Resumen de Metodología para el cálculo de emisiones de NOx en buques portacontenedores: aplicación en puerto modelo y al cálculo de emisiones ponderadas
The objectives of this thesis are the layout of a model for the calculation of the NOx emissions from the ships during the port operations, the development of a tool to carry out the mentioned calculation, the validation of the method applied and also the validation of the software designed jointly by the General Directorate of the Merchant Marine (this researcher has represented this organization) and the University of Vigo. So, bearing in mind the above paragraph, it is firstly applied an analytic method to calculate the NOx from the marine diesel engines. This methodology is applied to the calculation of the emissions generated in a model port by a specific type of ship. In this stage all the containerships that called at Barcelona in 2009 have been selected. The methodology distinguishes and analyses in depth the different operative stages that take place during the port period and it has initially been completely developed in two containerships with the aim of enlightening the method, afterwards the calculation has been extended to the rest of the ships indicated in the above paragraph by means of a worksheet that incorporates all the details applied in the two model ships. Later on a calculation as weighted emissions is carried out in the same model ships above indicated according with the test cycles defined in the NOx Technical Code. This stage of the thesis can be justified due to the fact that for validating the analytic method used in the paper, it is necessary a normalized base to compare the results, so the results obtained as total weighted emissions by using the test cycles of the mentioned regulation have been required and used. This calculation is firstly developed by the method defined in the thesis and secondly by means of the simulation software indicated in the first paragraph. After getting the weighted emissions results, queries and searches have taken place to obtain the values declared by the engines makers of the model ships. These values are included in the thesis body and a comparative analysis of the different results is made in the conclusions section. The analytic method referred to at the beginning of this summary is supported by the use of different variables. Firstly the called emission factors (EF) have to be fixed. They are defined for the different types of engines and for each pollutant. The EF¿s mainly depend on different parameters that are detailed in the thesis. The acquisition of the EF¿s is done empirically, mainly by the engines makers and the Recognized Organizations responsible for the pre-certification survey. In this case, reference values for different engines classified by type and nominal speed were obtained through the professor James J. Corbett from the University of Delaware. In the thesis, they have been extrapolated and approximated to polynomial functions to cover the engine working range required in this paper. Later on, bearing in mind the typology of propulsion and generating plants of the ships studied, these plants have been classified in the different curves previously designed to get the most accurate results. The specific fuel oil consumption (SFOC) is other main variable of the method developed in the thesis. To estimate the SFOC¿s of the ships engines, a division based in reference engines has been carried out and after that the ships engines have been classified in its corresponding division. The reference engines SFOC¿s have been supplied by the manufacturers themselves, which only provide the values corresponding to the common working loads. Afterwards, they have been extrapolated and approximated to polynomial functions for the complete range required by the operative conditions at port. Once the emission factors and the specific fuel oil consumptions are known and after estimating the load ranges of the main and generating plants and the timing taken by each operative phase, the NOx emissions for all the containerships of the thesis are obtained.
