Aeration Lance and Impeller Flow Conversion
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Solution Overview
Problem
Conventional systems for injecting air into a slurry in flue gas desulfurization systems suffer from reduced mass transfer efficiency due to flooding, which shortens the life of impellers and decreases system performance.
Innovation Solution
A lance and impeller system where the lance is positioned on the outflow side of the impeller with a vane assembly and conduit configuration that directs gas flow away from the impeller, converting swirling flow into longitudinal flow to enhance mass transfer and reduce flooding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If air lance is positioned near impeller to enhance mass transfer, then oxygen uptake rate increases, but flooding occurs and impeller life decreases
Solution Approach 1:
The harmful interaction between air flow and impeller blades is extracted and eliminated by positioning the air lance outlet on the impeller outflow side, where the air stream is directed away from the impeller rotation path, preventing flooding while maintaining mass transfer efficiency
Solution Approach 2:
The air lance is positioned in a different spatial dimension relative to the impeller, specifically on the outflow side rather than near the suction side or center, creating a three-dimensional arrangement that separates the air injection zone from the impeller blade path while maintaining effective gas-liquid contact
2Productivity
If impeller creates strong swirling flow to enhance mixing, then mass transfer is promoted, but low pressure region causes air to flow backwards and flood the impeller
Solution Approach 1:
The low pressure region and swirling flow that cause flooding are converted into beneficial forces by positioning the air lance on the outflow side, where the swirling flow directs air away from the impeller, transforming the harmful backflow into a useful flow direction that enhances mass transfer without flooding
Solution Approach 2:
Instead of positioning the air lance to counteract the swirling flow, the invention inverts the approach by positioning it to utilize the swirling flow direction, placing the lance on the outflow side where the natural swirl directs air away from the impeller, preventing flooding while maintaining mixing efficiency
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 system improves mass transfer efficiency by reducing flooding and increasing turbulence, leading to higher oxygen uptake rates and longer impeller lifespan.
Implementation Method 1
Operation of the impeller creates swirling flow, which forms a low pressure region at the center of the swirl or vortex
Implementation Method 2
Gas exiting lance 102 may flow backwards into the low pressure region toward impeller 104
Implementation Method 3
the lance and impeller system directs flow from the impeller and converts at least a portion of a swirling flow from the impeller into longitudinal flow
Implementation Method 4
air is injected into the slurry to oxidize the calcium sulfite into calcium sulfate (CaSO4)
Data Source
AI summary
A system for introducing air into a slurry in a flue gas desulphurization process includes a stationary lance and an impeller. The lance include an outlet portion and a vane assembly. The outlet directs air away from the impeller. The vane assembly may produce turbulence and may convert a portion of the swirling flow from the impeller into longitudinal flow.