Solid Oxide Fuel Cell Gas Circuit Anode Pressure Control

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Solution Overview

Problem

Existing solid oxide fuel cell systems face reliability and service life issues due to high pressure differences between the air and combustion sides, which can lead to damage or failure, especially when using fuels like hydrocarbons and recirculating anode gas with conventional recirculation methods.

Innovation Solution

A gas circuit design where the gas delivery device is placed upstream of the dividing device in the anode gas section, allowing for recirculation of anode gas without excessively increasing anode pressure, by using a blower or ejector to supply additional mediums like water or steam in the recirculation section.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a blower or ejector is used to recirculate anode gas in the gas circuit, then fuel gas treatment efficiency is improved, but anode pressure rises significantly above pressure losses of downstream components

Engineering Contradiction:
Improvefuel gas treatment efficiencyVSAvoidanode pressure
Core Design Contradiction:
ProductivityVSStress or pressure

Solution Approach 1:

The patent inverts the conventional arrangement by placing the dividing device upstream of the blower/ejector instead of downstream. This reversal allows the pressure-building device to operate on the combined gas streams rather than having to overcome the full pressure loss of the residual gas path alone, thereby maintaining anode pressure within safe limits while still achieving effective fuel gas treatment.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces a dividing device as an intermediary component that splits the anode gas stream before it enters the blower/ejector. This intermediary arrangement allows separate control of recirculation and residual gas paths, enabling the blower to maintain appropriate pressure in the recirculation line without excessively pressurizing the anode gas space.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If recirculation rate is increased to provide sufficient hydrogen, carbon monoxide and carbon dioxide for reforming, then fuel processing efficiency is improved, but pressure in the anode gas space increases excessively

Engineering Contradiction:
Improvefuel processing efficiencyVSAvoidanode gas space pressure
Core Design Contradiction:
ProductivityVSStress or pressure

Solution Approach 1:

The patent segments the anode gas stream into recirculation and residual portions using a dividing device positioned upstream of the blower. This segmentation allows independent optimization of each stream: the recirculation stream can be pressurized to achieve high fuel processing efficiency, while the residual stream bypasses the pressure-building section, preventing excessive overall anode pressure.

Inventive Principle:
Principle #1Segmentation

3Use of energy by moving object

If the conveying device is positioned downstream of the dividing device, then power consumption is reduced, but anode pressure control becomes difficult and reliability decreases

Engineering Contradiction:
Improvepower consumptionVSAvoidfuel cell reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent inverts the conventional positioning arrangement, placing the conveying device upstream of the dividing device rather than downstream. This inversion prioritizes reliability over minimal power consumption, ensuring that the conveying device can maintain proper pressure control in the recirculation line without risking anode damage, while accepting the associated energy cost.

Inventive Principle:
Principle #13The other way round (Inversion)

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 design maintains low anode pressure, reducing the risk of damage and ensuring high reliability and extended service life with minimal impact on electrical efficiency, despite higher power consumption.

Implementation Method 1

a further medium, such as water or steam, is added to the recirculation stream in the recirculation section by means of an ejector, a nozzle or a jet scrubber

Methodology Applied
Scientific EffectEjector effect: Injector

Implementation Method 2

a further medium, such as water or steam, is added to the recirculation stream in the recirculation section by means of an ejector, a nozzle or a jet scrubber

Methodology Applied
Scientific EffectNozzle effect: De Laval Nozzle

Data Source

PatentEP3084869B1Gas circuit for a solid oxide fuel cell system and a solid oxide fuel cell system
Publication Date: 2020.02.12 THYSSENKRUPP MARINE SYST GMBH
  • EP3084869B1 patent drawingFigure 1~2
  • EP3084869B1 patent drawingFigure 3~4

AI summary

The invention relates to a gas circuit for a solid oxide fuel cell system, which comprises an anode gas segment in which emerging anode gas flows out of a gas chamber of an anode of a solid oxide fuel cell, and a recirculation segment for recirculating at least a portion of the anode gas back to a combustion gas processing device arranged in the gas circuit and in which fuel for the solid oxide fuel cell is processed into combustion gas, wherein a conveying device for recirculating the anode gas, and a distribution device, which divides the anode gas into a recirculation stream and a residual gas stream discharging from the gas circuit, are arranged in the gas circuit, wherein the conveying device is arranged upstream of the distribution device in the anode gas segment. The invention further relates to a solid oxide fuel cell with a gas circuit.