Supported OCM Catalyst Composition for Selectivity and Strength
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Solution Overview
Problem
Existing OCM catalyst systems suffer from low catalytic activity, low product selectivity, and poor mechanical integrity, making them unsuitable for commercial applications due to issues like gas bypassing and deactivation, especially under severe reaction conditions.
Innovation Solution
A catalyst composition represented by the formula (AEaRE1bRE2cATdOx)/MmOn, where AE is an alkaline earth metal, RE1 and RE2 are different rare earth elements, AT is a redox agent or third rare earth element, and MmOn is an oxide catalyst support, with controlled particle size and thermal treatment to balance surface area, pore volume, and mechanical strength, enhancing catalytic activity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional OCM catalyst systems are used, then catalytic activity can be achieved, but product selectivity deteriorates due to formation of thermodynamically stable carbon oxide products
Solution Approach 1:
The patent employs a composite catalyst system comprising multiple metal oxides (manganese oxide, alkali metal oxide, and rare earth metal oxide) combined with a porous support material. This composite structure synergistically enhances both catalytic activity for methane conversion and selectivity toward C2+ hydrocarbons by distributing active sites and controlling reaction pathways, preventing over-oxidation to COx while maintaining high productivity
Solution Approach 2:
The catalyst utilizes a porous support structure with controlled pore size and distribution. The porous architecture provides high surface area for active catalyst dispersion, facilitates mass transport of reactants and products, and through appropriate pore size control, enhances selectivity by favoring the formation and diffusion of C2+ hydrocarbons while limiting the formation of thermodynamically stable COx products
2Reliability
If catalyst particle size is reduced to reduce gas bypassing, then product selectivity improves, but mechanical integrity deteriorates
Solution Approach 1:
The porous support material provides structural framework that maintains mechanical integrity even at reduced particle sizes. The interconnected pore structure distributes mechanical stresses throughout the particle, preventing fragmentation while maintaining the small particle size necessary to minimize gas bypassing and enhance product selectivity in short bed reactors
Solution Approach 2:
The composite nature of the catalyst, with active metal oxide components dispersed on a robust porous support, provides both the mechanical strength needed for handling and the small effective particle size for high selectivity. The support acts as a structural backbone that maintains integrity while allowing the active components to function at high surface area-to-volume ratios
3Productivity
If catalyst particle size is reduced to enhance catalytic performance, then mass and heat transfer resistance decreases, but manufacturing complexity increases
Solution Approach 1:
The patent specifies controlled ranges for critical parameters including particle size (0.1-2.0 mm), pore size (0.5-5.0 μm), and surface area (0.5-5.0 m²/g) to optimize the balance between catalytic performance and manufacturability. These parameter specifications enable standard manufacturing processes to produce catalysts with the required performance characteristics, avoiding excessive complexity while maintaining high activity through reduced mass and heat transfer resistance
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 system achieves high product selectivity and mechanical strength, suitable for industrial-scale OCM processes, with improved catalytic activity and reduced gas bypassing, enabling efficient production of C2+ hydrocarbons.
Implementation Method 1
the oxide catalyst support has a water sorption volume of at least 0.2 cc/g
Implementation Method 2
catalyst compositions used for the oxidative coupling of methane (OCM)... commercially high value chemicals, such as ethylene and other C2+ hydrocarbons, can potentially be produced
Data Source
AI summary
The invention relates to a composition containing an oxide supported oxidative coupling of methane catalyst having an excellent balance of catalytic activity and selectivity while retaining desired levels mechanical stability suitable for commercial reactor application. Particularly, the inventive catalyst is an oxide supported catalyst with the oxide catalyst support having a spherical diameter of less than 2 mm and a surface area of less than less than 9.5 m2/g while retaining a water sorption volume of at least 0.2 cc/g. The invention further provides a method for preparing such a composition containing an oxide supported catalyst, using a combination of thermal treatment of the oxide catalyst support, active component impregnation and followed up by calcination. Additionally, the invention also describes a process for producing C2+ hydrocarbons, using such a catalyst composition.