Integral Reactor System for Solid Oxide Fuel Cells
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Solution Overview
Problem
High-temperature solid oxide fuel cells face challenges with carbon deposition from hydrocarbon fuels, requiring external reformers that are complex and inefficient, and necessitate additional oxygen sources to mitigate carbon formation.
Innovation Solution
An integral reactor system within the fuel cell, featuring a fuel delivery element with a recirculation device, pre-reforming section, and reforming section, which converts hydrocarbon fuels to thermally stable species like methane and hydrogen, reducing the need for external oxygen and minimizing carbon formation by recirculating anode exhaust gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If external steam reformers are used to prepare fuel, then carbon formation is mitigated, but the system becomes large and complex requiring separate water sources
Solution Approach 1:
The patent combines the reforming function and fuel delivery function into a single integrated reactor system located within the fuel cell stack. The fuel delivery element serves dual purposes: delivering fuel to the anode and performing reforming reactions internally, eliminating the need for separate external reformers and water management systems.
Solution Approach 2:
The fuel delivery element performs self-reforming using the fuel itself and recirculated anode exhaust gas as the oxidant source. The system utilizes internally recirculated oxygen-rich anode exhaust gas to drive the reforming reactions, eliminating the need for external water sources or separate oxidant supply systems.
2Productivity
If external reformers with blowers or ejectors are used, then fuel preparation is achieved, but efficiency falls off at high pressure ratios requiring high pressure operation
Solution Approach 1:
The patent removes the external blower or ejector components from the system by integrating the recirculation function directly into the fuel delivery element. The recirculation device uses the natural flow of fuel and anode exhaust gas through the fuel delivery passage, eliminating the need for high-pressure blowers or ejectors and their associated energy losses.
3Quantity of substance
If hydrocarbon fuels are used directly, then energy density is maximized, but carbon deposits form through pyrolysis or catalytic routes
Solution Approach 1:
The patent performs preliminary reforming of the hydrocarbon fuel within the fuel delivery element before the fuel reaches the anode. By converting the hydrocarbon to smaller species like methane, carbon monoxide, and hydrogen through reforming reactions with recirculated anode exhaust gas, the system prevents subsequent carbon deposition while maintaining the energy benefits of hydrocarbon 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 enhances fuel cell efficiency, reduces the risk of carbon deposition, and eliminates the need for external oxygen sources, resulting in a more compact and efficient fuel delivery system that can scale with fuel cell systems of any size.
Implementation Method 1
an anode exhaust gas recirculation device configured to cause recirculation of oxygen-rich anode exhaust gas formed in the anode-side cavity of the fuel cell through a length of the fuel delivery passage of the fuel delivery element
Implementation Method 2
a reforming section configured to reform a hydrocarbon fuel to a smaller species in the presence of an oxidant
Implementation Method 3
The fuel delivery element may include a reactor configured to convert a higher hydrocarbon to a smaller thermally stable species, such as methane, hydrogen, and carbon monoxide
Implementation Method 4
Solid oxide fuel cells (SOFCs) generate electricity through the spontaneous transport of an oxygen ion across a strong chemical potential gradient
Implementation Method 5
Solid oxide fuel cells (SOFCs) generate electricity through the spontaneous transport of an oxygen ion across a strong chemical potential gradient
Implementation Method 6
The anode exhaust gas recirculation device may comprise a constriction in the one or more walls forming the fuel passage of the fuel delivery element and one or more suction bores downstream of the constriction, the suction bores open to the anode-side cavity of the fuel cell. In this manner, anode exhaust gas is drawn into the fuel delivery device through the suction bores by suction created by the high velocity jet issuing from the constriction
Data Source
AI summary
A reactor system is integrated internally within an anode-side cavity of a fuel cell. The reactor system is configured to convert higher hydrocarbons to smaller species while mitigating the lower production of solid carbon. The reactor system may incorporate one or more of a pre-reforming section, an anode exhaust gas recirculation device, and a reforming section.