Co-Firing Combustor Layout for Stable Liquid Ammonia Combustion
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Solution Overview
Problem
Conventional combustors using hydrocarbon fuels produce carbon dioxide and nitrogen oxides, and the use of liquid ammonia as a fuel faces challenges due to low flammability and heating value, leading to unstable combustion.
Innovation Solution
A method of co-firing a combustor with gas fuel in multiple zones using head end and axial fuel stage injectors, transitioning to ammonia combustion with an atomizer, stabilized by cross flow and quenching effects, to achieve efficient ammonia combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If liquid ammonia is used as fuel to reduce CO2 emissions, then environmental performance is improved, but combustion stability deteriorates due to low flammability and heating value
Solution Approach 1:
The patent uses gas fuel (natural gas) as an intermediary substance to stabilize ammonia combustion. The gas fuel is injected through AFS injectors to provide reliable combustion that supports the inherently unstable ammonia flame, allowing ammonia to be burned effectively while maintaining combustion stability throughout the combustion zones.
Solution Approach 2:
The patent changes the physical state and injection parameters of ammonia by using an atomizer to convert liquid ammonia into fine droplets. This parameter change increases the surface area to volume ratio of ammonia, improving vaporization and mixing with air, thereby enhancing combustion stability despite ammonia's low flammability characteristics.
2Reliability
If multiple fuel injection systems are used to stabilize ammonia combustion, then combustion stability is improved, but device complexity increases
Solution Approach 1:
The patent designs the AFS injectors to serve multiple functions: they inject gas fuel for stable combustion and simultaneously provide airflow that supports ammonia vaporization and mixing. This multi-functionality reduces the need for separate dedicated components for each function, thereby limiting the increase in device complexity while achieving improved combustion stability.
3Object-affected harmful factors
If ammonia is combusted alone to maximize carbon reduction, then environmental benefit is improved, but combustion efficiency deteriorates due to low heating value
Solution Approach 1:
The patent merges ammonia combustion with gas fuel combustion in a co-firing arrangement. The gas fuel and ammonia are burned together in the combustion zones, combining the high heating value of gas fuel with the zero-carbon advantage of ammonia. This merging allows the system to maintain high combustion efficiency while significantly reducing carbon emissions compared to using either fuel alone.
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 enables stable and efficient combustion of ammonia, reducing carbon dioxide and nitrogen oxides, while maintaining combustion stability and efficiency across varying load ranges.
Implementation Method 1
an ammonia atomizer aimed into the combustion liner to combust ammonia in at least the primary combustion zone
Implementation Method 2
The cross flow of the first AFS injector set stabilizes combustion of ammonia
Implementation Method 3
the second AFS injector set provides a quenching effect
Data Source
AI summary
Co-firing a combustor with gas fuel and ammonia using various approaches is disclosed. Each method fires a gas fuel in a primary combustion zone using a head end fuel nozzle, in a secondary combustion zone using a first axial fuel stage (AFS) injector set, and/or a tertiary combustion zone using a second AFS injector set over a particular combustor load range, and transitions to firing with ammonia using an ammonia atomizer. The methods may transition to ammonia combustion alone or ammonia with gas fuel combustion. The cross flow of the first AFS injector set stabilizes combustion of ammonia, and the second AFS injector set provides a quenching effect, each of which contributes to efficient ammonia combustion with or without gas fuel combustion.