Zeolite Composite Catalyst for Linear Alkylbenzene Isomerization Control
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Solution Overview
Problem
Existing catalysts for benzene alkylation face challenges such as high energy costs, low selectivity, and environmental concerns, particularly in producing linear alkylbenzenes with desired 2-phenyl content for surfactant production, due to issues like skeletal isomerization and catalyst deactivation.
Innovation Solution
A catalyst comprising a microporous crystalline zeolite with a specific composition and a rare earth-substituted zeolite, intermingled into single particles, which minimizes skeletal isomerization and maintains high 2-phenyl content and linearity, reducing energy consumption and extending catalyst life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If existing solid catalytic processes are used to avoid hydrogen fluoride, then safety and environmental issues are improved, but energy costs increase and selectivity decreases
Solution Approach 1:
The patent uses a composite catalyst system combining two different zeolite types (USY zeolite with rare earth elements and a second zeolite with specific SiO2/Al2O3 ratio) to achieve both safety benefits of solid catalysts and improved energy efficiency and selectivity through synergistic catalytic properties
Solution Approach 2:
The patent modifies catalyst parameters by incorporating rare earth elements (La, Ce, Pr, Nd) into the USY zeolite framework and controlling the SiO2/Al2O3 ratio of the second zeolite, which changes the catalytic activity and selectivity to reduce energy requirements while maintaining safety
2Productivity
If existing catalysts are used to produce linear alkylbenzenes, then production capability is improved, but skeletal isomerization increases reducing 2-phenyl content
Solution Approach 1:
The patent creates catalysts with localized active sites of different strengths by combining two zeolite types with distinct pore structures and acid site distributions, where each zeolite component provides specific catalytic functions that together achieve high productivity with minimal skeletal isomerization
Solution Approach 2:
The patent uses the second zeolite (with SiO2/Al2O3 ratio of 15-50) as an intermediary component that moderates the strong acid sites of the USY zeolite, reducing skeletal isomerization while maintaining alkylation activity through cooperative catalysis
3Productivity
If existing catalysts are used for alkylation, then conversion is achieved, but catalyst deactivation occurs reducing operational life
Solution Approach 1:
The patent designs a catalyst system where the second zeolite component provides structural stability and resistance to deactivation, allowing the catalyst to maintain conversion activity over extended periods; the rare earth-modified USY zeolite can be regenerated while the overall system maintains long operational life
Solution Approach 2:
The patent incorporates rare earth elements into the USY zeolite framework in advance to strengthen the catalyst structure against deactivation mechanisms, providing prior protection that extends catalyst life while maintaining conversion capability
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 new catalyst achieves stable production of linear alkylbenzenes with desired 2-phenyl content and linearity, reducing energy costs and extending catalyst life, while maintaining product quality and regenerability.
Implementation Method 1
The catalysts are for use in the alkylation of aromatic compounds. In one embodiment, the aromatic compound is benzene and the olefin is a linear olefin. The catalyst comprises a first zeolite and a second zeolite.
Implementation Method 2
a first zeolite comprising a microporous crystalline zeolite having a layered framework of at least AlO2 and SiO2 tetrahedral units and a composition on an as-synthesized and anhydrous basis expressed by an empirical formula of: Mmn+Rrp+Al1-xExSiyOz
Data Source
AI summary
A catalyst is presented for use in the production of linear alkylbenzenes. The catalyst includes two zeolites combined to improve the quality of the linear alkylbenzenes. The catalyst includes a first zeolite that is UZM-8 and a second zeolite that is a low silica to alumina ratio zeolite. The second zeolite is also cation exchanged with a rare earth elements to provide a zeolite that increases the alkylation of benzene while reducing the amount of skeletal isomerization.