Boiler Lance with Cooling System for Selective Non-Catalytic Reduction
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Solution Overview
Problem
In large boilers, the reagent used for selective non catalytic reduction often evaporates within the hose before reaching the nozzle, preventing effective injection and mixing with flue gas, leading to low NOx removal efficiency.
Innovation Solution
A boiler design with a lance protruding from a side tubed wall, equipped with a hose drive mechanism and a cooling system to minimize reagent evaporation, along with adjustable nozzle positioning for optimized injection, ensures effective reagent delivery and mixing with flue gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hose is used to deliver reagent from the top of the boiler, then the reagent can reach the injection point, but the reagent evaporates within the hose before reaching the nozzle
Solution Approach 1:
The lance is repositioned from a vertical top-wall configuration to a horizontal side-wall configuration. This dimensional change allows the reagent to be delivered through a shorter horizontal path, reducing exposure time to high temperatures and minimizing evaporation loss while maintaining reliable delivery to the injection point
Solution Approach 2:
The lance is pre-cooled by circulating cooling water through internal channels before reagent injection. This preliminary cooling action creates a thermal barrier that prevents reagent evaporation during delivery, ensuring the reagent reaches the nozzle in its intended state
2Productivity
If the lance is positioned further into the inner space to optimize injection area, then NOx removal efficiency improves, but reagent evaporation risk increases
Solution Approach 1:
The cooling water circulation system is activated before reagent injection to pre-cool the lance. This preliminary thermal protection allows the lance to be positioned deeper into the hot inner space for optimized injection without risking reagent evaporation, as the cooling system maintains appropriate temperature conditions throughout the delivery path
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 reduces reagent evaporation and enhances NOx removal efficiency by maintaining reagent integrity and optimizing injection patterns within the boiler, improving overall NOx conversion rates.
Implementation Method 1
the lance is provided with a cooling system
Implementation Method 2
the reagent passing through the hose could evaporate within the hose before it reaches the nozzle
Implementation Method 3
the flue gas can be passed through a catalyzer, for the NOx to be converted into N2 and H2O
Data Source
AI summary
The boiler (1) has side tubed walls (2) enclosing an inner space (3) and a device for selective non catalytic reduction (7). The device for selective non catalytic reduction (7) has a lance (8) carrying a hose (9) having at least a nozzle (10) and a hose drive mechanism (11) for driving the hose within the lance. The lance (8) protrudes into the inner space (3) from a side tubed wall (2) of the boiler (1).