Zeolite Catalyst Synthesis via Vapor-Phase Crystallization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current synthesis techniques for crystalline zeolite catalysts face challenges such as difficulty in achieving uniformity and reproducibility, leading to complicated and expensive large-scale production, with resulting products having low crush strength and poor quality due to issues like non-uniform crystallization conditions and the presence of excess alkali metal hydroxide.
Innovation Solution
A method involving the crystallization of a pre-formed extrudate mixture with controlled alkali metal hydroxide levels, using a support to separate excess alkali metal hydroxide and maintain uniformity, which enhances vapor phase conditions and promotes the formation of high-quality zeolite catalysts with improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional liquid-phase hydrothermal treatment is used for zeolite synthesis, then crystalline zeolite can be produced, but the process suffers from non-uniform crystallization conditions, low crush strength, and poor quality
Solution Approach 1:
The patent replaces the conventional liquid-phase hydrothermal treatment with vapor-phase transport method. This substitution transforms the synthesis environment from liquid to vapor phase, enabling more uniform crystallization conditions and producing zeolite with higher crush strength and improved quality.
2Manufacturing precision
If vapor phase transport method is used, then uniformity and quality improve, but the process becomes more complicated and time-consuming
Solution Approach 1:
The patent employs pre-formed extrudate as starting material, which has already been prepared with controlled composition and structure. This preliminary preparation step simplifies the subsequent vapor-phase crystallization process by providing a uniform substrate, thereby reducing overall process complexity while maintaining high uniformity and quality.
3Productivity
If excess alkali metal hydroxide is present during crystallization, then the crystallization process can proceed, but the product quality deteriorates due to non-uniformity and low crush strength
Solution Approach 1:
The patent removes excess alkali metal hydroxide from the system during the crystallization process. By extracting this harmful excess component, the method prevents the formation of non-uniform products and achieves high uniformity and crush strength while maintaining adequate crystallization rate.
4Productivity
If large-scale production is attempted using conventional methods, then production volume increases, but cost and complexity increase due to difficulty in achieving uniformity and reproducibility
Solution Approach 1:
The patent changes the fundamental parameters of the synthesis process by using vapor-phase transport instead of liquid-phase hydrothermal treatment. This parameter change enables large-scale production with improved uniformity and reproducibility, thereby reducing complexity and cost while increasing production volume.
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 results in zeolite catalysts with higher surface area, crush strength, and uniformity, overcoming the limitations of conventional processes by producing catalysts with enhanced mechanical properties and quality.
Implementation Method 1
crystallizing a pre-formed extrudate mixture with controlled alkali metal hydroxide levels
Implementation Method 2
enhances vapor phase conditions and promotes the formation of high-quality zeolite catalysts
Data Source
AI summary
The invention relates to a process for converting hydrocarbons with a catalyst comprising a crystalline molecular sieve composition which is obtainable by crystallizing a pre-formed extrudate mixture in a reactor and, during crystallization, removing excess alkali metal hydroxide from the pre-formed extrudate. The pre-formed extrudate mixture comprises at least one source of ions of tetravalent element Y, at least one source of alkali metal hydroxide, water, optionally at least one seed crystal, and optionally at least one source of ions of trivalent element X. The reaction mixture has the following mole composition: Y:X2=10 to infinity; OH−:Y=0.001 to 2; and M+:Y=0.001 to 2; wherein M is an alkali metal. The amount of water in the mixture is at least sufficient to permit extrusion of said reaction mixture.