Boiler Pre-Ignition System for NOx Reduction
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Solution Overview
Problem
Existing solutions for reducing NOx and SOx emissions in coal-fired boilers are costly and inefficient, with high capital and operating expenses associated with in-furnace and post-combustion technologies.
Innovation Solution
A system and method that involves a pre-ignition source positioned within a conduit leading to the boiler's combustion area, where a portion of the fuel is pre-ignited before entering the combustion zone, reducing the amount of pollutants emitted during the combustion process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If in-furnace technology such as low NOx burner/overfire air systems or gas reburn systems is used, then NOx emissions are reduced, but capital and operating costs increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-igniting a portion of the fuel (10-50% of total fuel flow) in a separate pre-ignition zone before it enters the main combustion chamber. This pre-ignited fuel then mixes with the remaining unignited fuel and promotes more complete combustion in the main chamber, reducing NOx emissions without requiring complex post-combustion treatment systems. The pre-ignition source is positioned to ignite fuel as it flows through the combustion chamber, creating a more efficient burn that lowers emissions while avoiding the high costs of conventional NOx reduction technologies.
2Object-generated harmful factors
If post-combustion technology such as selective noncatalytic reduction or selective catalytic reduction is used, then NOx emissions are reduced, but capital and operating costs increase significantly
Solution Approach 1:
The patent extracts the ignition function from the main combustion system and places it in a separate pre-ignition zone within the fuel flow path. By positioning the pre-ignition source to ignite a portion of the fuel before it enters the main combustion chamber, the system achieves more complete combustion and lower NOx emissions without requiring external post-combustion treatment systems like SCR or SNCR. This extraction of the ignition function eliminates the need for expensive catalytic converters or reduction agents.
3Object-generated harmful factors
If a pre-ignition source is positioned in the conduit to pre-ignite fuel, then NOx emissions are reduced and operational efficiency is maintained, but the system complexity increases
Solution Approach 1:
The patent merges the pre-ignition function with the existing fuel delivery system by positioning the pre-ignition source within the fuel conduit or combustion chamber where fuel already flows. The pre-ignited fuel mixes with unignited fuel in the same combustion chamber, combining two functions (pre-ignition and main combustion) into a single integrated system. This merging approach reduces system complexity compared to separate pre-ignition and combustion systems, while still achieving the emission reduction benefits.
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 pre-ignition system effectively reduces NOx emissions by pre-igniting a portion of the fuel under substoichiometric conditions, enhancing the release of fuel volatiles and improving emission reduction across the boiler's load range, while maintaining operational efficiency and cost-effectiveness.
Implementation Method 1
A pre-ignition source positioned in the conduit operates to pre-ignite at least a portion of the fuel flowing through the conduit
Data Source
AI summary
A system and method for reducing emissions from a boiler. A boiler generally has a combustion area. The system further includes a fuel pipe for delivering fuel. The system further includes a conduit. A bore extends through the conduit. The bore of the conduit is in fluid communication with the fuel pipe and the combustion area of the boiler. A pre-ignition source is positioned in the conduit. The pre-ignition source operates to pre-ignite at least a portion of the fuel flowing through the conduit.