Dr Raphael Zaccone (Università di Genova, DITEN)
In recent years the International Maritime Organization (IMO) has introduced increasingly stringent regulations regarding sulphur oxides (SOx) and nitrogen oxides (NOx) emissions from the marine engines. Also the theme of reducing carbon dioxide (CO2) marine emissions is considered with increasing attention. A reduction of the above emissions, as known, could be achieved by adopting more efficient ship systems and using fuels with low carbon content, for instance natural gas (NG). This paper presents the application to dual-fuel marine engines of an original Variable Layout Waste Heat Recovery (WHR-VL) steam plant, designed considering the different exhaust gas stack temperature limits depending on the used fuel type: generally no less than 160 °C for diesel fuels, without limits in case of natural gas fuel. When using diesel fuels, a single pressure, superheated steam plant scheme is adopted, while a dual pressure one is used for engine fuelled with NG. In both configurations the produced steam is sent mainly to a steam turbine (for electric energy production), while a part is used to meet the on-board uses, as required by the type of vessel. A quantitative evaluation of the proposed installation is presented.
Prof. Ugo Campora (Università di Genova, DIME)