Removable LNG Tank for Rapid Marine Vessel Bunkering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The slow bunkering process of LNG fuelled marine vessels due to temperature differences causing two-phase flow and pressure pulses in the bunkering line, leading to low flow rates and extended refuelling times, which is incompatible with modern operational demands of short port times and high energy consumption.
Innovation Solution
Implementing a dual LNG storage system comprising a fixed and a removable LNG storage tank, allowing for continuous LNG supply and rapid tank replacement at sea, enabling efficient LNG transfer and reducing bunkering time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LNG is supplied at a high flow rate to reduce bunkering time, then productivity is improved, but pressure pulses and two-phase flow cause harmful effects on the bunkering line
Solution Approach 1:
The invention divides the bunkering operation into two independent stages: first transferring LNG from the bunkering vessel to an intermediate storage tank on the marine vessel, then transferring from the intermediate tank to the fixed LNG storage tank. This segmentation allows the first transfer to use high flow rates without causing pressure pulses in the final supply line, as the intermediate tank acts as a buffer that decouples the high-speed transfer from the sensitive fuel supply system.
2Object-affected harmful factors
If the flow rate is kept low to minimize pressure pulses, then harmful effects are reduced, but bunkering time increases significantly
Solution Approach 1:
The invention introduces an intermediate storage tank as a mediator between the bunkering line and the fixed LNG storage tank. This intermediary tank receives LNG at high flow rates during the initial transfer phase, then supplies it gradually to the fixed tank, thereby eliminating pressure pulses while enabling fast bunkering. The intermediate tank absorbs the shock of high flow rates and provides a controlled supply to the fuel system.
3Device complexity
If a single fixed LNG storage tank is used, then device complexity is reduced, but the ability to perform rapid refuelling is limited
Solution Approach 1:
The invention segments the storage system into a fixed LNG storage tank for long-term storage and a removable intermediate storage tank for rapid transfer operations. This segmentation enables the system to achieve both simplicity (through the fixed tank) and high productivity (through the removable tank that can be quickly exchanged at the bunkering facility).
Solution Approach 2:
The invention makes the intermediate storage tank removable and exchangeable, introducing dynamic flexibility to the otherwise static fixed storage tank system. This dynamic element allows the intermediate tank to be pre-filled at the bunkering facility and quickly swapped onto the marine vessel, enabling rapid refuelling without requiring complex piping modifications or lengthy connection procedures.
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
This approach significantly reduces bunkering time, keeping the marine vessel operational with minimal interruptions, especially beneficial for vessels like offshore support vessels and tugs that require constant availability.
Implementation Method 1
The reason for this is the temperature difference between LNG (normally about −162° C.) and the bunkering line (normally in ambient temperature, around +20° C.). This temperature difference causes the LNG to boil in the bunkering line, which leads to a two-phase flow of gas and liquid.
Implementation Method 2
The removable LNG storage tank is connected to the fixed LNG storage tank when the removable LNG storage tank is deployed on the marine vessel, whereby LNG can be transferred from the removable LNG storage tank to the fixed LNG storage tank
Data Source
AI summary
A method for operating an LNG fuelled marine vessel having a propulsion system, a power plant and an LNG storage tank, whereby LNG is supplied as a gas fuel from the LNG storage tank to the power plant. The marine vessel deploys a fixed LNG storage tank and a removable LNG storage tank on board the marine vessel. In order to facilitate bunkering, the removable LNG storage tank is removed and replaced by another removable LNG storage tank at a bunkering facility.