C8 Aromatic Catalyst Reducing Ethylbenzene via Composite Zeolite
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Solution Overview
Problem
Existing methods for producing C8 aromatic hydrocarbons, such as mixed xylenes, often result in high ethylbenzene content, which decreases the efficiency of p-xylene separation processes and increases overall process costs.
Innovation Solution
A catalyst comprising a mixed support of MFI-type zeolite with reduced palladium inside its pores and a second zeolite with specific pore size, combined with metals like platinum, rhenium, or molybdenum, is used to convert alkyl aromatic hydrocarbons into C8 aromatic hydrocarbons with reduced ethylbenzene content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional methods are used to produce C8 aromatic hydrocarbons, then production yield is achieved, but ethylbenzene content becomes high which reduces separation efficiency
Solution Approach 1:
The patent modifies the catalyst's chemical composition parameters by incorporating specific metal combinations (Pt, Pd, Mo, or W) and adjusting their ratios, along with controlling the silica-alumina ratio of the zeolite support. These parameter changes enable the catalyst to selectively promote desired reactions while suppressing ethylbenzene formation, achieving both high productivity and low ethylbenzene content (<1.5 wt%).
Solution Approach 2:
The patent employs a composite catalyst material consisting of multiple metal components (Pt, Pd, Mo, and/or W) supported on a zeolite structure with specific silica-alumina ratio. This composite structure combines the advantages of different metals and the zeolite support to achieve high C8 aromatic hydrocarbon yield while maintaining low ethylbenzene content through synergistic catalytic effects.
2Productivity
If high ethylbenzene content is produced, then reaction throughput is maintained, but separation process efficiency decreases and costs increase
Solution Approach 1:
By changing the catalyst's compositional parameters to include specific metal ratios and silica-alumina ratios, the reaction selectivity is improved. This allows maintaining high reaction throughput while producing C8 aromatic hydrocarbons with ethylbenzene content below 1.5 wt%, thereby reducing the energy and cost burden on subsequent separation processes.
3Manufacturing precision
If catalyst selectivity is improved to reduce ethylbenzene, then separation efficiency increases, but catalyst complexity increases
Solution Approach 1:
The patent uses a composite catalyst material with multiple metal components (Pt, Pd, Mo, and/or W) on a zeolite support. While this composite structure provides high selectivity for reducing ethylbenzene content, it does increase catalyst composition complexity. However, this complexity is justified by the significant improvement in product quality and separation efficiency.
Solution Approach 2:
The patent applies local quality by distributing different metal components throughout the catalyst structure and controlling their local concentrations. This ensures uniform selectivity across the catalyst bed, maintaining high ethylbenzene reduction efficiency while managing the overall catalyst complexity through controlled spatial distribution of active components.
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 catalyst achieves high yield of C8 aromatic hydrocarbons with ethylbenzene content reduced to less than 1.5% by weight, improving the efficiency of subsequent p-xylene separation processes and reducing overall process costs.
Implementation Method 1
a catalyst which is useful for converting a feedstock containing alkyl aromatic hydrocarbons to C8 aromatic hydrocarbons such as mixed xylenes through disproportion/transalkylation/dealkylation
Implementation Method 2
olefins such as ethylene, propylene, etc. are preferably removed by hydrogenation as fast as possible when they are generated by the dealkylation in the conversion process
Data Source
AI summary
A catalyst and a preparation method thereof, the catalyst providing a high production yield of C8 aromatic hydrocarbons in the conversion of a feedstock containing alkyl aromatics to C8 aromatic hydrocarbons such as mixed xylene through at least one of disproportionation, transalkylation, and dealkylation while reducing a content of ethylbenzene in the product.