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This paper proposes an active-control concept that mitigates the liquid sloshing in a topside vessel by reducing the excitation source, thus extending the scope of sloshing mitigation. To verify the concept proposed, sloshing response in partially liquid-filled topside vessels was numerically investigated under various wave and vessel conditions.This study confirmed that vessel location on the top deck exhibits a weak correlation with the sloshing response. Although liquid sloshing is not very sensitive to the vessel location, it is beneficial to place the topside processing vessels as close as possible to gravity center of the floating production facilities (FPS/FPSO). It is evident that liquid sloshing in a topside vessel is closely related to the incident direction of the wave. The perpendicular incidence results in the minimum sloshing response; the parallel incidence leads to the maximum sloshing response. It is, therefore, essential to properly orient the vessel to establish perpendicular or close-toperpendicular incidence status. It is also verified that liquid sloshing is significantly increased with length-to-diameter (L/D) ratio of a vessel. The horizontal vessels with larger L/D suffer from severe liquid sloshing. Because vertical vessels have a minimum L/D = 1.0, they always exhibit better antisloshing performance than the horizontal vessels. In addition, it is advisable to prevent a vessel from operating near the resonance-wave condition.Although the active control concept shows attractive advantages over the conventional approach, it is more feasible for layout of topside vessels on a newly built FPS/FPSO. Because most of the floating-production systems are not built from scratch such that the topside processing vessels can be placed in the optimal position and orientation but are retrofitted for a topside vessel to fit onto a limited deck space, the passive-control approach may be more applicable. Generally, a combination of the active and passive approaches should be considered to minimize liquid sloshing in a topside process vessel.

Floating Production Systems (FPS) and Floating Production Storage and Offloading (FPSO) units are normally subjected to complex wave and current under varying sea conditions. As a consequence, performance of the topside oil & gas processing train is adversely affected by liquid sloshing as a result of the wave, especially for parcially liquid filled vessels based on gravity separation. In order to achieve the intended operating performance, it is essential to effectively control or mitigate the sloshing response in each process vessel. The current works on liquid sloshing in a moving vessel are mainly focused on suppressing the sloshing behavior using various perforated baffles, which is actually a passive control approach based on viscous damping. This paper, however, extends the scope of liquid sloshing and proposes an active control option, which mitigates the sloshing response by reducing the excitation source. To verify the active control concept, liquid sloshing in partially liquid filled vessels were numerically investigated under various wave and vessel conditions.The CFD study has confirmed that vessel location on the top deck shows a weak correlation with the sloshing response under the roll and pitch excitations. Although the sloshing response is not very sensitive to the vessel location, it is beneficialable to locate the separation module or critical oil/gas process vessels as close as possible to the gravity center of the FPS/FPSO; it is evident that liquid sloshing in a topside vessel is closely related to the incident direction of the wave. The perpendicular incidence creates a minimum sloshing response; the parallel incidence generates a maximum response; while the angle incidence results in a sloshing response somewhere between the perpendicular and parallel incidences. Considering that the angle incidence is the most frequently encountered case in practical operation, it is essential to orientate the vessel to establish a perpendicular incidence according to the wave encountered. It is also verified that sloshing response is significantly increased with a vessel length-to-diameter ratio (L/D). The longer horizontal vessels experience more liquid sloshing related problems. Since vertical vessels can be considered as vessels with minimum L/D=1.0, they always exhibit better anti-sloshing behavior than the horizontal vessels. It is also important to prevent a vessel from operating near the resonance wave condition.Although the active sloshing control approach shows attractive advantages over the convential approach, it is more applicable for layout design of the newly built topside processing vessels. Considering that most of the floating production systems are not built from scratch where the topside processing equipment can be placed in the optimal position and orientation but are rather retrofitted for the new equipment to fit onto an already limited deck space, the passive sloshing control approach may be more feasible in this application. Generally, a combination of the active and passive appr...

The objective of this study is to develop a shipping emission inventory model incorporating Machine Learning (ML) tools to estimate gaseous emissions. The tools enhance the emission inventories which currently rely on emission factors. The current inventories apply varied methodologies to estimate emissions with mixed accuracy. Comprehensive Bottom-up approach have the potential to provide very accurate results but require quality input. ML models have proven to be an accurate method of predicting responses for a set of data, with emission inventories an area unexplored with ML algorithms. Five ML models were applied to the emission data with the best-fit model judged based on comparing the real mean square errors and the R-values of each model. The primary gases studied are from a vessel measurement campaign in three modes of operation; berthing, manoeuvring, and cruising. The manoeuvring phase was identified as key for model selection for which two models performed best.