SOFC Reformer Heating With Steam to Protect Nickel Catalysts
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Solution Overview
Problem
Nickel-based catalysts in SOFC systems face challenges during heating-up operations, where nickel can oxidize, leading to reduced efficiency and potential damage to the catalyst structure.
Innovation Solution
A method involving the use of a carbon-containing fluid and steam through a nickel-based catalyst in the reformer, with oxygen provided in chemically bound form within the steam, to maintain nickel in a reduced state and prevent oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If oxygen-containing gas is added to carbon-containing gas during heating-up operation, then carbon deposits are avoided through oxidation, but nickel catalyst oxidizes and requires additional protective measures
Solution Approach 1:
Steam is introduced as an intermediary substance that provides oxygen in a controlled, chemically bound form. The steam reacts with carbon-containing gas to provide oxygen for carbon oxidation while the hydrogen component protects nickel from oxidation, acting as a mediator that balances both requirements
Solution Approach 2:
The chemical composition and oxidation state of the gas phase are changed by introducing steam. This alters the oxygen availability and redox environment, enabling carbon oxidation while maintaining nickel in a reduced state through controlled parameter modification of the heating atmosphere
2Reliability
If purge gas or protective gas is used during heating-up operation, then nickel oxidation is prevented, but carbon deposits may form due to lack of oxygen for carbon oxidation
Solution Approach 1:
Different chemical environments are created in different zones: the steam provides oxygen near carbon-containing surfaces for oxidation, while the hydrogen-rich environment near nickel catalyst maintains reducing conditions, applying local quality variations to address different requirements in different locations
Solution Approach 2:
Steam serves multiple functions simultaneously: it provides oxygen for carbon oxidation, maintains a reducing environment for nickel protection through hydrogen, and controls the overall atmosphere composition, making it a multi-functional medium that addresses both problems
3Reliability
If additional measures are taken to keep nickel reduced during heating-up operation, then nickel oxidation is prevented, but system complexity increases
Solution Approach 1:
The complex multi-gas control system is replaced by extracting and using only steam as the key protective medium. This simplifies the heating-up procedure by removing the need for separate purge gas and oxygen-containing gas management, while still achieving nickel protection and carbon oxidation
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 approach effectively keeps nickel reduced during the heating process, preventing oxidation and maintaining catalyst efficiency, while also avoiding carbon deposits through a controlled steam-to-carbon ratio.
Implementation Method 1
Oxygen is fed to the nickel-based catalyst during the heating process through the steam. However, in contrast to the methods known in the prior art, the oxygen in the steam is provided in chemically bound form.
Implementation Method 2
the remaining hydrogen ensures that nickel remains reduced and does not oxidise
Implementation Method 3
starting a heating process for heating the fuel cell system with a heating device
Implementation Method 4
a reformer upstream of the anode portion for steam reforming using a fuel, the reformer comprising a nickel-based catalyst
Data Source
AI summary
The present invention relates to a method for heating a fuel cell system (1a; 1b; 1c; 1d) comprising at least one fuel cell stack (2) with an anode portion (3) and a cathode portion (4), and a reformer (5) upstream of the anode portion (3) for steam reforming using a fuel, the reformer (5) comprising a nickel-based catalyst, said method having the following steps: starting a heating process for heating the fuel cell system (1a; 1b; 1c; 1d) with a heating device (6) and conducting a carbon-containing fluid and conducting steam through the nickel-based catalyst of the reformer (5) during the heating process. The invention also relates to a fuel cell system (1a; 1b; 1c; 1d) which is designed to carry out a method according to the invention.