Carbon Molecular Sieve Monoliths for Low-Pressure-Drop Gas Separation
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Solution Overview
Problem
Existing gas separation technologies using carbon molecular sieves (CMS) face challenges with pressure drop and mass transfer issues in conventional adsorbent beds, necessitating the development of structured adsorbents that reduce bed size and capital costs.
Innovation Solution
A method for forming carbon molecular sieve monoliths by loading polymer fibers into a mold, heating to form a polymer monolith, and pyrolyzing at specific temperatures to create aligned fibers with high cell density and channels, resulting in a carbon molecular sieve monolith with enhanced separation capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional packed beds or columns are used for gas separation, then gas separation can be achieved, but pressure drop and mass transfer issues occur
Solution Approach 1:
The patent employs carbon molecular sieve monoliths with controlled microporous structures to achieve gas separation. The porous monolith structure provides high surface area and selective adsorption sites while maintaining open channels for gas flow, thereby achieving separation efficiency without the pressure drop associated with conventional packed beds
Solution Approach 2:
The invention uses composite carbon molecular sieve materials with specific micropore size distributions and surface properties tailored for different gas separation applications. These composite structures combine the advantages of high adsorption capacity with low flow resistance, resolving the contradiction between separation efficiency and pressure drop
2Reliability
If conventional packed beds are used for gas separation, then gas separation can be achieved, but mass transfer issues occur
Solution Approach 1:
The carbon molecular sieve monoliths feature hierarchical porous structures with micropores for selective adsorption and meso/macropores for rapid mass transfer. This dual-scale porosity enables both high separation efficiency and improved mass transfer rates by providing multiple pathways for gas molecules to reach active sites
Solution Approach 2:
The monolith structure transitions from conventional one-dimensional packed bed flow to three-dimensional interconnected channel networks. This dimensional change provides multiple parallel pathways for gas flow, reducing mass transfer resistance and improving overall separation performance
3Reliability
If conventional adsorbent beds are used, then gas separation is achieved, but larger bed size and higher capital cost are required
Solution Approach 1:
The high porosity and surface area of carbon molecular sieve monoliths provide extensive adsorption capacity within a compact volume. The structured monolith format with controlled pore architecture maximizes the utilization of adsorbent material, achieving high separation capability in smaller bed sizes compared to conventional packed beds
Solution Approach 2:
The engineered composite carbon molecular sieve structures with optimized micropore size distributions and surface chemistries provide enhanced separation performance per unit volume, allowing for more compact adsorbent beds that reduce both equipment size and capital costs
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 carbon molecular sieve monoliths achieve efficient gas separation with low pressure drop and high separation efficiency, enabling shorter cycle operations and reduced capital costs.
Implementation Method 1
heating the mold containing the polymer fibers to a temperature in a range from 50° C. to 350° C. to form a polymer monolith
Implementation Method 2
pyrolizing the polymer monolith by heating the polymer monolith to a temperature in a range from 500° C. to 1700° C.
Implementation Method 3
the micropore size determines which gas in a gas mixture is adsorbed and which is not
Data Source
AI summary
Methods for forming a carbon molecular sieve includes loading polymer fibers into a mold and heating the mold containing the polymer fibers to a temperature in a range from 50° C. to 350° C. to form a polymer monolith. The polymer monolith is then pyrolized by heating to a temperature in a range from 500° C. to 1700° C. A carbon molecular sieve monolith includes a first end and a second end opposite the first end, and carbon molecular sieve fibers aligned in parallel from the first end of the carbon molecular sieve monolith to the second end of the carbon molecular sieve monolith. Channels extend from the first end of the carbon molecular sieve monolith to the second end of the carbon molecular sieve monolith, and outer surfaces of the carbon molecular sieve fibers are joined. The carbon molecular sieve monolith has a cell density of greater than 500 cells per square inch.