Pressure Retarded Osmosis Module End-Face Ports
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Solution Overview
Problem
Existing osmosis modules designed for low-pressure applications are structurally unsuitable for pressure retarded osmosis due to the high pressures involved, leading to inefficiencies and potential clogging issues, as well as uneven solvent transfer across hollow fibers.
Innovation Solution
The design of an osmosis module with a pressure vessel containing a central structure and hollow fiber semipermeable membranes, where the draw stream flows lengthwise and parallel to the central structure, reducing radial concentration gradients and enhancing solvent transfer uniformity across all membranes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If draw inlet and draw outlet ports are provided in the surrounding wall of the housing, then fluid communication with the draw stream is achieved, but the structural strength of the housing is weakened
Solution Approach 1:
The draw ports are extracted from the surrounding wall and relocated to the end-faces of the housing. This removes the structural weakness from the critical pressure-containing wall while maintaining the necessary fluid communication function through the end-faces, which are better suited for port placement.
Solution Approach 2:
The draw ports are moved from a radial position (in the surrounding wall) to an axial position (in the end-faces). This dimensional change allows the ports to be placed in a location that does not compromise the circumferential structural integrity of the housing while still providing access to the draw stream.
2Power
If high pressure is applied to maximize energy generation, then energy output is improved, but the risk of clogging and structural failure increases
Solution Approach 1:
The housing material is selected to have specific local properties suitable for high-pressure operation, and the port placement in the end-faces creates localized flow paths that reduce clogging risk in the wall structure. The semipermeable membranes also have specific local quality properties to handle high pressure while maintaining selectivity.
Solution Approach 2:
The housing is designed with end-face port placement that pre-establishes proper flow paths before operation begins, preventing clogging from the outset. The structural design anticipates high-pressure conditions and incorporates features to prevent failure before it occurs.
3Productivity
If draw stream flows radially through the housing, then flow distribution is achieved, but radial concentration gradients cause uneven solvent transfer
Solution Approach 1:
Instead of allowing the draw stream to flow radially through the housing wall, the design inverts the approach by placing draw ports in the end-faces to create axial flow through the hollow fibers. This reverses the conventional radial flow pattern and eliminates the resulting radial concentration gradients that cause uneven solvent transfer.
Solution Approach 2:
The draw stream flow path is segmented into distinct regions: an first region where flow is through the hollow fibers and a second region where flow is around the hollow fibers. This segmentation allows controlled flow distribution that prevents excessive concentration gradients while maintaining productive solvent transfer.
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
This configuration improves energy efficiency and overall energy output by ensuring more even solvent transfer and extending the operational life of the fibers by reducing clogging and pressure loss.
Implementation Method 1
The membrane allows solvent to pass from the less concentrated solution (with lower osmotic pressure) to the more concentrated solution (with higher osmotic pressure) by osmosis
Implementation Method 2
The permeate is transported from the low pressure side to the high pressure side through the membrane due to the difference in osmotic pressure
Data Source
AI summary
An osmosis module for pressure retarded osmosis comprising a pressure vessel having a first draw port and a second draw port. The first draw port is provided in a first end-face of the pressure vessel and is in fluid communication with a central structure. A plurality of hollow fibre semipermeable membranes are received within a fibre region of the osmosis module, and are provided around the central structure. In a first lengthwise region of the osmosis module, the draw stream flow between the first draw port and the fibre region via the central structure. In a second lengthwise region of the osmosis module, the flow path which the draw stream flows between the draw ports, is confined to the fibre region and extends substantially parallel to the central structure. The second region extends along a majority of the length of the fibre region.