Three-Layer Feed Spacer Structure for Reverse Osmosis Pressure Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Concentration polarization and increased differential pressure in reverse osmosis filter modules due to turbulent flow and foulant accumulation, leading to reduced efficiency and increased cleaning costs.
Innovation Solution
A feed spacer with a three-layered structure comprising strands of different thicknesses and orientations to minimize turbulent flow and foulant accumulation, including a first set inclined at 10°-80°, a second set at 100°-170°, and a third set parallel to the water flow, with the third set having a larger thickness than the others.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diamond-shaped feed spacer is used to generate turbulent flow, then concentration polarization is alleviated, but differential pressure increases and foulants accumulate
Solution Approach 1:
The feed spacer is divided into three distinct sets of strands (first set, second set, third set) with different orientations and thicknesses. This segmentation allows each set to perform specific functions: the first and second sets generate controlled turbulence to alleviate concentration polarization, while the third set (parallel to flow direction with larger thickness) minimizes pressure loss and prevents foulant accumulation by maintaining smoother flow paths in the bulk water region.
Solution Approach 2:
Different regions of the feed spacer are designed with locally optimized properties. The strands in the first and second sets (crossing each other at angles) have smaller thickness to create turbulence near the membrane surface, while the third set of strands (parallel to flow) has larger thickness to reduce resistance in the bulk flow region. This local differentiation resolves the contradiction by applying turbulence-generating geometry where needed while maintaining smooth flow paths where turbulence would be harmful.
2Reliability
If turbulent flow is generated by the feed spacer, then concentration polarization near the membrane is reduced, but flow obstruction occurs due to differential pressure
Solution Approach 1:
The feed spacer structure is segmented into three functional sets: the first and second sets of crossing strands generate localized turbulence to reduce concentration polarization, while the third set of parallel strands provides low-resistance flow paths that maintain high bulk flow rates. This segmentation enables simultaneous achievement of turbulence where needed and minimal flow obstruction in the bulk region.
Solution Approach 2:
The spacer employs local quality differentiation where strand thickness and orientation are optimized for specific regions. Smaller thickness strands in the first and second sets create turbulence locally at the membrane interface, while larger thickness strands in the third set (parallel to flow) minimize pressure drop in the bulk flow region, thereby maintaining high productivity while reducing concentration polarization.
3Productivity
If the feed spacer generates turbulent flow, then mass transfer is improved, but cleaning frequency increases due to foulant accumulation
Solution Approach 1:
The feed spacer is segmented into three sets with different configurations. The first and second sets generate turbulence to improve mass transfer and reduce concentration polarization, while the third set (parallel to flow direction with larger thickness) creates smooth flow paths that minimize foulant accumulation by reducing flow obstruction and differential pressure, thereby extending cleaning cycles.
Solution Approach 2:
Different regions of the feed spacer have locally optimized strand properties. The first and second sets use smaller thickness strands arranged at angles to generate turbulence for improved mass transfer near the membrane, while the third set uses larger thickness strands parallel to flow to minimize flow obstruction and foulant deposition in the bulk region, reducing the need for frequent cleaning.
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
Reduces pressure loss and foulant accumulation, enhancing the efficiency and stability of the reverse osmosis filter module by promoting laminar flow and maintaining effective membrane area.
Implementation Method 1
the feed spacer not only secures a flow path between the separation membranes, but also generates a turbulent flow in the raw water flow to alleviate the concentration polarization occurring near the reverse osmosis membrane
Implementation Method 2
the reverse osmosis is called an osmosis phenomenon, in which two solutions having a difference in concentration are separated by a semi-permeable membrane
Implementation Method 3
the reverse osmosis is called an osmosis phenomenon, in which two solutions having a difference in concentration are separated by a semi-permeable membrane
Implementation Method 4
the feed spacer has an effect of minimizing the pressure loss by suppressing the occurrence of turbulent flow of raw water
Data Source
AI summary
Provided is a feed spacer having a three-layered structure, and a reverse osmosis membrane filter module including the same, where the feed spacer includes a first set of a plurality of strands that are positioned in parallel; a second set of a plurality of parallel strands provided to cross the first set; and a third set of a plurality of parallel strands positioned in parallel with a raw water flow direction, where at least one of the first set and the second set consists of strands having a smaller thickness than that of the strands constituting the third set.