Fuel Cell Module Start-Up Combustor and Channel Switching
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Solution Overview
Problem
In fuel cell systems, prolonged heating by the exhaust gas combustor can lead to excessive heating of peripheral components, potentially causing damage.
Innovation Solution
A fuel cell module design that includes a start-up combustor, air preheater, and channel switching unit to control the heating process, allowing for efficient heating without prolonged use of the exhaust gas combustor, and ensuring that only the necessary gases are supplied to the fuel cell stack at high temperatures to prevent oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the exhaust gas combustor is used for heating the fuel cell stack, then the heating process can be performed, but peripheral components may be heated excessively and damaged
Solution Approach 1:
The heating system is segmented into two independent combustors: a start-up combustor for initial heating and an exhaust gas combustor for sustained operation. This segmentation allows the start-up combustor to perform the heating function without involving the exhaust gas combustor, thereby preventing excessive heating of peripheral components while still achieving the required heating temperature.
Solution Approach 2:
The start-up combustor acts as an intermediary device that performs the heating function during the critical start-up phase. By introducing this intermediary heating source, the system can achieve the necessary heating temperature without using the exhaust gas combustor, thus avoiding the harmful effect of excessive heating on peripheral components.
2Temperature
If the exhaust gas combustor is used for heating, then heating can be achieved, but the heating period becomes long causing damage to peripheral components
Solution Approach 1:
The heating process is segmented into two phases: initial heating by the start-up combustor and sustained operation by the exhaust gas combustor. This segmentation enables the system to complete the heating process more efficiently by using the start-up combustor for rapid initial heating, thereby reducing the overall heating period and preventing damage from prolonged operation.
Solution Approach 2:
The start-up combustor performs preliminary heating action before the exhaust gas combustor is activated. This preliminary action allows the fuel cell stack to reach the necessary operating temperature quickly, reducing the duration that the exhaust gas combustor needs to operate and thereby preventing damage to peripheral components from prolonged heating.
3Quantity of substance
If fuel is supplied to the evaporator and reformer, then fuel gas can be produced, but the system complexity increases with multiple channels and switching units
Solution Approach 1:
The fuel supply system is designed with multi-functionality where the first and second fuel supply channels can serve different purposes: the first channel supplies fuel to the start-up combustor for heating, while the second channel supplies fuel to the evaporator and reformer for fuel gas production. This universal design allows the system to perform multiple functions using a unified channel switching structure, managing complexity while maintaining versatility.
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 design effectively suppresses excessive heating of peripheral components and ensures efficient heating processes, preventing damage while maintaining optimal fuel cell operation by selectively routing fuel and oxygen-containing gases through the system.
Implementation Method 1
The reformer reforms raw fuel chiefly containing hydrocarbon to thereby produce the fuel gas supplied to the fuel cell stack
Implementation Method 2
The evaporator evaporates water, and supplies water vapor to the reformer
Implementation Method 3
The exhaust gas combustor combusts the fuel gas discharged from the fuel cell stack as a fuel exhaust gas and the oxygen-containing gas discharged from the fuel cell stack as an oxygen-containing exhaust gas to thereby produce a combustion exhaust gas
Implementation Method 4
The start-up combustor combusts the raw fuel and the oxygen-containing gas to thereby produce a combustion gas
Implementation Method 5
The air preheater heats the oxygen-containing gas by heat exchange with one of the combustion gas and the combustion exhaust gas, and supplies the heated oxygen-containing gas to the fuel cell stack
Implementation Method 6
a fuel cell stack formed by stacking a plurality of fuel cells for generating electrical energy by electrochemical reactions of a fuel gas and an oxygen-containing gas
Data Source
AI summary
A fuel cell unit of a fuel cell module includes a fuel cell stack, a reformer, an evaporator, an exhaust gas combustor, a start-up combustor, and an air preheater. The fuel cell module further includes an air supply channel, a first fuel supply channel, a second fuel supply channel, a switching valve, and an exhaust gas channel. In the exhaust gas channel, the start-up combustor and the air preheater are arranged in the order recited toward the downstream side in a flow direction of a combustion exhaust gas.