In-Block Fuel Cell Reforming for Thermal Stress Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fuel cell systems with in-block reforming face challenges in maintaining thermal equilibrium and reducing thermal stresses, which can lead to material degradation and performance reduction, despite the use of heat exchangers and reformers.
Innovation Solution
A fuel cell system configured for in-block reforming (IBR) with a pre-reformer and anode ejector that supplies a stream of fuel with a high recycle ratio, directly reforming fuel within the fuel cell stack without an external reformer, and optionally using a heat exchanger to manage oxidant temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat exchanger is introduced into the fuel cell system to maintain thermal equilibrium of oxidant, then the oxidant temperature is stabilized, but the device complexity increases
Solution Approach 1:
The patent combines the reformer and heat exchanger functions into a single integrated component. The reformer serves dual purposes: reforming hydrocarbon fuel and acting as a heat exchanger to transfer heat from combustion products to oxidant, thereby stabilizing oxidant temperature without requiring a separate heat exchanger component.
Solution Approach 2:
The reformer is designed to perform multiple functions simultaneously: fuel reforming, heat generation through combustion, and heat transfer to oxidant. This multi-functionality eliminates the need for separate dedicated components for each function, reducing overall system complexity while maintaining thermal equilibrium.
2Productivity
If an external reformer is used to reform fuel before supplying to fuel cell, then fuel reforming is effective, but the device complexity and cost increase
Solution Approach 1:
The patent merges the external reformer with the fuel cell stack to create an integrated in-block reforming system. The reforming process occurs within the fuel cell block itself, combining what were previously separate components into a single unified system that maintains effective fuel reforming while reducing component count.
Solution Approach 2:
The reformer is nested within the fuel cell stack structure, with the reforming process occurring inside or integrated with the fuel cell blocks. This nesting approach allows the reforming function to be embedded within the existing fuel cell architecture, eliminating the need for a separate external reformer while maintaining reforming effectiveness.
3Duration of action of stationary object
If in-block reforming is implemented to reduce thermal stresses, then temperature gradients are reduced and system lifespan is extended, but the manufacturing precision requirements increase
Solution Approach 1:
The patent implements localized reforming zones within the fuel cell stack, where reforming occurs at specific locations rather than uniformly throughout. This local quality approach allows for controlled temperature distributions that reduce thermal stresses while managing the complexity of manufacturing precision requirements through targeted rather than universal high-precision fabrication.
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 configuration reduces temperature gradients within the fuel cell stack, leading to more uniform current distribution, longer system lifespan, and eliminates the need for an external reformer, thereby reducing costs and degradation.
Implementation Method 1
In steam reforming of natural gas—sometimes referred to as steam methane reforming (SMR)—steam reacts with methane at high temperatures (600° C.-1100° C.) and in the presence of a metal-based catalyst to yield carbon monoxide and hydrogen (CH4+H2O⇄CO+3H2)
Implementation Method 2
The heat exchanger may be supplied with combustion products to create a reaction that produces heat. The reaction may occur in the heat exchanger or in another component such as, e.g., a combustor located upstream of the heat exchanger.
Implementation Method 3
A fuel cell stack is an electrochemical system in which a fuel (such as hydrogen) is reacted with an oxidant (such as oxygen) at high temperature to generate electricity
Data Source
AI summary
A fuel cell system and corresponding methods are provided. The fuel cell system includes a fuel cell stack configured for in-block reforming, as well as a pre-reformer. The fuel cell stack may include a plurality of fuel cells. The fuel cell stack may also include a fuel supply manifold, a fuel exhaust manifold, an oxidant supply manifold, and an oxidant exhaust manifold. The fuel supply manifold may be configured to receive fuel, and to supply the fuel to the fuel cell stack for in-block reforming. The fuel exhaust manifold may be configured to expel fuel exhaust from the fuel cell stack. The oxidant supply manifold may be configured to receive an oxidant and to supply the oxidant to the fuel cell stack for in-block reforming. The oxidant exhaust manifold may be configured to expel oxidant exhaust from the fuel cell stack.