Liquid Hydrogen Tank Filling With Subcooled Pre-Cooling
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Solution Overview
Problem
Conventional methods for filling liquid hydrogen tanks face significant evaporation losses due to the low density and low pressure of liquid hydrogen, leading to inefficient transfer and increased energy consumption, as well as the need for additional systems to recirculate boil-off gases.
Innovation Solution
A method involving a two-stage transfer process, where the first stage uses subcooled liquid hydrogen from a liquefier to lower the tank's temperature and pressure, followed by a second stage that utilizes a pressure difference between the storage facility and the tank to fill the tank, with optional depressurization phases to manage initial conditions and minimize evaporation losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid hydrogen is transferred by pressure difference to increase filling speed, then productivity is improved, but evaporation losses increase due to vaporization in valves and piping
Solution Approach 1:
The tank is pre-cooled with liquid hydrogen before the main filling operation. This preliminary action lowers the tank temperature to reduce thermal gradient and minimize vaporization during subsequent filling, thereby reducing evaporation losses while maintaining efficient filling speed
Solution Approach 2:
The invention changes the temperature parameter of the liquid hydrogen used for pre-cooling. By using liquid hydrogen at a temperature lower than the storage temperature (e.g., -253°C vs -243°C), it creates a thermal sink that absorbs heat during transfer, reducing vaporization losses while enabling faster filling
2Device complexity
If liquid hydrogen is transferred by gravity to reduce equipment complexity, then device complexity is reduced, but productivity decreases due to low density of liquid hydrogen
Solution Approach 1:
Liquid hydrogen acts as an intermediary cooling medium. A small amount of liquid hydrogen is introduced into the tank to cool it, creating a cold environment that reduces vaporization. This intermediary substance enables faster filling by pressure difference without proportionally increasing evaporation losses
3Ease of operation
If conventional filling methods are used to simplify the process, then ease of operation is improved, but energy consumption increases due to boil-off gas recirculation requirements
Solution Approach 1:
The invention converts the harmful effect of cold liquid hydrogen contact with warm tank walls (which causes vaporization) into a beneficial effect. By intentionally introducing liquid hydrogen for pre-cooling, the vaporization that would otherwise be a loss is used to cool the tank and reduce overall evaporation during filling, eliminating the need for energy-consuming recirculation systems
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 approach reduces evaporation losses by up to a factor of eight to ten compared to conventional methods, eliminates the need for boil-off gas recirculation systems, and optimizes energy consumption, while maintaining a stable storage pressure and temperature.
Implementation Method 1
a first stage of transfer of a first amount of subcooled liquid hydrogen into the tank from a first source of liquid hydrogen comprising a hydrogen liquefier, the first amount of subcooled liquid hydrogen being provided in order to lower the temperature and the pressure in the tank
Implementation Method 2
a second stage of transfer of a second amount of liquid hydrogen into the tank from a second source of liquid hydrogen comprising a liquid hydrogen storage facility, in which the second amount of liquid hydrogen is transferred into the tank by pressure difference between the liquid hydrogen storage facility and the tank
Data Source
AI summary
The invention relates to a method for storing and distributing liquefied hydrogen using a facility that comprises a store of liquid hydrogen at a predetermined storage pressure, a source of hydrogen gas, a liquefier comprising an inlet connected to the source and an outlet connected to the liquid hydrogen store, the store comprising a pipe for drawing liquid, comprising one end connected to the liquid hydrogen store and one end intended for being connected to at least one mobile tank, the method comprising a step of liquefying hydrogen gas supplied by the source and a step of transferring the liquefied hydrogen into the store, characterized in that the hydrogen liquefied by the liquefier and transferred into the store has a temperature lower than the bubble temperature of hydrogen at the storage pressure.