Gas Separation Membrane Stages for Purity and Yield
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Solution Overview
Problem
Existing gas separation processes struggle to achieve high purities for both permeate and retentate gases simultaneously without requiring recompression or additional purification steps, leading to inefficiencies and increased costs.
Innovation Solution
A chain of three membrane separation stages with partial pressure differentials generated by compressors and vacuum pumps, where the concentration of permeate gases is increased in the feed stream, reducing the need for further purification and minimizing methane emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a one-stage membrane separation step is used, then high purity can be achieved in the product stream, but the quality of the permeate-side offgas stream is low and methane yield is reduced
Solution Approach 1:
The single membrane separation step is divided into multiple stages. The first stage produces a permeate stream that is further processed in a second stage, allowing the system to achieve both high product purity and high methane yield by segmenting the separation process into sequential steps with different objectives.
2Manufacturing precision
If multistage connection arrangements with recompression are used, then permeate purity and methane yield can be improved, but additional energy expenditure and financial investment are required
Solution Approach 1:
A heat exchanger is introduced as an intermediary component between the first and second membrane stages. This heat exchanger recovers energy from the warm permeate stream of the first stage to pre-cool the feed stream entering the second stage, thereby reducing the overall energy requirement for compression and cooling operations.
3Manufacturing precision
If higher pressure ratios are applied, then better separation outcome is achieved, but the range becomes selectivity-limited and cannot be influenced by pressure ratio
Solution Approach 1:
The separation process is segmented into two stages with different pressure ratios. The first stage operates at a moderate pressure ratio to achieve initial separation, while the second stage operates at a higher pressure ratio to achieve final high purity. This segmentation allows each stage to operate in its optimal pressure range, maintaining adaptability while achieving excellent separation outcomes.
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 allows for the simultaneous achievement of high purity permeate and retentate gases with reduced capital costs and energy consumption, eliminating the need for additional purification steps and minimizing methane emissions.
Implementation Method 1
By means of a gas separation membrane, it is possible to separate gas mixtures on the basis of different permeabilities (=flow rate per unit time, unit area, pressure differential and layer thickness) of the individual gases in a polymer
Data Source
AI summary
The invention relates to a specific apparatus, more particularly a chain of gas separation membrane modules, for separation of gas mixtures into two fractions each of elevated purity.