Regenerative Fuel Cell Water Tank for Hydrogen Removal
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Solution Overview
Problem
The water discharged from a fuel cell contains hydrogen, which, when supplied to the anode of a water electrolyzer, reacts with oxygen produced there, reducing the efficiency of oxygen production.
Innovation Solution
A regenerative fuel cell system with a water tank containing a recombiner that combines hydrogen and oxygen to produce water, maintaining lower internal pressure than the fuel cell and water electrolyzer, and using a temperature controller to stabilize the water tank's temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If water discharged from the fuel cell is supplied directly to the water electrolyzer, then the system structure is simple, but the oxygen production efficiency decreases due to hydrogen reaction with oxygen at the anode
Solution Approach 1:
A water tank is introduced as an intermediary component between the fuel cell and water electrolyzer. The water tank receives water discharged from the fuel cell, allowing hydrogen and oxygen to separate and recombine into water through a recombiner before the purified water is supplied to the water electrolyzer, thereby preventing hydrogen-oxygen reactions that would reduce oxygen production efficiency
Solution Approach 2:
Hydrogen and oxygen are extracted from the water discharged by the fuel cell through the water tank. The recombiner separates hydrogen and oxygen gases from the water and recombines them, removing hydrogen content from the water before it enters the water electrolyzer, thus eliminating the harmful reaction between hydrogen and oxygen
2Quantity of substance
If the water tank internal pressure is increased to match fuel cell pressure, then water flow is improved, but hydrogen and oxygen separation efficiency decreases
Solution Approach 1:
The internal pressure of the water tank is set to a parameter value lower than the fuel cell pressure (specifically, lower than 0.03 MPa). This parameter change optimizes the balance between water flow rate and hydrogen-oxygen separation efficiency, allowing sufficient water supply while maintaining effective gas separation and recombination in the recombiner
3Device complexity
If the water tank is exposed to external space on the lunar surface, then pressure control is simplified, but temperature stability deteriorates and water may freeze
Solution Approach 1:
A valve is introduced as a control intermediary between the water tank and external lunar space. The valve regulates the communication state between the water tank and external environment, allowing pressure control while preventing direct exposure that would cause temperature fluctuations and freezing
Solution Approach 2:
The valve controls the communication parameter between the water tank and external space, switching between open and closed states to maintain optimal pressure and temperature conditions for water storage and prevent freezing on the lunar surface
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
Reduces hydrogen content in the water supplied to the water electrolyzer, preventing efficiency loss and freezing, and allows for efficient oxygen production.
Implementation Method 1
a recombiner that is disposed in the water tank, and that combines hydrogen and oxygen to produce water
Implementation Method 2
a water electrolyzer that produces hydrogen and oxygen by electrolyzing water that is supplied from the water tank
Implementation Method 3
a fuel cell that generates power using hydrogen and oxygen
Data Source
AI summary
The regenerative fuel cell system includes a fuel cell, a water tank that stores water discharged from the fuel cell, a recombiner that is disposed in the water tank and generates water by combining hydrogen and oxygen, and a water electrolyzer that generates hydrogen and oxygen by electrolyzing the water supplied from the water tank. The internal pressure of the water tank storing the water is lower than the internal pressure of the fuel cell during power generation and the internal pressure of the water electrolyzer during electrolysis.