Hydrogen Buffer Tank Supply Circuit for Fuel Cell Shutdown Reserve
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Solution Overview
Problem
Fuel cell systems face challenges in maintaining optimal hydrogen pressure, as existing liquid hydrogen storage facilities operate at low pressures, leading to reduced filling levels and endurance, and require additional tanks for safe shutdown, resulting in higher hydrogen consumption and complexity.
Innovation Solution
Incorporating a buffer tank for pressurized gaseous hydrogen in the supply circuit, configured to store hydrogen at a higher pressure (between 4 and 100 bar) to maintain a reserve for safe shutdown and self-pressurization, while allowing the storage facility to operate at a lower pressure, with a system of valves and heat exchangers to manage pressure and flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid hydrogen storage facility operates at low pressure, then safety and structural integrity are improved, but filling level and endurance are reduced
Solution Approach 1:
The system is divided into two distinct storage facilities: a first liquid hydrogen storage facility operating at low pressure (1.5-4.5 bar) for safety and structural integrity, and a second gaseous hydrogen storage facility operating at high pressure (350-700 bar) for endurance and filling level. This segmentation allows each facility to operate at its optimal pressure range without compromise.
Solution Approach 2:
A pressure regulation system acts as an intermediary between the two storage facilities, enabling hydrogen to be transferred from the low-pressure liquid storage to the high-pressure gaseous storage. This intermediary mechanism resolves the contradiction by facilitating pressure transformation while maintaining safety in both facilities.
2Reliability
If additional tanks are added for safe shutdown, then safety is improved, but device complexity and hydrogen consumption increase
Solution Approach 1:
The second gaseous hydrogen storage facility serves multiple functions: it acts as a high-pressure storage for endurance extension and simultaneously serves as a safety reserve for unexpected shutdowns. This multi-functionality eliminates the need for separate dedicated safety tanks, reducing overall system complexity while maintaining safety capabilities.
Solution Approach 2:
The safety reserve function is merged with the high-pressure storage function in the second facility. Instead of having separate tanks for safety and endurance, the system combines these functions into a single gaseous storage facility, thereby reducing the total number of tanks and simplifying the overall system architecture.
3Duration of action of moving object
If hydrogen is stored at high pressure, then filling level and endurance are improved, but pressure regulation complexity increases
Solution Approach 1:
The pressure regulation system is designed to be dynamic and adaptive, automatically adjusting pressure levels based on the operational state of the fuel cell and the hydrogen demand. This dynamic regulation simplifies operation compared to static high-pressure systems, as the system self-adjusts to maintain optimal pressure without requiring complex manual intervention or oversized regulation equipment.
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 enables safe and efficient operation of fuel cells by maintaining a hydrogen reserve for unexpected shutdowns, reducing hydrogen consumption, and extending the endurance of the storage facility while minimizing the need for additional tanks.
Implementation Method 1
a supply circuit comprising at least one system (5, 15) for heating hydrogen by heat exchange with a heat source
Implementation Method 2
liquid hydrogen expands as its liquid/gas saturation pressure increases
Implementation Method 3
liquid hydrogen expands as its liquid/gas saturation pressure increases
Implementation Method 4
Such a tank naturally self-pressurizes via the thermal inputs (insulation, pipelines, supports) when no flow of product is withdrawn
Implementation Method 5
The two isolation valves (11, 12) are closed and trap the cold gas in the buffer storage facility (7), which self-pressurizes
Data Source
AI summary
An installation for supplying a fuel cell with hydrogen comprising a fuel cell, a liquefied hydrogen storage facility and a supply circuit that includes at least one upstream end connected to the storage facility and one downstream end connected to a fuel inlet of the fuel cell, the supply circuit including at least one system for heating hydrogen by heat exchange with a heat source and a set of control valves, the liquefied hydrogen storage facility being configured to keep the liquefied hydrogen in equilibrium with a gaseous phase at a determined nominal storage pressure of between 1.5 and 4.5 bar, the supply circuit including a buffer tank for pressurized gaseous hydrogen which is configured to store the hydrogen withdrawn from the storage facility and heated by the heating system, the set of valves being configured to accumulate pressurized gas in the buffer tank at a determined storage pressure of between 4 and 100 bar, for example between 6 and 8 bar.