Methane Conversion Reactor with H2-Permeable Membrane
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Solution Overview
Problem
Existing methods for converting methane to value-added products like hydrogen and C2 hydrocarbons are inefficient due to kinetic and thermodynamic constraints, leading to low methane conversion rates and high environmental costs, particularly due to carbon dioxide emissions.
Innovation Solution
A reactor design with a H2-permeable wall separating two gas volumes, where methane is converted to hydrogen and C2 hydrocarbons in the presence of a catalyst, with hydrogen being transported through a dense mixed ionic-electronic permeable thin film membrane to enhance conversion efficiency and product selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If indirect conversion or oxidative coupling is used to convert methane to value-added products, then product formation is achieved, but carbon dioxide emissions increase and energy consumption increases
Solution Approach 1:
The patent extracts hydrogen from the reaction mixture by transporting it through a membrane to a second volume, removing it from the system before it can participate in further reactions that would produce carbon dioxide. This extraction of the problematic intermediate (hydrogen) prevents the formation of harmful byproducts while maintaining high methane conversion efficiency
Solution Approach 2:
The membrane acts as an intermediary between the first volume (where methane conversion occurs) and the second volume (where hydrogen is removed). This intermediary structure enables selective hydrogen transport without requiring direct contact between reactants and products, allowing efficient methane conversion while preventing carbon dioxide formation through controlled hydrogen removal
2Object-generated harmful factors
If existing non-oxidative direct methane conversion is used, then carbon dioxide emissions are reduced, but methane conversion rate remains low due to kinetic and thermodynamic constraints
Solution Approach 1:
The patent introduces dynamic control of hydrogen partial pressure through the membrane transport system. By continuously removing hydrogen from the first volume and controlling its partial pressure, the system dynamically shifts reaction equilibrium and enhances methane conversion rate without compromising the low carbon dioxide emission advantage of non-oxidative conversion
Solution Approach 2:
The patent changes the partial pressure parameter of hydrogen through selective membrane transport. By maintaining low hydrogen partial pressure in the first volume through continuous removal in the second volume, the system overcomes thermodynamic constraints and achieves high methane conversion rates while preserving the environmental benefits of non-oxidative conversion
3Stability of the object's composition
If hydrogen is retained in the first volume during methane conversion, then reaction equilibrium is maintained, but methane conversion is limited by thermodynamic constraints
Solution Approach 1:
The patent segments the reaction system into two distinct volumes separated by a membrane. The first volume maintains reaction equilibrium conditions for methane conversion, while the second volume selectively removes hydrogen. This segmentation allows the system to simultaneously maintain equilibrium stability and enhance conversion by removing products in a controlled manner
Solution Approach 2:
The membrane serves as an intermediary that selectively transports hydrogen between the first volume (where equilibrium is maintained) and the second volume (where hydrogen is removed). This intermediary structure enables the system to maintain reaction equilibrium in the first volume while continuously enhancing methane conversion through controlled hydrogen removal in the second volume
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
This approach increases methane conversion by up to 40% while maintaining product selectivity for C2 hydrocarbons and aromatics, reducing the need for intermediate energy-intensive steps and minimizing carbon dioxide emissions.
Implementation Method 1
an H2-permeable wall includes a dense mixed ionic-electronic permeable thin film membrane supported on a porous wall and transports H2 generated in the first volume by the conversion reaction to the second volume
Implementation Method 2
A catalyst can be provided in or adjacent to the first volume for catalyzing the conversion of methane to the valued-added products
Implementation Method 3
The NDMC can take place within a reactor heated to an elevated temperature
Data Source
AI summary
Non-oxidative direct methane conversion (NDMC) to value-added products, such as H2, C2 hydrocarbons, and aromatics, occurs within a reactor heated to an elevated temperature. The reactor can have a first volume, where a feed gas including methane is provided, separated from a second volume, where a sweep gas is provided, by a dense thin film membrane supported on a porous wall. The thin film membrane is a mixed ionic-electronic permeable membrane that allows H2 generated in the first volume to be transported to the second volume for removal by (or reaction with) the sweep gas. A catalyst can be provided in or adjacent to the first volume. For example, the catalyst can be a metal doped quartz material (e.g., Fe(c)SiO2) or a metal/zeolite material (e.g., Mo/ZSM5). Methane conversion and/or product selectivity in the reactor can be manipulated by control of gas flow rates, reaction temperatures, and/or feed and sweep gas compositions.