Zeolite Membrane Operation for Crack-Free Adsorption Separation
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Solution Overview
Problem
Existing membrane separation methods, such as those using LTA-type zeolite membranes, are prone to breakage during temperature changes due to uneven adsorptive substance concentration distribution, leading to cracks in the separation membrane.
Innovation Solution
An operating method for a separation device that controls the adsorptive substance concentration distribution within a specific range (0 to 0.3) and adjusts the average Reynolds number of the mixture to 2,000 or more, using a zeolite membrane with a SiO2/Al2O3 molar ratio less than 5, to stabilize the membrane during temperature and pressure changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the temperature of the LTA-type zeolite membrane is increased to an adsorption temperature or decreased from the adsorption temperature to room temperature, then the adsorption separation function is improved, but the membrane may break due to thermal stress
Solution Approach 1:
The patent applies parameter changes by controlling the concentration distribution of adsorptive substance (water) in the mixture to be equal to or less than 0.3. This parameter control prevents uneven adsorption-induced stress on the zeolite membrane during temperature changes, allowing the membrane to maintain its strength while operating at adsorption temperatures. The method transforms the problem from managing thermal stress directly to managing concentration distribution, which indirectly protects the membrane.
2Quantity of substance
If the concentration distribution of adsorptive substance in the mixture is high, then the adsorption capacity is improved, but uneven volume expansion and contraction of the membrane occurs leading to breakage
Solution Approach 1:
The patent uses parameter changes by setting a specific threshold (0.3) for the concentration distribution of adsorptive substance. By controlling this parameter, the patent achieves a balance where sufficient adsorption capacity is maintained while preventing the concentration gradients that cause uneven volume expansion and contraction. This parameter control ensures the membrane composition remains uniform during operation.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the concentration distribution of adsorptive substance in the mixture and adjusting operating conditions to maintain it at or below 0.3. This feedback mechanism ensures that the membrane is always operated within safe concentration limits, preventing the development of uneven stress patterns that would lead to breakage while still achieving effective separation.
3Stress or pressure
If the Reynolds number of the mixture is low, then the pressure drop is reduced, but the adsorption efficiency decreases due to insufficient mass transfer
Solution Approach 1:
The patent applies parameter changes by adjusting the Reynolds number of the mixture to 2,000 or more. This parameter adjustment optimizes the flow regime to enhance mass transfer and adsorption efficiency. By controlling the Reynolds number, the patent achieves sufficient turbulence to improve mass transfer to the membrane surface while managing the pressure drop through system design and operating conditions.
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 effectively suppresses membrane breakage by ensuring uniform volume expansion and contraction, allowing stable adsorption and separation of substances without cracking.
Implementation Method 1
a mixture heated to a predetermined adsorption temperature is supplied to the LTA-type zeolite membrane to allow a specific substance to be adsorbed to the LTA-type zeolite membrane and separated from the mixture
Implementation Method 2
the breakage of the LTA-type zeolite membrane, for example, a crack may occur in a step of separating the specific substance, in particular, in a step of increasing the temperature of the LTA-type zeolite membrane to an adsorption temperature and a step of decreasing the temperature of the LTA-type zeolite membrane from the adsorption temperature to room temperature
Data Source
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AI summary
Provided is an operating method for a separation device, which enables suppression of breakage of a separation membrane. The operating method for a separation device according to an embodiment of the present disclosure is an operating method for a separation device including a separation membrane, the separation device including: a first flow path to which a mixture containing an adsorptive substance to be adsorbed to the separation membrane is to be supplied; and a second flow path through which a substance that has permeated through the separation membrane is allowed to flow. The operating method for a separation device includes a step of supplying the mixture to the first flow path so that an adsorptive substance concentration distribution in a direction of passage of the mixture becomes larger than 0 and equal to or less than 0.3.