Small Crystal FAU Zeolite Catalyst for Low Benzene Olefin Ratio Alkylation
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Solution Overview
Problem
Current benzene alkylation processes with olefins face challenges in selectivity and energy efficiency due to the formation of 'heavies' and the need for high benzene to olefin ratios, which increase energy costs and operational concerns related to toxic catalysts like hydrogen fluoride.
Innovation Solution
The use of small crystal, acidic FAU molecular sieves as catalysts in solid catalytic processes allows for lower benzene to olefin ratios without significant production of 'heavies', enhancing selectivity and reducing energy costs by maintaining high mono-alkylated aromatic selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If solid catalysts are used for benzene alkylation, then hydrogen fluoride toxicity and corrosiveness are eliminated, but the benzene to olefin ratio must be increased to greater than 15:1 to minimize heavies production
Solution Approach 1:
The patent changes the physical parameter of the solid catalyst by controlling crystallite size to be less than 1 micrometer. This parameter change in catalyst structure enables the process to operate at lower benzene to olefin ratios (4:1 to 12:1) while maintaining high selectivity and minimizing heavies production, thus resolving the contradiction between eliminating HF toxicity and reducing benzene excess.
Solution Approach 2:
The patent uses composite catalyst formulations combining small crystallite FAU molecular sieve with other catalyst components. This composite approach enhances catalytic activity and selectivity, allowing operation at lower benzene to olefin ratios without increasing heavies production, thereby resolving the contradiction between using solid catalysts and minimizing benzene excess.
2Manufacturing precision
If the benzene to olefin ratio is increased to minimize heavies production, then selectivity to alkylbenzene is improved, but energy costs for benzene recovery and recycling increase significantly
Solution Approach 1:
The patent changes the catalyst crystallite size parameter to less than 1 micrometer, which dramatically improves catalytic activity and selectivity. This enables the process to achieve high alkylbenzene selectivity at lower benzene to olefin ratios (4:1 to 12:1), thereby reducing the energy required for benzene recovery and recycling operations.
3Use of energy by moving object
If the benzene to olefin ratio is reduced to decrease energy costs, then energy efficiency is improved, but heavies production increases significantly
Solution Approach 1:
The patent changes the catalyst crystallite size parameter to less than 1 micrometer, which enhances catalytic activity and selectivity. This enables operation at lower benzene to olefin ratios (4:1 to 12:1) while maintaining high selectivity to alkylbenzene and minimizing heavies production to less than 6 mass percent, thus resolving the contradiction between energy efficiency and heavies production.
4Quantity of substance
If homogeneous hydrogen fluoride catalyst is used, then benzene to olefin ratio can be kept low (6:1 to 8:1), but operational concerns arise due to toxicity and corrosiveness
Solution Approach 1:
The patent changes the physical parameter of solid catalysts by reducing crystallite size to less than 1 micrometer. This parameter change enables solid catalysts to achieve performance comparable to homogeneous HF catalysts, allowing operation at low benzene to olefin ratios (4:1 to 12:1) while maintaining the safety advantages of solid catalysts without HF toxicity and corrosiveness.
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
This approach achieves a mono-alkylated aromatic selectivity of at least 92% with reduced 'heavies' production, even at lower benzene to olefin ratios, improving the economic attractiveness and environmental safety of the alkylation process.
Implementation Method 1
The alkylation conditions comprise the presence of homogeneous or heterogeneous alkylation catalyst such as aluminum chloride, hydrogen fluoride, or zeolitic catalysts
Implementation Method 2
solid, high activity catalysts containing small crystallite FAU molecular sieve
Data Source
AI summary
The alkylation of aromatic compound with acyclic mono-olefin is effected at low aromatic compound to mono-olefin ratios with reduced co-production of heavies. In the processes a small crystal, acidic FAU molecular sieve is used as a catalyst under alkylation conditions. This invention also relates to catalysts containing small crystal, acidic FAU molecular sieve and at least one other acidic catalytic component.