Homogeneous Catalysts via Solution Combustion Synthesis
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Solution Overview
Problem
Catalyst materials used in the oxidative coupling of methane (OCM) process degrade over time due to preferential enrichment of active components on the catalyst surface, leading to reduced efficacy and selectivity.
Innovation Solution
The solution combustion synthesis (SCS) method is employed to prepare deactivation-resistant catalysts, such as Sr—Al, La—Sr—Al, and Na2WO4—Mn/SiO2, allowing for tailored metal ratios and homogeneous distribution of active species, preventing surface composition changes and maintaining catalyst performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional incipient wetness impregnation method is used to prepare catalyst, then active components are enriched on the catalyst surface initially, but the catalyst degrades over time due to surface ablation and composition changes
Solution Approach 1:
The solution combustion synthesis method performs preliminary homogeneous distribution of active components throughout the catalyst bulk before the catalyst is even used. This preliminary action ensures that when surface ablation occurs during operation, fresh active components are continuously exposed from the interior, maintaining catalyst performance over time rather than degrading.
Solution Approach 2:
The invention changes the synthesis method from traditional incipient wetness impregnation to solution combustion synthesis. This parameter change in the manufacturing process fundamentally alters the spatial distribution of active components from surface-enriched to homogeneous throughout the bulk, thereby resolving the contradiction between initial surface composition and long-term stability.
2Manufacturing precision
If high CH4/O2 ratio is used in OCM process, then C2 selectivity is high, but methane conversion is low
Solution Approach 1:
The homogeneous distribution of active components created by solution combustion synthesis enables the catalyst to maintain optimal composition at the surface throughout operation. This parameter change in catalyst structure allows the system to achieve both high C2 selectivity and high methane conversion simultaneously, breaking the traditional trade-off between these two parameters.
3Duration of action of moving object
If catalyst surface is ablated over time, then exposed surface material composition changes, but catalyst efficacy is lost
Solution Approach 1:
The solution combustion synthesis method performs preliminary homogeneous distribution of active components throughout the catalyst bulk before the catalyst is even used. This preliminary action ensures that when surface ablation occurs during operation, fresh active components are continuously exposed from the interior, maintaining catalyst performance over time rather than degrading.
Solution Approach 2:
The invention applies homogeneity by ensuring uniform distribution of active components throughout the entire catalyst bulk rather than concentrating them only on the surface. This homogeneous structure ensures that any surface loss during operation does not compromise overall catalyst efficacy, as the bulk material maintains consistent composition and activity.
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 SCS method results in catalysts with high C2 yields and ethylene/ethane ratios, with Na2WO4—Mn/SiO2 demonstrating exceptional stability and activity, achieving maximum C2 yields comparable to the highest recorded values, while maintaining performance over extended periods without deactivation.
Implementation Method 1
The solution combustion synthesis (SCS) method is employed to prepare deactivation-resistant catalysts
Data Source
AI summary
A method for making a metal oxide material and catalyzing the oxidative coupling of methane, including mixing a metal cation-containing oxidizer portion and a reducing fuel portion with water to define an aqueous solution, evaporatively removing water from the aqueous solution to yield a concentrated liquid, burning the concentrated liquid yield an homogeneous metal oxide powder, flowing methane from a first source and oxygen from a second source over the homogeneous metal oxide powder, and catalyzing an oxidative coupling of methane reaction with the homogeneous metal oxide powder. The homogeneous metal oxide powder contains metal oxides selected from the group including LaSrAlO4, LaAlO3, Sr3Al2O6, Na2WO4—Mn/SiO2, and combinations thereof.