Separation Membrane Module Evaluation Using Degradation Gas
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Solution Overview
Problem
Current methods for evaluating separation membrane modules are limited in accuracy due to the inability to detect defects smaller than the molecular size of inspection gases or liquids used, and these methods often require costly and environmentally burdensome substances, as well as inefficient regeneration processes that can degrade membrane performance.
Innovation Solution
A method involving the use of a performance degradation gas to reduce permeance, followed by an evaluation fluid with a molecular size less than or equal to 0.40 nm, to accurately measure flow rates through defects in the separation membrane module, allowing for precise evaluation and regeneration of the membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inspection gas or liquid with large molecular size (e.g., CF4 or Fluorinert) is used to prevent permeation through zeolite membrane, then the amount of inspection substance permeating through the membrane is reduced, but the ability to detect small defects in the sealer is limited
Solution Approach 1:
The patent introduces a porous base material as an intermediary layer between the sealer and the zeolite membrane. This base material has larger pore sizes than the zeolite membrane, allowing inspection gases or liquids to access and detect defects in the sealer without being blocked by the zeolite membrane's small pores. The intermediary layer thus enables defect detection while preventing unwanted permeation through the functional membrane.
Solution Approach 2:
The separation membrane module is segmented into distinct functional layers: a sealer layer for sealing, a porous base material layer for inspection access, and a zeolite membrane layer for separation. This segmentation allows each layer to perform its specific function independently, enabling defect detection in the sealer without compromising the integrity or performance of the zeolite membrane.
2Measurement precision
If inspection gas or liquid with large molecular size is used, then permeation through zeolite membrane is suppressed, but environmental burden and collection cost increase
Solution Approach 1:
The porous base material acts as an intermediary that enables effective leak inspection using environmentally friendly inspection substances. By providing an alternative pathway through its larger pores, it allows the use of common gases like nitrogen or air instead of environmentally harmful substances like CF4 or Fluorinert, thus reducing environmental burden while maintaining inspection accuracy.
3Measurement precision
If liquid is supplied to wet the tubular separation membrane before leak inspection, then gas permeation through small pores is reduced, but liquid removal time increases and regeneration efficiency is limited
Solution Approach 1:
The porous base material serves as an intermediary structure that eliminates the need for liquid wetting of the zeolite membrane. Its larger pore size allows it to function as the inspection pathway without requiring liquid saturation, thus avoiding the time-consuming liquid removal step while still enabling accurate leak detection through its permeable structure.
Solution Approach 2:
The inspection function is extracted from the zeolite membrane and assigned to the porous base material. This extraction allows the zeolite membrane to remain dry and functional, eliminating the need for liquid removal and regeneration processes, thus reducing time loss and improving operational efficiency.
4Measurement precision
If liquid is adsorbed on the inside of small pores of tubular separation membrane, then liquid removal processing time increases, but membrane separation performance may be degraded after inspection
Solution Approach 1:
The porous base material acts as an intermediary inspection medium that does not require adsorption into the zeolite membrane's small pores. This eliminates the need for lengthy desorption and regeneration processes, maintaining high productivity and membrane performance after inspection.
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 approach enables accurate characterization of separation membrane modules by increasing the permeance reduction rate, reducing the need for large molecular size inspection fluids, and simplifying the regeneration process, thereby improving evaluation efficiency and membrane performance.
Implementation Method 1
supplying a performance degradation gas to a primary side of a separation membrane, the performance degradation gas having a property of reducing permeance of the separation membrane
Implementation Method 2
supplying an evaluation fluid to the primary side of the separation membrane and measuring a flow rate of the evaluation fluid to a secondary side of the separation membrane
Data Source
AI summary
A method of evaluating a separation membrane module includes a step of supplying a performance degradation gas having a property of reducing permeance of a separation membrane to a primary side of the separation membrane, and a step of, after the previous step, supplying an evaluation fluid to the primary side of the separation membrane to measure a flow rate of the evaluation fluid to a secondary side of the separation membrane.