Gas Supply System Pre-Cooling for Faster High-Pressure Start-Up
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Solution Overview
Problem
Existing gas supply systems for vessels with ME-GI propulsion engines require expensive high-pressure compressors that induce vibrations and have high maintenance costs, and the pre-cooling process for large elements delays the start-up of the gas supply system.
Innovation Solution
A gas supply system with a pre-cooling system for the first heat exchanger, a bypass circuit, and a cooling system for the second pump, which increases the gas flow rate through the heat exchanger and pump to rapidly bring them to operating temperature, reducing the time required for system start-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a high-pressure compressor is installed to supply gas to the propulsion engine, then the gas can be compressed to 300 bars for ME-GI engine operation, but the system becomes expensive with high maintenance costs and vibrations
Solution Approach 1:
The patent removes the high-pressure compressor from the system entirely. Instead, it uses a pressure reduction valve to step down pressure from the storage tank (300 bar) to the engine operating pressure (200 bar), and a low-pressure compressor only for boil-off gas management. This extraction of the problematic high-pressure compressor eliminates vibrations and maintenance issues while maintaining the required pressure for ME-GI engine operation.
Solution Approach 2:
The patent introduces a pressure reduction valve as an intermediary device between the high-pressure storage tank and the ME-GI engine. This mediator component handles the pressure reduction function that would otherwise require a high-pressure compressor, thereby avoiding the negative effects of high-pressure compression while still delivering the necessary operating conditions to the engine.
2Temperature
If large elements like heat exchangers are pre-cooled before operation, then the system can operate efficiently, but the start-up time is delayed due to the lengthy pre-cooling process
Solution Approach 1:
The patent applies preliminary cooling action by circulating cold liquid through the heat exchanger before operation begins. The system includes a cooling circuit that pre-cools the heat exchanger using cold liquid from the LNG tank, preparing the heat exchanger for efficient operation before gas flow begins. This preliminary action reduces the thermal mass that needs to be cooled during actual operation, thereby reducing start-up time.
Solution Approach 2:
The heat exchanger pre-cooling system uses the cold LNG already present in the storage tank as the cooling medium. The system serves itself by utilizing its own stored cold energy to pre-cool the heat exchanger, eliminating the need for external cooling sources and reducing the overall start-up time while maintaining efficient operation.
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 system reduces the time needed to bring large elements up to temperature, allowing for faster start-up of the gas supply system and avoids the need for costly high-pressure compressors, while maintaining efficient operation.
Implementation Method 1
at least one first pump configured to pump the gas taken from the tank in the liquid state
Implementation Method 2
at least one first heat exchanger, a second heat exchanger... the gas in the liquid state passes through the first heat exchanger and then the second heat exchanger
Implementation Method 3
the second pump allows to increase the pressure of the gas in the liquid state circulating in the first supply circuit
Implementation Method 4
at least one high-pressure evaporator configured to evaporate the gas circulating in the first gas supply circuit
Implementation Method 5
the gas circulating in the first supply circuit may be in a two-phase state at the outlet of the second heat exchanger
Implementation Method 6
at least one compressor configured to compress gas taken in the vapor state from the tank to an operating pressure of the appliance consuming low-pressure gas
Implementation Method 7
the pre-cooling system comprises a pre-cooling line connected to the first supply circuit between the first heat exchanger and the second pump
Data Source
AI summary
A gas supply system supplies gas to an appliance consuming high-pressure gas of a floating structure including at least one tank. The gas supply system includes at least one first supply circuit for supplying the high-pressure consumer appliance, including a first heat exchanger, a second heat exchanger, and a pump. The gas supply system also includes a pre-cooling system for pre-cooling the first heat exchanger to take gas in the liquid state from the tank. The pre-cooling system includes a pre-cooling line and a control valve for controlling the circulation of gas within the pre-cooling line.