High-Temperature Fuel Cell System Thermal Management
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Solution Overview
Problem
High-temperature fuel cell systems for mobile use face challenges with frequent start cycles, leading to prolonged heating times and reduced efficiency due to high thermal losses and sensitivity to thermo-cycles, while existing solutions lack effective thermal integration and waste heat utilization.
Innovation Solution
A system with a reformer connected upstream of the high-temperature fuel cells, a start burner for preheating cathodes, and an afterburner for complete oxidation of unconverted fuel components, coupled with an operating heat exchanger for preheating the oxidizing agent, and a desulfurization device to manage sulfur-containing elements, employing a dry reforming process and catalytic partial oxidation to enhance efficiency and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-temperature fuel cells are used for mobile applications, then electrical energy can be generated, but heating time increases and efficiency decreases due to frequent start cycles
Solution Approach 1:
A start burner is integrated into the system to preheat the fuel cell stack before main operation begins. This preliminary heating action reduces the time required to reach operating temperature during frequent start cycles, directly addressing the heating time loss issue while maintaining the electrical energy generation capability
2Power
If high-temperature fuel cells are used, then electrical energy can be generated, but thermal losses increase due to poor surface-to-volume ratio
Solution Approach 1:
The system merges the start burner, afterburner, and heat exchanger into an integrated thermal management system. The afterburner captures exhaust heat and the heat exchanger transfers it back to preheat incoming air and fuel, creating a combined heat and power system that recovers thermal losses and improves overall efficiency
3Adaptability or versatility
If frequent start cycles are necessary, then mobile use is enabled, but safety risks increase due to repeated thermal stress
Solution Approach 1:
The system incorporates gradual heating protocols through the start burner and thermal management system that cushion the thermal stress during frequent start cycles. This progressive heating approach prevents sudden thermal shocks to the fuel cell stack, maintaining reliability and safety while enabling mobile use with frequent start-stop operations
4Productivity
If waste heat is utilized, then efficiency improves, but system complexity increases
Solution Approach 1:
The afterburner and heat exchanger are designed to serve multiple functions: they recover waste heat for preheating, manage thermal stress during start cycles, and control exhaust emissions. This multi-functionality improves system efficiency through waste heat utilization while minimizing the increase in overall system complexity by combining functions into integrated components
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 a significant reduction in heating time, improved efficiency, and enhanced safety by utilizing waste heat for preheating and efficient thermal management, allowing for minimal heating energy consumption and reduced system complexity.
Implementation Method 1
a dry reforming process should be used for the reforming of the starting fuel to a fuel which is rich in hydrogen and which substantially comprises CO and H2
Implementation Method 2
A catalytic partial oxidization with air (CPOx) can therefore be used
Implementation Method 3
a start burner is present for the preheating of the cathodes of the high-temperature fuel cells
Implementation Method 4
with an afterburner, components of the fuel and of the oxidizing agent which are not converted in the electrochemical reaction can be oxidized at least approximately completely
Implementation Method 5
The oxidizing agent is in this respect preheated with the exhaust gas of the high-temperature fuel cells during the operation of the system
Implementation Method 6
The fuel leaving the reformer after the reforming can be supplied to the anodes of the fuel cells and can be electrochemically converted using an oxidizing agent
Implementation Method 7
any elements containing sulfur which are present should be catalytically absorbed in a desulfurization device prior to the fuel preparation in the system
Data Source
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AI summary
The invention relates to a system having high- temperature fuel cells, for example SOFCs. It is in particular provided for mobile use. The invention relates to a system having high-temperature fuel cells, for example SOFCs. It is the object of the invention to provide such a system which is suitable for mobile use with frequent start cycles and, in this respect, a shortened heating time and, in this respect, sufficient safety is given during operation. A reformer connected upstream of the high-temperature fuel cells at the anode side, a start burner for the preheating of the cathodes of the high-temperature fuel cells, an afterburner and an operating heat exchanger are present at the system in accordance with the invention. Oxidizing agent can be supplied to the high-temperature fuel cell cathodes through the operating heat exchanger. In addition, it can be heated with the exhaust gas of the high-temperature fuel cells. Exhaust gas conducted through the operating heat exchanger can flow in an exhaust gas line together with environmental air and can then be conducted away into the environment as cooled exhaust gas.