Hydrogen Recirculation and Purification for Fuel Cell Efficiency
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Solution Overview
Problem
Conventional fuel cell systems face issues with hydrogen excess, impurity accumulation, and material degradation due to oxygen and hydrogen presence when not in use, leading to inefficiencies and increased costs.
Innovation Solution
A hydrogen recirculation and purification device that includes a hydrogen supply unit, a purification and compression unit using a membrane-electrode assembly for electrochemical purification, and a gas storage tank, which separates and stores inert gases to purge the fuel cell compartments, reducing hydrogen overconsumption and material degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If excess hydrogen (5-20% more than ideal consumption) is supplied to ensure uniform distribution and optimal performance, then fuel cell performance is improved, but hydrogen overconsumption and energy loss increase
Solution Approach 1:
The patent recovers unused hydrogen from the anode outlet and recirculates it back to the inlet, preventing hydrogen waste. The system captures the excess hydrogen that would otherwise be discarded and reuses it, thereby reducing overall hydrogen consumption while maintaining the performance benefits of excess hydrogen supply.
Solution Approach 2:
The recirculation system operates continuously to maintain optimal hydrogen distribution throughout the fuel cell. By continuously circulating hydrogen from the outlet back to the inlet, the system ensures uniform hydrogen distribution and sustained optimal performance without requiring continuous excess hydrogen supply from external sources.
2Stability of the object's composition
If the fuel cell operates with excess hydrogen to ensure uniform partial pressure distribution, then performance homogeneity is improved, but hydrogen losses increase
Solution Approach 1:
The system recovers hydrogen from the anode outlet stream and recirculates it back to the inlet, preventing hydrogen loss. This recovery mechanism maintains the beneficial uniform partial pressure distribution while capturing and reusing the hydrogen that would otherwise be lost.
Solution Approach 2:
The recirculation system creates a feedback loop where hydrogen from the outlet is monitored and redirected back to the inlet. This feedback mechanism ensures that hydrogen distribution remains uniform throughout the cell by continuously adjusting the hydrogen flow based on outlet conditions, thereby maintaining stable composition without excessive hydrogen consumption.
3Object-generated harmful factors
If purge valves are opened to remove accumulated impurities (water, nitrogen, carbon dioxide) from the pressurized circuit, then impurity accumulation is reduced, but fuel losses increase (2-5% compared to ideal consumption)
Solution Approach 1:
The system extracts and separates impurities (water, nitrogen, carbon dioxide) from the hydrogen stream through the membrane electrode assembly. The membrane selectively allows hydrogen to pass through while retaining impurities, which are then removed from the recirculation loop, preventing impurity accumulation without requiring purge valve operations that would cause fuel loss.
Solution Approach 2:
The membrane electrode assembly acts as an intermediary that separates hydrogen from impurities. It facilitates the selective passage of hydrogen while blocking impurities, enabling impurity removal without the need for purge valves that would discharge valuable hydrogen fuel.
4Reliability
If purge devices using inert gas separation are used to prevent material degradation during shutdown, then material degradation is reduced, but device complexity and size increase
Solution Approach 1:
The membrane electrode assembly serves multiple functions: it generates electricity during operation, purifies hydrogen by removing impurities, and prepares inert gas for shutdown protection. This multi-functionality eliminates the need for separate dedicated purge devices, reducing overall system complexity and size while maintaining material degradation prevention capabilities.
Solution Approach 2:
The system generates its own inert gas for shutdown protection through the membrane separation process during normal operation. The inert gas is produced in-situ from the air feed, eliminating the need for external inert gas storage tanks or separate purge gas generation systems, thereby reducing device complexity and size.
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 device enhances fuel cell efficiency by recycling and purifying hydrogen, reducing hydrogen losses, and minimizing material degradation, while also compactly storing inert gases for effective purging, thus optimizing energy use and extending fuel cell lifespan.
Implementation Method 1
a membrane-electrode assembly (MEA) forming an electrochemical cell, the MEA being arranged, between the inlet E and the outlet A, so as to be traversed by a flow of hydrogen
Implementation Method 2
the anode of the MEA allows the dissociation, by oxidation, of the hydrogen into protons and electrons
Implementation Method 3
Only protons pass through the membrane to the cathode where they are recombined with electrons and oxygen to form water
Implementation Method 4
a hydrogen purification and compression unit
Data Source
AI summary
This device for supplying and recirculating hydrogen for a fuel cell, comprises: -a unit (1) for supplying hydrogen comprising a supply line L capable of being connected to the inlet of the anode compartment (6) of a fuel cell; -a unit (3) for purifying and compressing hydrogen, having an outlet A, and outlet B, and an inlet E capable of being connected at least to the outlet of the anode compartment (6) of a fuel cell, outlet A being suitable for being connected to the inlet of the anode compartment (6) of a fuel cell; -a gas storage tank (4), comprising an inlet connected to outlet B of the unit for purifying and compressing hydrogen, and an outlet connected to supply line L via a valve.