Powder Injection Lance for Reducing Agglomeration
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Solution Overview
Problem
Existing systems for activated carbon injection in power plants face limitations due to agglomeration of powdered activated carbon, which reduces the available reactive surface area and contaminant removal efficiency, especially in high-volume, low-concentration flue gases with limited contact time.
Innovation Solution
The development of advanced lance systems with specific nozzle geometries that utilize flow profiles to break agglomerates into primary particle sizes, enhancing dispersion and reactive surface area through local accelerations, particle collisions, boundary interactions, and gas pressure-induced stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If powdered activated carbon is injected into high-volume flue gas, then contaminant removal capacity increases, but particle agglomeration occurs reducing reactive surface area
Solution Approach 1:
The lance divides the powder stream into multiple smaller sub-streams through multiple outlets, preventing particles from clumping together. This segmentation maintains individual particle surface area while increasing total contaminant removal capacity through higher injection rates
Solution Approach 2:
The lance features an inner tubular member with outlets positioned within the flow path of an outer tubular member. This nested configuration allows the inner member to break up agglomerates formed by the outer member's flow, creating a multi-stage dispersion system that preserves reactive surface area at high injection rates
2Productivity
If powder injection rate is increased to maximize contaminant removal, then treatment capacity improves, but agglomeration increases reducing particle dispersion
Solution Approach 1:
The lance creates dynamic flow conditions where gas velocity and turbulence vary across different zones. The inner tubular member is positioned to create high-velocity jets that dynamically break up agglomerates formed by the outer member's lower-velocity flow, maintaining particle dispersion at high injection rates
Solution Approach 2:
The lance uses a three-dimensional nested configuration with outlets at different positions and angles. This spatial arrangement creates multi-directional flow patterns that prevent particles from settling into agglomerates, maintaining dispersion in all dimensions even at high injection rates
3Quantity of substance
If contact time is extended to improve mercury adsorption, then removal efficiency increases, but system complexity and space requirements increase
Solution Approach 1:
The lance uses pneumatic principles to create high-velocity gas flows that enhance mixing and mass transfer between particles and flue gas. This increases the effective reaction rate, allowing shorter contact times while maintaining high mercury removal efficiency
Solution Approach 2:
The lance modifies flow parameters (velocity, turbulence, pressure) to optimize the reaction kinetics. By creating high-velocity turbulent flows, the system increases mass transfer coefficients, compensating for reduced contact time and maintaining removal efficiency without extending residence time
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 approach significantly increases contaminant removal efficiency by maintaining a linear trend of mercury removal with increasing injection rates, reducing agglomeration, and improving particle distribution within the flue gas duct, as demonstrated by increased mercury removal rates in experimental tests.
Implementation Method 1
agglomerates break when they interact with a boundary (physical, static, or dynamic). Fourth, agglomerates break when subjected to gas pressure acting within the agglomerate, which induces sufficient stress in the agglomerate to overcome attractive forces between particles
Implementation Method 2
flow profiles induce the breaking of agglomerates to reduce the average particle size down closer to the primary particle sizes of powder PAC
Implementation Method 3
agglomerates break apart when they interact with other agglomerates in the system
Implementation Method 4
agglomerates break when they interact with a boundary (physical, static, or dynamic)
Implementation Method 5
Once introduced to the process gas, the sorbent adsorbs mercury
Data Source
Figure 1A1~1C2
Figure 2
Figure 3
AI summary
A lance (400) for powder injection resulting in reduced agglomeration, including an outer tubular member (408) having a first end (412), a second end (404), and an inner flowpath extending from the first end to the second end; an inner tubular member (408) having a first end (412), a second end (404), and an inner flowpath (416) extending from the first end to the second end, the inner tubular member disposed within the inner flowpath of the outer tubular member for providing an annular space (410) between the outer tubular member and the inner tubular member; and one or more orifices (418) in the inner tubular member for providing a flowpath between the annular space and the inner flowpath of the inner tubular member. Additional lances, nozzles, systems, and methods are also included.