Atomizer Nozzle Lance for Flue Gas Mixing
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Solution Overview
Problem
Existing devices for mixing fluids with large gas flows in flue gas ducts face challenges with direct injection of liquid reducing agents, as they often result in deposit formation on mixer elements and duct walls due to unevaporated droplets, leading to increased mixing path lengths and risk of damage.
Innovation Solution
The device employs a nozzle lance with at least two atomizer nozzles inclined counter to the gas flow direction, ensuring vaporized components enter flow vortices while unevaporated droplets are diverted, using 2-component nozzles with auxiliary mediums like compressed air or steam to generate a fine droplet spectrum and prevent deposit formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid reducing agent is injected directly into flue gas flow on the back of a mixer element, then mixing path is shortened, but deposit formation occurs on mixer elements and duct walls due to unevaporated droplets
Solution Approach 1:
The injection system is segmented into multiple atomizer nozzles that create a fine droplet spectrum, dividing the liquid reducing agent into smaller droplets that evaporate more efficiently and reduce deposit formation while maintaining short mixing path
Solution Approach 2:
An auxiliary atomizing medium (compressed air or steam) is introduced as an intermediary to enhance droplet atomization and evaporation, allowing liquid reducing agent to be injected closer to the mixer element without causing deposits
2Object-generated harmful factors
If nozzle is located far away from mixer element to prevent deposit formation, then deposit risk is reduced, but mixing path length increases
Solution Approach 1:
The physical parameters of the liquid reducing agent are changed through atomization processes, transforming it from a coarse liquid stream into a fine aerosol with high surface area to volume ratio, enabling complete evaporation within short mixing paths and allowing nozzle placement close to the mixer element
3Productivity
If atomizer nozzles are inclined counter to flow direction, then vaporized components enter flow vortices for efficient mixing, but unevaporated droplets may follow different trajectories
Solution Approach 1:
Different regions of the injected spray are given different qualities: the fine vaporized components are directed into the flow vortices for efficient mixing, while the larger unevaporated droplets follow inertial trajectories that bypass the mixer element, with each region optimized for its specific behavior
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 configuration significantly reduces deposit formation, allows for shorter mixing paths, and ensures efficient integration of vaporized reducing agents into the flue gas flow, enhancing mixing efficiency and preventing damage to mixer elements and ducts.
Implementation Method 1
equipped with at least two atomizer nozzles that are inclined counter to the flow direction of the gas flow
Implementation Method 2
the vaporized gaseous components contained in the jet stream exiting from the atomizer nozzles enter the flow vortices
Implementation Method 3
flow turbulence forming on the mixer element and at least part of the fluid entering this flow turbulence
Implementation Method 4
the NH3 evaporated in the hot flue gas from the liquid reducing agent supplied follows the flue gas flow
Implementation Method 5
the non-evaporated droplet-shaped components do not enter the flow vortices in the vicinity of the mixer disk due to their inertia and the atomizer angle
Implementation Method 6
2-component nozzles with auxiliary mediums like compressed air or steam to generate a fine droplet spectrum
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
In an apparatus for mixing a fluid with a large gas stream (2) flowing in a gas duct, especially for introducing a reducing agent (5a) into a flue gas comprising nitrogen oxides, having at least one metering lance (5) with at least one nozzle (4a; 4b) for the feeding of the fluid, whose axis forms an angle with the flow direction of the gas stream, and at least one flat mixer element which is arranged at a distance from the nozzle and forms an angle with the flow direction of the gas stream, wherein flow eddies (3) are formed at the mixer element and at least some of the fluid gets into these flow eddies, deposit formation is prevented to a substantial extent in the case of direct injection of a liquid as the fluid, especially of a liquid reducing agent, with a short mixing path, in accordance with the invention by providing that, in the case of use of a liquid (5a) as the fluid, the metering lance (4) is equipped with at least two atomizer nozzles (4a, 4b) which are tilted against the flow direction of the gas stream (2) and in opposite directions to one another, such that the atomizer nozzles are assigned to a mixer element (1) with a disk-like design.