Fuel Cell Separation Membrane Permeability Optimization
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Solution Overview
Problem
Existing fuel cell systems face efficiency losses due to hydrogen permeation through separation membranes used to remove carbon dioxide and water vapor from anode exhaust gases, which reduces the fuel utilization rate and overall power generation efficiency.
Innovation Solution
A fuel cell system design that optimizes the permeability coefficient ratio of the separation membrane for carbon dioxide and water vapor to hydrogen, allowing for enhanced recycling of these gases without the need for additional sweep gases or pressure reduction systems, thereby increasing the fuel utilization rate and power generation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a separation membrane is used to remove carbon dioxide and water vapor from anode exhaust gas, then the concentration of hydrogen and carbon monoxide is increased and power generation efficiency is improved, but hydrogen permeates through the membrane which reduces fuel utilization rate
Solution Approach 1:
The invention changes the permeability parameters of the separation membrane by optimizing its composition and structure. The membrane is designed with specific permeability coefficients where carbon dioxide permeability (PCO2) is 30 times or more that of hydrogen (PH2), and water vapor permeability (PH2O) is 6 times or more that of hydrogen. This parameter optimization allows selective removal of carbon dioxide and water vapor while minimizing hydrogen loss, resolving the contradiction between improving power generation efficiency and maintaining fuel utilization rate.
2Productivity
If conventional separation membranes are used to remove carbon dioxide and water vapor, then gas concentration is improved, but additional sweep gases or pressure reduction systems are required which increases system complexity
Solution Approach 1:
The invention enables the separation membrane to perform its function autonomously without requiring external sweep gases or pressure reduction systems. The membrane's optimized permeability characteristics allow carbon dioxide and water vapor to pass through naturally driven by their concentration gradients, while hydrogen is retained. This self-service mechanism eliminates the need for additional complex equipment, resolving the contradiction between improving fuel utilization and reducing system complexity.
3Object-generated harmful factors
If hydrogen permeation through the membrane is allowed, then carbon dioxide and water vapor removal is achieved, but the amount of reusable fuel is reduced
Solution Approach 1:
The invention optimizes the permeability parameters of the separation membrane to achieve selective gas transport. By designing the membrane with specific permeability coefficients (PCO2/PH2 ≥ 30 and PH2O/PH2 ≥ 6), carbon dioxide and water vapor are removed effectively while hydrogen permeation is minimized. This parameter control resolves the contradiction between removing harmful gases and preserving reusable fuel quantity.
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 optimized permeability ratio enhances the power generation efficiency by promoting the recycling of carbon dioxide and water vapor, reducing production costs, and simplifying the system while maintaining membrane durability and reliability.
Implementation Method 1
a separation membrane separating at least one of carbon dioxide or water vapor from an anode off gas discharged from the first fuel cell
Data Source
AI summary
A fuel cell system including: a first fuel cell performing power generation using a fuel gas; a separation membrane separating at least one of carbon dioxide or water vapor from an anode off gas discharged from the first fuel cell; a second fuel cell disposed in the downstream of the separation membrane and performing power generation using the anode off gas, the anode off gas having at least one of carbon dioxide or water vapor separated therefrom; and a distribution channel disposed on a permeation side of the separation membrane and distributing any of the following: a raw material gas serving as the fuel gas to be reformed and used for the power generation of the first fuel cell, a cathode gas including oxygen to be used for the power generation of the first fuel cell, an anode off gas discharged from the second fuel cell, a cathode off gas discharged from the first fuel cell and to be supplied to the second fuel cell, or a cathode off gas discharged from the second fuel cell, in which at least one of permeability coefficient ratio α1 of the separation membrane or permeability coefficient ratio α2 of the separation membrane is 30 or higher.