Fuel Cell Gas-Path Capture of Chromium and Sulfur Poisons
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Solution Overview
Problem
Current fuel cell systems are ineffective in capturing chromium (Cr) and sulfur (S) as poisonous substances, which can deteriorate electrode performance, particularly in solid oxide fuel cells, despite previous approaches using perovskite oxide and samarium-doped ceria.
Innovation Solution
Incorporating oxides with a corundum structure and titania-based oxides as capturing agents in the fuel gas and oxidizer gas supply passages to prevent electrode poisoning by forming a poisoning prevention layer on the inner surface of the interconnector, effectively adsorbing Cr and S before they reach the electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If perovskite oxide or samarium-doped ceria is used to remove poisonous elements, then electrode poisoning is reduced, but device complexity and material cost increase
Solution Approach 1:
The patent extracts and removes the poisonous elements (Cr and S) from the gas streams before they reach the electrodes using dedicated removing units. This separates the poisoning prevention function from the electrode structure itself, allowing the use of conventional, simpler electrode materials while maintaining performance.
Solution Approach 2:
The patent introduces intermediary components (poisonous element removing units with absorbents) that act as mediators between the gas supply system and the electrodes. These intermediaries capture Cr and S through adsorption, preventing direct contact with electrode catalysts while using conventional electrode materials.
2Ease of manufacture
If Cr-containing interconnectors are used to reduce cost, then manufacturing cost decreases, but electrode poisoning by Cr increases
Solution Approach 1:
The patent extracts Cr from the oxidizer gas stream using a poisonous element removing unit positioned between the air supply and the cathode. This allows the use of inexpensive Cr-containing interconnectors while preventing Cr vapor from reaching and poisoning the cathode catalyst.
Solution Approach 2:
The patent introduces an intermediary poisonous element removing unit that captures Cr vapor generated by Cr-containing interconnectors. This intermediary component protects the electrodes from Cr poisoning, enabling the use of cost-effective Cr-containing materials for interconnectors.
3Ease of manufacture
If sulfur-containing fuel is used to reduce cost, then fuel cost decreases, but electrode poisoning by S increases
Solution Approach 1:
The patent extracts sulfur (H2S) from the fuel gas stream using a poisonous element removing unit with an absorbent positioned between the fuel supply and the anode. This enables the use of inexpensive sulfur-containing fuels while preventing S from poisoning the anode catalyst.
Solution Approach 2:
The patent introduces an intermediary poisonous element removing unit that captures H2S from the fuel gas. This intermediary protects the anode from sulfur poisoning, allowing the use of low-cost sulfur-containing fuels.
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 solution effectively prevents electrode poisoning by Cr and S, maintaining fuel cell performance and allowing the use of inexpensive Fe-Cr alloys for interconnectors without risking electrode contamination.
Implementation Method 1
the oxide having the corundum structure and the titania-based oxide each has the function of capturing Cr and S
Data Source
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AI summary
A fuel cell system includes a fuel cell, a fuel gas supply passage supplying a fuel gas to an anode of the fuel cell, an oxidizer gas supply passage supplying an oxidizer gas to a cathode of the fuel cell, and a capturing component provided in an appropriate portion on the fuel gas supply passage and/or the oxidizer gas supply passage and containing a capturing agent to capture a poisonous substance. The poisonous substance is Cr and/or S. The capturing agent includes an oxide having a corundum structure and/or a titania-based oxide.