Solid Fuel Burner Air Guide Angles for NOx and CO Control
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Solution Overview
Problem
Existing solid fuel burners face challenges in reducing unburned combustibles and CO emissions while suppressing NOx generation, as the enlargement of the reducing flame region with low oxygen concentration leads to slower mixing of solid fuel with secondary and tertiary air.
Innovation Solution
A solid fuel burner design featuring a solid fuel nozzle, secondary air nozzle, tertiary air nozzle, and guide members that deflect air flows radially at specific angles, with a seal air introduction member and deflection member to optimize air flow and mixing, reducing the reducing flame region and enhancing combustion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the reducing flame region with low oxygen concentration is enlarged, then NOx generation is suppressed, but mixing of solid fuel with secondary air and tertiary air is slowed down, increasing unburned combustibles and CO
Solution Approach 1:
The air supply system is segmented into primary air, secondary air, and tertiary air with distinct functions. The secondary air nozzle and tertiary air nozzle are positioned at different locations and angles to create staged combustion zones, allowing the reducing flame region to be enlarged for NOx suppression while maintaining efficient fuel mixing through the primary air carrier gas
Solution Approach 2:
Different regions of the burner are assigned different air concentrations and flow characteristics. The secondary air is introduced at a first angle to create a low-oxygen reducing zone for NOx suppression, while tertiary air is introduced at a second angle greater than the first angle to enhance mixing and combustion efficiency in the subsequent zone, achieving both NOx reduction and high combustion completeness
2Object-generated harmful factors
If the reducing flame region with low oxygen concentration is enlarged, then NOx generation is suppressed, but the size of the flame region increases
Solution Approach 1:
The burner employs dynamic flow control through multiple air nozzles with different injection angles. The secondary air nozzle introduces air at a first angle to extend the reducing flame region for NOx suppression, while the tertiary air nozzle introduces air at a greater second angle to compact the overall flame structure, dynamically balancing flame volume and NOx reduction
Solution Approach 2:
The air injection system operates in multiple spatial dimensions with secondary air introduced at a first angle and tertiary air at a second angle greater than the first angle. This multi-dimensional air distribution creates a staged combustion process that enlarges the reducing zone in one dimension while controlling the overall flame volume through angular distribution in another dimension
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 effectively reduces unburned combustibles and CO emissions while maintaining NOx suppression, balancing the effects of reducing flame size and combustion efficiency, and preventing ash adhesion to the burner throat.
Implementation Method 1
a secondary air guide member for guiding a flow of the secondary air outwardly in a radial direction, which is positioned on an outer peripheral portion at a distal end of the solid fuel nozzle; and one or more tertiary air guide members for guiding a flow of the tertiary air outwardly in the radial direction at a first angle with respect to a central axis of the solid fuel burner
Implementation Method 2
a seal air deflection member for deflecting the seal air outwardly in the radial direction is provided on a distal end portion of the seal air introduction member
Implementation Method 3
a solid fuel nozzle for ejecting mixed fluid of solid fuel and primary air
Data Source
AI summary
A solid fuel burner to be inserted into a burner throat bored in a wall portion of a furnace, comprising: a solid fuel nozzle for ejecting mixed fluid of solid fuel and primary air; a secondary air nozzle for ejecting secondary air; a tertiary air nozzle for ejecting tertiary air; a secondary air guide member for guiding a flow of the secondary air outwardly in a radial direction; and one or more tertiary air guide members for guiding a flow of the tertiary air outwardly in the radial direction at a first angle with respect to a central axis (C) of the solid fuel burner, wherein a distal end position (X2) of each of the tertiary air guide members in an axial direction of the solid fuel burner is at a closer side of the furnace than a distal end position (X1) of the secondary air guide member.