Thermally Integrated Solid Oxide Fuel Cell Stack Heat Management
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Solution Overview
Problem
Solid oxide fuel cell (SOFC) systems face inefficiencies due to excess heat not being effectively utilized, leading to lower fuel-to-electric efficiency and reduced durability of the SOFC stack, necessitating an improved thermal management system that integrates the fuel reformer with the SOFC stack.
Innovation Solution
A thermally integrated SOFC system is designed with a heat extractor and a fuel reformer-combustor module within a stack hotbox, where the heat extractor captures waste heat from the SOFC stack and directs it to the fuel reformer-combustor module, enhancing thermal efficiency and fuel utilization without increasing system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If excess heat is removed from the SOFC stack, then fuel-to-electric efficiency is improved and durability is enhanced, but system complexity increases due to additional thermal management components
Solution Approach 1:
The patent combines the waste heat removal function with the fuel reforming function by integrating the reformer within the stack hotbox and using the extracted heat directly for the endothermic reforming reaction. This merging eliminates the need for separate heat management systems while improving fuel-to-electric efficiency and enabling higher fuel utilization.
Solution Approach 2:
The patent converts the harmful excess heat that degrades stack durability into a beneficial resource by using it to drive the endothermic reforming reaction in the integrated reformer. This transforms waste heat into useful thermal energy for fuel conversion, simultaneously improving efficiency and reducing thermal stress on the stack.
2Reliability
If stack temperature is reduced to improve durability, then component lifespan is extended, but heat available for power generation is decreased
Solution Approach 1:
The patent segments the thermal management functions by extracting heat at a controlled rate through dedicated heat extraction pathways while maintaining the stack operating temperature for power generation. This allows simultaneous optimization of durability (through controlled heat removal) and power output (through maintained operating temperature).
Solution Approach 2:
The patent introduces the integrated reformer as an intermediary system that captures waste heat and uses it for the endothermic reforming reaction. This intermediary process removes excess heat that would otherwise degrade the stack, extending durability without compromising the stack's power generation temperature and capacity.
3Productivity
If fuel utilization is increased above 75 percent, then system efficiency is improved, but thermal management of the reformer becomes more difficult
Solution Approach 1:
The patent merges the reformer thermal management with the stack heat extraction system, using the same heat extraction infrastructure to provide thermal energy for the reforming reaction. This integrated approach simplifies thermal management while enabling higher fuel utilization by efficiently coupling the exothermic stack operation with the endothermic reforming process.
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
This integration increases the fuel-to-electric efficiency of the SOFC stack and overall system efficiency, improves durability by reducing stack temperature, and allows for higher fuel utilization, while maintaining system simplicity.
Implementation Method 1
a heat extractor disposed within the stack hotbox in thermal communication with the fuel cell stack
Implementation Method 2
the heat extractor captures waste heat from the SOFC stack
Implementation Method 3
a steam reformer (SR) wherein a hydrocarbon fuel, such as natural gas or methane or diesel, is contacted with steam and converted in an endothermic process into a synthesis gas (syngas)
Implementation Method 4
The anode tail gas can be recycled to a combustor and fully combusted to carbon dioxide and water with release of exothermic heat
Implementation Method 5
converted in an exothermic process into a synthesis gas composition
Implementation Method 6
a solid oxide electrolyte which transports oxide ions so produced from the cathode to a fuel electrode
Data Source
AI summary
This invention pertains to a thermally-integrated solid oxide fuel cell system, providing for a solid oxide fuel cell stack disposed within a stack hotbox; a heat extractor disposed within the stack hotbox in thermal communication with the fuel cell stack and circumscribed around a full or partial perimeter of the fuel cell stack; a fuel reformer-combustor module disposed within the stack hotbox in thermal communication with the stack and disposed around a full or partial perimeter of the heat extractor; and a manifold fluidly connecting an outlet of the heat extractor to an inlet of a reformer section of the fuel reformer-combustor module.