Zeolite Catalyst Metal Sintering Resistance
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Solution Overview
Problem
Catalysts for hydrocarbon conversion, such as zeolites, face issues with metal sintering due to process temperatures and catalyst regeneration, leading to a decrease in metal surface area and catalyst performance, specifically activity and selectivity.
Innovation Solution
A catalyst is synthesized with a three-dimensional interconnecting crystalline tetrahedral framework containing silicon, aluminum, phosphorus, and other elements, with a deposited metal from Group 6, 7, 8, 9, or 10, such as platinum, which is incorporated into the zeolite framework and calcined to prevent sintering, maintaining high selectivity for aromatics like benzene, toluene, and xylenes over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the catalyst is used at high process temperatures and undergoes regeneration, then the hydrocarbon conversion activity is maintained, but metal sintering occurs leading to decreased metal surface area and catalyst performance
Solution Approach 1:
A silica intermediary layer is deposited on the catalyst surface between the metal particles and the external environment. This silica layer acts as a physical barrier that prevents metal particle migration and coalescence during high-temperature operation and regeneration cycles, thereby maintaining metal surface area while allowing the catalyst to operate at high temperatures for sustained activity
Solution Approach 2:
The silica layer is deposited on the catalyst surface before the catalyst is deployed for hydrocarbon conversion. This preliminary protective coating is in place before any sintering can occur, preemptively preventing metal particle aggregation during subsequent high-temperature operation and regeneration processes
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 maintains high selectivity and activity for converting C2-C12 hydrocarbons into aromatics, with the presence of elements like germanium in the framework and deposited metals like platinum resisting sintering, ensuring consistent performance over time.
Implementation Method 1
The reaction mixture is heated to form crystals and then cooled
Implementation Method 2
calcining the zeolite, said calcining occurring after preparation of the zeolite, before depositing at least one metal selected from Group 10 on the zeolite or after depositing at least one metal selected from Group 10 on the zeolite
Data Source
AI summary
This invention is for a catalyst for conversion of hydrocarbons. The catalyst contains a zeolite with one element from Group 13, Group 14, or the first series transition metals and, optionally, germanium and/or aluminum in the zeolite framework. At least one Group 10 metal, such as platinum, is deposited on the zeolite. Examples of the elements in the framework are tin, boron, iron or titanium. The catalyst is prepared by synthesizing a zeolite with one element from Group 13, Group 14, or the first series transition metals and, optionally, germanium and/or aluminum in the zeolite framework; depositing the metal; and calcining after preparation of the zeolite and before or after depositing the metal. The catalyst may be used in a process for the conversion of hydrocarbons, such as propane to aromatics, by contacting the catalyst with alkanes having 2 to 12 carbon atoms per molecule and recovering the product.