Gas Separation Membrane Module With Telescoping Tube for Fiber Shrinkage
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Solution Overview
Problem
Polymeric fiber membranes used in gas separation modules suffer from durability issues due to plasticization and fiber shrinkage, leading to stress on tubesheets and reduced module performance and life.
Innovation Solution
A gas separation module with a telescoping core tube that stabilizes tubesheets and provides slack in fibers, preventing damage from shrinkage, and includes distinct passages for separate handling of permeate and retentate gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymeric fiber membranes are used in gas separation modules, then gas separation performance is improved, but fiber durability deteriorates due to plasticization and shrinkage
Solution Approach 1:
The patent applies beforehand cushioning by providing a support structure (tubesheets with support ribs or a rigid matrix) that preemptively counteracts the shrinkage forces generated when polymeric fibers undergo plasticization. This support structure acts as a cushion that absorbs and distributes the stress, preventing fiber collapse and maintaining structural integrity throughout the module's operational life.
Solution Approach 2:
The patent employs composite materials by combining the polymeric separation fibers with a rigid support structure (such as metal tubesheets with support ribs or a rigid porous matrix). This composite construction allows the system to benefit from both the selective permeability of the polymeric fibers and the dimensional stability of the rigid support, thereby resolving the contradiction between separation performance and durability.
2Reliability
If fiber membranes are exposed to acid gas atmospheres with heavy hydrocarbons and aromatics, then gas separation capability is maintained, but fiber plasticization increases leading to shrinkage
Solution Approach 1:
The patent converts the harmful effect of plasticization into a manageable phenomenon by designing a support structure that anticipates and accommodates fiber shrinkage. The rigid support framework transforms the potentially destructive shrinkage force into a controlled compression against the support, preventing fiber collapse while maintaining separation capability even in harsh acid gas environments.
Solution Approach 2:
The rigid support structure (tubesheets with ribs or rigid matrix) serves as an intermediary between the polymeric fibers and the harsh operating environment. It mediates the interaction by providing mechanical stability that protects the fibers from excessive shrinkage and deformation caused by exposure to acid gases, heavy hydrocarbons, and aromatic compounds.
3Area of stationary object
If modules are arranged vertically to save space, then space utilization is improved, but stress on tubesheets from fiber shrinkage increases
Solution Approach 1:
The patent applies segmentation by dividing the tubesheet into multiple regions with integrated support ribs or by using a modular rigid matrix structure. This segmentation distributes the shrinkage-induced stress across multiple localized support points rather than concentrating it on the entire tubesheet surface, thereby reducing overall stress while maintaining vertical compactness.
Solution Approach 2:
The patent implements local quality by providing enhanced local support through ribs or reinforced zones positioned strategically on the tubesheet where fiber bundles are anchored. This localized reinforcement addresses the stress concentration issue at critical points without requiring overall tubesheet thickening, thus maintaining space efficiency in vertical arrangements while managing stress effectively.
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
Enhances the efficiency and longevity of gas separation modules by preventing fiber damage and tubesheet movement, allowing operation at higher pressures and maintaining gas separation performance.
Implementation Method 1
Various polymers have the property that they allow different gases to flow through, or permeate, the membrane, at different rates
Implementation Method 2
The gas that preferentially flows through the membrane wall is called the 'permeate' gas
Implementation Method 3
One or more components of the feed gas may dissolve into the polymeric structure
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3B
AI summary
A gas separation module includes hollow polymeric fibers held between a pair of tubesheets. The tubesheets are mounted to a core tube, and the distance between the tubesheets is maintained constant. The core tube is formed in telescoping sections, such that the fibers are attached to the tubesheets when the core tube is in its extended position, and the core tube is then collapsed, forming slack in the fibers. The core tube includes two distinct channels, connected to receive permeate and retentate gas streams, and to carry these streams to outlet ports while keeping the streams separate. Because the tubesheets are affixed to the core tube, the tubesheets do not move under the influence of gas pressure in the module. The slack in the fibers compensates for shrinkage of the fibers, prolonging the life of the module.