Permeate Spacer Flow Patterns to Reduce Pressure Drop and Fouling
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Solution Overview
Problem
Spiral-wound membrane elements face issues with flow restriction and membrane fouling due to the presence of porous feed spacers, which also contribute to pressure drop and biological growth, particularly in pressure retarded osmosis (PRO), forward osmosis (FO), and reverse osmosis (RO) applications.
Innovation Solution
The use of printed or deposited features, such as posts, islands, and lines, in the permeate spacer to create arbitrary flow paths and protrusions that replace or reduce the need for conventional feed spacers, allowing for lower resistance to fluid flow and minimizing membrane fouling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a porous feed spacer is used to maintain open axial flow, then flow uniformity is improved, but pressure drop and flow restriction increase
Solution Approach 1:
The patent removes the porous feed spacer component entirely and replaces it with printed flow channel patterns directly on the membrane surface. This extraction eliminates the spacer-induced pressure drop while maintaining flow distribution through the printed channel geometry that guides axial flow without the obstruction of a separate porous component.
Solution Approach 2:
The patent merges the feed spacer function with the membrane surface by printing flow channel patterns directly onto the membrane. This integration combines the separation function of the membrane with the flow distribution function of the spacer, eliminating the need for a separate spacer component and reducing overall flow resistance.
2Length of moving object
If a porous feed spacer is used to maintain spacing, then spacing for axial flow is improved, but membrane fouling increases
Solution Approach 1:
The patent extracts and removes the porous feed spacer that serves as a fouling substrate. By eliminating this separate component, the patent removes the surface where biological growth, scale formation, and particle capture occur, thereby reducing membrane fouling while maintaining necessary spacing through the printed channel structure.
Solution Approach 2:
The patent applies local quality by creating specific flow channel patterns with controlled geometry directly on the membrane surface. These printed channels provide localized spacing and flow guidance exactly where needed, while the rest of the membrane surface remains clean and free from spacer-induced fouling areas.
3Productivity
If conventional woven permeate spacer fabric is used, then permeate removal is achieved, but flow resistance is high
Solution Approach 1:
The patent replaces the mechanical woven fabric structure of conventional permeate spacers with a printed pattern system on the membrane surface. This substitution uses printed flow channel geometries to guide permeate removal pathways, reducing flow resistance while maintaining the necessary permeate collection and removal function through optimized channel design.
Data Source
AI summary
Embodiments of the present invention provide the integration of arbitrary flow directing patterns, deposited or integrated on or into the porous permeate spacer in a spiral-wound membrane separation element.