SOFC Fuel Processing for Peak Shaving Gas Without Coking
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Solution Overview
Problem
Conventional solid oxide fuel cell (SOFC) systems face issues with coking and catalyst deactivation when using peak shaving gases containing air and higher hydrocarbons, leading to reduced efficiency and shorter fuel cell stack life.
Innovation Solution
A fuel cell system comprising a catalytic partial oxidation reactor, air injection, oxidation catalyst to reduce O2 content, hydrogenation catalyst to saturate unsaturated hydrocarbons, and a reforming catalyst to generate reformed fuel for the fuel cell stack, allowing operation with a wide range of peak shaving gas compositions without coking or catalyst deactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If peak shaving gas containing air and higher hydrocarbons is used to maintain system operation during peak demand, then fuel flexibility and adaptability are improved, but coking and catalyst deactivation occur leading to reduced reliability
Solution Approach 1:
The fuel processing function is divided into multiple sequential catalytic stages: oxidation catalyst for O2 removal, hydrogenation catalyst for unsaturated hydrocarbon saturation, and reforming catalyst for hydrocarbon conversion. Each segment addresses specific harmful components, preventing coking and catalyst deactivation while maintaining fuel flexibility
Solution Approach 2:
Catalysts serve as intermediary substances that facilitate controlled chemical reactions between fuel components and reactants. The oxidation catalyst mediates O2 removal, hydrogenation catalyst mediates saturation reactions, and reforming catalyst mediates hydrocarbon conversion, preventing direct harmful interactions that cause coking
2Power
If higher hydrocarbon content fuel is used to meet peak energy demand, then energy output is improved, but coking increases leading to shorter fuel cell stack life
Solution Approach 1:
The oxidation catalyst performs preliminary removal of O2 from the fuel stream before the fuel reaches the reforming catalyst. This preliminary action prevents O2 from causing unwanted oxidation and coking reactions in downstream components, enabling safe use of higher hydrocarbon content fuels
Solution Approach 2:
The hydrogenation catalyst converts unsaturated hydrocarbons (which cause coking) into saturated hydrocarbons by adding hydrogen. This transforms a harmful substance into a beneficial one that can be safely reformed into fuel cell feedstock, maintaining energy output while extending stack life
3Stability of the object's composition
If air is added to peak shaving gas to maintain composition during peak demand, then fuel stream stability is improved, but O2 content increases causing catalyst deactivation
Solution Approach 1:
The oxidation catalyst selectively extracts and removes O2 from the fuel stream through catalytic reaction. This extraction process maintains fuel stream stability by allowing air addition while eliminating the harmful O2 that would otherwise cause catalyst deactivation
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
The system effectively prevents coking and extends the life of the fuel cell stack by maintaining consistent pre-reformation across varying natural gas compositions, enabling operation with propane and ethane without deactivating the catalysts, thus improving the system's efficiency and longevity.
Implementation Method 1
providing the fuel stream to an oxidation catalyst to catalyze a reaction between any O2 included in the fuel stream and at least one of H2 and CO included in the fuel stream
Implementation Method 2
oxidation catalyst to reduce an O2 content of fuel received from the CPOx reactor
Implementation Method 3
providing the fuel stream to a hydrogenation catalyst to catalyze a saturation reaction between any unsaturated hydrocarbons included in the fuel stream and the H2 included in the fuel stream
Implementation Method 4
providing the fuel stream from the hydrogenation catalyst to the reforming catalyst to generate a reformed fuel
Implementation Method 5
reforming catalyst configured to at least partially reform fuel received from the oxidation catalyst
Implementation Method 6
a catalytic partial oxidation (CPOx) reactor configured to partially oxidize the fuel during startup of the system
Data Source
AI summary
A fuel cell system and method for using a peak shaving gas, the system including: a fuel inlet configured to receive fuel from a fuel source; a catalytic partial oxidation (CPOx) reactor configured to at least partially oxidize the fuel during startup of the system; a blower configured to provide air to the CPOx reactor; a gas analyzer configured to determine a composition of fuel provided to the CPOx reactor from the fuel inlet; an oxidation catalyst configured to reduce an O2 content of fuel received from the CPOx reactor; a reforming catalyst configured to partially reform fuel received from the oxidation catalyst; and a stack of fuel cells configured to generate electricity using fuel received from the reforming catalyst.