNG powered icebreaker to be delivered in 2016 that needs to fulfill these requirements. Ice-breaking vessels have traditionally been powered by diesel engines, but the advantages of the gas-powered reciprocating engines have made gas an alternative also for the high demands of this application. There are several solutions to meet this requirement, i.e. exhaust scrubbers, using low-sulphur diesel oil or LNG. Low-sulphur diesel oil is technically an easy choice, but the global consumption increase of distillate fuel can be a cost issue in the future. By using gas as the main fuel for propulsion of ships in the region, the airborne emissions are significantly reduced and the risk for oil spill is minimized. The use of LNG is technically more challenging but seems to be more stable in terms of fuel cost compared to other solutions to reach the same emission levels. The worldwide availability of natural gas is good, and the infrastructure for bunkering gas is continuously expanding. The development of the natural gas price has been stable, and operating on gas will be an economically viable solution for decades to come. New ship layout solutions are needed to adopt the LNG system. For example, making the LNG supply as compact as possible will reduce the length of double-wall piping. The fuelling infrastructure must be arranged in a way that the storage tanks for LNG can be kept within a rational size but still allowing reasonable endurance. Fuel storage on board is calculated for ten days. The previous requirement means that the network of LNG terminals for refueling must be comprehensive enough. There are also challenges in introducing gas as fuel as LNG and gas engine applications are new. New guidelines are developed to maintain safe and reliable operation. The main part of the development process will be handled by Hazard Identification Study and Hazard Operational Study processes, i.e. by Risk Based Design, because there is not enough experience to write exact rules. The operation modes of an icebreaker cover the whole range of its power resources, and the main engine solution must allow the use of maximum power regardless of the fuel the engines are using. The change of fuel type must also be done without any power cut. The Wärtsilä dual-fuel engines can provide operational flexibility and safety needed by this application. Furthermore, they comply with stringent loading demands without smoke emissions as well as the IMO Tier III emission standard. The sulphur and CO2 emissions are also significantly lower for a gas-powered engine compared to a diesel engine of similar output. The Finnish icebreaker is using Wärtsilä 34DF engines as the main machinery and a Wärtsilä 20DF engine as the auxiliary engine because the solution was considered to meet the prime requirements for the icebreaker in all operational conditions. This Finnish icebreaker will be a very important future reference, e.g. for the arctic offshore supply vessels, when the emission requirements will become more stringent and, in general, the number of sulphur emission control areas will increase in the coming years.

【会议名称】

第28届CIMAC会议

【会议地点】

芬兰 赫尔辛基

【下载次数】

5

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