Technical and economic assessment of LNG use on cruise ships

摘要

Cruise ships spent most of their time into areas where international emissions restrictions apply and moored into ports where there are strict regionalational limits for sulphur and nitrogen oxides emissions.For this reason,in order to comply with current and future International Maritime Organization(IMO)rules,new emission reduction technologies should be implemented.In this work,the use of natural gas for ship propulsion has been analysed and applied on a specific cruise ship: a comparison with today in-use technologies has been carried out.In particular,the use of natural gas fuelled combustion engines has been considered in order to quantify the possible environmental benefit for a typical one week Mediterranean Sea cruise.A process simulation model of a Liquefied Natural Gas(LNG)propulsion plant,which includes a cryogenic storage tank,has been developed.The model allows calculating gas composition variations that can influence fuel methane number.Results show that a strong reduction of greenhouse gases and operating costs is possible,but plant investment costs are higher.The return on the investment can be shortened when considering the introduction of a carbon tax.