Crosslinked Polynorbornene Membranes for Natural Gas Separation
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Solution Overview
Problem
Current membranes used for natural gas upgrading lack high selectivity and durability, particularly in separating smaller hydrocarbons like methane from heavier hydrocarbons, and suffer from decreased performance due to aging.
Innovation Solution
Crosslinked alkoxysilyl polynorbomene homopolymer membranes are developed, which maintain high permeability while achieving enhanced selectivity and resistance to aging through sol-gel initiated crosslinking and the incorporation of alkoxysilyl moieties, allowing for improved separation of methane from heavier hydrocarbons like propane and butane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If glassy polymer membranes are used for natural gas separation, then methane permeability is high, but hydrocarbon selectivity is insufficient
Solution Approach 1:
The patent modifies the polymer structure by introducing rubbery segments with specific glass transition temperatures and free volume characteristics. This changes the physical parameters of the membrane material to achieve simultaneous high methane permeability and improved hydrocarbon selectivity, resolving the contradiction between quantity of substance and manufacturing precision
Solution Approach 2:
The invention creates composite membrane structures combining glassy polymer matrices with rubbery polymer segments. This composite approach allows the membrane to exhibit both high gas permeability from the glassy phase and enhanced selectivity from the rubbery phase, addressing the contradiction between methane permeability and hydrocarbon selectivity
2Manufacturing precision
If membrane selectivity is heightened to improve separation performance, then permeability decreases
Solution Approach 1:
The patent introduces rubbery segments with specific properties (glass transition temperature between -100°C to 0°C, specific free volume characteristics) at local regions within the polymer matrix. These localized regions provide selective pathways for gas molecules while maintaining overall membrane permeability, resolving the contradiction between selectivity and permeability
3Manufacturing precision
If glassy polymer membranes are used for separation, then initial separation performance is achieved, but performance decreases due to aging
Solution Approach 1:
The patent incorporates rubbery segments with specific glass transition temperatures below operating temperature into the membrane structure beforehand. These segments act as cushioning elements that prevent free volume collapse and maintain membrane performance over time, compensating for aging effects before they occur and extending membrane life while preserving separation performance
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
The crosslinked alkoxysilyl polynorbomene homopolymer membranes demonstrate significantly higher selectivity for propane over methane (up to double the previous maximum) and improved resistance to aging, maintaining high permeability and selectivity in natural gas upgrading applications.
Implementation Method 1
producing a crosslinked alkoxysilyl polynorbomene homopolymer through sol-gel initiated crosslinking of the alkoxysilyl modified polynorbomene homopolymer
Implementation Method 2
Most membranes used in the gas separation field are derived from glassy polymers... these glassy polymers have high permeation of methane relative to propane, butane, and other gases
Implementation Method 3
Aging occurs from collapse of free volume, which tends to cause lower permeability
Data Source
AI summary
Embodiments for a crosslinked alkoxysilyl polynorbornene homopolymer and methods of making crosslinked alkoxysilyl polynorbornene homopolymer are provided, where the method comprises polymerizing through addition polymerization or ring opening metathesis polymerization a norbornene monomer comprising an alkoxysilyl moiety in the presence of a catalyst to produce an alkoxysilyl modified polynorbornene homopolymer, and producing a crosslinked alkoxysilyl polynorbornene homopolymer through sol-gel initiated crosslinking of the alkoxysilyl modified polynorbornene homopolymer at ambient conditions, or acid-catalyzed conditions.