Low-Sodium Zeolite Catalyst for Olefin Conversion
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Solution Overview
Problem
Current processes for converting oxygenates to olefins face challenges in achieving high selectivity and catalyst efficiency, particularly in the production of short-chain hydrocarbons, where zeolitic materials with MFI, MEL, and MWW frameworks require optimization to improve conversion efficiency and catalyst longevity.
Innovation Solution
A process using zeolitic materials with MFI, MEL, and MWW frameworks synthesized under alkali-free conditions, with a sodium content of 3 wt.% or less, to enhance the conversion of oxygenates to olefins, resulting in improved selectivity and sustained catalyst activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional zeolitic materials with MFI, MEL, and MWW frameworks are used for converting oxygenates to olefins, then catalytic activity is achieved, but selectivity and catalyst efficiency are insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the sodium content in the zeolitic material to 3 wt.% or less, and by optimizing the synthesis conditions (temperature, time, precursor ratios) to achieve the desired MFI, MEL, and MWW framework structures. This systematic parameter optimization resolves the contradiction by enhancing both selectivity and conversion efficiency simultaneously through controlled material composition and structure.
Solution Approach 2:
The patent employs composite zeolitic materials combining multiple framework types (MFI, MEL, MWW) within a single catalyst system. This composite approach allows the catalyst to exhibit synergistic effects, where different framework structures contribute differently to catalytic activity and selectivity, thereby resolving the contradiction between reliability and productivity.
2Reliability
If alkali-based synthesis methods are used for zeolitic materials, then catalyst activity is enhanced, but production costs and process complexity increase
Solution Approach 1:
The patent extracts and eliminates the need for alkali-based synthesis methods by employing acid-based synthesis procedures. This extraction of the harmful/complex element (alkali) from the synthesis process reduces production costs and simplifies manufacturing while maintaining catalyst activity through alternative acid-catalyzed formation mechanisms.
Solution Approach 2:
The patent adopts cost-effective, readily available acid-based reagents and synthesis conditions that are more economical than alkali-based methods. By using inexpensive acid catalysts and simpler processing steps, the manufacturing cost is reduced while achieving comparable or superior catalyst performance.
3Manufacturing precision
If ion-exchange procedures are performed after zeolite crystallization, then H-form zeolite is obtained, but manufacturing time and energy consumption increase
Solution Approach 1:
The patent performs preliminary action by directly synthesizing the H-form zeolite during the crystallization process itself, rather than requiring subsequent ion-exchange steps. The acid-based synthesis method directly forms the protonated framework structure, eliminating the need for time-consuming post-synthesis ion-exchange procedures and reducing overall manufacturing time.
Solution Approach 2:
The patent extracts and removes the ion-exchange step from the manufacturing process by incorporating the framework formation and protonation into a single crystallization operation. This extraction of the separate ion-exchange procedure eliminates the associated time and energy consumption while maintaining the desired H-form zeolite structure.
4Stability of the object's composition
If high sodium content zeolitic materials are used, then catalyst stability is improved, but selectivity towards desired olefin products decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the sodium content to a maximum of 3 wt.% and optimizing the acid-base balance in the zeolitic material. This controlled parameter adjustment resolves the contradiction by maintaining sufficient stability through moderate alkali content while preventing excessive sodium that would harm selectivity, thereby achieving an optimal balance between stability and product distribution.
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 process achieves higher selectivity and extended catalyst lifespan, leading to increased yields of olefinic products and improved process efficiency in converting oxygenates to olefins.
Implementation Method 1
a process for the conversion of oxygenates to olefins employing a catalyst comprising a zeolitic material
Data Source
AI summary
The present invention relates to a process for the conversion of oxygenates to olefins comprising(i) providing a gas stream comprising one or more oxygenates; and(ii) contacting the gas stream with a catalyst;wherein the catalyst comprises a zeolitic material having an MFI, MEL, and/or MWW-type framework structure comprising YO2 and X2O3, wherein Y is a tetravalent element, and X is a trivalent element,said zeolitic material being obtainable and/or obtained according to a method comprising(1) preparing a mixture comprising one or more sources for YO2, one or more sources for X2O3, and one or more solvents; and(2) crystallizing the mixture obtained in step (1) to obtain a zeolitic material having an MFI, MEL and/or MWW-type framework structure;wherein the mixture crystallized in step (2) contains 3 wt.-% or less of the one or more elements M based on 100 wt.-% of YO2, wherein M stands for sodium.