DBD Plasma Reactor for Methane Coupling
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Solution Overview
Problem
Conventional methods for converting methane to valuable hydrocarbons like ethylene and ethane require high temperatures and energy-intensive processes, leading to inefficiencies and environmental concerns, while existing non-thermal plasma technologies face challenges in maintaining reaction efficiency and catalyst stability.
Innovation Solution
A dielectric barrier discharge plasma reactor with packed dielectric particles of specific sizes and gap distances, utilizing low temperature plasma to regenerate particles and optimize methane conversion and selectivity, without additional thermal energy or oxidants, and employing a method to remove carbon deposition using the same plasma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperature (over 1,000°C) is used to thermally activate C-H bonds for non-oxidative coupling of methane, then methane conversion to C2+ hydrocarbons is achieved, but energy consumption is excessive and reaction conditions become severe
Solution Approach 1:
The patent replaces thermal activation (mechanical/thermal system) with plasma activation (electrical/energy field system). Instead of using high temperature thermal energy to break C-H bonds, the invention uses non-thermal plasma electrons with high energy to directly activate methane molecules at ambient or low temperatures, thereby resolving the contradiction between achieving methane conversion and reducing energy consumption
Solution Approach 2:
The patent changes the energy delivery parameter from thermal energy (temperature) to electrical energy (plasma). By using dielectric barrier discharge plasma, the system maintains low bulk gas temperature while generating highly reactive species through electrical discharge, thus achieving high methane conversion without the excessive energy consumption associated with high-temperature thermal processes
2Productivity
If high temperature (at least 800°C) is used for oxidative coupling of methane with catalysts and oxygen co-reactants, then C2 compounds are produced with relatively high yields, but separation burden increases due to air separation unit and production of pure products
Solution Approach 1:
The patent extracts oxygen from the reaction system by using non-oxidative coupling conditions. Instead of using oxygen co-reactants that require air separation and produce complex product mixtures requiring purification, the invention performs methane coupling in the absence of oxygen, directly producing C2+ hydrocarbons and hydrogen that can be separated more simply
Solution Approach 2:
The patent inverts the conventional oxidative coupling approach by using non-oxidative conditions. Rather than adding oxygen to promote coupling (which creates separation problems), the invention removes oxygen from the system and uses plasma activation to achieve coupling, thereby simplifying the product separation and purification process
3Productivity
If conventional thermochemical reactor processes are used for methane coupling, then C2 compounds are produced, but the severe reaction conditions limit the choice of reactor materials and reaction catalysts
Solution Approach 1:
The patent replaces the thermal field with a plasma field, allowing the use of materials that cannot withstand high temperatures. The dielectric barrier and reactor components can be made from conventional materials that are compatible with plasma processing, greatly expanding material selection flexibility while maintaining high C2 compounds production
Solution Approach 2:
The patent changes the operating temperature parameter from high temperature (800-1000°C) to ambient or low temperature plasma conditions. This parameter change enables the use of a broader range of reactor materials and catalysts that would decompose or degrade under conventional high-temperature conditions, thereby improving adaptability and versatility
4Productivity
If dielectric particles are used in DBD plasma reactor for non-oxidative coupling of methane, then methane conversion and product selectivity are improved, but coke deposition deactivates the bed over time
Solution Approach 1:
The patent implements periodic regeneration of the dielectric bed by alternating between methane coupling reaction mode and air oxidation regeneration mode. During regeneration, air is passed through the bed at elevated temperature to burn off deposited coke, restoring the dielectric particles to their initial active state. This periodic action maintains both high productivity and reliability over extended operation
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 enables efficient non-oxidative coupling of methane to produce C2+ hydrocarbons and hydrogen at room temperature, maintaining catalyst stability and reducing energy consumption and carbon deposition, thereby improving reaction efficiency and environmental impact.
Implementation Method 1
a dielectric barrier discharge plasma reactor including dielectric particles in a packed-bed in a discharge zone
Implementation Method 2
a non-thermal plasma technology has been intensively and extensively studied recently since it directly and efficiently utilizes accelerated electrons and ions to activate the C—H bonds of methane molecules at relatively low temperature
Implementation Method 3
a method of regenerating dielectric particles by removing coke, which is produced by side reactions, from the dielectric particles deactivated by the coke by using a low temperature plasma in an oxidizing atmosphere in the reactor
Data Source
AI summary
Provided are a dielectric barrier discharge (DBD) plasma reactor including dielectric particles in a packed-bed in a discharge zone, e.g., a DBD plasma reactor for non-oxidative coupling of methane in which an average gap distance between dielectric particles in the packed-bed is adjusted to improve methane conversion and/or product selectivity; a method of regenerating dielectric particles including removing coke, which sis produced by side reactions, from the dielectric particles deactivated by the coke by using a low temperature plasma in an oxidizing atmosphere in the reactor; a method of manufacturing C2+ hydrocarbons, the method including converting methane into C2+ hydrocarbons including ethylene and/or ethane by non-oxidative coupling of methane in the reactor; and a method of manufacturing hydrogen, the method including generating hydrogen from methane by non-oxidative coupling of methane in the reactor.