In English

Konsekvenser av varierande bunkerkvalitet för LNG-drivna fartyg

Consequences of varying bunker quality in LNG-powered ships

Axel Pedersen ; Carl Schenström
Göteborg : Chalmers tekniska högskola, 2016. 30 s.
[Examensarbete på grundnivå]

Because of stricter environmental regulations around the world concerning shipping and its emissions, ship owners and engine manufacturers are now forced to come up with solutions that match the new requirements. A road that some ship owners already have been chosen is to begin to run on LNG (liquefied natural gas), and several others are on the way. LNG has long been used ashore as fuel for power plants, and also for propulsion of LNG tankers that use their cargo as fuel. The vessels that are studied in this project are ships using LNG as fuel for propulsion of the ship when the cargo is anything other than LNG. Because of the lack of ships of this type, LNG powered ships that do not have LNG as cargo, there are very little information about what kinds of problems that may occur. Some problems with LNG can be due to varying bunker quality during operation. Quality changes during operation may occur because LNG constantly boils off to a certain extent, where certain substances in LNG (methane and nitrogen) boils off more than others. Should this continue for a long time, there will be a possibility for knocking and misfiring. These problems can also occur when bunkering LNG of different qualities. In this case rollover is also a possibility. The question that are desired to answer in this work is if the engine gets affected due to varying bunker quality during operation onboard ships and whether there will be any problems because of the different quality of LNG from the bunker suppliers. The method to accomplish this fell on surveys and interviews with experienced people. The result shows that there is no direct connection between a change in the bunker quality during operation and an effect on the engine. It however demonstrated that a problem because of varying quality from the suppliers are found, but without greater scope and impact. This may be because all the ships that were investigated receive bunker from the same supplier at all times and that they sail relatively short trips.

Nyckelord: LNG, Rollover, Knackning, Misfiring, Metantal, Avkokning, LNG-drift



Publikationen registrerades 2016-11-23. Den ändrades senast 2016-11-23

CPL ID: 245565

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