AEI Zeolite Hydrothermal Pretreatment for Faster Crystallization
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Solution Overview
Problem
Existing AEI zeolite production methods that do not use crystalline aluminosilicate as a starting material require long crystallization times and achieve low yields, making them unsuitable for industrial applications.
Innovation Solution
A production method involving hydrothermal processing of an amorphous composition containing amorphous silica, alumina, alkali, and water, followed by crystallization with an organic structure-directing agent, to efficiently produce AEI zeolite with a suitable silica-to-alumina ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If amorphous compounds are used as starting materials other than Y zeolite, then production cost is reduced, but crystallization time increases and yield decreases
Solution Approach 1:
The patent applies preliminary action by conducting hydrothermal treatment of the amorphous composition before crystallization. This pre-treatment step modifies the amorphous material to create a more favorable state for subsequent crystallization, enabling faster crystal growth and higher yield while maintaining the cost advantage of using non-Y zeolite starting materials.
Solution Approach 2:
The patent employs parameter changes by optimizing the composition ratios of silica, alumina, and alkali components in the amorphous starting material. By adjusting these chemical parameters within specific ranges, the crystallization kinetics are enhanced, achieving both cost reduction and improved crystallization efficiency simultaneously.
2Ease of manufacture
If amorphous compounds are used as starting materials other than Y zeolite, then production cost is reduced, but crystallization time increases
Solution Approach 1:
The hydrothermal treatment step performed before crystallization serves as a preliminary action that prepares the amorphous composition for faster crystal formation. This pre-treatment reduces the activation energy required for nucleation and growth, thereby shortening the overall crystallization time while maintaining the use of cost-effective amorphous starting materials.
Solution Approach 2:
The patent introduces an intermediary hydrothermal treatment step that acts as a bridge between the amorphous starting material and the crystallization process. This intermediary step transforms the amorphous structure into a more crystalline-ready state, facilitating faster subsequent crystallization without requiring expensive Y zeolite as the starting material.
3Ease of manufacture
If typical AEI zeolite production methods without crystalline aluminosilicate are used, then Y zeolite cost is avoided, but yield is low
Solution Approach 1:
The patent optimizes the compositional parameters of the amorphous starting material, specifically controlling the SiO2/Al2O3 ratio and alkali content within defined ranges. These parameter adjustments create optimal conditions for high-yield AEI zeolite formation from inexpensive amorphous precursors, eliminating the need for costly Y zeolite while maximizing product yield.
Solution Approach 2:
The pre-crystallization hydrothermal treatment serves as a preliminary action that enhances the reactivity and crystallizability of the amorphous starting material. This treatment increases the yield of AEI zeolite by preparing the amorphous composition to more efficiently convert into crystalline product during the subsequent crystallization step.
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 achieves a shorter crystallization time and higher yield, producing AEI zeolite suitable as a nitrogen oxide-reducing catalyst or support, thus being industrially applicable.
Implementation Method 1
a step of hydrothermally processing an amorphous composition containing an amorphous silica source, an amorphous alumina source, an alkali source and water
Implementation Method 2
crystallizing a raw material composition obtained by mixing an organic structure-directing agent and the amorphous composition
Data Source
AI summary
Provided is at least one of a production method that can obtain AEI zeolite that has a silica-to-alumina molar ratio suitable as a nitrogen oxide-reducing catalyst or a support thereof and that involves a shorter crystallization time and higher yield compared to a typical AEI zeolite production method that does not use crystalline aluminosilicate as a starting material, or an AEI zeolite production method that is expected to be industrially applicable. An AEI zeolite production method includes hydrothermally processing an amorphous composition containing an amorphous silica source, an amorphous alumina source, an alkali source and water, and then crystallizing a raw material composition obtained by mixing an organic structure-directing agent and the amorphous composition.