External Mixer-Eductor-Oxidizer Layout for Fuel Cell Pressure Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing internal mixer-eductor-oxidizers (MEO) in fuel cell systems are too large to fit within the enclosure, necessitating a need for a partially or completely external configuration that minimizes pressure drop and allows for space to control internal pressures while reducing costs and heat loss.
Innovation Solution
A fuel cell system with a mixer-eductor-oxidizer (MEO) partially or completely external to the enclosure, connected via non-bellowed and bellowed pipes, and supported by an integrated enclosure or movement means to accommodate thermal expansion, with optional recycle blowers and oxidant gas recycling to optimize gas flow and pressure control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an internal mixer-eductor-oxidizer is used to minimize pressure drop and control internal pressures, then pressure control efficiency is improved, but the device size becomes too large to fit within the fuel cell module enclosure
Solution Approach 1:
The MEO is divided into multiple functional sections (mixing section, eduction section, oxidation section) that are distributed across different locations. The mixing section is positioned outside the enclosure while the oxidation section is placed inside, allowing each section to perform its function optimally without requiring the entire device to be internally housed.
Solution Approach 2:
The MEO configuration transitions from a purely internal three-dimensional arrangement to a distributed arrangement that utilizes both internal and external spaces. By extending the mixing section externally and using strategic internal placement of the oxidation section, the system achieves effective pressure control without the volume constraints of a fully internal configuration.
2Adaptability or versatility
If bellowed pipes are used to connect the external MEO to the fuel cell module, then thermal expansion accommodation is improved, but the cost and heat loss increase
Solution Approach 1:
Instead of using bellowed pipes throughout the entire connection, the patent applies thermal expansion accommodation locally at specific points where expansion occurs. Expansion joints or flexible connection sections are positioned only at the MEO connection points and fuel cell interface locations, while the majority of the piping uses standard rigid connections that minimize heat loss.
Solution Approach 2:
The patent uses simplified expansion accommodation designs that replicate the essential function of bellows without their complex structure. Standard expansion joints or flexible couplings are used that provide the necessary thermal expansion capability while having smoother surfaces and simpler geometries that reduce heat loss compared to traditional bellowed pipes.
3Reliability
If the MEO is positioned close-coupled to the fuel cell module to minimize pressure drop, then pressure control efficiency is improved, but space for eduction is reduced
Solution Approach 1:
The MEO components are nested within the fuel cell module structure in a space-efficient arrangement. The oxidation section is positioned inside the enclosure while the mixing section extends externally, utilizing the internal volume of the fuel cell module housing. This nested arrangement maintains close coupling for pressure control while creating the necessary space for eduction operations.
Solution Approach 2:
The MEO is designed with movable or adjustable components that allow the eduction section to expand into available space when needed. The close-coupled configuration includes flexible mounting or adjustable positioning that enables the eduction function to access sufficient space dynamically while maintaining the close proximity required for pressure drop minimization.
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 external MEO configuration reduces pressure drop, minimizes heat loss, and lowers costs by eliminating the need for large bellowed pipes, allowing for efficient gas mixing and pressure control, while facilitating easy maintenance and reducing thermal stress.
Implementation Method 1
one of the main functions of the MEO is to educt fuel from the fuel cell system to control internal pressure requirements
Implementation Method 2
the anode-exhaust must be completely mixed with air
Implementation Method 3
movement means mounted on a bottom surface of the mixer-eductor-oxidizer, the movement means configured to facilitate movement of the mixer-eductor-oxidizer towards and away from the fuel cell module in response to stress on the non-bellowed pipe
Implementation Method 4
a bellowed pipe equipped with a bellows that is configured to compress or extend in response to stress on the bellowed pipe
Implementation Method 5
The MEO oxidizes unconverted anode fuel, preheats inlet air, recycles carbon dioxide (CO2) to the cathode
Implementation Method 6
unused fuel in the exhaust gas exiting from the anode-side of the fuel cell stack is oxidized with incoming fresh air to heat the air
Data Source
AI summary
A fuel cell system includes a fuel cell module having an enclosure configured to house a fuel cell stack that comprises a plurality of fuel cells; and a mixer-eductor-oxidizer that is at least partially external to the enclosure of the fuel cell module, the mixer-eductor-oxidizer being configured to process oxidant supply gas and deliver oxidant gas to a cathode side of the fuel cell stack.