Multi-Pressure Membrane Separation for Methane Purity Without Recompression
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Solution Overview
Problem
Membrane separation systems for gas mixtures face challenges in meeting product purity and recovery requirements while incurring high compression and recompression costs due to the recycling of permeate streams, especially in multistage configurations.
Innovation Solution
The method involves splitting a pressurized gas mixture into multiple streams at successively lower pressures and processing them through separate membrane systems at different pressure levels, eliminating the need for upstream recycling by combining permeate and retentate with fresh feed for subsequent membrane systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If permeate streams are recycled through multistage membrane systems, then product purity requirements can be met, but compression and recompression costs increase significantly
Solution Approach 1:
The system divides the single feed stream into multiple separate feed streams at different pressure levels, each processed by its own membrane system. This segmentation eliminates the need to recycle permeate streams through multiple compression stages, thereby reducing compression costs while maintaining product purity through the distributed separation process
Solution Approach 2:
The invention transitions from a single-stage sequential process to a multi-pressure-level parallel process. By operating membrane systems at different pressure levels simultaneously and combining their outputs, the system achieves the same separation effectiveness without the energy-intensive recompression required in traditional recycled configurations
2Use of energy by moving object
If single stage membrane separation is used, then compression costs are reduced, but product purity and recovery requirements cannot be met
Solution Approach 1:
Rather than using a single complex stage, the system segments the separation process into multiple simpler stages operating at different pressure levels. Each stage handles a portion of the feed and produces product at its operating pressure, eliminating the need for high-cost compression while achieving required purity through combined output
Solution Approach 2:
The system varies the pressure parameter across different membrane systems to optimize separation performance. By operating at multiple pressure levels simultaneously, the system achieves high product purity without requiring the high compression costs associated with single-stage high-pressure systems
3Productivity
If permeate is recycled to enhance methane recovery, then product recovery improves, but additional compression and equipment complexity are required
Solution Approach 1:
The system segments the feed stream into multiple independent streams that are processed simultaneously at different pressure levels. This eliminates the need for permeate recycling infrastructure and associated compression equipment, reducing system complexity while maintaining methane recovery through the distributed separation approach
Solution Approach 2:
Each membrane system operates independently using its own feed stream at its designated pressure level, producing product that can be combined with other systems' output. This self-contained operation eliminates the need for complex recycling loops and recompression equipment, reducing overall system complexity
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 reduces compression and recompression costs, enhances methane recovery, and achieves high product purity by optimizing the membrane separation process across varying pressures.
Implementation Method 1
The principle behind membrane separation is based on different molecules having different rates of permeation ('permeability') through a membrane. More specifically, some molecules readily pass through the membrane (i.e., to the permeate side), while other molecules do not readily pass through the membrane
Implementation Method 2
The driving force behind this process is a difference in partial pressure, that is, the concentration multiplied by the pressure. The gas molecules move from the side of higher partial pressure to lower partial pressure
Data Source
AI summary
A process and/or system for processing a pressurized gas mixture by membrane separation. Portions of the pressurized gas mixture are withdrawn and provided as a plurality of pressurized gas streams at successively lower pressures. Each portion, provided as a respective pressurized gas stream, is provided for processing in a respective membrane system, each of which is at a different pressure level. Partially purified streams produced by one or more membrane systems are provided for processing at lower pressure levels (e.g., where they are combined with one of the pressurized gas streams). Accordingly, costs associated with recycle compression are reduced and/or eliminated.