Fuel Cell Exhaust Condensation and Pressure-Controlled Hydrogen Recycle
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Solution Overview
Problem
Fuel cell systems, particularly solid oxide fuel cell systems, face inefficiencies in hydrogen utilization and water management, leading to suboptimal performance and increased costs due to the need for complex mass flow control systems and limited fuel recycling capabilities.
Innovation Solution
A hydrogen power fuel cell system incorporating a condenser for water removal from fuel exhaust and a recycle blower for pressurizing recycled fuel, which simplifies the system by eliminating the need for mass flow controllers and enhancing fuel utilization efficiency through pressure control and recycling of dewatered hydrogen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mass flow controllers are used to control hydrogen flow in fuel cell systems, then fuel utilization efficiency can be improved, but system complexity and cost increase
Solution Approach 1:
The patent removes mass flow controllers from the system by extracting this control function entirely. Instead of using active mass flow control devices, the system relies on passive pressure control mechanisms and the natural characteristics of the fuel cell stack to achieve desired fuel utilization efficiency, thereby reducing system complexity while maintaining productivity
Solution Approach 2:
The fuel cell stack itself is utilized to provide flow control characteristics through its inherent pressure-drop characteristics and operating conditions. The system leverages the stack's own properties to regulate fuel flow without requiring external mass flow controllers, enabling the system to self-regulate fuel utilization
2Loss of substance
If water is removed from fuel exhaust using conventional methods, then fuel recycling quality improves, but system complexity and cost increase
Solution Approach 1:
The patent employs condensation (phase transition from vapor to liquid) to remove water from the fuel exhaust stream. By cooling the exhaust below the dew point, water vapor condenses into liquid form and can be easily separated from the hydrogen gas, achieving effective water removal and high-quality fuel recycling without complex separation systems
Solution Approach 2:
The system controls the temperature parameter of the fuel exhaust to enable water condensation. By adjusting the exhaust temperature below the dew point through simple cooling mechanisms, water is removed from the recycled fuel stream, improving recycling quality while avoiding complex water separation 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
The system achieves nearly 100% hydrogen fuel utilization and increased efficiency by recycling and pressurizing dewatered hydrogen, reducing system complexity and costs while maintaining high performance.
Implementation Method 1
a condenser configured to remove water from the fuel exhaust to generate recycled fuel
Implementation Method 2
a recycle blower configured to pressurize the recycled fuel output from the condenser
Implementation Method 3
Fuel cells, such as solid oxide fuel cells, are electrochemical devices which can convert energy stored in fuels to electrical energy with high efficiencies
Data Source
AI summary
A method of operating a fuel cell power system includes providing a fresh hydrogen fuel to power modules that each contain a heater and a stack of fuel cells, providing a fuel exhaust containing hydrogen and water from the stack to a condenser, removing water from the fuel exhaust to generate a recycled fuel containing dewatered hydrogen, and pressurizing and recycling the recycled fuel output from the condenser to the power modules. The removed water may be vaporized in a stack cathode exhaust.