Solid-oxide fuel cell shutdown gas compensation
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Solution Overview
Problem
Conventional solid-oxide fuel cell systems face durability issues due to repeated temperature changes causing gas contraction, which leads to air infiltration, anode oxidation, and subsequent electrolyte stress, peeling, and catalyst agglomeration, resulting in performance deterioration.
Innovation Solution
A solid-oxide fuel cell system configuration where the electric power generation raw material supplier and oxidizing gas supplier are controlled to compensate for gas contraction in the combustible gas channel and maintain adequate oxidizing gas flow in the cathode channel after power generation stops, reducing air infiltration and oxidation-related deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the solid-oxide fuel cell system is stopped and temperature decreases, then power generation is halted, but gas contraction occurs causing air infiltration and anode oxidation
Solution Approach 1:
The system applies preliminary anti-action by supplying raw material gas to the combustible gas channel before air infiltration can occur. This preventive measure counteracts the harmful effect of air entering the anode gas channel by maintaining positive pressure with fuel gas, thereby preventing anode oxidation during the stopping phase
Solution Approach 2:
The controller is configured to supply raw material gas to the combustible gas channel before the temperature decrease causes significant gas contraction. This preliminary action ensures that the anode remains protected from air infiltration during the cooling process, maintaining system durability
2Reliability
If raw material gas is supplied to the combustible gas channel, then gas contraction is compensated and air infiltration is prevented, but system complexity increases
Solution Approach 1:
The existing raw material gas supplier is made multi-functional by utilizing it for both normal power generation operation and for protecting the anode during stopping phase. This eliminates the need for a separate protection system, thereby avoiding increased device complexity while maintaining durability
Solution Approach 2:
The system uses its own raw material gas supply infrastructure to protect itself during shutdown. The controller orchestrates the use of existing components (raw material gas supplier and combustor) to perform the protective function, avoiding additional dedicated components and keeping the control system relatively simple
3Object-generated harmful factors
If the combustor is used to burn off gas, then combustion treatment is achieved, but additional energy consumption occurs
Solution Approach 1:
The system converts the harmful combustible gas that would otherwise be wasted into a beneficial resource by using it as fuel in the combustor. The combustible gas from the anode off-gas is burned to generate heat, which maintains the fuel cell stack temperature during shutdown, thereby converting a harmful discharge into a useful heating source
Solution Approach 2:
The stopping process merges two functions: the combustor simultaneously performs combustion treatment of off-gas and heat generation for maintaining stack temperature. This combined approach eliminates the need for separate heating systems, reducing energy consumption while achieving both harmful factor removal and thermal maintenance
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 configuration enhances the durability of the solid-oxide fuel cell system by timely compensating for gas contraction and minimizing reduction deterioration, thereby extending the system's operational lifespan.
Implementation Method 1
a gas in a reformer contracts due to a temperature decrease of the reformer
Implementation Method 2
an oxidizing gas is supplied to the cathode gas channel in accordance with the supply of the electric power generation raw material
Implementation Method 3
a solid-oxide fuel cell system includes a fuel cell unit, an electric power generation raw material supplier that supplies an electric power generation raw material to the fuel cell unit, and an oxidizing gas supplier that supplies an oxidizing gas to the fuel cell unit
Implementation Method 4
an off gas that is a mixture of a fuel gas and an oxidizing gas which have not been used in a solid-oxide fuel cell is subjected to a combustion treatment
Data Source
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AI summary
A solid-oxide fuel cell system includes: a fuel cell unit including a solid-oxide fuel cell including an anode gas channel and a cathode gas channel and a mixer configured to mix an anode off gas discharged from the anode gas channel and a cathode off gas discharged from the cathode gas channel; an electric power generation raw material supplier configured to supply an electric power generation raw material to the fuel cell unit; a combustible gas channel extending from the electric power generation raw material supplier to a downstream end of the anode gas channel; an oxidizing gas supplier configured to supply an oxidizing gas to the cathode gas channel; and a controller configured to, after electric power generation of the fuel cell unit is stopped, control the electric power generation raw material supplier to supply to the combustible gas channel the electric power generation raw material, the amount of which compensates for contraction of a gas in the combustible gas channel due to temperature decrease of the fuel cell unit and also control the oxidizing gas supplier to supply the oxidizing gas to the cathode gas channel in accordance with the supply of the electric power generation raw material.