Fuel Cell Combustor Control for Anode Oxidation Prevention
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Solution Overview
Problem
Fuel cell systems face challenges in preventing oxidative degradation of the anode pole during stop processes, as existing methods like applying reverse-bias voltage are not entirely effective.
Innovation Solution
A fuel cell system that includes a combustor to combust fuel and oxidizing gas, supplying combustion gas to the cathode inlet, and a controller to manage fuel and oxidizing gas supply, employing a post-stop-request combustor-supply control unit to maintain a specific excess air ratio and adjust fuel and oxidizing gas supply to reduce anode pole oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reverse-bias voltage is applied to prevent oxidative degradation of the anode pole, then the anode pole protection is improved, but the system complexity and energy consumption increase
Solution Approach 1:
The patent extracts the essential function of preventing anode oxidation by removing oxygen from the anode environment, rather than applying electrical voltage. This is achieved by controlling the combustor to create an oxygen-depleted atmosphere that naturally protects the anode without requiring reverse-bias voltage application infrastructure
Solution Approach 2:
The patent introduces combustion gas as an intermediary substance that mediates between the cathode and anode environments. By controlling the combustor to produce oxygen-depleted combustion gas, it creates a protective barrier that prevents oxygen from reaching the anode, thereby protecting it from oxidation without direct electrical intervention
2Reliability
If fuel and oxidizing gas are supplied to combustor after stop request, then anode pole oxidation is reduced, but energy consumption increases
Solution Approach 1:
The patent applies partial action by supplying fuel and oxidizing gas to the combustor at reduced levels after stop request, rather than maintaining full operation. This provides just enough combustion to maintain oxygen depletion in the anode environment without excessive energy consumption, achieving minimal effective protection
Solution Approach 2:
The patent implements periodic action by controlling the combustor operation in cycles - maintaining fuel and oxidizing gas supply during periods when anode protection is needed, and reducing or stopping supply when protection is less critical. This periodic control optimizes energy usage while maintaining reliability
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
Effectively reduces oxidative degradation of the anode pole by controlling the oxygen partial pressure and maintaining a stable environment during system stop processes, extending the fuel cell's durability and performance.
Implementation Method 1
a combustor configured to combust a fuel and an oxidizing gas to supply a combustion gas to a cathode inlet of the fuel cell
Implementation Method 2
a fuel cell configured to be provided with a fuel gas and an oxidizing gas to generate electric power
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A fuel cell system comprising: a fuel cell; a combustor configured to combust a fuel and an oxidizing gas to supply a combustion gas to a cathode inlet of the fuel cell; a combustion fuel supply device configured to supply a fuel to the combustor; a combustion oxidizing gas supply device configured to supply an oxidizing gas to the combustor; an anode-discharged-gas discharge passage configured to discharge an anode discharged gas from an anode outlet of the fuel cell; a cathode-discharged-gas discharge passage configured to discharge a cathode discharged gas from a cathode outlet of the fuel cell; and a controller configured to control a supply of the fuel to the combustor by the combustion fuel supply device and a supply of the oxidizing gas to the combustor by the combustion oxidizing gas supply device, wherein the controller includes a post-stop-request combustor-supply control unit configured to execute the supply of the fuel and the supply of the oxidizing gas to the combustor after a request for stopping the fuel cell system.