Liquefied Hydrogen Storage With Dual-Temperature Boil-Off Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liquefied hydrogen storage technologies face challenges in controlling the irregular generation of boil-off gas due to ortho-para conversion, leading to high storage pressures and inefficiencies, which affect the capacity and safety of storage tanks.
Innovation Solution
A system with two storage tanks operating in high-temperature and low-temperature modes, utilizing heat transfer and phase change to control boil-off gas generation, recover cold heat, and convert it into electric power, maintaining tanks at low pressures and stabilizing hydrogen storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If liquefied hydrogen is stored using typical LNG storage technologies, then storage capacity is increased, but storage pressure becomes excessively high (3 bar or more)
Solution Approach 1:
The patent applies parameter changes by controlling the temperature of liquefied hydrogen to be above its triple point temperature (20.3K), thereby changing the physical state parameters to reduce storage pressure to below 3 bar while maintaining adequate storage capacity. This temperature parameter control allows the system to operate in a pressure range that meets both storage capacity requirements and safety standards.
2Loss of energy
If insulation thickness is increased to reduce storage pressure, then thermal insulation is improved, but device complexity and construction difficulty increase
Solution Approach 1:
Instead of increasing insulation thickness, the patent changes the temperature parameter of the stored hydrogen to be above the triple point. This parameter change fundamentally alters the pressure-temperature relationship, allowing adequate thermal insulation to be achieved with conventional insulation thicknesses, thereby reducing device complexity and construction difficulty.
3Reliability
If storage pressure is reduced to meet safety standards, then safety is improved, but storage capacity decreases
Solution Approach 1:
The patent resolves this contradiction by changing the temperature parameter to maintain hydrogen above its triple point temperature. This parameter change creates a new operating window where storage pressure is reduced to below 3 bar (improving safety) while storage capacity is maintained at adequate levels through optimized tank design for the new operating conditions.
4Stress or pressure
If boil-off gas is discharged to control pressure, then storage pressure is maintained, but energy loss increases
Solution Approach 1:
The patent converts the harmful effect of boil-off gas (energy loss) into a beneficial effect by using it for cooling purposes. The boil-off gas is directed to cool the liquid hydrogen, particularly during filling operations or when temperature control is needed. This converts what would be wasted energy into a useful cooling resource, reducing overall energy loss while maintaining pressure control.
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 effectively manages boil-off gas generation, reduces storage pressure, increases tank capacity, and ensures stable hydrogen supply for fuel cells, enhancing safety and efficiency during transportation and storage.
Implementation Method 1
a heat transfer medium circulation unit transferring cold heat from the high-temperature tank to the low-temperature tank
Implementation Method 2
the first temperature is a first temperature at which at least a portion of the liquefied hydrogen is solidified
Implementation Method 3
the second temperature is a second temperature exceeding a triple point of the liquefied hydrogen
Implementation Method 4
the generated boil-off gas is used to produce electric power
Data Source
AI summary
Disclosed herein are a system and method which can control the generation rate of boil-off gas from liquefied hydrogen and can maintain the liquefied hydrogen storage tank at a low pressure. The method for controlling boil-off gas from liquefied hydrogen according to the present invention includes: at least two storage tanks storing liquefied hydrogen and each operated in a high-temperature mode or in a low-temperature mode, wherein the low-temperature mode includes: maintaining at least a portion of liquefied hydrogen stored in the storage tank at a first temperature being a densification temperature, and the high-temperature mode includes: maintaining at least a portion of liquefied hydrogen stored in the storage tank at a second temperature being a temperature exceeding a triple point of liquefied hydrogen through recovery of cold heat from liquefied hydrogen stored in the storage tank.