Rotating Torus Filter for Sludge Dewatering
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Solution Overview
Problem
Conventional filtration methods, including crossflow filtration systems, struggle to efficiently dewater and treat Mature Fine Tailings (MFT) and other slurry or sludge forms due to the buildup of filter cakes, which limits their filtrate flux and effectiveness in managing large volumes of contaminated water from oil sands tailings ponds and similar industrial waste.
Innovation Solution
A rotatable torus filter design with a partially submerged, rotating filter surface and custom pore structure that creates micro-vortices to prevent filter cake buildup, utilizing a shear lift effect to separate solids from liquids, allowing continuous and increased filtrate flow, and incorporating a system for vapor and condensate collection and recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional crossflow filtration systems are used to dewater MFT and sludge, then filtration is achieved, but filter cake buildup limits filtrate flux and reduces effectiveness
Solution Approach 1:
The filter surface is rotated at controlled speeds to create dynamic relative motion between the filter and the liquid-sludge mixture. This rotation prevents static filter cake buildup by continuously renewing the filtration surface, maintaining high flux rates and sustained filter effectiveness throughout operation.
Solution Approach 2:
The rotation of the filter surface creates mechanical disturbance and shear forces that prevent filter cake consolidation. This mechanical action keeps the filter surface active and prevents the formation of impermeable cake layers that would otherwise reduce filtrate flux and effectiveness.
2Productivity
If filter rotation speed is increased to prevent filter cake buildup, then filtrate flux improves, but energy consumption increases
Solution Approach 1:
The system optimizes rotation speed as a controllable parameter, operating at speeds sufficient to prevent filter cake buildup but not excessively high to waste energy. The patent identifies specific rotation speed ranges that achieve the desired balance between maintaining filtrate flux and minimizing energy consumption.
3Productivity
If conventional stationary filters are used, then equipment complexity is low, but filter cake accumulation requires frequent backwashing and reduces productivity
Solution Approach 1:
The stationary filter is replaced with a rotating filter mechanism that continuously renews the filtration surface. This dynamic approach eliminates the need for periodic backwashing operations, achieving continuous filtration capability despite the added complexity of the rotation mechanism.
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 torus filter design significantly enhances filtrate flux, enabling faster and more efficient dewatering of MFT and other sludges, reducing the accumulation of filter cakes and improving the management of large volumes of contaminated water, while also allowing for the recycling of water and heat energy.
Implementation Method 1
The motion can be by moving the filter, or having the liquid be moving. Beier's experimental apparatus used liquid moving through a perforated pipe, and relied on the buildup of a filter cake over the filter pores
Implementation Method 2
A rotatable torus filter design with a partially submerged, rotating filter surface and custom pore structure that creates micro-vortices to prevent filter cake buildup
Implementation Method 3
the filter comprising an upper half and a lower half, with the lower half comprising a permeable membrane, the permeable membrane comprising at least one pore configured to pass a filtrate while excluding solids
Data Source
AI summary
A rotatable filtration apparatus includes a partially submergible, rotatable filter in a shape of a torus having a central axis of rotation, the filter comprising an upper half and a lower half, with the lower half comprising a permeable membrane, the permeable membrane comprising at least one pore configured to pass a filtrate while excluding solids, a rotation motor configured to rotate the filter about the central axis of rotation, an anchor configured to anchor the rotatable filter in a body of liquid, and a pump to extract the filtrate from the filtrate chamber into a filtrate line.