Active Metal M-CHA/M-MOR Composite Molecular Sieve Preparation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for preparing active metal-containing M-CHA/M-MOR composite molecular sieves are complex, energy-intensive, and generate significant wastewater, limiting their industrial scalability and application in waste gas treatment.
Innovation Solution
A direct preparation method involving a hydrothermal reaction with a crystal form modifier containing molecular sieve secondary structural units, which induces the formation of an intergrowth structure with a two-stage reaction process, reducing process complexity and energy consumption while achieving high SCR catalytic activity and hydrothermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional multi-step preparation methods are used to introduce active metal into molecular sieve, then active metal-containing molecular sieve can be obtained, but the process becomes complicated and energy consumption increases
Solution Approach 1:
The active metal complex is introduced into the gel system before the hydrothermal reaction begins, allowing the active metal to be incorporated into the molecular sieve structure during the crystal formation process rather than requiring subsequent separate introduction steps. This preliminary incorporation simplifies the overall process flow while ensuring reliable active metal content.
2Reliability
If conventional preparation methods with multiple washing and separation steps are used, then active metal-containing molecular sieve can be obtained, but wastewater production amount increases
Solution Approach 1:
The introduction of active metal complex, crystallization, and formation of molecular sieve structure are merged into a single hydrothermal reaction process. This integration eliminates the need for separate washing and separation steps that would otherwise be required, thereby reducing wastewater production while maintaining reliable active metal content in the final product.
3Reliability
If conventional preparation methods with multiple calcination steps are used, then active metal-containing molecular sieve can be obtained, but energy consumption increases
Solution Approach 1:
The active metal complex is incorporated into the gel system before the hydrothermal reaction, allowing the molecular sieve structure to form with the active metal already positioned within the framework. This eliminates the need for subsequent separate calcination steps to introduce and activate the metal, reducing overall energy consumption while ensuring reliable active metal content.
4Reliability
If M-CHA molecular sieve is used, then excellent SCR catalytic activity is achieved, but hydrothermal stability and resistance to N2O formation are insufficient
Solution Approach 1:
The patent creates a composite molecular sieve structure that combines the catalytically active CHA framework with the hydrothermally stable MOR framework. This composite structure allows the material to exhibit both excellent SCR catalytic activity from the CHA component and improved hydrothermal stability from the MOR component, resolving the contradiction between catalytic performance and structural stability.
5Stability of the object's composition
If M-MOR molecular sieve is used, then excellent hydrothermal stability is achieved, but SCR catalytic activity temperature window is narrow
Solution Approach 1:
The patent creates a composite molecular sieve structure that combines the hydrothermally stable MOR framework with the catalytically active CHA framework. This composite structure allows the material to exhibit both excellent hydrothermal stability from the MOR component and broad SCR catalytic activity temperature window from the CHA component, resolving the contradiction between structural stability and catalytic 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 method produces active metal-containing M-CHA/M-MOR composite molecular sieves with enhanced SCR catalytic activity, hydrothermal stability, and resistance to N2O formation, suitable for wider industrial applications with reduced waste and energy usage.
Implementation Method 1
S2, subjecting the gel to a hydrothermal reaction, and after the reaction is finished, separating the resulting slurry to obtain a composite molecular sieve
Implementation Method 2
performing active metal M ion exchange to obtain an active metal M-containing molecular sieve
Implementation Method 3
Molecular sieves are important adsorption/catalytic materials
Data Source
AI summary
The present disclosure provides an active metal-containing M-CHA/M-MOR composite molecular sieve and a preparation method. The preparation method includes: S1, adding an alkali source, a silicon source, an aluminum source, a structure-directing agent, an active metal complex and a crystal form modifier into water, and performing stirring to obtain a gel, wherein the crystal form modifier is an aqueous solution containing a molecular sieve secondary structural unit prepared based on at least one of an MOR molecular sieve, a CHA/MOR composite molecular sieve, and a CHA-MOR mixed molecular sieve; S2, subjecting the gel to a hydrothermal reaction, and separating the resulting slurry to obtain a composite molecular sieve; and S3, drying the composite molecular sieve, and performing calcining to obtain the active metal-containing M-CHA/M-MOR composite molecular sieve. The direct preparation method has the advantages of short process flow, low wastewater production, low energy consumption and the like.