CHA Zeolite Membrane for CO2 Separation Under Wet Conditions
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Solution Overview
Problem
Conventional zeolite membranes struggle with CO2/N2 and CO2/CH4 separation under wet conditions due to moisture interference, leading to reduced CO2 permeance and increased costs in flue gas treatment and biogas upgrading processes.
Innovation Solution
A CHA zeolite membrane is developed using a synthetic precursor with a controlled Si/Al ratio, optimized hydrophobicity, and defect formation, allowing for high CO2 separation performance even in wet conditions through hydrothermal synthesis with a CHA particle seed layer and organic structure-directing agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional zeolite membranes are used for CO2 separation, then CO2/N2 and CO2/CH4 separation can be achieved under dry conditions, but separation performance deteriorates under wet conditions due to moisture interference
Solution Approach 1:
The patent changes the chemical composition parameters of the zeolite membrane by controlling the Si/Al ratio in the synthetic precursor to be 5 or more. This parameter change modifies the membrane's hydrophobicity and defect formation characteristics, enabling it to maintain high CO2 separation performance under wet conditions where conventional membranes fail
Solution Approach 2:
The patent creates local quality differences within the zeolite structure by controlling the distribution of Si and Al atoms. The synthetic precursor with controlled Si/Al ratio produces zeolite with specific local chemical environments that resist moisture adsorption while maintaining CO2 permeability, addressing the moisture interference problem at the molecular level
2Reliability
If dehydration processes are implemented to remove moisture from feed gas, then membrane separation performance is improved, but process cost increases
Solution Approach 1:
The patent extracts the harmful moisture component from the system by designing a membrane that inherently repels water. The hydrophobic zeolite membrane with Si/Al ratio of 5 or more prevents moisture from entering the membrane structure, eliminating the need for separate dehydration process steps and reducing overall process cost
Solution Approach 2:
The patent converts the harmful effect of moisture into a beneficial feature by utilizing the hydrophobic nature of the modified zeolite. The moisture that would normally hinder separation is now excluded by the membrane's inherent water-repelling properties, allowing direct use of wet feed gas without additional processing
3Reliability
If zeolite surface is made hydrophobic to resist moisture, then CO2 permeance is maintained under wet conditions, but manufacturing precision requirements increase
Solution Approach 1:
The patent simplifies the control of hydrophobicity by changing the fundamental Si/Al ratio parameter in the synthetic precursor to 5 or more. This single parameter change simultaneously achieves the desired hydrophobicity and controls defect formation, reducing the complexity of manufacturing precision requirements compared to surface modification methods
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 membrane achieves enhanced CO2/N2 and CO2/CH4 separation performance under both dry and wet conditions, maintaining high separation capacity regardless of temperature or pressure, with improved economic efficiency by minimizing the need for dehydration processes.
Implementation Method 1
In the zeolite membrane, permeation is achieved by adsorption, diffusion and desorption. The intrinsic pore structure and surface properties of the zeolite have an influence on this process.
Implementation Method 2
In the zeolite membrane, permeation is achieved by adsorption, diffusion and desorption.
Implementation Method 3
when the ratio of Al in the structure is lowered, the surface becomes hydrophobic. The hydrophobic surface has been reported to be less susceptible to moisture and thus result in higher permeance.
Implementation Method 4
CHA zeolites with a pore size of 0.37×0.42 nm2 have a structure suitable for separating CO2 having a size of 0.33 nm from N2 (0.364 nm) and CH4 (0.38 nm).
Data Source
AI summary
Disclosed are a CHA zeolite membrane and a method of preparing the same, and more particularly, a CHA zeolite membrane having high capacity to separate CO2/N2 and CO2/CH4 even under wet conditions using a membrane produced using a synthetic precursor having a controlled ratio of Si and Al, a method of preparing the same, and a method of capturing and removing carbon dioxide using the membrane.