189 Ship 5 case is unknown due to the undefined FSC value. The X value in the combustion equation, 
190 which is the excess air ratio used, is assumed to be 2 in all cases (Ntziachristos et al., 2016). 
191 
Table 2: Fuel characteristics of ships — Estimated FSC, SO» and CO, concentration of the exhaust gas at the exit of the funnel 
Ship Number 
FSC(% S m/m) 
Funnel exit SO, 
Concentration 
(ppm) 
Funnel exit CO, 
Concentration 
(ppm) 
Ship 1 0.26 
Ship 2 ] 0.11 
Ship 3 ) 321 
78 
“oz 
6? 
300; 
Ship 4 
7.1 
Ship 5 
Emm m — pm 
192 *Undefined value — SO, was measured below the detection limit of the monitoring station. 
193 2.2 Modelling Setup 
194 The production of CO2and SO results to estimate the FSC from ongoing vessels conducted 
195 through the use of simulations. For the present work, steady-state CFD modelling is used to 
196 simulate plume dispersion. In Figure 2a, the top view of the actual geometry is schematically 
197 illustrated. The ship is moving along the dashed line while the MS location is fixed. The wind 
198 blows and disperses the plume (greyscale-coloured puffs) that originates from the ship’s stack, in 
199 this example, towards the MS location. 
200 The transition from the real geometry to the modelling setup geometry takes place. The 
201 simulation design is illustrated in Figure 2b, where the Virtual Monitoring Station (VMS) is a point 
202 in space that corresponds to the sampling location of the actual MS, relative to the vessel and its 
203 path line is parallel to the ship’s track. This is assumed to move at the same relative velocity as the 
204 ship does, while the ship location is considered fixed. The virtual motion of the MS while crossing 
205 the plume helps to produce a signal that is equivalent to the plume signal of the moving vessel. 
206 received by the actual measurement instruments, but by solving this problem under a steady state. 
207 In other words, the time domain is converted into a space domain. 
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