Low-Acidity Clay Binder for High-Strength Zeolite Moldings
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Solution Overview
Problem
Existing methods for producing high-strength zeolite moldings for adsorptive separation are complex and costly, often resulting in moldings with lower strength that can lead to equipment malfunctions due to powdering, and existing binders can degrade adsorptive separation performance.
Innovation Solution
A high-strength zeolite molding using a low-acidity clay binder, produced by adding clay, a molding aid, a water-soluble sodium salt, and water to zeolite, followed by kneading, drying, and firing at specific temperatures to achieve a compressive strength of 20 N or more, while maintaining low acidity to prevent side reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a binder is used to increase the strength of zeolite molding, then the compressive strength is improved, but the adsorptive separation performance is degraded due to side reactions caused by acid sites in the binder
Solution Approach 1:
The invention changes the chemical parameter of the binder by selecting clay with low acid site density (solid acidity of 0.10 mmol/g or less). This parameter change allows the binder to provide mechanical strength without causing harmful side reactions with aromatic hydrocarbons, thus resolving the contradiction between strength improvement and performance degradation
Solution Approach 2:
The invention uses clay as a binder that can be easily removed or deactivated after serving its purpose of providing green body strength during molding. The clay binder fulfills its temporary role of enabling molding operations and then can be eliminated through heat treatment or other processing, leaving no harmful residues that would affect long-term adsorptive separation performance
2Strength
If existing binder materials are used to create zeolite molding, then the molding strength is improved, but the production process becomes more complex and costly
Solution Approach 1:
The invention extracts and eliminates the complex multi-step conversion processes described in prior art (such as converting kaolin to meta-kaolin, then to zeolite through hydrothermal treatment). Instead, it directly uses low-acidity clay as a functional binder that provides necessary strength without requiring elaborate conversion steps, thereby simplifying the production process while maintaining molding strength
Solution Approach 2:
The clay binder serves multiple functions simultaneously: it provides mechanical strength for molding, acts as a plasticizer for shaping, and can be removed without affecting the final zeolite product. This multi-functionality eliminates the need for separate binder addition and removal steps, reducing production complexity
3Reliability
If binderless zeolite molding is produced to maintain adsorptive separation performance, then the purity is improved, but the strength is reduced leading to powdering and equipment malfunction
Solution Approach 1:
The invention introduces low-acidity clay as an intermediary substance that temporarily provides mechanical strength during molding and handling. This intermediary binder does not interfere with the adsorptive separation function of the zeolite and can be removed or deactivated afterward, allowing the production of strong moldings that maintain high adsorptive separation performance
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 resulting high-strength zeolite molding exhibits improved compressive strength and reduced reactivity, minimizing powdering and equipment malfunctions, and maintaining effective adsorptive separation performance without degrading the adsorbate.
Implementation Method 1
a high-strength zeolite molding comprising 10 parts by weight or more and 40 parts by weight or less of clay relative to 100 parts by weight of zeolite, and having a compressive strength of 20 N or more
Implementation Method 2
a water adsorption amount of 10 (g/100 g) or less under conditions of 25° C. and a relative pressure of 0.5
Implementation Method 3
when clay or alumina having an acid site is used as the binder to separate an aromatic hydrocarbon by adsorption, the aromatic hydrocarbon reacts
Data Source
AI summary
A high-strength zeolite molding includes 10 parts by weight or more and 40 parts by weight or less of clay relative to 100 parts by weight of zeolite, and having a compressive strength of 20 N or more, in which the zeolite contains at least one zeolite that has Si/Al2 of 300 or more and 100000 or less and a water adsorption amount of 10 (g/100 g) or less under conditions of 25° C. and a relative pressure of 0.5, and the clay contains at least one clay that has a solid acidity of 0.15 mmol/g or less as determined by a NH3-TPD method. A method for producing includes kneading, molding, drying and disintegrating a product and then firing at 400° C. or higher and 700° C. or lower.