Multi-Stage Membrane Gas Separation With Permeate Recirculation
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Solution Overview
Problem
Existing gas permeation devices for separating gas mixtures into product gas and offgas face challenges of low product gas quality and yield, along with high energy requirements and costly system design, particularly due to the need for oversized systems and energy-intensive compression.
Innovation Solution
A device with at least two membrane units and a compressor, where the retentate of one unit is fed into the next, and the permeate is used to pressurize the system, allowing for smaller membrane unit dimensions and reduced energy consumption by recycling permeate streams, thereby enhancing product gas yield and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a one-stage membrane unit is used to separate pressurized feed gas into retentate and permeate, then the system structure is simple, but the product gas quality and yield are low with high energy requirements
Solution Approach 1:
The patent divides the single membrane separation process into multiple stages with multiple membrane units arranged in series and parallel configurations. The feed gas is sequentially processed through different membrane units, with each unit contributing to progressive separation. This segmentation allows the system to achieve high product gas yield and quality while maintaining reasonable structural complexity through modular design.
2Productivity
If the pressurized permeate of a first membrane unit is used as feed gas for a second membrane unit, then the product gas yield is improved, but the product gas quality remains low and energy requirement increases due to compression
Solution Approach 1:
The patent combines multiple membrane units with different selectivity characteristics in a hybrid configuration. Some units operate in series to progressively separate components, while others are arranged in parallel to handle different gas streams simultaneously. This merging of multiple separation pathways achieves high product gas yield without requiring excessive compression, as each unit contributes to the overall separation efficiency.
Solution Approach 2:
The patent utilizes membrane units with varying selectivity parameters and operating conditions. By changing parameters such as membrane material properties, pressure differentials, and flow rates across different units, the system optimizes separation efficiency at each stage. This allows high yield to be achieved without proportionally increasing energy consumption through compression.
3Productivity
If the permeate of the second membrane unit is circulated back to mix with pressurized feed gas, then higher product gas yield is achieved and less selective membranes can be used, but the system dimensions and energy requirement increase due to recirculation
Solution Approach 1:
The patent implements dynamic flow distribution where permeate streams are selectively recirculated to specific membrane units based on real-time separation needs. Rather than uniform recirculation throughout the system, the design dynamically routes flows to optimize separation efficiency in each unit. This reduces the overall system volume required for recirculation infrastructure while maintaining high product gas yield.
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 achieves higher product gas yield and more efficient energy utilization while reducing system dimensions and costs, allowing for the use of less selective membranes and extending the service life of certain membrane units.
Implementation Method 1
Device and method for separating a gas mixture into product gas and offgas by way of gas permeation
Data Source
AI summary
The invention relates to a device for separating a gas mixture into product gas and offgas by way of gas permeating on, comprising at least two membrane units (1) and (2) and a condenser (3) connected upstream of the first membrane unit (1), which membrane units (1) and (2) have a gas inlet (1a, 2a), a retentate outlet (1b, 2b) and a permeate outlet (1c, 2c), wherein the retentate outlet (1b) of the first membrane unit (1) is connected to the gas inlet (2a) of the second membrane unit (2), the permeate outlet (2c) of the second membrane unit (2) is connected on the intake side to the condenser (3) or the gas supply leading into the condenser, and the condenser (3) is connected to the gas inlet (1a) of the first membrane unit (1), the connection in each case being by way of lines, product gas is obtained via the permeate outlet (2a) and offgas via the retentate outlet (1c), wherein the permeate outlet (4c) of an upstream membrane unit (1) is connected to the gas supply of the condenser (3) by way of lines, wherein at least one further membrane unit (5) is connected upstream of the membrane unit (4) by way of a line connection of the retentate outlet (5b) of the further membrane unit (5) to the gas inlet (4a) of the membrane unit (4), and additional product gas is obtained via the retentate outlet (4b) and additional offgas is obtained via the permeate outlet (5c). The present invention further relates to such a method.