Solid Oxide Fuel Cell Anode Water Gas Shift Catalyst Integration
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Solution Overview
Problem
Intermediate-temperature solid oxide fuel cells face challenges in efficiently utilizing carbon monoxide as fuel due to the need for external water supply and risk of carbon deposition, especially at lower temperatures, and existing reforming methods are energy-intensive and complex.
Innovation Solution
A method involving a fuel rich in carbon monoxide that contacts a water gas shift reaction catalyst within the fuel cell, eliminating the need for external water and optimizing the steam-to-carbon ratio to facilitate internal water gas shift reactions, combined with a CPOX reformer and strategically placed WGS catalyst for efficient energy extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If external water supply is used for water gas shift reaction, then carbon monoxide conversion is improved, but system complexity and cost increase
Solution Approach 1:
The fuel cell system utilizes its own internally produced steam from the electrochemical oxidation of hydrogen to drive the water gas shift reaction. The steam generated at the anode during hydrogen oxidation automatically provides the necessary water for CO conversion, eliminating the need for external water supply systems, pumps, and control mechanisms.
Solution Approach 2:
The invention combines the water gas shift reaction catalyst directly within the fuel cell anode structure, merging two previously separate functions (reforming and fuel cell operation) into a single integrated component. This integration eliminates the need for separate external water supply infrastructure while enabling efficient CO conversion.
2Productivity
If external water supply is used for water gas shift reaction, then carbon monoxide conversion is improved, but cost increases
Solution Approach 1:
The system generates its own water requirement internally through the electrochemical oxidation of hydrogen at the anode, which produces steam. This self-sufficient approach eliminates the need for external water supply infrastructure, pumps, controls, and associated costs, making the system more economically viable.
3Device complexity
If internal reforming is implemented, then system complexity is reduced, but carbon deposition risk increases at lower temperatures
Solution Approach 1:
The invention optimizes the steam-to-carbon ratio parameter within the fuel cell anode to maintain conditions that prevent carbon deposition. By carefully controlling the amount of steam present from internal hydrogen oxidation and the residence time of the reformate gas, the system achieves effective CO conversion without the carbon deposition problems that plague lower-temperature internal reforming systems.
Solution Approach 2:
The water gas shift reaction catalyst acts as an intermediary that facilitates CO conversion through a different mechanism than direct electrochemical oxidation. This catalytic pathway allows CO conversion to proceed efficiently without requiring the high temperatures that would otherwise be needed to prevent carbon deposition during internal reforming.
4Device complexity
If full internal reforming is implemented, then system complexity is reduced, but energy consumption increases
Solution Approach 1:
Rather than implementing full internal reforming of all fuel components, the system performs partial reforming and relies on the water gas shift reaction to handle the majority of CO conversion. This partial approach to internal reforming, combined with the WGS catalyst, achieves effective CO utilization without the excessive energy consumption that would result from complete internal reforming at high temperatures.
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 enables high efficiency, reduced system complexity, and lower costs by utilizing residual water within the fuel, effectively converting carbon monoxide without external water supply, and minimizing carbon deposition, while maintaining quick response times and thermal coupling for effective fuel cell operation.
Implementation Method 1
the carbon monoxide of the synthesis gas can either, through a reaction with steam be converted to carbon dioxide with hydrogen in the water gas shift reaction (WGS)
Implementation Method 2
convert a hydrocarbon fuel such as propane to a synthesis gas containing hydrogen, carbon monoxide and nitrogen by oxidising the hydrocarbon with a sub-stoichiometric amount of air - such as by the use of a catalytic partial oxidation (CPOX) reformer
Implementation Method 3
the resulting synthesis gas may be used as a fuel for a solid-oxide fuel cell
Data Source
Figure 1a~1b
Figure 2~4
AI summary
A method of fuelling an intermediate-temperature solid oxide fuel cell comprising the steps of providing (11b) a fuel rich in carbon monoxide to the anode region (10d) of the fuel cell, after the fuel has contacted a water gas shift reaction catalyst (10bl, 10b2) in the region of the anode, so that the water gas shift reaction occrus due to the presence of residual water in the fuel, and/or steam produced at the anode, and also a fuel cell assembly incorporating the method comprising an anode (10d), a cathode 10f separated from said anode, a gas impermeable electrolyte (10e) between said anode and said cathode, first means for the supply of oxidant to the cathode lie, second means lib for the supply of fuel to the anode, wherein said second means comprises a water gas shift reaction catalyst (10bl, 10b2) disposed closed to the anode to catalyse the water gas shift reaction between carbon monoxide in said fuel and water/steam occurring as a residual in said fuel or from the reaction at the anode. There is also a method of applying a catalyst to a metal substrate by ink- jet printing