Sloshing Damage Estimation for Liquid Transfer Between Floating Structures
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Solution Overview
Problem
Existing liquid cargo transfer operations between floating structures, such as LNG carriers and FSRUs, are prone to sloshing-induced tank damage due to wave agitation, which can compromise the integrity of tanks containing flammable or explosive liquids like LNG, especially during prolonged operations.
Innovation Solution
A method and device that utilize meteorological and oceanographic forecasts to estimate the probability of sloshing damage by determining wave incidence angles, significant wave heights, and filling levels, providing users with indications to adjust the common heading or transfer parameters to minimize risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid cargo transfer operations are carried out between floating structures, then the liquid cargo can be transferred from one structure to another, but the tanks are subject to sloshing caused by wave agitation which can compromise tank integrity
Solution Approach 1:
The system performs preliminary assessment of sloshing risk by obtaining meteorological and oceanographic forecasts, calculating wave parameters, and determining a sloshing risk indicator before the transfer operation begins. This allows operators to take preventive measures or adjust operations before dangerous sloshing conditions occur, thereby protecting tank integrity while enabling cargo transfer when safe.
Solution Approach 2:
The system continuously monitors wave conditions, tank filling levels, and calculated sloshing risk indicators during the transfer operation. Based on this feedback, the system can alert operators to adjust the transfer rate, reposition floating structures, or pause operations when sloshing risk exceeds thresholds, thereby maintaining tank integrity throughout the cargo transfer process.
2Quantity of substance
If the transfer operation takes a significant amount of time, then large-capacity FSRU or FLNG production units can be served, but the likelihood of climatic conditions causing sloshing increases
Solution Approach 1:
The system obtains meteorological and oceanographic forecasts covering the entire expected duration of the transfer operation before it begins. This preliminary assessment allows operators to evaluate the cumulative sloshing risk over the full transfer period and adjust the transfer rate or schedule accordingly, enabling safe transfer of large cargo quantities even during prolonged operations.
Solution Approach 2:
The system dynamically adjusts the sloshing risk assessment based on real-time wave conditions, wave period, and tank filling level throughout the transfer operation. This dynamic evaluation allows the transfer rate to be optimized - increasing it when conditions are favorable and decreasing or pausing it when sloshing risk increases - thereby enabling large cargo transfers while adapting to changing environmental conditions.
3Productivity
If the tank filling level is increased to improve transfer efficiency, then the transfer operation is completed faster, but the sloshing-induced stresses on tank walls increase
Solution Approach 1:
The system continuously monitors tank filling level and calculates its effect on sloshing characteristics. Based on this feedback, the system provides recommendations to adjust the transfer rate - slowing down the fill rate when the tank is partially full (when sloshing is most dangerous) and allowing faster filling when the tank is either nearly empty or nearly full (when sloshing is reduced). This enables efficient transfer while controlling sloshing-induced stresses.
Solution Approach 2:
The system changes the operational parameter of transfer rate based on the current tank filling level. By dynamically adjusting the transfer rate according to filling level, the system optimizes the balance between transfer efficiency and sloshing mitigation - using faster transfer when safe and slower transfer when sloshing risk is high, thereby reducing sloshing-induced stresses while maintaining productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables effective risk management by allowing users to modify operations to reduce the likelihood of tank damage from sloshing, maintaining the integrity of floating structure tanks.
Implementation Method 1
the LNG contained in the tanks is agitated by the effect of waves. The agitation of the liquid, generally referred to as 'sloshing'
Data Source
Figure 1~2
Figure 3A
Figure 3B~4
AI summary
The invention relates to a method (300) for estimating the probability of damage caused by the sloshing of a liquid load during an operation of transferring said liquid load from a first floating structure (1) to a second floating structure (40), the first floating structure (1) and the second floating structure (40) being connected with one another during the transfer operation so that the first floating structure (1) and the second floating structure (40) are oriented with a shared heading (99). The method comprises the steps of estimating (307) the probability of damage of at least one tank of at least one of the first and second floating structures (1, 40) and of supplying a user (308) with an indication dependent on the probability of damage thus estimated.