Chabazite Zeolite Membrane Pore Control via CVD
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Solution Overview
Problem
Existing zeolite membranes struggle with efficient CO2/N2 separation, especially in the presence of water, due to defects and hydrophilic properties, which reduce CO2 adsorption and separation performance at high temperatures.
Innovation Solution
A chabazite zeolite membrane with controlled pore size is produced using chemical vapor deposition to reduce defects and optimize pore size, allowing for enhanced CO2/N2 separation performance under both dry and moist conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If hydrophilic zeolite structures are used to achieve CO2 adsorption, then CO2 adsorption capacity is improved, but CO2/N2 separation performance deteriorates at high temperatures due to reduced interaction between CO2 and zeolite structures
Solution Approach 1:
The patent changes the thermal stability parameter of the zeolite structure by using silica-rich composition with high Si/Al ratio, allowing the membrane to maintain its hydrophobic properties and CO2 adsorption capacity at high temperatures up to 200°C, resolving the contradiction between CO2 adsorption and high-temperature separation performance
Solution Approach 2:
The patent creates a composite structure by combining silica-rich zeolite framework with controlled pore size, achieving both hydrophobicity for high-temperature stability and appropriate CO2 adsorption capacity, thus improving CO2/N2 separation performance while maintaining CO2 adsorption
2Reliability
If pore size is reduced to improve CO2/N2 separation, then separation factor is improved, but permeance deteriorates
Solution Approach 1:
The patent applies local quality modification by selectively depositing silica material specifically at the pore mouths and internal pore surfaces of the chabazite zeolite membrane, rather than uniformly throughout the structure. This localized deposition reduces pore size at critical separation interfaces while maintaining overall permeability pathways, achieving both high separation factor and acceptable permeance
3Strength
If defects are present in the zeolite membrane to maintain structural integrity, then mechanical strength is improved, but CO2/N2 separation performance deteriorates due to reduced separation efficiency
Solution Approach 1:
The patent extracts and removes defects from the zeolite membrane structure through a controlled chemical vapor deposition process that fills vacancies and imperfections in the silica-rich chabazite framework, creating a more homogeneous structure with improved CO2/N2 separation performance while maintaining mechanical integrity
Solution Approach 2:
The patent performs preliminary defect treatment by subjecting the zeolite membrane to chemical vapor deposition before actual CO2 separation operations, pre-conditioning the membrane structure to eliminate defects that would compromise separation efficiency, thus ensuring optimal performance from the start
4Object-affected harmful factors
If all-silica constituents are used to minimize H2O flux, then hydrophobicity is improved, but CO2 adsorption capacity deteriorates due to reduced interaction with CO2
Solution Approach 1:
The patent optimizes the silica composition parameter by controlling the Si/Al ratio in the chabazite framework, achieving a balance where the structure remains sufficiently hydrophobic to reject water while maintaining appropriate silica content for CO2 adsorption interaction, thus resolving the contradiction between hydrophobicity and CO2 adsorption capacity
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 method achieves a significant increase in CO2/N2 separation factor and permeance, maintaining effective carbon dioxide capture from nitrogen even in wet conditions, with a CO2/N2 separation factor up to 8.8, surpassing conventional membranes.
Implementation Method 1
treating chemical vapor deposition (CVD) on the chabazite zeolite membrane while introducing silica precursor having a vapor-phase onto surface of the chabazite zeolite membrane
Implementation Method 2
The rigid molecular-sized pore structures in zeolites make them appropriate for separating gas molecules via the recognition of the minute difference in their shapes and/or sizes
Data Source
AI summary
The present invention relates to a chabazite zeolite membrane with a controlled pore size and a production method thereof, wherein the sizes of pore space and pore mouth of the chabazite zeolite membrane are finely controlled through chemical vapor deposition. Through the chemical vapor deposition, defects present in the chabazite zeolite membrane are eliminated, and the pore size is effectively controlled. Thus, unlike hydrophilic membranes showing excellent CO2/N2 separation performance under a dry condition, the chabazite zeolite membrane with a controlled pore size according to the present invention has a hydrophobic surface, and thus can maintain excellent CO2/N2 separation performance even under a wet condition. Accordingly, the chabazite zeolite membrane of the present invention can effectively capture carbon dioxide from nitrogen under various environmental conditions.