Ammonia-Fueled SOFC System with Exhaust Recycling

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Solution Overview

Problem

High temperature fuel cell systems face inefficiencies and environmental concerns when using traditional fuels, particularly in terms of carbon oxide emissions and fuel utilization, especially when operating with ammonia as a fuel source.

Innovation Solution

The implementation of a recycling system for the high temperature fuel cell stack exhaust stream, utilizing separation and conversion devices to create a purified recycled fuel stream, which includes the use of separators to remove nitrogen and water, and ammonia reactors to condition the fuel inlet stream, thereby enhancing fuel utilization and reducing environmental impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional fuels are used in high temperature fuel cell systems, then the system can operate, but carbon oxide emissions are generated causing environmental concerns

Engineering Contradiction:

Improvecarbon oxide emissionsVSAvoidfuel source options

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent changes the fuel parameter from traditional hydrocarbon fuels to ammonia fuel, fundamentally altering the chemical composition to eliminate carbon oxide emissions while maintaining fuel cell operation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the exhaust stream containing nitrogen and water into a purified recycled fuel stream by removing these components, transforming what would be waste into a beneficial recycled fuel source

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If ammonia is used as fuel source, then carbon oxide emissions are eliminated, but nitrogen and water content in exhaust stream increases

Engineering Contradiction:

Improvecarbon oxide emissionsVSAvoidnitrogen and water content

Core Design Contradiction:

Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The patent extracts and removes nitrogen and water components from the exhaust stream through separation devices, isolating these substances from the recycled fuel stream to maintain fuel quality

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent discards nitrogen and water from the exhaust stream while recovering and recycling the hydrogen-rich portion back to the fuel inlet, maximizing fuel utilization

Inventive Principle:

Principle #34Discarding and recovering

3Device complexity

If exhaust stream is recycled directly without purification, then system complexity is reduced, but fuel utilization efficiency decreases

Engineering Contradiction:

Improveseparation and conversion devicesVSAvoidfuel utilization efficiency

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent implements continuous recycling of the purified exhaust stream back to the fuel inlet, maintaining continuous useful action by repeatedly utilizing the hydrogen-rich components rather than single-pass consumption

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The patent introduces feedback by recycling the purified exhaust stream back to the fuel inlet, creating a closed-loop system where the output is continuously fed back to improve overall fuel utilization

Inventive Principle:

Principle #23Feedback

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 approach increases the performance of the fuel cell stack by recycling hydrogen-rich streams, reduces nitrogen and water content, and eliminates carbon oxide emissions, making ammonia a viable, efficient, and environmentally friendly fuel option for solid oxide fuel cell systems.

Implementation Method 1

a separator may separate hydrogen from nitrogen and any other remaining fuel exhaust stream components and remove nitrogen from the recycled fuel cell stack exhaust stream

Methodology Applied

Scientific EffectPhysical separation:

Implementation Method 2

a water separator may remove water from the recycled fuel cell stack exhaust stream

Methodology Applied

Scientific EffectPhase separation:

Implementation Method 3

an ammonia reactor and hydrogen separator may be used to condition the fuel inlet stream of the high temperature fuel cell stack

Methodology Applied

Scientific EffectChemical reaction:

Implementation Method 4

Fuel cells are electrochemical devices which can convert energy stored in fuels to electrical energy efficiencies

Methodology Applied

Scientific EffectElectrochemical conversion: Fuel Cell

Data Source

PatentUS8916300B2Ammonia fueled SOFC system

Publication Date: 2014.12.23 BLOOM ENERGY CORP

AI summary

Systems and methods are provided in which ammonia is used as a fuel source for solid oxide fuel cell systems. In the various aspects a high temperature fuel cell stack exhaust stream is recycled through one or more separation or conversion devices to create a purified recycled fuel exhaust stream that is recycled back into the fuel inlet stream of the high temperature fuel cell stack. In various aspects a nitrogen separator may remove nitrogen from the recycled fuel cell stack exhaust stream, a water separator may remove water from the recycled fuel cell stack exhaust stream, and/or an ammonia reactor and hydrogen separator may be used to condition the fuel inlet stream of the high temperature fuel cell stack. In a further aspect a molten carbonate fuel cell and/or Sabatier reactor may be used to condition the fuel inlet stream of the high temperature fuel cell stack.