LNG Fuel Supply System Dual Return Lines Overpressure
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Solution Overview
Problem
Existing LNG fuel supply systems for ships face overpressure issues when the engine suddenly stops, leading to potential system shutdowns due to uncontrolled pressure increases in the fuel supplying line.
Innovation Solution
A system with a pressure measuring sensor and dual return lines that allow fuel to be returned to the storage tank through a first and second return line, preventing overpressure by adjusting the fuel supply through upstream and downstream overpressure valves, and including a heat exchanger and pump configuration to manage pressure and temperature effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single return line is used to return fuel from the fuel supplying line, then the system structure is simple, but overpressure cannot be effectively prevented when the engine stops suddenly
Solution Approach 1:
The single return line is segmented into two separate return lines: a first return line connected to the upstream side of the heat exchanger and a second return line connected to the downstream side. This segmentation allows independent pressure control at different locations, enabling effective overpressure prevention while maintaining systematic simplicity.
Solution Approach 2:
Overpressure valves are introduced as intermediary devices on the return lines. These valves act as mediators that automatically open when pressure exceeds predetermined thresholds, releasing excess fuel and preventing overpressure without requiring complex control systems.
2Reliability
If fuel supply pressure is increased to ensure adequate fuel delivery to the engine, then fuel delivery reliability is improved, but the risk of overpressure when the engine stops increases
Solution Approach 1:
The system applies preliminary anti-action by providing return lines with overpressure valves that are prepared in advance to counteract potential overpressure. When the engine stops suddenly, these pre-configured pathways immediately become active to release pressure, preventing the harmful effect before it can cause damage.
Solution Approach 2:
The system changes the pressure parameter dynamically by allowing fuel to flow back through the return lines when pressure exceeds predetermined thresholds. The overpressure valves are set to open at specific pressure levels, automatically adjusting the system pressure to safe levels without affecting normal fuel delivery pressure during engine operation.
3Adaptability or versatility
If the engine stops suddenly during fuel supply, then operational flexibility is improved, but uncontrolled pressure increase occurs in the fuel supplying line
Solution Approach 1:
The system implements feedback control through pressure sensors that continuously monitor fuel line pressure and provide information to the overpressure valves. When pressure exceeds the predetermined threshold after engine stop, the feedback signal triggers the overpressure valve to open, releasing fuel through the return line and reducing pressure back to safe levels.
Solution Approach 2:
The return line system provides dynamic pressure management by allowing the system to adapt its pressure characteristics based on operational conditions. During normal operation, the system maintains high pressure for reliable fuel delivery. When the engine stops, the system dynamically switches to pressure relief mode through the return lines, preventing uncontrolled pressure increase.
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
Prevents overpressure at the engine and upstream components, reducing the risk of system shutdowns caused by sudden engine stops or other failures, ensuring safe and reliable operation.
Implementation Method 1
a pressure measuring sensor (23) provided on the fuel supplying line (21)
Implementation Method 2
a pump (30) provided on the fuel supplying line (21) and configured to pressurize fuel outputted from the fuel storage tank (10)
Implementation Method 3
a heat exchanger (50) provided on the fuel supplying line (21) between the pump (30) and the engine (20) and configured to heat the fuel outputted from the pump (30)
Implementation Method 4
an upstream overpressure valve (112) provided on the first return line (111), and configured to adjust an amount of supply of the fuel; and a downstream overpressure valve (114) provided on the second return line (113), and configured to adjust an amount of supply of the fuel
Data Source
AI summary
A system (1) for supplying fuel includes a fuel supplying line (21) connected from a fuel storage tank (10) to an engine (20) and including a pressure measuring sensor (23), a pump (30) provided on the fuel supplying line and configured to pressurize fuel outputted from the fuel storage tank (10), a heat exchanger (50) provided on the fuel supplying line (21) between the pump (30) and the engine (20) and configured to heat the fuel outputted from the pump (30), a first return line (11)provided at a front end of the heat exchanger on the fuel supplying line (21) and configured to return the fuel from the fuel supplying line (21), and a second return line (113) provided at a rear end of the heat exchanger (50) on the fuel supplying line (21) and configured to return the fuel from the fuel supplying line (21).