Liquid Loading Assembly for Ship-Hold Filling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for loading oil onto tank ships result in excessive emissions of Volatile Organic Compounds (VOC) due to flashing in the cargo transfer pipe system, particularly caused by the siphon effect in vertical oil supply conduits, which leads to pressure reduction and increased VOC release.
Innovation Solution
A liquid loading assembly with a flow control valve on the outlet of the vertical dropline reduces the oil supply conduit's drop height, minimizing the siphon effect and VOC emissions, and incorporates a gas/liquid separation device to remove gas bubbles, ensuring vapors face increased hydrostatic pressure before escaping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional vertical dropline is used to transfer oil from deck level to cargo tanks, then oil loading efficiency is improved, but VOC emissions increase due to siphon effect and pressure reduction
Solution Approach 1:
A liquid intermediary (water or inert liquid) is introduced into the dropline to act as a mediator between the incoming oil and the cargo tank atmosphere. This intermediary liquid absorbs the kinetic energy of incoming oil, prevents direct contact with tank atmosphere, and maintains pressure to prevent VOC flashing and emissions while preserving loading efficiency
2Productivity
If the oil supply conduit drop height is increased to improve loading speed, then productivity increases, but the siphon effect intensifies causing greater pressure reduction and VOC release
Solution Approach 1:
The liquid intermediary fills the dropline to create a liquid seal that prevents the siphon effect from developing. By introducing this intermediary liquid, the system can maintain larger drop heights for faster loading while the intermediary absorbs pressure fluctuations and prevents vacuum formation that would cause VOC flashing
3Object-generated harmful factors
If the dropline is filled with liquid to reduce siphon effect, then VOC emissions are reduced, but device complexity increases due to flow control valve and liquid level management
Solution Approach 1:
The flow control valve is designed to automatically regulate liquid level in the dropline based on flow conditions, eliminating the need for external control systems. The system self-regulates by using the flow characteristics of incoming oil to automatically maintain the liquid intermediary at the optimal level, reducing operational complexity
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
The solution significantly reduces VOC emissions by minimizing the siphon effect and bubble formation, maintaining a higher liquid level in the dropline, and utilizing a gas/liquid separation device to capture gas bubbles, thereby decreasing VOC release during oil loading operations.
Implementation Method 1
From the point in time when the supply conduit becomes submerged in oil, vapour released at the top of the vertical oil supply conduit will have to overcome hydrostatic pressure in the conduit outlet in order to pass through.
Implementation Method 2
Oil in the vertical part of the oil supply conduit is accelerated by gravity, which causes a siphon effect that leads to an undesired pressure reduction in the upper part of the conduit.
Implementation Method 3
By combining the disclosed embodiments of a liquid loading assembly with a gas/liquid separation device (commercially available technology, and not part of the invention), a large portion of gas bubbles generated in the oil supply conduit before the dropline may also be removed from the oil in the supply conduit
Implementation Method 4
Oil in the vertical part of the oil supply conduit is accelerated by gravity
Data Source
AI summary
A liquid loading assembly for filling a ship-hold or tank with a volatile liquid, includes an oil supply conduit, fluidly connected to the tank, the outlet end of said conduit extending vertically within a dropline. The dropline extends from a lower dropline end positioned below the outlet end of the oil supply conduit to an upper dropline end positioned above the outlet end of the oil supply conduit, the lower dropline end being at least partially closed by a valve. The valve is arranged to open gradually up to a maximum aperture in response to one of i) increased pressure on the valve and ii) a level of liquid above the valve.