KL Zeolite Dealkylation Catalyst for Converting C9+ Aromatics to BTX
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Solution Overview
Problem
Existing catalytic reforming processes struggle to efficiently convert C9+ aromatic hydrocarbons into light aromatic hydrocarbons like BTX, with limited control over product distribution and high yields of heavy aromatics that cannot be used as gasoline blending components, leading to market limitations and inefficiencies.
Innovation Solution
A method using a dealkylation catalyst comprising KL zeolite and platinum with a modifying metal, such as Group IIA metals or rare earth metals, to convert C9+ aromatic hydrocarbons into light aromatics, and a dehydrogenation catalyst for C9+ paraffins to produce C9+ aromatics followed by dealkylation, enhancing the conversion and yield of light aromatics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional catalytic reforming is used to convert naphtha components, then the carbon number of products remains the same as reactants, but the yield of heavy aromatics (C9+) is high and cannot be used as gasoline blending components
Solution Approach 1:
The patent introduces a dual-function catalyst system that changes the reaction pathway parameters. The first catalyst promotes dehydrocyclization to form C9+ aromatics, while the second catalyst (zeolite with metal components) promotes transalkylation reactions that transfer alkyl groups between aromatic molecules, converting C9+ aromatics into lighter aromatics (C6-C8) suitable for gasoline blending. This parameter change in reaction mechanism resolves the contradiction by transforming the product distribution.
Solution Approach 2:
The patent uses C9+ aromatic hydrocarbons as an intermediary substance. First, they are produced via dehydrocyclization of paraffins, then they serve as reactants for transalkylation reactions where they transfer alkyl groups to other aromatic molecules, ultimately forming lighter aromatics. This intermediary role allows the system to convert heavy aromatics into usable gasoline components through controlled chemical transformation.
2Productivity
If the severity of reforming operation is increased to improve conversion of light alkanes, then dehydrocyclization reaction rate increases, but selectivity deteriorates and hydrocracking reaction is promoted causing hydrogen consumption increase
Solution Approach 1:
The patent segments the catalytic reforming process into two distinct stages with different catalyst functions. The first stage uses a catalyst optimized for dehydrocyclization to convert paraffins to aromatics with high selectivity. The second stage uses a zeolite-based catalyst optimized for transalkylation to convert C9+ aromatics to lighter aromatics. This segmentation allows each stage to operate at optimal conditions without the negative effects of excessive severity, maintaining both high conversion and high selectivity.
Solution Approach 2:
The patent implements dynamic control of reaction conditions and catalyst composition. The dual-catalyst system allows flexible adjustment of reaction pathways - the first catalyst dynamically produces C9+ aromatics which then serve as substrates for the second catalyst's transalkylation activity. This dynamic interaction between catalysts enables the system to maintain high selectivity while achieving high overall conversion by adapting the reaction mechanism to the evolving product distribution.
3Quantity of substance
If dehydrocyclization reaction of C6 and C7 light alkanes is increased to improve aromatic yield, then conversion increases, but hydrocracking reaction is promoted causing decrease in liquid product yield
Solution Approach 1:
The patent changes the reaction parameters by introducing a second catalytic function focused on transalkylation. Instead of relying solely on dehydrocyclization which has inherent hydrocracking side reactions, the system adds transalkylation as a dominant pathway. This parameter change redirects the reaction toward aromatic formation through alkyl transfer rather than through high-severity dehydrocyclization, thereby maintaining aromatic yield while preserving liquid product through reduced hydrocracking.
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
High conversion rates and yields of light aromatic hydrocarbons, such as BTX, are achieved by directing the dehydrocyclization and dealkylation of C9+ paraffins and aromatics, improving the utilization value of these hydrocarbons.
Implementation Method 1
contacting a C9+ aromatic hydrocarbon with a dealkylation catalyst comprising a KL zeolite and platinum and a modifying metal supported thereon in the presence of hydrogen to obtain a light aromatic hydrocarbon
Implementation Method 2
contacting a feedstock comprising a C9+ paraffinic hydrocarbon with a dehydrogenation catalyst to perform dehydrocyclization reaction
Implementation Method 3
in the presence of hydrogen
Data Source
AI summary
A method for producing light aromatic hydrocarbons from C9+ aromatic hydrocarbons includes a step of contacting a C9+ aromatic hydrocarbon with a dealkylation catalyst comprising a KL zeolite, and platinum and a modifying metal supported thereon in the presence of hydrogen, to obtain a light aromatic hydrocarbon. The modifying metal is selected from the group consisting of Group IIA metals and rare earth metals. By using a Pt/KL catalyst comprising a specific modifying metal in the dealkylation reaction of C9+ aromatic hydrocarbons for producing light aromatic hydrocarbons, the method shows the advantages of high conversion rate of feedstock, high yield of light aromatic hydrocarbons, good reaction selectivity.