Zeolite Membrane Seed Layer Thermal Stress Reduction
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Solution Overview
Problem
Existing zeolite membrane manufacturing methods often result in defects such as cracks and zeolite powder detachment during thermal treatment, which deteriorate gas separation performance and make substrate processing difficult, especially due to differences in thermal expansion coefficients and mechanical strength.
Innovation Solution
A ceramic porous substrate with a seed crystal-containing layer is developed, where a zeolite powder and ceramic powder mixture is fired onto the substrate, reducing zeolite powder detachment and allowing for pre-treatment processes like air-spraying and washing, and the ceramic powder helps in reducing thermal stress by matching thermal expansion coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If zeolite powder is allowed to adhere to a porous substrate, then a zeolite membrane can be formed, but the zeolite powder easily falls off and defects such as cracks are generated
Solution Approach 1:
The patent introduces a specific binder as an intermediary substance between the zeolite powder and the porous substrate. This binder mediates the adhesion process, providing strong bonding while accommodating thermal expansion differences, thereby preventing both powder detachment and crack formation during thermal treatment and gas separation operations.
2Reliability
If zeolite powder is adhered to the substrate, then gas separation function is achieved, but processing and air-spraying for removing foreign substances become impossible
Solution Approach 1:
The patent applies preliminary action by using a binder with controlled adhesion characteristics that allows substrate processing and air-spraying to be performed before the zeolite membrane formation becomes irreversible. This enables foreign substance removal and surface treatment to be completed while maintaining the ability to form the functional zeolite membrane subsequently.
3Ease of manufacture
If thermal treatment is conducted to burn out structure-determining agent, then zeolite membrane is completed, but cracks are generated due to thermal expansion difference
Solution Approach 1:
The patent applies parameter changes by carefully controlling the binder's adhesion strength and thermal properties to match the thermal expansion characteristics of the zeolite and substrate. This parameter optimization allows thermal treatment to proceed successfully for completing the zeolite membrane while preventing crack formation through reduced thermal stress.
4Productivity
If zeolite powder is used as seed crystal, then hydrothermal synthesis can proceed, but careful handling is necessary to prevent powder fall-off
Solution Approach 1:
The binder serves as a mediator that secures the zeolite powder in place during handling and hydrothermal synthesis operations. This intermediary substance eliminates the need for careful manual handling while maintaining the zeolite powder's functionality as seed crystals for efficient hydrothermal synthesis.
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 solution prevents defects like cracks in the zeolite layer, enhances membrane strength, and allows for easy handling and processing of the substrate before hydrothermal synthesis, resulting in improved gas separation performance and mechanical stability of the zeolite membrane.
Implementation Method 1
differences in thermal expansion coefficients and mechanical strength
Implementation Method 2
grow a zeolite powder (seed crystal) to form a zeolite membrane
Implementation Method 3
a zeolite membrane of a DDR (Deca-Dodecasil 3R) type zeolite... containing oxygen 8-membered ring, and having relatively small pores (pore size of 4.4×3.6 angstrom) among various kinds of zeolite in the crystal structure is used as a separation membrane to allow only carbon dioxide (CO2) gas or the like to selectively permeate the membrane
Data Source
AI summary
A porous substrate with a seed crystal-containing layer for manufacturing a zeolite membrane includes: a ceramic porous substrate, and a seed crystal-containing layer containing a zeolite powder to function as a seed crystal for forming a zeolite membrane and a ceramic powder and being loaded on a surface of the ceramic porous substrate and fired to fix the seed crystal-containing layer on the porous substrate. The porous substrate with a seed crystal-containing layer used for manufacturing a zeolite membrane inhibits a defect such as a crack from being generated in the zeolite layer upon manufacture or use by manufacturing a zeolite membrane by the use of the substrate which then can be subjected to air-spraying, washing, and processing for the purpose of removing a foreign substance, etc., prior to hydrothermal synthesis.