Core-Shell OCM Catalysts for High-Selectivity Methane Conversion
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Solution Overview
Problem
The commercialization of the oxidative coupling of methane (OCM) and oxidative dehydrogenation of ethane (ODH) reactions is hindered by the lack of effective catalysts and catalytic forms, with existing catalysts facing challenges in efficiency and selectivity, particularly at high temperatures.
Innovation Solution
Development of catalysts with specific surface areas and thermal stability, including nanostructured and bulk catalysts, combined with dopants and supports, to enhance the oxidative coupling of methane and oxidative dehydrogenation of alkanes, utilizing catalyst beds with tailored compositions and structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional heterogeneous catalysts are used for oxidative coupling of methane, then the reaction can proceed at high temperatures, but the catalyst lacks effectiveness and adequate activity leading to insufficient methane conversion
Solution Approach 1:
The patent changes the physical and chemical parameters of the catalyst by creating a core-shell structure with specific size ranges (0.5-5 micrometers), controlling shell thickness (50-500 nanometers), and selecting specific materials (perovskite core, alumina shell) to achieve both high activity and effectiveness for methane conversion
Solution Approach 2:
The patent employs composite catalyst structures combining different materials with complementary properties - perovskite cores for catalytic activity, alumina shells for stability and surface area, and optional magnetic nanoparticle cores for additional functionality and ease of separation, creating a multi-component system that resolves the contradiction between activity and effectiveness
2Productivity
If catalyst surface area is increased to enhance activity, then more active sites are available for reaction, but the catalyst bed complexity and transport limitations increase
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the shell portion provides high surface area for catalytic activity while the core provides structural support, allowing different regions of the catalyst particle to have optimized properties for their specific functions without increasing overall bed complexity
Solution Approach 2:
The patent utilizes porous alumina shells with controlled porosity to provide high surface area for catalytic reactions while maintaining appropriate mass and heat transport properties, resolving the contradiction between needing high surface area for activity and avoiding transport limitations that would increase complexity
3Productivity
If reaction temperature is increased to improve methane activation, then reaction rate increases, but energy consumption and coke formation increase
Solution Approach 1:
The patent changes the catalytic parameters by using perovskite materials with specific crystal structures and compositions that lower the activation energy barrier for methane conversion, allowing the reaction to proceed at lower temperatures with high activity, thus reducing energy consumption while maintaining productivity
Solution Approach 2:
The patent converts the potential harm of high temperature operation (energy waste and coke formation) into a benefit by designing a catalyst that enables low-temperature high-activity operation, where the core-shell structure's high surface area and active sites allow efficient reaction at reduced temperatures, turning the limitation into an advantage
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 proposed catalysts and methods improve the efficiency and selectivity of OCM and ODH reactions, enabling higher hydrocarbon production with reduced thermal input and coke formation, thus advancing the commercial viability of these processes.
Implementation Method 1
the reactants must diffuse to and/or adsorb onto the catalyst surface
Implementation Method 2
Catalysis is the process in which the rate of a chemical reaction is either increased or decreased by means of a catalyst
Implementation Method 3
This reaction is exothermic (ΔH=−67 kcals/mole)
Data Source
AI summary
Catalysts and catalytic methods are provided. The catalysts and methods are useful in a variety of catalytic reactions, for example, the oxidative coupling of methane.