Hydrogen-Enriched Fuel Combustion for Low NOx Emissions
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Solution Overview
Problem
Existing power generation systems using hydrogen-enriched fuel gases struggle to reduce NOx emissions efficiently while maintaining operational costs and process efficiency, often requiring costly hydrogen production and additional emission treatment equipment.
Innovation Solution
A system that utilizes a reformer to produce a hydrogen-enriched stream with low hydrogen concentration, combined with a combustion system and recuperator to recycle heat energy, reducing flame temperatures and NOx emissions, and incorporating a separation unit to manage carbon dioxide, thereby enhancing operability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If hydrogen enriched fuel gas is used to reduce NOx emissions, then NOx emissions are reduced, but operational costs increase due to costly hydrogen production
Solution Approach 1:
The patent changes the concentration parameter of hydrogen in the fuel stream, using low concentration hydrogen-enriched fuel gas (e.g., 1-10% hydrogen) instead of high concentration or pure hydrogen. This parameter change achieves NOx reduction while avoiding the high costs associated with producing and handling high-concentration hydrogen, thus resolving the contradiction between emission reduction and operational cost.
2Productivity
If high combustion temperature is used to increase efficiency, then power generation efficiency is improved, but thermal NOx generation increases exponentially
Solution Approach 1:
The patent applies local quality by enriching hydrogen in specific zones or stages of the combustion process rather than uniformly throughout. The low concentration hydrogen-enriched fuel gas is introduced in a manner that creates localized effects on flame temperature and combustion characteristics, allowing efficiency maintenance in certain zones while NOx suppression in others.
Solution Approach 2:
The patent uses partial action by introducing a small amount of hydrogen (low concentration enrichment) rather than full hydrogen replacement. This partial enrichment is sufficient to achieve the desired NOx reduction and efficiency improvement without the excessive costs and technical challenges of complete hydrogen substitution, thus resolving the contradiction between efficiency and emissions.
3Object-generated harmful factors
If equivalence ratio is reduced below 1.0 to lower flame temperature and reduce NOx, then NOx generation decreases, but flame stability deteriorates and flame may blow out
Solution Approach 1:
The patent changes the chemical composition parameter of the fuel by introducing hydrogen-enriched fuel gas. Hydrogen has superior flame stability characteristics and a broader flammability range compared to conventional fuels. Even at low concentrations (1-10% enrichment), hydrogen acts as a stabilizing agent that prevents flame blowout and maintains stable combustion, thus resolving the contradiction between NOx reduction and flame stability.
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 system effectively reduces NOx emissions by 6 ppm to 3 ppm or less, meets stringent emissions standards, and lowers operational costs by recycling heat energy, making it suitable for retrofitting existing systems.
Implementation Method 1
a reformer configured to receive a fuel and produce a hydrogen-enriched stream
Implementation Method 2
a combustion system configured to burn the hydrogen enriched-stream and produce electricity and an exhaust stream
Implementation Method 3
a recuperator configured to recover heat from the exhaust stream, wherein the recovered heat is recycled back to the reformer
Data Source
AI summary
A system for reducing NOx emissions, includes a reformer configured to receive a fuel and produce a hydrogen-enriched stream, a combustion system configured to burn the hydrogen enriched-stream and produce electricity and an exhaust stream, and a recuperator configured to recover heat from the exhaust stream, wherein the recovered heat is recycled back to the reformer.