Zeolite Beta Composite Catalyst for Xylene Yield
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Solution Overview
Problem
Conventional methods for converting heavy reformate to xylenes yield insufficient xylenes to meet demand, and existing catalysts fail to efficiently produce commercially valuable xylenes due to equilibrium constraints and kinetic limitations in transalkylation reactions.
Innovation Solution
Development of zeolite composite catalysts with an ordered/disordered mesostructure and hydrothermal stability, comprising zeolite beta and additional metal or metal oxides, which are synthesized through a method involving dissolution in an alkaline solution, pH adjustment, aging, and calcination to achieve high surface area and specific pore structures for enhanced transalkylation activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional transalkylation methods are used to convert heavy reformate to xylenes, then the process is simple and well-established, but the xylene yield is insufficient to meet demand due to equilibrium constraints
Solution Approach 1:
The patent changes the chemical parameters of the reaction system by introducing dealkylation reactions alongside transalkylation. This shifts the overall reaction equilibrium by removing alkyl groups as byproducts, thereby breaking the equilibrium constraints that limit conventional transalkylation and enabling higher xylene yields.
Solution Approach 2:
The patent employs a composite catalyst system combining zeolite beta with other catalyst components. This composite catalyst enables simultaneous dealkylation and transalkylation reactions, overcoming the equilibrium limitations of single-reaction systems and achieving superior xylene production.
2Productivity
If existing catalysts are used for transalkylation, then the catalyst structure is simple and easy to manufacture, but the catalytic activity is limited by kinetic constraints
Solution Approach 1:
The patent uses a composite catalyst comprising zeolite beta combined with other catalytic materials. This composite structure provides multiple active sites that facilitate both dealkylation and transalkylation reactions, significantly enhancing transalkylation activity while managing the increased structural complexity through systematic catalyst design.
Solution Approach 2:
The patent utilizes zeolite beta, a porous material with specific pore structures that provide high surface area and accessible active sites. The porous structure enhances mass transfer and catalytic activity, overcoming kinetic limitations while maintaining a manufacturable catalyst form through established porous material synthesis methods.
3Quantity of substance
If heavy reformate is subjected to transalkylation alone, then the reaction conditions are mild and energy consumption is low, but the xylene selectivity is insufficient due to multiple parallel reactions
Solution Approach 1:
The patent changes the reaction pathway parameters by introducing dealkylation reactions that compete with and suppress unwanted parallel reactions. This parameter change in the reaction mechanism improves xylene selectivity by providing an alternative pathway that reduces the impact of equilibrium-constrained transalkylation and minimizes byproduct formation.
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 zeolite composite catalysts exhibit high ethyl-dealkylation and methyl-transalkylation activities, significantly improving the yield of xylenes and maintaining acidity advantages, thereby addressing the insufficiency in xylene production from heavy reformate.
Implementation Method 1
zeolite composite catalysts and methods of using the same to convert heavy reformate to xylenes
Implementation Method 2
dissolution in an alkaline solution, pH adjustment, aging, and calcination to achieve high surface area and specific pore structures for enhanced transalkylation activity
Data Source
AI summary
Embodiments of zeolite composite catalysts and methods of producing the zeolite composite catalysts are provided, where the methods comprise dissolving in an alkaline solution a catalyst precursor comprising at least one mesoporous zeolite while heating, stirring, or both to yield a dissolved zeolite solution, where the mesoporous zeolite has a molar ratio of SiO2/Al2O3 of at least 30, where the mesoporous zeolite comprises zeolite beta, adjusting the pH of the dissolved zeolite solution, aging the pH adjusted dissolved zeolite solution to yield solid zeolite composite from the dissolved zeolite solution, and calcining the solid zeolite composite to produce the zeolite composite catalyst, where the zeolite composite catalyst has a mesostructure comprising at least one disordered mesophase and at least one ordered mesophase, and where the zeolite composite catalyst has a surface area defined by the Brunauer-Emmett-Teller (BET) analysis of at least 600 m2/g.