Hydrogen Circulation System Using Ejector for Fuel Cell
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Solution Overview
Problem
In fuel cell systems operating in dead-end mode, hydrogen consumption is high due to inefficient recycling, leading to reduced fuel efficiency and increased costs, as existing recycling methods consume power and are expensive.
Innovation Solution
A hydrogen circulation system incorporating a hydrogen supply pipeline, return pipeline, buffer tank, ejector, differential pressure valve, solenoid valve, and controller, which recycles hydrogen by using an ejector to mix returned hydrogen with fresh hydrogen, adjusts pressure differences, and controls impurity purging to prevent membrane damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If hydrogen circulation pump is used to recycle hydrogen, then hydrogen consumption is reduced, but system cost and power consumption increase
Solution Approach 1:
The patent extracts the hydrogen circulation function from the traditional pump-based system and implements it through the natural pressure differential and flow characteristics of the fuel cell stack itself. The ejector device utilizes the high-velocity hydrogen flow from the anode outlet to create a suction effect that draws unreacted hydrogen back into the circulation loop, eliminating the need for an active pump and reducing system complexity and cost.
Solution Approach 2:
The fuel cell stack's own operating characteristics (pressure differential, gas flow) are harnessed to drive the hydrogen circulation process. The system uses its own internal energy and flow dynamics to recycle hydrogen without requiring external power input for circulation, making the process self-sustaining and reducing overall system complexity.
2Loss of substance
If hydrogen circulation pump is used to recycle hydrogen, then hydrogen consumption is reduced, but power consumption increases
Solution Approach 1:
The circulation system leverages the natural pressure differential and high-velocity gas flow already present in the fuel cell operation to drive hydrogen recycling. The ejector converts the kinetic energy of the outgoing hydrogen stream into a suction effect that pulls unreacted hydrogen back into the system, requiring no additional power input and reducing overall energy consumption.
Solution Approach 2:
The patent replaces the mechanical pump system (which requires electrical power) with a passive ejector-based circulation mechanism that utilizes fluid dynamics and pressure differentials. This substitution eliminates the need for motor-driven circulation equipment, thereby reducing power consumption while maintaining effective hydrogen recycling.
3Reliability
If purge is performed to discharge impurities, then power generation performance is maintained, but hydrogen consumption increases
Solution Approach 1:
The ejector-based circulation system continuously recycles unreacted hydrogen back into the anode inlet, maintaining a continuous loop of useful hydrogen utilization. This continuous circulation minimizes the frequency and intensity of purge operations needed to remove impurities, thereby reducing hydrogen loss while maintaining power generation performance.
Solution Approach 2:
Instead of discarding unreacted hydrogen during purge operations, the system recovers it through continuous circulation. The ejector captures hydrogen that would otherwise be wasted and returns it to the reaction zone, maximizing hydrogen utilization and reducing consumption while still allowing periodic impurity removal when necessary.
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 system reduces hydrogen consumption, enhances fuel cell efficiency, and lowers operational costs by effectively recycling hydrogen and managing pressure differences to protect the membrane electrode assembly, while maintaining power generation efficiency.
Implementation Method 1
The ejector is installed at the hydrogen supply pipeline and connects to the buffer tank and is configured to transmit the returned hydrogen in the buffer tank to the hydrogen supply pipeline
Implementation Method 2
The differential pressure valve is installed at the hydrogen supply pipeline between the hydrogen source and the ejector and is configured to adjust a pressure in the hydrogen supply pipeline based on a pressure difference between the anode inlet and a cathode inlet of the fuel cell stack
Data Source
AI summary
A hydrogen circulation system for fuel cell includes a hydrogen supply pipeline, a return pipeline, a buffer tank, an ejector, a differential pressure valve, a solenoid valve, and a controller. The return pipeline connects a hydrogen outlet of a fuel cell stack and the hydrogen supply pipeline. The buffer tank is installed at the return pipeline. The ejector is installed at the hydrogen supply pipeline for connecting the buffer tank. The differential pressure valve is between a hydrogen source and the ejector for adjusting a pressure in the hydrogen supply pipeline based on a pressure difference between an anode inlet and a cathode inlet of the fuel cell stack. The solenoid valve is installed at the return pipeline between the buffer tank and the hydrogen outlet. According to an output voltage or a load of the fuel cell stack, a switch of the solenoid valve is controlled by the controller.