Liquefied Gas Tank Cooling Loop for Pressure Rise Suppression
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Solution Overview
Problem
The complexity and cost of installing both LPG and LNG reliquefaction systems on a single vessel lead to increased equipment complexity and costs, with existing methods failing to effectively suppress pressure rises in storage tanks storing liquefied gases.
Innovation Solution
A storage-tank pressure-rise suppressing apparatus that uses a heat exchange system with a refrigerant to cool liquefied gas, reducing the need for multiple systems by employing a single-phase heat exchange and refrigerant compression, thereby simplifying equipment and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both LPG and LNG reliquefaction systems are installed on a single vessel, then pressure rise suppression capability is improved, but device complexity and equipment costs increase
Solution Approach 1:
The patent creates a unified reliquefaction system that can handle both LPG and LNG boil-off gases using a single apparatus. The system uses a refrigerant cycle with adjustable parameters to accommodate different gas types, eliminating the need for separate LPG and LNG reliquefaction systems while maintaining pressure suppression capability for both gas types.
Solution Approach 2:
The system employs parameter changes in the refrigerant cycle to adapt to different refrigeration requirements of LPG and LNG. By adjusting refrigerant flow rates, compression ratios, and heat exchange parameters, the single system can effectively reliquefy both LPG (which requires lower temperatures) and LNG (which requires higher temperatures), resolving the contradiction between system universality and performance effectiveness.
2Reliability
If both LPG and LNG reliquefaction systems are installed on a single vessel, then pressure rise suppression capability is improved, but equipment costs increase
Solution Approach 1:
The patent merges the functionality of separate LPG and LNG reliquefaction systems into a single integrated apparatus. By combining compressors, heat exchangers, and refrigerant cycles into one system that can serve both gas types, the equipment cost is reduced while maintaining the pressure suppression capability for both LPG and LNG storage tanks.
Solution Approach 2:
The unified system provides multi-functional capability to handle both LPG and LNG reliquefaction, eliminating the need for duplicate equipment investments. The system achieves cost-effectiveness by using a single apparatus with adjustable parameters rather than maintaining two separate specialized systems.
3Reliability
If liquid-phase liquefied gas is cooled by exchanging heat with refrigerant, then pressure rise suppression is improved, but refrigerant compression ratio increases
Solution Approach 1:
The system optimizes refrigerant compression parameters by adjusting the refrigerant cycle operating conditions. Through parameter optimization in the refrigerant flow rate, compression pressure, and heat exchange temperature differences, the system achieves effective pressure rise suppression while minimizing the compression ratio and associated energy consumption.
Solution Approach 2:
The refrigerant system operates continuously to maintain steady-state cooling of the liquid-phase liquefied gas. This continuous operation allows for optimized compression parameters and efficient heat exchange, reducing peak compression ratios and overall energy consumption compared to intermittent operation modes.
4Reliability
If conventional reliquefaction systems are used, then pressure rise suppression is achieved, but equipment complexity increases
Solution Approach 1:
The patent replaces multiple conventional specialized reliquefaction systems with a single universal system that can handle both LPG and LNG. This unified approach reduces system complexity by eliminating redundant components while maintaining the pressure suppression function through parameter-adjustable refrigerant cycles.
Solution Approach 2:
The system merges the functionality of separate LPG and LNG reliquefaction apparatus into one integrated system. By combining compressors, heat exchangers, and control mechanisms into a unified configuration, the patent reduces overall system complexity while achieving pressure rise suppression for both gas types through coordinated 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
This solution effectively suppresses pressure rises in storage tanks by cooling liquefied gas without phase change, reducing refrigerant compression ratios, improving heat exchange efficiency, and allowing for a compact design, thus simplifying the apparatus and reducing equipment costs.
Implementation Method 1
heat exchange means for exchanging heat between the liquid-phase liquefied gas extracted from the storage tank and a refrigerant
Implementation Method 2
employing a single-phase heat exchange and refrigerant compression
Implementation Method 3
refrigerant compression means for compressing the refrigerant that is to be fed to the heat exchange means
Implementation Method 4
refrigerant expansion means for reducing the pressure of the refrigerant that has been compressed by the refrigerant compression means
Implementation Method 5
the liquid-phase liquefied gas that has been cooled in the heat exchange means is fed to the liquid-phase liquefied gas in the storage tank
Data Source
Figure 1
Figure 2
Figure 3(A)~3(B)
AI summary
In order to suppress pressure rise in a storage tank for storing liquefied gas, simplify a facility and lower the cost of the facility, a pressure rise suppression device for a storage tank is provided with: the storage tank (2) in which liquefied gas is stored; a heat exchange means (4) in which the liquefied gas in a liquid state extracted from the storage tank (2) and a refrigerant exchange heat with seach other; a refrigerant compression means (31) which compresses the refrigerant led to the heat exchange means (4); a refrigerant expansion means (33) which reduces the pressure of the refrigerant compressed by the refrigerant compression means (31) and supplies the refrigerant to the heat exchange means (4), and a supply means (11) which supplies the liquefied gas in the liquid state cooled in the heat exchange means (4) to the liquefied gas in the liquid state in the storage tank (2).