Modified Beta Zeolite for Higher Olefin Interconversion Selectivity
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Solution Overview
Problem
Existing catalyst systems in selective olefin cracking processes do not efficiently produce optimal proportions of high-value products like propylene and ethylene, necessitating improved catalysts and systems to enhance yield.
Innovation Solution
A framework-substituted beta zeolite catalyst system is used, where a portion of the BEA aluminosilicate framework aluminum atoms are substituted with titanium, zirconium, or hafnium atoms, and optionally combined with framework-substituted ultra-stable Y zeolite, to facilitate olefin interconversion reactions under specific temperature, pressure, and residence time conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional catalyst systems are used in selective olefin cracking, then the process can operate, but the yield of high-value products (propylene and ethylene) is not optimal
Solution Approach 1:
The patent modifies the catalyst's chemical composition parameters by substituting framework aluminum atoms with titanium, zirconium, or hafnium atoms in the beta zeolite structure. This changes the catalyst's acid site characteristics and electronic properties, leading to improved selectivity for propylene and ethylene production while maintaining stable performance
Solution Approach 2:
The patent creates a composite catalyst system by combining framework-substituted beta zeolite with framework-substituted ultra-stable Y zeolite. This composite approach integrates the shape-selective properties of beta zeolite with the high activity of USY zeolite, achieving optimal product distribution and enhanced catalyst reliability
2Productivity
If hydrogen-transfer and cyclization reactions occur, then various hydrocarbon products are formed, but the yield of desired propylene and ethylene decreases
Solution Approach 1:
The patent introduces local quality changes by substituting specific framework aluminum atoms with titanium, zirconium, or hafnium atoms at controlled levels (0.1-10 mol%). This creates localized modifications in acid site strength and distribution, suppressing hydrogen-transfer and cyclization reactions while maintaining cracking activity for propylene and ethylene production
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 modified catalyst system enhances the production of propylene and ethylene by minimizing hydrogen-transfer and cyclization reactions, resulting in higher yields of these high-value products.
Implementation Method 1
The modified catalyst system enhances the production of propylene and ethylene by minimizing hydrogen-transfer and cyclization reactions
Data Source
AI summary
Methods for interconverting olefins in an olefin-rich hydrocarbon stream include contacting the olefin-rich hydrocarbon stream with a catalyst system in an olefin interconversion unit to produce an interconverted effluent comprising ethylene and propylene. The contacting may be conducted at a reaction temperature from 450 °C to 750 °C, a reaction pressure from 1 bar to 5 bar, and a residence time from 0.5 seconds to 1000 seconds. The catalyst system includes a framework-substituted beta zeolite. The framework-substituted beta zeolite has a *BEA aluminosilicate framework that has been modified by substituting a portion of framework aluminum atoms of the *BEA aluminosilicate framework with beta-zeolite Al-substitution atoms independently selected from the group consisting of titanium atoms, zirconium atoms, hafnium atoms, and combinations thereof.