Supercritical Hydrogen Conveying Device for Maritime Stability
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Solution Overview
Problem
Existing methods for conveying cryogens, such as liquid hydrogen, in maritime environments face challenges in maintaining stable operating conditions due to sea wave movements, and they often require maintenance for cryopumps with moving parts or are energetically unfavorable.
Innovation Solution
A method involving a series of conditioning vessels where the cryogen is brought into a supercritical state by introducing heat, allowing for the venting of a gaseous phase to transfer heat back to the cryogen, thereby maintaining the supercritical state during discharge and reducing the need for high-pressure storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cryogen is stored in a storage tank with a pressure build-up evaporator, then gaseous hydrogen can be made available at a stable supply pressure, but sea wave movements make it very difficult to maintain the operating conditions stable
Solution Approach 1:
The system is divided into multiple conditioning vessels (first conditioning vessel, second conditioning vessel) that can operate alternately. This segmentation allows one vessel to be in the supercritical state while another is being filled, ensuring continuous stable supply while isolating the storage tank from wave-induced disturbances.
Solution Approach 2:
The cryogen is transformed from liquid to supercritical state by changing pressure and temperature parameters in the conditioning vessels. This parameter change eliminates the phase boundary, making the cryogen incompressible and immune to wave-induced volume changes, thus maintaining stable supply pressure.
2Reliability
If a cryopump is used to pump hydrogen from storage container to fuel cell, then the required supply pressure can be achieved, but the moving parts require maintenance and lead to downtime
Solution Approach 1:
The mechanical cryopump system is replaced with a thermodynamic system using conditioning vessels that utilize phase change and supercritical fluid properties. This substitution eliminates moving parts entirely, achieving the required supply pressure through thermal and pressure field manipulation rather than mechanical pumping.
Solution Approach 2:
The system utilizes phase transitions of hydrogen (liquid to supercritical to gaseous) to achieve pressure regulation and delivery. The phase change process naturally provides the necessary pressure differential without requiring mechanical pumps, eliminating maintenance requirements.
3Reliability
If hydrogen is evaporated upstream of the fuel cell and then compressed to achieve required supply pressure, then the supply pressure can be maintained, but the process is energetically unfavorable
Solution Approach 1:
The cryogen is pre-conditioned in the conditioning vessels to reach the supercritical state before delivery to the fuel cell. This preliminary action of heating and pressurizing in a controlled environment is more energy-efficient than evaporating and then compressing, as the supercritical state is achieved through optimized thermal processes rather than high-energy compression.
Solution Approach 2:
The system changes the thermodynamic parameters of hydrogen to reach a supercritical state directly, which is energetically more favorable than the evaporate-then-compress pathway. The supercritical state provides a direct route to the required supply pressure without the energy-intensive compression step.
4Duration of action of stationary object
If the storage vessel is operated at high pressure to extend cryogen holding time, then the cryogen can be stored longer, but the complexity of the system increases
Solution Approach 1:
The storage system is segmented into the storage tank and multiple conditioning vessels. This allows the storage tank to operate at low pressure (simplifying its design) while the conditioning vessels handle the high-pressure supercritical state temporarily. The segmentation distributes the complexity across separate functional components.
Solution Approach 2:
The conditioning vessels act as intermediaries between the low-pressure storage tank and the high-pressure fuel cell consumer. These intermediate vessels manage the pressure transition and supercritical state, allowing the storage tank to remain simple while still enabling extended holding time through the intermediary conditioning process.
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 stabilizes the temperature distribution within the conditioning vessels, reduces maintenance needs, and extends the cryogen's holding time, allowing for a smaller heating element and more efficient energy use.
Implementation Method 1
introducing heat into the cryogen contained in the first conditioning vessel, thereby bringing the cryogen into its supercritical state
Implementation Method 2
during step c) heat is transferred from the gaseous phase to the cryogen contained in the first conditioning vessel
Implementation Method 3
the cryogen contained in the first conditioning vessel is maintained in the supercritical state during step d)
Data Source
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AI summary
A method for conveying a cryogen (H2) from a storage container (2) to a consumer (3), comprising the following steps: a) introducing (S1) the cryogen (H2) from the storage container (2) into a first conditioning container (8), b) introducing (S2) heat (Q) into the cryogen (H2) received in the first conditioning container (8), whereby the cryogen (H2) is brought into its supercritical state, c) blowing off (S3) a gaseous phase (GH2) of the cryogen (H2) from a second conditioning container (9) into the storage container (2), wherein steps b) and c) are carried out simultaneously, and wherein during step c) heat (Q) is transferred from the gaseous phase (GH2) to the cryogen (H2) received in the first conditioning container (8), and d) discharging (S4) the cryogen (H2) from the first conditioning container (8) to the Consumers (3),wherein the cryogen (H2) contained in the first conditioning vessel (8) is kept in the supercritical state during step d).