Pulse Aeration Housing for Membrane Defouling at Lower Air Cost
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Solution Overview
Problem
Existing aeration systems for liquid filtration membranes are costly and require improved performance to effectively remove contaminants from the membrane surfaces.
Innovation Solution
A pulse aeration system with a chamber housing and gas feed conduit that releases gas intermittently to defoul hollow-fiber or flat sheet membranes, utilizing a riser conduit with a barrier and apertures positioned to optimize gas distribution and minimize occlusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous aeration is used to clean membrane surfaces, then cleaning effectiveness is improved, but operational cost increases
Solution Approach 1:
The aeration system operates intermittently through periodic gas discharge events rather than continuously. Gas is discharged in pulses when the liquid level in the common chamber drops below the apertures, creating bubbles that rise and clean the membrane surfaces. This periodic operation maintains cleaning effectiveness while significantly reducing air consumption and operational costs compared to continuous aeration.
2Ease of operation
If gas inlet apertures are positioned low in the chamber wall, then gas distribution is improved, but aperture occlusion by contaminants increases
Solution Approach 1:
The common chamber acts as an intermediary between the gas source and the membrane surfaces. Gas is introduced into the common chamber and accumulates as the liquid level drops, allowing contaminants to settle away from the gas inlet apertures. When the liquid level falls below the apertures, clean gas is discharged through the riser conduits to the membranes. This intermediary chamber design maintains good gas distribution while preventing aperture occlusion by keeping the apertures above the liquid level during discharge.
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 reduces operational costs by intermittent gas release, effectively cleaning membrane surfaces while maintaining consistent bubble distribution and preventing aperture occlusion, even with high particulate contaminants.
Implementation Method 1
Some aeration systems employ an intermittent siphon effect, so as to release bubbles only intermittently
Implementation Method 2
aeration systems have been employed in the water tank to release bubbles of air that rise and interact with the membranes to clean the contaminants off the membranes
Data Source
AI summary
A pulse aeration system for an immersed membrane filtration system is provided. The aeration system includes a housing defining chambers, and a gas feed conduit. Each chamber includes a riser conduit having a barrier to release gas up the riser conduit when a gas level in the chamber reached below the barrier, for release of the gas into the tank so as to defoul at least one hollow-fiber membrane or flat sheet membrane in the tank. Each chamber has a bottom that is open to permit retentate in each chamber. The housing includes a first wall defining a gas inlet aperture into each chamber. The gas inlet aperture is positioned at an elevation that is within 3 cm of a bottom edge of the barrier. The gas feed conduit is in fluid communication with the first wall gas inlet apertures.