Ionic Liquid Displacement for Constant Pressure Hydrogen Storage
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Solution Overview
Problem
The storage of gaseous hydrogen at fueling stations is hindered by its low density, requiring large volumes and space, and current methods result in 'stranded' gas and inefficient filling rates due to high pressure differentials and multi-step conversion processes.
Innovation Solution
Employing ionic liquids to maintain constant storage pressure, displacing volume in tanks and eliminating stranded gas, allowing for reduced tank numbers and enabling complete and fast vehicle filling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If gaseous hydrogen is stored in large volumes to provide sufficient inventory, then the hydrogen availability is improved, but the storage footprint increases
Solution Approach 1:
The patent changes the physical state of hydrogen from gaseous to liquid by cooling it to cryogenic temperatures (below -253°C). This phase change increases the density of hydrogen by a factor of about 800, allowing much larger quantities of hydrogen to be stored in the same volume, thereby providing sufficient inventory without increasing the storage footprint.
2Quantity of substance
If high pressure is used to achieve full fill density, then the vehicle filling completeness is improved, but the amount of stranded gas increases
Solution Approach 1:
The patent utilizes phase transition between liquid and gaseous hydrogen. Liquid hydrogen is stored in the tanks and vaporized on-demand to maintain constant pressure. This eliminates the need for large volumes of low-pressure stranded gas because the liquid phase occupies minimal volume and can be vaporized as needed to achieve full fill density without leaving unusable low-pressure residual gas.
Solution Approach 2:
The system dynamically adjusts the vaporization rate of liquid hydrogen to maintain constant pressure in the storage tanks. A controlled vaporization process ensures that hydrogen is converted from liquid to gas at a rate that matches dispensing demands, preventing pressure buildup and eliminating the need for excessive low-pressure gas inventory that would otherwise be required.
3Ease of operation
If pressure equalization is used to fuel vehicles, then the fueling process is simplified, but the fueling rate decreases
Solution Approach 1:
The patent employs rapid vaporization of liquid hydrogen to generate high-pressure gaseous hydrogen on-demand. This phase transition occurs quickly and can be controlled to deliver hydrogen at high rates, enabling fast fueling while maintaining the simplicity of pressure-driven flow into the vehicle tank.
Solution Approach 2:
The system dynamically controls the vaporization process to match fueling demands. By adjusting the heat input to the liquid hydrogen, the system can rapidly generate high-pressure gas when a vehicle is being fueled, then reduce vaporization rate when fueling is complete, thereby maintaining high fueling rates without requiring excessively high storage pressures.
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 storage costs and size, ensures full and fast vehicle filling by maintaining constant pressure, and increases usable hydrogen inventory while minimizing the need for multiple storage tanks.
Implementation Method 1
The ionic liquid is used to displace the volume in the storage tanks. By displacing the volume in the storage tanks with the ionic liquid, the storage pressure can remain constant
Data Source
AI summary
In the present invention methods for storing gaseous hydrogen employing an ionic liquid are disclosed. The ionic liquid is used to displace the volume in the storage tanks. By displacing the volume in the storage tanks with the ionic liquid, the storage pressure can remain constant and the “stranded” gas can be eliminated. This constant pressure will also allow for a reduction in the number of storage tanks needed to provide the required inventory at hydrogen fueling stations. In addition, this constant pressure will provide a complete and fast fill to the vehicle.