Zeolite Membrane Gas Separation With Trace Gas Adsorption Control
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Solution Overview
Problem
Existing gas separation methods using zeolite membranes face issues with time-varying reductions in permeability due to minor components in exhaust gases, leading to the need for complex pretreatment facilities to remove these components.
Innovation Solution
A gas separation method utilizing a zeolite membrane complex with a porous support, where a mixed gas containing a high permeability gas and a trace gas is supplied, with the trace gas having a higher molar concentration and specific adsorption equilibrium constants relative to the high permeability gas, to maintain permeability and reduce adsorption on the membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a zeolite membrane is used to separate carbon dioxide from exhaust gas, then carbon dioxide can be separated and collected, but the selectivity of the membrane decreases over time due to adsorption of minor components on small pores
Solution Approach 1:
The invention segments the trace gas components into two categories based on their adsorption equilibrium constants: a first gas with lower adsorption affinity (K1 < 60×Kh) and a second gas with higher adsorption affinity (K2 ≥ 400×Kh). This segmentation allows selective management of different components - the first gas can be present at higher concentrations without harming membrane performance, while the second gas is controlled at low concentrations to prevent pore blockage and selectivity degradation over time.
Solution Approach 2:
The invention establishes specific parameter thresholds for gas composition and adsorption equilibrium constants. By defining that the first gas concentration should be higher than the second gas concentration, and by setting the adsorption equilibrium constant ratios (K1/Kh < 60 and K2/Kh ≥ 400), the system optimizes the balance between maintaining high permeability and preventing selectivity loss during prolonged operation.
2Reliability
If pretreatment facilities are added to remove all minor substances from exhaust gas, then membrane performance can be maintained, but the facility becomes complicated and larger in size
Solution Approach 1:
The invention extracts only the critical control parameter - the concentration relationship between the first gas (lower adsorption affinity) and the second gas (higher adsorption affinity). Instead of removing all minor components through complex pretreatment, the system identifies that maintaining a specific concentration ratio of these two gas types is sufficient to protect membrane performance, thereby simplifying the pretreatment requirement.
Solution Approach 2:
The invention creates a universal criterion that applies to various exhaust gas compositions from different sources (olefin production plants, synthetic alcohol plants, ester plants, etc.). By focusing on the adsorption equilibrium constant ratios and concentration relationships rather than specific gas types, the same control strategy can be universally applied across different industrial applications without requiring custom-designed complex pretreatment facilities for each case.
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 approach effectively suppresses time-varying reductions in permeability, simplifying the pretreatment process and maintaining membrane performance by selectively adsorbing and separating gases based on their adsorption equilibrium constants.
Implementation Method 1
an adsorption equilibrium constant of the first gas on the zeolite membrane being less than 60 times an adsorption equilibrium constant of the high permeability gas on the zeolite membrane, and an adsorption equilibrium constant of the second gas on the zeolite membrane being 400 times or more the adsorption equilibrium constant of the high permeability gas in the zeolite membrane
Data Source
AI summary
A gas separation method includes supplying a mixed gas to a zeolite membrane complex and permeating a high permeability gas through the zeolite membrane complex to separate the high permeability gas from other gases. The mixed gas includes a high permeability gas and a trace gas that is lower in concentration than the high permeability gas. The molar concentration of a first gas included in the trace gas in the mixed gas is higher than the molar concentration of a second gas included in the trace gas in the mixed gas. The adsorption equilibrium constant of the first gas on the zeolite membrane is less than 60 times that of the high permeability gas. The adsorption equilibrium constant of the second gas on the zeolite membrane is 400 times or more that of the high permeability gas.